NCEA Level 3 Biology Externals by BIOZONE International

Textbook Lite | Activities | Study Guide 3NCEA LEVEL BIOLOGY EXTERNALS

Kent Pryor I have a BSc from Massey University majoring in zoology and ecology and taught secondary school biology and chemistry for 9 years before joining BIOZONE as an author in 2009.

Meet the writing team

for design and graphics support, Paolo Curray and Malaki Toleafoa for IT support, Debbie Antoniadis and Arahi Hippolite for office handling and logistics, and the BIOZONE sales team. Tracey Senior Author Lissa Author Kent Author Richard Founder & CEO All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electrical, mechanical, photocopying, recording or otherwise, without the permission of BIOZONE International Ltd. This book may not be re-sold. The conditions of sale specifically prohibit the photocopying of exercises, worksheets, and diagrams from this book for any reason. Purchases of this book may be made direct from the publisher: www. BIOZONE .co.nz BIOZONE International Ltd. P.O. Box 5002 Hamilton 3242, New Zealand Telephone: (07) 856 8104 Fax: (07) 856 9243 Email: Website:sales@biozone.co.nzwww. BIOZONE.co.nz Second edition 2017 ISBN: 978-1-927309-56-8 Copyright © 2016 Richard Allan Published by BIOZONE International Ltd Printed by Wickcliffe Solutions www.wickliffe.co.nz

Lissa Bainbridge-Smith

I have been writing resources for students since 1993. I have a Ph.D in biology, specialising in lake ecology and I have taught both graduate and undergraduate biology.

: The staff at BIOZONE, including Nell Travaglia and Holly

Tracey Greenwood

I worked in industry in a research and development capacity for 8 years before joining BIOZONE in 2006. I have a M.Sc from Waikato University.

Reconstruction of A. afarensis, the famously named "Lucy", one of the longest-lived and best-known hominins, with fossils from more than 300 individuals. Dated at 3.85-2.95 million years, this east African species survived for more than 900,000 years, more than four times as long as our own species has been around.

Thanks to Coon

NCEA LEVEL 3 BIOLOGY EXTERNALS

PHOTO: © Kennis & Kennis | kenniskennis.com

Richard Allan

I have had 11 years experience teaching senior secondary school biology. I have a Masters degree in biology and founded BIOZONE in the 1980s after developing resources for my own students.

Cover photograph Australopithecus afarensis

AS 3.5 Evolutionary processes leading to speciation

Achievement criteria and explanatory notes 101 75 The Role of Variation in Populations 103 76 Mutations 104 77 Beneficial Mutations 105 78 Sickle Cell Mutation 106 79 Heterozygous Advantage 107 80 Gene Duplication and Evolution ..................... 109 81 An Introduction to Evolutionary Processes 111 82 Genetic Drift Affects Gene Pools 113 83 Adaptations and Fitness ................................ 114 84 Natural Selection Affects Gene Pools 115 85 Stabilising Selection for Human Birth Weight . 116 86 Directional Selection in Moths ........................ 117 87 Directional Selection in Darwin's Finches 118 88 Disruptive Selection in Darwin's Finches 119 89 Selection for Skin Colour in Humans 120 90 What You Know So Far 122 CODES: Activity is marked: to be done when completed

Contents Using This Resource v Using the Tab System vii How To Scaffold an NCEA Style Answer viii AS 3.3 Plant and animal responses to their external environment Achievement criteria and explanatory notes 1 1 Why Organisms Need to Respond 3 2 Types of Stimuli 4 3 Kineses 5 4 Taxes 7 5 Pheromones 9 6 Migration 10 7 Migration Patterns 11 8 Examples of Migration 12 9 Bird Migrations in New Zealand 14 10 Migratory Navigation in Birds 15 11 Cuckoo Migrations 17 12 Sun Compass Navigation 18 13 Homing Behaviour in Insects 20 14 Homing in Salmon 21 15 Plant Responses 22 16 Tropisms 23 17 Investigating Phototropism 24 18 Investigating Gravitropism ................................ 25 19 Investigating Gravitropism in Seeds 26 20 Nastic Responses 27 21 What You Know So Far ..................................... 29 22 NCEA Style Question: Migration 30 23 NCEA Style Question: Plant Responses 31 24 KEY TERMS AND IDEAS ................................. 32 25 Astronomical Cycles 33 26 Biological Clocks 34 27 Biological Clocks and the Environment ............ 35 28 Biological Rhythms 36 29 Circadian Rhythms in NZ Birds 38 30 Human Biological Rhythms 39 31 Interpreting Actograms 41 32 Activity Patterns in Animals 42 33 Plant Rhythms 44 34 Photoperiodism in Plants 46 35 What You Know So Far 48 36 NCEA Style Question: Biological Clocks in Animals 49 37 NCEA Style Question: Biological Clocks in Plants 50 38 KEY TERMS AND IDEAS .. 51 39 Species Interactions 52 40 Mutualism involving Animals 54 41 Mutualism involving Plants 56 42 Interpreting Predator-Prey Relationships 58 43 The Effects of Interspecific Competition 59 44 Identifying Species Interactions in Ecosystems .. 61 45 What You Know So Far 62 46 NCEA Style Question: Interspecific Relationships ............................... 63 47 KEY TERMS AND IDEAS 64 48 Intraspecific Communication 65 49 Pukeko Communication ................................... 67 50 Recording Animal Behaviour 68 51 Social Groupings 69 52 Social Organisation 70 53 Cooperative Behaviour 71 54 How Cooperative Behaviour Improves Survival 73 55 Cooperative Defence 75 56 Cooperative Attack 76 57 Cooperative Foraging 77 58 Conflict in Social Groups 78 59 Intraspecific Competition and its Effects 80 60 Social Hierarchy in Pukekos 82 61 Monkey Hierarchy 84 62 Hierarchies in Baboons 85 63 Territories and Home Ranges 86 64 Home Ranges and Resources in Baboons 87 65 Home Ranges in Karearea 88 66 Yellowhead Territories 89 67 Breeding Behaviour 90 68 Reproductive Strategies .................................... 92 69 Mating Systems and Parental Care 94 70 Territories and Breeding Behaviour 95 71 What You Know So Far ..................................... 96 72 NCEA Style Question: Cooperative Behaviour 97 73 NCEA Style Question: Territories 99 74 KEY TERMS AND IDEAS .............................. 100

158 What You Know So Far 227

121 NCEA Style Question: Patterns of Evolution 166

97 Postzygotic Reproductive Isolating Mechanisms 131

115 Changes in Landscape and Speciation 156

143 General Primate Characteristics 198

93 The Biological Species Concept 125

128 The Evolution of Horses 176

174 The Dispersal of Modern Humans 248

103 Polyploidy and Speciation in Melicytus 139

119 Evolution in Hebe 164

142

163 Palaeolithic Tool Use 234

160 KEY TERMS AND IDEAS 229

124 The Evidence for Evolution 170

122 KEY TERMS AND IDEAS 167

167 Communication and Changes in the Brain 239

173 The Origin of Modern Humans 246

100 Divergence in Allopatric Populations 135

141 NCEA Style Question: Evidence for Evolution 194 KEY TERMS AND IDEAS 195

177 Problems with Interpretation: H. floresiensis 252

125 Fossils 171

152

150 Trends in Skull Anatomy 208

CODES: Activity is marked: to be done when completed

QuestioningAPPENDIX

108 Divergent Evolution 145

171 NCEA Style Question: Cultural Evolution 244

175 New Findings: Denisovans 250

terms and Birth Weight Data ............... 269

127 Transitional Fossils 175

145 The Primate Hand 201

159 NCEA Style Question: Biological Evolution 228

168 Mesolithic Culture 240 169 Neolithic Culture 241

Contents

98 Allopatric Speciation 132

107 KEY TERMS AND IDEAS ............................... 144

114 The Geological History of New Zealand 155

131 Ocean Island Colonisers 179

140 What You Know So Far 193

105 What You Know So Far 142

123 The Common Ancestry of Life 168

120 What You Know So Far 165

.............................

162 Trends in Palaeolithic Tool Cultures 232

137 Homologous DNA Sequences 190

136 Molecular Clock Hypothesis 189

...................................

96 Prezygotic Reproductive Isolating Mechanisms 128

99 Small Flies and Giant Buttercups 134

118 Adaptive Radiation in Wrens 162

135 Homologous Proteins...................................... 187

153 The Importance of Ardi 213 154 Bipedalism and Nakedness 215 155 Adaptations for Bipedalism 216

149 Human Evolution: Probable Phylogenies 206

161 Cultural Evolution 230

AS 3.6 Trends in human evolution

172 KEY TERMS AND IDEAS 245

.....................................................

117 Origin of New Zealand Parrots 160

176 New Interpretations: The Neanderthals 251

138 Developmental Evidence for Evolution............ 191

109 Convergent Evolution 146

170 What You Know So Far 243

111 Adaptive Radiation in Mammals 150

181 NCEA Style Question: Patterns of Dispersal ... 257

182 A Summary of Trends in Human Evolution 258

104 Polyploidy and the Domestication of Wheat 140

166 Art and Spirituality 237

183 Scholarship Question: Return of the Dodo 262

INDEX

113 The Rate of Evolutionary Change ................... 154

134 Vestigial Structures 186

92 KEY TERMS AND IDEAS 124

95 Ring Species: The Greenish Warbler 127

110 Coevolution 148

102 Sympatric Speciation 138

133 Homologous Structures 185

112 Divergent Evolution in Ratites 152

157 Hominin Data Sheets 219

164 Fire 235

146 Primate Skull Features 202

144 Hominins and Hominoids 200

94 What Are Ring Species? 126

178 Dating a Prehistoric Site 253

151 Trends in Brain Volume 210 Trends in Dentition 212

180 What You Know So Far 256

Achievement criteria and explanatory notes 196

106 NCEA Style Question: Speciation 143

130 Biogeographical Evidence 178

132 Continental Drift and Evolution 181

184 Scholarship Question: Stickleback Speciation . 266

PHOTO CREDITS 270 271

.....

165 Shelter and Clothing 236

126 Interpreting the Fossil Record 173

139 The Evolution of Novel Forms 192

101 Polyploidy as a Source of Variation 136

129 The Evolution of Whales 177

148 Trends in Human Evolution: Overview 204

147 Human Skull Anatomy 203

91 NCEA Style Question: Mutation and Evolution 123

156 Analysis of Lucy's Skeleton 218

179 Problems With Dating: H. naledi 255

116 Speciation in Giant Land Snails ...................... 158

Review

• Includes a question based on key terms

• A check list explanatorycriteriaachievementofandnotes

Sections within a chapter share the same structure. They correspond to natural topic breaks within the Achievement Standard.

• NCEA activitiesclustersquestionsstyleconcludeofrelated

• Create your own summary for review

• A check list of what you need to know

Key terms and ideas

Test

• Hints help you to focus on what is important

The outline of the chapter structure below will help you to navigate through the material in each chapter.

KNOW © 1988-2016 BIOZONE International Photocopying Prohibited 20 1. Why did moving the pine cones around the wasp nest result to the wasp being unable to find the nest? 2. (a) After a foraging trip, a Cataglyphis ant was displaced to another point some distance away. On the diagram shown right, draw in a line indicating the direction the ant travelled when released: (b) Explain why the ant moved in the direction you drew: Key Idea Homing is the ability of an animal to return to its home site after being displaced and it involves navigation. In many insects, homing is important in increasing foraging efficiency because it reduces energy expenditure. Homing (returning to a home site) is distinct from migration, although navigation is involved in both behaviours. Homing behaviour often relies on the recognition of familiar landmarks, especially where the distances involved are relatively short. Navigation, often assisted by the use of trail pheromones, is also involved in the foraging behaviour of many insects. Step 1: Orientation flight While a female wasp was in the burrow, Tinbergen placed a circle of pine cones around the nest entrance. When she emerged, the wasp reacted by carrying out a wavering orientation flight before flying off. Step 2: Return flight During her absence, the pine cones were moved away from the burrow leading to the nest. Returning to the nest with prey, the wasp orientated to the circle of pine cones, not the nest entrance. Homing and navigation in wasps The beewolf Philanthus digs a nest in sand. It is a predator of bees and captures and paralyses bees as food for its larvae during development. The paralysed bee is taken back to the wasp's underground nest, where the wasp lays its eggs in the still living body. In a well-known experiment to test the homing behaviour of this wasp, a scientist named Tinbergen, carried out a 2-step experiment. (After Tinbergen, 1951. The Study of Instinct. Oxford University Press, London) Homing in ants Cataglyphis desert ants use polarised light to navigate while foraging, often pausing and turning 360° to apparently note the position of the Sun and plane of light. When they discover a food source, they return directly to the nest as shown right. This ability to determine the direction to the nest reduces travel time when returning to the nest, making foraging more efficient. Homing Behaviour in Insects13 Nest Food source ForagingjourneyReturntrip Nest Ant captured at food source tripForaging Ant released at this point Wasp Wasp Pine PreyPineNest(bee) Beewolf Philanthus triangulum 3.0Alvesgaspar Cataglyphis ants collect a beetle LINK 12 WEB 13 REVISE 29 © 1988-2016 BIOZONE International PhotocopyingWhatProhibited You Know So Far: Orientation in Space21 Summarise what you know about this topic so far under the headings provided. You can draw diagrams or mind maps, or write short notes to organise your thoughts in preparation for the NCEA style essay question that follows. Use the points in the introduction and the hints provided to help you: Nastic responses HINT: How do nastic responses differ from tropisms? What is their purpose? Tropisms HINT: Include definitions and explain the mechanisms of phototropism and gravitropism. Taxes and kineses HINT: Be sure to include definitions, adaptive value, and examples of both types of responses Homing and migration HINT: Include a definition as well as reference to navigation and the benefits and costs of migration. TEST 30 ISBN: 978-1-927309-56-8 Photocopying Prohibited NCEA Style Question: Migration22 Sooty shearwater The sooty shearwater Puffinus griseus muttonbird or titi) migrates up to 65,000 km. It is one of the longest migrations of any animal. From October to March, sooty shearwaters raise their chicks (which takes about 100 days) on oceanic islands around the sub-Antarctic region of New Zealand. During the breeding season, tens of thousands of chicks are taken by commercial hunters. From April to May, they begin migrating to specific areas of the sub-Arctic, arriving from June to July for the Northern Hemisphere summer. The sooty shearwater is often seen behind fishing trawlers picking up scraps. 1. Discuss the migratory behaviour of the sooty shearwater as it travels from sub-Antarctic waters to sub-Arctic waters (you may use extra paper if needed). Explain why it would undertake such a long migration Explain some of the methods it may be using to navigate Suggest reasons why its numbers have been dropping 2. Suggest why the sooty shearwater begins its return journey in October when North Pacific Ocean productivity is greater than South Pacific Ocean productivity. Month Latitude oceansofProductivitym(g-2d F M M S O N D J 60 0.10.20.40.50.8-2040 J JA A Pacific South Breed BreedMigration of Positionbirds of birds vs ocean productivity Trade winds of Pacific OceanFlight of two sooty shearwaters TEST 32 ISBN: 978-1-927309-56-8 Photocopying Prohibited KEY TERMS AND IDEAS: Orientation in Space24 1. (a) What is the name given to a plant growth response to directional light? (b) What is the name given to a plant growth response to gravity? (c) What is the name given to a plant response that is independent of stimulus direction? (d) What plant hormone is principally responsible for the phototropic effect? 2. (a) The honeybee waggle dance communicates the location of a food source based on: star compass navigation local geography and landmarks / sun compass navigation (delete two) (b) The honeybee round dance communicates that a food source is close by. Does it also communicate direction? Y N 3. (a) What responses are being shown by the orchid in the photo (left): (b) What is the stimulus involved? (c) How are these responses adaptive? 4. Match the following words with their definitions: dispersal A Animal orientation and movement in response to a directional stimulus. kinesis B The process of using environmental cures to determine position in reference to a goal. migration C A one-way movement away from an area in response to environmental change. navigation D A plant growth response to a directional external stimulus. taxis E The long distance movement of animals from one region to another, usually seasonally. tropism F A non-directional animal orientation response in which the speed or movement or rate of turning is proportional to stimulus intensity 5. The photo (left) shows swarming behaviour in locusts: (a) What event is likely to be occurring here? (b) What distinguishes this behaviour from a migration? (c) What is the likely cue for this behaviour? (d) How is this response adaptive? 3.0CCTangopaso

• Other questions test your understanding of the section content

• A list of key terms

Using This Resource

• Your summary will help you with the NCEA style question

Activities

Introduction

• The KEY IDEA provides your focus for the activity

• Questions review the content of the page

• These enable you to practise your NCEA exam skills

BIOZONE's NCEA Level 3 Biology Externals contains material to meet the needs of New Zealand students studying NCEA Biology Level 3 External Achievement Standards. The NCEA Level 3 Biology Externals is compliant with Level 8 of the NZ Curriculum (Nature of Science – The Living World) and the NCEA Biology Level 3 External Achievement Standards. A wide range of activities will help you to build on what you already know, explore new topics, work collaboratively, and practise your skills in data handling and interpretation. We hope that you find this resource useful and that you make full use of its features.

• Annotated diagrams help you understand the content

France. Sickles:

The activities form most of this book. They are numbered sequentially and each has a task code identifying the skill emphasised. Each activity has a short introduction with a key idea identifying the main message of the page. Most of the information is associated with pictures and diagrams, and your understanding of the content is reviewed through the questions. Some of the activities involve modelling and group work.

Key Idea: The Mesolithic period is marked climatically by the change from glacial to warmer climates, and archaeologically by the refinement and further development of human tools. The Mesolithic (Middle Stone Age) period occurred in Europe 12,000-3000 years ago, as the last glacial period ended. The tools produced at the time were small bladed geometric stone tools (microliths), and were often fitted into a handle of wood or bone. Mesolithic people used a wide variety of hunting,

Understanding the activity coding system and making use of the online material identified will enable you to get the most out of this resource. The chapter content is structured to build knowledge and skills but this structure does not necessarily represent a strict order of treatment. Be guided by your teacher, who will assign activities as part of a wider programme of independent and group-based work.

Look out for these features and know how to use them:

Mesolithic Culture168

The chapter introduction provides you with a summary of the achievement criteria and explanatory notes as identified in the Achievement Standard. A check list of what you need to know to meet the knowledge requirements of the standard is provided on the second page of the introduction. Use the check boxes to identify and mark off the points as you complete them. A list of key terms for the chapter is included.

A TASK CODE on the page tab identifies the type of activity. For example, is it primarily information-based (KNOW), or does it involve modelling (PRAC)? A full list of codes is given on the following page but the codes themselves are relatively self explanatory.

LINK tabs at the bottom of the activity page identify activities that are related in that they build on content or apply the same principles to a new situation.

WEB 168 LINK 161 Trends in evolutionhumanAchievement Standard 3.6 Key terms Biological evolution ape Au. Ardipithecusafarensis Australopithecusramidus spp. bipedal hominoidhominidgracileDmanisiDenisovanscarrying(bipedalism)anglefossils H.H.H.H.H.H.H.Homoerectusergasterfloresiensishabilisheidelbergensisneanderthalensissapiens primate Paranthropus spp. hypothesisOuthypothesismultiregionalDispersalWernicke'sPalaeolithicOldowanNeolithicMousterianMesolithicBroca'sAcheulianCulturalvalgussexualrobustprognathicprehensiledimorphismangleevolution(tool)area(tool)(tool)areaofAfrica Explanatory notes: Trends in human evolution numberActivity Trends in human evolution refer to changes over time in relation to… c 1 Human biological evolution begins with early bipedal hominins and may require comparison with living hominids. These trends involve: 1 20 Skeletal changes linked to bipedalism. b Changes in skull and endocranial features that reveal changes in brain structure. c Changes in the manipulative ability of the hand. c 2 Human cultural evolution including: 25 34 a The use of tools (stone, wood, and bone) and changes in tool technology. 39 44 b The use of fire c Clothing d Abstract thought, including communication, language, and art. Food gathering, including hunter gatherer to domestication of plants and animals. 48 69 Shelter including caves, temporary settlements and permanent settlements. c 3 Patterns of dispersal of hominins. Hominins refers to living and fossil species belonging to the human lineage. Recognisable trends characterise the evolution of humans: bipedalism, increase in brain size, reduction in teeth, reduction in facial projection, and increasing importance of art, spirituality, tool technology, and sociality. Achievement criteria and explanatory notes Achievement criteria for achieved, merit, and excellence c A Demonstrate understanding of trends in human evolution: Use biological ideas to describe trends in human evolution. c M Demonstrate in-depth understanding of trends in human evolution: Use biological ideas to explain how or why trends in human evolution occur.

fishing, and food gathering techniques, which may have arisen because the warming climate would have resulted in increased productivity. The Mesolithic occurred during the current Holocene epoch, which is relatively warm compared to the previous epoch, the Pleistocene. The warmer climate resulted in glacial retreats, the growth of forests in Europe and deserts in North Africa, and the disappearance of the animals hunted during the glacial period.

WEB tabs at the bottom of the activity page alert the reader to the Weblinks resource, which provides external, online support material for the activity, usually in the form of an animation, video clip, photo library, or quiz. Bookmark the Weblinks page (see next page) and visit it frequently as you progress through the book. and 9500 years ago. It was found in These two sickles are made of flint embedded into a handle made of horn (below, right) and an antler (right). tools were used to cut the grasses to gather their seeds and date from the Mesolithic

KNOW © 1988-2016 BIOZONE International ISBN: 978-1-927309-56-8 Photocopying Prohibited 240 1. The Mesolithic culture replaced the Upper Palaeolithic culture. When did the Mesolithic culture begin? 2. (a) Describe the key features that characterise the Mesolithic culture: (b) How did the Mesolithic culture differ from the Upper Palaeolithic culture? 3. Explain the significance of the warmer climate experienced during the Mesolithic period: Bone fish hook: This fish hook dates from the Mesolithic period and was found in Sweden. Microlith: Made of flint or chert (a sedimentary rock). Microliths formed the points of hunting weapons such as spears. This microlith was found in the Tourasse cave, France. Harpoon: This flat harpoon is made of bone, and dates between 12,000

Such

period. Antler handle Horn handle Single flint blade Three flint cuttingembeddedmicrolithstocreateedge Tools of the Mesolithic period DescouensDidier DescouensDidier

E Demonstrate comprehensive understanding of trends in human evolution: Link biological ideas about trends in human evolution. This may involve justifying, relating, evaluating, comparing and contrasting, and analysing using scientific evidence.

Free response questions allow you to use the information provided to answer questions about the content of the activity, either directly or by applying the same principles to a new situation. In some cases, an activity will assume understanding of prior content.

Using the Tab System

Corrections and clarifications to current editions are always posted on the weblinks page

section

Bookmark the weblinks

The tab system is a useful system for quickly identifying related content and online support. Links generally refer to activities that build on the information in the activity in depth or extent. A link may also reflect on material that has been covered earlier as a reminder for important terms that have already been defined. In the example below for the activity "Mesolithic Culture", the weblink 168 provides information about stone tools. Activity 161 directs back to an overview of aspects of cultural evolution. The weblinks code is always the same as the activity number on which it is cited. On visiting the weblinks page (below), find the number and it will correspond to one or more external websites providing a video or animation of some aspect of the activity's content. Occasionally, the weblink may provide a bank of photographs where images are provided in colour.

TEST = test your understanding

Activitybook

Hyperlink to the external website page.

This WEBLINKS page provides links to external websites with supporting information for the activities. These sites are distinct from those provided in the BIOLINKS area of BIOZONE's web site. For the most part, they are narrowly focussed animations and video clips directly relevant to some aspect of the activity on which they are cited. They provide great support to help your understanding of basic concepts.

Bookmark weblinks by typing in the address: it is not accessible directly from BIOZONE's website

KNOW = content you

Weblinks

161

REVISE = review the material in the

168

(b) How did the Mesolithic culture differ from the Upper Palaeolithic

3. Explain the significance of the warmer climate experienced during

Link

focus

need to know

WEB LINK

interpretation

KNOW

DATA = data handling and

Activities are coded

Connections are made between activities in different sections of the syllabus that are related through content or because they build on prior knowledge.

Chapter in the in the book

activityAccessNZL3E-9568www.biozone.co.nz/weblink/page:theexternalURLforthebyclickingthelink

PRAC = a paper practical or a practical

www.biozone.co.nz/weblink/NZL3E-9568

fundamental process in evolution. Discuss the role of mutation in the evolution of populations. In your answer you should define mutation and explain how mutation can change in the genetic makeup of a population and lead to speciation. You may use examples to illustrate your argument:

• Defining, drawing, annotating, or giving a description of a process is achievement level only.

• Explaining how a process works, why it works, and how changes to it may affect an outcome is merit level.

In order to gain the highest possible mark in these questions, you need to lay out your answer in a clear and logical way so that the examiner can easily see how you have demonstrated your understanding of the topic.

• Linking biological ideas, comparing and contrasting, analysing, or justifying ideas is excellence level.

The following example question shows how an answer can be built up from a simple definition, through explanation, to comparisons and linking of

The mutationterm is

Gene duplications can be very important in evolution because they provide (a) more useful copies of the same proteins (giving a selective advantage through a dosage effect) or (b) redundancy of gene function so that extra copies may be adapted for other functions. The duplication and then change to alleles leads to a change in allele frequencies (evolution) and has been important in the genetic divergence of many taxa, including primates.

In some cases in plants, entire genomic duplications (polyploidy) can result in immediate genetic isolation of an organism. Sometimes, in plants, a hybridisation event between two species may produce an infertile hybrid, which can reproduce asexually (vegetatively). Hybrids often show greater fitness than either parent. This is an example of instant speciation. A subsequent polyploidy event in the infertile hybrid can make it fertile (producing even sets of chromosomes for pairing at meiosis). This type of speciation (hybridisation followed by polyploidy) has been important in the evolution of wheat and many other plants, including New Zealand species of Melicytus.

Mutationideas.isa

A mutation is a change to the DNA sequence. Gene mutations can involve small changes, e.g. to a single nucleotide or a triplet, and may result in a non-functional protein or a new useful protein variant. Other mutations may involved larger scale parts of chromosomes (e.g. gene duplications) or even genomes (e.g. polyploidy). Mutations that occur in the gametes (germline mutations) may be inherited and so can affect later populations.

Mutations are the source of all new alleles. Changes to proteins are most commonly harmful and are quickly removed from the population's gene pool because they do not contribute to fitness (successful survival and reproduction). However, sometimes new alleles can be created that are beneficial to the organism in some way, e.g. a germ line mutation in the gene for an enzyme in a plant may enable it to break down a natural toxin in the soil more quickly. If the environment of the time provides a selective advantage to the plants with the mutation, the mutation will become relatively more common in the population (by the process of natural selection). Over time, the plants with the mutant allele will be favoured and the mutation will become more common (the frequency of that allele will increase relative to other alleles). This process is evolution.

How to Scaffold an NCEA Style Answer

The plants with the mutation may also be able to escape competition and colonise new areas, so they can potentially become isolated from plants without the mutation. Once they are separated ecologically, gene flow between the populations will slow and genetic differences between the populations will increase. Genetic drift and natural selection will affect each population differently and reproductive isolating mechanisms will develop within each population, isolating them further. When speciation is complete, the two populations (one with the mutation and one without) will be unable to interbreed naturally and gene flow between them will stop (a new species forms).

The external NCEA exams require you to demonstrate your understanding of a particular concept by providing a written paragraph or essay. Generally the question is designed as an open answer (meaning there is no definitive answer) in which you can demonstrate your level of understanding. The question may give you some guidance as to what you should include in your answer, such as definitions of certain terms or to provide specific examples.

The difference between you obtaining an achievement, merit, or excellence grade depends on how well you demonstrate your understanding of a concept.

evolution.duplicationsandtoExamplesexplained.speciationfrequenciesmutationofconsequencesThedescribed.ofgeneticofThedefinedsignificancemutationtothemakeupapopulationisDifferenttypesofmutationsarebrieflydescribed.Fitnessisdefined.possibleabeneficialtoalleleandareillustrateroleofgenegenomicin

c 3 Interspecific relationships to include competition for resources, mutualism, and exploitation (herbivory, predation, and parasitism). 39 44

c 4 Intraspecific relationships to include competition for resources, territoriality, hierarchical behaviour, cooperative interactions, and reproductive behaviour. 48 70

The short and long term responses of plants and animals to their external environment are adaptive, enabling organisms to maximise fitness in their ecological niche. Responses include orientation in space and time as well as responses to other organisms in their environment.

c A Demonstrate understanding of the responses of plants and animals to their external environment: Describe plant and animal responses to their external environment, including the process(es) within each response and/or the adaptive advantage provided for the organism in relation to its ecological niche.

5 Biotic factors are those arising from living things or their activities, e.g. competition.

Common terms adaptive kinesishomingdispersalOrientationlearnedinnateenvironmentaladvantagecuebehaviourbehaviourinspace( pl. kineses) taxisphytohormonenavigationnasticmigrationresponse( pl. taxes) Orientationtropism in time territorysocialbehaviourreproductivemutualismkinhierarchyexploitationcooperativecompetitioncommunicationaltruismagonisticaggressionSpecieszeitgebertidalphotoperiodismphaseperiodlunarfreeexogenousentrainmentendogenousrhythmcircadianbiologicalbiologicalannualactogramrhythmclockrhythm(daily)runningperiodrhythm(ofrhythm)shiftrhythminteractionsbehaviourbehaviourselectionbehaviour

Responses to the external environment Standard

c 1 Orientation in space to include tropisms and nastic responses in plants, and taxes, kineses, homing, and migration in animals. 1 - 20

Key terms

Achievement criteria and explanatory notes

c E Demonstrate comprehensive understanding of the responses of plants and animals to their external environment: Link biological ideas to explain why the responses provide an adaptive advantage for the organism in relation to its ecological niche. This may involve justifying, relating, evaluating, comparing, contrasting, and analysing the responses of plants and animals to their external environment.

3.3

6 Abiotic factors are factors in the physical environment, e.g. light-dark cycles.

Explanatory notes: Plant and animal responses numberActivity Responses are selected from those relating to…

Achievement

c 2 Orientation in time to include annual, daily, lunar and tidal rhythms. 25 - 34

Achievement criteria for achieved, merit, and excellence

c M Demonstrate in-depth understanding of the responses of plants and animals to their external environment: Use biological ideas to explain how responses occur and why the responses provide an adaptive advantage for the organism in relation to its ecological niche.

The external environment includes both biotic and abiotic factors…

c Describe intraspecific competition for resources, the behaviours associated with it (e.g. agonistic behaviour), and its consequences (hierarchies, territories, home ranges).

Activities 25 38

c Describe and explain how plant and animal behaviours are linked to natural environmental rhythms that occur with a predictable frequency. Define the term biological rhythm.

c Explain photoperiodism in plants, including the role of phytochrome in measuring daylength by resetting the biological clock (entrainment). Distinguish between long-day and short-day plants.

c Describe and explain the characteristics of daily, tidal, lunar, and annual rhythms. Explain how an organism's biological rhythms provide an adaptive advantage in its ecological niche.

Activities 1 24

Intraspecific relationships

c Describe examples of cooperative behaviour and explain its adaptive advantage.

c Describe and explain species interactions, including mutualism, exploitation (herbivory, predation, parasitism), and competition for resources. Identify the adaptive advantages of the relationship to one or both of the parties involved.

c Using examples, explain how navigation is involved in migratory and homing behaviour.

Orientation in time

c Describe examples of taxes, the environmental cue involved in each case, and the adaptive advantage of the behaviour in relation to the organism's niche.

What you need to know for this Achievement Standard

c Describe reproductive behaviours in animals and explain their adaptive advantage, including reference to courtship behaviours, mating systems, and parental care.

c Distinguish different types of animal organisation, solitary, or groups with or without a social structure. Describe the adaptive advantage of group and social behaviours.

Orientation in space

By the end of this section you should be able to:

Activities 48 73

c Describe and explain diurnal, nocturnal, and crepuscular activity patterns in animals with circadian rhythms. Explain the adaptive value of these activity patterns in each case.

c Explain the evolutionary consequences of interspecific competition (niche differentiation).

JennyAKA Ladley Uni. of Canterbury

Activities 39 - 47

By the end of this section you should be able to:

Interspecific relationships

By the end of this section you should be able to:

c Explain how social insects communicate directional information to enable others to locate resources. Identify the mechanisms involved and the adaptive advantage of the behaviour.

c Describe how animals communicate. Interpret ethograms and record animal behaviour using an appropriate system to identify the type of behaviour and its intensity.

c Distinguish between taxes and kineses and identify them as innate responses.

c Describe and explain the two mechanisms underlying biological rhythms: the endogenous biological clock and the external zeitgeber (environmental cue).

By the end of this section you should be able to:

c Explain the role of territories and hierarchies in allocating resources and reducing aggression.

c Describe examples of kineses, the environmental cue involved in each case, and the adaptive advantage of the behaviour in relation to the organism's niche.

c Describe migratory behaviour, including at least one example from New Zealand. Explain the adaptive advantage of migration, despite its costs. Distinguish migration from dispersal.

c Describe examples of homing behaviour and distinguish it from migration. Explain the adaptive advantage of the behaviour and its dependence on environmental cues.

c Interpret actograms recording the circadian rhythms of animals. Demonstrate an understanding of the free running period, phase shift, and entrainment.

f Involves a biological clock

The position of the Sun is important in honey bee navigation.

Key Idea: An organism's response to the environment is called its behaviour. Adaptive behaviours increase an organism's fitness (genetic contribution to the next generation). The environment in which any organism lives is always changing, for example, light to dark or warm to cool. Organisms need to respond to these changes in order to survive. The response of the organism is called its behaviour, which may be simple, e.g. moving away from light, or more complex, e.g. calling and displaying for a mate. A behaviour that contributes to an organism's survival

LINK 2

Species interactions f Communicating f Competition f Mutualism f Exploitation f Breeding behaviour 1. (a) What is a behaviour? (b) In what way is behaviour adaptive? 2. Contrast an orientation behaviour with a timing behaviour

f Nastic responses: Non-directional

Orientation behaviours

Navigation f Sun compass f Magnetic compass f Chemical cues f Landmarks

Timing behaviours

f Kineses: Non-directional

Predictable responses to environmental rhythms

The position of flowers (food sources) is communicated through body movements.

Why Organisms Need To Respond

f Taxes: Directional Plants

Positioning in response to an environmental stimulus Animals

Honeybees orientate towards the light to escape confinement.

and reproductive success (fitness) is called an adaptive behaviour. Behaviours (usually called responses in plants) are subject to natural selection. Those that increase fitness are retained in a population, whereas those that decrease fitness are eventually lost. Some behaviours are so important they are innate, i.e. genetically programmed. They do not require learning. For example a maggot exposed to light will immediately seek lower light levels because this behaviour reduces the risk of being eaten or drying out. The behaviour is not learned and every maggot responds the same way.

Suggest how a behaviour might become innate:

Honeybees are active during the day (diurnal).

f Tropisms: Directional

f Annual, daily, lunar, tidal

Touch is an important stimulus. It may indicate the presence of a threat or something that will give support.

At its simplest, a reaction to a stimulus can be towards (positive) or away (negative) from the stimulus.

Plants are immobile so the ability of roots to grow towards available water sources aids survival. Invertebrates with poor resistance to drying out are found in moist environments.

KNOW

Lamp

1. Identify the prefix for each of the examples to F above:

Positive: towards the stimulus

Gravity allows organisms to orientate themselves vertically. Most animals tend to orientate dorsal ("back") side up and ventral ("belly") side down. In plants, gravity is an important stimulus for the correct orientation of shoots and roots.

A: D: B: E: C: F:

Light can convey information about orientation (up or down) and about the presence of others. Sudden changes in light can indicate movement, which may need to be avoided.

2. Identify the orientation response of the snail to the light:

Stimulus Prefix Touch ThigmoLight PhotoGravity GraviChemicals ChemoWater HydroTemperature Thermo-

ISBN: 978-1-927309-56-8

Types of Stimuli

USDA A CB EFD LINK 1

Detecting changes in temperature helps organisms survive by adjusting physiology or behaviour to their surroundings. An increase in temperature beyond a certain limit indicates the need to find shade.

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eyes detect light. Most animals, being mobile, monitor the environment as they move through it, so sensory receptors are concentrated in the head region. Stimuli are described using prefixes, e.g. photo-. Orientation responses towards or away from the stimulus are identified as positive or negative.

Negative: away from the stimulus

Key Idea : Orientation responses can be categorised according to the type of stimulus eliciting the response. A stimulus is a change in the internal or external environment capable of eliciting a response in an organism. To do this, a stimulus must be detected by sensory receptors, e.g.

Chemicals indicate the presence of substances that may be useful (food) or harmful (poisons) or may indicate the proximity of other individuals.

Method

stimulus

Results Number of squares crossed Trial Light Dark 1 122 15 2 206 68 3 103 57 4 70 59 Mean Results Number of turns Trial Light Dark 1 80 10 2 165 20 3 110 122 4 90 55 Mean

Kinesis

To investigate the effect of a light-dark regime on the orthokinetic behaviour of woodlice.

The woodlouse was again placed in the petri dish under constant light. The experiment was carried out at room temperature as in experiment 1. The number of turns the woodlouse performed in five minutes was recorded. This was repeated four times. The woodlouse was then placed in constant dark. Again the number of turns performed in five minutes was recorded. This was also carried out four times. The results are shown below.

A petri dish was laid out with 1 cm x 1 cm squares. The investigation was carried out at room temperature (about 21°C). A woodlouse was placed in the petri dish under constant light. The number of squares the woodlouse passed over in five minutes was recorded. This was repeated four times. The woodlouse was then placed in constant dark and the number of squares it passed over in five minutes recorded. Again, this was repeated four times. The results are shown below.

Investigatingwoodlicekinesis woodlice humidity of turnings rest Investigation of kinesis in woodlice

Experiment 1

Woodlice are commonly found living in damp conditions under logs or bark. Many of the behavioural responses of woodlice are concerned with retaining moisture. Unlike most other terrestrial arthropods, they lack a waterproof cuticle, so water can diffuse through the exoskeleton, making them vulnerable to drying out. When exposed to low humidity, high temperatures, or high light levels, woodlice show a kinesis response to return them to their preferred, high humidity environment.

Relative

and of kineses can

response external (

Experiment 2

involve directly to are many be the

%Speedoftime at

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Number

orthokinesis rate movement is In klinokinesis rate of related

Method

To investigate the effect of a light-dark regime on the kilinokinetic behaviour of woodlice.

restattimeof%minuteperMillimetreshourperturningsofNumber 7060504030 10015020025030035050 4035302520151050 10 20 30 40 50 60 70 80 90 100 20 From Allott 2001

Key Idea: Kineses are innate locomotory behaviours involving non-directional movements in response to external stimuli. A kinesis (pl. kineses) is a non-directional response to a stimulus in which the speed of movement or the rate of turning is proportional to the stimulus intensity. Kineses do not

Key Kineses are locomotory involving movements pl. a response stimulus in which of movement the proportional to the intensity.

involve orientation directly to the stimulus and are typical of many invertebrates and protozoa. Two main types of kineses can be identified. In an orthokinesis, the rate of movement is dependent on the stimulus intensity. In a klinokinesis, the rate of turning is related to the stimulus intensity.

Kinesis in body lice

In a circular chamber, lice make relatively few turns at their preferred temperature of 30°C, but many random turns at 35°C. This response enables the lice to increase their chances of finding favourable conditions and remaining in them once found.

2. (a) Complete the results tables on the previous page by calculating the mean for each of the experiments.

iii. Largest percentage of time at rest:

1. Use the graph on woodlice at the top of the previous page to answer the following questions:

i. Largest number of turnings per hour:

(b) Which regime (light or dark) does the woodlice appear to prefer?

(d) Explain how increasing the number of turns or the speed of movement increases a woodlice's likelihood of survival when in a unfavourable environment.

(b) Explain the significance of these movements:

30°C

(a) At which relative humidities do the following occur:

Photocopying

ii. Highest speed of movement:

3. (a) Identify the preferred temperature of a body louse:

(b) The response of the body louse is a klinokinesis / orthokinesis (delete one)

Crayfish in hole

E Directional sunlight

Male moths detect pheromones with their large antennae.

B Female moth Male moth

A flying male moth, encountering an odour (pheromone) trail left by a female, will turn and fly upwind until it reaches the female. This behaviour increases the chances of the male moth mating and passing on its genes to the next generation.

Blowfly maggots will turn and move rapidly away from a directional light source. Light usually indicates hot, dry areas and the maggots avoid predators and desiccation (drying out) by avoiding the light.

When confronted with a vertical surface, snails will reorientate themselves so that they climb vertically upwards. The adaptive advantage of this may be to help the snail find food or shelter, or to avoid overly wet surfaces.

Key Idea: A taxis is an innate locomotory behaviour involving directional movements in response to external stimuli. Taxes (sing. taxis) involve orientation and movement in response to a directional stimulus or a gradient in stimulus intensity. Taxes often involve moving the head until the sensory input from both sides is equal (klinotaxis). Many taxes involve a simultaneous response to more than one

stimulus, e.g. fish orientate dorsal (back) side up in response to both light and gravity. Orientation responses are always classed according to whether they are towards the stimulus (positive) or away from it (negative). Simple orientation responses are innate (genetically programmed). More complex orientation responses may involve learning (the behaviour may be modified based on experience).

White fly larvae burrowing into soil.

Spiny lobsters (crayfish) will back into tight crevices so that their body is touching the crevice sides. The antennae may be extended out. This behaviour gives the lobsters greater protection from predators.

Taxes4

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At close range, mosquitoes use the temperature gradient generated by the body heat of a host to locate exposed flesh. This allows the female to find the blood needed for the development of eggs.

Describe the movements of the maggots during the experiment. Include whether the maggots are positively or negatively phototactic and the rate of the movements.

(a) Describe the movements of the nematodes in plates A and B:

Drop of NH4Cl added

(a) A: (d) D: (b) B: (e) E: (c) C:

(b) Name the orientation behaviour shown in plate A:

1973CouncilResearchMedicalWard,S.

1. Distinguish between a kinesis and a taxis:

2. Describe the adaptive value of simple orientation behaviours such as taxes:

4. The diagrams on the right show the movement of nematodes on plates where a salt (NH4Cl) was added (A) and on a plate where no NH4Cl was added (B).

30 +0.7 -0.8

AB Time (s) Distance of maggot 1 from start point (cm) Distance of maggot 2 from start point (cm) Distance of maggot 3 from start point (cm) Distance

40 +0.2

4 from start point (cm) 10 -1.7 -3.7 -5.8

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5. Some students carried out an investigation of the phototactic movements of maggots. They set up a lamp in a darkened room and placed a maggot on grid paper 10 cm from the lamp. They then recorded the distance the maggot had moved every 10 s. Movements towards the lamp were recorded as positive (+) while movements away from the lamp were recorded as negative (-). The investigation was repeated four times. The results are shown below:

3. For each example (A E) on the previous page, describe the orientation response and whether it is positive or negative:

20 -0.5 -0.0

KEY: • Nematodes added of maggot -3.0 +1.8 -1.5 -6.1 -0.2 -1.4 +1.0 -1.0

Pheromones produced by a honey bee queen and her daughters, the workers, maintain the social order of the colony. The pheromone is a blend of unsaturated fatty acids.

1. (a) What is a pheromone?

Communication in ants and other social insects occurs through pheromones. Foraging ants leave a trail along the ground that other ants will follow and reinforce until the food source is depleted. Ants also release alarm substances, which will send other ants in the vicinity into an attack frenzy. These signals dissipate rapidly if not reinforced.

Key Idea: A pheromone is a chemical produced by an animal and released into the external environment where it affects the physiology or behaviour of members of the same species. Pheromones, which are often sex attractants, are common amongst insects and mammals, and commonly relate to reproductive behaviour. Many mammals, including canids and all members of the cat family, use scent marking to

Pheromones in animal communication and orientation

mark territories and advertise their readiness to mate. Other mammals, including rabbits, release a mammary pheromone that triggers nursing behaviour in the young. Pheromones are also used as signalling molecules in social insects such as bees, wasps, and ants. They may be used to mark a scent trail to a food source or to signal alarm. Pheromones are widely used as baits to attract and trap insect pests.

Reptiles also use the VNO to detect chemicals. The flicking of a snake's tongue samples chemicals in the environment and delivers them to the VNO. This behaviour is used to detect prey.

In mammals, pheromones are used to signal sexual receptivity and territory, or to synchronise group behaviour. Pheromone detection relies on the vomeronasal organ (VNO), an area of receptor tissue in the nasal cavity. Mammals use a flehmen response, in which the upper lip is curled up, to better expose the VNO to the chemicals of interest.

AAFCCentre,ResearchCerealofcourtesyPhoto

2. Explain how the response of a male moth to female pheromone is adaptive:

(b) What is the significance of pheromones being species specific?

The feathery antennae of male moths are specialised to detect the pheromone released by females. Males can detect concentrations as low as 2 ppm. They use wind direction to orientate, flying upwind to find the female. The sex attractant property of pheromones is used in traps, which are widely used to trap insect pests in orchards.

3. Explain the role of pheromones in orientation and communication in social insects:

Pheromones5 LINK 4

1. What is migration?

Key Idea: Migration is the long distance movement of individuals from one place to another. The risks and energetic costs of migration are offset by gains made at the destination. Migration is the long distance movement of individuals from one place to another. It usually occurs on a seasonal basis and for a specific purpose, e.g. feeding, breeding, or over-wintering. Many animals move great distances at

2. (a) What are the costs of migration to the migrant?

(b) How is the length of the migration related to energetic cost to the animal?

Codling et al, Ecology, GroupNoNon-social2007movementcollisionavoidancemovement

Increasing group size decreases the time taken to reach a navigational target when the group is moving as a social unit. Non-social groups take longer with increasing size because of the need to avoid others in the group (right).

Flocking birds increase aerodynamic efficiency to each other, saving energy. In schooling fish, individuals in the centre of the school use less effort. Flocking and schooling also provide feeding benefits and reduce the risk of predation along the migration route.

KNOW

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(b) How does this enhance individual survival?

different times of the year or at certain stages in their life cycle. Migratory behaviour is innate but there may be a learned component for repeat migrants. The behaviour is triggered by an environmental cue, e.g. a change of season. Migration carries risk and has a high energetic cost. These disadvantages are offset by the benefits offered by the new environment, e.g. food supplies to support breeding.

In order for migratory behaviour to evolve and be maintained, the advantages of migration must outweigh the disadvantages. Migration is a risky and energy expensive behaviour, and animals must spend a lot of time building energy stores that will fuel the effort. The destination provides enough food or shelter to enhance survival of individuals and their offspring. Although some animals migrate individually, many migrate in large groups (right and bottom).

The energy cost of migration is different for birds, mammals, or other animals. Studies show that for a 100 g animal to travel 1 km a running mammal uses 2400 J, a flying bird uses 640 J and a swimming fish uses just 240 J. One gram of fat gained while feeding before a migration gives the animal about 37 kJ of energy, taking a mammal 15 km, a bird 54 km, and a fish 154 km. The migrations of walking or running animals therefore tend to be much shorter than those of flying or swimming animals.

Group size

3. (a) How does grouping together increase navigational efficiency?

10 Migration6

ISBN: 978-1-927309-56-8

targetreachtotakentimeAverage units)time(arbitrary

Group migration helps navigation by what is called the "many wrongs principle" in which the combining of many inaccurate navigational compasses produces a more accurate single compass. Thus, if an animal navigates by itself with a slightly inaccurate internal compass, or inaccurately interprets environmental cues, it may arrive in the wrong location. In a group, each member can adjust its heading according to the movement of the others, thus an average direction is produced and each member is more likely to arrive at the correct place (right).

Benefits of group migration

Similar to one-way migration but individuals may breed at several locations during their lifetimes. These migrations are apparently directionless, with no set pattern. Each stopover point is a potential breeding site. There may also be temporary non-breeding stopovers for the winter or dry season.

muskrat

Key Idea: Migrations often involve very large distances and usually involve a return journey. They are initiated by the activity of internal clocks or timekeepers in response to environmental cues such as change in daylength. True migrations are those where animals travel from one well-defined region to another, for a specific purpose such

as overwintering, breeding, or seeking food. Some mass movements of animals are not true migrations in that they do not involve a return journey and they are not governed by an internal biological clock. Such movements are best described as dispersals and are typical of species such as the ‘migratory’ locusts of north Africa and Australia.

1. Giving an example, describe the conditions under which nomadic migration behaviour might be necessary:

Animals that move to a winter feeding ground are making one leg of a return migration. The same animals return to their home range in the spring which is where they have their breeding sites. Sometimes they follow different routes on the return journey.

Remigration circuits

homeOriginalrange

Dispersal:

4. Explain the adaptive value of migratory behaviour:

Remigration circuit:

Breedingsite

Pacific salmon Migration Patterns7

2. Which of the above forms of migration would lead to further dispersal of a population? Explain your answer:

Dispersal: one-way migration

3. Describe an environmental cue important in the regular migratory behaviour of a named species:

Some migrations of animals involve a one-way movement. In such cases, the animal does not return to its original home range. This is typical of population dispersal. This often occurs to escape deteriorating habitats and to colonise new ones.

Breedingsite Breedingsite BreedingsiteBreedingsite Breeding site Dr y season or winter site First generationSecondgeneration Feeding stopoverBreedingsiteBreedingsite Non-breedingstopover Breeding site BreedingBreedingsitesiteDryseasonorwintersite

Return migration: caribou

In some populations, the return leg of a migration may have stopovers and may be completed by one or more subsequent generations. In addition to winter or dry season areas, there may be stops at feeding areas by juveniles or adults. Also included are closed circuits where animals die after breeding.

Return migration

Nomadic Inuit Nomadic Bedouin

Nomadic migration

Monarch butterflies have one of the longest of all insect migrations. Five or more generations are needed to complete one migration cycle. In North America, the insects overwinter in mass roosts in southern California or near Mexico City. In spring they migrate north, with some even reaching Canada by late summer, then return south for winter. to 4000 km

Key Idea: Migrations are usually for the purpose of feeding or breeding. True migrations involve a return journey. Migrations come in many forms. Some of the longer, more commonly noted ones are shown below. However, migrations

3000

do not have to be long distances or seasonal. Many marine animals migrate from the deep ocean to the surface daily to feed, this may only be a distance of a few hundred (vertical) metres or less.

3000 km 3000 12,000to km 750 1000tokm 2000

OCEANINDIAN PACIFICOCEAN ATLANTICOCEAN AscensionIsland SargassoSea Examples of Migration8 LINK 7 LINK 10 WEB 8

A number of whale species, including humpback and grey whales, follow an annual migration. In summer, they feed in the krill-rich waters of polar regions. In winter, they move closer to the equator to give birth to young conceived the previous year and to mate again. They seldom feed in transit.

Migratory locusts are found in desert regions of northern and eastern Africa, the Middle East and Australia. Their migration is more strictly a dispersal in response to an expanding population with limited food. The lack of food triggers development of the voracious, migratory form.

Caribou spend the winter feeding in the coniferous forests in central Canada. In the spring, they move north to the tundra of the Barren Lands, within the Arctic circle, a distance of some 1000 km. There they give birth to their calves in the relative safety of the open tundra.

1600

3000 km

A number of shearwater species (including mutton birds) breed in Australia and islands around New Zealand, then migrate northwards with the onset of the southern winter to the north and northeast Pacific. The return journey across the eastern Pacific is assisted directly by the NE trade winds.

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In New Zealand and elsewhere, spiny lobsters periodically make migrations of many hundreds of kilometres. The movement is predominantly against the prevailing current. It is thought to compensate for the long-term downstream movement of the population as planktonic larvae are swept in one direction by the ocean currents.

The European swift is one of 140 bird species that follow one of Europe's migratory routes from northern Spain to Africa. Swifts breed throughout Europe, and migrate to south of the Sahara after breeding. Swifts feed on the wing and the onset of the migration is thought to be triggered by the lack of nutritious airborne insects.

European eels migrate across the northern Atlantic ocean to spawn in the Sargasso Sea off the coast of Florida. The larvae that hatch from the eggs gradually drift back across to Europe, a migration that takes several years. Eventually they enter estuaries and move upriver where they feed, grow and mature.

7000

11,000

PACIFICOCEAN

Green turtles migrate between coastal foraging areas and nesting grounds. They return from the coasts of South America to the beach of their own spawning on Ascension Island to lay eggs.

Polar bears can cover distances of up to 1600 km walking across ice from Alaska, USA to set up winter dens across the Bering Strait in Siberia. km km km to 13,500 km

(a) Migratory locust: (f) Monarch butterfly: (b) Caribou: (g) European swift: (c) Shearwater: (h) Humpback whale: (d) Polar bear: (i) European eels: (e) Green turtle: (j) Spiny lobster:

Migrations are no doubt based in part on the search for food and shelter. As food becomes scarce in winter animals move to new areas in search of food, returning when conditions become more favourable.

2. Describe an adaptive advantage of migration for each of the organisms listed below:

1969/70 1973/741977/78 1993/941981/821985/86 1997/982001/022005/061989/90 162432404856647280-8

Change in centre of abundance in 305 widespread North American birds

Migration is often an adaptive response to seasonal environments, allowing animals to exploit favourable conditions at different times of the year. Migrations probably evolved as a result of seasonal changes in distribution that offered benefits to fitness. However, very little evidence has been uncovered to shed light on how animals such as the Arctic tern came to migrate 70,000 km from one pole to the other and back every year. Some computer models based on the current distribution and migration of North American birds suggest the ancestral populations lived in North America all year round before evolving migrations that took them to the tropics during the Northern Hemisphere winter. The origins of oceanic crossings is still contested. It is possible that some species were migrating before the continents split and drifted apart, but this assumes that the same route has been used for millions of years.

(a) Monarch butterflies: (b) Humpback whale: (c) Spiny lobster:

1. Match up the ten numbered migration routes on the map on the previous page with each of the animals below:

(a) Describe how increases in global temperatures have affected some migratory birds:

(b) Explain how these changes in migratory patterns might affect food availability and survival for these populations:

The origins of migration

3. There is now ample evidence that the distributions and migratory patterns of animals are being affected by rising global temperatures. Northern Hemisphere data show that birds are migrating north to summer feeding grounds up to two weeks earlier and are not migrating as far south in winter. The mean January temperature over the period plotted (right) has increased by ~3.5°C.

Distancemovednorth(km)

During the breeding season, pied stilts can be found in swamps, lagoons, flooded pastureland and open wetlands in both North and South Islands. To overwinter after breeding, they move to the coast with some movement northwards.

Bird Migrations in New Zealand

South Island pied oystercatcher Haematopus ostralegus finschi

Note:

Banded dotterel

Pieddotterelstilt

Himantopus h. leucocephalus

Banded

Anarhynchus

Key Idea: New Zealand has a number of migrant bird species. Some move great distances, according to their needs in the different seasons.

The South Island pied oystercatcher breeds only in the South Island, east of the Southern Alps. With the onset of winter, they migrate to all other parts of the country where they can be found in estuaries and harbours from Stewart Island to Northland. In spring they return to their breeding sites on lake shores, inland rivers and farmland.

1. For each bird species listed below, identify the sites for breeding and overwintering: (a) Wrybill breeding: Wrybill overwintering: (b) Pied stilt breeding: Pied stilt overwintering: (c) SI pied oystercatcher breeding: SI pied oystercatcher overwintering: (d) Banded dotterel breeding: Banded dotterel overwintering: 2. Describe the adaptive advantage of the migrations from breeding areas to overwintering areas: 3. Describe a possible cost to the birds of annual migration:

The wrybill breeds on riverbeds in Canterbury and Otago where nests are made in pebble-lined scrapes in the shingle. In winter, most of the population heads north to feeding grounds at the Firth of Thames, the Manukau and Kaipara Harbours and elsewhere on the coast.

Banded dotterel Charadrius bicinctus

Otago

HarbourParengarenga

Firth of KaiparaManukauThamesHarbourHarbour

Pied stilt Pied stilt Pied stilt LINK 10 LINK 11 WEB 9

South

Canterbury

Banded dotterels breed mostly on lake shores and inland riverbeds (both islands). They also sometimes nest on the slopes of some ranges and inland tussock. In autumn, they migrate in large flocks to wintering places, moving to the coast and north, to the top of the South Island and the north of the North Island, and even to Australia.

Pied stilt

Island pied Wrybilloystercatcher

The movements of four species of migrant waders overwintering at Miranda in the Firth of Thames are shown below. The tidal flats at Miranda offer a rich feeding ground.

Arrows show movements of birds to breeding areas. The arrows are not the only movements of these species in New Zealand.

Wrybill frontalis

mEmS

After two nights After three nights

Experiments have been carried out to investigate the existence of a sun compass and its importance for daytime migrations. Caged birds were placed in circular enclosures with four windows. Mirrors were used to alter the angle at which light entered the enclosures. At migration time, in natural conditions, these birds clearly showed a preferred flight direction (A). When mirrors bent the Sun's rays through 90°, the birds turned their preferred direction (B and C).

Sky rotated 90° Sky obscured North North

Migratory Navigation in Birds10

Sun compass

BlindBlind

Sunlight Sunlight Sunlight

(b) Star compass:

An experiment to investigate the existence of a magnetic compass in migratory birds used magnetic coils to mimic the Earth’s magnetic field. The birds detect magnetic north, the direction of their spring migration. When the magnetic field was twisted so that north was in the east-southeast position, the birds kept their original path for the first two nights. By the third night, they had detected the change and altered their path accordingly.

Mirror Mirror

mNmS

Star compass

mEmS

mNmS

Real sky North

Original orientation mEmW mN mW mN mW

Sky rotated 90° Sky obscured North North

mNmS

Key Idea: Migratory birds use a wide range of environmental cues to navigate accurately and determine their destination. Navigation is the process by which an animal uses various cues to determine its position in reference to a goal. Migrating

Mirror Mirror

Sky rotated 90° Sky obscured North North

After two nights After three nights

(a) Sun compass:

mEmS

Original orientation mEmW mN mW mN mW

Mirror Mirror

birds must know their flight direction and when they have reached their destination (goal). Cues include star and solar cues, landscape features, wind direction, polarised light, magnetic and gravitational field information, and smell.

Sunlight Sunlight Sunlight

Original orientation mEmW mN mW mN mW

BlindBlind

A B C

Real sky North

LINK 11 WEB 10

Real sky North

mEmS

BlindBlind

mEmS

1. The experiments above investigated three possible compass mechanisms used by migratory birds to navigation. Summarise the results of each experiment, and state whether or not the experiment provided evidence that the birds were using the compass mechanism:

mEmS

Magnetic compass

An experiment to investigate the use of star positions in the night sky used an ink pad at the base of a cone of blotting paper. Nocturnal migrants flutter in their preferred direction of travel as the amount of ink shows. In a planetarium that projected the real sky, indigo buntings located the Pole Star and used it to find north, the direction of their spring migration. When the sky in the planetarium was rotated 90° counter-clockwise the birds altered their direction accordingly. Simulating a cloudy night, the obscured sky confused the birds.

4. Study the information on the blackcap migrations above and the answer the following:

(b) How is this different to the experienced birds?

Navigation and migration in starlings and blackcaps

The juveniles, which had not migrated before, flew to Spain. The more experienced birds reached their winter homes in France, Britain, and Ireland.

Blackcap migration

European starling migration

2. Birds that use a sun compass to navigate rely on the position of the Sun in the sky as a reference point to determine north. Because the earth rotates on its axis once a day, the position of the Sun in the sky is constantly changing. Describe an essential mechanism that the birds must have in order to make use of this type of compass:

(a) What do you notice about the migration pattern of the hybrid blackcaps?

(b) What does this tell you about the origin of the migration pattern?

Normaldirectionofmigration JuvenilesAdults TheSwitzerlandBirdsmovedNetherlandsbyplane

An experiment with starlings investigated the roles of genetics and experience in navigating during migration. Birds caught in the autumn leg of their migration were captured in the Netherlands and taken to Switzerland and released.

Blackcaps are divided in their migration paths. Birds breeding in eastern Europe fly via Turkey to eastern Africa. Those from western Europe fly across the Strait of Gibralta to north Africa. In an experiment to test the genetic component of their migratory navigation, birds from both populations were bred together. The hybrids flew south on a course taking them over the Alps and the widest part of the Mediterranean.

Blackcap

3. Study the information on the European starling migrations above and the answer the following:

Direction of travel hybridsof

(a) What direction did the juvenile starlings fly once they were relocated?

areawinteringNormal

birdsEuropeanEast birdsEuropeanWest

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1. On the map above, draw labelled arrows from New Zealand and Australia to the islands mentioned for each cuckoo.

2. Use the scale on the diagram to determine the maximum distance covered by each cuckoo species in their migration from New Zealand to the islands in the South Pacific. Check your measurement on nz.mapometer.com if you wish.

Chrysococcyx lucidus

Australia Zealand IslandsCaroline Islands

grounds Chatham

They both have their breeding season in New Zealand or Australia during the southern summer, parasitising the nests of smaller songbirds such as warblers and yellowheads, which breed at the same time. They migrate north in autumn to wintering grounds in the tropical Pacific.

(a) Long-tailed cuckoo: km

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3. What method(s) of navigation would the birds be likely to use during this migration. Explain your answer:

Key Idea: The shining cuckoo and long-tailed cuckoo are land birds that make annual migrations between temperate breeding grounds and more tropical overwintering grounds. The long-tailed cuckoo and the shining cuckoo are New Zealand’s only forest birds that migrate out of the country.

Fiji Sunda

Long-tailed cuckoo Eudynamys taitensis

Breeds in New Zealand parasitising the nests of whiteheads and yellowheads. Migrates to islands of the tropical Pacific including the Caroline Is., Marshall Is., Marquesas Is., and Tubai Is. The main wintering area is between Fiji and Tahiti to the east.

Shining cuckoo

(b) Shining cuckoo (New Zealand population): km

New

Called the bronze shining cuckoo in Australia. The eastern portion of the Australian population migrates to New Guinea while those from south-western Australia migrate to the Sunda Islands in Indonesia.

NePapuawGuinea Bismark ArchipelagoSolomonIslands Tubai Is Marquesas Marshall

IslandsBreeding Islands

Called the shining cuckoo or Pipiwharauroa in New Zealand. Breed in New Zealand (including the Chatham Islands) where the birds parasitise the second laid clutches of warblers The birds migrate to the Solomon Islands and the Bismark archipelago.

4. Describe the adaptive advantages to these birds of making such a risky and demanding long distance migration:

Cuckoo Migrations11 1000 km LINK 10 WEB 11

Shining cuckoo

If the bee moves directly up the comb, it means the food source is directly in line with the Sun.

50° right turnedAngle (°)antby Polariser angle (°)120120 90 90 30 606030 Direction of polarised light Direction of travel by ants 3.0CCTørrissenChristianBjørnSaharan silver ant (Cataglyphis bombycina) LINK 13 WEB 12

An experiment investigated the effect of polarised light on navigation in Cataglyphis ants by placing a food source at a regular location near a nest. The ants learned its location and moved directly to the food source each foraging trip. A polarising screen was then placed over the ant trail. Rotating the screen caused the ants to follow a path at an angle equal to that which the polarised screen was rotated (right).

The direction of travel by the ants is equal to the angle of rotation of the polarised screen.

Other bees will be in close attendance to monitor the dance and learn the location of the new food source.

The vertical axis of the honey comb equals the current position of the Sun.

Training under clear blue sky Polariser

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current position of the Sun. In the waggle dance, they adjust their dance to account for the changing direction of the Sun. Animals that see polarised light can detect the plane of light in the sky even if the Sun itself is obscured from view.

Key Idea: The position of the Sun is an important navigational cue for many animals including insects such as bees and ants. Honeybees navigate using a sun compass, so honeybees communicate the direction and distance to food relative to the

The duration and speed of the waggle indicates how close the food source is. A long dance indicates a more distant food source. A faster waggle indicates a richer food source.

In bee hives, the combs hang vertically. Position of the Sun

Movements of the bee to the left and right of the vertical axis give the angle of the food relative to the Sun. In this case the food source is 40° to the right of the Sun.

Food source

40° Sun Compass Navigation12 The honeybee waggle dance

left

Polarised light navigation in ants in place Polariser 50° Polariser

Bees communicate the direction and distance of the food source through the waggle dance (above). If food is located directly in line with the Sun, the communicator (bee in the blue circle) demonstrates it by running directly up the comb. To direct bees to food located either side of the Sun, the bee introduces the corresponding angle to the right or left of the upward direction into the dance. Waggle dancing bees that have been in the hive for an extended period adjust the angles of their dance to account for the changing direction of the Sun. This means directions to the food source are still correct even though the Sun has changed positions.

Foraging trip trip Food source source

A B C

Foraging under clear blue sky

7. Explain why animals that can detect polarised light (e.g. ants and bees) can continue to navigate accurately when the Sun is obscured from view (e.g. a partially cloudy day).

Polarised screen placed over ant and rotated 45° to the left.

6. Diagram A below shows the foraging and return trips of a Cataglyphis ant under blue sky. On diagrams B and C draw in the line of the return trip of the ant when a polarised screen is placed over the ant: Nest Food source

3. Explain how the bee compensates for the time it takes between finding the food and delivering its message to the hive:

Foraging trip

1. Name the environmental reference used by honey bees to orientate for navigation:

Return

4. What environmental cue do Cataglyphis ants use to navigate?

2. (a) Explain how a honey bee communicates the location of a food source to other honey bees in the nest: (b) Explain the adaptive value of this behaviour:

5. What was the effect of rotating the plane of polarised light on the ants' ability to navigate to the food source?

Foraging trip

Nest Food

Nest

Polarised screen placed over ant and rotated 25° to the right.

although navigation is involved in both behaviours. Homing behaviour often relies on the recognition of familiar landmarks, especially where the distances involved are relatively short. Navigation, often assisted by the use of trail pheromones, is also involved in the foraging behaviour of many insects.

While a female wasp was in the burrow, Tinbergen placed a circle of pine cones around the nest entrance. When she emerged, the wasp reacted by carrying out a wavering orientation flight before flying off.

Philanthus triangulum

1. Why did moving the pine cones around the wasp nest result to the wasp being unable to find the nest?

Homing in ants

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Homing Behaviour in Insects captured

13 Nest Food source ForagingjourneyReturntrip Nest Ant

Step 1: Orientation flight

at food source

Step 2: Return flight

The beewolf (Philanthus) digs a nest in sand. It is a predator of bees and captures and paralyses bees as food for its larvae during development. The paralysed bee is taken back to the wasp's underground nest, where the wasp lays its eggs in the still living body. In a well-known experiment to test the homing behaviour of this wasp, a scientist named Tinbergen, carried out a 2-step experiment. (After Tinbergen, 1951. The Study of Instinct. Oxford University Press, London)

Wasp Wasp Nest conesPine PreyconesPineNest(bee)

Key Idea: Homing is the ability of an animal to return to its home site after being displaced and it involves navigation. In many insects, homing is important in increasing foraging efficiency because it reduces energy expenditure. Homing (returning to a home site) is distinct from migration,

During her absence, the pine cones were moved away from the burrow leading to the nest. Returning to the nest with prey, the wasp orientated to the circle of pine cones, not the nest entrance.

Ant

Cataglyphis desert ants use polarised light to navigate while foraging, often pausing and turning 360° to apparently note the position of the Sun and plane of light. When they discover a food source, they return directly to the nest as shown right. This ability to determine the direction to the nest reduces travel time when returning to the nest, making foraging more efficient.

tripForaging released at this point

Homing and navigation in wasps

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Beewolf

3.0ccAlvesgaspar

Cataglyphis ants collect a beetle

2. (a) After a foraging trip, a Cataglyphis ant was displaced to another point some distance away. On the diagram shown right, draw in a line indicating the direction the ant travelled when released: (b) Explain why the ant moved in the direction you drew:

Highway6

Some spawning occurs in the upper reaches of the Paringa River during years of high abundance.

Some incidence of straying by salmon into the Ohinemaka drainage.

2. Salmon may be removed (as eggs or fry) from their stream of origin and farm reared before being released to grow at sea. These fish generally fail to return to their natural headwaters to breed. Suggest why these fish do not return:

(b) Using

sea where they grow to maturity. When ready to spawn, they return to the river they left as juveniles. Travelling hundreds of kilometres in the open ocean, they locate their home river and swim upstream to spawn in the same tributary in which they were hatched. Their navigation from the open ocean may involve using the Earth’s magnetic field or polarised light. Once close to their homeland coast, they rely on smell to detect the unique odour of their home river.

Key Idea: King (chinook) salmon migrate as adults from the ocean to headwaters to spawn, possibly using magnetic fields, polarised light, and scent to help navigate to the river in which they were spawned.

salmon use

Immature salmon spend varying periods (up to 3+ years) in Lake Paringa before completing the marine phase of their life cycle. Eventually the young fish migrate to the Tasman Sea as smolts.

Principal spawningsalmonareas.

Salmon moving upstream to spawn congregate in the lake off the Windbag River mouth while developing to sexual maturity.

Salmon enter the mouth of the Paringa River and move into Lake Paringa via the Hall River.

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Tasman Sea Highway 6ToHaast ToHokitika kindly supplied by Dick Hutchinson, Dept. of Conservation)

King salmon (Oncorhynchus tshawytscha) are anadromous, meaning they migrate from the sea to fresh water to spawn. Salmon possess one of the most remarkable homing instincts of any animal. Young fish travel from the river of their birth to

1. (a) Describe the mechanism to return to the stream where they hatched: the this method of navigation is not foolproof: the natal stream to spawn:

map above, describe the evidence indicating that

OhinemakaRiver

Lake Paringa

Out-migrant salmon live and grow to maturity in coastal water to the north and south of Paringa drainage.

Homing in Salmon

King salmon (Oncorhynchus tshawytscha) occupy the Paringa River drainage on the west coast of the South Island. The Lake Paringa salmon stock includes both landlocked (nonmigrating) and anadromous individuals.

ParingaRiverRiHallver WindbagRiver

Area enlarged on map to the right

(Information

Plants are capable of quite rapid responses. Examples include the closing of stomata in response to water loss (below), opening and closing of flowers in response to temperature, and nastic responses. These responses may follow a circadian rhythm and are protective in that they reduce the plant’s exposure to abiotic stress or grazing pressure.

Although plants are rooted in the ground, they can still compete with other plants to gain access to resources. Some plants produce chemicals that inhibit the growth of neighbouring plants. Such chemical inhibition is called allelopathy. Plants also compete for light and may grow aggressively to shade out slower growing competitors.

(a) Low soil water:

Tropisms are growth responses made by plants to directional external stimuli, where the direction of the stimulus determines the direction of the growth response. A tropism may be positive (towards the stimulus), or negative (away from the stimulus). Common stimuli for plants include light, gravity, touch, and chemicals

mainly through changes in patterns of growth. These responses may involve relatively sudden physiological changes, as in flowering, or a steady growth response, such as a tropism. Many of these responses involve annual, seasonal, or circadian (daily) rhythms.

Rapid responses to external stimuli

Plants use seasonal changes (such as falling temperatures or decreasing daylength) as cues for starting or ending particular life cycle stages. Such changes are mediated by plant growth factors, such as phytochrome and gibberellin, and enable the plant to avoid conditions unfavourable to growth or survival. Examples include flowering, dormancy and germination, and leaf fall.

ISBN: 978-1-927309-56-8

StanShebscc30

Tropisms

Plant Responses15

Plant responses to herbivory

(d) Low air temperatures at night:

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Life cycle responses

1. Identify the stimuli plants typically respond to:

2. Describe the adaptive advantage of a plant responding appropriately to the environment:

Plant competition and allelopathy

(b) Falling autumn air temperatures:

3. Describe one adaptive response of plants to each of the following stressors in the environment:

Many plant species have responded to grazing or browsing pressure with evolutionary adaptations enabling them to survive cropping or deter browsers. Examples include rapid growth to counteract the constant loss of biomass (grasses), sharp spines or thorns to deter browsers (acacias, cacti), or toxins in the leaf tissues (eucalyptus).

KNOW

Key Idea: Plants generally respond to their environment by growing to or away from a stimulus or by responding in a way that affects some physiological process. Even though most plants are firmly rooted in the ground, they can still respond to changes in their external environment,

Roots(e) respond positively to the Earth's gravitational pull, and curve downward after emerging through the seed coat.

Thale cress bending to the light

2. Describe the adaptive value of the following tropisms:

(d) Positive chemotropism in pollen grains:

away from the direction of the Earth's gravitational pull. Coleoptiles (the sheath surrounding the young grass shoot) show the same response.

Growth(c) response to water. Roots are influenced primarily by gravity but will also grow towards water.

(b) Positive phototropism in coleoptiles:

Growth(f) responses to touch or pressure. Tendrils (modified leaves) have a positive coiling response stimulated by touch.

1. Identify each of the plant tropisms described in (a)-(f) above. State whether the response is positive or negative.

Key Idea: Tropisms are directional growth responses to external stimuli. They may be positive (towards a stimulus) or negative (away from a stimulus).

growth response. Tropisms are identified according to the stimulus involved, e.g. photo- (light), gravi- (gravity), hydro(water), and are identified as positive (towards the stimulus) or negative (away from the stimulus). Tropisms act to position the plant in the most favourable growth

Tendrilenvironment.wrappingaroundtwig

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(a) Positive gravitropism in roots:

3. Explain the adaptive value of a tropism:

Germinatingpollen

Tropisms

PetersKristian

A(a)positive growth response to a chemical stimulus. Example: Pollen tubes grow towards a chemical, possibly calcium ions, released by the ovule of the flower.

Tropisms are plant growth responses to external stimuli, in which the stimulus direction determines the direction of the

Plant growth responses are adaptive in that they position the plant in a suitable growing environment, within the limits of the position in which it germinated. The responses to stimuli reinforce the appropriate growth behaviour, e.g. roots grow towards gravity and away from the light.

Growth(d) responses to light, particularly directional light. Coleoptiles, young stems, and some leaves show a positiveresponse.(b)Stems,grow

Root mass in a hydroponically grown plant

More light

Draw your cells here:

Point A?

2. Light excluded from shoot tip: When a tin-foil cap is placed over the top of the shoot tip, light is prevented from reaching the shoot tip. When growing under these conditions, the direction of growth does not change towards the light source, but grows straight up. State what conclusion you can come to about the source and activity of the hormone that controls the growth response:

Foil cap ofshootGrowingplant

24 LINK 16

(b) What is the name of this growth response?

(e) In the rectangle on the right, draw a diagram of the cells as they appear across the stem from point A to B.

ISBN: 978-1-927309-56-8

1. Directional light: A pot plant is exposed to direct sunlight near a window and as it grows, the shoot tip turns in the direction of the Sun. When the plant was rotated, it adjusted by growing towards the Sun in the new direction.

Directional sunlight

(d) Which side (A or B) would have the highest hormone concentration and why?

Less light

Directional sunlight ofshootGrowingplant

AB Investigating Phototropism17

(a) What hormone regulates this growth response?

because coleoptiles are different to stems. However their conclusions have been shown to be valid. Auxins (a group of plant hormones) promote cell elongation and are inactivated by light. Thus, when a stem is exposed to directional light, auxin becomes unequally distributed either side of the stem. The stem responds to the unequal auxin concentration by differential growth, i.e. it bends. The mechanisms behind this response are now well understood.

Plant A:

Shoot grows in the direction of sunlight

Point B?

Photocopying Prohibited

DirectionalofGrowingsunlightshootplant

KNOW

Key Idea: Experimental evidence supports the hypothesis that auxin is responsible for tropic responses in stems. Phototropism in plants was linked to a growth promoting substance as early as the 1920s. Early experiments investigating phototropism in severed coleoptiles provided evidence for the hypothesis that the plant hormone auxin was responsible for tropic responses in stems. These experiments (outlined below) have been criticised as being too simplistic

3. Cutting into the transport system: Two identical plants were placed side-by-side and subjected to the same directional light source. Razor blades were cut half-way into the stem, thereby interfering with the transport system of the stem. Plant A had the cut on the same side as the light source, while Plant B was cut on the shaded side. Predict the growth responses of:

A B

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Plant B:

Razor blade left in cut

In a horizontally placed seedling, auxin moves to the lower side in stems and roots. The stem tip grows upwards and the root tip grows down. Root elongation is inhibited by the same level of auxin that stimulates stem growth (graph left). The higher auxin levels on the lower surface cause growth inhibition there. The longest cells are then on the upper surface and the root turns down.

shootHorizontaltip Agar

The basis of auxin’s proposed role in gravitropism is outlined below. The mechanism is appealing in its simplicity but has been widely criticised because of the use of coleoptiles. The coleoptile (the sheath surrounding the young grass shoot) is a specialised, short-lived structure and is probably not representative of plant tissues generally.

The role of auxins in gravitropic responses

2. (a) From the graph above, state the auxin concentration at which root growth becomes inhibited:

This simple explanation for gravitropism has been criticised because the concentrations of auxins measured in the upper and lower surfaces of horizontal stems and roots are too small to account for the growth movements observed. Other studies indicate that growth inhibitors may interact with auxin in gravitropic responses. block

33% auxin Barrier

Gravity

3. Explain why the gravitropic response in stems or roots is important to the survival of a seedling:

67% auxin

Agar

(a) Stems:

ExperimentsRoots:on

Gravityity block

1. Explain the mechanism proposed for the role of auxin in the gravitropic response in: (a) Shoots (stems):

(b)

isolated shoot tips provide evidence that gravitropism (like phototropism) is due to different growth rates of upper and lower sides of the stem or root in response to the redistribution of auxin. In a horizontally placed shoot tip (right), more auxin accumulates on the lower side than on the upper side. In stems, this causes elongation of the cells on the lower surface and the stem tip turns up. The root grows down because root elongation is inhibited by high levels of auxin on the lower surface (graph below).

Key Idea: Auxin appears to have a role in the gravitropic responses of roots, but its effect may depend on the presence of other plant growth regulators.

The importance of auxin as a plant growth regulator, as well as its widespread occurrence in plants, led to it being proposed as the primary regulator in the gravitropic response.

(b) State the response of stem at this concentration:

(b) Roots:

A horizontally placed stem tip grows upwards. This is negative gravitropism

Auxin moves to the lower side. The cells on the lower side elongate in response to auxin and the stem turns upward.

A horizontally placed root (radicle) tip grows downwards. This is positive gravitropism

Increasing concentration of auxin (mg lL-1 , log10 scale) 10-5 Stems Roots 100responseingainorofElongation (percent)auxinto InhibitionInhibitionPromotionPromotion 10310-3 10-1 101 1500 The growthgrowththatconcentrationsauxinenhancesteminhibittheofroots

Auxin concentration and root growth

Investigating Gravitropism18

(d) Predict the result after six more days growth if the students rotated the seedling in photo 3 90° clockwise. Draw your answer in the space right:

Photo 2: After photo 1 was taken, the cardboard was rotated 90°.

(b) Describe what happened to the root when the students rotated the cardboard 90°:

Root beginning to bend down 3

Key Idea: The effect of gravity on the direction of root growth can be easily studied using sprout seeds. The direction of root growth will change if the seedling's orientation is altered. The experiment described below is a simple but effective

way in which to investigate gravitropism in seedlings. Using the information below, analyse results and draw conclusions about the effect of gravity on the directional growth of seedling roots.

Day 11 LINK 18

The aim

Investigating Gravitropism in Seeds19

To investigate the effect of gravity on the direction of root growth in seedlings.

The students took photographs to record changes in growth during the course of the experiment. One seedling at day 5 and 11 is shown below.

Hypothesis

A damp kitchen paper towel was folded and placed inside a clear plastic sandwich bag. Two sprout seeds were soaked in water for five minutes and then placed in the centre of the paper towel. The bag was sealed. The plastic bag was then placed on a piece of cardboard which was slightly larger than the plastic bag. The plastic bag was stretched tightly so the plastic held the seeds in place, and secured with staples to the cardboard.

Results

(b) In what direction did the shoot grow after rotation 90° (photo 3)?

Method

Roots will always grow towards the Earth’s gravitational pull, even when the seedling's orientation is changed.

Photo 1: This photo was 5 five days after the seed began to germinate.

Shoot beginning Day 5 Day

1. (a) What direction did the root first begin to grow in?

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Photo 3: This photo was taken 6 days after the seed was rotated 90°. Root 5, rotated 90° clockwise

Daily observations and photographs were made of the root length and direction throughout the duration of the experiment. Photos of one seedling from days 5 and 11 are shown right.

(a) In what direction did the shoot grow at first?

The cardboard was placed upright against a wall. Once the first root from each seed reached 2 cm long, the cardboard was turned 90° degrees.

21 Shoot

KNOW

2. During the course of the experiment a shoot developed.

f The sensitive plant (Mimosa pudica) has long leaves composed of small leaflets. When a leaf is touched, it collapses and its leaflets fold together. Strong disturbances cause the entire leaf to droop from its base. This response takes only a few seconds and is caused by a rapid loss of turgor pressure from the cells at the bases of the leaves and leaflets.

f The adaptive value of these responses is uncertain but may relate to deterring browsers or reducing water loss during high winds.

PulvinustissueVascular

Disturbed leaf

LeafletLeaf

Nastic Responses

Key Idea: Nastic responses are plant responses in which the direction of the plant response is independent of the stimulus direction. They are reversible and often rapid movements. Nastic responses in plants are independent of the stimulus direction and may involve quite rapid, reversible movements, often resulting from localised changes in turgor.

Nastic responses can occur in response to temperature (thermonasty), light (photonasty), or touch (thigmonasty). Plant 'sleep movements', in which flowers close or leaves droop at night, are specialised diurnal photonasties. The mechanisms involved in Mimosa's thigmonasty (below) are also responsible for the leaf movements of the Venus flytrap.

Cells on the lower surface lose turgor and the leaf collapses.

Thin walled parenchyma cells specialised as motor cells.

This mechanism also operates at the leaflet bases, except that the cells on the upper surface of the pulvinus lose turgor, and the individual leaflets fold up, rather than down (left).

leaf

Leaf Leaflets

The leaves of Mimosa have joint-like thickenings, the pulvini (sing pulvinus) at the bases of the petioles and at the bases of each leaflet. The pulvini contain specialised motor cells, which are involved in the rapid leaf movements.

Unstimulated

f The message that the plant has been disturbed is passed quickly around the plant by electrical signals (changes in membrane potential) not by plant hormones (as occurs in tropisms). The response can be likened to the nerve impulses of animals, but it is much slower. After the disturbance is removed, turgor is restored to the cells, and the leaflets slowly return to their normal state.

Movements of the sensitive Mimosa plant

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RCNRCN

K+ H2O K+

Epidermis Epidermis

Leaflet Leaf axis Leaflet base

Cells on the upper and lower surfaces are turgid

When disturbed, a change in membrane potential of the leaf cells is transmitted to the cells of the pulvinus. These cells respond by actively pumping potassium ions out of the cytoplasm (see inset above). Water follows osmotically and there is a sudden loss of turgor.

Sundews also show a thigmonastic response. An insect landing on a leaf quickly becomes trapped in the sticky hairs. The hairs fold around the insect and in some species the leaf may curl over, completely enclosing the insect.

1. Identify the type of nasty involved in each of the following examples:

(b) Explain how the movements of the Mimosa pudica help its survival:

(b) Describe how carnivory benefits this plant in its habitat:

Orikrin1998

Venus flytrap (Dionaea)

3. (a) Describe the basic mechanism behind the sudden leaf movements in Mimosa:

5. (a) How does the Venus flytrap ensure the closing of the trap is not falsely triggered?

Many plants show movements in relation to light and dark. Oxalis (right) spreads it leaves out during the day to capture sunlight. During the night the leaves are lowered and bend slightly along the midline. This helps to prevent dew accumulating on the leaf and minimises the risk of damage while the leaf is not being used to capture light. Day Night

When an insect touches the hairs on a leaf of a Venus flytrap (right), the two lobes of the leaf snap shut, trapping the insect. Once the insect has been digested, the empty leaves reopen. The hairs on the leaf must be touched twice in quick succession for the leaf to close. This means false alarms, such as a twig falling onto the leaf, do not set it off.

(a) Opening and closing of tulip flowers to changes in air temperature:

Carnivory has evolved independently nine times in five different orders of plants.

Sundew (Drosera)

Sleep movements in plants

4. How could the sleep movements of plants (lowering the leaves at night) benefit a plant?

Thigmonastic responses in carnivorous plants

Lazaregagnidze

Some small, specialised plants obtain most of their nitrogen (but not their energy) from trapping and digesting small animals such as insects. This allows them to grow in nutrient-poor (particular low nitrogen), high light environments, such as acidic bogs and rocky outcrops.

2. How is a nastic response different from a tropism?

(b) Opening of evening-primrose flowers at dusk:

Summarise what you know about this topic so far under the headings provided. You can draw diagrams or mind maps, or write short notes to organise your thoughts in preparation for the NCEA style essay question that follows. Use the points in the introduction and the hints provided to help you:

Tropisms

HINT: Include definitions and explain the mechanisms of phototropism and gravitropism.

HINT: Be sure to include definitions, adaptive value, and examples of both types of responses.

Taxes and kineses

Homing and migration

HINT: Include a definition as well as reference to navigation and the benefits and costs of migration.

You Know So Far: Orientation in Space21

Nastic responses

WhatProhibited

HINT: How do nastic responses differ from tropisms? What is their purpose?

• Explain some of the methods it may be using to navigate

0.10.20.30.40.50.60.70.80.9-60-40-2020400 J JA A PacificNorth PacificSouth Breed BreedMigration PositionPositionofbirds of

The sooty shearwater (Puffinus griseus, muttonbird or titi) migrates up to 65,000 km. It is one of the longest migrations of any animal. From October to March, sooty shearwaters raise their chicks (which takes about 100 days) on oceanic islands around the sub-Antarctic region of New Zealand. During the breeding season, tens of thousands of chicks are taken by commercial hunters. From April to May, they begin migrating to specific areas of the sub-Arctic, arriving from June to July for the Northern Hemisphere summer. The sooty shearwater is often seen behind fishing trawlers picking up scraps.

2. Suggest why the sooty shearwater begins its return journey in October when North Pacific Ocean productivity is greater than South Pacific Ocean productivity. oceansofProductivity F M M O 60 birds vs ocean productivity winds of Pacific OceanFlight of shearwaters

Trade

NCEA Style Question: Migration

Sooty shearwater

N D J

mC(g-2d-1) J

• Suggest reasons why its numbers have been dropping

two sooty

Month Latitude

• Explain why it would undertake such a long migration

1. Discuss the migratory behaviour of the sooty shearwater as it travels from sub-Antarctic waters to sub-Arctic waters (you may use extra paper if needed).

(a) Identify the plant hormone responsible for etiolation: (b) Explain how etiolation occurs and discuss how it acts a survival mechanism for plants (you may use more paper if required):

3.0CCChapChriwick

Style Question: Plant Responses

1. Etiolation is a condition in plants caused by growth in the absence of light. The stem becomes long and thin, the leaves are yellow in colour, and the cells are elongated with weak cell walls. The photo below shows an etiolated plant on the left, next to a plant grown in normal sunlight on the right.

B The process of using environmental cues to determine position in reference to a goal.

D A plant growth response to a directional external stimulus.

E The long distance movement of animals from one region to another, usually seasonally

F A non-directional animal orientation response in which the speed or movement or rate of turning is proportional to stimulus intensity

tropismtaxisnavigationmigrationkinesisdispersal3.0CCTangopaso

(b) What distinguishes this behaviour from a migration?

1. (a) What is the name given to a plant growth response to directional light?

(b) What is the name given to a plant growth response to gravity?

4. Match the following words with their definitions:

C A one-way movement away from an area in response to environmental change

5. The photo (left) shows swarming behaviour in locusts:

(d) How is this response adaptive?

(d) What plant hormone is principally responsible for the phototropic effect?

(a) What responses are being shown by the orchid in the photo (left):

(b) What is the stimulus involved?

(a) What event is likely to be occurring here?

2. (a) The honeybee waggle dance communicates the location of a food source based on: star compass navigation / local geography and landmarks / sun compass navigation (delete two)

TEST 32

KEY TERMS AND IDEAS: Orientation in Space

A Animal orientation and movement in response to a directional stimulus

(b) The honeybee round dance communicates that a food source is close by. Does it also communicate direction? Y / N

(a) Earth orbiting the Sun: Cue:

Photocopying

2. Organisms living well away from the equator (i.e. closer to the North or South pole) experience different lengths of daylight during different seasons. Describe the position of the Earth’s South pole (southern axis) during New Zealand’s:

Cosmic forces, such as the movement of the Moon around the Earth and the Earth and planets around the Sun generate

(b) Summer months:

25 summerhemisphereSouthernsolstice winterhemisphereSouthernsolstice June 21December 21 EARTH SUN MOON winterhemisphereNorthernsolstice summerhemisphereNorthernsolstice

predictable environmental cycles such as day and night and the seasons. These cycles provide cues that enable many organisms to time important events in their lives, such as foraging activity, breeding, and migration. The tidal cycle is not shown on the diagram below, but involves the gravitational pull of the moon as well as centrifugal forces on the oceans.

The Moon's orbit around the Earth produces tides. High tides are slightly more than 12 hours apart (as are low tides). This regularity synchronises tidal rhythms in marine organisms. The time between full moons is 29.5 days and many organisms synchronise rhythms with this lunar cycle.

Earth day

Earth's axis

The Earth does not spin upright; it has a 23.5° tilt. This tilt always faces the same way, resulting in seasonal changes in sunlight and weather.

Key Idea: The motions of the Earth, Moon, and Sun result in complex, interdependent cycles, creating environmental changes that range from short term (a few hours) to long term (many hundreds of days).

Prohibited 33

1. For each of the following astronomical cycles, identify the environmental cue they produce and the period of the cycle:

(a) Winter months:

Astronomical

Solar year

Period:

The journey around the Sun takes 365.25 days. The regularity of this motion acting jointly with the angle of the Earth's axis produces the regular changes in the seasons.

3. Environmental cues often take the form of predictable cycles. Predict the role of environmental cues in biological rhythms, and how they might influence plant and animal responses: Cycles

LINK 28

Every 24 hours, the Earth completes one rotation with respect to the Sun. This rotation produces the daily light-dark cycle experienced on Earth.

Lunar month

(b) Moon orbiting the Earth: Cue: Period:

(endogenous rhythms) will continue even in the absence of environmental cues, although the period (duration) of the rhythm may be slightly different to the environmental rhythm. Biological clocks have an adaptive function, such as helping anticipate environmental changes and preparing the body for the activities that will predictably follow.

A biological clock is an endogenous (internal) timing system that helps to control the physiological responses and activities of an organism. Rhythms established by the biological clock

Synchronisation of migration, reproduction, or social activities. Animals congregate at breeding grounds at the same time of year.

Honeybee

Gannets Clocks

Biological

Prediction of and preparation for events in the environment (e.g. storing food reserves as fat for periods of torpor or hibernation).

The location of the biological clock varies between organisms. In birds, reptiles, and amphibians it is located in the pineal gland (in the brain). In insects each cell has its own biological clock. In mammals the biological clock is located in the hypothalamus.

For most humans, the biological clock runs at about a 25½ hour day. To keep it synchronised with the 24 hour-day cycle it needs to be reset each day, reacting to outside stimuli such as light and dark and meal times. The clock is made up of a collection of cells in the hypothalamus, called the suprachiasmatic nucleus (SCN), just behind the eyes. Light from the eyes stimulates the nerve pathways to the SCN and regulates its activity.

Functions of the biological clock

Once exposed to light, the suprachiasmatic nucleus (SCN) communicates with the hypothalamus and pineal gland to promote wakefulness (e.g. by raising body temperature, releasing stimulating hormones, and suppressing melatonin production.

Key Idea: A biological clock is the endogenous timing system an organism uses to synchronise its activities with the external environment.

Eye

Photocopying Prohibited

Where is the biological clock located?

The pineal gland secretes the sleep-inducing hormone melatonin in the dark. Melatonin production is suppressed by bright light.

(b)(a)

(b) What is the main stimulus that helps synchronise the biological clock with the environment?

The biological clock helps to control internal rhythms such as heart activity, hormone secretion, blood pressure, oxygen consumption, and metabolic rate. When the rhythms controlled by the biological clock become out-of-sync with the environment various short or long term disorders can occur, e.g. jet lag. Some functions of the biological clock are described below:

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Melatonin

1. (a) Where is the biological clock located in mammals?

2. Describe two functions of the biological clock and their adaptive value:

Synchronising circadian and annual rhythms, e.g. basking in tuatara and other reptiles, with changes in the environment.

Time compensation in navigation and sun compass orientation using a continuously consulted clock (e.g. honeybee food collection).

the internal clock is known as entrainment. Endogenous rhythms that are synchronised to specific environmental cues are adaptive, contributing to fitness by ensuring the success of critical activities such as mating, birth, germination, foraging, and periods of torpor and dormancy.

(b) Explain you answer to (a):

The

3. (a) Person A travels 5000 km east in 9 hours. Person B travels 500 km east in 9 hours. Which of these people is more likely to experience jet lag?

(b) Identify a common zeitgeber in animals:

34° °C 40°39°38°37°36°35° LINK 26 WEB 27

Key Idea: External cues synchronise the biological clock with the Biologicalenvironment.clocks stay synchronised with the environment because they are regularly reset by an external environmental cue or zeitgeber. The process of resetting

Most animals travel slowly enough that their biological clock is never far out of sync with the environment and entrainment by the rising of the Sun each day can reset any variation. Travelling west-east (or east-west) in plane can result in the biological clock being severely out-of-sync with environmental cues. This phenomenon is called jet lag

Travelling and biological clocks

2. (a) What is entrainment?

Jet lag occurs because the biological clock is responsible for regulating the natural sleep-wake cycle, which involves being awake and active during the day and sleeping at night when it is dark. Rapid, long distance air travel can lead to disruption of the normal sleep-wake cycle. When travelling across multiple time zones, the biological clock will not be synchronised with the destination time and must adjust to the new schedule.

Zeitgeber (e.g sunlight)

A simple mechanism for biologicalEntrainmentclocks thematchchangesproducemechanisms(internalinternalthatchangesinenvironment).

Biological rhythm (e.g. fluctuations in body temperature)

severity of jet lag is linked to the west–east distance travelled, rather than the length of flight.

environment).clockthecues(environmentalsynchronisebiologicalwiththe Output

(b) Why is entrainment important to an organism?

1. (a) What is a zeitgeber?

Biological clock

Melodi2

Circadian (daily)

Example: NZ long-tailed bats hibernate for 4-5 months during autumn and winter when temperatures are low and insect food is scarce.

Example: Weta are generally active during the night (nocturnal) when they forage in leaf litter or trees. Being active at night makes them less vulnerable to daytime predators.

Circatidal (tidal)

Active Midday MiddayMidnight

Example: Inanga spawn during the months of March and April during the spring tides (new and full moons). Activity peaks 2-3 days after the new or full moon. During the spring tides they are able to lay eggs higher up river banks, which protects the eggs from aquatic predators.

Example: In many domestic livestock species the reproductive cycle is timed so that young are born in spring when the weather is warmer and food is more plentiful.

Term Definition Term Definition

An internally controlled response

An externally controlled response

Period: ~ a year

Endogenous

A rhythm that matches the movement of the tides and has a period of ~12.5 hours.

Rhythm: circadian (daily)

ISBN: 978-1-927309-56-8

Rhythm: circannual (annual)

Circannual (annual) An annual rhythm (one year)

Example: In the New Zealand tunnelling mud crab (Helice crassa) locomotion and feeding occur at low tide. They are more active during the day than at night.

CIRCADIAN: weta

Rhythm: circalunar (lunar) / circannual

CIRCALUNAR: inanga (common galaxias) March May

Mating Birth July December

Period: ~ 29.5 days (a month) / one year

Biological Rhythms

Key Idea: Living organisms show regular cycles of activity that approximate cyclic events in the environment. The activity patterns of organisms often occur with frequencies that approximate the predictable cyclic events in the environment, such as the light-dark cycle and the changing of the seasons. The length of time it takes to complete the entire cycle is termed the rhythm's period, e.g. 24 hours. Rhythms that continue in the absence of external

cues are said to be endogenous (internal). Those that are direct responses to the environment and do not persist when conditions are kept constant are called exogenous. In most cases, the rhythm is the expression of both the internal (endogenous) timing mechanism (the biological clock) and the environmental (exogenous) cue that synchronises it. Biological rhythms are adaptive in that they ensure the appropriate behaviour occurs at the appropriate time.

Period: ~ 12.4 h (coincident with tidal flows)

December

KNOW

Circalunar (lunar)

A rhythm that cycles over an approximately 29.5 day period.

A rhythm that cycles over an approximately 24 hour period.

Exogenous

SpringApriltideSpringtide Springtide Springtide

Period: ~ a year

Period: ~ 24 h

CIRCANNUAL: NZ long tailed bat

CIRCANNUAL: sheep

Active

Rhythm: circannual (annual)

DoC Hibernation December July December LINK 29 LINK 30 WEB 28

CIRCATIDAL: mud crab Active Midday MiddayMidnight High tide High tide

Rhythm: circatidal (tidal)

Photocopying Prohibited

(b) Explain why endogenous and exogenous components are important in maintaining a biological rhythm:

3 For each of the examples below, describe an environmental cue that might be used to induce or maintain the activity:

1. (a) Contrast endogenous and exogenous components of a biological rhythm:

(a) Hedgehog’s hibernation in winter: (b) Blackbird’s foraging and social behaviour during daylight:

2. For each of the following rhythms provide a definition and example and then describe the adaptive value of the rhythm: (a) Circadian rhythm: (b) Circatidal rhythm: (c) Circalunar rhythm: (d) Circannual rhythm:

4. Suggest a way a scientist could discover if an organism's biological rhythm is endogenous or exogenous:

Male calling at dusk, female responding (lasts about 3 hours). NightDay Day

Morning Midnight

are entrained to the environment by external cues, notably the 24 hour light-dark cycle. In animals (below) the circadian rhythm can be further described by the pattern of activity exhibited: diurnal (active during daylight hours), nocturnal (active at night), or crepuscular (active at dawn and dusk).

DATA 38

Sleep in burrow during the day

Major feeding activity 3-4 hours

Morning Midnight Afternoon Dusk Dawn

Brown kiwi Apteryx australis

Afternoon Dusk Dawn

(b) An organism's activity pattern is one aspect of an organism's niche and the result of selection pressures on the species over time. Describe an adaptation of the brown kiwi that is associated with its particular activity pattern:

3. What type of rhythm and activity pattern is displayed by the brown kiwi?

Photocopying Prohibited

2. What type of rhythm and activity pattern is displayed by the kokako?

F&BColbourneRoganSource: Rick Thorp, Dept. of Conservation, Hamilton

4. What features of the kokako's biology and environment might have been important in the evolution of its activity pattern?

Circadian Rhythms in NZ Birds

Sleep in burrow during the day

Brown kiwi inhabit bush and scrub in the North Island and high rainfall forests in the South Island. They are nocturnal feeders, eating worms, insects, and freshwater crayfish. Their eyesight is poor and they are reliant on a keen sense of smell and hearing, exploiting a rich source of food not available to most diurnal birds.

NightDay Day

Feeding with occasional calls to locate mate.

Kokako Callaeas cinerea

Territory call 30 minutes

29 MiddayMidday NightDay Day Dawn MorningDuskAfternoon Usually less active Active Active Active ActiveActive Midnight (c)(b)(a) LINK 28 WEB 29

5. (a) What advantage does the kiwi's activity pattern offer?

Seek burrow just before dawn

Territory call 30 minutes

This endangered species inhabits the native forest canopy. Kokako are poor fliers and move around mainly by running and hopping along branches or gliding between trees. It is a daylight forager, using vision to locate insects, ripe berries, and young leaves.

Sleeps during the night

1. On the diagram at the top of the page, identify the activity patterns (a-c) as diurnal, nocturnal, or crepuscular.

Key Idea: A circadian (daily) rhythm is an endogenous, entrainable rhythm with a period of approximately 24 hours. Circadian rhythms are endogenous rhythms with a period of about 24 hours. They are common in all types of organisms and, although they are endogenous and self-sustaining, they

Quiet: Preening and feedinginspectingareas.

Midnight15

Body temperature

The graph above shows the percentage of 200,000 women who began labour at each hour of the day. If labour were equally likely to begin at any hour, then 1/24 of the women (~4%) would have begun each hour.

Changes in susceptibility to alcohol

The liver’s ability to metabolise alcohol is best between 4 pm and 11 pm (the ‘cocktail hour’). After midnight, the liver’s activity slows down and alcohol starts to accumulate in the

The timing of births and deaths shows daily fluctuation. The graph shows how they vary in frequency compared to a daily mean.

Body temperature shows endogenous fluctuation. Data for the graph above was taken from volunteers lying in bed.

Source: Cycles of Nature - An introduction to Biological Rhythms; Ahlgren, A. and Halberg, F. Rhythmic peak and variability Monthly rhythms in women One menstrual cycle (number of days varies with individual) General Body temperature Heart PupilReactionratetimesize Blood content Red cell count White cell Progesteronecount(hormone) Saliva content PotassiumSodium Daily rhythms 6 am noon12 6 pm midnight12 6 am General Body FiftyAddingMemoryBrainCellBloodtemperaturepressure(diastoic)divisionsinskinwaves(totalEKG)test(speed)numbers(speed)metresprint AsleepAwake Blood content Red cell count White cell count PotassiumSodiumCalciumProlactinTestosteroneInsulinGlucose Months of the year Jan Annual rhythms in Southern Hemisphere General Body SuicideDeathBeardBloodtemperaturepressuregrowthfromdisease Blood content White cell ProlactinTestosteroneCholesterolcount Feb Mar Apr May Oct NovSepAugJulJun Dec levelalcoholBlood Midnight MidnightNoon womenofPercentage labourbeginning Midnight8642 Midnight

Selected human daily rhythms Noon MidnightNoon

37.036.5(temperatureBody ° C) Time

Human Biological Rhythms30 LINK 28 WEB 30

Daily rhythms of birth and death

-150differencePercentage meandailyfrom 37.5Midnight

MidnightNoon of labour onset

DATA 39 © 1988-2016 BIOZONE International ISBN: 978-1-927309-56-8 Photocopying Prohibited Key Idea: Humans exhibit a number of periodic changes in behaviour or physiology that are generated and maintained by a biological clock. In humans, many physiological activities exhibit a circadian, circalunar, or circannual rhythm (below). These rhythms are endogenous, but are entrained by the environment.

blood.BirthsDeaths

6. Describe how beard growth is correlated with the seasons of the year:

7. Different cycles for the same biological variable can occur simultaneously in an organism. The graph at the top of this page shows the body temperature of a woman who stayed underground for four months.

(a) At what time of the day should you sit the exam to provide your best performance?

3. Imagine you are about to sit a theory exam.

(b) Explain why the production of insulin peaks at this time of day:

Rhythms in a long duration cave occupation

38.037.036.0

1. Study the three charts on the previous page and determine when each of the following are at their peak for women:

4. (a) When does insulin peak in the daily cycle?

Photocopying Prohibited

(a) White blood cell count

Daily: Daily:

(d) Explain why this experiment was carried out in a cave environment:

2. Study the graphs for ‘daily rhythms of birth and death’ and ‘body temperature’. Is there any correlation (mutual relationship) between the time of day when most deaths occur and body temperature? Explain your answer:

ISBN: 978-1-927309-56-8

(a) What is represented by the rapid swings in body temperature?

Monthly: Monthly: Annually: Annually:

(b) The same graph also displays a longer undulating rhythm with a period of several weeks. Draw a line of ‘best fit’ through the middle of the ‘rapid swings’ to show this longer rhythm.

5. When, in the daily cycle, is the liver least able to metabolise alcohol?

A woman spent four months isolated underground in a cave so that her biological rhythms could be studied in the absence of the normal day/night environmental cues. The air temperature inside the cave remained constant over this time. Her body temperature was measured 3 times a day for 4 months. 0 5 10 15 (°C)temperatureBody Weeks in isolation underground

(b) Body temperature

(b) Explain your reasoning:

30201024:000

1. Why are actograms produced by double plotting the original raster? 2. (a) What is a free-running period? (b) How would you tell if the free-running period was shorter or longer than 24 hours? LINK 32 WEB 31

The lengths are then laid out one under the other in order, forming a stack called a raster

Double plotted raster

A A

The free-running period in humans is about is about 25 hours. When the free running period is longer than 24 hours the timing of the activity moves to the right on an actogram. When it is less than 24 hours the timing of the activity moves to the left.

24:0012:00 12:00 24:00 Time Days

To maintain continuity between cuts, the raster is copied and pasted to the left but shifted down one line. This is called double plotting and is how most actograms are laid out.

of activity can be seen. By keeping the environmental cues constant (e.g. constant dark) it is possible to see the length of time of the organism's biological clock runs for in the absence of environmental cues. This length of time is called the free-running period. A phase shift occurs when an organism is entrained to a new regime of environmental cues.

Actogram of human activity

Making an actogram

The bars labelled A are the same piece of activity.

Imagine ticker tape rolling out of a machine. Every time an organism is active, a mark or bar is made on the tape. The tape is then cut up into lengths representing 24 hours.

After 10 days, no environmental cues were given to the individual. The light level was set to low but

Key Idea: Actograms are graphical records of an organism's activity and can be used to determine its activity patterns. In a laboratory, the activity of an organism can be recorded continuously. The activity is often recorded as a bar on a line representing 24 hours. By placing the successive blocks of 24 hours under each other, a clearer picture of the pattern

Afterconstant.another 10 days environmental cues were restored but following a new regime. The individual's activity followed the new regime. A shift in the start point of the activity like this is called a phase shift

Tape Raster

Interpreting Actograms

B B The lines labelled B are the same piece of activity.

For the first 10 days the individual was exposed to conditions of 12 hours dark and 12 hours light with no other environmental cues.

Bar showing length of activity

24:00 12:00 24:0024:00 12:00 numberDaynumberDaynumberDay Data: Dr. Bob Lewis, Department of Zoology, University of Auckland. LINK 31

(e) What cue on the shore would the animal use to synchronise its rhythm?

variable to which it is usually entrained. The activity patterns of two species were recorded in the absence of environmental cues to determine the free running period of the rhythm. The results are displayed below as actograms. On each actogram the first day of recording is only shown on the left (day two is outlined and shaded in blue).

(d) Describe a biological advantage to the animal of this rhythm:

Activity Patterns in Animals

The house mouse is a nocturnal animal. The charts above record the activity patterns of two different mice. Their activity was recorded for 7 days, using a running wheel with sensors connected to a computer. During the course of the experiment, the mice were kept in dim light (0.1 lux).

141312109876543211124:00

7654321 Mouse

24:00 12:00 24:0024:00 12:00 7654321 Mouse

Toebiters are small marine isopod crustaceans that scavenge for food in the surf region of sandy beaches in New Zealand. The chart above records the activity pattern over 14 days. During the experiment, the freshly collected toebiter was kept in total darkness at a constant temperature of 20°C. Cirolana sp.

(b) What type of rhythm is shown?

2. What type of rhythm is shown?

Photocopying Prohibited

4. (a) Determine the period for the toebiter's activity over the 14 days of the trial:

Toebiter

5. What evidence do you have that the rhythms shown above are endogenous?

House mouse Mus musculus 12:00 24:0024:00 12:00 B A

1. Determine the periods for each mouse's activity over the 7 days: (a) Mouse A: (b) Mouse B:

3. Briefly describe two differences in the activity patterns of these two mice: (b)(a)

Key Idea: A free-running endogenous rhythm usually has a slightly different period from the cyclic environmental variable that entrains it. The rhythm can be recorded as an actogram. In the absence of an external zietgeber (such as light) an endogenous rhythm will adopt a free-running period, which is usually slightly different from the cyclic environmental

6 What type of rhythm is displayed in the first 10 days?

Cockroaches are nocturnal insects. The experiments below investigated the periodicity of their behaviour under controlled conditions. The first experiment determined the free-running period. The results of the second experiment show the entrainment of the rhythm. Note the actograms below are not double plotted.

Days 121098765432111 012345678910 OriginalNew HoursLight Lightregimeregime Light LightDarkness 10987654321 24 hours Days 0 24 20191817161514131211 Darkness24hours0 24 Light regime

Recall that the process by which the endogenous rhythm is synchronised to an environmental cue (or zeitgeber), such as a 12 hour light /12 hour dark cycle, is termed entrainment. The chart on the right shows the activity record of a cockroach. It is being entrained to a new light cycle, which occurs nine hours earlier than the one it had been experiencing previously.

Cockroach activity

Entrainment

8. Describe the activity pattern displayed by the cockroach:

10. Describe the effect of entrainment on the free-running period, and explain its adaptive value in a natural environment:

Entrainment usually has the following features:

The charts on the right record the activity rhythm of a cockroach kept for 20 days in a running wheel actogram. There are activity records shown for each of the 20 days, with each day's record presented in succession down the page. The periods of activity are shown as grey rectangular blocks and periods of inactivity shown as no rectangle.

The onset of constant darkness on day 11 exposed the free-running period and produced a phase shift.

Light regime

This is the term used to describe the cycles of light and darkness. It is indicated by bars of 'light' and 'darkness' at the bottom of each table:

Free-running period

Days 1-10: Days 11-20:

• As the activity gets nearer the new lights-out signal, the daily phase shift is reduced.

• A phase shift for the start of the activity is gradual, without jumps.

7. In what part of the light/darkness cycle was the cockroach most active?

9. Determine the free-running period (in hours) displayed between days 11-20:

Key Idea: Plant hormones play crucial roles in the timing of activities including fruit ripening and breaking dormancy. Many of the responses of plants to cues in the environment, such as low temperatures and daylength are mediated by hormones. Low temperature stimulation of flowering (vernalisation) and seed germination (stratification) are common in many species. They are examples of responses mediated by plant hormones, and enable the plant to track

Abscisic acid (ABA) promotes dormancy, preventing development of the leaf and flower bud under unfavourable conditions

The seeds of many cold-climate plants will not germinate until they have been exposed to a period of wet, cold (5°C) conditions. This is called cold stratification

Deciduous plants shed their leaves every autumn in a process called abscission. A decline in auxin (IAA) and an increase in ethylene work together to bring about leaf drop. Losing leaves conserves resources at a time when there is not enough light for photosynthesis and the cold weather may damage the delicate leaf structures.

and respond to seasonal changes. Plant hormones are chemicals that act as signal molecules to regulate plant growth and responses. Alone or together, plant hormones target specific parts of a plant and produce a specific effect. Many have roles in coordinating timing responses in plants including promoting and breaking bud dormancy, seed germination, and fruit ripening. In addition these rhythms are linked to temperature.

doirepycnamroD

Bud burst and flowering follow exposure to a cold period in many plants, including bulbs and many perennials. This process is called vernalisation and it ensures that reproduction occurs in spring and summer, not autumn. Gibberellins are important in breaking bud dormancy.

Fruitdevelopment

December August MayNovemberJuly March October June February September April January Hormones, plant growth, and fruiting

Seed

Ethylene is a gaseous plant hormone with an important role in the ripening process of many fruits. Auxin and ethylene are believed to work together to promote fruit fall

Auxins and gibberellins are important in promoting the growth and development of shoots.

ABA accumulates in seeds during fruit production and is important in seed dormancy. A high level of ABA in the seed embryo promotes dormancy.

germination and hormonesLeafandflowerdevelopment

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Dormancy is a condition of arrested growth. The plant, or its seeds or buds, do not resume growth until increasing daylength and temperatures provide favourable growing conditions in spring.

Gibberellins are required for seed germination. They stimulate cell division and cell elongation, allowing the root to penetrate the seed coat.

2. How does vernalisation ensure a plant will not flower in autumn?

Many flowers, including tulips, show sleep movements. In most species, these are triggered by daylength, but in tulips the environmental cue is temperature. This series of photographs shows the sleep movements of a single tulip flower over one 12 hour period during spring. Sleep movements may prevent flower damage, stop the entry of non-pollinating insects, or stop the pollen becoming wet with dew.

(b) What cues are likely to be involved in breaking dormancy?

1. (a) Describe the adaptive value of dormancy in plants:

5. Describe is the advantage of cold stratification in plant seeds:

3. Describe the adaptive value of leaf abscission:

Daily rhythm in tulips

4. Why is it likely that the same hormones are responsible for both leaf fall (abscission) and fruit fall in plants?

(b) How might these movements be adaptive?

6. (a) Describe the sleep movements of tulips in response to temperature:

RAphotos:All 5.00 pm11.00 am9.30 am 7.00 pm7.00 am

Pfr is the physiologically active form of phytochrome. It promotes flowering in long-day plants and inhibits flowering in short-day plants.

Phytochrome is a blue-green pigment that acts as a photoreceptor for detection of night and day in plants and is universal in vascular plants. It has two forms: Pr (inactive) and Pfr (active). Pr is readily converted to Pfr under natural light. Pfr converts back to Pr in the dark but more slowly. Pfr predominates in daylight. The plant measures daylength (or rather night length) by the amount of phytochrome in each form.

yoSlwlindarkness

Phytochrome

In daylight or red light (660 nm), Pr converts rapidly, but reversibly, to Pfr.

Rapidconversion

2. (a) Discuss the role of phytochrome in a plant's ability to measure daylength:

of a pigment called phytochrome. Phytochrome acts as a signal for some biological clocks in plants and exists in two forms, Pr and Pfr. It is important in initiating flowering in longday and short-day plants, but is also involved in other light initiated responses, such as germination and shoot growth.

Key Idea: Photoperiodism is the response of a plant to the relative lengths of light and dark. It is controlled by the pigment phytochrome, which occurs in two forms Pr and Pfr Flowering is a photoperiodic activity that is dependent on the species' response to light. It is controlled through the action

Photoperiodism in Plants

Pfr Pr

1. (a) Identify the two forms of phytochrome and the wavelengths of light they absorb:

(b) Identify the biologically active form of phytochrome and how it behaves in long day plants and short day plants with respect to flowering:

Phytochrome interacts with genes collectively called "clock genes" that maintain the plant's biological clock.

There is still uncertainty over what the flowering hormone (commonly called florigen) is. Recent studies suggested it may be the protein product of the gene FLOWERING LOCUS T (FT) (in long day plants at least) which appears to influence gene expression that includes the gene LEAFY (LFY) in the apical meristem and causes flowering.

Physiologically active

The hormone is transported to the apical meristem where it causes a change in gene expression that leads to flowering.

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(b) Explain how this helps to coordinate flower production in a plant species?

Sunlight “ClockFloweringgenes”hormone

In the dark or in far red light (730 nm) Pfr reverts slowly, but spontaneously, back to the inactive form of phytochrome Pr.

Photocopying Prohibited

For the example of the Chrysanthemum, a shortday plant, flowering is can be controlled under the following conditions. The temperature is kept between 16 - 25 oC. The light-dark regime is controlled at 13 hours of light and 11 hours of dark for 4-5 weeks from planting to ensure vegetative growth. Then the regime changes to 10 hours light and 14 hours darkness to induce flowering.

An experiment was carried out to determine the environmental cue that triggers flowering in 'longday' and 'short-day' plants. The diagram below shows 3 different light regimes to which a variety of long-day and short-day plants were exposed.

Short

3. (a) What is the environmental cue that synchronises flowering in plants?

ShorShort-day

When subjected to the light regimes on the left, the 'short-day' plants below flowered as indicated:

5. Alternating cycles of short light and short dark inhibit flowering in SDP.

Long day vs short day plants

E xamples : potatoes, asters, dahlias, cosmos, chrysanthemums, pointsettias

When subjected to the light regimes on the right, the 'long-day' plants below flowered as indicated:

2. Interruption of the long dark period inhibits flowering in SDP but promotes flowering in LDP.

Chrysanthemums

6. Plants that do not use daylength to initiate flowering are called dayneutral (e.g. cucumber, tomato).

Long-dLong-day Short-day Long

024hours

5. What evidence is there for the idea that short-day plants are best described as "long-night plants":

E xamples : lettuce, clover, delphinium , gladiolus, beets, corn, coreopsis

No NoFloweringfloweringflowering

(a) Short-day plants:

Long-day plants

1. Long-day plants (LDP) flower when the photoperiod is greater than a critical day length. Short-day plants (SDP) flower when the photoperiod is less than a critical day length.

(b) What is a biological advantage of this synchronisation to the plants?

Short-day plants

Long night interrupted by a short period exposed to light night night night

NoFloweringfloweringFlowering

Long

Photoperiodism in plants

Manipulating flowering in plants

Controlling the light-dark régime has allowed flower growers and horticulturists to produce flowers out of season or to coincide flowering with specific dates.

Plants kept in greenhouses can be subjected to artificial lighting or covered to control the amount of light they receive. To be totally effective at controlling flowering, temperature must also be controlled, as this is also an important flowering cue.

(b) Long-day plants:

4. Interruption of the light period inhibits flowering in LDP but not in SDP.

4. Study the three light regimes above and the responses of short-day and long-day flowering plants to that light. From this observation, describe the most important factor controlling the onset of flowering in:

3. Dark must be continuous in SDP but not in LDP.

Photoperiodism in plants

ISBN: 978-1-927309-56-8

HINT: Include definitions and reference to the role of phytochrome.

REVISE 48

Biological rhythms in animals

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HINT: Include definitions that clarify the length and type of rhythm involved.

Biological rhythms in plants

What You Know So Far: Orientation in Time35

HINT: Include reference to phytohormones and the timing of key events in plant life cycles.

Investigating circadian rhythms

HINT: Explain how activity patterns are recorded and include reference to freerunning period and entrainment.

Fiddler crabs live on tidal mudflats. They feed on detritus in the mud at low tide, and return to their burrow at high tide to rest. The diagram below shows the actogram for a fiddler crab's activity in a laboratory. The crab was kept in constant light.

(b) Identify the origin of the biological rhythms:

Style Question: Biological Clocks in Animals

1. (a) Identify the two biological rhythms shown by the crab:

3. Discuss the role of biological rhythms in animals, using the fiddler crab as an example. Include the origins of biological rhythms, the importance of zeitgebers, and the importance of accurate timing. You may use extra paper if required:

0 Days121098765431211

Simplified actogram for fiddler crab 6 12 18 24

2. Explain the pattern seen in the actogram. Predict the continued activity of the crab in the lab in relation to the high tide at the beach of collection:

High tide at beach of collection Times crab was activeTime of day (hours)

(b) Explain how phytochrome controls flowering in carnations:

NCEA Style Question: Biological Clocks in Plants37

2. Tulips have large flowers with petals that open during the day and close at night. Discuss how this regular movement of the petals enhances the plant’s reproductive success. You may use more paper if required.

(a) Describe this pattern of flowering:

1. Carnations require at least two or three weeks with days longer than 14 hours to initiate flowering. Flowering is controlled by the pigment phytochrome in response to the photoperiod.

3. Some plants respond to seasonal changes by alternating periods of growth and dormancy. Describe the environmental cues that are important in these life cycle responses and discuss their adaptive value:

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1. Match the following words with their definitions:

G The period of an endogenous rhythm when given no external environmental cue by which to synchronise the rhythm.

L A stimulus originating within the organism itself, e.g. hormonal changes, is this.

(a) A whelk kept in the laboratory becomes active every 13 hours:

biological clock biological rhythm circadian zeitgebershort-dayphytochromephotoperiodismlong-dayfreeexogenousentrainmentendogenousrhythmrunningperiodplantplant

2. Name the type of rhythm in the following examples:

KEY TERMS AND IDEAS: Orientation in Time

I An endogenous timing system an organism uses to synchronise its activities with the environment.

3. Identify the plants A, B, and C as short day, long day, or day neutral plants based on their flowering under the light schemes shown below (flowering F, no flowering NF):

(b) How can you tell? DAY 12 12 242424Time (hrs)

F An environmental stimulus that is external to the organism (e.g. day length) is referred to as this.

E A plant that flowers when daylength is more than a critical value (~12 hours).

A The synchronisation of an endogenous rhythm with an external cycle such as light and dark.

(b) The body temperature of a human in an isolated room rises and falls over 24 hours:

Active

J An endogenous rhythm of rest and activity that approximates 24 hours and is entrained by the light-dark cycle.

(a) Plant A:

B A plant that flowers when daylength is less than a critical value (~12 hours).

D A pigment in plants responsible for the photoperiodism effect. Regulates the timing of flowering with different effects in long day and short day plants.

A B C F NF F NF F F NF F F

K Physiological changes or changes in activity in living organisms occurring in a cyclic manner. Most often associated with predictable daily, monthly, or annual environmental changes.

(b) Plant B:

4. The activity of a species of fly was recorded under constant conditions in a lab and an actogram made:

C The physiological reaction of plants and animals to the presence and absence of light.

Night

H An exogenous cue that synchronises an organism's endogenous rhythms to the rhythms of the environment, e.g. the Sun or the light-dark cycle.

(a) Was the free-running period of the fly longer or shorter than 24 hours?

The adaptations of predators and prey are the result of coevolution: predators capture.adaptationspreyadaptationshavetocaptureandpreyhavetoavoid

Herbivore eats parts of a plant and usually does not kill it. Plants often have defences to limit the impact of herbivory.

Both species benefit from the association.

Examples: Lion preying on wildebeest or praying mantis (below) consuming insect prey.

Type of interaction between species

Species Interactions

No organism exists in isolation. Each interacts with other organisms of its own and other species. Species interactions (those between different species) involve benefit to at least one party. If one party benefits at the expense of another, the

diagram above) that matches each

The parasite lives in or on the host, taking (usually all) its nutrition from it. The host is harmed but usually not killed.

over-browsing?SteveGarviecc2.0www.Lucnix.beViatourLuc WEB 39

(b) How might this response prevent

ISBN: 978-1-927309-56-8

Individuals of the same or different species compete for the same resources, with both parties resourcesespeciallysuffering,whenarelimited.

Mutualism Exploitation CompetitionPredation Herbivory Parasitism

Examples: Pork tapeworm (below) in a pig's gut. Some plants (e.g. mistletoes) are nutrientsrobphotosynthesise(hemi-parasites).semi-parasiticTheybutthehostplantofandwater.

Flowering plants and their insect pollinators have a relationship.mututalisticFlowers are pollinated and the insect gains food (below).

A B Benefits Benefits A B Benefits Harmed A B Benefits Harmed A B Benefits Harmed A B HarmedHarmed

of our interaction with another species (B in

2. Plants are not defenceless They have evolved physical and chemical defences to deter herbivores. In some cases (as in stimulates in the

A in

(c)

Examples: Tick bird on zebra removes parasites and alerts zebra to danger, while tick bird gains access to food.

plant.

Key Idea: All species interact with their own and other species. These interactions carry costs and/or benefits to the parties involved.

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(a) What is the acacia's response to giraffe browsing?

Predator kills the prey outright and eats it.

growth

KNOW

exercise, assume that

purposes of

represents

Example: Giraffes browsing acacia trees. Browsing stimulates the acacia to produce toxic alkaloids, which cause the giraffe to move on to another plant. Acacia thorns also deter many browsers.

relationship is an exploitation. If one species benefits and one is unaffected, the relationship is said to be commensal Some species interactions involve a close association or symbiosis (living together) between the parties involved. Symbioses include parasitism and mutualism. Many species interactions involve coevolution, in which there is a reciprocal evolution of adaptations in both parties.

1. For the this species the diagram humans. Briefly describe an example the of

Competition:

Examples: Monarch caterpillars compete for access to milkweed. Those hatched later in the season may starve. Plants growing close to each other compete for light and soil nutrients.

against herbivores.

the following interaction types: (a) Mutualism: (b) Exploitation:

grasses) grazing

(b) Describe how each species is affected (benefits/harmed/no effect):

rose)Short-tailed bat

(a) Identify this type of interaction:

(d) Describe how each species is affected (benefits/harmed/no effect):

6. In many New Zealand beech forests, kaka feed on honeydew, a liquid excreted by a scale insect feeding on the beech tree (left). These scale infestations are common although there is no evidence that they harm the tree. Introduced wasps also feed on the honeydew and often attack kaka trying to do the same.

(a) Identify this type of interaction:

Examples of interactions are illustrated below. For each example, identify the type of interaction, and explain how each species in the relationship is affected.

(b) Describe how each species is affected (benefits/harmed/no effect):

(c) Dactylanthus taylorii is pollinated by the short-tailed bat, which feeds on the musky smelling nectar produced by the flowers during summer. Identify this type of interaction:

5. Dactylanthus taylorii is an endangered endemic New Zealand plant. It does not photosynthesise, but grows attached to the root of host tree species (e.g. seven finger or patē) from which it derives all its nutrients.

(a) Identify this type of interaction:

3. Clownfish spend much of the time taking refuge among the tentacles of this large sea anemone. They help protect the anemone from predators and gain significant protection from predators themselves.

(b) Identify the interaction between the wasp and the kaka. Describe how each species is affected (benefits/harmed/no effect):

between different species

Anal tubules of beech scale insects with honeydew dropletsConservationofDeptBarkle,J.ConservationofDeptVeitch,C.R.LtdHoneyAirborneBray,Peter

(a) Identify the interaction between the scale insect and the beech tree. Describe how each species is affected (benefits/harmed/no effect):

Dactylanthus taylorii (wood

(b) Describe how each species is affected (benefits/harmed/no effect):

4. Oxpecker or tick birds feed on the skin parasites of large herbivores, such as Cape buffalo, zebra and rhinoceros. These birds will act as an early warning system by calling when predators approach.

Acacia ants nest within the thorns of the bullhorn acacia. In exchange for shelter, the ants protect acacias from attack by herbivores. There is a resource component though because the ants feed on the lipid rich bodies at the tips of the acacia leaflets.

Many large grazing mammals rely on oxpeckers to remove parasite infestations. The grazers provide food to the birds and the birds provide an anti-parasite service.

Key Idea: Mutualistic relationships benefit both species involved. Often the benefit (to at least one party) is food. Mutualism is a symbiotic relationship between two different species in which both interacting species benefit from the association. It can be contrasted with exploitation or parasitism in which one animal benefits while the other does

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Termites, which feed on wood, rely on a community of microbes in their gut to break down the cellulose in wood and produce the fatty acids the termites use for energy. The obligatory relationship (opposite) provides food for both microbes and termites.

Resource-resource relationships: One resource is traded for another (usually food or a nutrient).

Types of mutualistic relationships

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Some species of ants "farm" aphids by protecting the aphids from predation by ladybirds. In return the ants harvest the honeydew produced by the aphids.

KNOW

Clownfish protect their home sea anemone by chasing away predators, e.g. butterfly fish. In return, the anemone protects the clownfish from its predators. However, the anemone's symbiotic algae also benefit from the nitrogen excreted by the clownfish.

not. Some mutualistic relationships are obligate, meaning that one (or both) species can not survive without its mutualistic partner. Other mutualistic relationships may not have the same level of dependency, and the relationship is not necessary for the survival of either species. These associations are termed facultative mutualism.

Service-service relationships: Both organisms provide a service to each other. True service-service mutualisms are very rare and there is usually some sort of resource component present.

Mutualism Involving Animals

Service-resource relationships: A service is performed in exchange for a resource, e.g. food for protection.

Many reef building corals rely on a mutualism with algae in their tissues. The corals obtain some of their energy from the algae. The algae obtain a habitat and utilise the coral's nitrogenous waste and carbon dioxide.

(b) Explain your answer:

Pollen grains

1. (a) Define the term mutualism: (b) Distinguish between facultative and obligate mutualism:

obligate or facultative

White-tailed deer

NOAA

Honeybee pollinating a purple crocus

can

2. The image shown right shows the Riftia tube worm, which lives near hydrothermal vents deep in the ocean. The worms have no digestive tract and rely on symbiotic bacteria for nutrition. In return, the bacteria are provided with the safe stable internal environment of the worm in which to live.

Mutualistic relationships be

(a) Is the relationship between the worm and the bacteria an obligate or facultative relationship?

3. Describe three broad classes of benefits that seem to be most common in mutualism: (c)(b)(a)

In a facultative mutualism, both species benefit from interacting with each other but can survive without the interaction. In many cases, a species may interact mutualistically with many similar species. For example, bees pollinate many different types of flower. The flower can use any type of bee as a pollinator and the bee can visit any type of flower to gather nectar.

4. Service-service mutualisms, such as the clownfish-anemone relationship, appear to be very rare. What might suggest that there is a resource component to these relationships?

In an obligate mutualism, neither species can survive without the other. There is a mutualistic relationship between many herbivores and the microbes in their gut, which enables cellulose to be digested. In ruminants, the rumen microflora break down the cellulose in forage and the ruminant obtains energy from the volatile fatty acids released by the microbial activity. The microbes benefit by having a stable growth environment and a food supply.

fixation in legumes occurs within root nodules, which are extensions of the root tissue formed in response to bacterial entry. The nodules provide the low oxygen environment necessary for nitrogen fixation. The presence of nodules allows plants to grow successfully even when soil nitrate is low.

Because plants are unable to move they must have effective strategies for reproduction and acquiring nutrients. Most

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KNOW

Mycorrhizae are formed by the mutualistic association between a fungus and the roots of a vascular plant. The fungus colonises the plant roots, either intracellularly or extracellularly, forming the mutually beneficial mycorrhizal association.

Around 85% of vascular plant species have mycorrhizal associations and they are vitally important to plant health and forest ecology. The fungal mycelium provides a vast surface area, improving the plant's capacity to absorb minerals and water. In addition, the fungus can access phosphate ions, which are largely unavailable to the plant roots, and transfers them to the plant. In return, the plant provides the fungus with a supply of carbohydrate (produced by photosynthesis). Many conspicuous fungi in the forest, e.g. fly agaric (A), are ecotomycorrhizal. The mycorrhizal roots (B) are short and stubby with a film of fungal threads enveloping them.

WBS 3.0ccKempJeremy LINK 39 LINK 40 WEB 41

Key Idea: Plants form mutualistic relationships with animals, fungi, bacteria, and other plants.

Mycorrhizal associations

1. Root nodules are a mutualistic relationship between a bacterium and a plant. Describe the benefits of the relationship to: (a) The plant: (b) The bacterium: 2. When might legumes have a clear competitive advantage over plants that cannot fix nitrogen? Explain your answer: Mutualism Involving Plants41 A B 3.0ccThergothonphotos:Both

plants form mutualistic relationships with fungi that help to provide nutrients to the roots in exchange for carbohydrate from the plant. Plants use many different types of animals to facilitate pollination.

Nitrogen fixation in root nodules

Nitrogen fixing bacteria reduce nitrogen from the atmosphere to ammonium ions, combining them with organic acids to produce amino acids. The amino acids provide a nitrogen supply to the plant and the bacteria gain a supply of carbohydrate and a suitable environment in which to grow.Nitrogen

Root nodule

Nitrogen fixation is a crucial part of the nitrogen cycle. Nitrogen is an abundant element, but biologically available nitrogen compounds are relatively scarce, so plants that are able to form a mutualistic relationship with bacteria to fix nitrogen have a nutritional advantage.

Plants in the legume family (e.g. peas, beans, and clover) and nitrogen fixing bacteria (e.g. Rhizobium) form a mutualistic relationship with considerable nutritional benefits to both parties.

f Mistletoes are hemiparasitic (partly parasitic) flowering plants. They are photosynthetic but use specialised roots to gain water and nutrients from their host plant. There are eight species of mistletoe native to New Zealand. Unlike mistletoes in other countries, New Zealand mistletoes do not harm their hosts.

4. (a) Horticulturists frequently add a mycorrhizal inoculum when transplanting plants. Suggest why they would do this:

f Tui and bellbirds feed on a variety of plant species but are primarily responsible for beech mistletoe pollination and are also the main dispersers of the pea-sized fruits. Seed dispersal is critical to mistletoes because the seed must land on a suitable host tree.

(b) Why would they not add phosphorus fertiliser when attempting to establish the mycorrhizae?

Tui on beech mistletoe

3. Describe the mutualism between vascular plants and mycorrhizal fungi, including benefits to plant and fungus:

CanterburyofUniversityLadley,JennyPHOTOS:

f The two species of New Zealand beech mistletoes (Peraxilla) are pollinated by tui and bellbirds, which are nectar feeders and have adaptations to penetrate the mistletoe flower and access the nectar. Even when the flower is ready for pollination (ripe), the petals are closed. When tui and bellbirds give the ripe flower a squeeze with their beak, the petals spring open to reveal the inside of the flower. The birds can then feed, collecting pollen on their heads, which they transfer to different plants as they move between flowers. Native solitary bees are also known to open the flowers by chewing the tips until they spring open.

5. (a) Explain how the mutualism between NZ beech mistletoes and its bird pollinators benefits both parties:

Mistletoe pollination

(b) How is the dependency of the relationship different for the mistletoe and the bird pollinator?

Bellbird on beech mistletoe

1. (a) On the graph above, mark (using different coloured pens) where the peak numbers of woolly aphids and giant ladybirds occurs:

Aphids feed off the bamboo sap, and the ladybirds are predators of the aphids (below).

The graph below shows the relationship between the giant lady bird beetle and the woolly aphid when grown in controlled laboratory conditions.

Giant ladybird beetles (Anisolemnia dilatata) feed exclusively on the woolly aphids of bamboo plants. There is some interest in using them as biological control agents to reduce woolly aphid numbers, and limit the damage woolly aphids do to bamboo plants.

not usually the case. Prey species are more likely to be regulated by other factors such as the availability of food. However, predator population cycles are often regulated by the availability of prey, especially when there is little opportunity for switching to alternative prey species.

Sampling week

aphidsofNumber

2. (a) Is the trend between the giant ladybirds woolly aphids positive or negative (circle one).

International

KNOW

(b) Do the peak numbers for both species occur at the same time?

Bamboo plants are home to many insect species, including ladybirds and aphids.

In some areas of Northeast India, a number of woolly aphid species colonise and feed off bamboo plants. The aphids can damage the bamboo so much that it is no longer able to be used by the local people for construction and the production of textiles.

A case study in predator-prey numbers

(2013)Agarwala&MajumderSource: 55-61(1):8ZoologyofJournalWorld 1030405060708090200 642081012 ladybirdsgiantofNumber

Photocopying Prohibited 58 Interpreting Predator-Prey

ISBN: 978-1-927309-56-8 Relationships

Key Idea: Predator and prey populations frequently show regular population cycles. The predator cycle is usually based on the intrinsic population cycle of the prey species. It was once thought that predators regulated the population numbers of their prey. However, we now know that this is

(b) Explain your answer:

LINK 39 WEB 42

Aphid Ladybirdpopulationpopulation

Undergroundprobing

Key Idea: Interspecific competition is often reduced by different species exploiting slightly different resources. Competition is most intense between members of the same species because their habitat and resource requirements are identical. Interspecific competition (competition between

T Miromiro

South Island beech forests are home to a number of insectivorous birds. The six species above inhabit the same region of bush and all are partially or completely insectivorous. This appears to be a contradiction of Gause’s competitive exclusion principle, which states: “When different species compete for the same resources in the habitat, one eventually prevails and displaces the other”. Niche differentiation enables the species to avoid direct competition by exploiting slightly different food resources or the same foods in a different way or at different times. All six species have slightly different hunting strategies. The robin is a ground feeder, searching through the leaf litter for adult insects and larvae. The grey warbler picks insects from the tree bark

associationsHawking,flushing,feeding

Bark gleaning

or ngiru-ngiru (tomtit) Rf Tititi pounamu (rifleman)

different species) is commonly less intense because species with similar ecological requirements have evolved slight differences in the resources they exploit or in the way they exploit them. The evolution of these differences is called niche differentiation.

drawn to scale)

FlyingandfeedingHawkinggleaninginsectsFoliageandbarkgleaning

F W T Rf

(gleaning). Fantails use several strategies to capture insects on the wing. In open vegetation, they use hawking, perching in open vegetation to spot insect swarms and flying out to capture them. In denser bush, they fly around to flush insects out for easy capture. They also use feeding associations, following other birds and even humans to capture insects disturbed by another's activities. The tomtit exploits upper and lower forest strata both gleaning and hawking; whichever is the most rewarding at the time of day. The rifleman feeds methodically, spiralling up a tree trunk from the base and picking insects from the surface or from cracks in the bark. The brown kiwi probes beneath the litter with its long beak and feeds at night.

2. Describe the feeding niche for each of the birds listed above (i.e. where, when, and how do they feed):

Ground

K Brown kiwi

(f) Brown kiwi:

Ro (robin)Toutouwai

(d) Tom tit:

K Ro Flying insects

(b) Warbler:

(a) Fantail:

(fPiwakawakaantail) W (greRiroriroywarbler)

(e) Rifleman:

(Not

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1. Why is interspecific competition usually less intense than intraspecific competition?

The Effects of Interspecific Competition

6. What evidence is there that competition restricts bumblebee species to certain flower types? species

Proboscis Corolla

Studies on bumblebee foraging have shown that when bumblebees forage in the presence of other bumblebee species they tend to spend the majority of their time on particular flower types. In many cases, the length of the corolla (the length of the flower petals) of flowers visited correlates with the length of the bumblebee's proboscis (mouthparts).

Bumblebee species in the mountains of Colorado (graph right) compete for nectar from flowers. Species with a long proboscis take nectar from flowers with long petals. Species with a short proboscis take nectar from flowers with short petals. This reduces competition for food between the bumblebee species.

Adaptations reduce competition in foraging bumblebees

Heuchera

167

Bombus kirbyellus Bombus appositusproboscisShortproboscisLong 1280 1280

Bombus frigidus Bombus bifarius

VisitsF. to

4. Explain why the coexistence of the six NZ bird species does not violate Gause’s competitive exclusion principle:

hourpervisitsofNumber

The bumblebees Bombus appositus and Bombus flavifrons normally show a preference for particular flower species (call these A and F respectively for reference). However, in the absence of competition, they will forage on either flower species. This was shown in an experiment in which visits of Bombus appositus to its usual forage flower A were restricted. Bombus flavifrons, which usually forages on flower F, responded by increasing its visits to flower A and decreasing its visits to flower flower A

3. Describe two ways in which species can avoid directly competing for the same resources in their habitat:

(b)(a)

0 4 8 12 Bumblebee

5. (a) How do the Bombus species in Colorado reduce competition for flower resources? (b) Are the differences between the Colorado species mainly structural, physiological, or behavioural? Explain:

Flower corolla length (mm) 1280

Bombus flavifronsBombus appositus Experiment 49 Experiment 84

Control

Wildebeest

1. Complete the tables of relationships below for the examples illustrated, filling in the type of relationship, the effect (+, –, 0) and the species involved. The first one has been done for you. In the beech example, use the same answer format:

Key Idea: Species interact in ways that are broadly similar regardless of the ecosystem in which they are found.

Interactions between zebras and other species Interaction Zebra Species B

Michael (inski) CC 3.0 Rudolph89 CC3.0 J. Ladley UoC

On the savannah, the zebra's main predators are lions (right) and hyaenas. Herbivory is a similar type of exploitation, except that the plant is usually not killed by the herbivore and may even benefit from regular cropping.

Photo:

The association between the roots of Nothofagus and the fungus Amanita nothofagi (right) is a mutualism These associations, or mycorrhizae, help the trees to absorb water and nutrients from the soil. In return, the fungi are provided with sugars from the tree.

Competition

Brushtail possums (left) are a major pest species in New Zealand, causing significant damage to native trees by eating their leaves, flowers, and fruit. When Nothofagus fruits heavily, more than 40% of a possum's diet can come from its flowers, fruit, and seeds.

with other grazing mammals, such as wildebeest, for grazing space, forage, and water. This may be critical when resources are scarce, e.g. during a drought.

Species interactions in a Nothofagus (southern beech) forest

Interactions between Nothofagus and other species Interaction Nothofagus Species B

The southern beech (Nothofagus), pictured left, has a competitive advantage over other New Zealand tree species, such as tawa, in areas of suboptimal soil or harsh climatic conditions. Many Nothofagus species are able to tolerate the low light of the subcanopy, and can grow rapidly.

Species interactions on the African savannah

Identifying Species Interactions in Ecosystems

Ectoparasites, such as ticks (left) mites, and fleas, live attached to the skin or hair of the host, where they suck body fluids, cause irritation, and may act as vectors for disease-causingmicroorganisms.Zebrascompete

Red mistletoe (left) is a hemiparasite of beech. It can photosynthesise, but it takes water and nutrients from the beech root system. The mistletoe is an important food source for bellbirds and tui who compete for nectar but also pollinate the mistletoe flowers.

HINT: How does competition affect the competing species?

HINT: Predation, herbivory, and parasitism. How are the parties involved affected?

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Competition between species

What You Know So Far: Interspecific Relationships

Mutualism

REVISE 62

HINT: How do organisms benefit from mutualistic relationships?

Exploitation

Rudolph89

1. Rhabdothamnus solandri (taurepo) is the sole member of the plant family Gesneriaceae and is native to New Zealand. The shrub grows to about two metres tall and produces red and yellow trumpet shaped flowers. About 8% New Zealand's plants are bird pollinated. R. solandri's flowers are pollinated by tuis, bellbirds, and stitchbirds, with bellbirds and stitchbirds being the key pollinators.

• Explain why the decline in R. solandri populations is linked to declines in bird populations.

Rhabdothamnus solandri

Style Question: Interspecific Relationships

In your answer you should:

Discuss the relationship between R. solandri and its pollinators (bellbirds and stitchbirds) and why populations of R. solandri are in decline.

Research has found that on the North Island mainland, pollination of flowers (and hence seed production) has declined as bellbird and stitchbird populations have declined. On offshore island sanctuaries where bird pollinators are still present in large numbers, pollination of the flowers is still high.

• Describe the interspecific relationship between the pollinators and R. solandri and the advantage of this relationship to the species involved.

• Justify why efforts to reestablish locally extinct bird populations in the North Island could have larger ecological effects than just the return of the birds to the environment.

A A mutually beneficial interaction between individuals of different species.

2. Cleaner shrimps are various species of shrimp that have the habit of picking parasites from the mouth and gills of fish that attend "cleaning stations" on tropical reefs.

TEST 64

D Competition occurring between members of different species.

(b) Explain how each species benefits or is disadvantaged in the interaction:

ISBN: 978-1-927309-56-8

KEY TERMS AND IDEAS: Interspecific Relationships

E Any interaction between individuals (of different species) in which one individual benefits and the other is affected detrimentally, e.g. parasitism, predation, herbivory.

(a) Name this type of interaction:

(b) Explain how each species benefits or is disadvantaged in this interaction:

interspecificexploitation competition

(a) Identify this type of species interaction:

4. The graph right shows the population of a predator species (A) and a prey species (B) in an area of forest over 3 years.

B The relationship where an individual of one species kills and eats the individual of another species.

(b) Describe the likely causes of this pattern of population fluctuation:

AspeciesofNumber 0

(a) Describe the general pattern of the population numbers shown:

BspeciesofNumber Years 1

3. When a large mammal dies on the African savanna, the carcass is quickly found by scavengers. Many different species may try to get a share of the meat and fighting often occurs:

C A type of symbiosis between organisms of different species where one organism benefits at the expense of the host.

3.0CCInagloryBrocken

following words with their definitions:

2 3

1.predationparasitismmutualismMatchthe

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The two male baboons on the right are engaged in a dominance display. Both animals are acting as senders and receivers of a message.

2. (a) Explain the role of releasers in behaviours involving fixed action patterns:

GratwickeBrian

FAPmechanismreleasingInnate

(b) Name a releaser for a fixed action pattern in gulls and describe the behaviour elicited:

The message conveyed from one individual to another: Aggression, submission, courting, social bonding

Rules that enable the receiver to decipher the signal

The correct transmission of some messages is so critical that the method of transmission has become genetically fixed and the behaviour cannot be altered by learning or external stimuli. This kind of behaviour is called a fixed-action pattern (FAP). FAPs are spontaneous, stereotyped (always the same), and indivisible. Once begun, a FAP runs to completion and is independent of learning. Many FAPs have been identified in animals. The one illustrated below relates to feeding the southern black-backed gull (Larus dominicanus). Similar behaviour occurs in many other gull species.

The setting in which the communication occurs: dominance display, courtship, predator alert, food gathering

Key Idea: Communication is the transmission of (understood) information between individuals, usually of the same species. It is essential to species survival and reproductive success. Effective communication enables animals to avoid predators, coordinate foraging and hunting activity, maintain social

Fixed action patterns and communication

Releaser or sign stimulus

Rules by which the sender must transmit the signal Code Code Signal

Context

The medium in which the signal is transmitted: visual, chemical/olfactory, tactile or auditory

Intraspecific Communication48

The red dot on the bill of the adult gull acts as a releaser for a fixed action pattern in the chick (the chick pecks at the red dot). The pecking action acts as a releaser for a fixed action pattern in the adult, in which it regurgitates food (above). The behavioural response to the sign stimulus is mediated via a neural processing system called the innate releasing mechanism. The message "I'm hungry, feed me" is therefore communicated in a unchanging way, which is recognised by both parties.

Receiver The individual who detects the signal

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Channel

Sender The individual who transmits the signal

1. Why do animals need effective communication over both long and short distances?

behaviours, and attract mates. Messages can be passed between animals using a range of signals that may be visual, chemical, auditory, or tactile. The type of signal used depends on the activity pattern and habitat of the animal, e.g. sound carries well in dense forest.

Auditory messages

Tactile messages

Olfactory messages

Many animals convey information to other members of the species through body coverings and adornment, as well as through gestures and body language. Visual displays can signal threat, show submission, attract a mate and even exert control over a social group.

Social species with dominance hierarchies (e.g. wolves) use stereotyped expressions and body postures to avoid direct conflict with others in the group. The messages are well understood and rarely challenged.

Visual messages

2.0CCartfarmer

Many animals are bioluminescent. The glow they produce can be used as a signal to others of their species, such as fireflies signalling to a mate. Some deep sea fish use bioluminescence to signal other fish in the school.

3. (a) Describe and explain the communication methods best suited to nocturnal animals in a forest habitat: (b) Describe and explain the communication methods best suited to solitary animals with large home ranges:

Some animals produce a stunning visual display to attract a mate. The plumage of some birds can be extremely colourful and elaborate, such as the peacock (above), the birds of paradise, and the lyrebird.

Sound may be used to communicate over great distances. Birds keep rivals away and advertise for mates with song. Fin whales send messages over thousands of kilometres of ocean. Calls by mammals may attract mates, keep in touch with group members or warn away competitors.

Bioluminescence

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Body position or facial expression

Touch may be part of a cooperative or an aggressive interaction. Grooming behaviour between members of a primate group communicates social bonding. Vibrations sent along a web by a male spider signal to a potential mate not to eat him.

Attraction

Some animals produce scents that are carried by the wind. Scents may advertise for a mate or warn neighbouring competitors to keep out of a territory. In some cases, mammals use their urine and faeces to mark territorial boundaries. Sniffing genitals is common among mammals.

4. Explain the role of dominant and submissive behaviours in animals with social hierarchies:

Pukeko

Key Idea: Pukekos use a range of visual displays for communication between indiviudals. Postures provide a very important form of communication between animals. The ethogram (behavioural profile) below illustrates the various postures exhibited by the pukeko (Porphyrio porphyrio), a New Zealand wetland bird. The

display Usually at end of encounter. Wings exaggerated, tail fully up. Beak held too high to peck at other bird. 12 ++ very aggressive + slightly aggressive 0 neutral slightly submissive very submissive

Range of aggressive/submissive behaviours Full bow. Submissive wings and tail fully up. 3 Move away Submissive display Wings exaggerated. Tail fully up to uncover white feathers. 8 Head flick.

pukeko has an unusual social organisation. Over 90% of the birds are communal, living and breeding together in groups of 3-12 individuals. Social behaviours are often graded from those involving overt aggression to those that are entirely submissive. Some birds almost always show submissive behaviour while others habitually show aggressive behaviour.

Ethogram for pukeko behaviour Submissive

KNOW © 1988-2016 BIOZONE International ISBN: 978-1-927309-56-8 Photocopying Prohibited 67 Crouch. Submissive display to an aggressive upright bird. 9A 9B Head flagging. Submissive display Head held low and moved from side to side. 11A 11B Horizontal forward. Aggressive display but not as aggressive as an upright. 10 Aggressive upright. Wings down. Tail horizontal. 7 Fighting. Both birds jumping with feet ready for clawing and beak open for pecking. 6A 6B Facing away. Submissive display to an aggressive upright bird. 5A 5B Fighting. One bird jumping with feet ready for clawing and beak open for pecking. 1A 1B Fighting. Both birds in aggressive uprights and using feet to attack. 4A 4B Fighting. One bird in aggressive upright posture with wings and tail raised and feet raised. The other bird is in the aggressive upright but not attacking. 2A 2B

3. What might be the purpose of graded intensity in ritualised behaviour?

1. Pukekos have a graded range of display behaviours of increasing aggression or submission. In the spaces provided, use the symbols (+, –, 0) to indicate the degree of aggressiveness, submissiveness, or neutral body language for each of the behaviours shown.

2. Why is a lot of animal communication ritualised?

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Su sunning

F feeding

GL on ground - leaf litte r

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animal's behaviour is taken at regular time intervals (e.g. every minute, on the minute). Select a time interval that suits the nature of the behaviour and the time available to you for taking the sample. It is useful for a number of people to study a group at the same time, each observing a different animal, to allow comparisons and provide a total picture of group interactions. Use the codes listed to classify the types of behaviour shown by the animal. You may wish to present the results in table and/or graph format.

TB on a tree branch

GS on ground - soil

Time:Date:

Ag aggression (e.g. fighting)

Fo floating Sw swimming

TT on a tree tr unk

Wu under water

Key Idea: Systematic recording of behaviour can help in understanding group dynamics and hierarchies. Bird species such as sparrows, ducks, hens, or seagulls are ideal subjects to observe and gather data on intraspecific social interactions, especially when resource competition is increased by feeding. Zoo animals, such as primates, also provide excellent subjects. As a means of gathering semiquantitative data about an animal's behaviour it is possible to use a record sheet. Using a watch, a 'sample' of a single

Sb submission

Season:

OS other social interaction

7. Dr (10 s)

GG on ground - grass

2019181716151413121110987654321 Behaviour chart 4039383736353433323130292827262524232221 6059585756555453525150494847464544434241

Dr drinking

G on ground

Fl flying

TL on le aves

A airbor ne

GM on ground - marsh

Species: Age and sex: Weather:

W in the water

Wl walking

Dp display (e.g. singing)

Recording Animal Behaviour

Location codes

TASK: Use your record sheet(s) to produce a report, presenting your results in a table or graph. In your discussion, focus on how the behaviours you observed might relate to the survival of the individual.

Pr preening/grooming

T in a tree

4. Defence of resources against other groups.

Unstructured social groups Structured social groups

2. Explain why group behavior, such as schooling, is more about individual advantage than group advantage:

3. Locating and obtaining food.

Possible disadvantages of large social groupings

Solitary animal

5. Division of labour amongst specialists.

Many animals form loose associations but do not interact socially. Each animal is acting for its own benefit with little or no direct cooperation between them. Schools of fish, flocks of birds, and some herding mammals exhibit this unstructured social grouping.

3. Interference with reproduction, e.g. infanticide by non-parents or cheating in parental care (as in brood parasites) so that non-parents may unknowingly raise another's offspring.

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1. Protection from adverse physical factors and predators.

Key Idea: Animals may be solitary, form loosely associated groups, or form complex groups with clear social structures. Each behaviour has its advantages and disadvantages. No animal lives completely alone. At some stage in their lives,

1. Increased competition for resources between group members as group size increases.

all animals must interact with others of their species (e.g. to reproduce or through competitive interactions for food or resources). Generally animals are classed as being solitary, in unstructured social groups, or in structured social groups.

Dominance hierarchies help distribute resources and maintain social structure. In some species (e.g. ants and bees), group members are divided into castes with specific roles. Some produce offspring or help raise young, others may be workers or help with defending the colony.

3. (a) Give two advantages of living in social groups:

7. Population regulation (e.g. breeding restricted to a dominant pair).

Solitaryindependent.lifeis

Unstructured social groups provide protection from predators by reducing the possibility of being preyed upon individually. There may also be benefits during feeding and moving.

2. Assembly for mate selection.

often an advantage when resources are scarce or scattered over a large area. Solitary animals include many of the cat family e.g. tiger (above), bears, and various invertebrates.

Some species form complex social structures, often based around a family group. Some involve dominance hierarchies in which individuals in the group are ranked socially.

Advantages of large social groupings

2. Increased chance of the spread of diseases and parasites.

(b) Give two disadvantages of living in a social group:

Solitary animals spend the majority of their lives alone, often in defended territories. They may only seek out others of their species for breeding. Offspring are often driven away shortly after they become

1. Give one advantage and one disadvantage of solitary living:

6. Richer learning environment.

WorkerSoldier

Eusocial animals are those in which a single female produces the offspring and non-reproductive individuals care for the young. They have the highest form of social organisation. Individuals are divided into different castes with specific roles. In most cases, a queen produces all the young and members of the group are normally directly related to the queen. Non-reproductive members of the group may be involved in care of the young, foraging, or defence of the nest site. Examples include ants, honey bees, termites, and naked mole rats.

Social Organisation52

2. Describe the organisation of a eusocial animal group:

Eusocial animals

PDUSDA,

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Female elephants and their offspring form small groups lead by the oldest female (the matriarch). Adult male elephants only visit the group during the reproductive season.

Key Idea: In social groups, members of the group interact regularly. Social species organise themselves in a way that divides resources and roles between group members. All behaviour has its roots in an individual's underlying genetic programme, but these innate behaviours are often modified by learning through experience, particularly social interactions. The behavioural adaptations of organisms contribute to

3. In eusocial animals, worker and soldier castes never breed but are normally all genetically related. How might their contribution to the group help pass their own genes to the next generation?

1. What is the difference between eusocial and presocial groups?

4. Elephant herds are led by a single matriarch and consist of her daughters and their calves. The matriarch leads the herd to feeding and watering grounds. How does living as a group help the survival of the herd once the matriarch dies?

Presocial animals

The number of males in a social group varies between species. In equines, a single stallion controls a group of mares. Young males are driven away when they are old enough. In elephants, the group is led by a matriarch, and the herd relies on her to make decisions in a crisis.

Termite queen

their fitness (survival and successful reproduction) and so are the products of natural selection. Many animals live in cooperative groups for all or part of their lives. Structured social species are those where individuals live together in an organised fashion and can be divided into eusocial and presocial groups. Social groups divide resources and activities between them and are mutually dependent.

ISBN: 978-1-927309-56-8

KNOW

Presocial animals exhibit more than just sexual interactions with members of the same species, but do not have all of the characteristic of eusocial animals. They may live in large groups based around a single breeding pair and relatives (e.g. aunts/older siblings) may help raise the young. These groups often form hierarchies where the breeding pair are the most dominant. There may also be separate hierarchies for male and female group members. Examples include canine species that live in packs (e.g. wolves), many primates, and some birds.

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3. What evidence is there that unrelated species can act cooperatively? Why would they do this?

Key Idea: Cooperative behaviour is where two or more individuals work together to achieve a common goal. It increases the probability of survival for all individuals involved. Cooperative behaviour involves behaviour in which two or more individuals work together to achieve a common goal such as defence, food acquisition, or rearing young. Examples include hunting as a team (e.g. wolf packs, chimpanzee hunts), responding to the actions of others with the same goal (e.g. migrating mammals), or acting to benefit

enhance

Kin selection is altruistic behavior towards relatives. In meerkats, individuals from earlier litters remain in the colony to care for new pups instead of breeding themselves. They help more often when more closely related.

One example is the black-capped chickadee, a species that often forms mixed flocks with other species. When its mobbing calls in response to a screech owl were played back, at least ten other species of small bird were attracted to the area and displayed various degrees of mobbing behaviour. The interspecific communication helps to coordinate the community anti-predator mobbing behaviour.

(b) Why would altruism be more common when individuals are related?

1. (a) What is altruism?

others (e.g. mobbing in small birds). Cooperation occurs most often between members of the same species. Altruism is an extreme form of cooperative behaviour in which one individual disadvantages itself for the benefit of another. Altruism is often seen in highly social animal groups. Most often the individual who is disadvantaged receives benefit in some non-material form (e.g. increased probability of passing genes onto the next generation).

Animals may move en masse in a coordinated way and with a common goal, as in the mass migrations of large herbivores. Risks to the individual are reduced by the group behavior.

Evidence of cooperation between species

2. How do cooperative interactions the survival of both individuals and the group they are part of?

Many small birds species will cooperate to attack a larger predatory species, such as a hawk, and drive it off. This behaviour is called mobbing. It is accompanied by mobbing calls, which can communicate the presence of a predator to other vulnerable species, which benefit from and will become involved in the mobbing.

Coordinated behavior is used by many social animals for the purpose of both attack (group hunting) and defense. Cooperation improves the likelihood of a successful outcome, e.g. a successful kill.

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Cooperative Behaviour

f therefore care-giving behaviour of sisters will increase faster than genes promoting investment in offspring.

f honeybee males (drones) are haploid and females are diploid

Kin selection explains the behaviour

f workers are more closely related to each other than they would be to their own daughters

4. (a) How does kin selection account for the evolution of apparently altruistic behaviour?

Workers: female diploid The queen's daughters will share identical genes from the father and will share half the genes from the queen.

Each female worker in the colony: f sacrifices her life to defend the colony against danger f produces no eggs f raises the young of the queen

ISBN: 978-1-927309-56-8

Honeybees: The ultimate in unselfish behaviour?

5. How are honeypot ant repletes an extreme form of cooperation?

Honeypot ants

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Are honeybees altruistic?

f workers therefore all have the same male genes and half the queen's genes

Honeypot ants of central Australia have a special group of workers called 'repletes'. These never leave the nest, but stay in underground galleries where they serve as vessels for storing a rich food supply. Regular workers that have been foraging for honeydew and nectar return to the nest where they regurgitate food from their crops to feed the replete. The replete will continue to accept these offerings until its abdomen has swollen to the size of a pea (normally it is the size of a grain of rice). The repletes become so swollen that their movements are restricted to clinging to the gallery ceiling where many hundreds of them hang in a row. When the dry season arrives and food supplies become scarce, workers return to the repletes, coaxing them to regurgitate droplets of honey.

2.5CCen.wikipediaatHumeGreg

(b) Do you think such behaviour is truly self sacrificing? Explain:

Drone: male haploid

210

White fronted bee-eaters

WhitechicksfledgedofNumberfronted

1. Describe an example to show that living in a group improves survival:

EmlenT.Stephen alet 1995

Adults in the nest 2 3 3 4 4 5 6

Relatedness 0 0.125 0.25 0.5 helpingofProbability

Gunnison's prairie dogs

bee-eaters (left) live in family groups which include a breeding pair and nonbreeding pairs. All adults help provide for the chicks. Graph 1 shows the relationship between the number of adults in the nest and the number of chicks fledged. Graph 2 shows how relatedness affects the amount of help the pairs give the chicks.

Gunnison's prairie dogs (right) live in large communities called towns in the grasslands of western North America. The towns are divided into territories which may have up to 20 individuals in them. During foraging, above-ground individuals may produce alarm calls if a predator approaches, at which nearby prairie dogs will move to cover. However, whether or not an alarm call is given depends on the relatedness of the individuals receiving the call to the individual giving it. Gunnison's prairie dogs put themselves at risk when giving an alarm call by attracting the attention of the predator.

No knownkin 6040200 Non-descendentkin(e.g.cousins) Parent / siblingsOffspring whenoccurrencesofPercentage callsalarmgaveindividuals

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2. The level of help between group members often depends on relatedness. Using the examples of the white fronted beeeaters and Gunnison's prairie dog, explain how relatedness to the helper affects the level of help given:

Key Idea: By working together (directly or indirectly) members of a group increase each other's chances of survival. However the level of help depends on the level of relatedness. Living in a group can improve the survival of individual group members, e.g. by improving foraging success or decreasing

the chances of predation. Animals such as meerkats, ground squirrels, and prairie dogs decrease the chances of predation to others by having sentries that produce alarms calls when a predator approaches. Many animals live as family groups that help with foraging and raising the young. 2

1.00.80.60.200.4

How Cooperative Behaviour Improves Survival

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(b) Describe two ways in which additional adult helpers may increase the survival prospects of pups:

4. The graph at the top of this page shows how the survival of black-backed jackal pups is influenced by the number of adult helpers in the group.

5. How can a social behaviour that is beneficial to individuals in a species become more common over time?

Black-backed jackal (Canis mesomelas) Black-backed jackals live in the brushland of Africa. Monogamous pairs (single male and female parents) hunt cooperatively, share food and defend territories. Offspring from the previous year’s litter frequently help rear their siblings by regurgitating food for the lactating mother and for the pups themselves. The pup survival results of 15 separate jackal groups are shown in the graph on the left.

Number of adults

The effect of the number of

survivingpupsofNumber

(a) Draw an approximate ‘line of best fit’ on the graph (by eye) and describe the general trend:

3. How might helping the offspring of a sibling to breeding age, instead of breeding yourself, improve chances of passing your own genes on to the next generation?

adults in the family on pup survival for black-backed jackals SOURCE: Drickamer & Vessey, Animal behavior (3rd Ed) PWS, 1992 123456 12345 0

100806040200

herding mammals. Forming groups during an attack by a predator decreases the chances of being singled out, while increasing the chances of a successful defence

3. Sheep need to spend most of their day feeding on grass. They form mobs both naturally in the wild as well as on farms.

Red colobus monkeys are a common target during chimpanzee hunts. They counter these attacks by fleeing (especially females with young), hiding, or mounting a group defence. The group defence is usually the job of the males and the more defenders there are, the greater the likelihood of the defence being successful.

(a) Explain why sheep form mobs: (b) Explain how this might enhance an individual sheep’s ability to feed:

In the Siberian steppes, which are extensive grasslands, musk oxen must find novel ways to protect themselves from predators. There is often no natural cover, so they must make their own barrier in the form of a defensive circle. When wolves (their most common predator) attack, they shield the young inside the circle. Lone animals have little chance of surviving an attack as wolves hunt in packs.

1. Describe two benefits of cooperative defence:

Attack pattern by wolves

Key Idea: Working together in defence decreases individual risk and increases the chances of a successful defence. Group defence is a key strategy for survival in social or

Young

Group defence in musk oxen

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Red colobus monkey defence

ATamari

headsCircularcentreprotectedsafelyindefencewithfacingoutwards

Number of male colobus defending 0 1 2 3 4 5 6 7 8 againstdefended

successfullyhuntschimp%

2. How many colobus males are needed to effectively guarantee a successful defence against chimpanzees?

The Gombe Chimpanzee War

Key Idea: Working together in attack can help increase the chance of success especially if roles are allocated between the attacking members.

SmithA.Adrian

Many ant species, e.g. slavemaker ants (above left), raid other ant nests (called slaveraiding), killing workers and capturing grubs. The grubs are carried back to the home nest where they grow and tend the slavemaker ants' own young. Sometimes, however, the slaves rebel and can destroy the slavemaker nest. In his book Journey of Ants Edward O. Wilson, the world's leading ant expert, noted (not wholly tongue-in-cheek) that with ants "their foreign policy can be summed up as follows: restless aggression, territorial conquest, and genocidal annihilation of neighbouring colonies wherever possible. If ants had nuclear weapons, they would probably end the world in a week."

Group attack is often used for hunting for food, but may be

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used by some species for raiding nests or territories in order to gain access to new resources (e.g. space or workers). Group attacks may be highly organised, with individuals taking specific roles.

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Group attacks between members of the same species and even the same social groups do occur. They usually involve disputes over resources or territory, but may be due simply to rifts in social groups. One of the most well recorded and startling examples of group fighting is the Gombe Chimpanzee War. Observed by Jane Goodall, the violence began in 1974, after a split in a group of chimpanzees in the Gombe Stream National Park, in Tanzania. The group divided into two, the Kasakela in the northern part of the former territory and the Kahama in the south. Over the course of four years, the Kasakela systematically destroyed the Kahama, killing all six males and one female and kidnapping three more females. The Kasakela then took over the Kahama territory. However, ironically, the territorial gains made by the Kasakela were quickly lost as their new territory bordered a larger more powerful group of chimpanzees, the Kalande. After a few violent skirmishes along this border, the Kasakela were pushed back into their former territory.

1. (a) Suggest two reasons for cooperative attacks: (b) Suggest why cooperative attacks are more likely to be successful than individual attacks: 2. Chimpanzees often hunt cooperatively. Use the data below to plot the relationship between hunting success and group size. No. hunters 1 2 3 4 5 6 Hunt success (%) 13 29 49 72 75 42

VarmaKalyan

Lionesses hunt as a coordinated group. Several lionesses hide downwind of the prey, while others circle upwind and stampede the prey towards the lionesses in wait. Group cooperation reduces the risk of injury and increases the chance of a kill. Only 15% of hunts by a solitary lioness are successful. Those hunting in a group are successful 40% of the time.

Army ants foraging

nestTemporary

Key Idea: Cooperative behaviour in gathering food increases the chances of foraging success and improves efficiencies. Cooperating to gather food can be much more efficient that finding it alone. It increases the chances of finding food or

cachesFood

Multiple advancing fronts

4. (a) Describe the advantages of reciprocal altruism in mountain caracara:

cachesFood

(b) Suggest why this a successful strategy even when birds do benefit all the time:

The mountain caracara in Peru (above) forages in groups of three or four, looking for prey hidden around rocks. Working together, the birds are able to overturn rocks far bigger than any individual could move. If a bird finds a rock that is worth turning over, it produces a high pitched call to attract the others. In most cases, only one bird (usually the initial caller) benefits from overturning the rock. However, the other birds may benefit when other rocks are overturned later (reciprocal altruism).

Single, advancingbroadfront

Through group cooperation, the tiny ants are able to subdue prey much larger than themselves, even managing to kill and devour animals such as lizards and small mammals. This would not be possible if they hunted as individuals.

Cooperative foraging in ants often involves division of labour. Leaf-cutter ants harvest parts of leaves and use them to cultivate a fungus, which they eat. Workers that tend the fungus gardens have smaller heads than the foragers, which cut and transport the leaves. Similarly, army ants have several distinct worker castes. The smaller castes collect small prey, and larger porter ants collect larger prey. The largest workers defend the nest.

1. What are the advantages of cooperative food gathering?

Worker castes in army ants

2. What conditions favour group cooperation in food gathering?

nestTemporary

3. Describe how the division of roles within ants increase the colony's success in obtaining food:

Column raider

There are two species of army ant that have quite different raiding patterns (right): Eciton hamatum whose columns go in many directions and Eciton burchelli, which is a swarm-raider, forming a broad front. Both species cache food at various points along the way.

Honeybees forage for nectar, gathering it from flowers and taking it back to the nest. If a particularly good nectar source is found, the bee will perform one of two dances when it returns to the nest. If the source is distant the bee performs the waggle dance. If the food source is very close (less than 50 m) the honeybee will perform a round dance The honeybee's round dance stimulates other workers to leave the hive and search within 50 m for a food source.

DomainPublicWildAlex

Swarm raider

capturing prey. Cooperative hunting will evolve in a species if there is a sustained benefit to the participants, the benefit for a single hunter is less than that of the benefit of hunting in a group, and cooperation within the group is guaranteed.

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Key Idea: Aggressive behaviour encompasses conflict over resources as well as predatory behaviour. Agonistic behaviour specifically refers to non-predatory competitive behaviour between conspecifics (individuals of the same species). Aggression is a complex phenomenon often associated with competition for resources, but it also includes predatory behaviour. Agonistic behaviour is a more precise term,

which refers specifically to conflict situations between members of the same species. Agonistic behaviour includes all aspects of conflict, such as threats, submissions, chases, and physical combat, but it excludes predatory aggression. Agonistic behaviour is usually highly ritualised so that it is not easily misinterpreted. The ritualisation has an important role in reducing the risk of physical conflict and injury.

DoC

(b) Ritual aggression:

Conflict Social Groups

(a) Dominance hierarchies:

Many primates and birds form dominance hierarchies established by agonistic behaviour. Once the hierarchy is in place, little effort is required to maintain order in the

Disputesgroup.between

1. Distinguish between aggressive behaviour and agonistic behaviour:

Hooker’s (New Zealand) sea lion forms breeding colonies on several sub-Antarctic islands. A bull will set up a territory on one of the breeding beaches, defend it against challenges from other bulls, and attract females as mates to the site.

Aggression can occur between different species when they are competing for the same resources. In the photograph above, vultures are competing with hyaenas for a carcass.

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2. Describe how the following behaviours reduce the risk of injury to individuals in a population:

zebra stallions can get serious. The fighting is less ritualised than in many species and the force of the kick from the hind legs can cause serious injury. Face to face fighting may also result in serious bite injuries.

Fighting between social groups (e.g chimpanzee troops) can be extremely serious, even fatal. The fighting is usually over the defence or invasion of territories and resources.

Lions live in small prides of related females and one or two males. The dominant male's position may be challenged by nomadic males. Such challenges involve serious fighting with the winner displacing the loser from the pride.

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Control of the behaviour of another member of the same species.

Briefly describe the adaptive advantage of each of the types of aggression in the table in the column provided.

Type of aggression Description Adaptive advantage

Sexual Threats and physical abuse of rivals, usually by males, to obtain or retain mates.

Parental Attacks on intruders when the young are present and threatened.

5. Infanticide occurs in lions and Indian langur monkeys, and involves killing all the infants sired by other males.

4. Explain why, in social species, aggression between conspecific groups (e.g. one group invading another's territory) is often less ritualised and more inclined to lead to injury than aggression between individuals within the same social group.

Competitive Attack on a competitor to drive it away from a resource such as food.

Exclusion of others (usually of the same species) from some physical space.

Sibling Attack by one sibling on another to exclude them from the litter/nest.

Territorial

Predatory Act of predation, possibly including cannibalism.

Anti-predatory Defensive attack by prey on predator.

Parent/offspring Disciplinary action by parent against offspring (mammals).

Dominance

(b) Explain the adaptive value of this behaviour in terms of natural selection:

(a) Describe the conditions under which this behaviour would occur:

3. Aggression is a complex phenomenon with many functions and causes. The table below provides a list of different categories of aggressive behaviour. Most of these behaviours involve conflict among members of the same species. These forms of aggression serve very different functions depending on whether they occur within or between species:

Territories

f May be large multi-purpose territories for feeding, mating, and rearing young.

f Hierarchies enable individuals to concentrate on more productive uses for their energy (e.g. raising offspring).

Hierarchies

f Determines an order of precedence for access to food, mates and breeding sites. Dominant animals have priority access to resources.

Key Idea: Members of a population compete for the same limited resources. Territories and hierarchies help to ensure that at least some individuals obtain sufficient resources. Intraspecific competition is an interaction in which individuals of the same species compete for a resource. As population numbers increase, the resources available to each individual

In scramble competition, all individuals in the population have equal access to a limited resource and many individuals may starve. This limits population growth and can tightly constrain the life cycle events of some species. Scramble competition in caterpillars

f May be linear (with pecking order) or may be complex and involve coalitions.

In some vertebrates, defended areas, called territories, enable individuals or groups to command sole access to all the resources within a defined area. Blue duck pairs occupy and defend exclusive territories in the same stretch of river year after year.

In social groups, access to resources may be determined by the social hierarchy

Escalation of threat by fighting. May involve pushing or combat using horns and antlers, biting, or kicking. Risk of injury is high. Fights may even be fatal.

Competes with members of the same species.

'Limited aggression' with threat displays at close range, sometimes with physical contact.

The outcomes of intraspecific competition

Winner possessiongainsofresources

Effects59

become fewer and intraspecific competition increases. When the demand for a resource (e.g. food, water, nest sites) exceeds supply, that resource becomes a limiting factor to further population growth. Populations respond to resource limitation by reducing population growth rate (e.g. through lower birth rates or higher mortality).

aggressionofEscalation deathorinjuryofriskIncreasing resources:LimitedFoodShelterMates

Intraspecific and its

LINK 58 WEB 59

f Territories are effective in reducing intra-specific competition, but territory defence is costly (time and energy).

Competition

A hierarchy is a ranked social order within a group.

f May be used for a single purpose (e.g. mating grounds called leks).

Territories reduce direct aggression by dividing resources between groups or individuals.

KNOW

DomainKarora-Public

within a group

accessbyreduceHierarchiesdirectaggressioncreatingorderlytoresources

f Boundaries are patrolled and marked using signals (calls, scent).

f May be held by a single animal, a breeding pair, or a group.

Contest competition in wolves

Blue duck (whio)

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Threaten from a distance using ritualised signals (such as calls and bellows) and displays.

The most dominant individuals have priority access to food, but low ranked individuals must contest the remainder and may miss out or may be forced to leave the group.

5. (a) Explain how a territory can reduce aggression between groups: (b) What are some of the costs associated with defending a territory?

6. (a) How can hierarchies reduce aggression between individuals in a social group?

1. (a) What is intraspecific competition?

(b) Why does intraspecific competition occur?

2. Explain how intraspecific competition acts to limit population size:

4. Describe two ways in which animals can reduce the intensity of intraspecific competition: (b)(a)

(b) Discuss the benefits of a hierarchical system for the group (and species) and for individuals:

3. Describe a type of aggressive behaviour that could serve each of the following purposes: (a) Territorial defence from a distance: (b) Maintenance of position in dominance hierarchy: (c) Competition for the right to mate:

During activities such as feeding, some pukeko in close contact situations may avoid contact by taking food a short distance away from the others before eating. Other members of the group (the winners), chase away losers that come too close. In any encounter between two birds there is a winner and a loser. To determine if there is a social hierarchy, it is necessary to identify each bird individually and list them on two axes in the same order (see table below). One axis is then labelled the winner and the other, the loser. Results showed that males dominate females, and older birds dominate younger birds. The social organisation of a stable group is dependent on the fact that these birds act at all times in accordance with their status. Chicks are initiated into the hierarchy at a very early age.

Key Idea: Hierarchies in social birds can be determined by identifying the winners and losers in conflict situations.

DATA 82

3. How does the organisation of the table (above right) reflect the social rank of each pukeko?

TM Social Hierarchy in Pukekos60 LINK 50 LINK 59

Pukeko No. wonNo. lost Total % Won

2. Complete the summary in the table below for the four birds:

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4. What is different about the results for L9, W3, and B6?

5. Explain what these unexpected results mean in terms of what happens when for example, B6 meets W7:

The pukeko is a relatively common New Zealand bird, typically found in swamps and marshes. In contrast to most other bird species which form mating pairs, pukeko cooperate as a group or 'commune' with coordinated activities. More than two birds will defend territory, court and copulate, lay in, incubate and defend a single nest, and feed and care for chicks. Most social animals establish a strict ranking order or hierarchy (sometimes called a pecking order) to reduce fighting between group members.

1. Circle the square on the chart (on the right) in which this context appears: pukeko W6 defeats pukeko B6.

Outcomes of 246 meetings between individual pukeko in a population of seven birds pukeko showing its white tail feathers used as a 'flag' in signalling alarm, aggression, and submission.

6. W6, 2F, and L9 are adult males and W3, L8, and B6 are adult females. Explain the relationship between sex and status in this group of pukekos:

W7W6L9L8 This material has been reproduced with kind permission of Dr. John Craig, University of Auckland. It has been modified from part of the Senior Biology Resource Unit: The Pukeko W6 2F L9 W3 L8 B6 W7 W6 2F L9 W3 L8 B6 W7 Winner Loser 121815192913 1223931 13954 3672 131113 9 6

9. Predict the probable result of

an encounter between R1 and W3:

11. Describe the of social Describe the to social

status on the outcome of interactions between members in a hierarchy: (b)

benefits

animals of having a hierarchy to control social interaction: W6 2F L9 W3 L8 B6 W7 W6 2F L9 W3 L8 B6 W7 Winner Loser R1 R1 The outcomes of encounters between a new bird (R1) and the rest of the group TM

a dot

maintenance

important

10. What factors might be in the of a stable hierarchy within the

group?

effect

birds

(a)

8. Between which two does probably

A complete stranger, a male pukeko called R1, was adopted by the group for territorial defence. The table below shows the result of the others in the group after the is by in the appropriate square.

new bird and

7. W7 is a young male. What factor, besides sex, could influence status in a group? Explain your

answer:

encounters between

rank?

immediately

adoption. Each encounter

represented

0 Tea 7

12 Cornflake MarmaladePepper VinegarSalt Coffee TeaCrisp MustardPeanut 1983CUPPrice,R.Biology,BeginningSource:

1. How many times did Salt bite Crisp?

bit the other monkeys. The monkeys were named to assist in identification. The result is the table below. An example of how to use it is as follows: Peanut bit the monkey named Coffee 26 times, but Coffee did not bite Peanut at all. 5 0 14 0 25 9 0 0 22 0 0 0 0 0 0 0 1 2 32 0 2 0 0 0 0 13 0 3 0 0 0 8 4 0 10 0 17 7 1 2 24 1 41 1

8. What type of hierarchy do these monkeys have?

0 0 Pepper 14 4 2 1

0 Vinegar 0

Monkey Hierarchy61 LINK 59 WEB 61 Peanut 13

4. Determine whether one particular monkey bit all the other monkeys (if so, which one):

6 3 27 0 Salt 0 0 10 0 0 0 18 0 0 Mustard 8

3. Arrange the monkeys in a hierarchy on the table to the right (with the dominant one at the top and the subordinate one at the bottom). Enter the frequency of the biting for each combination of monkeys. HINT: Do this in pencil to allow corrections or work it out on a piece of refill paper first.

5. Determine whether one particular monkey was bitten by all the other monkeys (if so, which one):

2. How many times did Crisp bite Salt?

0 Crisp 0 8

6. State whether there is any monkey that shows signs of challenging a more dominant monkey for a higher position in the hierarchy. If so, name the monkey:

17 0 0 Cornflake 0 0

Hierarchy of monkeys bitingdominantMost subordinateMost Most subordinate Most dominant bittenmonkeysofHierarchy

0 Coffee 26

7. Determine if there is a pattern to the frequency of biting other monkeys once the group has been placed in descending order of dominance:

Key Idea: Hierarchies in primates can be determined by identifying the winners and losers in conflict situations. In an investigation of the behaviour of ten captive monkeys, a researcher recorded the number of times each monkey

20 0 Marmalade 0 22 8

Key Idea: Dominance hierarchies help maintain social order and reduce conflict.

(b) What resources would he gain by doing this?

1. Explain how an individual baboon (regardless of its social ranking) may be more protected by being within the troop:

3. Baboons have some of the most ferocious canine teeth of all primates, and are capable of inflicting massive injuries. Explain how a dominant baboon male keeps order in his troop without maiming:

females. Females also have hierarchies but these are often based on mother-daughter relationships. Once established, hierarchies are usually maintained by gestures, facial expressions (e.g. yawning to show canine teeth), and ritual aggression. Fighting usually occurs when one male wishes to increase his status and rise in the hierarchy.

f Olive baboons (Papio anubis) live in the savannah regions of Africa and have a highly organised and complex social structure. Within a troop of baboons (see below) an orderly hierarchy promotes division of labour within the group, reduces conflict, and maximises the efficiency with the which the group can search for food and defend itself against predators and other troops.

2. Describe one feature of the social structure of the baboon troop that gives additional protection to its members:

4. (a) How might a subordinate male improve his status in the hierarchy?

Source:

AdolescentsSubordinateadultmale Female oestrousin Subordinateadultmale Dominantmale Female oestrousin withFemalesyoung Dominantmale

Baboons have a highly developed social structure with a dominance hierarchy. Dominance hierarchies are most commonly seen in males, who are usually not related and aggressively compete over higher positions and access to

Hall and De Vore, 1965 LINK 59 LINK 64 WEB 62

f The adult males are distinguished by their large size and well developed manes. Females with babies are positioned near the centre for protection. The two females in oestrus move in consort with the most dominant males. All males (with the exception of the dominant males) tend to be positioned on the edges of the group. Should any threat be encountered in their march, the dominant males will move to the front, with the subordinate males in support. The females, adolescents and babies move to the rear, away from the threat.

Territories and Home Ranges

Key Idea: Territories are defended regions, whereas home ranges are generally larger areas that are not defended. A territory is the area occupied by an animal and defended against intruders. Territories may be large and multi-purpose for feeding, mating, and rearing young, or they may be small

Overlap

1. (a) Distinguish between a territory and a home range:

Territory size depends on a many factors including resource availability, the social behaviour of the animal, and the energy expended to defend it. Gannet territories consist of the nest and the area immediately around the nest. The home range consists of the ocean covered when searching for food.

(b) Describe how the core area is similar to the territory:

A lek is an aggregation of males engaging in competitive displays. Males defend their lek territories, which are usually established seasonally. Females select mates based on their display or position in the lek. Highly ranked males occupy the middle of the group with lower ranked individuals on the periphery.

Ownership of a territory is usually continually proclaimed. Male skylarks (above) may sing for twenty minutes at a time while flying high above their territory. Maintaining a territory benefits an animal by maintaining access to a resource, e.g. a nesting site or food source.

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CollinsGraham

Nest

Lekking in greater sage grouse

LINK 64 LINK 65

and for a single purpose, e.g. mating grounds called leks. Home ranges are usually much larger that territories. They are not defended and may overlap with the home ranges of other members of the species. This means that even solitary animals can remain in contact with others.

Territories are actively defended and, once established, provide relatively undisputed access to the resources within. (e.g. food, shelter, water, nest or den site). Territories may be established by fighting and are marked by calling or using scent marks.

The home range is the area where an animal may roam but does not defend. It may overlap with several other home ranges.

The area where the animal spends most of its time is called the core area and usually contains the best resources.

2. Establishing and maintaining a territory takes time and energy. Describe its adaptive value to the organism:

Key Idea: Baboon troops occupy home ranges that overlap but have distinct core areas. Olive baboon troops in Africa each occupy distinct home ranges. The home range is the area regularly utilised by the

Sleeping trees

Scale 05

Region Home range size (km2) troopAveragesize Habitat rainfallYearly(mm) Bole Valley, Ethopia 1.1 20 Mixed forest and grassland 2000 Ishasa, Uganda 4.0 60 Forest and shrub-land 1200 Gilgil, Kenya 19.7 49 Open grassland and shrub-land 750 Laikipia Plateau, Kenya 43.8 100 Dry grassland 500 http://pin.primate.wisc.edu/factsheets/entry/olive_baboon LINK 63 LINK 65

3. The table below summarises troop size and home range size in various baboon troops in Africa. Use the information in the table to describe how the environmental factors affect the home range of baboons:

2. (a) How many home ranges are represented on the map above?

(b) Contrast the distribution of home ranges and core areas of neighbouring troops. Suggest a reason for the difference:

Baboon home ranges in Nairobi Park km boundarParky

1. Why would baboons defend the core areas aggressively?

troop, and it provides all the resources the troop needs for its survival. Home ranges differ from territories in that they may overlap in places and are not necessarily defended. The size of the home range reflects the quality of its resources.

Home Ranges and Resources in Baboons

Key Core (eachHomeareasrangesrangeshown by different dash pattern)

This map shows the boundaries of home ranges of different olive baboon troops living in the Nairobi Park, Kenya. Each has its own resident population of baboons that can range from 20-80 in number. Savannah-dwelling baboons spend more time on the ground than do most other primates and have one of the largest home ranges, averaging 20 km2. Baboons may travel up to 4 km a day in search of food. Most of the troop's activity is concentrated in the core area (which is like a territory). This area contains the best food sources, and more importantly, water holes and trees for sleeping in at night. Although olive baboons spend nearly all of their day on the ground, they always return to the safety of the trees before dusk to sleep.

Nairobi

► Falcons made the most successful hunting attempts along pine stand edges between stands less than 4 years old and more than 20 years old.

Research (Seaton, 2007) showed that the reproductive success of NZ falcons is much higher in commercial pine forests with a mix of different aged stands than in native forest. Moreover, territories in pine forests are much smaller than in native forest. This might seem surprising, but the pine forest habitat supports a large number of small bird species as prey.

Key Idea: The size of a home range on the resource density. Home ranges are larger when resources are

LINK 63 LINK 70

Explain how the defence of home ranges by the

10 to19 years

Home ranges of four adult male NZ falcons in the Kaingaroa Forest during the 2005 breeding season (August-March). Forest composition (age of pine stands) is shown in the key. During the breeding season, the entire home range is defended, making it like a large territory.

Summary facts

Pine Stand Age Class

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University.

ISBN: 978-1-927309-56-8

The New Zealand falcon or karearea is New Zealand's only endemic bird of prey. It catches its prey (mainly small birds) on the wing and rarely eats carrion (dead animals). It is aggressive and territorial, but is vulnerable to introduced predators because it nests on the ground in a simple scrape in the soil.

More than 20 years Falcon nests 2005-06

► Stands less than four years old made up the largest proportion of the falcon home ranges. Old stands provide necessary cover from which to launch attacks over the more open younger stands.

Prohibited 88

Thanks to Richard New forestry" (2007), Massey

► Prey availability is also high in open stands where prey is more vulnerable to attack.

scarce.

3. Look at the map of home ranges above. (a) What habitat feature do all the home ranges have in common that is important to karearea? (b) Where do the karearea prefer to nest? Can you suggest why? 4. On a separate page, discuss how you might manage a forest to enhance the conservation of karearea? 0 0.6 1.2 Kilometres

2 What evidence is there to suggest that pine forest habitat might be more suitable for

McDougallScott

Defended areas reduce competition

► Prey availability is enhanced in pine plantations by high densities of prey congregating along pine stand edges.

1. karearea could reduce competition for resources: karearea native forest:

than

Less than 4 years 4 to 9 years

Seaton, Wingspan Birds of Prey Trust, for use of material from his PhD thesis "The ecological requirements of the

depends

Zealand falcon (Falco novaeseelandiae) in plantation

Home Ranges in Karearea

► The home range size of falcons in the Kaingaroa pine forest (9 km2) is much smaller than the 75 km2 recorded for native forest.

3. Secondary birds do not breed. What is the adaptive advantage to them of remaining in the territory of the primary bird?

2. Compare the home range of the yellowhead with its territory:

Source: Graeme Elliott, Ecological Consultant

Yellowhead Territories

4. What is the likely cause of bird N reducing its territory by about a half in 1987-1988? Territorysite margin

Key Idea: Territories can be occupied by cooperating individuals, which help to support a breeding pair.

Yellowhead Mohoua ochrocephala

0 metres 4 (JLMHI)K (XY)QO 2 3 N C (U) AB ST (G)EF 1986-7 I J (XY)Q O 2 3 NABC ST FG M1987-8UL OPEF (G) CD W QR HI AB ST Z1 XY(JKLM) 4 1985-6 OP GW(K) QR H (IJ) EF CD V ABZ1 ST 1984-5 Bush groundOpen Key Fledgling (juvenile)X Secondary non-breeding bird(X) Member of primary pairX Nest

LINK 63 LINK 70

1. Give the approximate dimensions of an 'average' territory (see scale on diagram):

Yellowheads are endemic to New Zealand and are highly territorial in their behaviour. They are cooperative breeders, forming breeding groups that occupy a single territory each. Each group contains a primary pair that breed, and secondary birds that act as nesting helpers. Secondaries do not take part in breeding but provide additional food for the clutch. The diagrams on the right show the changes in locations of yellowhead territories and their occupants in a Fiordland beech forest (at Knobs Flat) over a four year period. The yellowheads occupied all available space and had fairly exclusive territories in which they almost always remained and did almost all their feeding. The letters and numbers are the codes for banded birds.

boundaries Codes for banded birds using X as an exampleObscured bush

The male empid fly grips on to a twig with its front legs during mating. It uses the other four legs to grip on to the female.

LINK 68 LINK 70 WEB 67

Lock and key

What is courtship?

3.0ccZweersOnno + Prey

Male hangs on

MALE FEMALE

f A potential mate may initially be attracted by a call (e.g. male frog calling). The caller (usually male) may then perform a more intricate display once the responder (usually female) arrives. In other cases the male's call and display may be the same performance.

Female empid flies are aggressive hunters, so males have to be careful about how they approach them. Ritualised courtship behaviour by the male helps him to be accepted by the female as a mate. The male's gift of food for the female pacifies her during mating and is a crucial component of mating success.

f Sometimes the male may attract a mate by offering a gift of food. This is relatively common in insects, such as empid flies (right and below). Sometimes the male himself is unwittingly the "gift of food", such as in praying mantises in which the male is invariably eaten during mating. This behaviour is also common in spiders.

Key Idea: Behaviours associated with breeding, such as courtship, are adaptations to ensure reproductive success. Many behaviours in animals, including territorial behaviour, are associated with reproduction, reflecting the importance of this event in an individual's life cycle. Most animals breed on an annual basis and show no reproductive behaviour outside the breeding season. When the breeding season occurs, reproductive signals must be given and interpreted correctly,

or the chance for successful reproduction may be missed. The short time period that most sexually reproducing animals have in which to breed creates strong selective pressure for behaviour that improves the chances of reproductive success (therefore fitness). Breeding pairs often establish territories to ensure reliable access to resources during breeding, while ritualised courtship behaviours reduce conflict between the sexes so that mating is achieved without injury.

f Courtship refers to the behaviour of animals just before, during, and just after mating. Courtship is a way for both male and female to evaluate the health, strength, and potential fitness of a possible mate.

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KNOW

Courtship is a often crucial part of breeding

behaviourCourtship gift

The male gives the female a meal (an insect wrapped up in a cocoon) to keep her occupied while he mates.

The empid flies lock the tips of their abdomens together so that the male's sperm can enter the female. If the sperm were exposed to the air, they would dry out and die.

Breeding Behaviour

f Mate choice (or intersexual selection) occurs where members of one biological sex choose mates of the other sex to mate with. Where there is mate choice, one sex competes with same-sex members and the other sex chooses. This competition often involves elaborate rituals, calls, and displays to the choosing sex.

f Females usually have more invested in offspring so their mate choice is important and they are often the choosy sex. Female preference for certain features, e.g. eyes on peacocks tail, is thought to be behind the elaborate structures and displays that have evolved in many species (e.g. peafowl, right).

Do females chose mates?

(b) Explain how female choice could lead to elaboration of structures and displays in males:

(b) Why is courtship behaviour is often ritualised, with stereotyped displays?

In birds, song is an important mechanism for attracting a mate and proclaiming ownership of a territory. The song also acts as reproductive isolating mechanism, as differences between the songs of two species enables individuals to recognise their own species and mate only with them. Kakapo are a lek species and males attempt to attract a mate to their lek (breeding territory) by producing a low frequency booming sound during the breeding season that can be heard over many kilometres of forest. When a female arrives the male begins a display in which he spreads his wings and rocks side to side.

1. (a) Why might courtship behaviour be necessary prior to mating?

2. Describe two aspects of mating behaviour in empid flies that help to ensure successful mating: (b)(a)

3. (a) Why is choosing the best mate particularly important for females?

One of the functions of courtship behaviour is to synchronise the behaviours of the male and female so that mating can occur, and to override attack or escape behaviour. Although courtship rituals may be complex, they are very stereotyped and not easily misinterpreted. Males display, usually through exaggerated physical posturing, and the females then select their mates. Courtship displays are species specific and may include ritualised behaviour such as dancing, feeding, and nest-building. Many birds may form life long bonds (e.g. albatross above) and renew these every year by displaying to each other when they arrive at breeding grounds.

(c) In some species, the female is unable to choose a mate. Elephant seal males fight for the right to mate with a female and defend a harem. Females arriving at the beach often try to avoid the harem, but with males being up to four times heavier this is difficult. How does this system ensure the offspring are likely to have the best genes?

f Reproductive effort per offspring is high.

f Moderate to substantial care of offspring.

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f Large reproductive effort put into raising offspring to a less vulnerable stage.

High percentage of offspring survive to reproductive age

f Reproductive effort per offspring is low.

f Examples: some birds, insects, and fish.

Low percentage of offspring survive to reproductive age

mortalityLow Higher risk to parents

f Rely on others to raise offspring.

Key Idea: The way in which an animal allocates its reproductive effort is part of its reproductive strategy. Effort can be expended in producing offspring or caring for them or both. Different strategies carry different costs and benefits. The reproductive effort is the amount of energy allocated to reproduction (production and care of young). Of the total reproductive effort, the amount remaining after production of the offspring can be allocated to parental care. At one

Both mammals and birds are well known for their high levels of parental care and mammals also have a high level of prenatal investment. Other vertebrates, such as some amphibians, fish, and reptiles also provide care until the offspring are capable of fending for themselves. Bird parents are required to incubate their eggs in a nest and then feed the chicks until they are independent. Although most mammals give birth to well developed offspring, they are dependent on their mother for nourishment via suckling milk, as well as learning behaviours essential to their

Few eggs or young produced

f Moderate number of offspring.

Brood parasitism is a strategy adopted by some birds, notably cuckoos and cowbirds. The brood parasite removes an egg from the nest of a host species and lays one of its own in its place. To reduce the risk of eggs being discovered and destroyed, the eggs are spread around a large number of hosts. Most avian brood parasites have short incubation times, so the egg hatches before those of the host and the imposter will eliminate all or most of the host's eggs/nestlings. The host then raises the parasite chick as if it were its own, even when the chick is larger and differs in appearance. The strategy is not without riskonly about half of the parasite's young survive.

Broadcast spawning involves no parental investment after the gametes are released.

f Large number of offspring produced.

f Reproductive effort per offspring is moderate to low.

f Risk of egg loss is mitigated by distributing eggs amongst a number of hosts.

f Examples: most birds and mammals, some fish.

f Examples: most fish, amphibians, reptiles, and invertebrates.

Many invertebrates allocate all their reproductive effort to producing offspring and there is no parental care. Broadcast spawners such as clams and corals (above), release millions of gametes into the water. Very few of the planktonic larvae will survive. This is the most common reproductive strategy in the oceans and is typical of most marine invertebrates and many fish. Many amphibians are also broadcast spawners although there are many exceptions, including New Zealand's native frogs (Leiopelma) in which the males carry the offspring on their backs.

extreme, most invertebrates expend their total reproductive effort in producing eggs and sperm and there is no parental care. At the other extreme, mammals invest heavily in a small number of offspring and the parental care cost is substantial. Between this is a continuum, with some animals adopting alternative strategies, such as brood parasitism. No strategy is necessarily 'better' than any other. They are different solutions to the problem of successful reproduction.

f Few offspring.

Mammalssurvival.havea

Little or no parental care

mortalityHigh

Many eggs or young produced

Moderate to low risk to parents

ISBN: 978-1-927309-56-8

Low risk to parents

f Reproductive effort is put into producing the offspring, not parental care.

Brood parasites

Carebynon-parents

Noparentalcare

A shiny cowbird chick is fed by its host parent, a smaller rufous collared sparrow.

High percentage of offspring survive to reproductive age

mortalityLow

92 Reproductive Strategies68

f Little of no parental care of offspring.

high level of investment in offspring before and after birth.

Parentalcare

Parental care

flowergarden.noaa.gov LINK 69 WEB 68

Moderate number of eggs produced

f Producing offspring demands enormous amount of energy and risk. In many vertebrate species, reproduction is almost entirely up to the female (males contributing only sperm) but in other species the male also provides support (e.g. by defending a territory or providing food for the female).

2.0ccSmall

f These differences in reproductive investment have been important in the evolution of mating systems, e.g. monogamy, with animals adopting strategies that maximise reproductive success in their particular physical and social environment.

3. (a) What might be the benefits of a brood parasitism strategy to the brood parasite?

f Males, on the other hand, have less invested in offspring. They produce sperm continuously and put no direct energy into the offspring until at least birth or egg laying. Potentially, males could fertilise unlimited numbers of females and so produce far more young without any additional effort.

The shining cuckoo

1. Describe the different ways in which animals can allocate their total reproductive effort:

In kaka, both parents are needed to successfully rear the chicks. Monogamy is a common mating system when biparental care is needed for offspring survival.

2. Animals with parental care protect the investment they have already made in offspring. Explain how factors in the environment (e.g. food resources and risks to young) might influence how much care is provided by each parent:

Explain how the cuckoo's strategy of parasitising the second broods of grey warblers contributes to the continuing success of the cuckoo in its niche:

The significance of reproductive investment

A New Zealand sea lion male keeps a harem of up to 25 females and their young, which he protects.

4. The shining cuckoo (Chrysococcyx lucidus) is the world's smallest cuckoo. It is a summer migrant to New Zealand, where it is a brood parasite of the much smaller grey warbler (Gerygone igata). It usually parasites second broods, arriving in New Zealand after the grey warblers have already begun breeding. The female shining cuckoo removes one host egg per nest, laying one of her own in its place. After hatching, the cuckoo chick ejects all grey warbler eggs and/or nestlings from the nest and is raised alone.

f Because the female is most heavily invested in the offspring, it is important that she has the best possible reproductive outcome each time she mates, and mate choice is critical. In general, females have a limited reproductive outcome and can only produce so many eggs or offspring in a lifetime. For example, a human female produces one egg a month for about 40 years, a maximum of ~480 eggs in a lifetime. Given that gestation and breast feeding (which suppresses ovulation) may take two years, only about 20 children can be raised in the average lifetime (the record is reportedly 69).

(b) What adaptations of the brood parasite help to maximise the success of its strategy?

In lek polygyny, females select mates from groups of males based on the quality of the male’s display or territory. After MostExamples:female.carecare.showmalesmating,frequentlynoparentalParentalislefttothemammals

LINK 68 WEB 69

Female mates with more than one male. Polyandry occurs in some mammals (cats) and birds, and in eusocial insects and mammals (mole rats).

The best or strongest male is selected for breeding. This provides the offspring with the best genes (at least from the male).

Dotted arrows represent failed attempts at mating between males (M) and females (F). Dashed outlines unmatedsurroundindividuals

seal

Polygyny

A mating system describes which males mate with which females, under which circumstances. Different mating

(b) Polyandry:

Polygynous: Elephant

Monogamy

An organised association of several males and females, and multiple mating takes place between group members. Mating activity is not equal (some males mate more often than others).

Increases genetic diversity towardsandcompetitiondecreasesandmaleformatesaggressiontheyoung.

1. Describe the adaptive value of each of the following mating systems:

Polyandry

The males may care for their own offspring. The female abandons the male, leaving them to incubate the eggs and care for the young.

(d) Monogamy:

Males control access to more than one female. Males are often territorial and may control access to females directly or by defending valuable resources.

(a) Polygyny:

Mating system and behaviour

Likely when the habitat contains survivalriskSharedorrenewablescattered,resourcesscarcenestingsites.carespreadsandimprovesofyoung.

In birds, the female forms very brief associations with males, and mates with several males in succession.

systems offer different reproductive advantages to the individuals involved and are determined in part by the social structure of the species. Each particular mating system is usually associated with a certain pattern of parental care and is closely tied to the resources available for breeding.

Photocopying Prohibited

A breeding pair forms a partnership for the breeding season or for life. Neither sex can monopolise more than one member of the other sex.

Polygynandry

Polygynandrous: Pukeko

Polyandrous: Emu

Both parents look after the species90%Examples:young.ofbird

2. What factor might be important in determining which sex cares for the young and why?

Parental care Advantages

Mating Systems and Parental Care

All contributemembersgroup to the care of the young.

In species where the males provide prenuptial gifts, females system.alsosurvivalandGeneticnutritionalgainbenefit.benefitshigheroffspringratesmayresultfromthis

Key Idea: The life histories, mating systems, and parental care behaviours of animals have evolved to maximise reproductive success in a particular environment.

Monogamous: Emperor penguin

Key Idea: Territories are not always permanent and may be established only during the breeding season. Territories are most often established in the breeding season, usually spring and summer. In autumn and winter, migratory animals leave their territories and return to winter grounds. Other animals that do not migrate may still only defend a territory during the breeding season, when the benefits of

Use examples to support the statement that the

success:

Topismiddle.areantelopes

for

found on subSaharan grasslands. They establish leks during the mating season (March to May). Studies have shown that the closer the male is to the centre of the lekking arena the larger the number of females that are mated with per day.

Lekking is a relatively common breeding behaviour. Lekking areas (arenas) often contain numerous males. In most cases the more dominant males have leks in the centre of the arena. The diagram right shows a schematic of a greater sage grouse lek arena. The most dominant (alpha) male (A) is found in the

dailymatedFemales Distance to lek centre (m) 0 0 1 1000 432 2003Durantm.Sarah&bro-jørgensenJakob BergmanMartin alet 2007 2.0CCSnake3yes4.0CCCharlesjsharp LINK 63 LINK 66 WEB 70

The speckled wood butterfly is found throughout northern Eurasia and Africa. During the breeding season, males have two breeding strategies. Dominant males defend a patch of sunlight in a wood, while others fly through the forest looking for unmated females. Studies have shown the males defending a territory have a greater chance of mating. This appears not to be because these males are more desirable per se but that they are more able to spot females flying through the sunlight than males with no sunlit patch.

1. position of territory important reproductive

territory defence are higher. Establishing a territory uses energy and effort, but the benefit is the exclusive access to resources. During the breeding season males in particular spend time defending a territory with the goal of attracting a female and reproducing. In many cases, where territories are established purely for breeding purposes, the position of the territory is often the most important factor.

Territories and Breeding Behaviour

can be

matingofProbability Non resident 0.80.70.50.40.30.20.100.6 Resident 10AmA BBB C C C EE E E E C D D D D DD Lek mating arena B

HINT: Why do hierarchies form and how do they enhance survival?

REVISE 96

Hierarchies

ISBN: 978-1-927309-56-8

HINT: How does cooperative behaviour improve survival?

Territories

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Breeding behaviour and parental care

What You Know So Far: Intraspecific Relationships

Cooperative behaviour

HINT: Distinguish between territories and home ranges. Explain the role of territories in resource acquisition and group (or pair) survival.

HINT: Explain the role of ritualisation in breeding behaviour. How is reproductive effort apportioned and what are the costs and benefits of parental care?

Meat per hunt (kg)

2 13 61 1.85 3201 3 9 78 1.61 1837 4 7 100 2.86 2494 5 1 100 3.00 2189 6 2 50 2.00 861

Net benefit per hunter (kJ)

1 30 13 1.23 4015

Number of hunters ofNumberhunts successHunting (%)

Net benefit per hunter (kJ)

Number of hunters ofNumberhunts successHunting (%) Meat per hunt (kg)

1 30 50 1.23 4245

The hunt information in table 1 (below) was gathered from chimpanzees in the Tai National Park in Ivory Coast.

The hunt information in table 2 (below) was gathered from chimpanzees in the Gombe Stream National Park in Tanzania.

Cooperative hunting in chimpanzees

2 34 29 0.82 1250

>6 10 90 9.27 5020

4 25 72 5.47 5166 5 12 75 4.65 3471 6 12 42 3.17 1851

1. Use the information in the tables to discuss the differences between the two groups of chimpanzees in the extent of cooperation and how it relates to hunting success. Your discussion should include an evaluation of the results and a justification of your main points based on the data.

3 39 49 3.12 3804

Chimpanzees benefit from cooperative hunting. Although they may hunt alone, they also form hunting groups of up to six members or more. Chimpanzee hunts differ from the cooperative hunting of most other animals in that each chimpanzee in the hunt has a specific role in the hunt, such as a blocker or ambusher. Studies of chimpanzee hunting show that different groups employ different hunting strategies.

Mean number of bystanders eating

Number of hunters Mean number of hunters eating Mean number of bystanders

1 0.7 3.5 3.0 2 1.6 3.6 2.6 3 2.5 3.6 3.0 4 2.5 2.7 2.1 5 3.5 2.7 2.3 6 4.7 2.4 2.2

Sentinel behavior in meerkats

The graphs (right) show the likelihood of female or male meerkats standing sentinel when pups are either in the burrow or outside in the sentinel's group. The scale represents a statistical measure from a large number of observations. Error bars are ± SE.

Sharing and bonding in chimpanzees

In Tai chimpanzees, hunting is a chance to form social bonds. Study the information below showing the number of chimpanzees taking part in a hunt and eating afterwards and the mean (average) number of bystanders during the hunt and eating afterwards.

2. Explain what the information is showing and discuss the reasons why this might occur:

Meerkats are highly social carnivores that live in mobs consisting of a dominant (alpha) breeding pair and up to 40 subordinate helpers of both sexes who do not normally breed but are usually related to the alpha pair. They are known for their sentinel behavior, watching for predators and giving alarm calls when they appear.

3. Discuss the evidence that meerkat sentinel behaviour is altruistic. In your answer, you should evaluate the data and justify your conclusions:

1994BoeschChristophe MalebehaviorsentinelofLikelihood 0.120.100.080.060.040.020 Pup burrowinFemale Pup groupin 0.120.100.080.060.040.020 Pup burrowin Pup groupin (2013)Clutton-BrockandSantema

CentreSouthMiddleNorth of activity

1. Chimpanzees live in family groups. Males help defend the territory from other family groups. The territories of three family groups of chimpanzees (Tai North, Tai middle, and Tai south) are shown below.

• The reasons for patrolling and defending a territory

• The difference between territories and home ranges

Discuss the territorial behaviour of the Tai chimpanzees. Your discussion should include:

• An explanation of the level of patrolling effort and encounters between the chimpanzee groups.

N 1 km

Tai chimp territories are particularly large and well supplied with food compared to other chimpanzee territories. Males from Tai North spend nearly a third of their time patrolling the territory. Tai middle chimps engage in defensive activity more often than either Tai North or Tai South.

Style Question: Territories

K Competition occurring within members of the same species.

Cooperative behaviour evolves when there is a …

ISBN: 978-1-927309-56-8

B The area habitually occupied by an animal but not necessarily defended.

E A defined area, used by an animal for a specific purpose, delineated in some way (e.g. by scent) and defended against individuals of the same species.

2. Draw lines to match up the first half and second half of the sentences below:

J Strategies (e.g. behavioural and reproductive) that favour the reproductive success of an organism's relatives, even at a cost to their own survival and/or reproduction.

I The working together of individuals in order to reach a common goal, e.g. the gain of resources to enhance survival.

agonistic behaviour

H Behaviour that acts as a prelude to mating and reproduction. It may involve a suite of visual, auditory, chemical, and postural cues.

D Social behaviour related to fighting, such as aggressive or submissive behaviours, but excluding predatory aggression.

KEY TERMS AND IDEAS: Intraspecific Relationships

A A social structure in which there is a linear or near linear ranking of individuals in the group; each animal is dominant over those below it and submissive to those above it.

Identify the type of behaviour displayed by the orcas and the adaptive value of this behaviour:

territorykinintraspecifichomedominancecourtshipcooperativecompetitioncommunicationaltruismbehaviourhierarchyrangecompetitionselection

1. Match the following words with their definitions:

Cooperation has been taken to the extreme by eusocial animals in which the majority of members of the group …

By displaying altruistic behaviour to family members, an individual can indirectly increase …

… benefits all members of that group. sustained benefit to the members of the group.

sacrifice their individual reproductive chances to ensure the collective's genes (and therefore their own genes) are passed to the next generation.

the likelihood of their own genes being passed on to the next generation.

TEST 100

4. Orcas (killer whales) hunt seal on icebergs by swimming towards the iceberg in a group at high speed before ducking under the ice causing a large wave to wash over the iceberg, knocking the seal into the sea where it can be captured.

C Interaction in which a resource is contested.

G The transmission of (understood) information between individuals of the same species. Can be by vocal, visual, or olfactory means.

3. Explain how altruistic behaviour between closely related individuals benefits the survival of all participants:

Photocopying Prohibited

Cooperative behaviour in a group …

F Behaviour in which an animal sacrifices its own well-being for the benefit of another animal. Usually evident in kin.

Micro- and macroevolution involve the same processes on different time scales. Microevolution refers to changes in the allele frequencies of populations as a result of mutation, natural selection, genetic drift, and gene flow. Macroevolution involves the formation of new species, new genera and so forth and includes large scale patterns such as adaptive radiation.

c M Demonstrate in-depth understanding of evolutionary processes leading to speciation: Use biological ideas and/or scientific evidence to explain how or why evolutionary processes leading to speciation.

c A Demonstrate understanding of evolutionary processes leading to speciation: Use biological ideas and/or scientific evidence to describe evolutionary processes leading to speciation.

c ii Comparative anatomy: homologous structures as evidence for shared ancestry and analogous structures as evidence for convergence. 133 134

c 3 Reproductive isolating mechanisms (RIMs) contributing to speciation may be temporal, ecological, behavioural, structural, and/or genetic. Geographical isolation is often a necessary precursor to reproductive isolation. 96 97 101 104103

c i Fossil evidence (including transitional fossils) and biogeography. 123- 132

ii Models for the rates of evolutionary change include punctuated equilibrium and gradualism. We see evidence for both of these models in the fossil record. 113

Achievement criteria and explanatory notes

Achievement Standard 3.5 Key

Achievement criteria for achieved, merit, and excellence

Evolutionary processes leading to speciation terms

c E Demonstrate comprehensive understanding of evolutionary processes leading to speciation: Link biological ideas and/or scientific evidence about evolutionary processes leading to speciation. This may involve justifying, relating, evaluating, comparing, contrasting, or analysing the evolutionary processes leading to speciation.

5 Scientific evidence for evolution, including examples for New Zealand's flora and fauna, could be selected from:

c 1 The four fundamental processes in evolution are mutation, gene flow, natural selection, and genetic drift. 75 - 89

absolute chronometric)(= dating) vicariancevestigialtransitionalsympatricstabilisingspeciesspeciationmechanismreproductiverelativeequilibriumpunctuatedpolyploidyphyleticnaturalmutationmolecularhomologousgeneticgenegenefossilfitnessdivergentdisruptivedirectionalconvergentcomparativecommoncoevolutionchromosomebiogeographyanalogousallopatricalleleadaptiveadaptationradiationfrequencystructuresmutationancestoranatomyevolutionselectionselectionevolutionrecordflowpooldriftstructureclockselectiongradualismdatingisolatingselectionfossilstructure

c 4 The fossil record and molecular evidence provide evidence for macroevolution: Large scale patterns of evolution include divergence (divergent evolution), adaptive radiation, coevolution, and convergence (convergent evolution). 108 112 114 119

c iii Molecular biology (DNA and protein sequence analysis including immunology). 135 137

c 2 Allopatric speciation occurs in geographically separated populations. Sympatric speciation occurs in populations within the same region (sympatric populations). 93 95 98 104

Explanatory notes: Evidence for evolution numberActivity

c iv Developmental evidence (master genes and the control of development). 138 -139

Evolutionary processes involve the following biological ideas

Explanatory notes: Evolutionary processes numberActivity

Scientific evidence for evolution comes from many disciplines

c Use examples to show how mutation is the source of all new alleles.

c Explain the importance of variation in populations as the raw material for natural selection.

Jeff Podos

c Explain ring species and their significance to our understanding of speciation.

c Describe mechanisms of reproductive isolation, distinguishing between prezygotic and postzygotic isolating mechanisms and their significance.

By the end of this section you should be able to:

c Explain how biogeography can help explain the origin and distribution of species.

c Explain adaptive radiation in which there is rapid diversification of species to fill vacant niches.

Mutation, genetic drift, natural selection, and gene flow

c Describe how natural selection sorts variation and establishes adaptive genotypes.

c Use New Zealand examples to illustrate different patterns of evolution.

c Explain what is meant by a biological species and describe the limitations of its definition.

Activities 75 92

By the end of this section you should be able to:

c Explain the molecular evidence (DNA and proteins) for the common ancestry of living organisms.

Jeff Podos

Evidence for evolution

c Describe sources of variation in populations including sexual reproduction and mutation.

Activities 93-122

c Explain how two or more species with close ecological relationships may coevolve.

Speciation and patterns of evolution

c Explain convergent evolution in which unrelated species with similar niches converge in their structure or behaviour. Explain how analogous structures arise as a result of convergence.

c Using examples, explain how differences in selection pressures can result in stabilising, directional, and disruptive selection.

Activities 123-142

c Explain the role of geographic isolation as a first step in the reproductive isolation of populations. Identify causes of geographic isolation and recognise that these can occur on different scales.

c Explain sympatric (=same place) speciation and discuss the role of polyploidy in instant speciation events in sympatric populations.

c Explain why genetic drift is more significant in small populations or those with an unrepresentative sample of alleles (e.g. as a result of the founder or bottleneck effects).

c Describe how New Zealand's geological history has influenced speciation events in New Zealand's flora and fauna.

c Describe the effect of genetic drift and gene flow on the genetic diversity of both small and large populations.

c Use examples to explain allopatric (=different place) speciation in terms of migration, geographical or ecological isolation, and adaptation leading to reproductive isolation of gene pools.

c Distinguish different patterns of evolution to include divergence, convergence, coevolution, and adaptive radiation.

By the end of this section you should be able to:

c Explain how evolutionary developmental biology (evo-devo) now provides some of the strongest evidence for the diversification of species and the evolution of novel forms.

c Explain how comparative anatomy, including homologous structures, analogous structures, and vestigial structures, help us understand evolutionary patterns and processes.

Jo Naylor cc 2.0

c Using examples, explain how the fossil record provides evidence for evolution.

c Distinguish between the punctuated equilibrium and phyletic gradualism (gradualism) models for the pace of evolutionary change (rate of speciation). Describe the evidence for each model.

c Describe stages in species formation, including how gene flow reduces as populations become increasingly isolated.

2. evolutionary

• Mate selection

Genotype

The phenotype is the product of the many complex interactions between the genotype, the environment, and the chemical tags and markers that regulate the expression of the genes (epigenetic factors).

• Independent assortment

Favour some phenotypes more than others

Each individual in the population is a 'TEST CASE' for its combination of alleles.

• Predation

Favourable phenotypes

• Disease and parasitism

(a) What is variation? (b) Identify the sources of variation in sexually reproducing organisms:

• Recombination

• Diet/nutrients • pH • Temperature

Key Idea: Variation refers to the diversity of phenotypes within a population. Variation is important in evolution because it is the raw material for selecting favourable phenotypes. Populations are groups of individuals belonging to the same species that live in the same region at the same time. They are not necessarily isolated but may make contact with other populations of the same species (as in human populations). Each individual in a population is a carrier of its

• Gene (point) mutations

Mutations

change?

Selection pressures on the phenotype will affect an individual's fitness. Selection pressures are those factors in the environment that determine whether an organism will be more or less successful at surviving and reproducing.

The Role of Variation in Populations

Phenotypes poorly suited to prevailing environment have lower fitness and produce few offspring with the unfavourable traits.

Provides the source of all new genetic information (all new

3. relates fitness:

newgeneticandRearrangementalleles).shufflingofthematerialintocombinations.Environmentalfactorsinfluence

Unfavourable phenotypes

What is the importance of variation to

the expression of the genotype in producing the phenotype.

Determines the genetic potential of an individual.

• Chromosome rearrangements

• Climatic factors

Environmental factors

Phenotype

Sexual reproduction

(a) What is meant by fitness and why is it important? (b) Define the term selection pressure and explain how it

Selection pressures

Phenotypes well-suited to the prevailing environment have better survival and greater reproductive success (i.e. higher fitness). They produce many offspring with the favourable traits.

• Wind exposure • Sunlight

• Competition

own unique combination of alleles (genotype). An individual's genotype largely determines its phenotype (appearance). Those individuals with phenotypes well suited to the current environment have a greater chance of surviving and reproducing to pass on their genes to the next generation, i.e. they will have higher fitness. Individuals with less favourable phenotypes are less likely to survive and reproduce and their genes will have a lower representation in the next generation.

• Crossing over

made.Asilent

are eliminated 1. What is a mutation? 2. Why are some mutations retained within a population and others eliminated? 3. (a) What is a silent mutation? (b) What is the potential advantage of a silent mutation being retained within a population?

Key Idea: Mutations are changes to an organism's DNA. Beneficial mutations may spread within a population but harmful mutations are not usually retained. A mutation is a permanent change to the DNA sequence of an organism. Mutations allow for new genetic material to arise and be tested within the current environmental conditions. Most mutations are harmful because they reduce fitness. They remain at low levels within a population or they are eliminated altogether. Heritable mutations that are

Original amino acid sequence

are retained,

Individual with the mutated protein mutations others

If the mutation is beneficial (increases fitness) and it is heritable (occurs in the gametes) it is selected for and retained in the population. It may become more common over severalgenerations.Ifthemutation

Mutations76 LINK 77 WEB 76 LINK 81

is harmful (reduces fitness) in the current environment it is selected against and is usually eliminated from the population.

104

beneficial (provide an advantage) may be passed on and become established within the population. Some mutations are silent, meaning they have no phenotypic effect. These may be carried in the genome and not subject to selection pressure as long as the environment stays the same. However, a change in the environment can alter selection pressure and may result in the mutation being beneficial or harmful. The effect of a mutation will always be determined by the selection pressures on the population at the time.

Mutated amino acid sequence

A mutation occurs. Mutations may arise through errors in DNA replication or (e.g.environmentalfromfactorsUVradiation).

mutation is a DNA sequence change that has no phenotypic effect. This may be because the change occurs outside a protein-coding region (in introns), because there is no change in the amino acid (due to code degeneracy), or because an amino acid has been replaced by one with the same properties. Heritable silent mutations may be carried without effect and may only be subject to selection pressure when environmental conditions change.

Some

Photocopying Prohibited

KNOW

This mutation results in a different amino acid being added to the peptide chain. It changes the protein

f Benefit: Reduces incidence of heart disease by reducing plaque build up in the arteries (atherosclerosis).

f Effect: Continued production of lactase enzyme in adults allows the milk sugar lactose (found in dairy products) to be digested.

f Mutation: Lactose tolerance/lactose persistence.

(2012).88–9722,J.DairyInt.J.et.alM.,Leonardi,fromAdapted

ability to digest lactose in adults

WEB 77

populations?

Lactose free milk allows lactose intolerant adults to consume milk without experiencing unpleasant side effects 10% 90%

many beneficial mutations have not spread through the entire human population?

f Effect: Helps remove cholesterol from the blood by transporting it to the liver. The mutation causes a change to one amino acid and increases the protein's effectiveness at transporting cholesterol by ten times.

Italy Limone Brescia Verona Lake Garda

Apolipoprotein A1-Milano mutation

f Origin: The mutation can be traced back to Limone, Italy, in 1644.

The village of Limone, Italy

2. (a) Why would the have developed in cattle-raising

are heritable, they can spread through the population. Some beneficial mutations are not very common in the human population. This is because the mutations have only been in existence for a relatively short time, so the mutations have not yet had time to become widespread.

Beneficial Mutations

f Mutation: Apolipoprotein A1-Milano (a mutation to the apolipoprotein A1 protein).

(b) What is the advantage of being able to digest lactose as an adult?

Lactose tolerance mutation

1. Explain why

f Origin: Lactose tolerance first evolved in cattle or camel-raising populations in Northern Europe, East Africa, and the Middle East around 10,000 years ago.

Key Idea: Beneficial mutations increase the fitness of the organisms that possess them, but they are relatively rare. A beneficial mutation is one that provides a selective advantage by increasing an individual's fitness. Beneficial mutations are rare relative to harmful mutations, but if they

The ability to digest lactose remains highest in populations with a long history of consuming natural milk products. For example, 95% of people of Northern European descent are lactose tolerant. In contrast only 5-10% of people from East Asia can digest lactose. Adults without lactose tolerance have adverse reactions to dairy products including abdominal cramps, diarrhoea, and vomiting.

first

Until 1932, the only way to reach the town was over steep mountains or across the lake by boat.

it:Utente:Cits

f Benefit: Adults can digest lactose and gain the nutritional benefits from consuming dairy products. The ability to digest lactose is lost as the young mammal is weaned and lactase production declines.

(b) Describe the effect of inheriting a single copy of the Hbs mutation:

Code corresponding to the 1st amino acid

Mutantsickle-shapedproduceshaemoglobinredbloodcells

106

Normal base: T Substituted base: A

Photocopying Prohibited

carriers of the sickle cell trait, but do not have the disease. Carriers (heterozygotes) usually only display symptoms when subjected to low oxygen concentrations. Under these conditions, the red blood cells take on a sickle shape. People with two copies of the Hbs mutation suffer from sickle cell disease. The disease causes many complications and results in a shortened life expectancy.

DNAqp

produceshaemoglobinNormalnormalredbloodcells

Sickle Cell Mutation

HBB gene

Normal red blood cells

The gene coding for the β-chain of haemoglobin is on chromosome 11.

People with two copies of the Hbs mutation are homozygous and have sickle cell disease. They have a reduced life expectancy and suffer from numerous health issues. Sickled cells are broken down, resulting in low haemoglobin levels and reduced oxygen transport, so sufferers are tired and short of breath. Sickled cells can also become stuck in blood vessels and can block oxygen transport to organs and tissues.

1. What effect does the Hbs mutation have on haemoglobin?

First base

Sickle cell disease is an inherited blood disorder caused by a gene mutation (Hbs), which produces a faulty β-chain haemoglobin protein. People with one copy of the gene are

The mutated form of haemoglobin has reduced solubility and precipitates when deprived of oxygen. This deforms the red blood cells giving them a rigid sickle shape, which prevents their movement through capillaries.

A functional haemoglobin molecule is made up of two α-chains and two β-chains.

Sickle cell trait

Sickle cell disease

Sickle cells

LINK 79 WEB 78

The HBB Gene

This sequence is the beginning of the DNA template strand for a normal β-chain of haemoglobin (excluding start sequence TAC). The sickle cell mutation involves the substitution of one base for another in the HBB gene, causing one amino acid to be altered. This new amino acid is hydrophobic rather than hydrophilic, which makes the Hb collapse in on itself when deprived of oxygen.

2. (a) Describe the effect of inheriting two copies of the Hbs mutation:

β haemoglobin-chain

People with one copy of the Hbs mutation are heterozgous for the trait. The Hbs mutation is codominant (both alleles are equally expressed) so both normal and abnormal haemoglobin is produced. People with sickle cell trait usually do not suffer any complications.

Key Idea: A point mutation to the HBB gene causes the production of an abnormal haemoglobin molecule. Two copies of the mutation must be inherited for a person to have sickle cell disease.

Each red blood cell (RBC) contains about 270 million haemoglobin molecules. In their normal state, the red blood cells have a flattened disc shape which allows them to squeeze through capillaries to offload their oxygen to tissues.

1. Why do carriers of the Hbs allele have an advantage in malaria-prone regions?

Areas affected by falciparum

HbsHbs

All cells are sickled Sickle cell disease

This is a special case of balanced polymorphism, called a balanced lethal system because neither of the homozygotes produces a phenotype that survives, but the heterozygote is viable.

Sickle cell disease is caused by a mutation in a gene encoding haemoglobin. Genetic analyses show that the mutation arose spontaneously in different regions. The mutant allele (HbS) produces a form of haemoglobin that differs from the functional form by just one amino acid in the b-chain. This small change causes 'sickling' of the red blood cells. The sickling causes the red blood cells to clump together, blocking blood vessels, and causing numerous circulatory and organ problems. Destruction of the red blood cells also leads to anaemia.

All red blood cells normal Susceptible to malaria

1%5%10%malaria-20%-10%-5%

Anopheles mosquito, the insect vector responsible for spreading Plasmodium

below, susceptibility to malaria is high in the homozygous dominant condition, but lower in the heterozygous condition. Consequently, the heterozygote has a higher fitness in malaria-prone regions. Heterozygous advantage can result in the stable coexistence of different phenotypes in a population (a state called balanced polymorphism) and can account for the persistence of detrimental alleles. The maintenance of the sickle cell mutation in malaria-prone regions is one of the few well documented examples in which the evidence for heterozygous advantage is conclusive.

Fig. 1: Incidence of falciparum malaria

f In heterozygotes (HbSHb), there is a mixture of both normal and sickle cells and they are said to carry the sickle cell trait. They are generally unaffected by the disease except in low oxygen environments.

Normal and sickle cells Malaria resistance

Fig. 2: Frequency of the sickle cell allele

Four species of Plasmodium cause malaria but the variety caused by P. falciparum is the most severe.

The sickle cell allele (HbS)

Advantage79 LINK 78 WEB 79

HbHb

f People with two HbS genes (HbSHbS) suffer severe illness and often die prematurely. HbS is therefore considered to be a lethal allele.

Key Idea: Heterozygous advantage is a phenomenon in which the heterozygote has a greater fitness than either of the homozygotes in certain selective environments. Natural selection operates on phenotypes (and therefore their genotypes) in the prevailing environment. For some phenotypic conditions controlled by a single gene with two alleles, a heterozygote (an individual with two different alleles for a gene) may have a higher fitness than either of the homozygous conditions. This situation is called heterozygous advantage. In the case of the sickle cell allele outlined

Heterozygous advantage in malarial regions

Falciparum malaria is widely distributed throughout central Africa, the Mediterranean, Middle East, and tropical and semi-tropical Asia (Fig. 1). It is transmitted by the Anopheles mosquito, which spreads the protozoan Plasmodium falciparum from person to person as it feeds on blood. Symptoms appear 1-2 weeks after being bitten, and include headache, shaking, chills, and fever. Falciparum malaria is more severe than other forms of malaria, with high fever, convulsions, and coma. Death can occur within days of the first symptoms appearing.

HbsHb

Heterozygous

The paradox: The HbS allele offers considerable protection against malaria. Sickle cells have low potassium levels, which causes Plasmodium parasites inside these cells to die. Those with a normal phenotype are very susceptible to malaria, but heterozygotes (HbSHb) are much less so. This situation, called heterozygous advantage, has resulted in the HbS allele being present in moderately high frequencies in parts of Africa and Asia despite its harmful effects (Fig. 2).

3. (a) Describe the distribution of malaria throughout the world (Fig. 1):

4. Account for the distribution of red blood cell abnormalities, explaining why these abnormalities persist:

HbSHbEHbCThalassaemia

Fig. 3: Distribution: of abnormal blood conditions

Figure 3 shows the general distributions of various haemoglobin disorders that all produce abnormal red blood cells to some degree.

HbE is a mutation that appears to have arisen about 5000 years ago and is caused by a change in the 26th amino acid in the b-chain from glutamic acid to lysine.

Thalassaemia is a disease in which gene mutations result in the lowered production of haemoglobin and red blood cells. The effects can be very severe.

(b) What do you notice about its distribution compared to the frequency of the Hbs allele (Fig. 2)?

HbC is a mutation that occurs in the same position as HbS, but the mutation produces the amino acid lysine instead of valine.

2. With respect to the sickle cell allele, explain how heterozygous advantage can lead to balanced polymorphism:

The HbS mutation changes the 6th amino acid from glutamic acid to valine.

Photocopying Prohibited

Both HbE and HbC heterozygotes show virtually no (and certainly much less than HbS) symptoms of anaemia (reduced haemoglobin levels).

Gene Duplication and Evolution

Key Idea: Gene duplication can provide new copies of genes for natural selection to act on. The duplication of whole segments of DNA containing genes is called gene duplication. Gene duplication is important in evolution because it produces more genetic variation for selection pressures to act upon. Like mutations, not all gene duplications become fixed in a population and only

duplicationBefore duplicationAfter regioncontainingGene regionDuplicated

Haemoglobin:

the role of gene duplication and mutation

f In the case of genes that produce proteins with a tendency or ability to perform two functions, there may be adaptive conflict, in which its ability to perform one function compromises its ability to perform another. Gene duplication solves this problem by allowing natural selection to act on the genes so that they follow different evolutionary paths.

Gene duplication

those providing an advantage become established. Once established the gene may evolve to have a completely different role from the original gene. Gene duplication is very common and has occurred in virtually every species and often more than once. Many crop plants (e.g. kiwifruit) have duplicated not just one gene, but their entire genome. In humans, 38% of our genes have been duplicated.

f Sometimes having two genes with the same role (functionality) can be an advantage and both genes retain their original function. For example, when there is a high demand for a particular protein.

f Unless two copies of the same gene provide an advantage, one of the duplicated genes may develop a new function while the other copy continues on with its original function.

In Drosophila melanogaster, the fruit fly, 41% of the genes are duplicated

f The globin proteins are a family of iron-containing oxygen binding proteins. The evolution of human haemoglobin genes has involved both duplication and mutation.

f Duplication of an ancestral globin gene (1), followed by an accumulation of mutations to both copies (2) produce the a- and b-haemoglobin genes. This was a significant event because it allowed for the formation of the large mutliunit haemoglobin protein from the different subunits (a- and b-globins).

f Myoglobin, another globin gene, was also formed by duplication, mutation, and transposition. Myoglobin has an oxygen storage role in muscle and the gene is found on chromosome 22.

f The third event was the transposition (change in position) of these genes to different chromosomes (3). Further duplications and mutations produced the wide family of globin proteins found in humans (4).

2004008000 globinAncestralgene α β α ζ ζ ψζ ψα2 ψθ ψβ δβ βG γ A γψε α1 α2 α1 α α γ β β α-globin gene family is found on chromosome 16 agoyearsofMillions β-globin gene family is found on chromosome 11

1. What is meant by gene duplication: 2. What evidence do we have that gene duplication is a common occurrence? LINK 75 WEB 80

2.0CCGART

6. What evidence do we have that the AFPIII protein found in Antarctic eelpout may be have evolved through a duplication of the SAS gene?

Photocopying Prohibited

Gene duplication in colobine monkeys has enabled the production of enzymes that optimally perform similar functions in different body environments. The primary food source of colobines, unlike most other primates, is leaves. The leaves are fermented in the gut by bacteria, which are then digested with the assistance of an enzyme produced by RNase genes. In colobines there are two forms of the RNase genes, RNase1 and RNase1B, while in other primates there is only RNase1.

AFP III protein and SAS protein have similar structures and can be modified to have similar functions. This provides evidence for the likelihood of diversification of function after gene duplication.

Molecular studies have found that a slight modification to the SAS gene causes the production and secretion of AFP III protein. Importantly, the SAS gene product shows ice binding capability. It appears that duplication of the SAS gene produced a new gene that was selected for its ice binding capabilities and diverged to become the AFP III gene in Antarctic eelpout.

Fish living in the near freezing waters of the Antarctic must have a way of ensuring their blood remains ice free. In many species, this is done by producing proteins with antifreeze properties. There are four major antifreeze proteins used by fish (called AFP types I - IV). The gene for the protein AFP III, found in Antarctic eelpout, is very similar to the gene that produces sialic acid synthase (SAS) (also found in humans).

5. Outline how a number of different globin proteins have been produced from a single ancestral globin gene:

Gene duplication in Antarctic fish

(b) Explain what opportunity could be provided by a gene duplication event in an new environment:

AFP proteinIII

ISBN: 978-1-927309-56-8

3. (a) Why aren't all gene duplications retained in a population?

Gene duplication in colobine monkeys

4. When would it be an advantage to have two genes performing the same function?

The optimal pH for the enzyme RNase1 is 7.4. For RNase1B, the optimal pH is 6.3. In colobine monkeys, the pH of the digestive system is 6-7, but in other primates it is 7.4-8. RNase1B is six times more efficient at degrading RNA in the gut of colobines than RNase1. RNase1 is also expressed in cells outside the digestive system where it degrades double stranded RNA and may assist in defense against viral infection. RNase1B is 300 times less efficient at this function.

LINK 76 LINK 82 LINK 84 WEB 81

Emigration

An Introduction to Evolutionary Processes

For example, black ladybirds are more easily seen by birds and are eaten more often than the other phenotypes. The lighter phenotypes become more common in the next generation.

Genetic variation refers to the number of different types of alleles in a population. Genetic variation produces phenotypic variation (e.g. colour of ladybirds). It is this phenotypic variation that is the raw material for natural selection.

that provides the raw material for evolution. Four processes act to cause genetic change in populations. Mutation creates new alleles and alleles may also enter or leave a population through gene flow (migration). Natural selection sorts variation and establishes adaptive phenotypes and is a major agent of evolution. Genetic drift alters alleles frequencies randomly and its effects are due to chance events. Increasingly, genetic drift is being recognised as an important agent of change, especially in small populations.

1. Define the following terms: (a) Gene flow: (b) Genetic drift: (c) Natural selection:

Migration is the movement of individuals into and out of a population. Through immigration or emigration, alleles can enter or leave the population. Gene flow tends to decrease the genetic differences between populations because alleles are being exchanged.

Key Idea: Mutations, gene flow, genetic drift, and natural selection all contribute to changes in the genetic makeup (frequency of different alleles) of a population. A population can be regarded as a collection of all its alleles (the gene pool). Changes in the frequency of these alleles in the population over time is what we call evolution. If all the organisms in a population were identical in genotype and phenotype, mutation would be the only factor affecting allele frequencies. Of course, organisms show variation and it is this

Immigration

Natural selection

As we have seen in earlier activities, genetic variation arises through mutations and the recombination of alleles through sexual Forreproduction.example, a mutation produces a ladybird with a new spotted phenotype (below).

In the example above several black lady birds have left and some very pale lady birds have arrived changing the proportion of remaining phenotypes in the population.

Genetic variation

Migration (gene flow)

For example, falling rocks kill a number of ladybirds, but more of the dark blue ladybirds, which have congregated in one area, are crushed than any other phenotype. The proportion of dark blue ladybirds remaining in the population is drastically reduced, and their representation in the next generation is also reduced.

Natural selection is the process where selection pressures act on populations to maintain favourable phenotypes and unfavourable phenotypes are selected against. Over time, favourable phenotypes become more common in the population because the individuals reproduce.

X X

This ladybird population has five different phenotypes (black, dark blue, medium blue, light blue, and pale).

Genetic drift

Genetic drift is the change in a population's allele frequency due to random events. Genetic drift has a more pronounced effect in small populations.

No gene flow flow

2. One of the important theoretical concepts in population genetics is that of genetic equilibrium, which state that "for a large, randomly mating population, allele frequencies do not change from generation to generation". If allele frequencies in a population are to remain unchanged, all of the following criteria must be met: the population must be large, there must be no mutation or gene flow, mating must be random, and there must be no natural selection. Evolution is a consequence of few if any of these conditions ever being met in natural populations. For each of the five factors (a-e) below, describe how and why each would affect the allele frequency in a gene pool. Use the diagrams to help you.

Random mating

Factors favouring gene pool change (evolution)

Natural

No natural selection selection

Mutations

112 © 1988-2016 BIOZONE International ISBN: 978-1-927309-56-8 Photocopying Prohibited (a) Population size: (b) Mate selection: (c) Gene flow: (d) Mutation: (e) Natural selection: 3. Identify a factor that tends to: (a) Increase genetic variation in populations: (b) Decrease genetic variation in populations: AA aa Aa Aa Aa Aa Aa aa aa aa AA AA AA AA AA Aa Aa Aa Aa Aa AA aa Aa Aa AaAa Aa aa AA AA AA AA AaAA Aa Aa Aa Aa aa AaAaAA aaAa aa Barrier to gene flow aaAA Aa Aa Aa Aa Aa aa aa aa AA aa AA AA AA Aa Aa Aa Aa AA Aa Aa aa AA AA Aa Aa Aa Immigration Emigration AA Aa Aa Aa Aa Aa aa aa aa AAAA AA Aa Aa Aa AA aaAa aa AA Aa Aa aa AA AA Aa Aa Aa AA aa Aa Aa Aa Aa Aa aa aa aa AA AA AAAA AaAA Aa Aa Aa Aa AA aa a'a AaAa Aa Aa aa aa aa AA AA AA AA AA Aa Aa AaAa Aa allelerecessiveNew AA Aaaa Aa AaAa Aa aa aa aa AA AA AA AA AaAA Aa AaAa Aa Aa Aa Aa AaAa aa Aa Aa Aa Aa Aa Aa Aa Aa Aa Aa Aa Aa Aa aa aa aa aa AA Aa aa AA AA Aa Aa Aa AA aa AA aa aa aa Aa aa Aa AA Aa AAAA AA aa AA aa aa aa Aa aa Aa AA Aa AA AA

Large population population

Small

Gene

Factors favouring gene stability (no evolution)

Assortative mating

pool

No mutation

0 0 20 20 40 40 60 60 Generations80 (%)frequencyAllele 80 100 100 120 140 Population 2000 Population 200 Population 20 Allele lost LINK 81 WEB 82

(delete one):

Genetic Drift Affects Gene Pools

generally the result of the founder effect or a genetic bottleneck. In the founder effect, a small proportion of the population becomes isolated, e.g. through a colonisation event. Genetic bottlenecks occur when populations experience catastrophic losses so that only a small proportion of the population survives. Both these mechanisms are well documented in natural populations. In these small populations, genetic drift is an important agent of genetic change.

Key Idea: Genetic drift is the change in allele frequencies in a population as a result of random events. It can be an important agent of evolution in small populations. Genetic drift is the change in allele frequencies in a population due to random (chance) events. It may result in the loss (or fixation) of any allele, including beneficial ones. Genetic drift is effectively sampling error so its effects are greater when the population is small. In natural systems, small populations are

(b)

In the example above, the grey marbles are becoming less frequent within the population and the amount of genetic variation within the population is reducing. Unless the proportion of grey marbles increases, it will eventually be lost from the population altogether and the allele for the blue marble becomes fixed (the only variant).

Genetic drift in a small population would increase / decrease

The graph on the right shows the effect of genetic drift on populations of various sizes. Fluctuations are minimal for a large population (2000) but more pronounced in smaller populations (200 and 20), which may lose alleles.

How could this affect a population's long term viability?

In small populations, genetic drift can be a major agent of rapid change because the loss of any one individual represents a greater proportion of the total population.

The change in allele frequencies within a population through genetic drift is often illustrated using the random sampling of marbles from a jar. The diagram below represents a population of 20 individuals. The different alleles are represented by blue and grey marbles. The starting population contains an equal number of blue and grey marbles. Random mating is represented by selecting 10 marbles at random. Twenty marbles representing the new allele proportions are placed into a new jar to represent the second generation, and the process is repeated for subsequent generations.

If environmental conditions change so that the blue allele becomes detrimental, the population may become extinct (the potentially adaptive grey allele has been lost).

(a) Describe the effects of genetic drift: (b) Explain why the effects of genetic drift are more significant in small populations?

How does genetic drift reduce variation in populations?

2. (a) the number of heterozygotes

populationStarting generationSecond generationThird generationFourth50 : 50 60 : 40 70: 30 90: 10 Draw64 Draw73 Draw91

Behavioural adaptations

Proto-kaka

Habitat

f Strong fliers, can weave between trees.

Keabranches.areinquisitive and

f Robust body for surviving in the cold.

A brush tongue to remove nectar from flowers. Strong, broad beak used for tree climbing, digging out insects, and opening kauri cones to obtain the seeds.

f Seasonal specialists, exploiting different food sources as they become available.

f Excellent vision and can identify and process a wide variety of foods, including plants, insect larvae, birds, carrion, mammals (including sheep), and human scraps.

1. What is adaptation? 2. What event resulted in the kea and the kaka diverging and what was its effect? 3. Describe how the adaptations of kea and kaka help them exploit the foods available in two very different environments: WEB 83 Rosinocc2.0MattBinnscc2.0 2.0ccDeuxmontPetit LINK 75

Physiological adaptations

114

Structural adaptations

ISBN: 978-1-927309-56-8

Physiological adaptations

Photocopying Prohibited

exposed throughout the course of their evolution. Traits that are not helpful to survival and reproduction will not be favoured and will be lost. Adaptations may be structural (morphological), physiological, or behavioural. The speciation of two New Zealand parrots, the kea and kaka, from a common ancestor illustrates the importance of adaptation to a particular habitat and niche.

Structural adaptations

f Strong, agile feet are used to hold food and to cling onto branches while feeding.

Habitat f Alpine (mountain) regions in the South Island.

f Will congregate at abundant food sources or forage alone.

Behavioural adaptations

Name: Kea (Nestor notabilis)

highly intelligent. They have been filmed using tools and are adept at problem solving.

f Dense plumage provides insulation against the cold.

f Excellent vision and can identify and process a wide range of foods including seeds, fruits and berries, flowers, buds, nectar, honeydew, and invertebrates.

Name: Kaka (Nestor meridionalis)

f Large, narrow curved beak and claws for manipulating foods, and to move and investigate objects.

Kaka uses its claws and beak to manipulate food and climb through the

Adaptation and Fitness

The kea and kaka diverged from a common proto-kaka ancestor about 3 mya. The rise of the Southern Alps provided a new alpine habitat that the ancestral kea occupied. The kaka ancestor remained in forested areas.

Forest-dwelling, found throughout New Zealand in localised forest strongholds. More arboreal than kea.

f Produce a second clutch in a season if food is abundant.

f Highly social, intelligent, and curious (characteristics useful in investigating and exploiting new food sources).

Key Idea: An adaptation is any heritable trait that equips an organism for its functional role in the environment (its niche). An adaptation is any heritable characteristic (trait) that equips an organism for its niche, enhancing its exploitation of the environment and contributing to its survival and successful reproduction (fitness). The adaptations that evolve in species are the result of the selection pressures to which they are

Retained Retained

Increasing bir th weight

Frequency Retained

EliminatedIncreasing

pigmentation

Increasing pigmentation

Stabilising selection

Key Idea: Natural selection is responsible for the differential survival of some phenotypes (and genotypes) over others. It is an important cause of genetic change in populations. Natural selection operates on the phenotypes of individuals, produced by their particular combinations of alleles. It results in the differential survival of some genotypes over others. As a result, organisms with phenotypes most suited to the prevailing environment are more likely to survive and breed than those with less suited phenotypes. Favourable phenotypes will

The adaptive phenotype is shifted in one direction and one phenotype is favoured over others. Directional selection was observed in peppered moths in England during the Industrial Revolution when soot-covered trees were common. In England’s current environment, the selection pressures on the moths are more balanced, although lighter morphs predominate. Selection will be directional when there is a trend in environmental conditions, e.g. warm to cold.

Two peaks Frequency

Eliminated Eliminated

become relatively more numerous and than unfavourable phenotypes. Over time, natural selection may lead to a permanent change in the genetic makeup of a population. Natural selection is always linked to phenotypic suitability in the prevailing environment so it is a dynamic process. It may favour existing phenotypes or shift the phenotypic median, as is shown in the diagrams below. The top row of diagrams below represents the population phenotypic spread before selection, and the bottom row the spread afterwards.

Increasing beak size

Frequency

Natural Selection Affects Gene Pools

Directional selection

Increasing bir th weight

Frequency

Frequency Retained

Increasing beak size Frequency

Extreme variations are selected against and the middle range (most common) phenotypes are retained in greater numbers. Stabilising selection results in decreased variation for the phenotypic character involved. This type of selection operates most of the time in most populations and acts to prevent divergence from the adaptive phenotype, e.g. birth weight of human infants. Stabilising selection predominates when environments are stable.

Disruptive selection favours two phenotypic extremes at the expense of intermediate forms. During a prolonged drought on Santa Cruz Island in the Galápagos, it resulted in a population of ground finches that was bimodal for beak size. Competition for the usual medium-sized seed sources was so intense that selection favoured birds able to exploit either small or large seeds. Disruptive selection may occur when environments or resources are fluctuating or distinctly divergent.

84 LINK 85 WEB 84 1. Define the following, including a statement about the type of environment that favours each: (a) Stabilising selection: (b) Directional selection: (c) Disruptive selection: 2. Explain why fluctuating (as opposed to stable) environments favour disruptive (diversifying) selection: LINK 88 LINK 86

Disruptive selection

Eliminated

Key Idea: Stabilising selection operates to keep human birth weight within relatively narrow constraints. Selection pressures operate on populations in such a way as to reduce mortality. For humans, selection pressures act to

Source: Biology: The Unity & Diversity of Life (4th ed), by Starr and Taggart

Prohibited 116

Photocopying

1. Describe the shape of the histogram for birth weights:

5. How might modern medical intervention during pregnancy and childbirth have altered these selection pressures?

1.5 30 2.0 12 2.5 4 3.0 3 3.5 2 4.0 3 4.5 7 5.0 15 100

Step 1: For this activity, you will need a sample of 100 birth weights. You can search birth records online or use the data provided in the appendix at the back of this book

Stabilising Selection for Human Birth Weight

Step 2: Group the weights into each of the 12 weight classes indicated on the graph template provided. Calculate the percentage in each weight class.

Step 3: Graph these in the form of a histogram for the 12 weight classes (use the graphing grid provided right). Be sure to use the scale provided on the left vertical (y) axis.

Step 4: Create a plot of percentage mortality of newborns in relation to their birth weight. Use the scale on the right y axis and data provided (below). Draw a line of best fit through the points.

Bir th weight (kg)

talitPercentmory 6.01.5 2.5 3.5 4.5 5.50.0 5040302010 806040200

4. Describe the selection pressures that are operating to control the range of birth weight:

Weight (kg) Mor tality (%) 1.0 80

1.0 80 1.5 30 2.0 12 2.5 4 3.0 3 3.5 2 4.0 3 4.5 7 5.0 15

The size of the baby and the diameter and shape of the birth canal are the two crucial factors in determining whether a normal delivery is possible.

85 LINK 84

Evidence indicates that the phenotypic norm is shifting. Researchers estimate that cases where the baby cannot fit down the birth canal have increased from 30/1000 in the 1960s to 36/1000 births today, indicating that there is less selection against women with narrow pelvises and babies with larger heads.

constrain birth weight to within narrow limits. This is a good example of stabilising selection. It is possible to document this effect by plotting birth weights for a large sample of the population. Carry out the steps below.

Weight (kg) Mortality (%)

2. What is the optimum birth weight in terms of the lowest newborn mortality?

Mor tality of newborn babies related to bir th weight

3. Describe the relationship between newborn mortality and birth weight:

0 sampledthsbirofcentagePer 1.0 2.0 3.0 4.0 5.00.5

Museum collections of the peppered moth over the last 150 years show a marked change in the frequency of the melanic form (above right). Moths collected in 1850, prior to the major onset of the Industrial Revolution in England, were mostly the grey form (above left). Fifty years later the frequency of the darker melanic forms had increased.

Directional Selection in Moths

Frequency of melanic peppered moth related to reduced air pollution 1960 1965 1970 1975 1980 1985 Year 1009080706050 050100150formelanicofFrequencym of betulariaBiston )(% 40 Summersmoke Winterdioxidesulfur dioxidesulfurwinterorsmokeSummer ( µ -3mg)Melanic Biston betularia

In the 1940s and 1950s, coal burning was still at intense levels around the industrial centres of Manchester and Liverpool. During this time, the melanic form of the moth was still very dominant. In the rural areas further south and west of these industrial centres, the occurrence of the grey form increased dramatically. With the decline of coal burning factories and the introduction of the Clean Air Act in cities, air quality improved between 1960 and 1980. Sulfur dioxide and smoke levels dropped to a fraction of their previous levels. This coincided with a sharp fall in the relative numbers of melanic moths (right).

Olaf

Melanic form Genotype: MM or Mm

Key Idea: Selection pressures on the peppered moth during the Industrial Revolution shifted the common phenotype from the grey form to the melanic (dark) form. Genetically determined melanism is a common polymorphism in animals (meaning different forms exist in the population). In the peppered moth (Biston betularia) during the Industrial

3. Describe the relationship between allele frequency and phenotype frequency:

2. Describe how the selection pressure on the grey form has changed with change in environment over the last 150 years:

The peppered moth, Biston betularia, has two forms: a grey mottled form, and a dark melanic form. During the Industrial Revolution, the relative abundance of the two forms changed to favour the dark form. The change was thought to be the result of selective predation by birds. It was proposed that the grey form was more visible to birds in industrial areas where the trees were dark. As a result, birds preyed upon them more often, resulting in higher numbers of the dark form surviving.

86 LINK 84 WEB 86

1. The populations of peppered moth in England have undergone changes in the frequency of an obvious phenotypic character over the last 150 years. What is the phenotypic character?

Olaf Leillinger

The gene controlling colour in the peppered moth, is located on a single locus. The allele for the melanic (dark) form (M) is dominant over the allele for the grey (light) form (m).

4. The level of pollution dropped around Manchester and Liverpool between 1960 and 1985. How did the frequency of the darker melanic form change during this period?

Revolution, selection favoured the proliferation of dark (melanic) forms over the pale (non-melanic) forms. Intensive coal burning during this time caused trees to become dark with soot, offering melanic forms greater camouflage against predatory birds. The shift in phenotype at this time is an example of directional selection.

Leillinger

Grey form Genotype: mm

(a) On the left hand grid draw side-by-side histograms for the number of 1976 birds per beak depth and the number of 1978 survivors per beak depth.

Finches87

Photocopying Prohibited

Key Idea: The effect of natural selection on a population can be verified by making quantitative measurements of phenotypic traits.

2. (a) Mark the approximate mean beak depth on the graphs of the 1976 beak depths and the 1978 offspring. (b) How much has the average moved from 1976 to 1978?

more offspring, increasing the proportion of the genes corresponding to that phenotype in the next generation. Numerous studies on both vertebrate and invertebrate populations have shown that natural selection can cause phenotypic changes in a population relatively quickly.

LINK 84 WEB 87

Numberofbirds 7.30-7.79 2 7.80-8.29 2 8.30-8.79 5 8.80-9.29 21 9.30-9.79 34 9.80-10.29 37 10.30-10.79 19 10-80-11.29 15 11.30+ 2

3. The 1976 drought resulted in plants dying back and not producing seed. Based on the graphs, what can you say about competition between the birds for the remaining seeds, i.e. in what order were the seeds probably used up?

Natural selection acts on the phenotypes of a population. Individuals with phenotypes that increase their fitness produce

(b) On the right hand grid draw a histogram of the beak depths of the offspring of the 1978 survivors.

118

Directional Selection in Darwin's

1. Use the data above to draw two separate sets of histograms:

Seal

Beak(mm)depth No.birds1976 No. survivors1978 7.30-7.79 1 0 7.80-8.29 12 1 8.30-8.79 30 3 8.80-9.29 47 3 9.30-9.79 45 6 9.80-10.29 40 9 10.30-10.79 25 10 10.80-11.29 3 1 11.30+ 0 0

The finches on the Galápagos island (Darwin's finches) are famous in that they are commonly used as examples of how evolution produces new species. In this activity you will analyse data from the measurement of beak depths of the medium ground finch (Geospiza fortis) on the island of Daphne Major near the centre of the Galápagos Islands. The measurements were taken in 1976 before a major drought hit the island and in 1978 after the drought (survivors and survivors' offspring).

Beak depth of offspring (mm)

drought on Santa Cruz Island showed how disruptive selection can change the distribution of genotypes in a population. During the drought, large and small seeds were more abundant than the preferred intermediate seed size.

Higher fitness

A 2007 study found that breeding pairs of birds had similar beak sizes. Male and females with small beaks tended to breed together, and males and females with large beaks tended to breed together. Mate selection maintained the biomodal distribution in the population during extremely wet conditions. If beak size wasn't a factor in mate selection, the beak size would even out.

Pairing under dry conditions

2. How does beak size relate to fitness (differential reproductive success) in G. fortis?

Female beak size (single measure)S.K.Huber

l.aet 2007 -2.0 3.0 -2.0-1.001.02.03.04.0 -1.0 0 measure)(singlesizebeakMale 1.0 2.0

Beak sizes of G. fortis were measured over a three year period (2004-2006), at the start and end of each year. At the start of the year, individuals were captured, banded, and their beaks were measured.

Female beak size (single measure)S.K.Huber l.aet 2007 -2.0 3.0 -1.0-2.001.02.03.04.0 -1.0 0 1.0 2.0 measure)(singlesizebeakMale

Higher fitness

Fitness is a measure of the reproductive success of each genotype.

(b) Give reasons for your answer:

1. (a) How did the drought affect seed size on Santa Cruz Island?

Disruptive Selection in Darwin's Finches

The proportion of banded individuals in the population at the end of the year gave a measure of fitness. Absent individuals were presumed dead (fitness = 0).

Measurements of the beak length, width, and depth were combined into one single measure -2.0 (2004-2006)fitnessLocal

Large beak G. fortis

The Galápagos Islands, 970 km west of Ecuador, are home to the finch species Geospiza fortis. A study during a prolonged

Fitness showed a bimodal distribution (arrowed) being highest for smaller and larger beak sizes.

Beak size pairing in Geospiza fortis

l.aet 2007 -2.0 3.0 -2.0-1.001.02.03.04.0 -1.0 0 measure)(singlesizebeakMale 1.0 2.0

Pairing under extremely wet conditions

Female beak size (single measure)S.K.Huber

Key Idea: Disruptive selection in the finch Geospiza fortis produces a bimodal distribution for beak size.

(b) How did the change in seed size during the drought create a selection pressure for changes in beak size?

The presence or absence of banded individuals was recorded at the end of the year when the birds were recaptured. Recaptured individuals had their beaks measured.

1.00.80.60.40.20

Beak size vs fitness in Geospiza fortis

Fitness related to beak size showed a bimodal distribution (left) typical of disruptive selection.

Pairing under extremely wet conditions

88 WEB 88 LINK 84 LINK 87

HendryA.P. alet. 2009 -1.5 -1.0 -0.5 0 Beak size (single measure)0.51.0 1.5 2.0 2.5

3. (a) Is mate selection in G. fortis random / non-random? (delete one)

Small beak G. fortis

Female beak size (single measure)S.K.Huber l.aet 20073.0-1.0 0 1.0 2.0

Pairing under dry conditions

Women also have a high requirement for calcium during pregnancy and lactation. Populations that live in the tropics receive enough ultraviolet (UV) radiation to synthesise vitamin D all year long. Those that live in northern or southern latitudes do not. In temperate zones, people lack sufficient UV light to make vitamin D for one month of the year. Those nearer the poles lack enough UV light for vitamin D synthesis most of the year (above). Their lighter skins reflect their need to maximise UV absorption (the photos show skin colour in people from different latitudes).

IraqFrance The NetherlandsAlaska Japan

colour in humans: a product of natural selection 80°40°0°40°80°40°0°40° No

most of year

from Jablonski & Chaplin, Sci. Am. Oct. 2002

Adapted

WEB 89

Selection for Skin Colour in Humans

Insufficient UV one

Human skin colour is the result of two opposing selection pressures. Skin pigmentation has evolved to protect against destruction of folate from ultraviolet light, but the skin must also be light enough to receive the light required to synthesise vitamin D. Vitamin D synthesis is a process that begins in the skin and is inhibited by dark pigment. Folate is needed for healthy neural development in humans and a deficiency is associated with fatal neural tube defects. Vitamin D is required for the absorption of calcium from the diet and therefore normal skeletal development.

ISBN: 978-1-927309-56-8

month

GreyLisaPhoto:

Burundi

Skin Insufficientdata

MalaysiaPeru Liberia Botswana SouthernChinaIndia

120

Insufficient UV one

Insufficient UV most of year

Sufficient UV all year

Photocopying Prohibited

Sufficient UV all year

Key Idea: Skin colour is the result of a dynamic balance between two different selection pressures linked to fitness. Pigmented skin of varying tones is a feature of humans that evolved after early humans lost the majority of their body hair. However, the distribution of skin colour globally is not random; people native to equatorial regions have darker skin tones than people from higher latitudes. For many years, biologists postulated that this was because darker skins had evolved to protect against skin cancer. The problem with this explanation

was that skin cancer is not tied to evolutionary fitness because it affects post-reproductive individuals and cannot therefore provide a mechanism for selection. Physiological and epidemiological evidence has now shown that selection pressures on skin colour are finely balanced to produce a skin tone that regulates the effects of the sun's UV radiation on the nutrients vitamin D and folate, both of which are crucial to successful reproduction and therefore evolutionary fitness. The selection is stabilising within each latitudinal region.

1. (a) Describe the role of folate in human physiology:

(b) Describe the role of vitamin D in human physiology:

2. (a) Early hypotheses to explain skin colour linked pigmentation level only to the degree of protection it gave from UV-induced skin cancer. Explain why this hypothesis was inadequate in accounting for how skin colour evolved:

(b) Explain how the new hypothesis for the evolution of skin colour overcomes these deficiencies:

4. The Inuit people of Alaska and northern Canada have a diet rich in vitamin D and their skin colour is darker than predicted on the basis of UV intensity at their latitude. Explain this observation:

3. Explain why, in any given geographical region, women tend to have lighter skins (by 3-4% on average) than men:

5. (a) What health problems might be expected for people of African origin (right) now living in northern UK?

(b) How could these people avoid these problems in their new higher latitude environment?

Variation, selection, and fitness

HINT: What effect does mutation have on variation? Provide examples of mutations.

HINT: What is variation and how does it arise? What is fitness and what is its significance?

HINT: Describe how natural selection acts upon phenotypic variation. Describe the three types of natural selection.

What You Know So Far: Processes in Gene Pools

REVISE 122

Natural selection

Mutations

Photocopying Prohibited

1. HIV/AIDS has killed more than 25 million people globally and infected another 33 million since it was first recognised in 1981. In the mid 1990s, it was found that the HIV-1 virus entered T-cells of the immune system by docking with the receptor protein encoded by the CCR5 gene. Soon after this, it was discovered that the deletion of 32 bases in the gene (mutation CCR5D32) produces a premature stop codon in the mRNA, resulting in a non-functional receptor protein and resistance to HIV-1.

Style Question: Mutation and Evolution

Western Europe has also been the site of many smallpox epidemics before its elimination in 1980. Hypotheses for the prevalence of the CCR5D32 mutation vary. A possible hypothesis is that CCR5D32 may have conveyed some immunity to smallpox or plague or both.

(a) Discuss the nature of the CCR5D32 mutation, including the significance of the premature stop codon to HIV resistance:

Geographical studies have found that the CCR5D32 mutation is found in light-skinned people of European descent in some areas of northern Europe where it is carried by up to 18% of the population. The mutation is virtually absent in Asian, Middle Eastern, and American Indian populations.

181410161284026CCR5withpopulation% Δ mutation32

(b) Discuss the spread of the CCR5D32 mutation through the European population. Include past and future selection pressures. You may use more paper if required.

A The observable characteristics in an organism.

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B A heritable characteristic of a species that equips it for survival and reproductive success in its environment.

KEY TERMS AND IDEAS: Processes in Gene

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D The process by which favourable heritable traits become more common in successive generations.

H A change in the base sequence of DNA; the ultimate source of new alleles.

I A change in the allele frequency of a population over time.

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F Random changes in allele frequency between generations as a result of the different contributions of individuals to the alleles in the gene pool of the next generation.

adaptation (noun)

3. Compare and contrast the role of genetic drift and natural selection in changing the genetic makeup of a population:

G A measure of an individual's relative genetic contribution to the next generation as a result of its combination of traits.

4 (a) Describe the features of stabilising selection: (b) Using an example, explain what might cause selection to shift from stabilising to directional:

E The collective group of genes in a population.

1.variationphenotypenaturalmutationgeneticgenefitnessevolutionpooldriftselectionTestyourvocabulary by matching each term to its definition, as identified by its preceding letter code.

2. Fill in the missing gaps using the word list provided: environmental conditions, adaptive advantage, DNA, harmful, silent, alleles, eliminated. Mutations are changes in an organism's and they are the source of new in a population. Most mutations are and so are from the population. Inherited beneficial mutations provide an so are retained in the population. Mutations that do not change the amino acid sequence are called mutations. They are retained in the population but may not be subjected to selection pressures unless the change.

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C The differences between individuals in a population as a result of genes and environment.

Domestic dog Canis familiaris

Dingo Canis familiaris dingo

Key Idea: A biological species is a group of organisms that can successfully interbreed to produce fertile offspring. A biological species is defined as a group of individuals capable of interbreeding to produce fertile offspring and reproductively isolated from other such groups. Although simple by definition, species are more difficult to define

Side-striped

Coyote – red wolf hybrids InterbreedingNo

Black-backed jackal Canis mesomelas Golden jackal Canis aureus

Coyote Canis latrans

The Biological Species Concept

The ability of many Canis species to interbreed to produce fertile hybrids illustrates one of the problems with the traditional concept of the biological. Red wolves, grey wolves, Mexican wolves, and coyotes can all form fertile hybrids. Red wolves are very rare, and it is possible that hybridisation with coyotes has been a factor in their decline. By contrast, no interbreeding occurs between the three distinct species of jackal, even though their ranges overlap in the Serengeti of eastern Africa. These animals are highly territorial, and simply ignore members of the other jackal species.

Grey wolf Canis lupus

InterbreedingNo

Distribution of Canis species

WEB 93 1. (a) Define the term biological species: (b) In what way do the Canis species contradict the definition of a biological species? 2. What type of barrier prevents the three species of jackal from interbreeding? 3. Describe the factor that has prevented the dingo from interbreeding with other Canis species (apart from the dog): 4. Describe a possible contributing factor to the occurrence of interbreeding between the coyote and red wolf:

Side-striped jackal Canis adjustus

Red [formerwolfrange]Coyote[rangeexpansion]

Grey wolf Grey wolf Grey wolf Dingo Mexican wolf [former range]

Mexican wolf Canis lupus baileyi

in reality. For example, some closely related species will interbreed to produce fertile hybrids, e.g. Canis species. The concept of a biological species is also more successfully applied to animals than to plants, which hybridise easily and can reproduce vegetatively. The concept is also problematic for extinct organisms and those that reproduce asexually.

The global distribution of most species of Canis (dogs and wolves) is shown, right. The grey wolf inhabits the forests of North America, northern Europe, and Siberia. The red wolf and Mexican wolf (original distributions shown) were once distributed more widely, but are now extinct in the wild except for reintroductions. In contrast, the coyote has expanded its original range and is now found throughout North and Central America. The range of the three jackal species overlap in the open savannah of eastern Africa. The dingo is distributed throughout Australia.

Golden Black-backedjackal jackal jackal

Distribution of the domestic dog is global as a result of their association with humans. The dog has been able to interbreed with all other members of the genus listed here to form fertile hybrids. Contrast this with members of the horse family, in which hybrids are sterile.

Red wolf Canis rufus

Interbreeding between Canis species

The circumpolar distribution of Larus subspecies (still often cited in many texts) inspired Mayr to propose the ring species hypothesis. However, mtDNA studies (Liebers et al. 2004) have indicated that there were two ancestral gull populations (not one) and most of Mayr's subspecies in fact deserve species status. Moreover, the Larus complex includes several species, excluded by Mayr, whose taxonomy is unclear. Ring species appear to be a very rare phenomenon if they exist at all. In contrast, cryptic (hidden) species, which are morphologically identical but behave as (reproductively isolated) true species, appear to be common.

in action. However, such examples are rare, and rigorous analysis of supposed ring species, including the herring gull complex, have shown that they do not meet all the necessary criteria to be ring species as defined. Although ring species are rare, the concept is still helpful because it can allow us to reconstruct the divergence of populations from an ancestral species. Ring species also provide evidence that speciation may occur without complete geographical isolation.

Key Idea: A ring species is a connected series of closely related populations, distributed around a geographical barrier, in which adjacent populations in the ring can interbreed, but those at the extremes of the ring are reproductively isolated.

The variation in populations may occur in a geographical ring, e.g. around a continental shoreline (B). Adjacent populations in the cline can interbreed. If the ring closes (C), the populations at the extremes of the ring may meet but are too different to interbreed.

f The terminal populations are reproductively isolated.

Photo right: Greenish warbler populations occupy a ring around the Tibetan Plateau. Eastern and western populations meet in Siberia but do not interbreed. Analyses support their status as a ring species.

94 LINK 95 WEB 94 1. What is a ring species? 2. Why is the phenomenon of ring species interesting to evolutionary biologists? 3. Explain why the populations the two extremes of a geographical ring, as depicted in the diagram, cannot interbreed:

f They show expansion of their range around a geographic barrier, such a mountain range or desert.

The ring species concept was proposed by Ernst Mayr in 1942 to account for the circumpolar distribution of species of herring gulls (Larus species). The idea of a ring species is attractive to biologists because it appears to show speciation

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Ring

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Criteria for a ring species

What is a ring species?

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f Adjacent populations in the ring can interbreed to produce fertile offspring (gene flow).

1 2 3 4 5 1 2 3 4 5 A: Natural populations along a cline (environmental gradient). Each population varies slightly from the next. 1 2 3 4 5 B C

Photo left: The herring gull (front) and black-backed gull (rear) do not interbreed at the ends of the circumpolar ring where they coexist. However, genetic analyses do not support a ring species.

What are Species?

f Ring species develop from a single ancestral population with isolation by distance.

ISBN: 978-1-927309-56-8

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3. Explain why the greenish warbler is described as "evolution in action":

Song spectra of the greenish warbler

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Greenish warblers (Phylloscopus trochiloides) are found in forests across much of northern and central Asia. They inhabit the ring of mountains surrounding the large area of

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ECD

1. How do the eastern and western Siberian populations of greenish warblers differ?

Ring Species: The Greenish Warbler

desert which includes the Tibetan Plateau, and Taklamakan and Gobi deserts, and extends into Siberia. In Siberia, two distinct subspecies coexist and do not interbreed, but are apparently connected by gene flow around the Himalayas to the south. The greenish warblers may thus form a rare example of a ring species.

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A B

Key Idea: Genetic and song analyses provide strong evidence that greenish warblers form a ring species that originated south of the Himalayas.

2. Explain how these differences might have occurred:

F G H

A B C D E

East and west populations eventually rejoined in Siberia, but because of morphological, behavioural, and genetic differences they do not interbreed.

No gene flow

F G H

Genetic data and analysis of song spectra point to a single species establishing on the southern edge of the Himalayas about 10,000 years ago.

The greenish warbler has been touted as "Darwin's missing evidence", showing how one species can diverge and evolve into two when populations are separated and subjected to different selection pressures.Gene flow

The two coexisting subspecies of greenish warblers are distinguished by their songs and the number of bars on the wings. The warbler in western Siberia has one light bar across the top of the wing, while the warbler in eastern Siberia has two. Analysis of the songs around the ring show that all songs can be traced to the population labelled A above. Songs become progressively different moving east or west around the ring. The songs of the eastern warblers (H) and western warblers (E) in Siberia are so different that neither recognises the other. Eastern and western forms have subspecies status

Populations spread both east and west along the Himalayas. Populations developed unique characteristics, but adjacent populations remained able to breed together.

Lorax

Key Idea : Reproductive isolating mechanisms prevent interbreeding between different species. Prezygotic isolating mechanisms occur before fertilisation can take place. Reproductive isolation prevents successful interbreeding between species and is crucial to maintaining species' integrity. Prezygotic isolating mechanisms operate before fertilisation can occur and prevent "gamete wastage". They are the most common type of isolating mechanism and may

VictoriaLake TanganyikaLake MalawiLake ObservatoryEarthNASAPhotos:DOC-CV

Example: Hochstetter’s and Archey’s frogs (right) are sympatric (occur in the same geographical area) in the Coromandel region, but occupy different habitats within that range. Archey’s frog has no webbing between the toes and is found in forested areas away from water where it climbs into damp vegetation. Hochstetter's frog has partial toe webbing and prefers stream margins.

Ecological (habitat) isolation

Archey’s frog

cc2.5GreenM.David LINK 93 LINK 97 WEB 96

be associated with behaviour, morphology, or reproductive timing. Single barriers to gene flow (such as geographical barriers) are usually insufficient to isolate a gene pool, so most species commonly have more than one type of barrier. Geographical barriers are not strictly a reproductive isolating mechanism, because they are not part of the species’ biology, although they are usually a necessary precursor to reproductive isolation in sexually reproducing populations.

Example: Geological changes to the lake basins has been instrumental in the proliferation of cichlid fish species in the rift lakes of East Africa (far right). Similarly, many Galápagos Island species (e.g. iguanas, finches) are now quite distinct from the Central and South American mainland species from which they separated.

Ecological isolation describes the existence of a prezygotic reproductive barrier between two species (or sub-species) as a result of them occupying or breeding in different habitats within the same general geographical area. Ecological isolation includes small scale differences (e.g. ground or tree dwelling) and broad differences (e.g. desert vs grasslands). Ecological isolation often follows geographical isolation, but in many cases the geographical barriers may remain in part.

Prezygotic Reproductive Isolating Mechanisms

Temporal isolation means isolated in time, and it prevents species interbreeding because they mate or they are active at different times. For example individuals from different species do not mate because they are active during different times of the day (e.g. one species is active during the day and the other at night) or in different seasons.

Example: Closely related animal species may have different breeding seasons or periods of emergence to prevent interbreeding. The periodical cicadas (Magicicada genus) are an excellent example of this. Periodical cicadas are found in North America. There are several species and some have an overlapping distribution. Most of their life is spent underground as juveniles, emerging to complete their development and to mate. To prevent interbreeding, the various species spend either 13 or 17 years underground developing. Emergence of a single species is synchronised so the entire population emerges at the same time to breed.

Periodical cicada

Periodical cicada emerging

Geographical isolation

Geographical isolation describes the isolation of a species population (gene pool) by some kind of physical barrier, for example, mountain range, water body, isthmus, desert, or ice sheet. Geographical isolation is a frequent first step in the subsequent reproductive isolation of a species.

Hochstetter’s frog

MarlinBruce

Temporal isolation

Red sea urchin

Example: Two species of sea urchin, the red sea urchin (Strongylocentrotus franciscanus) and the purple sea urchin (Strongylocentrotus purpuratus), share the same geographic range. Sea urchins release their gametes into the sea water, but the two species do not interbreed because their gametes are not compatible.

Many flowering plants have coevolved with their animal pollinators and have flower structures to allow only that insect access. Structural differences in the flowers and pollen of different plant species prevents cross breeding because pollen transfer is restricted to specific pollinators and the pollen itself must be species compatible.

Gamete Isolation

Mechanical (morphological) isolation

cc3.0OnthankL.KirtTaollan82;

Structural differences (incompatibility) in the anatomy of reproductive organs prevents sperm transfer between individuals of different species. This is an important isolating mechanism preventing breeding between closely related species of arthropods.

Example: The sexual organs of empid flies have a lock-and-key mechanism. Without the right shaped genitalia, individuals cannot mate.

Example: Galápagos frigatebirds have an elaborate display in which they inflate a bright red throat pouch to attract a mate.

Behavioural Isolation

Birds exhibit a wide range of courtship displays. The use of song is widespread but ritualised movements, including nest building, are also common.

Frog calling

Purple sea urchin

cc3.0OnthankL.Kirt

In many species, courtship behaviours are a necessary prelude to successful mating. These behaviours may include dances, calls, displays, or the presentation of gifts. The displays are very specific and are unique to each species. This means that mates of the same species recognise and are attracted to the individual performing the behaviour, but members of other species do not recognise or pay attention to the behaviours.

Male frigatebird display

Empid flies

Orchidmating+ + Species A Species B

The gametes (eggs and sperm) from different species are often incompatible, so even if the gametes meet, fertilisation is unsuccessful. Gamete isolation is very important in aquatic environments where the gametes are released into the water and fertlisation occurs externally (e.g. reproduction in frogs, fish, and coral). Where fertilisation is internal, the sperm may not survive in the reproductive tract of another species. If the sperm does survive and reach the egg, chemical differences in the gametes prevent fertilisation. Chemical recognition is also used by flowering plants to recognise pollen from the same species. Pollen from a different species is recognised as foreign and it does not germinate.

(c) Two species of New Zealand skinks, Oligosoma smithi and O. suteri are sympatric (same area) in north-eastern New Zealand. O. smithi is diurnal and gives birth to live young. O. suteri is nocturnal and lays eggs.

2. What is a prezygotic isolating mechanism?

(b) What role do isolating mechanisms have in maintaining the integrity of a species?

(b) Male bowerbirds construct elaborate bowers (shelters) to attract a mate. One species, the MacGregor's bowerbird builds a tall structure and decorates it with charcoal. A second species, the satin bowerbird, decorates its bower with bright blue objects:

Breeding season for species A Breeding season for species B

White sage

1. (a) What is a reproductive isolating mechanism?

Black sage

(b) Explain why, despite this, it often precedes, and is associated with, reproductive isolation:

(a) Two species of butterfly (right) coexist in the same habitat but have different breeding seasons:

J F M A M J J A S O N D

4 Distinguish between geographical and ecological isolation:

(e) Two species of sage plants coexist in a region of Southern California. Black sage (Salvia mellifera) has small flowers and is pollinated by small bees while white sage (S. apiana) has larger flowers providing a larger landing platform for its larger pollinator, carpenter bees. The two species of sage remain reproductively isolated.

3. (a) Why is geographical isolation not regarded as a reproductive isolating mechanism?

5. Identify the type(s) of reproductive isolation described in the following examples:

(d) The blackbird (Turdus merula) and the ring ouzel (Turdus torquatus) are two closely related species found in Europe. The blackbird is a woodland species and the ring ouzel tends to inhabit highlands:

(a) Hybrid inviability:

Hybrid sterility

2. Briefly describe how each of the postzygotic isolating mechanisms maintains reproductive isolation:

Even if two species mate and produce hybrid offspring that are vigorous, the species are still reproductively isolated if the hybrids are sterile (genes cannot flow from one species’ gene pool to the other). Such cases are common among the horse family (such as the zebra and donkey shown on the right). One cause of this sterility is the failure of meiosis to produce normal gametes in the hybrid. This can occur if the chromosomes of the two parents are different in number or structure (see the “zebronkey” karyotype on the right). The mule, a cross between a donkey stallion and a horse mare, is also an example of hybrid vigour (they are robust) as well as hybrid sterility. Female mules sometimes produce viable eggs but males are infertile.

Key Idea: Postzygotic isolating mechanisms operate after fertilisation has occurred.

Hybrid inviability

Hybrid breakdown

integrity of closely related species. There are several different postzygotic mechanisms operating at different stages. The first prevents development of the zygote. Even if the zygote develops into a viable offspring there are further mechanisms to prevent long term viability. These include premature death or (more commonly)

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offspring (2N = 53) Chromosomes contributed by

Postzyotic reproductive isolating mechanisms occur after fertilisation (formation of the zygote) has occurred. Postzygotic isolating mechanisms are less common than prezygotic mechanisms, but are important in maintaining the

(b) Hybrid sterility:

jenny X Chromosomes contributed by zebra stallion Y XstallionZebra (2N = 44) Donkeyjenny (2N = 62) AKA

Mating between individuals of two species may produce a zygote (fertilised egg), but genetic incompatibility may stop development of the zygote. Fertilised eggs often fail to divide because of mis-matched chromosome numbers from each gamete. Very occasionally, the hybrid zygote will complete embryonic development but will not survive for long. For example, although sheep and goats seem similar (right) and can be mated together, they belong to different genera. Any offspring of a sheep-goat pairing is generally stillborn.

Sheep (Ovis) 54 chromosomes Goat (Capra) 60 chromosomes

Postzygotic Isolating Mechanisms

Hybrid breakdown is common feature of some plant hybrids. The first generation (F1) may be fertile, but the second generation (F2) are infertile or inviable. Examples include hybrids between species of cotton (near right), species within the genus Populus, and strains of the cultivated rice Oryza (far right).

‘Zebronkey’ donkey

Karyotypeinfertility.of

1. Postzygotic isolating mechanisms are said to reinforce prezygotic ones. Explain why this is the case:

Sympatric species Drier climate

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Key Idea: Allopatric speciation is the divergence of a species after it is subdivided into geographically isolated populations. Speciation (the formation of new species) most commonly occurs as a result of population separation and subsequent isolation. This is called allopatric speciation because the

There are times when the range of a species expands for a variety of different reasons. A single population in a relatively homogeneous environment will move into new regions of their environment when they are subjected to intense competition (whether it is interspecific or intraspecific). The most severe form of competition is between members of the same species since they are competing for identical resources in the habitat. In the diagram on the right there is a 'parent population' of a single species with a common gene pool with regular 'gene flow' (theoretically any individual has access to all members of the opposite sex for mating purposes).

populationIsolated A

populations diverge after geographical separation (allopatric literally means 'other fatherland' in ancient Greek). It has been important in speciation in New Zealand, which has experienced a number of cycles of geographical fragmentation throughout its history as a result of glacials and interglacials.

Parent population populationIsolated B

Stage 2: Geographical isolation

ISBN: 978-1-927309-56-8

remainsbarrierRiverbarrierdisappears

Stage 3: Different selection pressures

The separated populations (isolated subspecies) undergo genetic and behavioural changes. These ensure that the gene pool of each population remains isolated and 'undiluted' by genes from other populations, even if the two populations should be able to remix (due to the removal of the geographical barrier). Gene flow does not occur. The arrows (diagram, right) indicate the zone of overlap between two species after Species B has moved back into the range inhabited by the parent population. Closely-related species whose distribution overlaps are said to be sympatric species. Those that remain geographically isolated are called allopatric species

Stage 1: Moving into new environments

Parent population

Mountain

Allopatricspecies

Isolation of parts of the population may occur due to the formation of physical barriers, such as mountains, deserts, or stretches of water. These barriers may cut off those parts of the population that are at the extremes of the range and gene flow is prevented or rare. The rise and fall of the sea level has been particularly important in functioning as an isolating mechanism. Climatic change can leave 'islands' of habitat separated by large inhospitable zones that the species cannot traverse. Example: In mountainous regions, alpine species can populate extensive areas of habitat during cool climatic periods. During warmer periods, they may become isolated because their habitat is reduced to ‘islands’ of high ground surrounded by inhospitable lowland habitat.

Stage 4: Reproductive isolation

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Species A

Parent population Species B Subspecies A

Mountain barrier prevents gene flow

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Wetter climate Cooler climate Rivergenepreventsbarrierflow

The isolated populations (A and B) may be subjected to quite different selection pressures. These will favour individuals with traits that suit each particular environment. For example, population A will be subjected to selection pressures that relate to drier conditions. This will favour those individuals with phenotypes (and therefore genotypes) that are better suited to dry conditions. They may for instance have a better ability to conserve water. This would result in improved health, allowing better disease resistance and greater reproductive performance (i.e. more of their offspring survive). Finally, as allele frequencies for certain genes change, the population takes on the status of a subspecies. Reproductive isolation is not yet established but the subspecies are significantly different genetically from other related populations.

Parent population Subspecies B

5. Explain how cycles of climate change can cause large changes in sea level (up to 200 m):

(b) How might emigration achieve the same effect as geographical isolation?

8. Explain how reproductive isolation could develop in geographically separated populations:

6. (a) What kinds of physical barriers could isolate different parts of the same population?

3. Plants are unable to move. How might plants disperse to new environments?

1. Distinguish between allopatric and sympatric species:

7 (a) How might selection pressures differ for a population that becomes isolated from the parent population?

2. Why do some animals, given the opportunity, might move into new environments?

(b) Describe the general effect of the change in selection pressures on the allele frequencies of the isolated gene pool:

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4. Describe the amount of gene flow within a parent population prior to and during the expansion of a species' range:

Oahu

2. Explain why these flies are of interest:

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(commonly known as fruit flies) are a group of small flies found almost everywhere in the world. Two genera, Drosophila and Scaptomyza are found in the Hawaiian islands and between them there are more than 800 species present on a land area of just 16,500 km2; it is one of the densest concentrations of related species found anywhere. The flies range from 1.5 mm to 20 mm in length and display a startling range of wing forms and patterns, body shapes and colours, and head and leg shapes. This diverse array of species and characteristics has made these flies the subject of much evolutionary and genetics research. Genetic analyses show that they are all related to a single species that may have arrived on the islands around 8 million years ago and diversified to exploit a range of unoccupied niches. Older species appear on the older islands and more recent species appear as one moves from the oldest to the newest islands. Such evidence points to numerous colonisation events as new islands emerged from the sea. The volcanic nature of the islands means that newly isolated environments are a frequent occurrence. For example, forested areas may become divided by lava flows, so that flies in one region diverge rapidly from flies in another just tens of metres away. One such species is D. silvestris. Males have a series of hairs on their forelegs, which they brush against females during courtship. Males in the northeastern part of the island have many more of these hairs than the males on the southwestern side of the island. While still the same species, the two demes are already displaying structural and behavioural isolation. Behavioural isolation is clearly an important phenomenon in drosophilid speciation. A second species, D. heteroneura, is closely related to D. silvestris and the two species live sympatrically. Although hybrid offspring are fully viable, hybridisation rarely occurs because male courtship displays are very different.

The major dispersals

New Zealand alpine buttercups (Ranunculus) are some of the largest in the world and are also the product of repeated speciation events. There are 14 species of Ranunculus in New Zealand; more than in the whole of North and South America combined. They occupy five distinct habitats ranging from snowfields and scree slopes to bogs. Genetic studies have shown that this diversity is the result of numerous isolation events following the growth and recession of glaciers. As the glaciers retreat, alpine habitat becomes restricted and populations are isolated at the tops of mountains. This restricts gene flow and provides the environment for species divergence. When the glaciers expand again, the extent of the alpine habitat increases, allowing isolated populations to come in contact and closely related species to hybridise.

3. Describe the relationship between the age of the islands and the age of the fly species:

1. Explain why so many drosophilidae are present in Hawaii:

VelelaPhoto:

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Giant

Kauai

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Small Flies and Buttercups

4. Explain why New Zealand has so many alpine buttercups:Drosophilidae

Drosophila setosimentum, a picture winged fly.

HawaiiMaui

1. Identify

Over time, only boulder-sitting butterflies are found in the highlands and grass-sitting butterflies in the lowlands. Occasionally wind brings members of the two groups together, but if they mate, the offspring are usually not viable or have a much lowered fitness.

Key Idea: Speciation may occur in stages marked by increasing isolation of diverging gene pools. Physical separation is followed by increasing reproductive isolation. The diagram below shows a possible sequence of events in the origin of two new species from an ancestral population. Over time, the genetic differences between two populations

populationAncestral timeordevelopmentEvolutionary Separate species Gene flow uncommon Population splits PopulationA PopulationB Species A Species B Race A Race B SubspeciesA SubspeciesB Gene flow common

In the highlands, boulder-sitting butterflies (BSBs) do better than grass-sitting butterflies (GSBs). In the lowlands, the opposite is true. BSBs only mate on boulders with other BSBs. Darker BSBs have greater fitness than light BSBs. (they can absorb more heat from the boulders). In the lowlands, light GSBs blend in with the grass and survive better than darker butterflies.

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2. What were the selection acting on BSBs the highlands and GSBs the lowlands respectively?

increase and the populations become increasingly isolated from each other. The isolation of the two gene pools may begin with a geographical barrier. This may be followed by progressively greater reduction in gene flow between the populations until the two gene pools are isolated and they each attain species status.

Divergence in Allopatric Populations

pressures

Continued mountain building raises the altitude of the plateau, separating two populations of butterflies, one in the highlands the other in the lowlands.

the variation in behaviour in the original butterfly population:

Eventually gene flow between separated populations ceases as variation between the populations increases. They fail to recognise each other as members of the same species.

A species of butterfly lives on a plateau. The plateau is covered with grassland strewn with boulders. During colder weather, some butterflies sit on the sun-heated boulders to absorb the heat, while others retreat to the lower altitude grassland to avoid the cold.

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Tetraploid

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common in plants, and has been important in the evolution and speciation of flowering plants (angiosperms). Polyploidy in plants produces a species that is reproductively isolated from the “parent” species, and results in instant speciation. Allopolyploidy (involving different species) and autopolyploidy (involving the same species) are both recognised.

Potatoes (left) are autopolyploids. They have a number of ploidy levels, based on a haploid number of 12, ranging from diploid (2n=24) to hexaploid (6n=72). Cultivated potato varieties are tetraploid (4n=48). crops are allopolyploids, including wheat, rice, and modern brassicas (above).

Many

Key Idea: Polyploidy is a condition in which a cell or organism has three or more times the haploid chromosome number. Polyploidy cells or organisms contain more than two haploid number of chromosomes (i.e. 3N or more). It arises when chromosomes fail to correctly separate during mitosis or meiosis (non-disjunction). Polyploidy is rare in animals, but

Polyploids that arise within a species are called autopolyploids (the extra chromosomes come from another organism of the same species). Autopolyploidy occurs when chromosomes fail to separate during meiosis or when the cell fails to divide after the chromatids have separated. If a diploid gamete fuses with a haploid gamete, a triploid is formed. Triploids are generally unstable and sterile. However, if two diploid gametes fuse, the resulting tetraploid can be fertile. 3N 4N

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AAAA AA Same species AA AAA A Same species AA AA AA AA AA gametehaploidNormal gameteDiploid gametesDiploid hybridSterile hybridFertile Triploid

Autopolyploidy

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Allopolyploidy

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ABAB Species A Species B Species C A AB AABB AABB B AA BB Haploid gametes hybridInfertile Infertile plants:specieshybridUnionintheNon-disjunctionreproduceshybridasexually.doubleschromosomenumberthehybrid.ofgametesfromthisproducesanewofinterbreedinga fertile allopolyploid.

Polyploidy a Source of Variation

Allopolyploidy occurs when two species interbreed to produce a new hybrid with chromosomes from each of the parent species. The hybrid is infertile because the chromosomes cannot pair up. However, mitotic non-disjunction in the sterile hybrid can double the chromosome number and produce homologues, which can pair up during meiosis. Self-fertilisation may then produce a viable, fertile hybrid. Many commercial plant varieties are allopolyploids. They show greater heterozygosity and hybrid vigour than autopolyploids.

f New plant varieties can be made by inducing non-disjunction with chemicals. The induction of polyploidy is a common technique to overcome hybrid sterility during plant breeding.

f Non-disjunction is induced in a diploid to produce a tetraploid, which is crossed with a normal diploid to produce the seedless triploid hybrid. Colchicine

2. (a) What advantages do polyploid organisms often have over the parent species?

Polyploids can be induced

f Polyploidy results in gene redundancy and provides opportunities to diversify gene function. Extra copies of the gene not required for its original function can be adapted for use in a different way. This can provide an evolutionary advantage. Many polyploids show novel variation or morphologies relative to their parental species. wheat 6N = 42

Common

f Seedless banana and watermelon fruits are produced on triploid plants, which cannot produce fertile gametes (therefore no seeds).

3. Distinguish between autopolyploidy and allopolyploidy:

f Chemicals such as colchicine (right) and N2O gas inhibit spindle fibre formation and stop the separation of chromosomes during mitosis.

f In plants, seeds or seedlings are soaked in a solution of a spindle inhibiting chemical. The resulting plants will likely develop as polyploids. These can then be propagated and crossed (if fertile) to produce a new variety of plant.

(b) Explain the origin of these advantages:

6NKiwifruit=174

Tobacco4N=48 3NBanana=27 Boysenberry7N=49 Strawberry8N=56

4. (a) How does non-disjunction result in polyploidy?

(b) Using an example, explain how deliberate induction of non-disjunction can be used in producing crop varieties:

Advantages of polyploidy

1. Explain how polyploidy can result in instant genetic isolation?

f The high frequency of polyploidy in plants indicates that polyploidy provides an adaptive advantage. Often this advantage is the result of hybrid vigour, where the hybrid shows improvements over the parents (e.g. by being larger or growing more vigorously). The increase in heterozygosity (heterozygous for a gene) reduces the frequency of (expressed) recessive mutations and also contributes to hybrid vigour.

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New polyploid plant species spreads outwards through the existing parent population populationParent

Original host plant species New host plant species

1. Explain what is meant by sympatric speciation:

Polyploidy may result in the formation of a new species without isolation from the parent species. This event, occurring during meiosis, produces sudden reproductive isolation for the new group. Because the sex-determining mechanism is disturbed, animals are rarely able to achieve new species status this way (they are sterile). Many plants, on the other hand, are able to reproduce vegetatively, or carry out self pollination. This ability to reproduce on their own enables such polyploid plants to produce a breeding population.

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Origin of polyploid event

Geneflow geneNoflow

geographic region. Sympatric speciation is rarer than allopatric speciation, although it is not uncommon in plants which form polyploids. There are two situations where sympatric speciation is thought to occur. These are described below.

An insect forced to lay its eggs on an unfamiliar plant species may give rise to a new population of flies isolated from the original population.

Original host plant species New host plant species

Geneflow geneNoflow

Key Idea: Sympatric speciation is speciation which occurs even when there is no physical barrier separating gene pools. In sympatric (same place) speciation, a new species evolves from a single ancestral species while inhabiting the same

2. What is the mechanism for instant speciation? Explain why it is more common in plants than in animals:

In a heterogeneous environment (one that is not the same everywhere), there are many microhabitats within the region inhabited by a population. Some organisms prefer to occupy one particular microhabitat most of the time, only rarely coming in contact with those that prefer other microhabitats. Some organisms become so dependent on the resources offered by their particular microhabitat that they never interact with their counterparts in different microhabitats.

Speciation by allopolyploidy

Example: Some host-specific phytophagous insects (insects that feed on plants) prefer to lay eggs on plants identical to the species they themselves hatched on. Host plant preference leads to isolation within the same geographical area.

Niche isolation

3. Explain how niche differentiation could result in the formation of a new species:

Origin of polyploid event

Reproductive isolation

This type of polyploidy usually arises from the doubling of chromosomes in a hybrid between two different species. The doubling often makes the hybrid fertile.

Examples: Modern wheat. Swedes are polyploid species formed from a hybrid between a type of cabbage and a type of turnip.

Instant speciation by polyploidy

Sympatric Speciation

Speciation through niche differentiation

Individual groups, which have remained genetically isolated because of their microhabitat preferences, become reproductively isolated. They have become new species with subtle differences in behaviour, structure, and physiology. Gene flow (via sexual reproduction) is limited to organisms that share similar microhabitat preferences (as shown right).

New host plant species

New polyploid plant species spreads outwards through the existing parent population populationParent

New host plant species

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Original host plant species

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f M. drucei is unusual in that it is a stable triploid and produces viable offspring, so it is called a permanent odd triploid. M. drucei is most similar in appearance to M. flexuosus, but in height and flower type it resembles the M. alpinus group. M. drucei, is a triploid (2N=48)

f M. drucei (right) probably arose through a hybridisation event between M. flexuosus and M. alpinus M. drucei, is found only in the Ahukawakawa Swamp and Pouakai Range within Egmont National Park (Taranaki). It is restricted by the Pouakai volcano, and the extent of its habitat is 2 ha.

range of habitats ranging from coastal regions to alpine areas. Polyploidy has played an important role of speciation in Melicytus, including in the most recently named M. drucei, a hybrid found only on Mt. Taranaki. M. drucei is unusual in that it is a stable triploid (3N). The other Melicytus species are diploids (2N) or tetraploids (4N).

Polyploidy and Speciation in Melicytus

f Both parent species occur in the Central North Island but not within Egmont National park. The hybridisation event would have occurred when the parent species had more widespread distributions. The limited distribution of M. drucei suggests its formation was a single hybridisation event.

M. alpinus growth form

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ClarksonWM 1. Has M. drucei arisen through autopolyploidy or allopolyploidy? 2. Using M. drucei as an example, discuss the role of polyploidy in speciation of Melicytus: 3. What evidence is there to suggest that M. drucei arose from a single hybridisation event? With thanks to Bruce Clarkson, Jeremy Wolfe, Melissa Hutchinson, John Barkla, and Rewi Elliot and the NZ Plant Conservation Network for photographs.

BarklaJohn

M. flexuosus (left) can grow up to 5 m tall. It is restricted to a few regions south of Pureora in the North Island but widespread throughout the South Island. It has divaricating, near leafless branches with many lenticels (pores) for gas exchange through the stems. It produces small flowers, which sit under the branches. M. flexuosus is diploid (2N=32).

M. alpinus (above) is found on coastal and dry alpine areas of the southern North Island and the South Island. It is a dense shrub growing 1-2 m tall. The external branches look like porcupine quills (hence its common name, porcupine shrub). Most of the leaves are found within the canopy, an adaptation to reduce water loss in dry climates. The small weather resistant flowers (top right) are produced in spring and early summer. M. alpinus is a tetraploid (2N = 64)

M. alpinus flowers

Key Idea: Polyploidy has been an important factor in the evolution of the Melicytus species in New Zealand The Melicytus genus of plants found in New Zealand comprise 11 species of shrubs and small trees including mahoe. They are divaricating, meaning they have intertangled branches at wide angles to each other. They are found in a diverse

M. flexuosus

M. drucei foliage

RolfeJeremyHutchinsonMelissa

Species Genome

These two species interbred to form a hybrid and would have initially been sterile.

KNOW

in the domestication of wheat. Polyploidy has also played a major role in the evolution of crop plants. Most higher organisms are diploid, i.e. have two sets of chromosomes (2N), one set derived from each parent. Diploids formed from hybridisation of different species are usually infertile because the two sets of chromosomes cannot pair properly at meiosis. In such hybrids, there are no gametes produced or the gametes are abnormal. In some cases of allopolyploidy, the chromosomes can be doubled and a tetraploid is formed from the diploid. This restores fertility to a hybrid, because each of the original chromosome sets can pair properly with each other during meiosis. These processes are outlined below.

Common wheat

The wild einkorn becomes domesticated in the Middle East. Slight changes in the phenotype occur, but not in the chromosome number.

2NGenomeno.

Triticum aegilopiodes Triticum

Wheat has been cultivated for more than 9000 years and has undergone many changes during the process of its domestication including hybridisation and polyploidy. Hybrids are the offspring of genetically dissimilar parents. They are important because they recombine the genetic characteristics of parental lines and show increased heterozygosity. This is associated with greater adaptability, survival, growth, and fertility in the offspring (called hybrid vigour). There is evidence to show that interspecific hybridisation (hybridisation between different species) was an important evolutionary mechanism

TriticumAegilopsTriticumAegilopsmonococcumspeltoidesdicoccumsquarrosaaestivum

Key Idea: The evolution of wheat involved two natural hybridisation events, accompanied by polyploidy.

Wild einkorn (14 chromosomes, genome AA) evolved into einkorn, which crossed with a wild grass (14 chromosomes, genome BB) and gave rise to emmer wheat (28 chromosomes, genome AABB). Common wheat arose when emmer wheat was crossed with another type of grass (goat grass).

Commonname

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These two species interbred to form a hybrid and would have initially been sterile.

Common wheat is thought to have resulted from two sets of crossings between different species to produce hybrids.

The table on the right and the diagram above show the evolution of the common wheat.

The sterile hybrid undergoes amphiploidy (an allopolyploidy event involving doubling the chromosome number in a hybrid between two species). This creates the fertile emmer wheat.

Sterile hybrid undergoes amphiploidy, doubling the number of chromosomes to create the fertile common wheat.

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ChromosomesN77714721AABBDDDDAABBBBAAAA

ISBN: 978-1-927309-56-8

Polyploidy events in the evolution of wheat

Wild 2NGenomeeinkornno. 2NGenomeEinkornno. Wild 2N2NGenomegrassno.EmmerWheatGenomeno.Goat 2NGenomegrassno.

Wild CommonGoatEmmerWildEinkorneinkorngrasswheatgrasswheat

4. Cultivated wheat arose from wild, weedy ancestors through the selection of certain characters.

6. Why is it important to maintain the biodiversity of wild plants and ancient farm breeds?

(a) Identify the phenotypic traits that are desirable in modern wheat varieties:

Teosinte

3. Discuss the role of polyploidy and interspecific hybridisation in the evolution of wheat:

(b) Suggest how ancient farmers would have carried out a selective breeding programme:

cornModern

1. Using the table on the previous page, label each of the wheats and grasses in the diagram with the correct genome and 2N chromosome number for each plant.

Corn has also evolved during its domestication. Teosinte is thought to be the ancestor to both corn and maize.

Ancient cereal grasses had heads which shattered readily so that the seeds would be scattered widely.

2. Explain the term hybrid vigour:

5. Cultivated American cotton plants have a total of 52 chromosomes (2N = 52). In each cell there are 26 large chromosomes and 26 small chromosomes. Old World cotton plants have 26 chromosomes (2N = 26), all large. Wild American cotton plants have 26 chromosomes, all small. Briefly explain how cultivated American cotton may have originated from Old World cotton and wild American cotton:

Modern wheat has been selected for its non-shattering heads, high yield, and high gluten content.

What You Know So Far: Isolation and Speciation

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HINT: How do you define a species?

REVISE 142

Processes of speciation

HINT: Include definitions for allopatric and sympatric speciation. Explain the role of polyploidy in instant speciation.

Reproductive isolating mechanisms

Species concept

HINT: Explain prezygotic and postzygotic mechanisms

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Sci.

Population G's preferred prey is penguins

Distribution of killer whales in Antarctic waters

F prefers to hunt seals on pack ice

1. Killer whales (Orcinus orca) are found throughout the world's oceans. Researchers have identified that different killer whale populations follow different types of hunting behaviour. In the waters around Antarctica, five populations have been identified (F to J). DNA evidence indicates these populations began to diverge about 250,000 years Populationago.

• the relevant reproductive isolating mechanisms

Style Question: Speciation

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Source: R. Riesch, American,

Population I prefers to hunt Patagonian toothfish

Discuss sympatric speciation using the killer whales as an example. In your discussion include:

Researchers believe that these killer whale populations are showing sympatric speciation.

Population J hunts Antarctic toothfish.

ISBN: 978-1-927309-56-8

Population H hunts minke whales

• an explanation of how sympatric speciation differs from allopatric speciation.

• how sympatric speciation occurs

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• a justification as to whether or not sympatric speciation is indeed occurring in killer whales.

F H GJ I

Nov. 2016, pp. 54-61

G A reproductive isolating mechanism that occurs before formation of the zygote.

Subspecies B Species B (a) (b) (c)

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Population B Race B

(c) Two skunk species do not mate despite having habitats that overlap because they mate at different times of the year: Prezygotic / postzygotic (delete one) Mechanism of isolation:

Prezygotic / postzygotic (delete one) Mechanism of isolation:

A A reproductive isolating mechanism that occurs after formation of the zygote

B The division of one species, during evolution, into two or more separate species.

KEY TERMS AND IDEAS: Isolation and Speciation

(a) (b) (c)

populationAncestral

E The condition of having a chromosome complement of more than 2N (e.g. 3N).

(b) Many plants have unique arrangements of their floral parts that stops transfer of pollen between plants:

D Speciation as a result of reproductive isolation without any physical separation of the populations, i.e. populations remain within the same range.

1. Test your vocabulary by matching each term to its definition, as identified by its preceding letter code. allopatric sympatricspeciesspeciationreproductivemechanismprezygoticmechanismpostzygoticpolyploidyspeciationisolatingisolatingisolationspeciation

H Speciation in which the populations are physically separated.

Prezygotic / postzygotic (delete one) Mechanism of isolation:

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Prezygotic / postzygotic (delete one) Mechanism of isolation:

(a) Some different cotton species can produce fertile hybrids, but breakdown of the hybrid occurs in the next generation when the offspring of the hybrid die in their seeds or grow into defective plants:

F Group or population of individuals that can interbreed to produce viable offspring

2. In the following examples, classify the reproductive isolating mechanism as either prezygotic or postzygotic and describe the mechanisms by which the isolation is achieved (e.g. morphological isolation, hybrid sterility etc.):

3. The diagram below shows the divergence of an ancestral population into two new species. In the boxes below, describe the level of gene flow and its effect for each of the labelled points (a-c):

Population A Race A

Subspecies A Species A

C The situation in which members of a group of organisms breed with each other but not with members of other groups

(d) Several species of the frog genus Rana, live in the same regions and habitats, where they may occasionally hybridise. The hybrids generally do not complete development, and those that do are weak and do not survive long:

f Once common throughout New Zealand, the introduction of mammalian predators during European settlement reduced their range and distribution to tiny isolated populations on offshore islands in the north and south. Today, their ranges do not overlap.

mya251299359416444488542

Trilobite diversity Ordovician

Divergent Evolution

Divergent evolution: the lineage splits

Divergent evolution in trilobites

f The saddlebacks are a member of the New Zealand wattlebird family (Callaeidae), which includes the saddleback (tieke), kokako, and the extinct huia.

accumulation of genetic differences in diverging lines, usually following isolation, so that gene flow between them stops and new species arise. Divergence is a common evolutionary pattern. When it involves the diversification of a large number of species into different niches, it is called adaptive radiation.

Changes in genetic makeup accumulate and gene flow stops

DevonianPermianCarboniferousSilurianCambrian *

f There are two very closely related saddleback species: the North Island saddleback (Philesturnus rufusater) and the South Island saddleback (Philesturnus carunculatus).

2. Suggest why the saddlebacks diverged into two separate species:

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Key Idea: Divergent evolution describes the accumulation of differences between initially more similar lineages so that new species arise from a common ancestor. The divergence of two or more species from a common ancestor is called divergent evolution. It arises through the

An overview of divergent evolution

f While they have a similar appearance as adults, the two species show differences in behaviour, breeding, and song. The juvenile birds of each species also differ in appearance.

Divergent evolution in a New Zealand species: The saddlebacks

1. (a) Define divergent evolution: What must generally occur for the new species to arise?

CC3.0WrightDuncan

(b)

Species B Species C

Common ancestor Species A

The North Island saddleback

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Trilobites are extinct marine arthropods. They were one of the earliest arthropod groups and were highly successful, diverging many times during their history to exploit a wide range of niches. They appeared in the fossil record near the beginning of the Cambrian and disappeared in the Permian mass extinction (above).

Time

Mammal: Dolphin

LensIrisLensCornea Cornea Retina Retina

Key Idea: Evolution in response to similar selection pressures can result in unrelated species appearing very similar. Convergent evolution describes the process by which

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Bird: Penguin

Convergence: same look, different origins

The wings of birds and insects are also analogous. The wings have the same function, but the two taxa do not share a common ancestor. Longisquama, a lizard-like creature that lived about 220 mya, also had ‘wings’ that probably allowed gliding between trees. These 'wings’ were highly modified long scales or feathers extending from its back and not a modification of the forearm (as in birds).

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Prohibited 146 Convergent Evolution109

2. Describe two of the selection pressures that have influenced the body form of the swimming animals above: (b)(a)

1. In the example above illustrating convergence in swimming form, describe two ways in which the body form has evolved in response to the particular selection pressures of the aquatic environment: (b)(a)

Fish: Shark

Iris

Analogous structures arise through convergent evolution

species from different evolutionary lineages come to resemble each other because they have similar habitats and ecological roles and natural selection has produced similar adaptations.

Not all similarities between species are the result of common ancestry. Selection pressures to solve similar problems in particular environments may result in similarity of form and function in unrelated (or distantly related) species. The evolution of succulence in unrelated plant groups (Euphorbia and the cactus family) is an example of convergence in plants. In the example (right), the selection pressures of the aquatic environment have produced a similar streamlined body shape in unrelated vertebrates. Icthyosaurs, penguins, and dolphins each evolved from terrestrial species that took up an aquatic lifestyle. Their general body form has evolved to become similar to that of the shark, which has always been aquatic. Note that flipper shape in mammals, birds, and reptiles is a result of convergence, but its origin from the pentadactyl limb is an example of homology (common ancestry).

Analogous structures (homoplasies) have the same function and often the same appearance, but different origins. The example (right) shows the structure of the eye in two unrelated taxa (mammals and cephalopod molluscs). The eye appears similar, but has evolved independently.

Reptile: Icthyosaur (extinct)

Mammalian eye Octopus eye

3. When early taxonomists encountered new species in the Pacific region and the Americas, they were keen to assign them to existing taxonomic families based on their apparent similarity to European species. In recent times, many of the new species have been found to be quite unrelated to the European families they were assigned to. Explain why the traditional approach did not reveal the true evolutionary relationships of the new species:

Selection pressures:

Long-eared bandicoot (f) Adaptations: Jack rabbit

(b) Adaptations:

Marsupial mole (c) Adaptations: Mole

Selection pressures:

Selection pressures: Diet requires chisel-like teeth for gnawing. The need to seek safety from predators on open grassland.

Marsupial mouse (d) Adaptations: Mouse

Selection pressures:

Flying phalanger

Tasmanian wolf (tiger) (e) Adaptations: Wolf

Nor Americath Australia

Convergence between marsupials and placentals

Marsupial and placental mammals diverged very early in mammalian evolution (about 120 mya), probably in what is now the Americas. Marsupials were widespread throughout the supercontinent of Gondwana as it began to break up through the Cretaceous, but became isolated on the southern continents, while the placentals diversified in the Americas and elsewhere, displacing the marsupials in most habitats around the world. Australia's isolation from other landmasses in the Eocene meant that the Australian marsupials escaped competition with placentals and diversified into many species, ecologically equivalent to the placental species in North America.

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Wombat (a) Adaptations: Rodent-like teeth, eat roots and above ground plants, and can excavate burrows. Woodchuck

Flying squirrel

4. For each of the paired examples, briefly describe the adaptations of body shape, diet and locomotion that appear to be similar in both forms, and the likely selection pressures that are acting on these mammals to produce similar body forms:

Selection pressures:

Parasite/host relationships

Trypanosomes are protozoan parasites and are a good example of host-parasite coevolution. Trypanosomes have two hosts, humans and the tsetse fly. The fly vector spreads the parasite between human hosts. Trypanosomes have evolved strategies to evade their host’s defences, but their virulence is constrained by needing to keep their host alive so that they can complete their life cycle. Molecular studies show that Trypanosoma brucei coevolved in Africa with the first hominins around 5 mya, but T. cruzi contact with human hosts occurred in South America only after settlements were made by nomadic cultures.

Crossbill

CDC

tailed bat pollinates wood rose flowers on the forest floor

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Hummingbirds are important pollinators in the tropics. Their needle-like bills and long tongues can take nectar from flowers with deep tubes. Their ability to hover enables them to feed quickly from dangling flowers. As they feed, their heads are dusted with pollen, which is efficiently transferred between flowers.

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Coevolution110 LINK 39 LINK 40 LINK 41 WEB 110

to happen when different species have close ecological interactions with one another. These ecological relationships include predator-prey and parasite-host relationships, and mutualistic relationships such as those between plants and their pollinators. Competition can also drive coevolution because competitors will evolve adaptations, including those involving symbioses, that lead to niche specialisation and more efficient partitioning of available resources.

Pollinator/plant relationships

Predator/prey relationships

Key Idea: Coevolution involves the reciprocal evolution of species that have close ecological relationships, such as those involving mutualism, competition, or exploitation. Coevolution involves the mutual (reciprocal) evolution of two or more species with an ecological relationship. Each party in the coevolution exerts selective pressures on the other and, over time, the species develop a relationship that may involve mutual dependency. Coevolution is likely

Trypanosoma brucei

In most areas of the Rocky Mountains (USA) squirrels are the main predators of lodgepole pine seeds. In areas where there are no squirrels, crossbill birds are the main predator. Lodgepoles have evolved different pinecones depending on which is the main predator. Where squirrels dominate, the pinecones are heavy (harder to carry), have few seeds, and thin scales. Where crossbills dominate the cones are lighter with more seeds and thicker scales (harder to open). Crossbill bill shape varies depending on the region and cone type so that they can extract the seeds.

access.NZ’sshort

Predators have evolved strategies to successfully exploit their prey. Effective offensive weapons (e.g. claws and teeth) and hunting ability (including cooperative hunting tactics) are important. In turn, prey have evolved numerous strategies to protect themselves from predators, including large size and strength, rapid escape tactics, protective coverings, defensive weapons, and toxicity. Lions have evolved the ability to hunt cooperatively to increase their chance of securing a kill from swift herd species such as zebra and antelope.

Bees are excellent pollinators; they are strong enough to enter intricate flowers and have medium length tongues which can collect nectar from many flower types. They have good colour vision, which extends into the UV, but they are red-blind, so bee pollinated flowers are typically blue, purplish, or white and they may have nectar guides that are visible as spots.

Bats are nocturnal and colour-blind but have an excellent sense of smell and are capable of long flights. Flowers that have coevolved with bat pollinators are open at night and have light or drab colours that do not attract other pollinators. Bat pollinated flowers also produce strong fragrances that mimic the smell of bats and have a wide bell shape for easy

Competitive relationships

(b) Why does coevolution occur?

(b) Describe the selection pressures on the monarch butterfly and the milkweed plant in this relationship and explain why it is an example of coevolution:

3. Describe the constraints on the parasite in the coevolution of a host-parasite relationship:

(b) Discuss an evolutionary outcome if tui and bellbird numbers become significantly reduced over time:

2. Describe some of the strategies that have evolved in plants to attract pollinators:

5. The monarch butterfly caterpillar feeds on plants in the milkweed family. The caterpillar has adaptations to survive the toxicity of milkweed, which poisons most other animal species. The milkweed's adaptations to surviving the browse damage caused by the monarch caterpillar include a rapid regrowth response when leaf tissue is damaged.

(a) Why is the relationship between bellbirds and beech mistletoe mutualistic?

(a) What type of ecological relationship is represented here?

UoCLadleyJenny

4. In New Zealand, a mutualistic relationship exists between the beech mistletoe (Peraxilla genus) and its bird pollinators, the tui and bellbird (right). Beech mistletoe have explosive flowers requiring a pollinator to manually open the flower for pollination to occur. The birds twist open the flowers and as the buds spring open, pollen sprays out covering the bird. Pollen is transferred to the next flower the bird visits. Only the tui and bellbirds have access to the nectar inside the flower because not all birds know how to open the flowers. Some native bees have also learned to open the flowers, but they are poor pollinators of mistletoe, with low pollination efficiency.

Bellbird pollinating mistletoe

1. (a) What is meant by coevolution?

diagram below shows the divergence of the mammals into major orders, many occupying niches left vacant by the dinosaurs. The vertical extent of each grey shape shows the time span for which a particular order has existed. Those that reach the top of the chart have survived to the present day. The width of a grey shape shows how many species existed at any given time. The dotted lines indicate possible links between the orders for which there is no direct fossil evidence.

4. Describe one thing that the animal orders labelled D (above) have in common:

Adaptive Radiation in Mammals

2. Name the term that you would use to describe the animal groups at point C (above):

5. Identify the two orders that appear to have been most successful in terms of the number of species produced:

6. Explain what has happened to the mammal orders labelled A in the diagram above:

7. Name the geological time period during which there was the most adaptive radiation:

3. Explain what occurred at point B (above):

10,000 yrs 1.8 my 5 my 25 my 37 my 53 my 65 my 134 my 200 my PleistocenetimeGeologicscaleHolocenePlioceneMioceneOligoceneEocenePaleoceneCretaceousJurassicTriassic Marsupialssloths,Anteatersrabbits,HaresRodentsimatesPrBatsInsectivoresCarnivores&Whales dolphinsOdd-toed ungulatesEven-toed ungulatesElephants MonotremesSea-cows B C A D DA AardvarkHyraxes Colugos PangolinsPinnipoeds shrewsElephant Early mammal Megazostrodon

1. In general terms, describe the adaptive radiation that occurred in mammals:

Key Idea: An ancestral mammal group underwent adaptive radiation about 80 mya and diversified into all the mammalian groups seen today.

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Adaptive radiation is diversification among the descendants of a single ancestral group to occupy different niches. Mammals underwent an extensive adaptive radiation following the extinction of the dinosaurs. Most of the modern mammalian groups became established very early on. The

Beavers are one of the larger types of rodents. They live near rivers, streams and lakes, chewing through small trees to build dams across streams and lodges to live in. Gophers live in burrows, while kangaroo rats are so well adapted to the desert they virtually never need to drink.

Capybaras are South American rodents and the largest of all rodents. They occupy habitats from forests to savannahs. Porcupines are found throughout the Old and New Worlds. Their spines make an almost impenetrable defense against predators. The group also includes guinea pigs, which are popular as pets.

Porcupine-like rodents

Rodent biodiversity

Rats and mice are found in virtually every part of the world thanks to their generalist adaptations and human assisted travel. There are at least 100 species of rats and mice alone. The group also includes voles, lemmings, jerboas and dormice.

Squirrels are found on many continents. Their lifestyles include tree dwelling, ground dwelling, and gliding forms. Like most rodents they are social, with prairie dogs forming large communities called towns.

Beaver-like rodents

Squirrel-like rodents

DormousePorcupine Rat

Guinea pig Kangaroo rat

Beaver ChipmunkSquirrel 1,137+species102+species307+species 290+species 8. Providing examples, discuss why rodent adaptive radiation has been so successful: Ancestral rode n t , Masillamys

Mouse-like rodents

Rodents make up 40% of mammalian species, making them the most successful of the mammalian groups. Fossils with distinctive rodent features first appeared about 66 million years ago, and during their evolution they have spread to all continents except Antarctica and most islands. They are morphologically generalised and highly adaptable, occupying a wide range of habitats including deserts, forests, and Arctic tundra. Their life histories are highly varied and they exhibit a wide range of adaptations for a range of niches (below). In some cases, distantly related species have occupied the same type of habitat and niche in widely separated regions, e.g. the kangaroo rat in western North America deserts (beaver-like rodents) and the jerboa in African deserts (mouse-like rodents).

Rhea

New genetic studies have now cast doubt on this interpretation. Mitochondrial DNA (mtDNA) evidence now suggests kiwis are most related to the extinct elephant bird from Madagascar and slightly less closely related to emus in Australia. However, the ancestor to the kiwi arrived in New Zealand long after New Zealand separated from the rest of Gondwana. Ancestral kiwi must therefore have flown there. Moas are now thought to be closely related to tinamous (South America), which can fly. Ostriches were thought to be closely related to elephant birds but mtDNA now suggests they diverged from the other ratites early. The conclusions from these new findings suggest that the ratites evolved from flighted birds that flew between continents and independently evolved flightlessness at least six times.

*Tinamous from South America were until recently thought to be related to but not part of the ratite group. New evidence suggests they should be included in ratites.

Elephant bird Two species, Madagascarextinct,

Birds evolved from a theropod dinosaur ancestor about 150 million years ago.

112

Ostrich Struthio camelus, Africa Emu Dromaius novaehollandiae, Australia.

Kiwi Five species, New Zealand.

SI brown kiwi

MoaRheaOstrichCassowaryEmu21:

diverge from the line to the rest of the birds about

It had long been thought that the geographical distribution of modern day and extinct ratite species could be explained in terms of continental drift. The "rafting hypothesis" suggests that the ancestral ratite population existed at a time when the southern continents of South America, Africa, and Australia (and their major offshore islands) were joined as a single land mass called Gondwana. As the continents moved apart as a result of plate tectonics, the early ratite populations were carried with them.

Eleven species (Lambert et al 2004*), all extinct, New Zealand.

* Lambert et al. 2004. “Ancient DNA solves sex mystery of moa.” Australasian Science, 25(8), Sept. 2004, pp. 14-16.

Ratite phylogeny

Cassowary Three species, Australia & New Guinea.

Birds evolved from a saurischian (small theropod) dinosaur ancestor about 150 million years ago (below)

Moa

Rowi

ElephantTinamouMoa bird OstrichRheaCassowaryEmuKiwiOtherbirds

Tinamou (can fly)

Little spotted kiwi

4: Megalapteryx C F B D E G A K H J I L A

Rhea Two Southspecies,America.

2: Pachyornis

All other living birds

Ratites 100 million years ago.

kiwi

Ratites diverged from other birds between 90 and 70 million years

Moas diverged from tinamous about 55 million years ago.

Ratites

Moa

3: Dinornis

NI brown kiwi

Key Idea: The ratites are group of birds descended from a single common ancestor that lost the power of flight very early on in their evolutionary development. Ratites are flightless birds that possess two features that distinguish them from other birds; a flat breastbone (instead of the more usual keeled shape) and a primitive palate (roof to the mouth). Fossil evidence indicates that the ancestors

From Mitchell et al LINK 108

Letters commonindicateancestors

of ratites were flying birds living about 80 million years ago. These ancestors also had a primitive palate, but they possessed a keeled breastbone. Flightlessness in itself is not unique to ratites; there are other birds that have lost the power of flight, particularly on remote, predator-free islands. All ratites have powerful legs, and many, such as the emu, can run very quickly.

Anomalopteryx

Moa

ago.75mya 50 mya 25 mya Present

Moa

Great spotted kiwi

Mesozoic Era Cenozoic Era

Divergent Evolution in Ratites

Fossil evidence suggests that ratite ancestors possessed a keeled breastbone and an archaic palate (roof of mouth)

(b) On the phylogenetic tree opposite, circle the branching marking the common ancestor of emus and kiwi

(b) Which ratite group is actually the closest related to the ostrich?

3. (a) Name two other flightless birds that are not ratites:

(b) Why should tinamous be included in ratites?

(b) Why are these other flightless species not considered part of the ratite group?

5. (a) On the phylogenetic tree opposite, circle the branching marking the common ancestor of moa and kiwi.

6. (a) Based on the rafting hypothesis which ratite would you expect to be most closely related to ostriches?

2. Describe two anatomical changes, common to all ratites (excluding tinamous), which have evolved as a result of flightlessness. For each, describe the selection pressures for the anatomical change:

1. (a) Describe three physical features distinguishing all ratites (excluding tinamous) from most other birds:

7. The diversification of ratites may still be explained in part by continental drift. Use the data on the opposite page to suggest a possible sequence of events for the distribution of ratites:

4. Kiwis are ratites that have remained small. They arrived in New Zealand long after the moa. What part might this late arrival have played in kiwi species remaining small?

(a) Anatomical change: Selection pressure: (b) Anatomical change: Selection pressure:

The Rate of Evolutionary Change

LINK 108 WEB 113

113

Each gradualundergoesspecieschangesinitsgeneticmakeupandphenotype.

Key Idea : New species may arise gradually through accumulation of differences over a long period of time or they may arise relatively suddenly Two common models, gradualism and punctuated

(a) What term given to this lack of evolutionary change?

3. Some species, such as sharks, horseshoe crabs, and tuatara, apparently show little evolutionary change over long periods of time (hundreds of millions of years).

ISBN: 978-1-927309-56-8

KNOW

154

1. Suggest the kinds of environments that would support the following paces of evolutionary change: (a) Punctuated equilibrium: (b) Gradualism:

New species New species New speciesParent species Parent species

New species bud off from the parent species and undergo rapid followedchange,bya long period of stability. New divergesspeciesfrom the parent species.

(b) Suggest why such species have apparently changed little over evolutionary time:

Photocopying Prohibited

2. In the fossil record of early human evolution, species tend to appear suddenly, linger for often very extended periods before disappearing suddenly. There are few examples of smooth inter-gradations from one species to the next. Which of the models (punctuated equilibrium or gradualism) best describes the rate of human evolution?

There is abundant evidence in the fossil record that, instead of gradual change, species stayed much the same for long periods of time (called stasis). These periods were punctuated by short bursts of evolution which produce new species quite rapidly. According to the punctuated equilibrium theory, most of a species’ existence is spent in stasis and little time is spent in active evolutionary change. The stimulus for evolution occurs when a crucial aspect of the environment changes, creating new selection pressures.

Punctuated equilibrium

Phyletic gradualism

equilibrium, are proposed for the rate at which new species arise (below). It is likely that both operate at different times for different taxa in different situations. There is evidence for both models in the fossil record and in living populations.

New species New species New speciesParent species Parent species

Phyletic gradualism assumes that populations slowly diverge by accumulating adaptive characteristics in response to different selective pressures. If species evolve by gradualism, there should be transitional forms seen in the fossil record, as is seen with the evolution of the horse. Trilobites, an extinct marine arthropod, are another group of animals that have exhibited gradualism. In a study in 1987, a researcher found that there was a gradual change in eight lineages over a period of three million years.

A typical pattern

New Zealand is separated into three main islands and numerous small ones. Geological activity still continues, producing a variety of landscapes including snow fields, high rainfall differences between east and west, and low land plains.

How did each of the following geological events provide an opportunity for speciation:

New Zealand assumes roughly its present shape. Changes in sea level during glacials connect the islands. Kakariki arrive and diversify.

separates

40 mya

The rise and fall of New Zealand

Present day

(b) The Oligocene

Key Idea: New Zealand's geological history and early isolation from other land masses has played a significant role in the evolution of New Zealand's unique flora and fauna. New Zealand became isolated from other land masses around 65 mya when the land mass that became New Zealand split away from Gondwana (below). The isolation resulted in the

25 mya

150-100 mya

The Geological History of New Zealand

Plate boundary forms and Tasman sea begins to open. Dinosaurs still predominate and mammals are yet to spread widely. New Zealand is well forested with many available niches. Its most ancient organisms are present including geckos, frogs, tuatara, and snails.

(a) New Zealand from Gondwana:

2 mya to 0.5 mya

Timeline

The Kaikoura Orogeny begins, uplifting the Southern Alps, producing the first alpine environment in 50 million years. Many plants and animals move into the vacant niches including cicada, kea, and buttercups.

Erosion reduces New Zealand to less than half its previous size.

114 WEB 114 LINK 115

New Zealand has had a varied geological history, rising from below the sea, becoming half the size of Australia, and sinking to almost nothing before rising again to form high snow covered mountains. The New Zealand landmass is the highest point of a much greater submerged microcontinent known as Zealandia. The rise and fall of Zealandia allowed the organisms present to colonise new landscapes, before retreating to scattered islands. Large scale changes to the sea level (more than 100 m) during glacials has contributed to this fragmentation, periodically joining and separating the islands.

New Zealand land mass has eroded to its smallest size (known as the Oligocene Drowning). Many small islands give opportunities for speciation, e.g. geckos and snails.

evolution of a unique array of organisms. With the exception of three native bat species (one extinct), no land mammals were present and niches occupied by mammals elsewhere in the world were, in New Zealand, filled by birds and insects. The geologic activity of New Zealand over its history has provided ample opportunities for speciation of these taxa.

New Zealand is joined to the toincludingaredinosaurshaveGondwana.supercontinentMammalsnotyetdiversified,stillrule.Birdsevolving.AncientplantspodocarpsspreadancestralNewZealand.

5 mya

Drowning:

70 mya

Last glacial (20,000-18,000 years ago)

f Sea level rose as the climate warmed and the polar ice melted.

Pliocene (~5 to 2.5 mya) and some of the interglacials

populationsMainlandThese

Area portrayed below IslandNorth NorthlandIsland

f Many populations underwent gene pool changes as they responded to the specific natural selection pressures of smaller habitats.

Snow and ice fields

The sea bed is exposed for thousands of years and is recolonised by terrestrial organisms.

During this phase, the distribution ranges of many species were altered. New climatic conditions altered habitat, in some cases drastically, and generated new selection pressures. There was opportunity for species to increase their distribution to what would later become offshore islands.

Changes in Landscape and Speciation

Traps Is.

f New Zealand’s shoreline was 60 m lower than it is today so the total landmass was greater than today.

Warm interglacial periods

Puysegur Is.

Steppe loess zone

GlaciersTundraGrasslandWoody(grassland)vegetationzoneandsnow

During New Zealand's geological history, periodic cycles of volcanic activity, fragmentation, and sea level change isolated founder populations and exposed them to new selection

Photocopying Prohibited

Significance

Aupouri Is.

ManukauStraightStrait

The diagram above shows New Zealand during a glacial period with the sea level 60 m below present level, exposing large areas of sea bed which was colonised by vegetation.

Three Kings Is.

Sea level drops by 60 metres

Poor Knights Is.

f More islands and archipelagos (island chains) were created.

115

KnightsPoorBarrierGreatIs.Is. Ahipara

f The podocarp forests, which covered most of the North Island in more recent times, were restricted to north of Auckland and along the coastline in some regions

f Islands were isolated by large stretches of water.

LINK 116 WEB 115

Ranfurly Is.

isolated populations may undergo evolutionary changes that are different from each other. Present-day sea level

Three Kings Is.

grasslandSubalpinevegetationWoody

pressures, accelerating the pace of evolutionary change. New Zealand's fragmentation into islands through sea level rise (~30 mya), cooling climate (from ~10 mya), and increasingly mountainous landscape (from ~5 mya) have been associated with many speciation events and has resulted in great diversity and a large number of endemic species.

ISBN: 978-1-927309-56-8

Key Idea: New Zealand's fragmentation as a result of changes in sea level created conditions favouring the divergence of many local species

f The majority of the landmass was covered by snowfields or tussock grasslands.

f The southern cool-temperate beech forests were widespread. Large areas of the exposed seabed are thought to have been covered by this forest.

Populations on the mainland and the offshore island are separated by the physical barrier of the sea. populationsIsland

Mernoo Is.

156

Mainland and island populations remix

Glacial periods

f This period was important for speciation events in New Zealand.

North Cape

Paralissotes planus Paralissotes oconnori

Paralissotes mangonuiensis

Paralissotes reticulatus

The four species of closely related stag beetles found in the upper North Island are thought to have shared a common ancestor prior to the Pliocene rise in sea level. When the climate warmed and the sea level rose, a chain of islands (an archipelago) was created, isolating parts of the population. Over thousands of years of isolation with different selection pressures, each group evolved separate species status. Since the fall in sea level, these populations have been able to remix in many cases, but the gene pool of the species remains intact because reproductive isolating mechanisms are now in place. The point of origin for each species can be estimated by comparing their present distribution with that of Pliocene Northland.

Current distribution of Paralissotes genus Paralissotes

Cape Maria van Diemen

(a) Interglacial periods:

1. How have the following influenced New Zealand's landscape?

Sea level rises in New Zealand during the Pliocene isolated invertebrate populations on an archipelago and contributed to the emergence of several species from a common ancestor. The stag beetles (genus Paralissotes) are an example of this.

(b) Glacial periods:

(b) Describe the likely event that allowed these two species to occupy the same region south of Auckland:

3.0ccRudolph89

Stag beetles

2. (a) Consult the map of the Northland region during the Pliocene and determine what land mass P. planus and P. reticulatus were restricted to during their divergence into separate species:

Zone of (sympatricoverlapdistribution) Auckland Whangarei

New Zealand's giant land snail (Powelliphanta species) are large, nocturnal, carnivorous snails. They are a very diverse genus with at least 21 species and 51 subspecies. Today most of the species are found in northwest Nelson and north Westland, but they are also located in other

Key Idea : There are many species of New Zealand Powelliphanta snails. The diversity has arisen through multiple speciation events in diverse habitats.

peaks

regions (see map below). The snails were once widespread in New Zealand, dispersing into a variety of habitats ranging from alpine grasslands to lowland forests. This diversity of habitats coupled with geographic isolation has resulted in a large amount of speciation. Some isolated populations were trapped on mountain 'islands', cut off from other populations by difficult terrain or expanses of ocean during periods of high sea level.

The superb land snail, P. superba, is found in forest above 450 m in the Heaphy-Aorere area of Northwest Nelson.

P. hochstetteri, are

Photocopying Prohibited

Five subspecies snail, confined forested around and Marlborough Sounds.

The geographic distribution of giant land snails in New Zealand

the

DoC-KW

Marchant’s

Gillies’ land snail, P. gilliesi aurea, is found over a wide range of altitudes in the Golden Bay area of Northwest Nelson.

Two other groups of giant land snails known as kauri snails and flax snails are distributed within Northland and a few offshore islands.

Most current populations are restricted to the southern North Island and the northern South Island, but in past times their distribution extended as far north as Waikato.

1. Describe the geographical factors contributing to the evolution of so many species of giant land snails in New Zealand: 2. (a) Name the type of speciation pattern observed here: (b) What evidence is there to support your answer? LINK 114 LINK 115 WEB 116

Nelson

land snail, P. marchanti, is only found above 900 m. It is the most widely distributed species (Lake Waikaremoana to Mt Taranaki). DoC-VV

Speciation in Giant Land Snails Marchant’s land snail Travers’ land snail Hochstetter’s land snail Gillies’ land snail Superb land snail Oparara land snail Woodformed land snail Ross’ land snail Fiordland land snail Ross’ and Speden’s land snail

116 4 2 2 22 2 3 5 3 7 8 109 1 1 1 6 1.

158

The map on the right shows the distribution of 10 Powelliphanta species. Note that Ross’ land snail has a split distribution (locations 8 and 10) and is sympatric with Speden’s land snail.

10.

to high

of Hochstetter’s land

Mokihinui River RadiantRange

ABC N N X X

Hochstetter ’s land snail

RiverGlasgow Range MatiriRange

Ngakawau

CookStrait Island South Island

North

Hochstetter’s land snail (subsp.)

landTravers’snail

Powelliphanta lignaria lignaria

Powelliphanta hochstetteri hochstetteri

Gillies land snail

The North Island and South Island are separated by the Cook Strait. This 20 km stretch of ocean forms an impassable barrier and may only be crossed during periods of low sea level as in past ice ages.

KEY

Westport

(c)(b)(a)

Woodformed land snail (subsp.)

(d) Explain what the formation of viable hybrids tells you about the reproductive isolation of these subspecies:

These giant land snails cannot cross water. The Westland region of the South Island has a high rainfall with many rivers and their tributaries dissecting the rugged landscape. These water channels pose impassable barriers for the snails and cause the geological isolation of small pockets of the population. This has had the effect of causing a high degree of subspeciation in this region.

4. Two subspecies of the woodformed land snail, P. lignaria lignaria (which has a strong banding pattern on its shell) and P. lignaria unicolorata (which has few bands), were separated by the Mokihinui River. In 1929, the Murchison earthquake caused a temporary dam on the Mokihinui River. When the flood waters were released, the two subspecies were mixed near the river mouth. Colonies of hybrids now occur on both sides of the river (marked by X on diagram A above).

Karamea River

3. Describe the principal geographical isolating mechanism for each of the examples (A to C) in the diagram above:

BullerRiver

(b) What is a hybrid?

Little Wanganui River

Woodformed land snail (subsp.)

Powelliphanta gilliesi 300 metres

Lowland

Powelliphanta lignaria unicolorata

Karamea

(a) What effect did the earthquake have on the geographical isolation of these two subspecies?

Highland

Some populations of land snail are separated by different ecological requirements. One subspecies of Hochstetter’s land snail are found only above 300 m while most Gillies’ land snails occupy lowland habitats.

High Lowlandalpinecountry/

Beginningmya.ofthe

kaka/kakapo(unknown)AustralianancestorProto-Proto-kaka

Kea (Nestor notabilis) inhabits mountain regions of the South Island. They feed on fruit and insects, and are also scavengers.

Low sea level during glacials. Isolation of the North Island from the South Island by the formation of Cook Strait.

New Zealand is well-forested 60-80 mya, allowing the ecological divergence of the proto-kaka and kakapo into tree-dwelling aboutthedivergenceallowsTheground-dwellingandtypes.newalpineenvironmenttheecologicalofthekakaandkeafromtheproto-kaka3mya.

Source: E.J. Grant-Mackie (Thames High School) and J.A. Grant-Mackie (Geology Dept, University of Auckland), based on mDNA studies by Prof. Geoff Chambers and Dr Wee Ming Boon (Victoria University, Wellington).

Geological event

DoC-RM

KNOW

Speciation event

Photocopying Prohibited

Kaka (Nestor meridionalis) has a North Island and a South Island subspecies. They feed on fruit, honeydew, and insects.

break-up of the Gondwana segment containing New Zealand about 100 mya.

unknown Australian ancestor about 100 mya. The origin of this proto-kaka/kakapo was associated with the break-up of Gondwana and formation of the Tasman Sea, when New Zealand moved away from Australia and became isolated. The kakapo split from this lineage 60-80 mya and is our most ancient parrot. Kaka split from the kea line some 3 mya and an early member migrated to produce the now-extinct Norfolk Island kaka. About 400,000 years ago the North and South Island kaka differentiated.

Origin of New Zealand Parrots

ISBN: 978-1-927309-56-8

Kakapo (Strigops habroptilus) is a ground-dwelling (flightless) night parrot that was once widely distributed throughout Fiordland and Stewart Island. They feed on berry fruit.

117 LINK 114 WEB 117

Australia and New Zealand become separated by the formation of the Tasman Sea about 80

160

kakapo kea Norfolk Island kaka (extinct) NorthkakaIsland SouthkakaIsland

Vicariance: kaka splits into the North Island and South Island sub-species about 0.4 mya.

The Southern Alps begin to rise around 5 mya. Formation of the Manawatu Strait splits New Zealand.

Vicariance: Unknown Australian ancestor gives rise to proto-kaka/kakapothe group about 100 mya. Vicariance is a term to describe the geographical separation of a population. It has been important to speciation events in New Zealand.

Key Idea: The kakapo, kea, and kaka evolved from an ancestor that lived around 80 mya. The rise of the Southern Alps provided new habitat occupied by the ancestor of the kea. Recent mitochondrial DNA (mtDNA) studies at Victoria University confirm the existence in New Zealand of two distinct groups of parrots: kakapo-kaka-kea, and the various kakariki (5 species). This research provides an excellent example of the use of DNA analysis to determine evolutionary relationships. The kakapo-kaka-kea group originated from an

kaka

2. (a) Describe the two habitats in which the kaka and kea species evolved:

Separation from Australia

TasmanmyaSea

6. The kakapo is described as our most ancient parrot. Why do they deserve this label?

WarmtodayinterglacialAlpineTundraForestscrub

3. Identify the species that became cold-adapted:

Late Miocene Early Pleistocene Holocene

1. What role did geographical isolation play in the divergence of the proto-kaka/kakapo from its Australian ancestor?

Australia and New Zealand are separated by the formation of the Tasman Sea 80

5. It has previously been postulated that the kakapo may be related to the Australian night parrots and/or Australian ground parrots, but this has not been supported by modern DNA studies. Suggest a reason for the similarities (appearance, ground nesting, poor flight) between these Australian parrots and the kakapo:

Kaka

Period warmer than today 10 mya Glaciation~2.5mya

4. Why do the modern kaka and kea species in the South Island not interbreed?

Australia New Zealand NorthkakaIs. SouthkakaIs. KeaKeaKakakakapoand Manawatu Strait

(b) When did these two different habitats emerge?

162

Curved beak wren

Spent sucrryingtimeup and down tree trunks, probing in crevices for grubs with its curved beak.

Curved beak wren Stout legged wren IslandNorth IslandNorth IslandNorthIslandSouth IslandSouth IslandSouth

Key Idea: The ancestor of New Zealand wrens underwent an adaptive radiation about 20 mya. Only two living species remain due to habitat loss and predation.

Extinction phase during land area reduction due to submergence (50-25 mya)

WrenStewartIsland

ISBN: 978-1-927309-56-8

PleistoceneRecentPlioceneMioceneOligocene 10,00001.8million5million24million ?

118

Rock Wren Fiordland SouthernAlps Rifleman

Common ancestor of the New Zeland wrens

Stout legged wren Stephens Is. wren Bush (recentlywrenextinct) Rock wren Rifleman

Lived and foraged in grass equivalent(ecologicalunderbrushandof a field mouse).

Lives in subalpine areas, undersurvivingtussock,amongfeedingrocksandandwinterthesnowlayer.

Adaptive Radiation in Wrens

Secondary radiation further divergence into new species and sub-species

Many thanks to Ewan Grant-Mackie, Thames High School, and Prof. J.A. Grant-Mackie, Geology Dept, Auckland University, who supplied the information for this exercise.

Species survives to present

Can/could fly FlightlessSpecies is extinct

Stephens Is. Wren Bush

Lives and feeds in the bush, picking insects branchesfromand trunks of trees.

The New Zealand wrens have been isolated from their probable ancestral stock in Australia for more than 60 million years. Although they are called wrens because they resemble true wrens, they belong to an ancient suborder with no living close relatives. The endemic family to which they belong includes the rifleman, the rock wren, and the bush wren, as well as a number of extinct species. New Zealand wrens are small, insectivorous, and flightless (or with poor flying ability). The ancestral wren was almost certainly insectivorous since all the descendants are. There may well have been several related species, of which the ancestral wren was one, living in

Both species were ground groundsearchingdwelling,theforinsects.

isTimeNOTE:scalenotlinearKEY

Lived and foraged in the insectssearchingbushforinthe air and on the ground.

LINK 114 LINK 115

different habitats throughout early New Zealand. The existing wren family dates from a time of extensive adaptive radiation 20 mya. They were once found throughout New Zealand, but their distribution is now much more restricted. Although all insectivorous, the living and extinct wrens exploited different habitats and feeding niches Fossils of extinct species can illustrate past land connections. Fossils of the Stephens Is. wren (extinct) have been found in both the North and the South Islands, showing that there was a land connection between these islands in the past. The two species of stoutlegged wren may have undergone allopatric speciation 3-5 mya when changing sea levels separated North and South Islands. Later similar events could also explain the evolution of separate sub-species of bush wrens and rifleman. Years ago

NOTE: On the diagram, the timescale for the emergence of new sub-species, species, and genera is not linear. As a general rule among birds, new sub-species emerge after 0.5-2 million years of separation, new species after 2-10 million years, new genera after 10-20 million years and new orders with 60-80 million years of separation.

Photocopying Prohibited

Primary radiation the first radiation from a common ancestor (22-18 mya).

New Zealand geology and adaptive radiation of New Zealand wrens

The reduction in size and break-up of the single land mass had a profound effect on the evolution of the wrens, greatly reducing their range of habitats and causing selective extinctions:

1. Adaptive radiations have occurred on several occasions in the New Zealand wrens:

The reduction in species diversity

When the New Zealand land mass was largely submerged during the Oligocene, some animals would have retreated to islands of high ground, but would have perished as these became submerged. As a result, many species were lost.

The reduction in genetic diversity

(d) Curved beak wren:

(b) Bush wren:

Not only were species lost, but the genetic diversity of remaining populations would have been severely depleted, with few individuals in a species surviving to pass on their genes. This population bottleneck effect occurs when a very small sample of the total species gene pool manages to survive. When the sea levels dropped again, the survivors moved in to occupy newly available niches.

New Zealand shoreline

3. Describe the niche of each wren, including reference to the way in which they may have differentiated:

(a) What is the difference between primary radiation and secondary radiation?

The adaptive radiation of the New Zealand wrens was a consequence of the break up of the New Zealand land mass during the Oligocene period. Earlier species, as yet undiscovered, may also have existed at this time. A this time (25-30 mya), New Zealand was almost completely submerged, and existed only as a chain of small islands, with a land mass only 18% of what it is today. This was the result of rising sea levels and land subsidence over a period of 5 million years.

New Zealand during the Oligocene 25 – 30 million years ago

OligocenePresentday

2. The wrens have undergone two periods where extinctions have occurred; an early one more than 25 million years ago, followed by a recent extinction phase.

(a) Rock wren:

(e) Rifleman:

(b) What was the most likely cause for the recent extinction phase of some of the wren species?

(a) What event caused the early extinction phase?

(b) When did the primary radiation occur following the population bottleneck?

4. Explain how geological events in New Zealand affected the radiation of the wrens:

The adaptations of the Hebe species reflect their different habitats. Species at lower altitude have larger leaves. High altitude species have scale leaves. Some species have polyploid chromosome numbers, indicating instant speciation and suggesting that the Hebe group is still evolving

Hebe macrocar pa Mainly montain forests

Species that prefer high altitude may have first colonised the slopes of the original volcanic cone of Kaitake.

5. Suggest why Pouakai has a greater number of Hebe species than Mt. Taranaki, even though it has a lower altitude:

Hebe species

ISBN: 978-1-927309-56-8

Hebe odora (erect form)Mainly red tussockland

Current summit: 684m Cone: 525,000 years old

Scale leaves on whipcord foliage (greatly enlarged)

4. What aspect of the Hebes in Taranaki provides evidence that the group is still evolving rapidly?

Hebe tetragona

1. What process has resulted in instant speciation in Hebe species:

Hebe tetragona Exposed tussock herbfield Hebe “egmontiana” Mainly subalpine scrub & shrubland

Key Idea: New Zealand Hebe species show extensive adaptive radiation. Their distribution around Mt Taranaki reflects past colonisations and current rapid speciation. Many of New Zealand’s angiosperm groups show evidence of spectacular adaptive radiations. The Hebe group of plants consists of ~150 species in 5 genera. Most (2/3) of the species are in a single genus, Hebe, which includes about 20 undescribed polyploids. Hebes share a single common ancestor (they are monophyletic). Recent molecular studies

Hebe species in Taranaki

The current high altitude species on Mt. Taranaki may have originated on Pouakai or Kaitake. Some of the hebes on Pouakai have not yet colonised Mt. Taranaki because of its more recent volcanic activity.

Current summit: 1337m Cone: 250,000 years old

Present a the following locations: Taranaki

Mt. KaitakePouakai

Evolution in Hebe119 LINK 103

Current summit: 2518 m Cone: 70,000 years old

2. How would high altitude species have first colonised the slopes of Kaitake, despite its low (684 m) summit?

3. What aspect of the Hebes in Taranaki indicates that the group has undergone adaptive radiation?

Habitat

Habitat preference and distrib ution of Taranaki Hebes

Large leaves on foliage

Mount Taranaki Pouakai Kaitake

volcanicOriginalrapidly.cone

Some Hebe species may have migrated to the newly forming Pouakai where they became established. Failure to do so would have led to their extinction on the older cone.

“egmontiana”Hebe

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Mainly lowland, stream-sides

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Hebe odora (prostrate form)Exposed tussock herbfield Hebe venustula Subalpine shrubland

suggest that they arrived in New Zealand less than 5 mya from an ancestor in Gondwana or migration from South-east Asia. The pattern of current Hebe distribution in the region of Mt. Taranaki indicates that some of the Hebe species found at high altitude may have first colonised the once high slopes of Kaitake and Pouakai from mountains elsewhere in the North Island. These volcanic remnants once had summits much higher than their current summits.

Hebe stricta

Evolution in New Zealand

You Know So Far: Patterns in Evolution

120

HINT: Include clear definitions and describe both rates and patterns of change and patterns of change

Patterns of evolution

HINT: Give detail of species involved and geographical events relevant to the example.

Discuss the pattern of evolution illustrated by this example. In your answer you should consider the selection pressures acting on ichthyosaurs and dolphins during their evolution. You may use more paper if required.

Dolphin

1. Large marine reptiles known as ichthyosaurs were common in ancient New Zealand waters. Their outward appearance is similar to the dolphins that inhabit New Zealand waters today, and they probably behaved in very much the same way. Evidence suggests that at least some species of ichthyosaur gave birth to live young at sea, as dolphins do now.

NZ rifleman

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2. New Zealand once had at least six species of wren, most of which evolved from a common ancestor between 22 and 18 million years ago. Only two species are living today. This large number of species is related to the break up of the New Zealand land mass during the Oligocene.

Describe the pattern of evolution shown in wrens. Explain how this pattern arises and discuss the factors that could have led to this pattern in New Zealand wrens. You may use more paper if required.

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Ichthyosaur

NCEA Style Question: Patterns in Evolution

3. The diagrams on the right represents two models showing the rate of evolutionary change.

adaptive radiation common vicariancepunctuatedphyleticdivergentconvergentancestorevolutionevolutiongradualismequilibrium

Cactus Euphorbia

4. The two plants shown right are unrelated. The left hand image shows a cactus from North America, while the right hand image shows a Euphorbia from Africa. Both these plants live in deserts.

Pattern A

(b) Describe the features of this model:

B A model for the evolution of lineages in which long periods of stasis are interrupted by brief periods of rapid speciation

(d) Describe the features of this model:

(a) Name the model represented by pattern A:

KEYProhibitedTERMS

A The most recent individual from which all organisms in the group are directly descended.

AND IDEAS: Patterns of Evolution

(a) Identify the pattern of evolution displayed by these plants: (b) Describe the environments associated with the adaptations.

E A model for the evolution of different forms over a long period of time but with only slight changes occurring between successive generations

C The geographical separation or fragmentation of a population.

Pattern A Pattern B

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F Evolutionary process in which a species or related species follow different evolutionary pathways to eventually become less related

G Evolution in unrelated species occupying similar niches that causes them to arrive at similar structural, physiological and behavioural solutions

1. Test your vocabulary by matching each term to its correct definition, as identified by its preceding letter code.

D A form of divergent evolution in which there is rapid speciation of one ancestral species to fill many different ecological niches

2. Distinguish between vicariance and dispersal as important mechanisms in the evolution of species:

ISBN: 978-1-927309-56-8

KNOW

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DNA encodes the genetic instructions of all life. The form of these genetic instructions, called the genetic code, is effectively universal, i.e. the same combination of three DNA bases code for the same amino acid in almost all organisms. The very few exceptions in which there are coding alternatives are restricted to some bacteria and to mitochondrial DNA.

Other bacteria Domain CyanobacteriaBacteria

Molecular phylogenetics has enabled scientists to clarify the very earliest origins of eukaryotes and to recognise two prokaryote domains. Powerful evidence for the common ancestry of all life comes from the commonality in the genetic code and from the similarities in the molecular machinery of all cells.

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Chloroplasts have a bacterial origin

There is a universal genetic code

Bacteria lack a distinct nucleus and cell organelles. Features of the cell wall are unique to bacteria and are not found among archaea or eukaryotes. Typically found in less extreme environments than archaea.

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(manyProteobacteriapathogens)

bacteriaHyperthermophillic

Mitochondria have a bacterial origin

Evidence from mitochondrial gene sequences, ribosomes, and protein synthesis indicate that mitochondria have a prokaryotic origin. Mitochondria were probably symbiotic inclusions in an early eukaryotic ancestor.

Cyanobacteria are considered to be the ancestors of chloroplasts. The evidence for this comes from similarities in the ribosomes and membrane organisation, as well as from genomic studies. Chloroplasts were acquired independently of mitochondria, from a different bacterial lineage, but by a similar process.

Key Idea: Key features shared by all life forms support the hypothesis that life on Earth evolved from a common ancestor. Our knowledge of how organisms are related has grown rapidly in recent decades due to new techniques in molecular phylogenetics. Such techniques compare the DNA, RNA, and proteins of organisms to establish evolutionary relationships.

LINK 124 WEB 123 EII

The Common Ancestry of Life

DomainFungiEukarya

Archaea superficially resemble bacteria but similarities in their molecular machinery (RNA polymerase and ribosome proteins) show that they are more closely related to eukaryotes.

Xiangyux

Eukaryotes have linear chromosomes

of cells that support a common ancestry of life: (c)(b)(a)

Bacteria that gave rise to mitochondria

PlantsAlgae

Eukaryotic cells all have large linear chromosomes (above) within the cell nucleus. The evolution of linear chromosomes was related to the appearance of mitosis and meiosis.

(PD)

Archaea resemble bacteria but membrane and cell wall composition and aspects of metabolism are very different. They live in extreme environments similar to those on primeval Earth.

Animals

Domain Archaea

Ciliates

1. machinery

Suggest why scientists

Identify three features of the metabolic

Eukarya (the eukaryotes) are characterised by complex cells with organelles and a membrane-bound nucleus. This domain contains four of the kingdoms recognised under a traditional scheme.

Bacteria that gave rise to chloroplasts

In all living systems, the genetic machinery consists of selfreplicating DNA molecules. Some DNA is transcribed into RNA, some of which is translated into proteins. The machinery for translation (left) involves proteins and RNA. Ribosomal RNA analysis support a universal common ancestor.

Eukaryotes have an archaean origin

2. believe that mitochondria were acquired before chloroplasts:

RCN EII

Living systems share the same molecular machinery

Last CommonUniversalAncestor(LUCA)

Cytochrome c

The study of developmental processes and the genes that control them gives insight into evolutionary processes. This field of study is called evolutionary developmental biology (evo-devo).

Developmental evidence

Chronometric dating

Comparative anatomy

Geology

Comparative anatomy examines the similarities and differences in the anatomy of different species. Similarities in anatomy (e.g. the bones forming the arms in humans and the wings in birds and bats) indicate descent from a common ancestor.

The Evidence for Evolution

DNA can be used to determine how closely organisms are related to each other. The greater the similarities between the DNA sequences of species, the more closely related the species are.

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Protein evidence

KNOW

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Radiometric dating techniques (such as carbon dating) allow scientists to determine an absolute date for a fossil by dating it or the rocks around it. Absolute dating has been used to assign ages to strata, and construct the geological time scale.

be explained by speciation, extinction, and continental drift. The biogeography of islands, e.g the Galápagos Islands, provides evidence of how species evolve when separated from their ancestral population on the mainland.

Similarities (and differences) between proteins provides evidence for determining shared ancestry. Fewer differences in amino acid sequences reflects closer genetic relatedness.

DNA comparisons

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EVOLUTION

Key Idea: Evidence for the fact that populations evolve comes from many fields of science. Recall that evolution is simply the heritable genetic changes occurring in a population over time. There are two important points to take from this definition. The first is that evolution refers to populations, not individuals. The second is that

Geological strata (the layers of rock, soil, and other deposits such as volcanic ash) can be used to determine the relative order of past events and therefore the relative dates of fossils. Fossils in lower strata are older than fossils in higher (newer) strata, unless strata have been disturbed.

ISBN: 978-1-927309-56-8

the changes must be passed on to the next generation (i.e. be inherited). The evidence for evolution comes from many diverse branches of science and includes evidence from both past and present populations. Drawing on evidence from a number of scientific disciplines helps to build a robust explanation for the evolutionary history of taxa.

Soft material such as the cartilagineous skeletons of sharks don't fossilise well. Often the only remains are their teeth (above).

2. Explain why the rapid burial of an organism important in the formation of fossils:

Fossilisation best occurs when an organism dies in a place where sediment can be laid down relatively quickly. This is often an aquatic environment, e.g. an estuary, but it can be caused by rapid burial, e.g. by a landslide or volcanic ash.

biased

requires the normal processes of decay to be permanently arrested. This can occur if the organism's remains are isolated from the air or water and decomposing microbes are prevented from breaking them down. Fossils provide a record of the appearance and extinction of organisms, from species to whole taxonomic groups. Once this record is calibrated against a time scale (by using a broad range of dating techniques), it is possible to build up a picture of the evolutionary changes that have taken place.

After burial, the bones are subjected to pressure. Minerals in the surrounding sediments move into the bones and replace the minerals in them.

Key Idea: Fossils are the remains of long-dead organisms that have escaped decay and have, after many years, become part of the Earth’s crust. A fossil may be the preserved remains of the organism itself, the impression of it in the sediment (a mould), or marks made by it during its lifetime (trace fossils). For fossilisation to occur, rapid burial of the organism is required (usually in waterborne sediment). This is followed by chemical alteration, whereby minerals are added or removed. Fossilisation

3. Explain why the fossil record is towards marine organisms with hard parts:

Erosion of the sediments exposes the fossils on the surface.

After death, the flesh may rot or be scavenged, but hard materials, usually bones and teeth, are able to remain long enough for burial.

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Fossils125

1. Describe how a fossil forms:

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f Trilobites (meaning three lobes) are a fossil group of extinct marine arthropods. They first appeared in the fossil record near the beginning of the Cambrian (520 mya) and disappeared in the mass extinction at the end of the Permian (250 mya).

ISBN: 978-1-927309-56-8

and streamlined bodies aided swimming in pelagic (open ocean) forms.

5. What fossil evidence do we have that trilobites were a diverse group adapted to many different

4. (a) Explain the importance of index fossils in determining relative time lines: (b) Why do trilobites make good index fossils?

Some fossils act as index fossils

Elongatedniches?

Spines provided defence from attack and stabilisation on loose surfaces.

f Trilobites make excellent index fossils because they are easily recognisable, abundant in the fossil record, and different families are characteristic of different geographic distributions and different time periods.

f An index fossil is a fossil that is characteristic of a particular span of geologic time or environment. Index fossils help scientists with relative dating (placing rock layers in a relative order to each other), define boundaries in the geologic time scale, and correlate strata from different regions.

f The trilobite fossil record provides evidence of several evolutionary trends in the different lineages. These included streamlined shape in swimming forms, broadening of the head in filter feeders, improvement in the ability to curl up into a defensive ball, decreased size, and the evolution of spines as defences (below).

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f They were a very diverse group and underwent several radiations during the Cambrian, inhabiting a wide range of marine environments and exhibiting diverse life strategies. The wide diversity in their appearance reflects this.

Loss of surface detail could have helped with burrowing. A decrease in size allowed exploitation of new microhabitats.

An enlargement of the head region was probably an adaptation to filter feeding.

trilobiteFossilised

Recent fossils are found in more recent sediments

Gaps in the fossil record

Extinct species

These strata have been disturbed (tilted).

The Earth's landscape has been shaped over a very long time through natural geological processes that continue today. Over time, layers of sedimentary rock, ash, or lava were deposited. Newer layers were deposited on top of older layers so that the oldest layers became buried. Layers are (usually) deposited horizontally and remain so unless they have been disturbed by geological processes such as mountain building or erosion.

Profile with sedimentary rocks containing fossils

More primitive fossils are found in older sediments

geological events). Strata from widespread locations can be correlated because a particular stratum at one location is the same age as the same stratum at a different location. Placing the strata in a sequential (relative) order of past events in a rock profile allows scientists to provide relative dates of past events, but it can not provide an absolute date for an event.

Ground surface

f Some organisms do not fossilise well. The record is biased towards organisms with hard parts.

The formation of rock strata

sedimentsYoungestOldestsediments

The number of extinct species is far greater than the number of species living today.

One of the difficulties with interpreting the fossil record is that it contains gaps. Without a complete record, it can be difficult to establish the evolutionary history of a taxon. There are several reasons for gaps in the fossil record, including:

Fossils in older layers tend to have quite generalised forms. In contrast, organisms alive today have specialised forms.

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The more recent the layer of rock, the more resemblance there is between the fossils found in it and living organisms.

f Organisms are only preserved as fossils rarely and many fossils have not been found.

Key Idea: Fossils provide a record of the appearance and extinction of organisms. The fossil record can be used to establish the relative order of past events Fossils provide a record of the appearance and disappearance of organisms over time. Rock layers (strata) are arranged in the order of deposition (unless they have been disturbed by

In the strata at the end of one geological period, it is common to find many new fossils that become dominant in the next. Each geological period had a different environment from the others. Their boundaries coincided with drastic environmental changes and the appearance of new niches. These produced new selection pressures resulting in new adaptive features in the surviving species, as they responded to the changes.

Interpreting the Fossil Record

New fossil types mark changes in environment

f Fossils are often destroyed or distorted through changes in the preservation environment.

1. Discuss the importance of fossils as a record of evolutionary change over time:

Rock strata are arranged in the order that they were deposited (unless they have been disturbed by geological events). The most recent layers are near the surface and the oldest are at the bottom. Fossils can be used to establish the sequential (relative) order of past events in a rock profile. Each rock layer (stratum) is unique in terms of the type of rock (sedimentary or volcanic) and the type of fossils it contains.

Rock strata are layered through time

These strata remain in their original horizontal position.

Fossil types differ in each stratum Fossils found in a given layer of sedimentary rock are generally significantly different to fossils in other layers.

2. Why can gaps in the fossil record make it difficult to determine the sequence of evolutionary events?

6. (a) State which layers present at location 1 are missing at location 2:

of 67 km separates these rock formations

yearsAdistance

A B C D E F G H I K ML N O J

(a) The youngest rocks at location 1:

5 The rocks in layer H and O are sedimentary rocks. Explain why there are no visible fossils in these layers:

(e) Layer L:

(f) Layer O:

The questions below relate to the diagram above, showing a hypothetical rock profile from two locations separated by a distance of 67 km. There are some differences between the rock layers at the two locations. Apart from layers D and L which are volcanic ash deposits, all other layers comprise sedimentary rock.

(d) Layer G:

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(d) The oldest rocks at location 2:

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Rock profile at location 1

Trilobite fossil Dated at 375 million

4. (a) State which layer at location 1 is of the same age as layer M at location 2:

7. Using radiometric dating, the trilobite fossil was determined to be approximately 375 million years old. The volcanic rock layer (D) was dated at 270 million years old, while rock layer B was dated at 80 million years old. Give the approximate age range (i.e. greater than, less than, or between given dates) of the rock layers listed below:

(b) Explain the reason for your answer above:

(b) Layer C:

Fossils are embedded in the different layers of sedimentary rock

(b) State which layers present at location 2 are missing at location 1:

(b) The oldest rocks at location 1:

Rock profile at location 2

3. Assuming there has been no geologic activity (e.g. tilting or folding), state in which rock layer (A-O) you would find:

(a) Layer A:

1. (a) What is a transitional fossil?

fossils include horses, whales, and Archaeopteryx and other non-avian feathered dinosaurs (below). Archaeopteryx was a transitional form between non-avian dinosaurs and birds. Archaeopteryx was crow-sized (50 cm length) and lived about 150 million years ago. It is regarded as the first primitive bird and had a number of birdlike (avian) features, including feathers. However, it also had many non-avian features, which it shared with theropod dinosaurs of the time.

Avian features

Lacks the reductions and fusions present in other Breastbonebirds is small and lacks a keel

True teeth set in sockets in the jaws

(b) Why are transitional fossils important in understanding evolution?

Transitional fossils are fossils with a mixture of features found in two different, but related, groups. Transitional fossils provide important links in the fossil record and provide evidence to support how one group may have given rise to the other by evolutionary processes. Important examples of transitional

The hind-limb girdle is typical of dinosaurs, although modified

Long, bony tail, shared with other dinosaurs of the time

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Suggested reconstructionbasedon

Key Idea: Transitional fossils show intermediate states between two different, but related, groups. They provide important links in the fossil record

Vertebrae are almost Impressionsflat-faced of feathers attached to the forelimb

Forelimb has three functional fingers with grasping claws

Non-avian features

Belly Incompleteribs

Transitional

fusion of the lower leg attachedImpressionsbonesoffeatherstothetail

of horse phylogeny. It is a complex tree-like lineage with many divergences (below), and a diverse array of often coexisting species. The environmental transition from forest to grasslands drove many of the changes observed in the fossil record. These include reduction in toe number, increased size of cheek teeth, and increasing body size.

The equids also became taller and faster to enable them to view and escape their predators. This is evident in their overall increase in size and the elongation of their limbs. The reduction in the number of toes from four to one (left) also enabled them to run faster and more efficiently.

DentineCementEnamel

1. How did the environmental change, from forest to grassland, influence the following aspects of equid evolution:

The majority of equid evolution took place in North America, although now extinct species did migrate to other areas of the globe at various times. During the late Pliocene (2.6 mya) Equus spread into the Old World and diversified into several species including the modern zebra of Africa and the true horse, Equus caballus. The horse became extinct in the Americas about 11,000 years ago, and was reintroduced in the 16th century by Spanish explorers.

(b) Limb length:

(a) Change in tooth structure:

Hyracotherium(Eohippus)

Hyracotherium molar Equus molar

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Key Idea: The evolution of the horse is one of the most robust examples of evolution documented in the fossil record. The evolution of the horse from the ancestral Hyracotherium to modern Equus is well documented in the fossil record. The rich fossil record, which includes numerous transitional fossils, has enabled scientists to develop a robust model

The cooler climates that prevailed in the Miocene (23 -5 mya) brought about a reduction in forested areas with grasslands becoming more abundant. The change in vegetation resulted in the equids developing more durable teeth to cope with the harsher diet. Over time the equid molar became longer and squarer with a hard cement-like covering to enable them to grind the grasses which became their primary diet.

MesohippusMerychippusEquus

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2. Why does the equid fossil record provide a good example of the evolutionary process?

1.6 m 1.25 m 0.6 m 0.4 m 0510152025303540455055yofMillionsearsago

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limbs became detached from spine

50 mya Pakicetus

The Evolution of Whales

Pakicetus was a transitional species between carnivorous land mammals and the earliest true whales. It was mainly land dwelling, but foraged for food in water. It had four, long limbs. Its eyes were near the top of the head and its nostrils were at the end of the snout. It had external ears, but they showed features of both terrestrial mammals and fully aquatic mammals.

Redrawn from de Muizon Nature 2001 413 pp259-260

Modern whales are categorised into two broad suborders based on the presence or absence of teeth.

provide a good

Legs became shorter

Toothed whales: These have full sets of teeth throughout their lives. Examples: sperm whale and orca.

Baleen whales: Toothless whales, which have a comb-like structure (baleen) in the jaw. Baleen is composed of the protein keratin and is used to filter food from the water. Examples: blue whale, humpback whale.

1. Why does the whale fossil record example of the evolutionary process?

The hind limbs became fully internal and vestigial. Studies of modern whales show that limb development begins, but is arrested at the limb bud stage. The nostrils became modified as blowholes. This recent ancestor to modern whales diverged into two groups (toothed and baleen) about 36 million years ago. Baleen whales have teeth in their early fetal stage, but lose them before birth.

Hind limbs are internal and vestigial (have lost their original function).

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Key Idea: The evolution of whales is well documented in the fossil record, with many transitional forms recording the shift from a terrestrial to an aquatic life. The evolution of modern whales from an ancestral land mammal is well documented in the fossil record. The fossil

Hind

2. Briefly describe the adaptations of whales for swimming that evolved over time:

Humpback whale

record of whales includes many transitional forms, which has enabled scientists to develop an excellent model of whale evolution. The evolution of the whales (below) shows a gradual accumulation of adaptive features that have equipped them for life in the open ocean.

Orca

NOAAPittmanRobert

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Rhodocetus was mainly aquatic (water living). It had adaptations for swimming, including shorter legs and a shorter tail. Its eyes had moved to the side of the skull, and the nostrils were located further up the skull. The ear showed specialisations for hearing in water.

Balaena (recent whale ancestor)

40 mya Dorudon

45 mya Rhodocetus

Dorudon was fully aquatic. Its adaptations for swimming included a long, streamlined body, a broad powerful muscular tail, the development of flippers and webbing. It had very small hind limbs (not attached to the spine) which would no longer bear weight on land.

1. The Galápagos and the Cape Verde Islands are both tropical islands close to the equator, yet their biotas are quite different. Explain why this is the case:

AmerSouthica Africa

Universal origin

Biologists did not fully appreciate the uniqueness and diversity of tropical island biota until explorers began to bring back samples of flora and fauna from their expeditions in the 19th century. The Galápagos Islands, the oldest of which arose 3-4 million years ago, had species similar to but distinct from those on the South American mainland. Similarly, in the Cape Verde Islands, species had close relatives on the West Africa mainland. This suggested to biologists that ancestral forms found their way from the mainland to the islands where they then underwent evolutionary changes.

3. Using an example, describe how biogeography provides support for evolutionary mechanisms:

Tristan da Cunha species

19 Flowering plants

2 Flowering plants 2 Ferns 5 Liverworts 7 Flowering plants

Biogeographical Evidence

Cape Verde Is Atlantic Ocean 450 km 4500 km 3000 km

Galápagos and Cape Verde islands

The island of Tristan da Cunha in the South Atlantic Ocean is a great distance from any other land mass. Even though it is closer to Africa, there are more species closely related to South American species found there (see table on right). This is probably due to the predominant westerly trade winds from the direction of South America. The flowering plants of universal origin are found in both Africa and South America and could have been introduced from either land mass.

Tristan da Cunha

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of species. As described in this activity, island biogeography demonstrates that species on a given island may more closely resemble species on a nearby mainland, rather than species on a distant island with a similar environment.

SouthOceanAtlantic

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305FernsLiverworts

2. Explain why the majority of the plant species found on Tristan da Cunha originated from South America, despite its greater distance from the island:

South American origin

Key Idea: Biogeography provides evidence for how the evolution of species is influenced by isolation, continental influences, geological processes, and dispersal ability. Biogeography is the study of the geographical distribution

African origin

Galapagos Is Paci c Ocean 900 km Wester n Africa

Tristan da Cunha

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AmerSouthica

Mauritius, Farquhar, and Diego Rodriguez. These were almost completely exterminated by early Western sailors, although a small population remains on the island of Aldabra. Another feature of oceanic islands is the adaptive radiation of colonising species into different specialist forms. The three species of Galápagos iguana almost certainly arose,

Crustaceans: Larval stages drift to islands. Crabs often evolve novel forms on islands. Many are restricted to shoreline areas. Some crabs, such as coconut crabs, have adapted to an island niche.

Deep ocean

Land mammals: Few non-flying mammals colonise islands, unless these are very close to the mainland. Mammals have a higher metabolism, need more food and water than reptiles, and cannot sustain themselves on long sea journeys.

through speciation, from a hardy traveller from the South American mainland. The marine iguana (above) feeds on shoreline seaweeds and is an adept swimmer. The two species of land iguana (not pictured) feed on cacti, which are numerous. One of these (the pink iguana) was identified as a separate species only in 2009.

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Oceanic islands have a unique biota because only certain groups of plants and animals tend to colonise them. The animals that successfully colonise oceanic islands have to

Plants: Plants have limited capacity to reach distant islands. Only some have fruits and seeds that are salt tolerant. Many plants are transported to islands by wind or birds.

Blown by strongcrustaceanPlanktonicwinds

Key Idea: The biodiversity of oceanic islands often depends on the distance to the mainland and the ability of plants and animals to survive dispersal.

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The flightless cormorant (above) is one of a number of bird species that lost the power of flight after becoming an island resident. Giant tortoises, such as the 11 subspecies remaining on the Galápagos today (centre) were, until relatively recently, characteristic of many islands in the Indian Ocean including the Seychelles archipelago, Reunion,

Sea mammals: Seals and sea lions have little difficulty in reaching islands, but they return to the sea after the breeding season and do not colonise the interior.

Rafting on drifting vegetationOceanic island

1 Describe one feature typical of an oceanic island coloniser and explain its significance:

be marine in habit or able to survive long periods at sea or in the air. Plants also have limited capacity to reach distant islands. Only some have seeds and fruit that are salt water tolerant. Many plants are transferred to the islands by wind or migrating birds. The biota of the Galápagos islands provide a good example of the result of such a colonisation event.

SwimminglarvaeActiveflight

Ocean Island Colonisers

Reptiles: Reptiles probably reach distant islands by floating in driftwood or on mats of floating vegetation. A low metabolic rate enables them to survive the long periods without food and water.

Amphibians: Cannot live away from fresh water. They seldom reach offshore islands unless that island is a continental remnant.

Seabirds: Seabirds fly to and from islands with relative ease. They may become adapted to life on land, as the flightless cormorant has done in the Galápagos. Others, like the frigate bird, may treat the island as a stopping place.

Small birds, bats, and insects: These animals are blown to islands by accident. They must adapt to life there or perish.

The Galápagos Islands, off the west coast of Ecuador, consist of 16 main islands and six smaller islands. They are home to 14 species of finches, each of which has evolved from a single species of grassquit, which arrived from Ecuador. A fifteenth species inhabits Cocos Island. After colonising the islands, the grassquits diversified in response to the availability of unexploited feeding niches. This adaptive radiation is most evident in the beaks of the different species, which are adapted for different purposes, including crushing seeds, pecking wood, or probing cactus flowers.

Ground finches, genus Geospiza (left) have crushing type beaks for seed eating.

The five species of tree finches are largely arboreal (tree dwelling). Their sharp beaks are well suited to grasping insects which form the most of their diet. One species has demonstrated tool use in extracting insects.

A 2015 revision based on whole genome sequencing has split the sharp beaked finches still further into three distinct groups and has suggested a reclassification. The diagram below shows the islands on which the birds are found and the age of the islands in millions of years (in brackets).

Santiago Is. (0.8)

Española

ISBN: 978-1-927309-56-8

The Cocos Island finch is the only one of Darwin's finches to be found outside the Galápagos. DNA analysis shows it is related to the warbler finches. The ancestral finch therefore colonised the Galápagos before colonising Cocos Island.

Genovesa (0.3)

Wolf (1.0)

Marchena

Santa(0.7) Cruz (1.1) Floreana (~1.0) Fernandina (0.7) Santa Fé (2.7) AmerSouthica GalápagosPacificIs. Ocean Cocos Is 900 km 800 km finchesgroundCactus T finchesreefinchesgroundOther V egeta r finchian Sha r beap k finchgrounded finchIslandCocos bWar finchesler bicolourTiasis relati(mainland v e)

2. How do we know the finches colonised Cocos Island after colonising the Galápagos Islands?

Pinta (0.8)

Is. (3.2)

Darwin (~0.7)

The cactus ground finches (left) have evolved probing beaks to extract seeds and insects from cacti.

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Three species differ mainly in body size and in the size of their beaks. The other three species have longer beaks and supplement their seed diet with cactus flowers and pulp (the cactus finches) or the eggs and blood of other birds and reptile ticks (the sharp-beaked ground finch).

A relatively recent (2005) revision of the phylogeny of the finches is shown right. It places the sharp beaked finch more distant from the other ground finches with which it was previously grouped (all are currently Geospiza).

The beak of the warbler finch is the thinnest of the Galápagos finches. It uses it to spear insects and probe flowers for nectar. It is also the most widespread species, found throughout the archipelago.

(2.4)

San Cristóbal

On Wolf Island, the sharp beaked ground finch has become a specialist blood feeder. Recent genomic analysis has suggested a classification of this species.

Equator

N Isabela Is (0.5)

3. Is there are pattern to how the islands were colonised by the birds? Explain:

(c) The geomagnetic orientation of old rocks (the way that magnetic crystals are lined up in ancient rock gives an indication of the direction the magnetic pole was at the time the rock was formed).

South America India

AustraliaNew GuineaNewZealandNewCaledonia

Direction of ice sheet movement 350-230 million years ago Key

Lystrosaurus is a primitive therapsid (mammal-like) reptile 1 m long, that was widely distributed throughout the southern continents about 240 million years ago.

(b) The direction of ancient ice sheet movements.

Continental Drift and Evolution132

Geomagnetic pole direction 150 million years ago

4. State what general deduction you can make about the position of the polar regions with respect to land masses:

(a) The location of ancient rocks and periods of mountain folding during different geological ages.

(a) The likely position of the South Pole 350-230 million years ago (as indicated by the movement of the ice sheets).

2. Cut out the southern continents on page 183 and arrange them to recreate the supercontinent of Gondwana. Take care to cut the shapes out close to the coastlines. When arranging them into the space showing the outline of Gondwana on the following page, take into account the following information:

Madagascar Africa

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Key Idea: Fossils of related organisms found on separated continents can be explained by continental drift. Continental drift (the movement of the Earth's continents relative to each other) is a measurable phenomenon; it has happened in the past and continues today. Movements of up to 2-11 cm a year have been recorded between continents using laser technology. The movements of the Earth’s 12

North America Asia

3. Once you have positioned the modern continents into the pattern of the supercontinent, mark on the diagram:

Greenland Europe

1. Name the modern landmasses (continents and large islands) that made up the supercontinent of Gondwana:

Distribution of Glossopter is Distribution of Lystrosaur us

This diagram shows some of the data collected that are used as evidence to indicate how the modern continents once fitted together.

(d) The distribution of fossils of ancient species such as Lystrosaurus and Glossopteris

(b) The likely position of the geomagnetic South Pole 150 million years ago (as indicated by ancient geomagnetism).

Precambr ian basement rocks (650-570 mya)

major crustal plates are driven by a geological process known as plate tectonics. Some continents are drifting apart while others are moving together. Many lines of evidence show that the modern continents were once joined together as ‘supercontinents’. One supercontinent, Gondwana, was made up of the southern continents some 200 mya.

Ear ly Palaeozoic folding (570350 mya)

Antarctica

Glossopteris is a hardy plant that grew adjacent to the glacial ice sheets of Gondwana some 350-230 million years ago

Old Precambrian rocks (older than 650 mya)

Late Mesozoic folding (16070 mya)

Late PalaeozoicEarly Mesozoic folding (350-160 mya)

(b) Use a coloured pen to indicate the distribution of Nothofagus on the current world map (on the previous page) and on your completed map of Gondwana above.

7. The Atlantic Ocean is currently opening up at the rate of 2 cm per year. At this rate in the past, calculate how long it would have taken to reach its current extent, with the distance from Africa to South America being 2300 km (assume the rate of spreading has been constant):

6. The southern beech (Nothofagus) is found only in the southern hemisphere, in such places as New Caledonia, New Guinea, eastern Australia (including Tasmania), New Zealand, and southern South America. Fossils of southern beech trees have also been found in Antarctica. They have never been distributed in South Africa or India. The seeds of the southern beech trees are not readily dispersed by the wind and are rapidly killed by exposure to salt water.

(a) Suggest a reason why Nothofagus is not found in Africa or India:

8. Explain how continental drift provides evidence to support evolutionary mechanisms:Gondwana

supercontinent coastline about 250-150 million years ago

5. Fossils of Lystrosaurus are known from Antarctica, South Africa, India and Western China. With the modern continents in their present position, Lystrosaurus could have walked across dry land to get to China, Africa and India. It was not possible for it to walk to Antarctica, however. Explain the distribution of this ancient species in terms of continental drift:

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Cut out the continental land masses that make up the supercontinent of Gondwana and stick them into the space on the previous page

This page has been deliberately left blank

184

LINK 138 WEB 133

Bat

Hind

1. Colour code the bones of the generalised pentadactyl limb (above, left) to identify each group of bones. Using the same colour key, colour the comparative bones of the specialised forelimbs (above, right).

Key Idea: Homologous structures (homologies) are structural similarities present as a result of common ancestry. The common structural components have been adapted to different purposes in different taxa

frontDogleg

Highly modified for flight. Forelimb is shaped for aerodynamic lift and feather attachment.

The bones of the forelimb of air-breathing vertebrates are composed of similar bones arranged in a comparable pattern. This is indicative of common ancestry. The early

133

(b) Human arm:

Forelimb limb wing arm wing

(a) Bird wing:

(d) Dog front leg:

TibiFiFemur(thigh)bulaTarsals(ankle)Metatarsals(sole)Phalanges(toes)aMetacarCar(upperHumerusarm)Radiuspals(wrist)pals(palm)Phalanges(fingers)Ulna Bird

3. Explain how homology in the pentadactyl limb is evidence for adaptive radiation:

forelimbMole flipperSeal Human

Specialisations of pentadactyl limbs

Generalised pentadactyl limb

land vertebrates were amphibians with a pentadactyl limb structure (a limb with five fingers or toes). All vertebrates that descended from these early amphibians have limbs with this same basic pentadactyl pattern. They also illustrate the phenomenon known as adaptive radiation, since the basic limb plan has been adapted to meet the requirements of different niches.

2. Briefly describe the purpose of the major anatomical change that has taken place in each of the limb examples above:

(e) Mole forelimb:

(f) Bat wing:

Homologous Structures

The forelimbs and hind limbs have the same arrangement of bones but they have different names. In many cases bones in different parts of the limb have been highly modified to give it a specialised locomotory function.

Vestigial organs are common in nature. The vestigial hind limbs of modern whales (right) provide anatomical evidence for their evolution from a carnivorous, four footed, terrestrial ancestor. The oldest known whale, Pakicetus, from the early Eocene (~54 mya) still had four limbs. By the late Eocene (~40 mya), whales were fully marine and had lost almost all traces of their former terrestrial life.

Vestigial structures are anatomical features that have been retained through a species' evolution but have lost their ancestral function. Having no obvious function, vestigial structures are no longer subject to natural selection and

134 LINK 129 WEB 134

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Pelvis

hindVestigiallimb

Ancestors of modern whales

Vestigial Structures

Protocetus (mid Eocene). Much more whale-like than Pakicetus. The hind limbs were greatly reduced and although they still protruded from the body (arrowed), they were useless for swimming.

Modern right whale up to 20 mForelimb

Key Idea: The persistence of vestigial structures provides evidence for common ancestry.

Vestigial organs in birds and reptiles

RM-DoC

remain unchanged through a lineage. Their presence can be used to detect common ancestry. Vestigial structures are often homologous to organs that still have a function in other species. For example, the human tail bone (coccyx) has lost its original function (balance and mobility) and is homologous to the fully functioning tail in many other primates.

186 1.8 m long 2.5 m long 20-25 m long

3. Whale evolution shows the presence of transitional forms (fossils that are intermediate between modern forms and very early ancestors). Suggest how vestigial structures indicate the common ancestry of these forms:

2. Suggest why a vestigial structure, once it has been reduced to a certain size, may not disappear altogether:

1. In terms of natural selection explain how structures, that were once useful to an organism, could become vestigial:

In all snakes (far left), one lobe of the lung is vestigial (there is not sufficient room in the narrow body cavity for it). In some snakes there are also vestiges of the pelvic girdle and hind limbs of their walking Likeancestors.allratites, kiwis (left) are flightless. However, more than in other ratites, the wings of kiwis are reduced to tiny vestiges. Kiwis evolved in the absence of predators to a totally ground dwelling existence.

Pakicetus (early Eocene). A carnivorous, four limbed, early Eocene whale ancestor. It was still partly terrestrial and not fully adapted for aquatic life.

Basilosaurus (late Eocene). A very large ancestor of modern whales. The hind limbs contained all the leg bones, but were vestigial and located entirely within the main body, leaving a tissue flap on the surface (arrowed).

Femur

Increasing difference in amino acid sequence Primates Non-mammalian vertebratesPlacental mammals Marsupial Frog 67 Horse 25 Mouse 27 KangarooChicken38 45Human chimpanzee– 0 Rhesus monkey 8Dog 15 Gibbon 2 Gorilla 1 LINK 136 LINK 137 WEB 135

As genetic relatedness decreases, the number of amino acid differences between the haemoglobin beta chains of different vertebrates increases (above). For example, there are no amino acid differences between humans and chimpanzees, indicating they recently shared a common ancestor. Humans and frogs have 67 amino acid differences, indicating they had a common ancestor a very long time ago.

135

f The Pax-6 gene belongs to a family of master genes that regulate the formation of a number of organs, including the eye, during embryonic development.

f Scientists know the role of Pax-6 in eye development because they created a knockout model in mice where the Pax-6 gene is not expressed. The knockout model is eyeless or has very underdeveloped eyes.

The Pax-6 protein provides evidence for evolution

Some proteins are common in many different species. These proteins are called highly conserved proteins, meaning they change (mutate) very little over time. This is because they have critical roles in the organism (e.g. in cellular respiration) and mutations are likely to be lethal.

Key Idea: Proteins are the product of gene expression, so an analysis of the differences between the same protein in different taxa gives an indication of species relatedness. Traditionally, phylogenies were based largely on anatomical traits, and biologists attempted to determine the relationships between taxa based on similarity or by tracing the appearance of key characteristics. With the advent of new molecular techniques, homologies (similarities arising from shared

proteinHistone DNA Emw

Haemoglobin is the oxygen-transporting blood protein found in most vertebrates. The beta chain haemoglobin sequences from different organisms can be compared to determine evolutionary relationships.

f The Pax-6 gene is so highly conserved that the gene from one species can be inserted into another species, and still produce a normal eye.

f This suggests the Pax-6 proteins are homologous, and the gene has been inherited from a common ancestor.

An experiment inserted mouse Pax-6 gene into fly DNA and turned it on in a fly's legs. The fly developed morphologically normal eyes on its legs!

f The Pax-6 gene produces the Pax-6 protein, which acts as a transcription factor to control the expression of other genes.

Haemoglobin homology

ancestry) could be studied at the molecular level as well and the results compared to phylogenies established using other methods. Protein sequencing provides an excellent tool for establishing homologies. A protein has a specific number of amino acids arranged in a specific order. Any differences in the sequence reflect changes in the DNA sequence. Commonly studied proteins include blood proteins, such as haemoglobin, and the respiratory protein cytochrome c.

Evidence indicates that highly conserved proteins are homologous and have been derived from a common ancestor. Because they are highly conserved, changes in the amino acid sequence are likely to represent major divergences between groups during the course of evolution.

Cytochrome C (left) is a respiratory protein located in the electron transport chain in mitochondria.

Histones (right) are a family of proteins that associate with DNA and organise it so that it can fit inside the cell nucleus.

Highly conserved proteins

Homologous Proteins

(b) What type of proteins tend to be highly conserved?

GorillaHuman Baboon Lemur Rat

(d) Why are highly conserved proteins good for constructing phylogenies?

The relationships among tree frogs have been established by immunological studies based on blood proteins such as immunoglobulins and albumins. The immunological distance is a measure of the number of amino acid substitutions between two groups. This, in turn, has been calibrated to provide a time scale showing when the various related groups diverged.

010 60 2030

CrickettreeEuropeantreeAmericanNorthfrogsfrogsfrogChorusfrogsAustraliantreefrog

(b) What evidence is there that the Pax-6 protein is highly conserved?

1. Compare the differences in the haemoglobin sequence of humans, rhesus monkeys, and horses. What do these tell you about the relative relatedness of these organisms?

3. (a) Describe the role of the Pax-6 gene:

01020304050

Millions of years ago

The immune system of one species will recognise the blood proteins of another species as foreign and form antibodies against them. This property can be used to determine the extent of relatedness between species. Blood proteins, such as albumins, are used to prepare antiserum in rabbits, a distantly related species. The antiserum contains antibodies against the test blood proteins (e.g. human) and will react to those proteins in any blood sample they are mixed with. The extent of the reaction indicates how similar the proteins are; the greater the reaction, the more similar the proteins. This principle is illustrated (right) for antiserum produced to human blood and its reaction with the blood of other primates and a rat.

Decreasing recognition of the antibodies against human blood proteins

2. (a) What is a highly conserved protein?

formsPrecipitate

Immunological distance

Using immunology to determine phylogeny

Neurospora crassa (mold)

1. Describe a limitation of using molecular clocks to establish phylogeny:

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(A)(B) LINK 137 WEB 136

In a theoretical example, the DNA sequence for a gene in two species (A & B, right) alive today differs by four bases. The mutation rate for the gene is approximately one base per 25 million years. Based on this rate, it can be determined that the common ancestor for these two species lived 50 mya.

+ 25 million years mutation 1 occurred

homology of cytochrome c (right), a respiratory protein, has been used to construct a phylogenetic tree for some species. Overall, the phylogeny aligns well to other evolutionary data, although the tree indicates that primates branched off before the marsupials diverged from other placental mammals, which is incorrect based on other evidence. Highly conserved proteins, such as cytochrome c, change very little over time and between species because they carry out important roles and if they changed too much they may no longer function properly.

2. For cytochrome c, suggest why amino acids 14 and 17 are unchanged in all the organisms shown in the table:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Human Gly Asp Val Glu Lys Gly Lys Lys Ile Phe Ile Met Lys Cys Ser Gln Cys His Thr Val Glu Lys Pig Val Gln Ala Chicken Ile Val Val Gln Ala Dogfish Val Val Gln Ala Asn Drosophila << Leu Val Gln Arg Ala Ala Wheat << Asn Pro Asp Ala Ala Lys Thr Arg Ala Asp Ala Yeast << Ser Ala Lys Ala Thr Leu Lys Thr Arg Glu Leu Average

Samia cynthis (moth)

The Molecular Clock Hypothesis

Time 0 + 50 million years mutation 2 occurred

Saccharomyces (baker’s yeast) Candida krusei (yeast)

CAATTG CAATTTATCATCG CAATTTATTT CAATCGATCG

organismAncestralThesequence

Cytochrome c and the molecular clock theory amino

CAATTTATCGCommonancestor

This table shows the N-terminal 22 amino acid residues of human cytochrome c, with corresponding sequences from other organisms aligned beneath. Sequences are aligned to give the most position matches. A shaded square indicates no change. In every case, the cytochrome's heme group is attached to the Cys-14 and Cys-17. In Drosophila wheat, and yeast, arrows indicate that several amino acids precede the sequence shown.

species last shared a common ancestor and can be used to construct a phylogenetic tree. The molecular clock for each species, and each protein, may run at different rates, so molecular clock data is calibrated with other evidence (e.g. morphological) to confirm phylogeny. Molecular clock calculations are carried out on DNA or amino acid sequences.

acid substitutions 30 25 20 15 10 50 ScreTRattlesnakTuChiDuPigeonRabbiKangarooPiDonHorseDogMonHumankeykeygtckckenrtleeunawworm fly

Key Idea: The molecular clock hypothesis proposes that mutations occur at a steady rate and that changes in DNA sequences between species can determine phylogeny. The molecular clock hypothesis states that mutations occur at a relatively constant rate for any given gene. The genetic difference between any two species can indicate when two

4. The graph below shows the results of a DNA hybridisation between humans and other primates.

2. The mixture is heated so the DNA separates. The DNA from the two species is mixed together.

DNA to that of other primates 0 20 40 60 80 100

These

(a) Which primate is most closely related to humans?

1. How can DNA hybridisation give a measure of genetic relatedness between species?

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DNAHybrid

DNA hybridisation technique

the DNA is the same and cannot provide specific information about what the similarities or differences are. Although it has largely been replaced by DNA sequence analysis, DNA hybridisation is still used in microbial studies and has been used to determine the date of human divergence from apes, which has been estimated at 10 and 5 million years ago.

Homologous DNA Sequences

bases do not matchbases match

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DNA Chimpanzee

Fragments of double stranded DNA held together by hydrogen bonds.

3. What is responsible for the hybridisation between the DNA strands?

84.2%90.5%91.1%94.7%97.6%100% 58.0% speciesPrimate Human DNA similarity (%) CapuchinGalago monkey Vervet SimilarityChimpanzeeGibbonRhesusmonkeymonkeyofhuman

5. Hybrid DNA from species A and B comes apart at a lower temperature that of species A and C. Which species is A most closely related to?

3. As it cools, bonds form between compatible nucleotides. Hybrid double-stranded DNA forms.

190

Human DNA

1. DNA from the two species to be compared is extracted, purified and cut into short fragments.

(b) Which primate is most distantly related to humans?

4. If species share low similarity, the hybrid DNA will have few bonds (and the strands will be weakly held together). The number of bonds (and therefore the strength of the hybrid DNA) increases with increasing similarity.

separate.Single-strandedDNAfromthetwospeciesismixedThese

Key Idea: DNA hybridisation compares DNA similarity between species and can be used to measure relatedness. DNA hybridisation is a technique used to quantify the DNA similarity between species. More closely related species have fewer genetic differences than more distantly related species. The method provides information only about how much of

Cool samplesthe

5. The similarity is measured by heating the hybrid DNA to force it to form single strands. The greater the similarity, the more heat that is required to break the hybrid DNA apart.

Heat the DNA samples. Heat disrupts the hydrogen bonding so the strands

2. Why do the double strands of DNA break when they are heated?

Increasedfactorexpression bone growth regulator elongates digits.

22 23 Rhesus

During development, vertebrate embryos pass through the same stages, in the same sequence, regardless of the total time period of development. This similarity is strong evidence of their shared ancestry. The stage of embryonic development is identified using a standardised system based on the development of structures, not by size or the number of days of development. The Carnegie stages (right) cover the first 60 days of development. 10 11 12 13 14

the appearance of a growing embryo. Today, developmental biology focuses on the genetic control of development and its role in producing the large differences we see in the adult appearance of different species. Differences in gene expression during development are behind these differences.

Carnegie stage of embryonic development 18 19 20 21 monkey Mouse Chicken Human Stage 14 Limb buds Stage 17 Digits form Stage 23 Digits separate

2. Explain how different specialised limb structures can arise from a basic pentadactyl structure:

Bat wings are highly specialised structures with unique features, such as elongated wrist and fingers (I-V) and membranous wing surfaces. The forelimb structures of bats and mice are homologous, but how the limb looks and works is quite different.

I IIIII IV V III IIIIV V

Apoptosis suppressed by expression of an inhibitory growth

Developmental Evidence for Evolution138 LINK 133 WEB 138

of a

Developmental biology

Like humans, mice have digits that become fully separated by interdigital apoptosis during development. In bat forelimbs, this controlled destruction of the tissue between the forelimb digits is inhibited. The developmental program is the result of different patterns of expression of the same genes in the two types of embryos.

1. Describe a feature of vertebrate embryonic development that supports evolution from a common ancestor:

Key Idea: Similarities in the development of embryos, including the genetic control of that development, provides strong evidence for evolution. Developmental biology studies the processes by which organisms grow and develop. In the past, it was restricted to

Limb homology and the control of development

102030405060Days 0

15 16

As we have seen, homology (e.g. in limb structure) is evidence of shared ancestry. How do these homologous structures become so different in appearance? The answer lies in the way the same genes are regulated during development.

All vertebrate limbs form as buds at the same stage of development. At first, the limbs resemble paddles, but apoptosis (programmed cell death) of the tissue between the developing bones separates the digits to form fingers and toes.

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2. Outline how studying the duplication of genes evidence for evolution: genes and arthropods

By looking at the DNA sequences in a series of genes we can piece together the order in which genes were duplicated and modified. The sequence above shows the order in which genes that are expressed in various parts of an arthropod appeared, starting with the original antennapedia (Antp) gene, which controls the development of appendages near the head.

We can identify which body segments the genes are expressed in and so work out the order in which body segments were modified. Above we start with a primitive arthropod (A). Three genes control development of the head, the middle segments, and the tail. Subsequent duplication and modification of genes produces an arthropod resembling a centipede (B), then a primitive wingless insect (C), and finally a modern winged insect (D).

192

Evolution: you work with what you've got!

Developmental

(4) Modularity: Modular architecture in animals (e.g. arthropods) enables modification and specialisation of individual body parts. Genetic switches allow changes in one part of a structure, independent of other parts. Segmental modifications produce a large amount of variation in arthropods.

139 WEB 139 LINK 80 LINK 138

structure, i.e. the body is made up of repeating units. These are more obvious in taxa where the repeating 'modules' have been less modified, e.g. centipedes. In arthropods, modification of individual segments through duplication and modification of genes has seen the evolution of insects, arachnids, and crustaceans. For example, a gene involved in the development of appendages in arthropods can be duplicated and the duplicate gene modified. This produces a set of modifications to some appendages, enabling a new set of functions without having to modify all other the appendages (below).

Head (other mouthparts)

Myriopods Insects Arachnids Crustaceans

Antp

Thoracic AbdomenWingsAbdomenlegsend

BDCA

1. Describe how modularity the evolution of complex features:

Four principles underlie the role of developmental genes in the evolution of novel forms:

allows

Ubx abd-AScrScrScr abd

Key Idea: The varied appendages of arthropods (and some other animals) can be linked to the duplication and modification of genes and their expression. Evolutionary developmental biology (or evo-devo) is a relatively new area in evolutionary biology that examines how modifications in developmental processes can lead to novel features. Even very small changes (mutations) in the genes controlling development can have a profound effect on morphology, and have been important in the evolution of novel structures and body plans. Arthropods, as well as annelids and vertebrates, have a highly modular body

AntpAntpAntp

Evolution of Novel Forms

(1) Evolution works with what is already present: New structures are modifications of pre-existing structures.

(2) Multifunctionality and (3) redundancy: Functional redundancy in any part of a multifunctional structure allows for specialisation and division of labour through the development of two separate structures. Example: the diversity of appendages (including mouthparts) in arthropods.

Head (mandible/maxillae)

provides

Homologous proteins and DNA sequences

HINT: Include reference to relative dating and past environments.

HINT: What do homology and vestigial structures tell us about common ancestry?

Interpreting the fossil record

Biogeographical evidence

Homologous structures

HINT: Include reference to island biogeography and continental drift.

HINT: How can sequence homology help determine phylogeny?

141

Rod-like bones that help pump water over gills are present, but the presence of ribs indicates that lungs were also present.

1. Use the information above to place Tiktaalik on the time line of vertebrate evolution. Discuss the evidence for your decision.

Fish-like fins are clearly visible.

Vertebrate ancestor 550 mya 400 mya 365 mya 300 mya Jawless fish Bony fish Amphibians Reptiles Birds Mammals 150 mya Ghedoghedo

The fossil of Tiktaalik was covered with scales much like those of fish.

The bones of the limbs have a primitive pentadactyl arrangement, similar to tetrapods, which allowed it to support its body weight.

Tiktaalik's head is flattened horizontally like that of a crocodile with the eyes on top, looking up.

In 2004, a fossil of an unknown vertebrate was discovered in northern Canada and subsequently called Tiktaalik roseae. The Tiktaalik fossil was quite well preserved and many interesting features could be identified. These are shown on the photograph of the fossil below.

NCEA Style Question: Evidence for Evolution

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The shoulder bones are not attached to the skull, allowing its neck to turn independently of the body.

C A structure that has lost its ancestral function but has been retained through evolution in a much reduced form.

A The science determining the relative order of past events, without necessarily determining their absolute age.

fossilfossil homologousrecord structure

IbisFlamingocode.ShoebillPelicanStork 01020304050 010 5

New vultureWorld

(a) Place an X next to the last common ancestor of all the birds:

(b) What does the homology of these bones indicate?

i: Storks and vultures:

(f) How long ago did ibises and vultures share a common ancestor?

(d) What is the difference in DNA (score) between:

by matching each term to its definition, as identified by its preceding letter

Millions of years ago

phylogenetic tree relative 1.vestigialtransitionaldatingfossilstructureTestyourvocabulary

F Structures in different but related species that are derived from the same ancestral structure but now serve different purposes, e.g. wings in birds and fins in whales.

G The evolutionary history or genealogy of a group of organisms represented as a ‘tree’ showing descent of new species from the ancestral one.

Human Bird Whale

D The preserved remains or traces of a past organism.

2. The diagram right shows the evolutionary relationship of a group of birds based on DNA similarities:

DNA difference score

(b) How many years ago did storks diverge from vultures?

3. (a) The diagrams right show the forelimbs of a whale, bird, and human. Shade the diagram to indicate which bones are homologous. Use the same colour to indicate the equivalent bones in each limb.

ii: Ibises and shoebills:

(e) Which of the birds is the least related to vultures?

E The sum total of current paleontological knowledge. It is all the fossils that have existed throughout life’s history, whether they have been found or not.

B The fossilised remains of organisms that illustrate an evolutionary transition. They possess both primitive and derived characteristics.

c Changes in the manipulative ability of the hand.

Achievement criteria for achieved, merit, and excellence

Recognisable trends characterise the evolution of humans: bipedalism, increase in brain size, reduction in teeth, reduction in facial projection, and increasing importance of art, spirituality, tool technology, and sociality.

H.H.H.H.H.H.H.Homoerectusergasterfloresiensishabilisheidelbergensisneanderthalensissapiens

c E Demonstrate comprehensive understanding of trends in human evolution: Link biological ideas about trends in human evolution. This may involve justifying, relating, evaluating, comparing and contrasting, and analysing using scientific evidence.

b The use of fire

Achievement Standard 3.6

Biological evolution ape

primate Paranthropus spp.

f Shelter including caves, temporary settlements and permanent settlements.

Australopithecusramidus spp. bipedal hominoidhominidgracileDmanisiDenisovanscarrying(bipedalism)anglefossils

c 1 Human biological evolution begins with early bipedal hominins and may require comparison with living hominids. These trends involve: 143 157

c M Demonstrate in-depth understanding of trends in human evolution: Use biological ideas to explain how or why trends in human evolution occur.

Au. Ardipithecusafarensis

e Food gathering, including hunter gatherer to domestication of plants and animals.

Key terms

b Changes in skull and endocranial features that reveal changes in brain structure.

Explanatory notes: Trends in human evolution numberActivity Trends in human evolution refer to changes over time in relation to…

a The use of tools (stone, wood, and bone) and changes in tool technology.

a Skeletal changes linked to bipedalism.

hypothesisOuthypothesismultiregionalDispersalWernicke'sPalaeolithicOldowanNeolithicMousterianMesolithicBroca'sAcheuleanCulturalvalgussexualrobustprognathicprehensiledimorphismangleevolution(tool)area(tool)(tool)areaofAfrica

Trends in evolutionhuman

c Clothing

d Abstract thought, including communication, language, and art.

Achievement criteria and explanatory notes

c 3 Patterns of dispersal of hominins. Hominins refers to living and fossil species belonging to the human lineage. 173 179

c A Demonstrate understanding of trends in human evolution: Use biological ideas to describe trends in human evolution.

c 2 Human cultural evolution including: 161 169

c Describe trends in the dexterity and manipulative abilities of the hand from Australopithecus through to early Homo species to Neanderthals and modern humans. Relate these to the emergence and increasing sophistication of tool use.

Activities 161 - 172, 182

c Describe trends in and consequences of brain development, including the beginning of abstract thought and the development of language and of the areas of the brain associated with it.

c Describe trends in the size and shape of the skull, face, and dentition from Australopithecus through to early Homo species to Neanderthals and modern humans. Explain what endocranial features tell us about changes in brain size and organisation.

c Describe the anatomical features associated with bipedalism, including features of the pelvis, the significance of the valgus (carrying) angle, and the position of the foramen magnum.

Humans as primates

The cultural evolution of humans

c Describe primate characteristics as they relate to humans, especially features of the hand and skull.

Activities 147 160, 182

c Describe the features of the Palaeolithic tool cultures (Oldowan, Acheulean, Mousterian), identifying advancements in tool technology at each stage.

c Compare and contrast the main hypotheses for the origin and dispersal of hominins, including evidence. Include reference to the out of Africa and multiregional hypotheses.

What you need to know for this Achievement Standard

c Explain the significance of purpose-made clothing in human cultural evolution. Identify when humans began to make and wear clothing, explain why, and describe the evidence for its origin.

c Describe the selection pressures on early hominins and the benefits of reducing body hair and adopting a bipedal gait as a form of locomotion.

Patterns of hominin dispersal

Activities 173 182

By the end of this section you should be able to:

c Describe and explain how new fossil and genetic evidence is revealing a more complicated picture of human origins and dispersal, including the likely interbreeding between hominin populations and its consequence to modern populations. Include reference to the Dmanisi fossils, Denisovans, Neanderthals, Homo naledi, and/or the Flores finds. Explain the importance of accurate dating to the interpretation of these finds.

The biological evolution of humans

By the end of this section you should be able to:

Activities 142 146

c Describe and explain the increasing importance of art and spirituality in human cultural evolution and relate these trends to other changes occurring at the same time.

By the end of this section you should be able to:

c Explain how the controlled use of fire influenced and benefited human cultural evolution.

c Describe the anatomical and behavioural features that are unique to humans.

c State the full classification of modern humans.

c Describe and explain the change from a hunter-gatherer lifestyle to one involving the domestication of plants and animals. Describe trends in the types of shelter associated with these changes, including reference to caves, and temporary and permanent settlements.

Monkeys walk quadrupedally on the palms of their hands and the soles of their feet. In the trees, they walk along the tops of branches, gripping them with their hands and feet.

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The life span of a primate is generally longer than most other mammals and there is a greater dependency on highly flexible learned behaviour. Primates tend to be highly sociable (above). Unusually for mammals, adult males of many primate species often associate permanently with the group.

The brain is large and generally more complex than in other mammals.

Primates have a generalised dental pattern particularly in the back teeth. Unspecialised teeth enabled primates to adopt a flexible omnivorous diet.

Primate Characteristics143

feet, physiological features include a longer gestation than other mammals, and behavioural features include prolonged infant dependency and keen social behaviour.

Chimpanzees and gorillas spend more time out of trees than do either of the Asian apes. The chimpanzee above shows typical knuckle-walking behaviour. Their relatively long arms facilitate this mode of locomotion.

Key Idea: Primates exhibit unique, but quite generalised, morphological, physiological, and behavioural features. Morphological features include five digits on the hands and

A trend towards a reduced snout and flattened face and reduced olfactory regions in the brain. Baboons go against this trend, with a secondary increase in muzzle length.

General

There is an emphasis on vision, the visual areas of the brain are enhanced. Well developed binocular, stereoscopic vision provides overlapping visual fields and good depth perception. Colour vision is probably present in all primates, except specialised nocturnal forms.

Primates have a tendency toward erectness, particularly in the upper body, as seen in the gorilla, above. This tendency is associated with sitting, standing, leaping, and (in some) walking.

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Gibbons are the smallest of the apes and are specialised to use brachiation (a technique of under-branch swinging), in combination with rapid climbing, midair leaps, and bipedal running, to move quickly through the forest.

The gestation (pregnancy period) in primates is longer than most other mammals. Primates typically have one young per pregnancy (below). Infancy is prolonged with longer periods of infant dependency and a large parental investment in each offspring. This nurturing increases the survival rate of the young and allows cultural development.

Teeth shape and dental arrangement:

2. Humans belong to the order Primates. Describe the features of humans that characterise their primate heritage:

The primate pictured is a white-fronted capuchin monkey (Cebus albifrons) from northern South America. These monkeys inhabit the mid-canopy deciduous, gallery forests.

FaceVision:shape

specialisation:

Limb joints:

Hands and feet:

1. On the diagram of the capuchin below, briefly describe the general physical characteristics of all primates as indicated:

BrainCollarbone:Posture:Reproduction:sizeand

and snout:

Social organisation:

Features possessed to varying degrees by subfamily Homininae:

• Most predominately quadrupedal

Characteristic features of the lesser apes:

• Arboreal; sleep on tree branches and do not build

• Long forearms with hook-like fingers specialised for brachiation

200

Tribe Hominini: Humans, their ancestors, and chimpanzees

Subfamily Ponginae

• No tail

• Partially or habitually bipedal and ground dwelling

Tribe Gorillini: Gorillas

1. Use the information above to complete the phylogeny of Hominoidea:

• Broad chest, pelvis, and shoulders

144

• Complex social behaviour

Subtribe Panina Chimpanzees

Orangutan

Family Hylobatidae

Photocopying Prohibited

• Typical ape-like dentition but teeth large in gorillas and small in humans

Superfamily Hominoidea

• Large cerebral cortex

Hominins

• Larger brain

• Reduced canines

SuperfamilyreducedFamilySubfamilyTribeSubtribe

Hominoids and Hominins

KNOW

Subtribe Australopithecina Australopithecines (extinct)

• Pads on the rump (ischial callosities)

Subfamily Homininae

• All found in Southeast Asia

flattened noses. Hominins (humans and their extinct closest ancestors) are a subtribe within this larger taxon identified by human features including dentition and brain size. The older taxon hominid is now a collective term encompassing the great apes and hominins and no longer refers just to humans.

• Most omnivorous

• Large and sexually dimorphic

Siamang

Hominoid features (lesser apes & hominids)

• Relatively long arms and mobile shoulder joints

Subtribe Hominina Humans & their ancestors

Key Idea: The hominins include modern humans and their extinct ancestors. Hominins are part of a larger superfamily, the hominoids, which also includes the apes. The hominoids (apes as well as humans and their ancestors) are large, tailless primates, with bony eye ridges and

Hominoidea

Characteristic features of the hominids:

• Semi-erect or fully erect posture

2. What are the differences between hominoids and hominins?

Family Hominidae (hominids)

Gibbonnests

• Highly sensitive skin, body hair

Flexible joints in the hand allow it to flex, increasing dexterity.

Chimpanzeesgrip.are very capable tool users, but their dexterity is limited by the length of their hand compared to the thumb and the rigid wrist bones that limit wrist rotation.

The Primate Hand

Key Idea: Primates have grasping hands, but the human hand is particularly developed with respect to dexterity and the manipulation of objects. Primates have a grasping hand. They are able to pick things

up, hold, and manipulate them, although the degree to which a primate can do this depends on the species. Humans have a highly advanced ability to manipulate objects with their hands because the thumb is very long relative to the hand.

New research suggests manipulating objects may not have been the only important factor in the evolution of the human hand. The human hand shape is one of the only configurations possible that maintains dexterity while allowing the hand to form a fist. Although a punch with a closed fist produces the same force as a slap with an open palm, a punch delivers the force to a smaller area, producing a much greater impact and potential for damage to an opponent.

145

powerPrecision/grip

Nails are found on at least some digits in all modern primates.

The fingers have end tactile pads that contain huge numbers of nerve endings, producing a highly sensitive surface.

LINK 143 LINK 153 WEB 145

3. Identify two features that make the human hand so dexterous and compare them to a chimpanzee hand:

Precision grip

Highly mobile thumb, able to touch all other fingers on the hand.

2. Explain why being able to manipulate objects is an evolutionary advantage:

1. Name two possible selective pressures acting on the human hand:

Power grip

Index finger and little finger are able to pivot and move towards each other, allowing the fingers to form around small objects.

Grips of the human hand

LBSphotosAll LBS

Large muscles, especially around the thumb, produce a powerful

146

(f) Large canines:

The skull of the gorilla is not typical of primate skulls in general. It is highly specialised for its niche, which includes processing a low-grade diet of foliage. It is shown here to acquaint you with the terms used in describing the features of primate skulls. The skulls shown on the right are of two apes (a male gorilla and an orangutan), and an Old World monkey (a baboon). The baboon skull is clearly quite different from those of the apes. (b) gorilla skull

LINK 150 LINK 147

Gorilla

(a) Large sagittal crest:

(a) (e) (i) (j)(k) (d) (c) (g) (h) (f)

(g) Heavy brow ridge:

Brow ZygomaticSagittalridgecrestbone (malar) Foramen magnum Nuchal Prognathiccrestmuzzle ZygomaticMandible arch (=cheek bone) CranialMolarsCanine vault

1. Label the gorilla skull above, using the list of anatomical terms in the box above.

Diastema (gap between two teeth)

Key Idea: Identification and comparison of different parts of a primate skull can help to identify the type of primate and various aspects of its biology (e.g. diet).

202

(d) Massive molars:

3. The female skull differs markedly from the male skull in a number of ways. Briefly describe four features that are different between the male skull (above) and the female skull (right) which is shown smaller here: (d)(c)(b)(a)

(b) Nuchal crest:

Photocopying Prohibited

KNOW

Male

(e) Foramen magnum at rear:

Female gorilla skull

Anatomical terms

Primate Skull Features

2. Briefly describe the function or significance of each of the seven features below that are found on gorilla skulls:

you to identify some of the evolutionary ‘landmarks’ in the development of humans. Use this page to compare the features of a modern human skull with the skulls of early humans described later in this topic.

Glabella, frontal bone, zygomatic arch, nasal bones, maxilla, occipital bone, nuchal line, mastoid process, sagittal suture, mandible, temporal line, parietal bone, foramen magnum, malar (zygomatic) bone, occipital protuberance

1. Label the views of a modern human skull using the list of anatomical terms in the blue box below:

LINK 146 LINK 150 WEB 147

Key Idea: An understanding of simple skull anatomy is useful when comparing the skulls of humans and their ancestors. Knowing the names of the major bones, as well as the features associated with a modern human skull, will help

Human Skull Anatomy

2. Describe six features considered to be characteristic of modern human skulls: (f)(e)(d)(c)(b)(a)

Anatomical terms

147

Photocopying Prohibited

204

Trends in Human Evolution: Overview

here. The early australopithecines were almost certainly ancestral to Homo habilis, which was ancestral to modern humans. Some populations of Homo erectus migrated out of Africa, eventually giving rise to populations of Homo in the Middle East and Europe. Neanderthals eventually evolved in Western Europe and modern humans in Africa.

KNOW

148

Key Idea: The hominin fossil record shows clear evolutionary trends towards bipedalism, increased brain size, increased height, and increased technical ability. The diagram below and opposite shows a consensus view of the trends in hominin evolution over time. Only the five species representative of the general trends are shown

DidierDescouensCC4.0 3.9 million2.9 million years ago Mean 110457volumebraincm3cm 130 cm 179 cm Mean552volumebraincm3 Mean1016volumebraincm3 Australopithecus afarensis Australopithecus afarensis Homo habilis Oldowan tools Acheulean tools Homo habilis Homo erectus Homo erectus 2.8 million1.5 million years ago 1.9 million600,000 years ago 1. Describe the general changes in the following trends: (a) Angle of the face: (b) Size of the brain and skull: (c) Height and stance: (d) Skill at tool making: WEB 148 LINK 150 LINK 162 LINK 151

205 © 1988-2016 BIOZONE International ISBN: 978-1-927309-56-8 Photocopying Prohibited DidierDescouensCC4.0 170 cm 183 cm Mean1512volumebraincm3 Mean1335volumebraincm3 Mousterian tools Neolithic tools Homo heidelbergensis (not shown) Homo neanderthalensis Homo neanderthalensis Homo sapiens

are

neanderthalensisHomo became extinct about 30,000 years ago. 500,000 - 40,000 years ago 200,000 years ago - present 2. What was happening to the climate and environment as human ancestors evolved? 3.

FluctuatingCool interglacialsglacial/Open grassland 4 mya 2 mya Present

of Homo neanderthalensis and

sized. Describe

main differences between them: Climate

Homo sapiens

Homo neanderthalensis and Homo sapiens lived at roughly the same time. However H. sapiens evolved in warmer Africa and H. neanderthalensis evolved in cooler Europe. They may have overlapped in space for a few thousand years as H. sapiens migrated out of Africa. The skulls Homo sapiens similarly the and environmental changes

ForestedWarm

of fossil data. The hominin lineage underwent an adaptive radiation about 3 mya, producing many different species. The genus Australopithecus gave rise to the genus Homo and the genus Paranthropus, which coexisted with early Homo, but eventually became extinct about 1 mya. The genus Homo is represented by many species as successive waves migrated out of Africa. Homo sapiens, which migrated out of Africa 80,000-60,000 years ago, is now the only living species.

Human Evolution: Probable Phylogenies

*The species marked with an asterisk (*) were all unknown a decade or so ago (and may be missing from many textbooks on the subject). There are likely to be many as yet ‘undiscovered’ species in the fossil record between 7 and 4 million years ago.

Denisovan hominin dated at > 30,000 (Russia). Species currently not assigned.

rudolfensisHomo

Species in bold are representative of the trends seen in hominin evolution.

WEB 149 LINK 148 LINK 157

Kenyanthropusplatyops*

Finds such as H. georgicus generate debate over the various models of the hominin lineage. H. georgicus is found outside Africa somewhat earlier than expected.

149 012345Time ago)earsyof(millions ramidusramidusArdipithecus* Australopithecus Australopithecusdeyiremeda anamensis * Homo sapiens heidelbergensisnalediHomoHomo Homo erectus ergasterHomo Homo habilis Paranthropusrobustus Australopithecusafricanus Australopithecus afarensis antecessorHomo* bahrelghazaliAustralopithecus* Australopithecusgarhi* * Paranthropusboisei Homo neanderthalensis 76 tchadensisSahelanthropus*Orrorintugenensis* kadabbaramidusArdipithecus* ? ? ? ? ? ? ?? ? ? sapiensHomoidaltu* floresiensisHomo* ? georgicusHomo* ?? Australopithecus Paranthropusaethiopicus sediba*

Homo naledi was discovered in 2013 in Rising Star Cave, South Africa. Becuase the bones where found on the surface it is very difficult to date. It may have lived as long ago as 2.8 million years ago.

Key Idea: Homo sapiens are the last representative of a once extensive, multi-branched hominin evolutionary tree. Distinguishing the human lineage from all these species can be difficult and in some cases open to interpretation. The diagram below shows a possible evolutionary history of hominins, demonstrating the fact that human evolution was not a linear sequence and that many phylogenies are tenable. There is much controversy over the interpretation

Australopithecines

The earliest australopithecines were among the first apes to achieve bipedalism. They possessed a gracile body form and were probably opportunistic omnivores, scavenging meat from carcasses and exploiting a range of resources.

Australopithecus afarensis , Homo habilis, Homo ergaster...

Homo erectus, Homo ergaster, Homo floresiensis

Paranthropines

Paranthropus robustus, Paranthropus boisei

Australopithecus afarensis, Australopithecus africanus, Australopithecus sediba

3. Explain how finds such as Homo naledi and Homo georgicus force us to rethink our understanding of how and where humans evolved:

Group Examples

Archaic and modern humans Homo sapiens, Homo neanderthalensis, Homo heidelbergensis

Essentially chimpanzee-like animals that have begun to show some human characteristics in their locomotion (bipedalism) and in the shape and arrangement of their teeth. Sahelanthropus tchadensis may be a common ancestor of chimpanzees and humans.

4. Which hominin existed for the longest length of time?

This group shows the first signs of brain enlargement, more meat in the diet as well as the first recognisable stone tool culture. The post-cranial (below the head) skeleton remains small and slight, much like that of the australopithecines.

Very early hominids Ardipithecus ramidus, Orrorin tugenensis

1. On the opposite page, colour in the blue outlined species boxes so that all species in the group are coloured the same: archaic and modern humans (orange), erectines (green), habilines (red), paranthropines (yellow), australopithecines (black), and very early hominins (blue).

Habilines Homo habilis

(c)(b)(a)

2. The relationships between ancestral hominins is open to interpretation. The diagram opposite allows for various phylogenies to be constructed as hypotheses because the exact lineages are unknown. Starting at Australopithecus afarensis, complete three likely lineages for the evolution of Homo sapiens by writing the species in order of appearance. You can use the dotted lines to help you but other paths may be possible. The first one has been started for you:

5. Which hominin is the probable most recent ancestor of Homo sapiens?

There have been many recent discoveries of relatively recent Homo species throughout Eastern Europe and Asia. How these fit into the hominin lineage and how they are related to modern humans are still debated. These specimens influence the interpretations of early human migration across the world.

These early hominins represent a group specialised for eating a bulky, low-grade vegetarian diet. They evolved large cheek teeth, powerful chewing muscles and a generally robust skull (large crests for muscle attachment, heavily buttressed face).

Homo erectus and closely related species show increasingly sophisticated tool cultures. H. erectus spread throughout Asia. There is much debate over how the different erectine species are related, with some paleontologists suggesting that all the erectines should be labelled as one species.

Erectines

Brain case: size and shape

Key Idea: The trend in hominin skulls has been towards a greater volume, flatter face, and more gracile features.

1. Face

Degree of prognathism (snout or muzzle)

The skulls show in this activity are representative of the many hominins both modern and prehistoric. The features mentioned below and shown in the diagram below are features that should be noted when looking at trends in skull evolution.

Trends in Skull Anatomy

150

Sagittal crest present? (site of attachment for jaw muscles)

development? Size and shape of zygomatic arch (cheek bones)

Size of mandible (jaw bone)

(b) Rear view: where is skull the widest, low down or high up? Shape: pentagonal, rounded, bell-shaped?

Size of biting front teeth (incisors), canines and molars

208

Chin present?

The shape of the modern human skull is quite different from its ancestors and that of Neanderthals. The human skull has a very high forehead and domed skull, whereas early ancestors had flatter foreheads and more elongated skulls.

FacialBroanglewridge

3. Braincase

Photocopying Prohibited

Shape and slope of forehead

(b) Degree of curvature of dental arcade (tooth row).

(f) Position of foramen magnum (opening at base of skull connected to spine).

1. For each of the hominin species describe the features of the skull. Use the diagram above as a guide. (a) Australopithecus afarensis: (b) Homo habilis: (c) Homo erectus: WEB 150 LINK 146 LINK 147

KNOW

(d) Size of cheek region.

(d) Shape of occipital region (back of skull) when viewed from the side: presence of bun?

(e) Dorsal (top) view: where is the skull widest (rear, middle ear, etc.)?

Position of the foramen magnum (hole at the base of the skull that joins on to the spine)

Nuchal crest present? (site of attachment for neck muscles)

Diastema (gap) between incisors and canines present of absent?

Modern humans have rather gracile skulls compared to their ancestors. The cheek bones and jaw are both smaller and the brow ridges are much reduced relative to earlier hominins. These changes tend to reflect a change in diet to one that requires less chewing (e.g. from tough vegetable matter to a greater amount of (cooked) meat).

(a) Size of the face compared to the braincase.

(b) Degree of prognathism (snout or muzzle development) of the jaw and mid face (mid-face projection).

Skull features

(a) Size and thickness of lower jaw.

ISBN: 978-1-927309-56-8

(a) Shape of forehead (slope, height).

2. Jaws (mandible)

bunOccipital

Homo erectus

f Neanderthals evolved in Southern and Western Europe and are generally thought of as being adapted for the cooler conditions found there. However examination of the nasal cavity finds it does not fit the general rule in mammals that in cold climates there is usually a reduction in the size of the nose and nasal cavities. The Neanderthal nose size is therefore a bit of an oddity and may be linked simply to the degree of facial projection. Also the internal sinuses are small and do follow the rule for cold climates.

magnumofAngle/positionforamen(FM) FM FM FM FM (d) Homo neanderthalensis: (e) Homo sapiens:

f There is also no nuchal ridge as the skull is now balanced directly above the spine so only small muscles are required to hold it upright. There is a prominent chin which acts as a buttress (support) for the small jaw.

Homo sapiens

Homo neanderthalensis

f The skull features a large occipital 'bun' which may reflect an enlarged occipital lobe. The occipital lobe is involved with visual processing. It could also reflect a larger cerebellum, which is involved in the coordination of movement and spatial information.

f The modern human skull sports a high vertical forehead and large domed skull. This reflects an increase in the size of the frontal lobe of the cerebral cortex.

Heavy brow ridge

f There is no brow ridge and the facial and cheek bones have all been reduced in size. The jaw is smaller relative to the skull than in any other hominin, as are the cheek bones and teeth. This may reflect a shift in diet to food that required less chewing (less powerful musculature would be needed so muscle attachments can be less robust).

Homo habilis

afarensisAustralopithecus

Homo sapiens 0.08 1335

560860

(mya)

vo lume (cm3)

2016 research shows that rapid brain expansion in humans was linked to a single substitution mutation about 800,000 years ago. This mutation changed the function of an existing gene and is associated with rapid proliferation of nerve cells in the neocortex. The mutation is unique to humans and is fixed in the human genome (all humans have it).

2. There were two ‘bursts’ (sudden increases) of brain expansion during human evolution. Indicate on the graph you have plotted where you think these two events occurred.

Paranthropus robustus 2.0

210

3(cmvolumebrainEstimated)

Photocopying Prohibited

Mean volume of 1335 cm3 for living humans

Homo habilis 1.8 552

1. Plot the data in the table on the estimated Brain volume for hominin species (above) onto the graph below.

ChimpanzeesHumansAge(years)

Brain volume for hominin species

Graph above right: In most primates, including chimpanzees, brain growth, relative to body size, slows markedly after birth while body growth continues. In human infants, brain growth does not slow until more than a year after birth, which results in larger brain masses for humans than for chimpanzees at any given age (or body weight).

Trends Brain Volume 0 Millions of years ago

LINK 148 LINK 167

Homo ergaster

Table above: Summary of the changes in estimated brain volume recorded from fossil hominins. The dates for each species are generally the middle of their time range for long-lived species or at the beginning of their time range for short-lived species.

Key Idea: The evolution of a large brain was crucial to our development of language, technology, and culture. The human brain is responsible for our unique behavioural qualities. It makes up just 2% of our body weight, but demands about 20% of the body’s energy at rest. This makes the brain an expensive organ to maintain. The selection pressures for increased brain size must have been considerable for additional energy to be made available. The normal human

Years ago Average brain

Growth in brain size in humans and chimpanzees

for

Changes in hominin brain volume over time

450

520

3(cmsiBrainze) 02 46 8101214161820 130011001003005007009001500

Homo heidelbergensis 0.2 1250

Homo neanderthalensis 0.05 1512

Paranthropus boisei 1.5 515

14001600120010008006004002000

Mean volume of 400 cm3 chimpanzees

adult brain averages around 1335 cm3, but ranges between 1000 and 2000 cm3. But intelligence is not just a function of brain size. There are large mammals, such as elephants and whales, with brain volumes greater than ourselves and yet are (arguably) not considered to be as intelligent. It appears that relative brain size is the important thing (brain size relative to body size). Modern humans have a brain volume three times that predicted for an ape with our body size.

Australopithecus africanus 2.5

Homo rudolfensis 2.0 700

Homo naledi 1.8?

151 4.0 3.0 2.0 1.0

Homo erectus 0.5 1016

Australopithecus afarensis 3.5 457

Homo floresiensis 0.05 380

Hominin species

Brain size vs body height in hominins

4. Comment on the significance of the brain/body size growth curve in humans compared with other primates:

Photocopying Prohibited

Brain size vs body height in hominins

(b) Comment on the significance of the Flores finds:

Frontal lobe Height (m) 3(cmvolumeBrain) 1000500015002000 1.00 1.25 1.50 1.75 2.00

f Brain size can be correlated with body height in hominins. Three distinct clusters emerge, indicating three phases of evolutionary development.

f Homo floresiensis, found on the Indonesian island of Flores, clearly falls outside these clusters. Its brain size to body size ratio is similar to that of the Australopithecines, but key aspects of its morphology, such as its small canine teeth and organisation of the brain, identify it as Homo. In addition, the Flores finds were associated with relatively advanced stone tools.

ErectinesAustralopithecines

A. afarensis

Homo floresiensis Homo naledi

3. Explain the significance of the high energy requirement of a relatively large brain:

7. What evidence is there that human brain expansion was associated with a beneficial mutation?

Homo sapiens

H. sapiens

5. (a) With respect to the brain size: body size ratio, comment on the position of H. floresiensis with respect to other hominins:

6. There is no firm date for H. naledi. Based on your plot opposite, what approximate date would you assign to this fossil?

Broca’s area Controls the lips, jaw, tongue, palate, and during speech. 978-1-927309-56-8

• Diet probably included vegetable matter and some meat (probably from scavenging)

• Reduced canine teeth

2. What is one possible purpose of the chin in modern humans?

• Thin tooth enamel

• Shortened jaw, allows large bite force to be generated with little effort

Early hominins Late hominins

• Dental arcade more like H. sapiens but still intermediate

Key Idea: Changes in dentition (the type, number, and arrangement of teeth) and jaw structure of our hominin ancestors can reveal information about our evolution. During early hominin evolution teeth (especially the molars) and jaws tended to be large. The paranthropines are the extreme example of this trend. Their diet of coarse vegetation required very large and powerful jaws and molars. During

• Diet probably consisted of fruits with some tougher material

Adaptations to a coarse diet

• Relatively large jaw

Australopithecus afarensis

Dental formulae all follow: I-2, C-1, P-2, M-3

Reduced size of canines permitted rotatory action, helping to grind coarse food up.

Massive molars and grindingaidedpremolarseffectiveaction.

• Thick tooth enamel

Photocopying Prohibited

Homo habilis

Paranthropus boisei had jaws and teeth adapted to a diet of very coarse vegetation and hard seeds. Their jaws produced a massive bite force of 2161 newtons, which helped to break food up. A modern human's maximum bite force is 777 newtons.

The reduced size of the incisors provides more room for molars.

152 LINK 150

• Thick jaw bones

1. Describe the general trend in the evolution of hominin teeth:

In many primates, the canine teeth are used in behavioural and social interactions, especially in species which show marked sexual dimorphism. Threat gestures, such as yawning (above), help maintain social order.

Teeth had a very thick coating of enamel to protect them.

• Small molars adapted to chewing cooked and soft food

Trends in Dentition

KNOW

212

• Large molars and incisors

• Thick tooth enamel

the course of hominin evolution, there was a general trend for a reduction in the size of the teeth tooth and jaw. This was a likely consequence of including a greater proportion of cooked foods, which required less chewing, in the diet. The teeth of modern humans are relatively small and generalised, reflecting an omnivorous diet of mainly processed (e.g. cooked) foods.

• Diet probably included vegetable material and a large proportion of meat

• Thick tooth enamel

• V-shaped dental arcade

• No chin

• Relatively large molars

• Parabolic dental arcade

The L shape of the jaw and the position of its joint allows the molars and premolars to meet at the same time giving an effective chewing action.

• Relatively large canine teeth

• Chin reinforces jaw, but leaves room for tongue muscles

• Parabolic dental arcade

Homo sapiensHomo erectus

Images redrawn from Lovejoy,

et al Science, vol 326, 2009

Socket joint for femur

Hand: Analysis of the hand of Ar. ramidus shows that it is similar to our own, and that human hands are therefore close to the primitive form and not as greatly modified for tool use as was previously thought. Ar. ramidus had a flexible wrist and the opposable thumb was well developed. By contrast, chimpanzees move on the ground by knuckle walking, a motion that requires strengthening of the wrist and knuckle bones and lengthening of the palm, making the hand less flexible and not as dextrous.

Well thumbdeveloped

Lack Short,strengthenedofknucklesflexiblepalm

Skull: The skull of Ar. ramidus shares certain features with Australopithecus, including a reduction in the size of the canine teeth in both male and females. This implies a reduction in aggression between males. The orientation of the base of the skull on which the brain stem rests suggests that the parts of the brain involved in visual and spatial perception were already beginning to develop.

C. Owen

Ardipithecus ramidus pelvis

Features associated with bipedalism that are shared by Ardipithecus and Homo

The first fossils of Ardipithecus ramidus were discovered in the Middle Awash region of northeastern Ethiopia in 1994. After many years of excavation, a partial skeleton was unearthed. Studying the skeleton of Ar. ramidus is beginning to change

Prognathicmuzzle

153

ThecanineReducedteethprimitive

side

Key Idea: Analysis of the skeleton of Ardipithecus ramidus has produced findings that suggest bipedalism and a manipulative hand are very ancient features.

Big toe forwardpoints

our understanding of hominin evolution. Until recently, it had been theorised that our earliest ancestors moved about very much like the chimpanzees of today. However the evidence from the Ar. ramidus skeleton shows that this is not the case and that bipedalism developed in quite a different way to what was once thought. Moreover, a dextrous hand developed early and is also an ancient trait.

handHuman

features of the Ardipithecus hand that are shared with Homo

The Importance of Ardi

Pelvis: The pelvis of Ar. ramidus indicates that the modern pelvis, evolved for bipedal locomotion, began its evolution in the trees. Although several features of the upper pelvis strongly indicate bipedalism, features of the lower pelvis show that muscles associated with tree climbing were still well developed

Relatively small cheek bones

The foot is rigid in both Ardipithecus and Homo Human pelvis

Chimpanzeepelvis

Ardipithecusramidus foot

metacarpalsShort

Big toe the

Foot: The foot of Ar. ramidus is a generalised one, with some human-like features, such as a rigid foot, as well as some modern ape-like features, such as an opposable big toe. These features indicate that Ar. ramidus spent considerable time climbing in trees.

Homo sapiens foot

points to

Brow ridge

Feature associated with tree climbing that is shared by Ardipithecus and Pan

Ardipithecus ramidus skull features

evolutionary

- Terrestrial biped

1. Describe the evidence for reduced aggression between Ar. ramidus males:

4. How does having a generalised body plan increase possible evolutionary pathways?

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- Skilled climber

- Canines larger in males

Ardipithecus

- Woodland and forest omnivore

ISBN: 978-1-927309-56-8

- Multiple environment omnivore

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Gorilla

Pan (chimpanzee)

- Short flexible palm and wrist

- Knuckle walker

- Strengthened wrist and elongated palm

- Short stiff back

- Canine teeth in males larger than in females

Homo - Habitual upright walker

- Small canine teeth in males

This simplified evolutionary tree of hominids shows that chimpanzees have continued to evolve into a specialised tree climber and are not simple modifications of the Chimpanzee-human Last Common Ancestor (CLCA). Indeed, the CLCA was an ape-like creature with many generalised features that have undergone further modification in both humans and chimps alike.

Proposed tree with

- Flexible, grasping feet

- 'S' shaped flexible lower back

Ardipithecus

- Large incisors for eating fruit

- Similar body size in both sexes

- Facultative upright walker

- Able tree climber

- Similar size in males and females

3. Describe the evidence for bipedalism developing in a primarily arboreal (tree-dwelling) ancestor rather than in a knuckle walking, terrestrial ancestor:

Chimpanzee-human Last Common Ancestor (CLCA)

- Retained long flexible lower back

- Small canines in males

2009326,volScience,aletLovejoy,OwenCfromModified

- Long, flexible lower back

- Palm walking tree climber (not brachiating or knuckle walking)

2. Explain why the human hand might now be viewed as the primitive type:

- Similar size in males and females

Retention of head hair

About 3 mya, the vegetation patterns in East Africa began to favour open grasslands, with fewer forested areas. This environment would have provided fewer opportunities for shelter from the sun, creating a selection pressure for the refinement of several thermoregulatory mechanisms.

both evolutionary responses to the changing climate of East Africa about 7-3 mya. However, a 2009 analysis of the 4.4 mya Ardipithecus fossils indicates that these very early hominins were still primarily forest dwellers, so any current hypotheses must account for the emergence of bipedalism in a forested environment. The Ardipithecus finds indicate that bipedalism was strongly associated with provisioning, and was later reinforced by a move into less forested habitats as savannah became established throughout Africa in the later Miocene.

Provisioning as a selection pressure

1. What advantages might an early human ancestor have gained by adopting a bipedal stance?

The first major step in the evolution of humans as a distinct group from apes was their ability to adopt the habitually upright stance we call bipedalism. Closely linked to this shift was the reduction in body hair. A number of selection pressures for hair reduction are described below (left). Early studies suggested that bipedalism and hair reduction were

Key Idea: Bipedalism provided advantages such as better provisioning, greater safety, and greater efficiencies in locomotion and thermoregulation.

An upright posture may have helped early hominins to see predators or locate carcasses at a distance.

Carrying offspring

Shorter, finer hairs (not hair loss) in early hominins would have allowed greater heat loss via radiation from the skin surface. Well developed sweat glands in humans enable heat loss at 700 watts m-2 of skin (greater than any other mammal).

2. (a) What selection pressures are likely to have been important in the evolution of bipedalism initially?

(b) What environmental changes could have reinforced the advantages of bipedalism to human ancestors?

Efficient locomotion

Upright walking exposes 60% less surface area to the sun at midday and there is greater air flow across the body when it is lifted higher off the ground.

Hair reduction Bipedalism

Walking upright enabled early hominins to carry their offspring, so the family group could move together.

Parasite control

Tool use was probably a consequence of bipedalism, rather than a cause. Upright walking appears to have been established well before the development of hunting in early hominids.

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Seeing over the grass

Bipedalism and Nakedness

Thermoregulation

A reduction in body hair would have made it easier to control external parasites such as fleas and lice. This would have been increasingly important when early hominins began to use a 'home base'. Many external parasites need to complete their life cycle at a single location so that hatching eggs can reinfect their host.

Once bipedalism was established, changing habitats would have provided selection pressure for greater efficiency. Being able to move across the growing savannah without expending large amounts of energy would have offered a great survival advantage.

Thermoregulation

The ability to carry food while walking seems to have been important in the initial development of bipedalism. Females would have favoured males able to provide energy-rich foods, which would improve offspring survival and increase reproductive rate. The ability to carry food from its source to a place of safety would have had a great survival advantage.

Holding tools and weapons

Hair on the head and shoulders has been retained to reflect and radiate heat before it reaches exposed skin.

KNOW

Chimpanzee in standingspineStraightposition

pelvisFemoral

Humans have several notable skeletal adaptations for bipedalism that chimpanzees lack. The foramen magnum is centrally positioned on the bottom of the skull, helping it balance on top of the spine. The spine is S-shaped. This brings the centre of gravity in line with the body and helps to cushion the forces acting the on the body during walking and running. The femoral head is angled so that the knee is positioned under the centre of the body which helps the body remained balanced during walking. The pelvis is short and broad, providing attachments for the large gluteus muscles that assist with keeping the body upright.

1. Describe the features of the human skeleton that are adaptations for bringing the body in line with the centre of gravity:

Key Idea: Important changes in the skeleton are associated with the move to bipedal locomotion in early hominins. The features of the human skeleton that help it maintain a bipedal posture are best seen when compared to the habitual knuckle walker, the chimpanzee (below). Chimpanzees are

ISBN: 978-1-927309-56-8

Chimpanzee

likespineS-shapedactsaspring

Foramen magnum (FM) toward the back of skull

Long narrow pelvis

Broad, basin-like head angled and strengthened

Human

Chimpanzee

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Comparing humans and chimpanzees

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Gluteus muscles prevent tilting when the opposite leg is off the ground. The carrying (valgus) angle ensures the knee is brought under the body during walking.

Foramen magnum (FM) further forward so the skull balances on the spine

ChimpanzeeChimpanzee Human Human Human

adapted for climbing rather than upright walking. They can walk on two legs but with difficulty and with a lurching gait. The evolution of the human skeleton has brought the body in line with the centre of gravity. This allows a person to walk without tilting to the side or backwards and forwards.

Adaptations for Bipedalism

Chimpanzee foot

3. Describe features of each of the following in A. afarensis that provide evidence of bipedalism:

Curved toe bones

Big toe diverges (well separated from other toes

Human Australopithecine

(b) Knee joint:

Big toe aligned with other toes (not opposable)

Human foot

Large heel bears increased weight

condyleLateral Inner condyle(medial)

End of femur at the knee joint

Biped: S-shaped spine and forward FM. Femur (thigh) is angled out from knee (the carrying angle). A longer femur provides a longer, more efficient stride.

Quadruped: Straight spine and rear-ward FM, femur is at right angles to knee so an upright stance is less stable.

Foot bones (OH8) from Bed I at Olduvai Gorge

End of femur at the knee joint

Australopithecine footprints

Direction of duringtransmissionweightwalking

The human foot is adapted as a weight bearing platform rather than a grasping structure. The toes are reduced relative to those of chimpanzees. The foot is arched so transmits weight from the heel, along the outside of the foot, across the ball and through the big toe. This weight transference conserves energy during locomotion.

The australopithecine foot had an aligned big toe, as in humans, making it difficult if not impossible to grasp branches with the hindlimbs. The heel bones that have been found also indicate habitual bipedalism. Computer simulations suggest that A. afarensis could walk like humans but could not have walked like a chimpanzee.

Lighter representsshadingpoints of contact with the ground

Evidence that Australopithecus afarensis was bipedal

Chimpanzee

2. Study the images of the human and chimpanzee foot in this activity. What features of the human foot produce an efficient platform for walking? Contrast these with the chimpanzee foot.

End of femur at the knee joint

The foot of a chimpanzee has relatively long, curved toes, with an opposable big toe adapted from grasping but ill-suited to upright walking. The foot transmits weight from the heel, along the outside of the foot, and then through the middle toes.

Lighter representsshadingpoints of contact with the ground

(a) Foot:

buttressBony

Heel bone missing from fossil

Lucy’s lumbar vertebrae were broad for effective weight transmission from the upper body to the pelvis. The australopithecine spine had an S shaped curvature, similar to that of modern humans.

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Shape of the tooth row (dental arcade) is half way between the straight-sided U-shape of an ape jaw and the more rounded, parabolic shape of a human jaw.

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Analysis of Lucy's Skeleton

*Lucy is the name given to a specimen of Australopithecus afarensis

Arched feet, wide heels, and big toes aligned with the other toes and not opposable.

The foramen magnum was much further forward than in apes and much closer to the position in humans.

The reconstruction of Lucy (Australopithecus afarensis), below, shows the skeletal features of an early bipedal hominin. Lucy still possessed ape-like features but she was a fully-bipedal hominin with all the adaptations associated

Lucy’s* ape-like characteristics

Butressing of the knee was more similar to humans than to apes.

Lucy’s bipedal features

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comparedArmsHighlyHighlyToesRelativelyCurvedFunnel-shapedquadrupeds.chest(thorax).fingerbones.shortlegs.arelongandcurved.mobileanklejoint.mobilewrist.relativelylongtolegs.

Lucy’s limbs showed human-like features consistent with bipedalism. The femoral (valgus) angle was similar to humans, bringing the knees under the body.

Shoulder joint orientated towards the head, similar to the orientation in chimpanzees and other arboreal

1. When she was discovered, Lucy was labelled "the missing link" by media, highlighting the fact her skeleton showed both ape-like and human-like features. Describe the features that show Lucy was habitually bipedal and contrast these with features that show her ape ancestry:

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Lucy’s pelvis was broad and basin shaped, similar to a human pelvis. It would have supported the upper body when upright.

with bipedal locomotion. Although there is no doubt that Lucy was habitually bipedal, a number of skeletal features suggest that tree climbing was still an important part of this hominin's niche, perhaps associated with escape, security, or foraging. A. afarensis is an important because she shows transitional stages between earlier apes and modern humans.

Key Idea: The skeleton of Australopithecus afarensis shows both advanced and primitve features.

Hominin Data Sheets

from C. Owen Lovejoy et. al, Science, vol 326, 2009

the data that you have collected. The data sheets for each hominin have some clearly defined places for answers. Use the ‘Additional notes’ box for comments on culture, skeleton, habitat, etc. It is useful to make comparisons between hominins dated immediately before and after the one you are making notes about. Note that extra information is provided here: you are not required to provide detail for every species. The trends are important.

Skull features

(f) General bone thickness and limb proportions.

(e) Evidence of artistic expression (e.g. rock paintings, carvings, statues) and their significance.

Geographic distribution

Describe the nature of the habitat of the hominin if known. This may be African open savannah for the earlier forms but may include more varied habitats (sub-tropical forests, temperate forests, tundra, and even subarctic) for the later, more widespread hominins.

Skeleton

(d) Depth of rib cage.

(d) Evidence of using fire (e.g. to cook (hearth), to hunt, for security from predators).

(a) Structure of the pelvis: shape, size of birth canal.

(g) Evidence of spoken word (voice box development), written word, higher technologies for communication.

Redrawn

(f) Evidence of abstract thought, spirituality and religion (e.g. burials, cannibalism).

The various hominin species each have characteristic cultural features. Consider the following points:

(a) Stone tool technology used.

This section mainly deals with what is called the post-cranial skeleton; the skeleton apart from the skull. Various features can be investigated:

Note the size of the skull, the shape of the braincase and face. The size and shape of the jaw and the dentition and the implications of these on diet.

(e) Structure of the foot; evidence for adaptations for walking and primitive features if present.

Key Idea: The following data sheets will help you consolidate information on the various hominin species. This exercise will allow you to collate the information on various hominin species from a wide range of sources. The data summary sheets give you space to describe key features and points on each species. Your descriptions should be brief; in many cases, key words or brief sentences will be all that is required. Below are some ideas on how you can analyse

Ardipithecus existed from 5.8 to 4.4 million years ago. It stood 1.2 m high and weighed around 50 kg. The brain case was small, at around 350 cm3, and the jaw had reduced canine teeth. Fossils of the pelvis show it was capable of being bipedal but it still had an opposable toe and spent time climbing. The hand was characterised by a short palm and a flexible wrist. Ar. ramidus was probably an omnivore and fruit eater.

= Fossil sites Height:Years: BrainWeight:size: mkmyagcm3 Geographic distribution: Additional notes: Africa Asia Europe Australia Ardipithecus ramidus

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List the regions (e.g. east Africa, Asia) or the countries (e.g. Kenya) where fossils of the species have been found to date. The sites are marked on the map with a triangle.

(b) Other materials used (wood, bone, ivory, clay for pottery, copper, bronze, iron, precious metals).

(b) Angle of the femur (thigh bone) and the knee joint.

Culture

Habitat

Composite reconstruction

Australopithecus sediba was discovered in cave deposits at the Malapa site in South Africa. Features seen in the brain, feet, hands, and pelvis of A. sediba suggest this species was on the direct evolutionary line to Homo. However, it also exhibits australopithecine features such as long upper limbs and a small cranial capacity of about 420 cm3

Australopithecus anamensis

A. anamensis was discovered at Kanapoi, Kenya. The find consists of complete upper and lower jaws, teeth from several individuals, a piece of skull, arm bones and a leg bone. A. anamensis existed between 4.2 and 3.9 mya. The teeth and jaws are similar to older fossil apes. The lower leg bones, however, show strong evidence of bipedalism and the upper arm bone is extremely human-like.

Australopithecus sediba

A. afarensisA.garhi2.53.5Mya

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sites Europe Asia

A. afr icanus 2.0 Fossil Africa

Some researchers claim such differences suggest two separate species, not sexual dimorphism. Nicknames: Lucy, The First Family, Laetoli footprints.

A. afarensis existed between 3.9 and 3.0 mya. The skull is similar to that of a chimpanzee, except for more human-like teeth. Brain size 375-550 cm3. The humanlike pelvis and leg bones confirm they were bipedal. Height ranges from 1.0 to 1.5 m, weight 29-42 kg (sexual dimorphism).

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= Fossil sites =

Small, gracile, small-brained, and bipedal,

Australopithecus afarensis

Artist's reconstruction

Australopithecus spp.

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Africa Asia Europe Australia Geographic

This find, made in Ethiopia, is known from a partial skull. This skull, dated at about 2.5 mya, differs from other species of Australopithecus in its combination of features: the primitive skull shape and extremely large size of the teeth (especially molars). The brain case is 450 cm3. Stone artefacts found nearby suggest this hominin may have used tools before Homo habilis

International

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Additional notes: distribution:

Australopithecus garhi

ProfbergerCourtesyEloff.Brett4.0CCUniversityWitsand Ji-Elle CC 3.0 GuérinNicolasCC3.0

Height:Years:

Artist's reconstruction

Additional notes:

Sts 5 skull from Sterkfontein South Africa

Height:Years:

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Paranthropus boisei

Geographic distribution:

One of a group of robust species of early hominin. Existing between 2.1 and 1.1 mya, it had a brain size of 500-545 cm3. Weight 34-49 kg and height 1.24-1.37 m (sexually dimorphic). Known for its massive jaws, large molars, and attachments on the skull associated with chewing muscle. Probably fed on a tough diet of low grade foods: tubers, grains, and other plant material. This species is also referred to by some researchers as Australopithecus boisei

Africa Asia Europe Australia

Australopithecus africanus

Artist's reconstruction

Additional notes: Africa Asia Europe Australia Geographic distribution:

= Fossil sites

A. africanus existed between 3.0 and 2.0 mya. Similar to A. afarensis, it was also small, gracile, and bipedal, but slightly larger in size. Brain size may also have been slightly larger, ranging from 420 to 500 cm3. Weight 40 kg, height 1.3 m. Generally considered to be specific to South Africa. Differs from the early australopithecines in east Africa by having larger back teeth and smaller canines. The jaw shape is human-like.

BrainWeight:size: mkmyagcm3

mkmyagcm3

Height:Years:

BrainWeight:size:

Additional notes:

Additional notes: Africa Asia Europe Australia Geographic distribution:

Africa Asia Europe Australia

Height:Years:

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KNM-ER 1813 skull from Koobi Fora region to the east of Lake Turkana, Kenya

BrainWeight:size:

= Fossil sites

H. habilis existed between 2.4 and 1.5 mya. Although similar to australopithecines in many ways (e.g. height of males is 1.3 m, weight 40 kg), their brain size was considerably larger (500 to 800 cm3). Some researchers argue that this species is too variable in its present classification. Instead, they propose that it be split into two species: Homo habilis (ER-1813, shown below) and the more robust Homo rudolfensis (ER-1470). One H. habilis brain cast shows a bulge of the Broca’s area, suggesting rudimentary speech.

mkmyagcm3

SK 48 from Swartkrans in South Africa

Geographic distribution:

Artist's reconstruction

Homo habilis

Artist's reconstruction

Paranthropus robustus

P. robustus lived 2.0-1.5 mya and had a brain size of about 520 cm3. It had similar body proportions to A. africanus, but a larger and more robust skull and teeth. Height 1-1.2 m and weight 40-54 kg (sexually dimorphic). The massive face was flat or dished, with large brow ridges and no forehead. Massive grinding teeth set in a large jaw suggest that it probably fed on a diet of tough, coarse plant food that needed a lot of chewing. May have used bones as digging tools. Some researchers classify this species as Australopithecus robustus.

= Fossil sites

Additional notes: Africa Asia Europe Australia Dmanisi H. georgicus exhibited strong sexual dimorphism; the males were considerably larger than the females. This is quite a primitive trait, and not observed to the same degree in later more modern hominins such as Homo neanderthalensis

Additional notes:

BrainWeight:size: mkmyagcm3

Fossils found in Dmanisi, Georgia in 2002 were originally classified as H. ergaster, but size differences have since lead to the new classification Homo georgicus. The fossils, which include four skulls and several jaw bones have been dated at 1.8 mya. The small size (1.5 m tall and ~50 kg) and cranial capacity (600-780 cm3) of the fossils place H. georgicus as a descendent of H. habilis and predecessor of H. erectus. Tooth-wear patterns indicate an omnivorous diet. They may have been the earliest hominin to venture out of Africa, some 800,000 years before H. erectus. This finding challenges the theories that hominins required a large brain and advanced tool making skills to be able to migrate out of Africa.

= Fossil sites

Height:Years:

Artist's reconstruction

Africa Asia Europe Australia

Larger brained than previous Homo species, with volumes of 850 to 1000 cm3 Previously considered to be part of Homo erectus, but now thought to be a separate species. Homo ergaster refers to what used to be called early African forms of Homo erectus, existing 1.8 to 1.4 mya. Earliest hominin with human-like body proportions. A nearly complete skeleton of a 9 year old boy was 1.6 m tall (estimated 1.8 m and 60 kg adult size).

Height:Years:

Geographic distribution:

www.skullsunlimited.com

D2700 (skull), and D2735 (lower jaw) of Homo georgicus from Dmanisi, Georgia

BrainWeight:size: mkmyagcm3

Geographic distribution:

KMN-ER 3733 skull from Koobi Fora region to the east of Lake Turkana, Kenya

Homo ergaster

Homo georgicus

Homo erectus

Additional notes:

Some anthropologists argue that Homo floresiensis is a microcephalic, or malnourished version of modern H. sapiens. However, variations in its teeth, lack of chin, and low twist of the forearm bones lend support for a new species.

International

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Homo erectus pekinenis or 'Peking Man' from Zhoukoudian Cave, near Peking in China

= Fossil sites

Homo floresiensis

mkBrainWeight:size:gcm3

Africa Asia Europe Australia

Geographic distribution:

A nearly complete skeleton (LB1), with a mix of primitive and derived features, was discovered on the Island of Flores, Indonesia, and named Homo floresiensis. The specimen, was small, 1.06 m tall, and weighed only 25 kg. It also had a very small brain capacity (only 380 cm3).

Artist's reconstruction

www.skullsunlimited.com

LB1 skull from Liang Bua Cave, Flores Island, Indonesia Fossil sites

Homo erectus is reserved for the later Asian forms (shown here), with dates ranging from 1 million to 300,000 years ago. At one time thought to be the first humans to venture out of Africa (but see H. georgicus). They differ from H. ergaster by having skulls that were strongly buttressed with ridges of bone, skull walls greatly thickened, and larger brain volumes (range: 1000 to 1250 cm3). Height 1.7 m and weight 60+ kg. These simple huntergatherers used stone tools and fire.

Africa Asia Europe Australia

Height:Years:

Additional notes:

Subsequent H. floresiensis fossils have been found in conjunction with tools and remnants of fire indicating that the species had advanced behaviours. Fossils have been dated at 100,000-60,000 years.

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mkBrainWeight:size:gcm3

Geographic distribution:

Height:Years:

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Europe Africa Asia Australia

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Additional notes:

Geographic distribution:

Homo antecessor, a highly controversial species, dated 780,000-625,000 years ago. Discoveries at the Gran Dolina site in the Sierra de Atapuerca, Spain, make these the earliest known European hominin specimens. Fossils consist of nearly 80 postcranial, cranial, facial, and mandibular bones as well as teeth of at least six individuals. H. antecessor (‘pioneer’) shows a mixture of primitive and modern traits, with an especially modernlooking midface. Brain volume 10001150 cm3, height 1.6-1.8 m, weight 90 kg.

Homo antecessor from Gran Dolina, Sima de los Huesos in the Sierra de Atapuerca, Spain

Artist's reconstruction

Additional notes: Africa Asia Europe Australia

= Fossil sites

Height:Years:

Geographic distribution:

Too few fossil fragments have been found for scientists to put together a physical description of the Denisova hominin.

mkBrainWeight:size:gcm3

Homo

Fossil fragments (tooth, finger bone, and toe bone) belonging to a previously unknown species of Homo were found in the Denisova cave in Altai mountains, Siberia, Russia. Carbon dating estimates their age at about 40,000 years. The Denisova hominin existed at the same time as modern humans and Neanderthals. The Denisova hominin has yet to be classified as a new species.

Homo sapiens rhodesiensis or 'Rhodesia Man', from Broken Hill Mine, Kabwe in Zambia

heidelbergensis

Homo heidelbergensis is probably a group of related but variable subspecies. Formerly known as archaic humans they have both modern and more primitive features. It is likely that both modern humans (in Africa) and Neanderthals (in Europe) evolved from this species. They had brain sizes ranging from 1100 to 1400 cm3. Height ~1.8 m, weight ~65 kg.

Denisovan fossils

Height:Years: BrainWeight:size: cmg3

The first anatomically modern humans (AMH) appear about 160,000 years ago in southern African and the Middle East. Average brain volume 1335 cm3, height 1.75 m (males), weight 70 kg (males). Skeleton gracile. Humans underwent a sudden cultural revolution about 40,000 years ago, with the appearance of Cro-Magnon culture. Using a wider range of materials, their tool kits became markedly more sophisticated. They were skilled hunters, tool-makers and artists (cave art and music).

Geographic distribution:

'Cro-Magnon Man', from Cro-Magnon, Dordogne Valley in France

Homo neanderthalensis

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Additional notes: Africa Asia Europe Australia

mkBrainWeight:size:gcm3

Artist's reconstruction

La Ferrassie Skull, Le Bugue, Dordogne Valley in France

Geographic distribution:

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Height:Years:

mkBrainWeight:size:gcm3

Additional notes:

Neanderthals existed between 230,000 and 30,000 years ago. Average brain size was 1512 cm3 and they had short, squat, cold-adapted bodies with thick, heavy bones (height 1.5-1.7 m, weight 66-78 kg). Neanderthals and modern humans separated between 700,000 and 400,000 years ago, but there was probably some gene flow between nonAfrican humans and Neanderthals as recently as 100,000 to 50,000 years ago.

Height:Years:

Homo sapiens

Artist's reconstruction

Africa Asia Europe Australia Okladnikov

HINT: Adaptations for bipedalism. Selection pressures for bipedalism.

HINT: General features of primates. Features of a dextrous hand.

Trends in skull anatomy

Adaptations for bipedalism

HINT: Changes in skull size, brain volume and dentition.

Primate characteristics

Compare the foot structures above. Use the diagrams to analyse and describe the evidence that Australopithecus afarensis was bipedal. Discuss the selective advantages of being bipedal within the environment in which Australopithecus afarensis evolved. You may use more paper if required.

Australopithecus afarensis foot

Human foot

Chimpanzee foot

NCEA Style Question: Biological Evolution

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1. The diagram below shows the foot of a chimpanzee, a human, and Australopithecus afarensis

Knowing, or wise man

Meaning:

Upright man

Name:

Homo habilis

2. Draw lines to match up the hominid name with its meaning, then match the name to the correct skull number (1-8 below).

Man from the Neander Valley.

Southern Ape from Africa

Homo erectus

Homo neanderthalensis

Man from the island of Flores or Flores man

Handy SouthernmanApe from Afar, Ethiopia

1. Using the dd information you have learned in this chapter, identify the fossils below: 48 cm

Australopithecus afarensis

Homo sapiens

Homo floresiensis

(b) The image below shows the top and rear of a non-human hominin skull. Annotate the photo and describe the features that identify it as non-human.

Australopithecus africanus

Skull number:

1 2 3 4 5 6 7

(a) Decide whether or not the jaw below is that of a modern human. Circle and annotate the photo to describe features to support your argument in the space below

Language to communicate ideas, plan survival strategies, and coordinate group activities such as resource gathering and hunting of increasingly larger game. Group bonding behaviour improves survival opportunities for members.

Producing artefacts from mental templates required an understanding of abstract ideas and physical processes: the fracturing behaviour of stone, angles of striking stone and how hard to strike, and the trajectory of a thrown projectile.

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Fierce predators

The modern human mind

Adopted niche

Cultural Evolution

Social intelligence

In response to these selective pressures humans evolved an upright stance with the head balanced on the spine and a large brain capable of learning, planning and passing on ideas. An upright stance freed the hands to grasp and manipulate objects in a very sensitive and precise way.

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behaviours also evolved as they were learned and passed on to offspring. This non-genetic means of adaptation, called cultural evolution, further enhanced the success of early humans.

Cultural forces

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Key Idea: Cultural evolution is a term used to describe the transmission of and changes to knowledge and ideas over successive generations. In addition to the physical evolution of humans, ideas and

Predominantly ground living, opportunist/ scavenger. Able to exploit a number of varied habitats and utilise a range of food resources.

The unique combination of brain and specialised physical features allowed early humans to learn from others and manipulate their environment to begin changing it to suit themselves.

Being able to predict, using current observations, the habits of potential game, the rhythms of the seasons, and the geography of the landscape (e.g. location of water sources and caves).

Technical intelligence

Climate change

Predators made a ground dwelling lifestyle dangerous. Early humans would have to develop solutions to protect themselves from attack.

Resulting physical features

Natural history intelligence

230

Creating artefacts and images with symbolic meaning as a means of communication. Using knowledge of animal habits, tools, advanced planning and communication to coordinate the hunting of large game.

KNOW

Over many millions of years, the evolution of human ancestors has been directed by natural selection. Environmental forces such as climate change, food supply, and predators, acted on the gene pool.

Environmental forces

1. What is cultural evolution?

The climate became drier and the forests which were the homes of the earlier primates gradually disappeared. This reduced shelter and meant that traditional food sources became scarce or disappeared. New food resources had to be investigated.

The move from opportunist scavenger to hunter-gatherer was a major stage in mankind's cultural evolution. It was taken in a series of small steps, over a very long time (perhaps a million years). A few human societies, such as the Australian aborigines last century, were still at this stage until very recently.

and

(e)

(f)

An increasing knowledge and expertise in genetics has made it possible to direct genetic change in other organisms, including our own species. Such abilities have many biological, ethical, and social implications.

The present and the future

Development of cities

Commerce and communication:

(CentralMaizeAmerica) Rice(MiddleWheatEast)(Asia)(CentralMaizeAmerica)

3. Explain how each of the cultural developments listed below enhanced the survival ability of early humans:

(CentralMaizeAmerica) (MiddleWheatEast) Rice

(b) Shelters

Donkey (CentralMaize America) (MiddleWheat East) Rice (Asia)

Sharing ideas became easier once people began living in cities and the technology developed to spread knowledge. Rapid developments in science and technology in the last 200 years have influenced almost every aspect of daily life and significantly increased the rate of cultural evolution.

2. Describe two probable effects of a drying climate on the selection pressures directing the evolution of early hominins:

(a) Manufacture of bone stone tools:

Cooperative hunting:

SheepGoat

and clothing:

(c)

Development of stable settlements

Use of fire:

As communities became larger, trade and commerce began to develop. Large cities grew up where markets and trading systems developed. These were places where people could develop special skills such as pottery and metal work. It also resulted in rivalry and, in some cases war, between states.

The success of humans as a species has presented modern populations with a number of complex problems (e.g. global pollution and over-population) and many ethical considerations. To live sustainably in a healthy environment, humans will need to change many of the current practices surrounding resource use and distribution.

Manipulation of the environment (e.g. damming rivers) allows humans to exploit resources in a way that wasn't previously possible. Medical advances have increased the human lifespan and advancements in technology have allowed humans to produce material goods at a staggering rate.

Development of agriculture:

Communities of grain cultivators became established. People lived in relatively large, permanent settlements. Such people developed qualities such as patience, industry, and a sense of property, preparing the way for further cultural evolution.

The knowledge explosion

(d)

Rice (Asia) (Asia) (MiddleWheatEast)

Development of agriculture

People learned to cultivate plants, especially grains, and domesticate animals. In the Middle East, about 8000 BC, they learned to grow wheat. In Mexico, about 500 BC, they began to grow maize.

Levallois

Chopper Proto-biface

Polyhedron Discoid

Mousterian tool culture

HandTheaxecore is the tool Side-on

Oldowan

Oldest dated stone tools

Timeline of stone tool technologies

needleBone Burin scraperSide bladeSolutrean Throwing stickmethodbladePunchFlake Core edgeworkedFinely Levalloisscraper

Cores

Trends in Tool Cultures

Handaxesidesfrom

Flakes removed from one side only

Flakes removed from two sides

Palaeolithic

Le Moustier France. Flint, 8.5 cm.

Acheulian MousterianUpperPaleolithic

Oldowan (pebble) tool culture

Made by H. erectus and archaic H. sapiens, these tools were typically 'tear drop' in shape and were crafted with a slight bulge on each broad surface (a bi-face). They ranged in size and are often referred to as hand axes although it is not clearly understood how they were used. They differ from the pebble tools in that there appears to be a standard design and each tool is manufactured using a great many more blows to remove flakes.

Key Idea: The development of stone tools is a defining characteristic of Homo. Particular, identifiable types can be matched with specific time periods and species. The Palaeolithic (Old Stone Age) is a period of early cultural development spanning the emergence of the first stone tools

methodCore Flake

Upper Palaeolithic tool culture

Biface shape: bulges outwards on both sides and has tear-drop shape

Acheulean tool culture

Flakes shown)(notand the cores are used as tools

3 mya 2 mya 1 mya Present3.3 mya 162 WEB 162 LINK 163

Probably made by Homo habilis, these were crudely fashioned river-worn pebbles. A minimum number of flakes were knocked off from several angles to produce a core with a cutting edge (e.g. chopper, discoid, polyhedron). Although the cores may have been used as tools, it is known that the sharp flakes were also useful in cutting.

There was a rather sudden increase in the sophistication of tool making about 35,000 to 40,000 years ago. Both the modern Homo sapiens and the last of the Neanderthals produced flint tools of much finer workmanship using a technique called punch blade. Long, thin flakes are removed and shaped into different tool types. A number of European sub-cultures, e.g. Solutrean, emerged. Other material such as bone, ivory and antler became increasingly utilised to produce very fine tools such as needles.

Flakes removed from all

about 3.3 mya in eastern Africa, until the development of sophisticated tool kits in the Mesolithic (Middle Stone Age) about 10,000 ya. These tool cultures are known mostly by their stone implements. While other materials, such as wood, were probably also used, they did not preserve well.

Made by Neanderthals and more refined than Acheulian tools. Flint became commonly used. This stone would chip in a predictable way when struck with another hard object so finer workmanship was possible. A particular technique from this period is known as the Levallois method. It involves the preparation of a core and striking off a large oval flake which is then retouched on one surface only (see the photograph on the right; the retouched surface is visible).

Cleaver view

1. Name the culture associated with each of the tools above (A-D) and describe the features that help identify them:

3. Describe the general trends in the design of the stone tool from Oldowan to Upper Palaeolithic cultures:

(a) Oldowan:

(b) Acheulean:

5. Name the materials used to make tools in the Upper Palaeolithic culture that were seldom used in earlier cultures:

(d) Tool D culture:

2. Identify the hominin species associated with, and the approximate time period for, each of the tool cultures below:

(d) Upper Palaeolithic:

4. The tools that are recovered from early human prehistoric sites are almost invariably stone, bone or ivory. Explain why tools made from other materials are almost never recovered from these sites:

(a) Tool A culture: (b) Tool B culture: (c) Tool C culture:

A D C B

The curved, sharp edge of this tool would probably have been used to shave wood chips from spear heads.

(d)

It is possible to infer how the stone tools of early hominins were used by studying how similar tools have been used by recent 'stone age' societies. People using only stone-based technology were still in existence well into the first half of last

century. Hunter-gatherer people existed in places like the Kalahari desert in south west Africa, the Australian outback, and some of the more remote areas of South East Asia and South America. Anthropologists studying these primitive cultures gathered valuable insights into how our ancestors may have lived.

1 2

The sharp narrow point of this tool makes it an effective drill when twisted back and forth. In this way, holes could be made in materials such as hides, wood, and ivory.

(e)

Used as a knife, this tool had only one side with a sharp cutting edge so that pressure could be applied to the blunt edge.

Hafted to a pole with greased sinew or plant fibre, this flint tool would have provided an effective cutting edge for the spear.

This tool was probably used to scrape the fat and sinew from the underside of a freshly killed animal, in preparation for curing.

A simple tool used as an axe, probably to cut into wood or possibly to dismember a carcass.

Palaeolithic Tool Use163

(g)

Later forms of this tool were probably used to skin and dismember carcasses.

234

Description

Photocopying Prohibited

No. Name of tool

(c)

(h)

(a)

(b)

Key Idea: Stone tool technology can be adapted for numerous purposes including spear heads, blades, and axes.

1. First match each of the diagrams above with the description of their function in the table below (place 1-8 in number column). Secondly, assign each tool with its correct name from the list below: Side scraper, borer, denticulate tool, spear point, chopper, backed flake, early hand-axe, late hand-axe

Early forms of this tool may have been used as a pick-like tool to expose root tubers growing under plants.

(f)

Fire may also have been used as a hunting tool by setting fire to forests to drive out game. Fire could also be used for protection to drive off

started by natural events such as lightning. Whatever its origin, the controlled use of fire changed the course of both physical and cultural evolution, influencing dietary range and improving survival. Possible evidence exists for the use of fire up to a million years ago, but real evidence of controlled use of fire dates back only a few hundred thousand years.

Fire

Key Idea: The controlled used of fire by early humans allowed them to eat a greater range of foods and to expand their range into darker and colder places. Just when and how early human ancestors began using fire is debated and may never be precisely known. It is likely that early fire was "captured" from the wild, e.g. from fires

Naturally set fires were the most likely source of early fire. Burning embers may have been carried back to home sites, or the fire used where it was.

2. (a) Describe two important consequences of cooking food: (b) Explain how cooking food provided a selection pressure for a smaller jaw and teeth:

164

A not so obvious, but important use of fire, is its use in the construction of weapons. Wooden spear tips can be hardened in fire, allowing them to be made sharper and improving their penetrative power. Rocks heated in a fire become brittle and are therefore easier to shape into tools, such as blades and spearheads. The blade also holds a sharper edge.

light and can be used as a torch, allowing early humans to explore dark places such as caves. It may have helped with bonding, such as sitting around a campfire. Fire provided light and warmth at night.

Cooking is the most obvious use of fire. Cooking food makes it easier to chew and digest, releasing energy more quickly for the body to use. Fire also kills parasites and pathogens in the food. Fire can also be used to preserve food. Meat can be smoked and vegetable material can be dried.

The development of the hand-drill meant early humans could make fire when and where they needed it.

Firepredators.provides

3. Discuss the influence of fire on human cultural evolution:

1. List four uses of fire:

WEB 164

Key Idea: The development of clothing and techniques to build shelters allowed the expansion of humans into colder climatic areas.

body hair. However this then limited the ability to survive in cold climates as humanity migrated north out of Africa into Europe and beyond. The use of animal skins or woven plant material to make clothing provided a way of keeping warm. Building shelters allowed humans to shelter from both the weather and possible predators.

ISBN: 978-1-927309-56-8

(b) Identify the evidence for humans making clothing:

Although often called cavemen, human ancestors probably didn't start using caves regularly as shelter until they could control the use of fire. Bones of early australopithecines or Homo found in caves were likely taken there by predators or been washed in by ancient streams. Some of the first evidence of caves being used by humans is from the Atapuerca cave in Spain. It is dated at 1.2 million years old, but it is difficult to tell the exact relationship of the fossils to the cave.

3. What is the main purpose of clothing?

Shelter and Clothing

Early humans and their ancestors are often depicted in popular texts wearing animal skins. However there is little direct evidence of humans wearing clothes until 26,000 years ago (the evidence is a finely worked bone needle). Evidence from burial sites also shows humans were adorning themselves (or at least their dead) with necklaces as far back as 35,000 years ago. The divergence of head lice and body lice (which live in clothes) suggests human ancestors began wearing clothes some 100,000 years ago.

The first evidence of humans building purpose-built shelters dates to around 400,000 years ago. Post holes in the ground indicate poles were used as scaffolding for the shelter. Preserved bones from around 17,000 years ago in the Ukraine show humans there used mammoth bones and tusks as scaffolding, probably because there would have been few trees available to make wood scaffolding from.

This finely worked bone needle is almost identical in shape to needles used today. This needle is dated between 17,000 and 10,000 years old.

LINK 161

2. Suggest a reason why caves where probably not regularly used by humans and their ancestors until the controlled use of fire was developed:

236

3.0CCDescouensDidier

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165

Hide drying on rack Rosino

KNOW

Human ancestors would have had a far greater amount of body hair than humans today. The move into hot open grassland provided a selection pressure for the reduction of

1. (a) Identify the evidence for humans building purpose built shelters:

Liang Bua cave, Flores Island, Indonesia.

f The Neanderthals of Europe and Southwest Asia buried their dead with signs of ritualisation. The position and orientation of the body are consistently the same and some graves included grave goods such as tools or animal bones (although the validity of grave goods with burials is disputed).

f Art requires at least some form of abstract thought. To take an image in the mind and draw it or model it in real life first requires the formation of the idea and then the use of technical skill and imagination to shape an object or draw an image.

Until recently, it was believed that art and spiritual beliefs first developed with the arrival of modern humans, particularly in Europe. However ancient artworks dating to nearly 300,000 years ago can be found outside of Europe. The beginning of a period 35,000 years ago marks a dramatic cultural development occurring simultaneously over large parts of

The evolution of art

f many paintings occur in places that are difficult to access, e.g. deep in caves and often on the cave roof.

Ancient paintings were created using natural pigments such as charcoal, manganese oxide, and ochre, which were applied to grease smeared on the rock surface. Although we can never be certain of what the artist was thinking at the time, it is likely that much of the ancient art had a religious or spiritual purpose. This can be hypothesised because:

Venus of Berekhat

Art and spiritualism

f The oldest known intentional human burial is dated at 100,000 years, in Israel. Artefacts found with the bodies suggest a ritual of sorts. Burials became more common as ancient humans spread over the globe. Burials also became more elaborate, at least for some. Recent comparisons of burial sites show that the majority were plain with simple everyday items left with the body. Relatively few graves contained lavish or ornate materials which suggests some people had greater status than others.

Art and Spirituality

166 WEB 166

f many figurines represent pregnant females or attributes in women related to fertility.

western and eastern Europe. Growing evidence suggests Neanderthals too were culturally sophisticated. The stimulus for the new cultural development was probably a need to represent ideas about the unknown, such as death, hunting success, and fertility, in a concrete way. A wide range of materials were used to do this. Ivory, bone, clay, and stone were used to create sculptures, and the walls of rock shelters and caves were adorned with drawings, paintings, and basrelief (sculptures that stand out slightly from the rock wall).

Key Idea: Human art and culture can be dated to as far back as 290,000 years. However a major cultural explosion took place about 35,000 years ago.

f The leaving of personal items in the grave may indicate religious or spiritual beliefs of what happens after death.

f Some archaeologists think that the first art was opportunistic. The image shown left is a drawing of a figure known as the Venus of Berekhat. It is a small statue just 3.5 cm high. It is thought a rock that looked vaguely human was used as a start and then shaped further (although this is debated). The statue is dated to about 230,000 years old.

PDBenitoJosé-Manuel 2.0SACCRama LINK 161 paintBody

f many paintings in some way represent animals that were hunted or fertility (e.g. female genitals represented as "pubic triangles").

f Similarly, rock painting may have developed from simply adorning the body with pigments. The oldest known site where ochre (a red pigment) was used is dated at 164,000 years old in South Africa.

Artistic expression of spiritual ideas

Burial

Mesolithic tomb, France (modern human)

3.0CCHitchcockDon

This Aurignacian (Upper Palaeolithic) flute, made from an animal bone, is about 43,000 years old. A similar flutelike piece of cave bear bone has been found at a Neanderthal hunting camp in Slovenia. The bone, also dated at about 43,000 years ago, suggests that Neanderthals may have made music but there is debate over the dating.

1. What evidence is there that much of the ancient art found so far had a religious or spiritual purpose?

Most Venus figurines (right) are small (approx 10 cm high) figurines of women with exaggerated breasts, buttocks, and body fat. They may have represented desirable traits among women to enhance fertility and survival.

2. What might the various Venus figurines have represented?

0 AD

5. Clearly, early humans devoted great effort to art and ceremony. How might these skills have been adaptive?

25,000 BC. Earliest ceramic art.

Earliest example of pottery. Found in Xianrendong Cave. Dated to 18,000 BC.

Venus of Berekhat, dated to 230,000 BC. The oldest known mobiliary art (figurines).

50,000 BC 25,000 BC

Oldest known parietal art (cave paintings) Cave of El Castillo, 39,000 BC.

José-Manuel Benito CC 2.5

Bhimbetka petroglyphs, India, dated to at least 290,000 BC. Consist of depressions (cupules) hammered into the rock of the Bhimbetka cave.

Bronze age begins in Europe 3200 BC

Neanderthal artists create the La Ferrassie Cave Cupules in France, dated to 60,000 BC.

3. What evidence is there that personal status may have played a part in ancient human society?

Venus of Willendor (30,000 years old)

300,000 BC 200,000 BC 100,000 BC

Ubirr rock paintings. Earliest known art in Australia (and Oceania) dated to 30,000 BC.

Neolithic era begins in Europe 4000 BC

The earliest Asian art is dated to 38,000 BC, found in the Sulawesi Cave in Indonesia.

Earliest Japanese art. 14,000 BC

Stages in art

4. The earliest examples of musical instruments are about 43,000 years old. Explain why it is likely musical instruments were probably used well before this date:

ISBN: 978-1-927309-56-8

Earliest musical instruments. There is debate over the dating of various flutes but the oldest are at least 43,000 years old.

Iron age begins in Europe 1500 BC

Earliest of the European Venus figurines (37,000 BC).

238

Earliest African art, the Venus of Tan-Tan, dated to 100,000 BC.

Photocopying Prohibited

Evolution of communication

167

Wernicke's area is part of the brain in the cerebral cortex that is linked to speech. It is involved in the comprehension of written words and spoken language. Its function becomes apparent if it is damaged. A person will then be able to speak fluently, but produce meaningless phrases.

Wernicke's and Broca's areas

Broca’s area

4.0SACCDescouensDidier

(largelyCerebellummotor control)

The hyoid bone is located in the throat and anchors the tongue muscles. The structure of the hyoid bone and its position in Homo erectus suggests that H. erectus was not able to make the same range of sounds we can. However the structure and positioning of the hyoid bone in Neanderthals suggests they probably could make a similar range of sounds to modern humans. This suggestion is supported by computer generated models based on a Neanderthal hyoid fossil.

We do not know exactly when Homo began to use language, but comparing the features associated with language in modern humans with fossils of ancient hominins can give us an idea. Cranial endocasts of Homo habilis show that the brain appears to have development in both Broca's and Wernicke's areas. However, to produce the range of sounds used by modern humans in verbal communication, the larynx and the hyoid bone must also show certain features.

Broca's area is also found in the cerebral cortex but in the frontal lobe of the brain. Broca's area is involved with the production of speech. It was discovered by Pierre Paul Broca when studying two patients who had lost the ability to speak after sustaining head injuries.

Boneclones

1. What is the function of: (a) Broca's area: (b) Wernicke's area:

2. Homo erectus probably couldn't communicate verbally in the same way as Homo sapiens, but Neanderthals probably could. Explain why:

Frontal lobe

The human brain is very large for a primate of our size, but this may not be as important as its internal organisation. The most

important specialisation of the human brain is the capacity for language. This is a result of the development of Wernicke’s and Broca’s areas. Specific differences associated with the left and right hemispheres of the brain are associated with these specialisations.

LINK 151

Controls the muscles of the lips, jaw, tongue, soft palate, and vocal cords during speech.

Wernicke’s area

The area concerned with spokenunderstandingwords.

Communication is probably the most important aspect of human cultural evolution. Humans communicate to request help, inform others, and share attitudes as a way of social bonding. The ability to accurately convey ideas to others, both in the present and future, has allowed humans to work together, often over multiple generations, to create buildings and technology, or more efficiently gather food.

Communication and Changes in the Brain

Key Idea: The human brain is characterised by a highly enlarged cerebrum and well developed areas associated with speech and comprehension of language.

Neanderthal hyoid boneAustralopithecus with brain endocast

1. The Mesolithic culture replaced the Upper Palaeolithic culture. When did the Mesolithic culture begin?

Bone fish hook: This fish hook dates from the Mesolithic period and was found in Sweden.

flint

DescouensDidier

168

Harpoon: This flat harpoon is made of bone, and dates between 12,000 and 9500 years ago. It was found in France.

Single flint blade

Sickles: These two sickles are made of flint embedded into a handle made of horn (below, right) and an antler (right). Such tools were used to cut the grasses to gather their seeds and date from the Mesolithic period.

Mesolithic Culture

DescouensDidier

WEB 168 LINK 161

Horn handle

Microlith: Made of flint or chert (a sedimentary rock). Microliths formed the points of hunting weapons such as spears. This microlith was found in the Tourasse cave, France.

Antler handle

3. Explain the significance of the warmer climate experienced during the Mesolithic period:

Tools of the Mesolithic period

Photocopying Prohibited

240

(b) How did the Mesolithic culture differ from the Upper Palaeolithic culture?

2. (a) Describe the key features that characterise the Mesolithic culture:

Three cuttingembeddedmicrolithstocreateedge

Boar Anatolia 9000 Domestic fowl Red jungle fowl Indus Valley 4000

José-Manuel Benito

Millets,

Beans, maize, peppers, squash, gourds, cotton, guinea-pigs, llamas 5000 years ago

animal

bred from the

169

groundnuts,sorghum,yams,dates,coffee,andmelons

Llama

Sandstein

Water Africa 5500

The origin of agriculture

Wild horse UkraineSouthern 6000 Arabian camel Wild camel Southern Arabia 5000 Bactrian camel Wild camel Iran 4500

Guanaco Andean plateau 6000

Lima beans, potatoes, squash,

Prohibited 241

Key Idea: The Neolithic is characterised by advances in farming and animal domestication practices, the development of crafts (e.g. pottery and weaving), the use of polished stone and flint tools, and the development of permanent Thesettlements.dateof the Neolithic (New Stone Age) culture varies with geographic location. In the middle East it dates from about 10,000 years ago, and in Europe from 4000-2000

Each domesticated was wild ancestor. The date earliest

Fertile Crescent

North China Rice and millet 7000 years ago

Photocopying

Mesoamerica

Southest Asia

Barley, wheat, Emmer, Einkorn, lentils, peas, sheep, goats, cattle 10,000 years ago

Neolithic Culture

Rice, bananas, sugar cane, citrus fruits, coconuts, soya beans, yam, millet, tea, taro, pigs

Grindstone: This Neolithic grindstone was used to grind grain so it could be used in cooking.

Neolithic people produced a wide range of purposespecific tools to harvest, store, and prepare food. The photo, above, displays food and cooking items retrieved from a Neolithic site in Europe. The containers are made of antlers and wood.

Horse

Pig

beans, and pumpkins Africa

indicates the

years ago. Domestication of animals and the development of farming allowed a shift away from the hunter-gatherer economy of the Mesolithic to a food producing culture. Not all individuals had to be involved in food gathering activities, and some people developed specialised craft skills (e.g. potters). As permanent settlements developed, ideas and knowledge could be more easily transferred between people, resulting in a rapid expansion of cultural evolution during this period.

South America

record of the domesticated form. Maize Domesticatedanimal ancestorWild Regionoriginof (yearsDateago) Dog Wolf many places? 13,000 Goat Bezoar goat Iraq 10,000 Sheep Asiatic mouflon Iran, Iraq, Levant 10,000 Cattle Aurochs Southwest Asia 10,000

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buffalo Indian wild buf falo Indus Valley 4500 Ass Wild ass Northeast

4. How did the establishment of permanent settlements influence cultural evolution during the Neolithic period?

Neolithic excavation kit: Used in the construction of massive earthworks in Britain (such as Avebury Stone Circle). The pick made from an antler was used to loosen chalk, while the ox shoulder blade was used to shovel the soft rock into a wickerwork basket.

basketWickerwork

3. Why was the shift of Neolithic people from hunter-gatherers to farmers an important step in cultural evolution?

The development of permanent settlements

Antler pick

Photocopying Prohibited

(a) In the middle East?

2. Describe the key cultural developments that characterise the Neolithic culture:

Neolithic village at Skara Brae, Scotland.

1. The Neolithic culture replaced the Mesolithic culture. When did the Neolithic culture begin

Ox bladeshouldershovel

(b) In Europe?

The development of agricultural practices significantly changed the lifestyle of Neolithic people. The huntergatherer lifestyle gave way to food production using agricultural techniques. The need to tend to crops and animals resulted in a shift away from a nomadic lifestyle to living in permanent settlements.

Skara Brae, Scotland, is the location of Europe's most complete stone-built Neolithic village (above). It consisted of ten houses, and was occupied between 3180 and 2500 years ago. The people of Skara Brae raised cattle and sheep, and may have cultivated barley. The presence of fish bones and shells amongst the ruins suggest their diet was supplemented with seafood from the nearby ocean.

http://en.wikipedia.org/wiki/File:Orkney_Skara_Brae.jpgBurka:J.FDr

Arrow head: Made of flint, this finely worked Neolithic arrow head was recovered from the Algerian Sahara desert and is about 6000 years old, it is about 3 cm long.

HINT: Oldowan, Acheulean, Mousterian, Upper Palaeolithic

Palaeolithic tool cultures

Fire, shelter, and clothing

HINT: Uses and development

What You Know So Far: Cultural Evolution170

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Photocopying

Art, spirituality, and communication

HINT: Development and art, culture, and communication. Development of the brain

NCEA Style Question: Cultural Evolution

Compare the stone tools of early species of Homo with stone tools from the Upper Palaeolithic. Discuss the developments that allowed the production of more complex tools and the effects these had on human cultural development. You may use more paper if required.

171

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1. Early Palaeolithic tool culture lasted almost 2.5 million years with only a few major developments in that time. At the beginning of the Upper Palaeolithic, about 40,000 years ago, there was a rapid expansion in the types and complexity of tools being made by humans. These represented a massive developmental leap in comparison to earlier stone tools.

A Area of the brain that allows the processing and comprehension of speech patterns

1. Test your vocabulary for this chapter by matching each term to its correct definition.

4. Homo sapiens societies changed from being hunter-gatherer societies to agricultural societies about 10,000 BC. The development of agricultural skills brought many advantages to Homo sapiens, but there were disadvantages too.

G Area of the brain that allows for the production of speech sounds by controlling the jaw, tongue, lips, and vocal cords.

2. (a) A: (c) C: (b) B: (d) D:

Describe one advantage and one disadvantage of developing an agricultural society:

A B C D

2. Identify the following tools as Oldowan, Acheulean, Mousterian, or Upper Palaeolithic:

3. Homo erectus is believed to be the first user of fire. Describe the benefit the use of fire would have had for them:

Broca's area cultural

F The change over time in accumulation of knowledge, rules, standards, skills, and mental abilities that humans use to survive.

KEYProhibitedTERMS

172

C A tool type sometimes referred to as pebble tools and associated with Homo habilis

B The carrying angle of the femur to the knee, which in humans and their ancestors brings the knee under the centre of gravity.

Wernicke'svalgusOldowanMousterianevolutiontoolstoolsanglearea

D Tear drop shaped stone tools associated with Homo erectus and archaic Homo sapiens

AND IDEAS: Cultural Evolution

Acheulean tools

E Advanced tool type associated with Neanderthals. Made by striking a flake and retouching one side of it (the Levallois method).

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1.0

Little

Modern Homo sapiens Homo sapiens erectus

Predictions made by this model

5. The amount of genetic variation within each modern human group is about the same since they have all been evolving together.

Extinct Extinct or no gene flow Little or no gene flow

African origin

1. Transitional forms would be found in only one place (in this case Africa) which is the area of origin for modern humans.

European Modern African Modern Asian Modern

Gene

African origin mya

Two primary hypotheses have been put forward to explain where modern humans evolved and what happened to the Homo species that preceded them. The multiregional

3. Today’s modern “racial” traits characteristic of a particular region can be traced back to ancient forms in that region.

4. The human species today should have a high degree of genetic diversity since it is an old species with distinct populations that have had a lot of time to accumulate genetic differences.

Multiregional model

Replacement model

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4. Humans today should have relatively little genetic diversity since the species is young.

In this model, modern Homo sapiens emerged gradually throughout the world and, as the populations dispersed, they remained in 'genetic contact'. This gene flow between neighbouring populations ensured that the general 'modern human blueprint' was adopted by all. This limited gene flow still allowed for slight anatomical differences to be retained or develop in the regional populations. This model is based largely on fossil evidence and the anatomical characteristics of modern populations, but advocates of the model maintain that the mitochondrial DNA data can be interpreted in a way that supports it.

European H. erectus African H. erectus Asian H. erectus

hypothesis proposes that modern humans evolved from Homo erectus everywhere that Homo erectus preceded them. The replacement hypothesis proposes that modern humans evolved from an African Homo erectus (via an intermediate species called Homo heidelbergensis) and replaced all other forms of Homo throughout the Old World.

Presentmya flowGene flow

European Archaic African Archaic Asian Archaic

Archaic

Key Idea: The two main contesting theories on the origin of modern humans are the multiregional hypothesis and the replacement (out-of-Africa) hypothesis.

1. Fossils that show the change from one stage to the next in all geographic regions (transitional forms).

European Archaic African Archaic Asian Archaic

Predictions made by this model

3. Modern and archaic populations should overlap in time outside the area that moderns originated (the process of replacement would not be instantaneous).

The Origin of Modern Humans

5. Today’s modern populations should differ in the amount of genetic variation, the most diversity being found in the region where moderns first evolved (this would have been the oldest group and therefore the one that had the most time for genetic variation to accumulate).

European African H. erectus Asian H. erectus

Also known as the “Out of Africa Hypothesis” and “Eve Hypothesis”. This model states that modern humans evolved from archaics in one location, Africa, and then spread, replacing the archaic populations, without interbreeding. Modern human variation is thus a relatively recent phenomenon. Mitochondrial DNA (mtDNA) analysis of modern endemic human populations showed that the highest level of genetic variation in mtDNA occurs in African populations, implying that H. sapiens arose first in Africa. Using the genetic distance between African populations and others as a measure of time, this model places the origin of modern humans at back to a single female (Eve) who lived there some 200,000 years ago.

Homo

0.5

European Modern African Modern Asian Modern

2. Modern traits should appear in the fossil record somewhat simultaneously all over the Old World range of Archaic Homo sapiens

2. Modern traits should appear first in one location (Africa) and then later elsewhere as the modern population spread to other parts of the Old World.

Diversity (0 = low)

1. State at what date the two models suggest that anatomically modern humans shared a common ancestry:

Locus (measurement) Africa Asia Europe 30 microsatellites 0.807 0.685 0.730

2. (a) Which hominin was the first to migrate out of Africa?

Diversity in the CD4 locus on chromosome 12. Blue shading represents the amount of diversity.

PalaeolithicAcheulian/Oldowan NeolithicAcheulean-like MYA Europe EastM. Africa N SE S+W Asia China 0.030.10.31.00.01

There is little doubt that humans evolved in Africa. Fossils of ancient hominins such as Australopithecus afarensis, A. africanus and Homo habilis are all found in Africa. Analysis of fossils and genetic evidence supports theories that Homo erectus migrated out of Africa about 1.8 mya. Populations of H. erectus remaining in Africa gave rise to H. heidelbergensis, which also migrated out of Africa about 650,000 years ago but remained in Europe and Western Asia. Those populations gave rise to H. neanderthalensis Homo heidelbergensis in Africa eventually gave rise to H. sapiens H sapiens began to migrate out of Africa between 120,000 and 80,000 years ago but the movement was halted by a period of cold climatic conditions. Around 60,000 years ago the final migration of modern humans out of Africa and across Europe and Asia began.

3. How many successive waves of Homo migrated out of Africa?

Analysis of various loci in the human genome show humans have very little genetic diversity. The analysis shows that outside of Africa, human genetic diversity is a sub-set of African genetic diversity.

Xq 13.3 (short arm X chromosome) 0.035 0.025 0.034

(b) At about what date did this migration occur?

(a) Describe the fate of the other human populations already inhabiting these regions, according to this theory:

(b) Identify one example of such a population:

(a) Replacement model: years ago (b) Multiregional model: years ago

5. Summarise the evidence above and decide which hypothesis it supports: multiregional or out-of-Africa:

Acheulean stone tools are found throughout Africa, Europe, and South and Western Asia, but appear to be largely absent from Eastern Asia. Tool cultures develop first in Africa then move to other parts of the world.

3.0

4. In the out of Africa model, modern humans move out of Africa to populate the rest of the world.

Evidence for dispersal

50 autosomal sequences 0.115 0.061 0.064 mtDNA control region 2.08 1.75 1.08

1. (a) the humans Australia they reached Western Europe, though Australia of

Klasies River Mouth 120,000 - 84,000 ya

even

TheagoFlores

map above and suggest why

The probable area of origin for moder n humans is south easter n Africa some 200,000 years ago Lake II 50,000 ya 130,000 ya

Afar,160,000Ethiopiaya

120,000Qafzeh-92,000 ya Skuhl 101,000 - 81,000 ya Cro-Magnon30,000ya

174 LINK 175 LINK 173 WEB 174

(b) Suggest New Zealand of

The earliest dating in East Asia for moder n humans is 67,000 years ago from Liujiang County in souther n China

Border Cave 115,000 - 62,000

248

The first moder n humans appear in Europe 40,000 - 35,000 years

before

reached

Malakunanja31,000Mungoya

The Dispersal of Modern Humans

was one

Iceland Omo

absence of ‘land bridges’ formed during the drop in sea level that occurs with the onset of glacials. Recent evidence suggests that island-hopping and coastal migration may also have been important, e.g. for the movement of people into Indonesia. The late development of boating and rafting technology slowed dispersal into Australia and the Pacific. New Zealand was one of the last places on Earth to be populated. (On the map, ya = years ago.)

Australia has been occupied for at least 50,000 years. New genomic evidence (yet to be corroborated) indicates that the ancestors of Aboriginal Australians left Africa about 24,000 years before the later migration wave that populated Asia and Europe.

Study

origin:

the last land masses populated by humans:

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Key Idea: Hominins evolved in Africa. Around 60,000 years ago Homo sapiens began the final hominin migration out of Africa, eventually reaching all parts of the world. The map below shows a suggested probable origin and dispersal of modern humans throughout the world. An African origin is almost certain, with south eastern Africa being the most likely region. The dispersal was affected at crucial stages by the last glacial, when Ice sheets covered much of Europe. Dispersal was also affected by the presence or

why

is further away from their point

fossils, at 38,000 - 13,000 years suggests there may have been waves of movement into Indonesia.

New evidence suggests first permanent Maori settlement in New Zealand only 700 years ago (not 1200 years)

Earliest moder n humans travelled across what is now the Bering Strait, via the temporary ice-age land bridge to the Americas between 20,000 and 15,000 years

The movement of humans into new parts of the world has often been cited as the major reason for the extinction of the many large animals that lived around 40,000 to 15,000 years ago, such as the woolly mammoth. The loss of megafauna is often correlated with the arrival of humans. However, other evidence suggests climate change near the end of the last glaciation was the major factor in the extinction of these animals. Also, good evidence of mammoth hunting is relatively difficult to find, suggesting humans did not play a big part in their extinction. As with many aspects of studying ancient humans, the answer is open to debate.

Polynesia populated progressively between 4500 - 700 years ago

Region covered by ice or tundra in the last ice age

A coastal Atlantic route has also been proposed for the populating of the Americas In this model, inhabitants of Wester n Europe would have travelled along the southern margins of the Atlantic sea ice to the Americas The argument is based on similarities between the Solutrean tool culture of ice age western Europe and the tool culture of the Clovis people of America (above).

2. Using examples, discuss the importance of land bridges and glaciations in the global dispersal of modern humans:

agoHawaii

The latest mtDNA analysis suggests three migrations into the Americas. The first 15,000-18,000 years ago along the western coast into South America, the second 10,000 years ago into North America, and the third 4,000 years ago along the northern coast into Greenland.

Iceland

Coastal migration / island hopping KEY

Over land migration route

WEB 175 LINK 174

Nuclear genome analysis suggests the Denisovans were a sister group to the Neanderthals. They probably shared a more recent common ancestor with Neanderthals (~300,000 years ago) than with present day humans (~400,000 years ago).

Vindija DenisovaNeanderthal MelanesianHanFrenchAfricanChinese ~40,000?Interbreedingyearsago~60,000Interbreedingyearsago

Key Idea: DNA evidence suggests that early modern humans interbred with a previously unknown Homo species. The finding of fragments of bone and teeth in a cave in Siberia indicated that another, until then unknown Homo species once

The Denisova cave, in the Altai mountains, Siberia, Russia

years~300,000~100,000interbreedingyearsagoagoyears~400,000ago

f Carbon dating estimates the age of the artefacts and bone fragment at 40,000 years.

f In 2010, a molar tooth was found at a different level to the finger bone, indicating it belonged to a different individual. A toe bone found in 2011 was at the same level as the tooth.

3. Why was the Denisovan DNA in remarkably good condition?

lived in Asia. The Denisovans, (after the cave in which the fossils were found) have yet to be assigned a species name. They are sometimes called Homo sapiens ssp. Denisova

f The molar found in the Denisova cave has unique characteristics, which are not present in the molars of Neanderthals or modern humans.

Photocopying

Possible

f In 2008, archeologists discovered a fragment of finger bone in the Denisova cave, in Siberia. The bone fragment belonged to a juvenile female (named X-woman).

Nuclear DNA analysis suggests the Denisova fossils belong to a previously unknown hominin species that existed at the same time as modern humans and Neanderthals, but was genetically distinct from them (above). The fossils are called the Denisovans, because they have not yet been formally classified.

Source:

f Fossil DNA degrades quite rapidly with increasing temperature and in acidic soil conditions. The cool temperatures within the Denisova cave preserved the DNA in the fossil fragments. The fossils contained very low levels of DNA contamination from other organisms.

Prohibited 250

2. (a) What modern human lineage appears to have interbred with the Denisovans:

1. Why are the Denisovans difficult to classify?

The Denisova cave finds

The Denisovan's interbred with the ancestors of the present day Melanesian's (right), and possibly with the Neanderthals, but not the ancestors of other present day populations, such as the Han Chinese. Melanesian DNA includes between 4% and 6% Denisovan DNA.

A Melanesian women

New Scientist 13 Aug 2011

Obersachse

f Artefacts, such as a bracelet, were found at the same level as the finger bone.

New Findings: Denisovans

175

(b) What percentage of DNA does this lineage appear to share with the Denisovans?

Using genome analysis to classify the Denisova cave fossils

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1. What percentage of Neanderthal DNA is present in modern humans?

f The DNA is often degraded to small fragments less than 200 base pairs long. This makes it difficult to obtain sequence overlaps (critical for assembly of the genome).

NIH DNA being extracted from a Neanderthal fossil

New Interpretations: The Neanderthals

176

Front Neanderthalviewskull Image: Bone clones

What has been found?

f Denisovans interbred with an unknown group of hominins, possibly an offshoot of H. erectus, about 100,000 years ago.

The Neanderthal legacy

f Samples are often contaminated with the DNA of other organisms. Between 95-99% of the DNA obtained from the Neanderthal fossils analysed was from microbes that colonised the bone after the Neanderthal died. Researchers must be careful not to contaminate the sample with their own DNA.

f The DNA is often of poor quality because it has been chemically modified and degraded by the environment.

Difficulties in analysing Neanderthal DNA

La NeanderthalFerrassieskull,France

2. In which group of modern humans is Neanderthal DNA mostly found and why?

3. Describe some possible positive and negative effects of Neanderthal DNA in modern humans:

f Some human populations that migrated east across Eurasia interbred with the Denisovans. Evidence of this in found in Melanesian DNA (see opposite).

Analysis of Neanderthal DNA published in 2016 suggests that they carried various mutations that made them up to 40% less reproductively fit than modern humans. When interbreeding occurred with humans, some of these mutations would have been passed to the human gene pool. Over time most of the harmful mutations were discarded through natural selection, but some have remained. Other genes that may have been beneficial also entered the gene pool. However the benefits that these genes once conferred may no longer exist as the human lifestyle becomes more sedentary and diets change.

f Between archaic humans and Neanderthals. Analysis in 2016 shows there may have been an interbreeding event around 100,000 years ago when an early wave of humans migrating out of Africa met a group of Neanderthals migrating from Europe to Asia.

f Between humans and Neanderthals. Analysis shows that between 1-4% of the genomes of people outside of Africa is derived from Neanderthals (more than for Africans). It is thought these encounters may have occurred as humans migrated out of Africa around 50,000 - 60,000 years ago and met Neanderthal populations already in the Middle East.

The continuing analysis of Neanderthal (and Denisovan) DNA has found that there were at least five interbreeding events between humans (H. sapiens), Neanderthals, and Denisovans.

Studies matching health problems to Neanderthal DNA have found that genetic variants inherited from Neanderthals are linked to an increase in the risk of heart attacks, depression, skin disorders, and nicotine addiction. However, the Neanderthal DNA may not necessarily be causing the health problem. It might just be associated with human DNA that is.

Key Idea: New, more complete analysis of Neanderthal DNA is revealing multiple interbreeding events with early humans. Neanderthals appeared about 400,000 years ago, and disappeared 25,000-30,000 years ago. They lived in Europe and parts of western and central Asia. Neanderthals are the

closest relative to modern humans, so there is considerable interest in mapping the Neanderthal genome. By comparing the Neanderthal genome to the genome of present-day humans, it may be possible to identify genes in modern humans that have been influenced by positive selection.

f Denisovans also interbred with Neanderthals, probably about 50,000 years ago (see opposite).

Some genes that were possibly inherited from Neanderthals or Denisovans have provided benefits. Tibetans appear to have inherited Denisovan genes that enabled high altitude adaptation. Humans may also have inherited genes associated with immunity to new diseases found outside of Africa, but already encountered by Neanderthals.

Rosino

f H. floresiensis is not a new species but instead an individual with a disease or disorder. Some scientists put forward the idea that the small skull was a result of microcephaly, a neurodevelopment disorder. Others thought that perhaps H. floresiensis suffered from congenital hypothyroidism.

The discovery of Homo floresiensis caused a storm of controversy, not helped by the fact that the specimens were removed from their repository by one palaeontologist, kept from other scientists for three months, and returned damaged. The Indonesian government also denied scientists access to the cave where the fossils were found for two years. Several hypotheses were eventually put forward to explain how such a small statured hominin evolved or survived. These included:

ScailynaCC4.0

2. Describe the different interpretations of the H. floresiensis bones:

177

Problems With Interpretation: H. floresiensis

Facial features: Relatively modern dentition, but teeth are large relative to the rest of the skull.

Key Idea: The discovery of Homo floresiensis has proved highly controversial with several hypotheses proposed to explain its position in hominin evolution. In 2003, hominin fossils, including an almost complete skeleton, were discovered on the island of Flores, Indonesia. The fossils were assigned to a new species, Homo

KNOW

3D scans withbraincortexexpansionshowedoftheprefrontalandtemporallobes,regionsassociatedcomplexthought.

No chin present.

Brain size: Very small, only 380 cc.

252

f H. floresiensis evolved a result of island dwarfism. Island dwarfism is a relatively common occurrence where large animals become smaller over time when isolated, e.g. the extinct pygmy elephants on Flores showed this adaptation.

Photocopying Prohibited

The fossils were discovered in Liang Bua, a limestone cave on Flores Island, Indonesia. The cave contains 12 m of stratified deposits. The remains of modern humans, as well as Homo floresiensis, have been found in the cave.

f Detailed examination of the bones showed no overlap with any features expected from individuals with the diseases or disorders listed above. A study of the bones and joints of the arm, shoulder, and lower limbs concluded that H. floresiensis was more similar to early humans and apes than modern humans. Small brain size coupled with more advanced brain organisation indicate possible parallel evolution of sapiens-like features.

WEB 177 LINK 149 LINK 151

Different interpretations of the fossils

ISBN: 978-1-927309-56-8

Homo floresiensis was very small and fully bipedal. Although the brain was very small, its organisation was advanced and stone tools associated with the skeleton indicated well established hunting technology. In contrast to these features, aspects of the skeleton showed primitive features found only in apes and early hominins. H. floresiensis probably lived 190,000 to 50,000 years ago. Its discovery caused widespread controversy and several opposing hypotheses were put forward to explain its place in human evolution. Since its discovery, earlier fossils dating to 700,000 years old have been found.

floresiensis, thought to have lived on the island as recently as 18,000 years ago. However, revised dates in 2016 indicate that H. floresiensis lived ~190,000-50,000 years ago. The new date is close to the time that modern humans reached the area, suggesting that encounter with H. sapiens may have contributed to the demise of the Flores population.

1. Explain the effect that the Flores finds had on the hypothesis that hominins continually evolved larger brains and bodies:

Homo sapiens

Homo floresiensis

Limestone cave formations can be dated using uranium series decay measurements. This method can be used to date calcite deposits up to the age of 300,000 years.

Rock fall from the roof of the overhanging shelter.

1. What is the significance of occupation horizons?

Skull of an early human but unable to directly determine its age.

(b) Occupation horizon A:

2. Determine the approximate date range for the items below (Hint: take into account layers/artefacts with known dates):

Dating method Dating range (years ago) Datable materials

A bison's tooth was dated at 45,000 ± 2500 years old.

Uranium series decay less than 1 million Marine carbonate, coral, shell Thermoluminescence less than 200,000 Ceramics (burnt clay)

Fission track 1000 - 100 million Volcanic rock, glass, pottery Electron spin resonance 2000 - 500,000 Bone, teeth, loess, burnt flint

Charcoal

beloEnlargedw Rock shelter used by early humans

Radiocarbon (14C) 1000 - 50,000+ Bone, shell, charcoal Potassium-argon (K/Ar) 10,000 - 100 million Volcanic rocks and minerals

(a) The skull at point B:

The remains of an ancient fireplace was dated at 18,500 ± 1000 years old.

Dating a Prehistoric Site178 LINK 179

modern human remains. It illustrates the way human activity is revealed at archaeological excavations. Occupation sites included shallow caves or rocky overhangs of limestone. The floors of these caves accumulated the debris of natural rockfalls, together with the detritus of human occupation at various layers, called occupation horizons. Accurately dating these finds is important to understanding their significance.

B A

Pottery bowl dated at 7000 ± 350 years old.

Occupation horizon A, with evidence of an ancient hearth in its uppermost layer.

Key Idea: A wide array of techniques can be used for dating artefacts, some of which show a high degree of reliability. The use of several appropriate techniques to date material improves the reliability of the date determined. The diagram below shows a rock shelter typical of those found in the Dordogne Valley of Southwest France. Such shelters have yielded a rich source of Neanderthal and

Pottery Bones Hearth Tooth

Occupation horizon B, with evidence of a human burial. Zone without any evidence of human occupation.

Charcoal fragments (possible evidence of fire use and excellent for radiocarbon dating).

3. Which dating method or methods could have been used to date each of the following, at the site on the previous page:

The reconstruction of a dig site, pictured above, illustrates some of the features that may be present at a site of hominin activity. Naturally, the type of information recovered from a site will depend on several factors, including the original nature of the site and its contents, the past and recent site environment, and earlier disturbance by people or animals. During its period of occupation, a site represents an interplay between additive and subtractive processes; building vs destruction, growth vs decay. Organic matter decays, and other features of the site, such as tools, can be disarranged, weathered, or broken down. The archaeologists goal is to maximise the recovery of information, and recent trends have been to excavate and process artifacts immediately, and sometimes to leave part of the site intact so that future work, perhaps involving better methodologies, is still possible.

Human skull

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5. Outline the importance of involving several scientific disciplines when interpreting a site of hominin activity:

Excavationquestion.through rock strata (layers). The individual layers can be dated using both chronometric (absolute) and relative dating methods.

Searching for ancient human remains, including the evidence of culture, is the work of palaeoanthropologists. Organic materials, such as bones and teeth, are examined and analysed by physical anthropologists, while cultural materials, such as tools, weapons, shelters, and artworks, are examined by archaeologists. Both these disciplines, palaeoanthropology and archaeology, are closely associated with other scientific disciplines, including geochemistry (for chronometric dates), geology (for reconstructions of past physical landscapes), and palaeontology (for knowledge of the past species assemblages).

Interpreting Fossil Sites

(b) Skull: (d) Tooth:

Stone tools

istock

4. Explain why palaeoanthropologists date and interpret all of the remains at a particular site of interest (e.g. animal bones, pollen, and vegetation, as well as hominin remains):

RAPhoto:

Bones from a large mammal with evidence of butchering (cut and scrape marks from stone tools). These provide information on the past ecology and environment of the hominins in

(a) Pottery bowl:

Key Idea: The discovery of Homo naledi presents problems. The placement of the bones appears deliberate, which seems unlikely for an ancient hominin, and they are difficult to date because there are no dateable sediments around them.

Superman's crawl may have been higher in the past, allowing easier access.

2. Describe two reasons why dating the H. naledi bones is difficult:

f Dating the Homo naledi bones is problematic because they were found deep in the cave. Ordinarily, fossils can be dated by relative dating. Other fossils in the sediment can be used to date the unknown fossils. For example, if the bones of a predator species of a known age had been found in the cave, then it may imply that H. naledi lived at the same time. However, only H. naledi bones have been found, expect for a few small birds on the surface. Radiocarbon dating cannot be used because it only dates accurately to 50,000 years of age and H. naledi is likely to be much older than that.

f Various anatomical ways of dating the fossils have been tried, such as measuring parts of the skull and teeth and comparing them to other hominin fossils. These techniques have put the age of the bones at ~1-3 million years old.

179

4.0CCBergerRLee WEB 179

Problems with Dating: H. naledi

dozens of teeth. Interestingly, no other types of animal or plant have been found in the cave and there is no indication of water flowing in the past. This has led the investigators to hypothesise that the bodies were deliberately placed there by other Homo naledi. Also the lack of other flora or fauna and sediments (other than cave dust) has made it very difficult to date the fossils. They have both advanced and primitive features, which some think puts them at the cusp of the transition between Australopithecus and Homo

Fossil find

f If the bones had been washed into the cave by a river system it may have been possible to use the sediments deposited or other bones that had been washed in to provide a date. The excavation team has yet to find any evidence of a river or water flow. One other way of dating the bones is by dating the flowstones found in the cave. Flowstones are sheets of calcium carbonate built up by water flowing down cave walls (similar to stalactites). However the flowstones do not cover much of the cave floor and fossils.

Cave entrance

Dating Homo naledi

Superman’s crawl (less than 25 cm high) 10 metres 978-1-927309-56-8

Bodies were probably dropped down the shaft over a long period of time (maybe centuries)

1. Describe one of the problems in explaining the deliberate placement Homo naldei bones in the Dinaledi chamber.

Dragon’s back

In 2013 two cavers exploring the Rising Star cave system near Johannesburg in South Africa found a passage that led to a chamber containing the bones of a new hominin species. Excavation has found more than 1500 specimens from at least 15 individuals including ribs, skulls, jaws, and

Dinaledi chamber

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The Rising Star cave system

New finds and controversies

180

What You Know So Far: Patterns of Dispersal

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HINT: Out-of-Africa or multiregional? Evidence for each.

The origins of humans

HINT: Interpretations of new finds and their significance.

REVISE 256

• discuss how the data supports (or does not support) the models above You may use more paper if required.

Style Question: Patterns of Dispersal

1. Two important models for human dispersal are the out-of Africa model and the multiregional model.

181

African origin

AfricaEurope Asia

Evidence from stone tools suggests Homo erectus reached China 1.27 million years ago. The most recent fossil finds suggest it remained there until 143,000 years ago.

Analysis of mitochondrial DNA shows there are 6 different groups within the human population. Only one of these groups, L3, is found outside of Africa. L3 is believed to have arisen about 100,000 years ago.

African origin

• explain what the data above suggests about the dispersal of the genus Homo

Multiregional model

• describe the out-of-Africa and muliregional models

AfricaEurope Asia

Discuss which of the models for human dispersal (shown above) the data support. In your answer you should:

Out-of-Africa model

Analysis of DNA from the Y chromosome indicates that all living males today are related to a man that lived between 140,000 and 500,000 years ago, probably in Africa.

A Summary of Trends in Hominin Evolution

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Millions of years ago 3

Key Idea: Specific trends can be seen in human physical (biological) and cultural evolution. Use this activity to revise your knowledge about trends in human evolution. Cut out the images on page 259 and place them in their correct place on the timeline of human evolution

Skull and body features

(below and on page 261). Add notes about significant developments and trends. Notes may include information about the tool technology (including the main user of the tool), skull features and brain size, bipedalism, how food and diet influenced dentition, and hominin distribution.

182

Jaw andBrainshapesizefeaturesTools 2

259 © 1988-2016 BIOZONE International ISBN: 978-1-927309-56-8 Photocopying Prohibited Australopithecusafarensis neanderthalensisHomo Homo sapiens Homo habilis Homo erectus heidelbergensisHomo Mean457volumebraincm3 Mean552volumebraincm3 Mean1016volumebraincm3Meanbrainvolume1512cm3 Mean1335volumebraincm3 Mean1250volumebraincm3

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Many argue that now, with the ability to extract DNA from fossils and to clone animals, some of the animals that were exterminated by humanity should be returned to the world (de-extinction). There has been only one case of de-extinction. The Pyrenean ibex was a subspecies of Spanish ibex. It became extinct in 2000. Scientists used DNA from the last female to create 285 cloned embryos that were implanted into Spanish ibex. In July 2003, one clone survived to birth, but died after only a few minutes due to lung defects.

• Justify your opinion on whether restoring extinct organisms is a possibility.

Extinction is part of the evolution of life. The loss of an organism leaves a vacant niche and provides the opportunity for another organism to evolve into that ecological space. The rate of natural (or background) extinction is about 0.1 species per million years. The extinction rate over the last 400 years is estimated to be around 1000 times greater than this. This is because human activity since 1600 AD has directly or indirectly caused the extinction of over 400 known species. These include the dodo, the moa, the Tasmanian tiger, and more.

Many organisms on the brink of extinction are now having DNA, sperm, and egg samples cryogenically frozen to preserve them in the event of their extinction in the near future. The hope is that technology will enable the organism to be cloned and so return to the world in the future.

Technology has now developed to the point that DNA can be extracted from the 30,000 year old bones of Neanderthals. Technology also now enables animals to be routinely cloned.

1. Analyse the information provided and integrate it with your biological knowledge to discuss:

Scholarship Question: Return of the Dodo183

Could species become de-extinct?

solitaire (extinct)

• The evolutionary and ecological factors that contribute to declining populations and increasing rates of extinction. Use examples to support your discussion.

The flightless dodo stood about 1 metre tall and weighed between 10 and 20 kilograms. Only one egg exists and its authenticity is in dispute. The dodo egg, apparently, is larger than an ostrich egg.

TEST 262

You may use extra paper if needed.

Dodo (extinct)

4.0CCFischerPatrickJ.

Victoria crownedNicobarpigeonpigeonRodrigues

The dodo (Raphus cucullatus) is a possible candidate for de-extinction. Endemic to the island of Mauritius, the dodo was first recorded in 1598 and was exterminated by 1662 so completely that only one complete skeleton exists and no complete specimen is known. Scientists are not even sure what the dodo looked like because of the variation in sketches by 17th century artists. However enough DNA has been extracted from bone that the genetic relationship of the dodo to other birds has been identified.

The Nicobar pigeon measures about 40 cm long and weighs about 500 grams. It lives in coastal regions of Andaman and Nicobar Islands, India. Its egg is about the size of a chicken's egg.

Tooth-billed pigeon

Phylogeny of the dodo

• How humans could manipulate the transfer of dodo DNA to restore a population of dodos to Mauritius and the possible biological implications of doing this.

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264

The three-spine stickleback (Gasterosteus aculeatus) are freshwater fish found above 30° north in marine and freshwater environments. It has been the subject of many scientific studies for many reasons including its breeding behaviour, varied morphology, and population genetics. The three spined-stickleback may be anadromous, migrating from the sea to lakes or they may be entirely restricted to fresh water.

Studies of these two forms from the five different British Columbia lakes have found the following:

f A benthic form will display to benthic forms of stickleback from Japan.

f Experiments into the selection factors in the three-spined stickleback bred limnetic forms with benthic forms by artificially fertilising eggs from one form with sperm from another (and vice-versa), producing a population of hybrid fish. The fish were introduced into an artificial pond and left to interbreed. Measurements and observation of the second generation of hybrids were then taken. It was found that the second generation (F2) hybrids were sorting into benthic and limnetic niches. Those fish that were at the extremes of this sorting (they spent all their time either feeding on free swimming prey or bottom dwelling prey) grew faster than those that ate a mixture of prey.

Year Total fish in sample Frequency of benthics Frequency of limnetics Frequency of F2 hybrids

1 1057 0.50 0.48 0.019

TEST 266

• A justified history of the formation of the benthic and limnetic forms

f The two forms never mate with each other.

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Scholarship Question: Stickleback Speciation

f Mitochondrial DNA analysis shows that the benthic and limnetic forms in each lake are more closely related to each other than to sticklebacks in other lakes.

f The benthic forms in one lake will spawn successfully with the benthic forms in another lake, and the limnetic forms in one lake will spawn successfully with the limnetic forms in another lake.

f Sampling of the lakes over three years produced frequencies of three forms of stickleback:

• Evidence for and against speciation

2 962 0.50 0.49 0.010 3 994 0.49 0.49 0.014

1. Analyse the information presented. Justify whether the benthic and limnetic forms are separate species and establish a justified speciation history of the three-spined stickle back. Your justification should include:

184

f Analysis of nuclear DNA shows the limnetic forms in all 5 lakes are more related to each other (and marine lineages) than to benthic forms.

Speciation in three-spined sticklebacks

In British Columbia (Canada) there are a five lakes that contain two forms of stickleback (known as stickleback species pairs). They remain in the lake throughout their life cycles. There is a limnetic form that lives in the shallows and feeds on free-swimming plankton and a benthic form that lives deeper in the lake and feeds on prey in the lake sediment.

• Factors that influence speciation

268

The birth weights for 100 babies are displayed

Draw: Represent by means of pencil lines. Add labels unless told not to do so.

Describe: Define, name, draw annotated diagrams, give characteristics of, or an account of.

Explain: Provide a reason as to how or why something occurs.

Illustrate: Give concrete examples. Explain clearly by using comparisons or examples.

Interpret: Comment upon, give examples, describe relationships. Describe, then evaluate.

Birth weight data for activity 85

Derive: Manipulate a mathematical equation to give a new equation or result.

Define: Give the precise meaning of a word or phrase as concisely as possible.

Annotate: Add brief notes to a diagram, drawing or graph.

Suggest: Propose a hypothesis or other possible explanation.

Apply: Use an idea, equation, principle, theory, or law in a new situation.

Calculate: Find an answer using mathematical methods. Show the working unless instructed not to.

Compare: Give an account of similarities between two or more items, referring to both (or all) of them throughout.

3.4303.2601.4953.6903.3803.3504.5604.0504.7103.8403.9703.8303.0903.1353.2204.1003.2603.4003.1303.8253.4003.7704.4004.1703.8004.5103.2603.7803.3502.9803.9552.6403.8103.6303.8403.3752.6603.3803.4003.1502.6603.5704.1803.9101.5603.6303.0953.5303.8303.740below.

Evaluate: Assess the implications and limitations.

Summarise: Give a brief, condensed account. Include conclusions and avoid unnecessary details.

Measure: Find a value for a quantity.

Solve: Obtain an answer using numerical methods.

State: Give a specific name, value, or other answer. No supporting argument or calculation is necessary.

Design: Produce a plan, object, simulation or model.

2.7153.0703.5502.9803.9702.3503.3003.1603.0304.3004.0502.8003.2303.0004.0823.7404.0602.8604.2204.0503.5502.6404.4903.8001.9704.1102.8602.3903.8001.9503.4002.7703.0603.7903.1054.0502.0403.9153.9703.3503.0302.6203.7903.2303.3153.2603.6203.5703.2303.510

Appendix

Predict: Give an expected result.

Identify: Find an answer from a number of possibilities.

Contrast: Show differences. Set in opposition.

The following terms are often used when asking questions in examinations and assessments.

Determine: Find the only possible answer.

Questioning terms in biology

Construct: Represent or develop in graphical form.

Discuss: Show understanding by linking ideas. Where necessary, justify, relate, evaluate, compare and contrast, or analyse.

Distinguish: Give the difference(s) between two or more items.

List: Give a sequence of answers with no elaboration.

Estimate: Find an approximate value for an unknown quantity, based on the information provided and application of scientific knowledge.

Outline: Give a brief account or summary. Include essential information only.

Analyse: Interpret data to reach stated conclusions.

CDC: Centers for Diseases Control and prevention, Atlanta, USA, DoC: Department of Conservation (NZ), DoC-KW: K Walker, DoC-RM: Rod Morris, DoC-VV: V. Vercoe, F&B: Forest and Bird Society (NZ), LBS: Lissa Bainbridge-Smith, MM: Mike Meads, NASA: National Aeronautics and Space Administration, NIH: National Institute for Health, NOAA: National Oceanic and Atmospheric Administration, RA: Richard Allan, TM: Tracy Montford, USDA: United States Department of Agriculture.

• Cereal Research Centre, AAFC for their photograph of a pheromone trap • Rogan Colbourne for his photograph of North Island kokako • Scott McDougall for the photographs of New Zealand falcon and the pukeko with chick • Andrew Dunn for the banded snail photographs • Alex Wild for his photograph of swollen thorn Acacia • Missouri Botanical Gardens for their photograph of egg mimicry in Passiflora • California Academy of Sciences for the photo of the ground finch • Mike Meads for the use of his excellent photographs of the Superb and Gillies giant land snails • Rocky Mountain Laboratories, NIAID, NIH • The late Dr. M Soper, for his photograph of the waxeye • Tony Northrup for the photo of the chimpanzee • www.skullsunlimited. com for some of the hominin skulls • Grotte de Rouffignac, for drawings and photographs of the Rouffignac Cave • April Nobile www.AntWeb.org for the photo of the slavemaker ant • Landcare research for the photo of the German wasp • Peter Bray, Airborne Honey Ltd for the picture of anal tubes of beech scale insects • C.R. Veitch, DoC for short-tailed bat photo • J. Barkle, DoC for photo of Dactylanthus taylorii • Jenny Ladley (University of Canterbury) for the photographs of the tui and the bellbird in mistletoe • Professor Jeff Podos, Biology Department, University of Massachusetts Amherst for his photographs of Galápagos finches • Melicytus photos were generously supplied by John Barkle, Jeremy Rolfe, Melissa Hutchinson, and Bruce Clarkson. We are also grateful to Rewi Elliot and the NZ Plant Conservation Network for helping to obtain the Melicytus images.

We acknowledge the generosity of the following individuals and organisations who have provided photographs for this edition:

• AKA • Bjorn Christian Torrissen • Alvesgaspar • Stan Shebs • Kristian Peters • Orikirin 1998 • Lazaregagnidze • Chriwick Chap • Tangopaso • Melodi2 • Coolstock • Thergothon • Heuchera • Michael (inski) • Rudolph89 • Brocken Inaglory • Brian Gratwicke • Artfarmer • Greg Hume at en.wikipedia • ATamari • Adrian A. Smith • Kalyan Varma • Alex Wild • Karora • Graham Collins • Onno Zweers • flowergarden@noaa.gov • small • Charlesjsharp • Snake3yes • Jo Naylor • it:Utente:Cits • Art G • Rosino • Olaf Leillinger • Omasz G. Sienicki • JM Garg • David M. Green • Bruce Marlin • Lorax • Kirt L Onthank • Taollan82 • Velela • Duncan Wright • Bjorn schultz • Xiangyux • Emw • Ghedoghedo • Petit Deuxmont • Matt Binns • Didier Descouens • Guerin Nicolas • Ji-Elle • Brett Eloff • José-Manuel Benito • Don Hitchcock • Sandstein • Dr. John F. Burka • Obersachse • Lee R Berger • J Patrick Fischer

Photo Credits

Contributors identified by coded credits are:

We also acknowledge the photographers that have made their images available through Wikimedia Commons under Creative Commons Licences 2.0, 2.5., 3.0, or 4.0:

We acknowledge our use of royalty-free images, purchased by BIOZONE International Ltd from the following sources: iStock images, Dollar Photo Club, Corel Corporation from various titles in their Professional Photos CD-ROM collection; IMSI (International Microcomputer Software Inc.) images from IMSI’s MasterClips® and MasterPhotosTM Collection, 1895 Francisco Blvd. East, San Rafael, CA 94901-5506, USA; ©1996 Digital Stock, Medicine and Health Care collection; ©Hemera Technologies Inc, 1997-2001; © 2005 JupiterImages Corporation www.clipart.com; ©1994., ©Digital Vision; Gazelle Technologies Inc.; ©1994-1996 Education Interactive Imaging (UK), PhotoDisc®, Inc. USA, www.photodisc.com; Bone clones for some skull images. We also acknowledge the following clipart providers: TechPool Studios, for their clipart collection of human anatomy: Copyright ©1994, TechPool Studios Corp. USA (some of these images have been modified); Totem Graphics, for clipart; Corel Corporation, for vector art from the Corel MEGAGALLERY collection.

Animal communication 65-67

Foraging, cooperative 77

- and New Zealand speciation 157-161

Genetic bottleneck 113

Courtship Crepuscular90-91activity 38

- H. floresiensis 206-207, 224, 252

- H. heidelbergensis 206-207, 225

Adaptation 114

Annual rhythms 33

Cave painting 237-238

- New Zealand invertebrates 157-159

Gene flow 111

Behaviour, record 68

Genetic code 168

AuxinAutopolyploidy206-20713624-25

Balanced polymorphism 107 Behaviour 3, 68-78

Geological history, New Zealand 155-156

Gradualism 154

Harmful mutation 104, 106-107

- H. antecessor 206, 225

- A. garhi 206

Fossil record 173

Human biological clock 34

Eukarya, domain 169 Eusocial 70

Exploitation 52, 58

Attack behaviour, cooperative 76 Australopithecus 204, 220-221

- H. erectus 204, 206-207, 209, 212, 224

Agriculture, and human evolution 241 Agriculture, development of 231

Art, and human evolution 237-238

Circadian rhythms 36, 38

Acheulean tools 232

B Bacteria, domain 168

- Hebe 164 - horses 176 - human trends 204-205

Fruit fall 44

Genetic drift 111, 113

Habitat isolation 128

- H. ergaster 206-207, 223

Cultural evolution 230-242 Cytochrome c 189

Exogenous rhythm 36

Bipedalism, in hominins 215-217

Hierarchies 78, 80, 82, 84, 85

Colonisers, oceanic island 179-180

Fitness 90, 103, 114

Homo 204-205, 222-226, 251-252, 255

Behavioural isolation 129

Biological species 125

- A. bahrelghazali 206

- A. afarensis 204, 206-207, 209, 212, 218, 220

Chloroplasts, origin 168

Circatidal rhythm 36

Gravitropism 23, 25-26

Founder effect 113

Circannual rhythm 36

- H. naledi 206, 255

Herbivory Heterozygous52 advantage 107

Allelopathy 22

- A. africanus 206-207, 221

Gene duplication 109-110

Fossils, role in dating 173, 253-255

Homing behaviour 20-21

Homologous proteins 187-188

- H. rudolfensis 206

Horse evolution 176

- Ar. ramidus 206-207, 213-214, 219

Common ancestor 145 Communication methods 66 Communication 65-67 - bees 18 - evolution of 239 - pheromones 9 Competition 52, 59-60 - intraspecific 80

Adaptive radiation 150-151, 185 - Darwin's finches 180 - Hebe 164 - ratites 152 - wrens

Brain, volume of hominins 210-211

Aggressive162-163behaviour 78

Biogeography 178

- H. georgicus 206, 223

Homologous structure 185

Adaptations-forbipedalism 216-217

Index

Altruistic behaviour 71-72

Hebe evolution 164

Homology, DNA 190

- NZ parrots 114

Absolute dating 253

- A. sediba

Haemoglobin mutation 106-107

Biological rhythms 36-40 - human 39-40

Hominini 200

Beneficial mutation 104-105

Genetic variation 111

Brood parasites 92

Circalunar rhythm 36

Food gathering, cooperative 77

Brain, human 239

- Ar. kadabba 206

Home range 86-88

Foraging, ants 18

Conserved protein 187

Denisovan hominin 206, 225, 250 Dentition, trends in human 212 Developmental biology 191 Diastema 202

Continental drift, and evolution 181 Convergent evolution 146-147

Actograms 41-43

Astronomical cycles 33

Carrying angle 216

Evolutionary processes 111

Geographical isolation 128, 132

Genotype Geographical103barriers 128,132

- A. anamensis 206

Archaea, domain 169 Archaeopteryx 175 Ardipithecus 220-221

Breeding behaviour 90-91

Classification, primates 200 Clothing, and human evolution 236 Coevolution 148

Darwin's finches - adaptive radiation 180 - natural selection 118-119 Dating methods 253-254 Dating, relative 173 Day length, plant responses to 47 Defensive behaviour, cooperative 75 Denisova cave 250

Galápagos islands 179-180

Allopolyploidy 136, 138-140

Analogous structures 146

Gondwana 155

- New Zealand parrots 160-161

Hominoid definition 200 Hominoidea 200

Gamete isolation 129

Homology, anatomical 185

- H. neanderthalensis 205-207, 209, 226, 251

A Abscission 44

Animal behaviour record 68

Free-running period 41, 43

Fixed action pattern 65

Directional selection 115, 117-118 Dispersal 11

Activity patterns 41-43

Gause's competitive exclusion principle 59

Genetic switches 192

- novel forms 192 - rate of change 154 - whales 177, 186

Circadian rhythms, NZ birds 38

D Daily rhythms, humans 39 Daily rhythms, plants 45

- H. habilis 204, 206-207, 209, 212, 222

Agonistic behaviour 78

- H. sapiens 205-207, 209, 212, 226

Homology, protein 187-188

Foramen magnum 208

Embryological evidence, for evolution 191 Endogenous rhythm 34-35 Endogenous rhythm 36, 39 Entrainment 35, 43 Environmental cue 34 Ethogram 67

Evo-devo 192 Evolution 111 - and continental drift 181 - and gene duplication 109-110 - convergent 146-147

Facultative mutualism 55

Broca's area, in human speech 239

Fire, use of 235

- cultural 230-242 - Darwin's finches 118-119, 180 - divergent 145 - evidence for 170

Allopatric speciation 132, 135

Fossil 171-172

Activity patterns, types 38

Dispersal patterns, human 248-249 Disruptive selection 115, 119 Diurnal activity 38 Divergent evolution 145 Divergent evolution, ratites 152 DNA hybridisation 190 DNA, and human evolution 250-251 Dominance hierarchies 78, 82, 84, 85 Dormancy, plants 44

Breeding territories 95

Biological clocks 34-35

Hominin definition 200 Hominin features 219-226

Ecological isolation 128

External cue 36

Fossil, transitional 175-177

Hominidae 200

Adaptive behaviour 3

Cooperative behaviour 71-77 Core area 86

Conflict behaviour 78

Strata, rock 173

Hybrid sterility 131

Human dispersal, evidence 247

Human birth weight, stabilising selection 116

Reproductive strategies 92 Rhythms, plant 44-45

Novel forms, evolution of 192

Phytochrome 46

Prezygotic isolating mechanism 128-129

Transitional fossil, horse 176 Transitional fossil, whale 177 Trilobite, as index fossils 172 Tropism 3, 22-26

T Taxes 3, 7

Index fossil, use in dating 172

Melatonin, role in sleep 34

Mousterian tools 232

Oldowan tools 232

Mating systems 94

Silent mutation 104

Interspecific competition 59-60

Stasis 154 Stimuli 4 Stone age tools 232-234

Human brain 239

New Zealand birds - adaptation 114 - competition 59 - migration 14, 17 - speciation 145, 160, 162

Niche differentiation 59, 138 Nocturnal activity 38 Non-disjunction 137

Hylobatidae 200

Natural selection 107, 111, 115-120

Isolating mechanisms 128-132

Human skull 203

Reproductive isolation 132, 138

Monogamy 94

Occupation horizon 253 Oceanic island colonisers 179-180

Molecular clock hypothesis 189

Short-day plants 47

N Nakedness, human evolution 216

Pukeko communication 67 Punctuated equilibrium 154

Sickle cell disease 106-107

Hybrid inviability 131

- by polyploidy 136, 140-141 - in New Zealand 145, 157-164 - sympatric 138-140

Timing behaviour 3

New Zealand, geological history 155-156 New Zealand, speciation 157-161

Orientation behaviour 3-5, 7, 22-26 - round dance 77

Magnetic compass navigation 15 Malaria, and heterozygous advantage 107 Mammals, adaptive radiation in 150-151

Tools, in human evolution 232-234

Instant speciation 138-140

U Upper Palaeolithic tools 232

Hybrid breakdown 131

Photoperiodism, in plants 46-47 Phototropism 23-24

Models of human evolution 246-247

Seed germination 44

Modern human 205-207, 209, 212, 226 - dispersal patterns 248-249

Mechanical isolation 129 Meiosis, non-disjunction 137

Parrots, New Zealand 114, 160

Pentadactyl limb 185

Paranthropus aethiopicus 206 Paranthropus boisei 206-207, 212, 221 Paranthropus robustus 206-207, 222 Parasitism 52, 54

Parental care 92, 94

Shelters, human use 236

Waggle dance, bee navigation 18 Wernicke's area 239 Whale evolution 177, 186

Kin selection 71-73

Woodlouse behaviour 5

Zeitgeber 35, 43

Klinokinesis 5 Klinotaxis 7

Skull, human 203

Phyletic gradualism 154 Phylogenetics 168 Phylogeny, human evolution 206-207

Multiregional model, human evolution 246

Peppered moths, directional selection 117 Phase shift 41 Phenotype Pheromones1037, 9

Population change 111

Wren, adaptive radiation 162-163

Selection pressure 103

Polyploidy 136, 138 - in Melicytus 139 - in speciation 136, 138, 140-141

Stabilising selection 115-116, 120

Replacement model, human evolution 247 Reproductive effort 92-93

XYZ

Human evolution 204-207 - agriculture 241 - bipedalism 215-217

Transitional fossil 175-177

New Zealand plants - polyploidy 139 - speciation 139, 164

Postzygotic isolating mechanisms 131 Predation 52, 58

Intraspecific competition 80

Mitochondria,14-17origin 168

Neolithic culture 241-242

Primate, skull features 202-203

Social behaviour and survival 73-74

Star compass navigation 15

Sleep movements, plants 28, 45

Nastic response 3, 22, 27-28

Mesolithic culture 240 Migration 10-17, 111 - birds

Neanderthals 205-207, 209, 226, 251

Ring species 126-127

Molecular phylogenetics 168

Obligatory mutualism 55

Wheat, speciation 136, 140-141

Modularity, and evolution of body forms 192

Social groups, types 69 Social organisation 70

Temporal isolation 128 Territories 80, 86, 89, 95

Melicytus , evolution in 139

Reproductive isolating mechanisms 128-131

Kenyanthropus platyops 206

Species formation, stages in 135 Species interactions 3, 52-61

Orrorin tugenensis 206-207 Orthokinesis 5 Out of Africa hypothesis, human evolution 247

Innate response 3

Protein, conserved 189

Presocial species 70

Primate characteristics 198, 201-202

JK Jet lag 35

Species, definition 125 Species, Canis 125

Plant hormones 24-25 - in timing responses 44 Plant responses 22 Plant rhythms 22, 44-45 Polyandry 94 Polygny Polygynandry94 94

Protein homology 187-188

Rising Star Cave 255 Round dance, bee navigation 18

Spirituality, and human evolution 237-238

Relative dating 173, 254

Primate hand 201

Mutation Mutualism11152, 54-57

Mobbing behaviour 71

Hybridisation, Melicytus 139 Hybridisation, wheat 136, 140-141

Primate classification 200

Ratites, adaptive radiation 152

Skeleton, adaptations for bipedalism 216-218

- competing models 246-247 - nakedness 216 - permanent settlement 242

Kineses 3, 5-6

Saddlebacks, speciation in 145 Sahelanthropus tchadensis 206

Kea-adaptation 114 - origin 160

- primate features 202-203 - trends 208-209

Skin colour, humans 120

Stratification 44 Sun compass navigation 15 Symbiosis 52 Sympatric speciation 138-140

Palaeolithic tools 232-234

Neanderthal interbreeding 251

L Lek system 95 Long-day plant 47 Lucy, skeleton 218

Mutation 104-108

Neanderthal burial 237

Valgus angle 216 Variation , defined 103 Vernalisation 44 Vestigial structure 186

Kaka-adaptation 114 - origin 160

Speciation, defined 132 - allopatric 132-135

Navigation 3 - in ants 18 - in bees 18 - in salmon 21 - mechanisms 15 - migratory birds 14-17