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NEWER
SCIENTIST
The Theory of Evolution
Issue#12, June 2016
By Lewis Thompson
CONTENTS BIOLOGICAL EVOLUTION THE FOSSIL RECORD Source: http://darwinandthegalapagos.weebly.com/uploads/5/3/6/8/53683367/39624 71_orig.jpg
Ever wondered where did the multitude of species on earth come from and why they are different and unique? Scientists, particularly Biologists, and those concerned with cells, organisms, genetics and the like, as well as Paleontologists and Geologists all support the view that all living things on earth, organisms or species, including the human race have evolved over thousands, if not millions of years to resemble what they look like and behave like today. All species or populations are the result biological evolution. “… the theory of evolution is supported by so many observations and confirming experiments that scientists are confident that the basic components of the theory will not be overturned by new evidence. However, like all scientific theories, the theory of evolution is subject to continuing refinement as new areas of science emerge or as new technologies enable observations and experiments that were not possible previously.”
DATING METHODS • Sedimentary Rock • Carbon & Radiometric Dating • Dendrochronology • Molecular Clock NATURAL SELECTION SPECIATION EVOLUTIONARY THEORY IS ACCURATE CASE STUDY: Human Evolution
Source: http://www.nas.edu/evolution/TheoryOrFact.html
Biological Evolution From a scientific basis, evolution is referred to as a process by which many different and varied kinds of living organisms are thought to have originated and advanced from earlier forms during the long history of the earth. More specifically, biological evolution is any type of genetic modifications in a species or population that is passed down and inherited over a series of generations. The modifications or changes in the population can and may either be minute or large, easy to see or not very easy to pick up. In order for an event to be classified as an instance of evolution, changes have to happen on the genetic level of a species or population and be handed on from one generation to the next generation and so on. These sorts of modifications become visibly evident in the physical traits (phenotypes) of the species or population.
Paleontologists play a crucial role in the theory of evolution because they study and scrutinize the history of life on earth, and all living things whether they be still living and evolving or are extinct, based on the fossils. Fossils are the remains of organisms or species that have been found preserved in rock or have become a rock like substance. Sedimentary rock unlocks many questions concerning the evolution of living things because it is home to fossils, and it too has developed over time, thousands and hundreds of thousands of years, in layers. It is between these layers that the remains of once living organisms have become trapped and forever bonded in and with the history of the earth.
The Fossil Record RecordRecord Paleontologists, Geologists and Biologists all become inter-connected in the Theory of Evolution through the relationship between rocks, fossils and organisms. The fossil record is evidence of how species have changed and evolved throughout the history of the earth. More specifically, only fossils of single cell organisms have been unearthed in rocks that are dated more than a billion years old. Two-celled or a few multi-celled organisms have been found fossilized in rock material that is approximately 600 million years old. Fossils of unusual fish creatures, without any jawbone structure, have been discovered in rock material that dates around 500 million years old. Over the next 100 million years fish continue to evolve and develop jaw structures. With evolution being an extremely slow and gradual process amphibians do not appear fossilized in rock until about 350 million years ago. The fossils of reptiles make their appearance approximately 300 million years ago. The oldest fossils of mammals are found in rock dated 230 million years ago. It is in sedimentary rock dated to be approximately 150 million years old that the first fossils of birds are discovered. Although the fossil record does not definitively provide evidence of every single organism or plant and animal species that ever inhabited earth, it does furnish scientists with a multitude of evidence that substantiates and gives credibility to all life and species.
Source: https://s-media-cacheak0.pinimg.com/736x/38/ff/30/38ff30c59 b16e2ad197b8a1b2b9b8f4b.jpg
Dating Methods A variety of dating methods are utilized by scientists to interpret the fossil record: Sedimentary rock dating; carbon dating; radiometric dating; dendrochronology; and the molecular clock. SE DIME N TA R Y RO CK
Because sedimentary rock has been formed in layers built up over a long time, it is obvious that when looking at a cross-section of the rock that the older layers of sediments were laid down first therefore the oldest rock is at the bottom and the newer younger layers of rock are on top. If any living organism became entombed in the rock layer at the time it was laid down, then in all likelihood it would be approximately the same age as the rock that surrounds it, therefore it can be dated. However, some caution needs to be taken with this method of dating as the plates in which this rock resides are movable and therefore it is feasible that the layer or layers of sedimentary rock embodying the fossils could have been propelled upwards by a force that resulted in it forming a fold, or even causing it to break or relocate in converse vertical directions to manifest itself as a fault line. CA RBO N & RA DIOM ETR IC DA TIN G
Geologists, since the 1950s have used radioactive elements and impurities within the earth’s rock structures to determine the absolute age of rocks, how long ago they were formed and from this technique they can determine the age of the fossils within them. A type of radiometric dating is carbon dating. This type of dating is employed to ascertain the age of fossils, biological remains, because all living things contain carbon-12 and a small amount of carbon-14. However, carbon-14 is unstable and after an organism dies it decays and forms nitrogen but the carbon-12 remains stable. Therefore the ration of carbon-14 to carbon-12 decreases gradually over time and it by measuring this ratio that the age of a fossil can be determined. However, it can only be determined up to 60,000 years old because after this time there is no or a negligible carbon-14 present.
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DE N DR OCHR ON O LO GY or tree-dating
based on the analysis of patterns of tree rings known as growth rings has been recognized as a scientific technique since the early 20th Century. This technique allows for the matching up of the same species of trees that have been subject to the same environment and the same conditions. THE M OL ECU L AR CLO CK
The Molecular clock dating method is based on biological heredity, meaning that all life inherits information in the form of genetic molecules (DNA) from the prior generation. Because this genetic material slowly transforms and changes over time, it therefore can be measured to ascertain how long ago evolutionary events took place. “Palaeontologists use the molecular clock technique to unveil deep history, often in groups with poor fossil records. For example, penguins are known to be descended from a recent (geologically speaking) ancestor, around 20 million years ago, while the first complex cellular life is now known to have emerged from bacterial lineages more than 1.2 billion years ago. These examples provide valuable insight into past environmental and ecological conditions, and expand our knowledge of the dynamics of evolution.� Source: http://theconversation.com/explainer-what-isthe-molecular-clock-46242
The Molecular Clock Source: http://popista.com/molecularclockhttp://popista.com/molecularclockhttp://popista.com/molecular-clock
Speciation Speciation, the formation of original and unique species in the course of evolution as a result of behavioural, geographical, physiological, and anatomical factors stops Donec previously inter-breeding populations from mating or interdum breeding with one another, involves the breaking or splitting of one single evolutionary ancestry into two or more completely different genetic lineages. Two types of speciation are sympatric and allopatric. Sympa tr ic specia t ion is whereby new species evolve within a certain geographical region, then they mate and interbred with their ancestors and over time become the dominant form of the species and therefore the species that preceded their evolution become weaker and are slowly weeded out. Example of sympatric speciation is the divergence of "resident" and "transient “ killer whale forms in the northeast Pacific Ocean.
Charles Darwin 1809-1882
Natural Selection It is through genetic molecules (DNA) make-up that organisms and species are unique and are able to survive and evolve. “Natural selection, the process of which certain inherited traits make it easier for some individuals to thrive and multiply changing the genetics make-ups of population over time.” Source: https://fr.khanacademy.org/science/biology/crash-course-bioecology/crash-course-biology-science/v/crash-course-biology-113
C ha r les Da r win argued that Natural Selection contributed greatly to the Theory of Evolution. He argued that Natural Selection, the process by which organisms and species adapted to their environment and the conditions within it and were able to reproduce, was responsible for the survival and evolution of the species. Natural selection causes evolutionary change because it changes the genetic composition of entire populations through the interaction of individuals with their environment. For example, “antibiotic resistance (ability of a microorganism to withstand the effects of an antibiotic) …evolves naturally via natural selection through random mutation, but it could also be engineered by applying an evolutionary stress on a population.”
Source: http://apesrk.blogspot.com.au/2014_11_01_archive.html
Allopa t ric specia tio n involves the separation of the same species and the divergent evolution of each of the separated populations according to their experience with and encountering of the environment and conditions that they are confronted with. A noted example of Allopatric speciation is “Darwin’s finches on the Galapagos Islands, which may have speciated allopatrically because of volcanic Consectetuer: eruptions divided populations.”
Source: https://www.sciencedaily.com/terms/antibiotic_resistance.htm
Source: http://www.britannica.com/science/speciation
Evolutionary Theory is Accurate It is debated outside of scientific circles whether Evolutionary theory is accurate or not. Scientists in different fields such as Biology, Genetics, Geology, Paleontology and Paleoanthropology, concerned with evolution have given foundation to support and credibly substantiate the theory. The fossil record convincingly supports the Theory of Evolution as proposed by Charles Darwin’s process of Natural Selection and this is demonstrated through the record exhibiting that the organisms inhabiting Earth have become increasingly sophisticated over time, and that some species that once existed are now non-existent. Fossil evidence also exists to support the very slow and gradual transformation of particular organisms or species. By studying the genetic makeup of organisms or species it can be concluded that organisms that are more closely related to each other possess closer or similar DNA make-ups. This has resulted due to the two or more populations coming from the same lineage but due to environment factors and differing conditions have changed by themselves over time to adapt and survive.
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C ASE ST UDY: HUM AN E VOLUT ION Human evolution is the result of two factors intertwined – physical (genetic) and behavioural change. It is through the process of biological evolution that all species or organisms have originated. Scientists classify each species with a unique, two-part scientific name, therefore that is why modern humans are classified as Homo-sapiens. The term species refers to a group whose adult members regularly interbreed, producing offspring that are capable of reproducing themselves, thus increasing the possibility of the continuance of the evolution of that species.
Source: https://static.squarespace.com/static/54445da1e4b02b47d4967a37/5 4485e3be4b0c9296f40db86/54485e3ce4b0c9296f40dd4d/13385616 01873/1000w/brain_evolutionjpg.jpg
Gradual genetic change over time, this may be thousands of years, can alter a species' overall way of life, in terms of how and what it eats, how it grows, and where it inhabits. Human evolution occurred as new genetic variations in early ancestor populations favoured new abilities to adapt to environmental change and hence the alteration of the human way of life.
The evolution of humans involves the study of fossils and others forms of evidence that document the change in the physical appearance and structure of homo-sapiens over time as well as their behavior. Scientific evidence suggests that humans evolved from Ape like creatures over a period of approximately 6 million years. Scientists agree that there were 15 to 20 different species of early humans and that over time some of these died out through because of evolutionary and environmental factors and in some cases for unexplained reasons.
Throughout the evolution of humans into the modern human form there have been certain traits and behaviors that have set humans apart from their ape ancestors. One of these is bipedalism, being the ability of humans to walk on two legs and move efficiently around their environment, this which evolved over 4 million years ago. Another is the development of the human brain, skull and face from a small brain and skull structure with a large sloping face to a large skull and brain with a smaller face. Human evolution has also included the development of tools to aid in survival, and the ability to communicate and interact with one another through the development of language.
Humans are considered primates because our genetic and physical make-up has many similarities to those of the primate group of Apes, in particular the Apes of Africa. According to fossil evidence, humans evolved in Africa over a period of 6 million to 2 million years ago. Evolution occurs through change in genetic material - the chemical molecule, DNA. This DNA is inherited by the species off-spring from their ‘parents’. Information within the DNA can evolve through the process known as mutation. The way particular genes influence the body or behaviour of an organism can also change over time. Genetic make-up affects how the body and behavior of an organism develops and this explains why genetically inherited characteristics influence the chances of an organism’s survival and reproduction.
Development of tools contributed to human evolution Source: http://vishwamitra.tripod.com/edu/ch17.htm
“Paleoanthropology, the scientific study of human evolution, is a subfield of anthropology, the study of human culture, society, and biology.” Fossils and archeological remains provide clues and evidence in relation to human evolution. Through fossilized remains such as bones, tools and footprints, fire places, or cutting marks and incisions on animal bones, scientists can study and document the physical appearance of humans from their earliest forms to now and how they have evolved/changed over time. In conjunction with the contribution of archaeological evidence, understanding how early humans made and used tools and lived in their environments, scientists can develop a more comprehensive ‘picture’ of human evolution.
Stages of Human Evolution: from Apes to Homo-sapiens Source: https://sites.psu.edu/siowfa15/2015/09/18/evolution-2/
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Source: evolution
http://humanorigins.si.edu/education/introduction-human-
BIBLIOGRAPHY VID EOS Khan Academy, 2011, ‘Human Evolution Overview’, viewed May 2016, https://www.youtube.com/watch?v=frE1rjhH77Y Khan Academy, ‘Natural Selection’, viewed May 2016, https://fr.khanacademy.org/science/biology/crash-coursebio-ecology/crash-course-biology-science/v/crash-course-biology-113 Sam Gaffney, 2014, ‘Evolution: The Evolution of humans’ documentary, viewed May 2016, https://www.youtube.com/watch?v=MsHEAnPX59Y Stated Clearly, 2013, ‘What is Evolution’, viewed May 2016, https://www.youtube.com/watch?v=GhHOjC4oxh8 ZDF Enterprises, 2016, ‘Human Evolution’, viewed May 2016, http://www.britannica.com/science/evolution-scientific-theory/The-science-of-evolution W EB SI TES About Education, 2016, ‘Biological Evolution’, viewed May 2016, http://biology.about.com/od/evolution/a/aa110207a.htm BBC, 2014, ‘Science: Natural selection and Evolution’, viewed May 2016, http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway_pre_2011/environment/4_survival_of_fittest4.shtml BBC, 2014, ‘Theory of Evolution: Evidence for Darwin’s Theory of Evolution’, viewed May 2016, http://www.bbc.co.uk/schools/gcsebitesize/science/21c_pre_2011/evolution/theoryevolutionrev7.shtml Biologos, 2016, ‘Scientific Evidence: What does the fossil record show?’, viewed May 2016, http://biologos.org/common-questions/scientific-evidence/fossil-record/ Encyclopaedia Britannica, Inc, 2016, ‘The Science of evolution’, viewed May 2016, http://www.britannica.com/science/evolution-scientific-theory/The-science-of-evolution#toc49895 Encyclopaedia Britannica, Inc, 2016, ‘Speciation’, viewed May 2016, http://www.britannica.com/science/speciation Jacaranda Plus, http://content.jacplus.com.au/faces/pages/ebookviewer.xhtml?isbn=1118606353&chptr=10463&sectionNo=7&pag eType=1&view=01&cb=542149145621 http://content.jacplus.com.au/faces/pages/ebookviewer.xhtml?isbn=1118606353&chptr=10463&sectionNo=6&pag eType=1&view=01&cb=3840168535243 http://content.jacplus.com.au/faces/pages/ebookviewer.xhtml?isbn=1118606353&chptr=10463&sectionNo=5&pag eType=1&view=01&cb=5416460316628 http://content.jacplus.com.au/faces/pages/ebookviewer.xhtml?isbn=1118606353&chptr=10463&sectionNo=4&pag eType=1&view=01&cb=5825867038220 http://content.jacplus.com.au/faces/pages/ebookviewer.xhtml?isbn=1118606353&chptr=10463&sectionNo=8&pag eType=1&view=01&cb=2603288546670
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Live Science, 2015, ‘What is Darwin's Theory of Evolution?’, viewed May 2016, http://www.livescience.com/474controversy-evolution-works.html Nickels, Martin (Illinois State University), 2001, ‘Humans As a Case Study for the Evidence of Evolution’, Viewed May 2016, http://www.talkorigins.org/faqs/homs/evidence_mn.html Nature Education, 2014, ‘Human Fossil Record’, viewed May 2016, http://www.nature.com/scitable/knowledge/human-fossil-record-98011840 Nature Education, 2014, ‘Overview of Hominin Evolution’, viewed May 2016, http://www.nature.com/scitable/knowledge/library/overview-of-hominin-evolution-89010983 Public Library of Science (PLOS), 2012, ‘Human Origins and the Search for “Missing Links”’, viewed May 2016, http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1001333 Public Library of Science (PLOS), 2006, ‘When Less Is More: Losing Genes on the Path to Becoming Human’, viewed May 2016, http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.0040076 Regents of the University of Michigan, 2002, ‘The Process of Speciation’, viewed May 2016, http://www.globalchange.umich.edu/globalchange1/current/lectures/speciation/speciation.html Science Daily, 2016, ‘Antibiotic Resistance’, viewed May 2016, https://www.sciencedaily.com/terms/antibiotic_resistance.htm Smithsonian Institution, 2016, ‘Introduction to Human Evolution’, viewed May 2016, http://humanorigins.si.edu/education/introduction-human-evolution Study.com, 2003-2016, ‘Speciation: Definition, Examples & Role in Evolution’, viewed May 2016, http://study.com/academy/lesson/speciation-definition-examples-role-in-evolution.html The Conversation Media Group Ltd, 2010-2016, ‘Explainer: what is the molecular clock?’ viewed May 2016, http://theconversation.com/explainer-what-is-the-molecular-clock-46242 Understanding Evolution, 2016, ‘Natural Selection’, viewed May 20167, http://evolution.berkeley.edu/evolibrary/article/evo_25 Wiley Online, 2000-2016, ‘Speciation and the Fossil Record’, viewed May 2016, http://www.els.net/WileyCDA/ElsArticle/refId-a0001666.html PI C TURES /DI AG RAMS http://darwinandthegalapagos.weebly.com/uploads/5/3/6/8/53683367/3962471_orig.jpg http://popista.com/molecular-clockhttp://popista.com/molecular-clockhttp://popista.com/molecular-clock https://s-media-cache-ak0.pinimg.com/736x/38/ff/30/38ff30c59b16e2ad197b8a1b2b9b8f4b.jpg https://static.squarespace.com/static/54445da1e4b02b47d4967a37/54485e3be4b0c9296f40db86/54485e3ce4b0c9296f40dd4d/ 1338561601873/1000w/brain_evolutionjpg.jpg http://vishwamitra.tripod.com/edu/ch17.htm https://sites.psu.edu/siowfa15/2015/09/18/evolution-2/ http://apesrk.blogspot.com.au/2014_11_01_archive.html
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