BIOLOGY LIFE ON EARTH 10TH EDITION AUDESIRK
FULL DOWNLOAD AT LINK:
Test Bank: https://testbankpack.com/p/test-bank-for-biology-life-onearth-with-physiology-10th-edition-by-audesirk-byers-isbn0321794265-9780321794260/
Solution Manual: https://testbankpack.com/p/solution-manual-forbiology-life-on-earth-with-physiology-10th-edition-by-audesirkbyers-isbn-0321794265-9780321794260/
CHAPTER 18 SYSTEMATICS: SEEKING ORDER AMID DIVERSITY
LECTURE OUTLINE
Case Study: Origin of a Killer
18.1 How Are Organisms Named and Classified?
A. TheBranchofBiologyConcernedwithNamingandClassifyingOrganismsIsKnownasTaxonomy
1. ThebasisofmoderntaxonomywasdevelopedbyCarolusLinnaeus
a. Heintroducedthetwo-partscientificnamingoforganisms
B.EachSpeciesHasaUnique,Two-PartName
1. Thescientificnameofanorganismdesignatesitsgenusandspecies (Figure 18-1)
C ModernClassificationEmphasizesPatternsofEvolutionaryDescent
1. Theprocessofclassificationfocusesalmostexclusivelyonreconstructingphylogeny,orevolutionary history
2. Thescienceofreconstructingphylogenyisknownassystematics
D.SystematistsIdentifyFeaturesThatRevealEvolutionaryRelationships
1. Theymustdistinguishbetweensimilaritiesamonglivingorganismsthatstemfromconvergent evolutionorinheritancefromacommonancestor
2. Systematistslookcarefullyatsimilaritiesinbothexternalandinternalstructure (Figure 18-2)
E ModernSystematicsReliesonMolecularSimilaritiestoReconstructPhylogeny
1. Systematistscanusesimilaritiesinnucleotidesequencesandchromosomestoinvestigate relatednessbetweenorganisms (Figure 18-3)
â Lecture Activity 18.1: Molecular Systematics
â In Greater Depth: Phylogenetic Trees (Figures E18-1, E18-2, and E18-3)
â Links to Everyday Life: Small World
F. SystematistsNameGroupsofRelatedSpecies
1. Systematistsnamegroupscalledclades,whichincludespecieslinkedbydescentfromacommon ancestor (Figure 18-4)
a. Whensystematistsnameaclade,thenameitselfdoesnotconveymuchinformation
b. Onewaytorevealtheinclusivenessofacladeistousetaxonomiccategoriesthatforman increasinglyinclusivenestedhierarchy
i.TheLinnaeanclassificationcametoincludeeightcategories
ii.Domain,kingdom,phylum,class,order,family,genus,andspecies
iii.Therankingsystemdoesposevariousproblemsforcategorizingorganisms
â Lecture Activity 18.2: Hierarchical Categorization
â Lecture Activity 18.3: Hardware Taxonomy
G. UseofTaxonomicRanksIsDeclining
18.2 What Are the Domains of Life?
A. Bythe1970s,SystematistsConcludedfromtheAvailableEvidenceThattheEarliestSplitintheTreeof LifeDividesAllSpeciesintoFiveKingdoms
1. Asknowledgeoflife’sevolutionaryhistoryexpanded,itbecameapparentthatthiswasan oversimplification
B. AThree-DomainSystemMoreAccuratelyReflectsLife’sHistory
1. CarlWoeseandotherresearchersstudyingRNAnucleotidesequencesshowedthatprokaryotes includetwoverydifferentkindsoforganisms (Figure 18-5)
2. Thisclassificationschemedividesorganismsintothreedomains
a. Bacteria,Archaea,andEukarya (Figure 18-6)
Copyright © 2012 Pearson Education, Inc.
b. Eukaryaisdividedintoavarietyofclades,includingplants,fungi,andanimals,andaseparate groupgenericallycalled“protists” (Figure 18-7)
â Lecture Activity 18.4: Exploring the Tree of Life (Parts 1 and 2 of Procedures)
18.3 Why Do Classifications Change?
A. TheHypothesesofEvolutionaryRelationshipsonWhichClassificationIsBasedAreSubjecttoRevision asNewDataBecomeAvailable
B. SpeciesDesignationsChangeWhenNewInformationIsDiscovered
C. TheBiologicalSpeciesDefinitionCanBeDifficultorImpossibletoApply
1. Thebiologicalspeciesdefinitionfailsforasexuallyreproducingspecies
2. Thephylogeneticspeciesconceptoffersanalternativedefinition
a. Thisconceptdefinesaspeciesasthesmallestdiagnosablegroupthatcontainsallthedescendents ofasinglecommonancestor
18.4 How Many Species Exist?
A. ScientistsDoNotKnowHowManySpeciesExistonEarth
â Lecture Activity 18.4: Exploring the Tree of Life (Part 3 of Procedures)
1. Between7,000and10,000newspeciesareidentifiedannually
2. Thetotalnumberofnamedspeciesisapproximately1.5million
3. BiodiversityisthenumberandvarietyofEarth’ sspecies
4. Destructionofrainforestscouldendangerundiscoveredspecies (Figure 18-8)
Case Study Revisited: Origin of a Killer
KEY TERMS
Archaea genus Bacteria phylogeny biodiversity scientificname clade species domain systematics Eukarya taxonomy
LECTURE ACTIVITIES
Lecture Activity 18.1: Molecular Systematics
Estimated Time to Complete:10–15minutesineachoftwoconsecutiveclasses
Section Reference
18.1HowAreOrganismsNamedandClassified?
Introduction
SystematiststodaycomparenucleotidesequencesofhomologousDNAregionsofvariousspeciestotryto reconstructtheevolutionaryrelationshipsofthesespecies.Sequencecomparisonsareoftenfraughtwith problemssuchasdeletionsandinsertionsofnucleotidesduringtheevolutionarydivergenceofgroups,butthere arecomputeralgorithmsforalignmentofDNAsequences.Oncealigned,nucleotidepositionsthatarevariable haveinformationabouttherelationshipbetweenthem;thosepairsthathavemorematchesbetweenthemare morecloselyrelatedandbyinferencehavesharedacommonancestormorerecently.
Copyright © 2012 Pearson Education, Inc.
Inthisexercise,studentswillcomparethreeDNAsequencesandformulatetherelationshipsamongthethree ofthem.AllaresequencesoftheNADHdehydrogenasesubunit3(ND3)gene,locatedonthemitochondrial genome.Sequence1istakenfrom Homo sapiens (human),Sequence2isfrom Rattus norvegicus (rat),and Sequence3isfrom Mus musculus (mouse).Studentswillfindthattheratandmousesequencesaremostclosely related,andthehumansequenceisaboutequallyrelatedtobothoftheothertwo.
Theexerciseworksbestifitisassignedandintroducedinoneclassperiod,completedforhomework,and discussedinthefollowingperiod.
ThethreesequenceswereobtainedfromtheEntrezonlinegeneticdatabasesponsoredbytheU.S.National CenterforBiotechnologyInformation(NCBI) (http://www.ncbi.nlm.nih.gov/Database),whichallowsfreeaccess andsearchcapabilities.
Materials Needed
None
Procedures
1. IntroduceorreviewtheuseofDNAsequenceinformationinsystematics.
2. Distributetheaccompanyinghandoutand,usingtheprovidedinstructions,explaintheexercise.Donot revealthespeciesfromwhichthesequencesaretaken.Foreachnucleotidepositionthathasamatch betweentwoofthethreesequences,studentswillcirclethetwonucleotidesthatmatch.Then,theywill countthenumberofpositionsthathavematchesbetweenSequences1and2,betweenSequences1and3, andbetweenSequences2and3.Theexerciseandquestionsonthehandoutshouldbecompletedfor homework.(Theinstructormaywanttotakethelast10minutesofclasstointroducetheassignmentand havethestudentsbeginworkonit,incasetherearequestions.)
3. Inthenextclass,discusstheresultsusingthequestionsonthehandoutasaguide.Afterthediscussion, revealthenamesofthespeciesfromwhichthesequencesaretaken.
Assessment Suggestions
Beginbyaskingtheresultsoftheiranalysislocatedatthebottomofthefirstpageofthehandout.Thecorrect numbersofsequencematchesareasfollows:
Only1and2match:24
Only1and3match:26
Only2and3match:74
Discusstheanswerstothequestionsonthehandout:
1. Whichtwosequencesaremostcloselyrelated?Howdoyouknow? (Sequences 2 and 3 are the most closely related, as they have the most number of pairwise matches. There are about three times more matches in the Sequences 2 and 3 comparison than in the other two pairs.)
2. Istheleastrelatedsequenceaboutequallyrelatedtotheothertwo?Howdoyouknow?Whatdoesthis suggestabouttheevolutionaryhistoryofthethreespecies?
(Yes, Sequence 1 has about the same number of matches with Sequence 2 [24] as it does with Sequence 3 [26]. This means that the ancestor of Sequence 1 diverged from a common ancestor of Sequences 2 and 3, and that 2 and 3 have evolved at about the same rate over time.)
3. Drawaphylogenetictreediagramthatshowstherelationshipbetweenthethreesequences. (The tree should look something like the following picture. The identity of the three species could be revealed at this point in the discussion.)
Copyright © 2012 Pearson Education, Inc.
4. Whyaretheresomepositionsinwhichnoneofthethreesequencesmatch?
(These positions represent nucleotides that have evolved in at least two, and perhaps all three, of the species’ lineages since their divergence from the common ancestor.)
Handouts or Display
Seethefollowingpages.
Copyright © 2012 Pearson Education, Inc.
Name: Date:
Instructor:
CourseSection:
Lecture Activity 18.1 Handout—Molecular Systematics
ThreealignedDNAsequencesarelistedbelow.AllthreearesequencesoftheNADHdehydrogenasesubunit3 (ND3)gene,whichislocatedonthemitochondrialgenome,thesmallcircularDNAmoleculecarriedinthe mitochondriaofeukaryotes.Eachofthethreesequencesistakenfromadifferentmammalianspecies,anditis yourjobtodeterminetheevolutionaryrelationshipofthethreespeciesusingthesedata.
Sequence1 ATAAACTTCGCCTTAATTTTAATAATCAACACCCTCCTAGCCTTACTACAATAATTATT
Sequence2 ATTAACCTACCCATTATCATCACAATTAACATCACCTTATCCTTTATCCTCATTTCAATT
Sequence3 ATCAACCTGTACACTGTTATCTTCATTAATATTTTATTATCCCTAACGCTAATTCTAGTT
Sequence1 ACATTTTGACTACCACAACTCAACGGCTACATAGAAAAATCCACCCCTTACGAGTGCGGC
Sequence2 GCATTCTGATTGCCTCAAATAAACTTATACTCCGAAAAAGCAAACCCATATGAATGTGGC
Sequence3 GCATTCTGACTCCCCCAAATAAATCTGTACTCAGAAAAAGCAAATCCATATGAATGCGGA
Sequence1 TTCGACCCTATATCCCCCGCCCGCGTCCCTTTCTCCATAAAATTCTTCTTAGTAGCTATT
Sequence2 TTCGACCCAACAAGTTCTGCACGCCTTCCTTTTTCAATAAAATTTTTCTTAGTAGCCATT
Sequence3 TTCGACCCTACAAGCTCTGCACGTCTACCATTCTCAATAAAATTTTTCTTGGTAGCAATT
Sequence1 ACCTTCTTATTATTTGATCTAGAAATTGCCCTCCTTTTACCCCTACCATGAGCCCTACAA
Sequence2 ACATTTCTACTATTCGACCTAGAAATCGCCTTACTACTTCCCCTCCCATGAGCGATTCAA
Sequence3 ACATTTCTATTATTTGACCTAGAAATTGCTCTTCTACTTCCACTACCATGAGCAATTCAA
Sequence1 ACAACTAACCTGCCACTAATAGTTATGTCATCCCTCTTATTAATCATCATCCTAGCCCTA
Sequence2 ACAACCAATACCACTACAATAATAGCAACTGCCTTTATTTTAGTCACTATTTTGTCTCTT
Sequence3 ACAATTAAAACCTCTACTATAATAATTATAGCCTTTATTCTAGTCACAATTCTATCTCTA
Sequence1 AGTCTGGCCTATGAGTGACTACAAAAAGGATTAGACTGAGCCGAAT
Sequence2 GGCCTAGCCTACGAATGAACACAAAAAGGACTAGAATGAACAGAATAA
Sequence3 GGCCTAGCATATGAATGAACACAAAAAGGATTAGAATGAACAGAGTAA
*********************************
SystematistsusecomputerprogramstocompareandanalyzeDNAsequencedata,aswellastodrawthetree diagramsthatgraphicallyshowtherelationshipsbetweenthesequences.Thesesequenceswerealignedand displayedasaboveusingonesuchprogram.Therearefourlinestotheanalysis.Thefirstthreelineshavethe alignedsequences;a“dash”symbol(“ ”)indicatesagapinthealignment.Thefourthlinehasmatching informationforthethreesequences;anasterisk(*)indicatesthatallthreesequencesmatchatthatposition,anda spaceindicatesthatallthreedonotmatch.
Lookateachpositionwhereallthreedonotmatch.Iftwoofthethreematch,circlethetwothatmatch.Then, countthenumbersofpositionsthatshowthefollowing:
Only1and2match:_____
Only1and3match:_____
Only2and3match:_____
Now,answerthefollowingquestions:
1. Whichtwosequencesaremostcloselyrelated?Howdoyouknow?
2. Istheleastrelatedsequenceaboutequallyrelatedtotheothertwo?Howdoyouknow?Whatdoesthis suggestabouttheevolutionaryhistoryofthethreespecies?
3. Drawaphylogenetictreediagramthatshowstherelationshipbetweenthethreesequences.
4. Whyaretheresomepositionsinwhichnoneofthethreesequencesmatch?
Lecture Activity 18.2: Hierarchical Categorization
Estimated Time to Complete: 5–10minutes
Section Reference
18.1HowAreOrganismsNamedandClassified?
Introduction
Thisclassexerciseisaquickandeasywaytoillustratethepracticeofhierarchicalcategorizationandthe sometimesarbitrarynatureofchoosingwhicharetobehigher-levelandlower-levelcategories.Studentsin groupsaregivenaseriesofcoloredshapestocategorize.Theycanquicklydecidethehigher-levelcategorical criterion(colororshape)andformgroupsbasedonsimilarity.Thediscussionfollowingtheexercisecanlead studentsintothinkingabouthowbiologistsdecidewhatcriteriaaremoreimportantinestablishinga classificationhierarchyoforganisms.
Materials Needed
• Severalgroupsofdifferentlyshapedpiecesofplastic,withseveraldifferentcolorsofeach.(Ifthesearenot available,coloredshapesprintedonpaperwillsuffice;seetheaccompanyinghandout.)
Procedures
1. Beforeclass,obtainplasticobjectsofdifferentshapesandvariouscolors(suchasblue,red,andyellow spheres;blue,red,andyellowpyramids;etc.)andputidenticalcollectionsinseveralbags.Onebagwillbe giventoeachstudentgroup.(Alternatively,printseveralcopiesoftheattachedhandoutonacolorprinter, cutouteachcoloredshape,andputeachcollectioninaplasticbaggie.)
2. Inclass,assemblethestudentsintoseveralgroups,andgiveeachgroupabag.Tellthegroupstodecidehow tocategorizetheshapes,andthenputtheshapesintogroupsbasedontheirdecisions.
3. Discusstheirdecisionsusingthequestionsinthe Assessment Suggestions section.
Assessment Suggestions
Followingtheexercise,haveeachgrouppresentandexplainitscategorization.(Somegroupswillhavechosen “shape”asthecategorycriterion,withallcolorsofthesameshapeinthesamecategory;otherswillhavechosen “color”asthecategorycriterion,withallshapesofthesamecolorinthesamecategory.)Keepatallyofhowmany groupschoose“shape”andhowmanychoose“color.”Withtheentireclass,discusstheresultsasfollows:
1. Whichisbettertochooseforcategorizingtheseobjects,shapeorcolor?
(Neither is really better; the choice is arbitrary. It depends on whether the person doing the categorizing feels that shape or color is more important, and should be used as a higher-level category.)
2. Inassigningbiologicalspeciestocategories,aretheresomecharacteristicsthataremoreorlessimportant? Ifso,whatarethey?
(Yes, important characteristics might be cell structure [prokaryote or eukaryote], method of obtaining energy [photosynthetic or heterotrophic], and so on. Less important characteristics might be color or size.)
3. Whyaretheimportantcharacteristicsimportant?
(They represent major, fundamental biological differences among organisms.)
4. Whyarethelessimportantcharacteristicslessimportant?
(They represent ways in which biologically very similar organisms may vary, or change over a period of development.)
5. Whatshouldabiologistdoif,aswiththecoloredshapes,somecharacteristicsarenotanymoreorless importantthanothers?
(The biologist may choose a category arbitrarily, until and unless more data make it clear that one character is “better” than another and warrants being placed at a higher level.)
Handouts or Display
Seethefollowingpage.
Copyright © 2012 Pearson Education, Inc.
Lecture Activity 18.3: Hardware Taxonomy
Estimated Time to Complete: 15–20minutes
Section Reference
18.1HowAreOrganismsNamedandClassified?
Introduction
Thisexercisemaybedoneinadditionto,orinsteadof,LectureActivity18.2(HierarchicalCategorization). Taxonomists(biologistswhocategorizeorganismsintothehierarchicalsystemofbiologicalclassification)have historicallyusedthephysicalcharacteristicsoforganismsasthebasisforassigningorganismstothesameor differentbiologicalcategoriesofvariouslevels.Today,taxonomyisrootedinthefieldofsystematics,the determinationofevolutionaryrelationshipsbetweenspecies.Althoughothertypesofdata(suchasbehavior, geographiclocation,andgeneticcomparisons)areusedtoassesssimilarity,morphologicalcharacteristicsarestill importantindeterminingsimilarity,andinferringrelatedness. Withthisactivity,studentswillbepresentedwithacollectionofsmallhardwareitems,suchasnutsand bolts,chooseahierarchicalsystemofcategorization,andassigneach“species”itstaxonomicplace.Studentsgeta feelforthedifficultyofsuchwork,andthesometimesarbitrarynatureofdeciding“higher-level”and“lowerlevel”variability.
Materials Needed
• Bagsofvarioustypesofhardwarepieces,orpicturesofthedifferenttypes.Forsuggestedpictures,performan Internetsearchusingtheterms“brassfittings.”
Procedures
Theinstructorshouldobtainanumberofsmallinexpensivehardwarepieces,availableatanyhardwarestoreor department.Thepiecesshouldvaryinsize,shape,color,andfunction,sothattherearemanypossiblewaysto categorizethepieces.Prepareabagofpiecesforeachcollaborativegroupofstudentsintheclass.
1. Dividetheclassintoseveralgroupsandprovideeachwithabagofhardwarethatincludesvarioustypesof nutsandbolts.Askeachgrouptocategorizethecollectionintoahierarchyofmajorcategories,minor categorieswithineachmajorcategory,and(ifpossible)subcategorieswithineachminorcategory.
2. Afterabout5minutes,haveeachgrouppresentitscategorizationsystem,includingthehighest-level category,thenext-levelcategory,andsoon.Askthemembersofeachgrouptotellwhytheyrankedthe characteristicsasmoreorlessimportant,andconcludewithadiscussionofhowbiologicalclassification decisionsaremade.(See Assessment Suggestions forguidingdiscussionquestions.)
Assessment Suggestions
Askeachgrouptorespondtothefollowingquestions:
1 Whatisthehighest-levelcategorycharacteristicinyoursystem?Whatisthenext-levelcharacteristic?etc. (Many will probably choose function [if known] or shape of the piece as the highest level of categorization. Characteristics such as size or color may be lower or lowest-level categories.)
2. Whydidyouchoose (thehighest-levelcharacteristic)asmostimportant? (As groups respond to this question, write the responses on a blackboard or display for the discussion to follow.) Wheneachgrouphasresponded,considertheresults.
3. Aresomecharacteristicsfrequentlychosenforthehighestlevel?Isthereaconsensusonrankingthe importanceofthecharacteristics?
(Probably, there will be some agreement that function and shape are very important, size and color less so.) Discusswiththeclass:
4. Whataresomehigher-levelorimportantcharacteristicsforcategorizingbiologicalspecies?
(Again, write and display the responses. Students may consider such things as cell structure, method of obtaining energy, method of reproduction, or body structure as very important, whereas size and color should be considered to be less important.)
Copyright © 2012 Pearson Education, Inc.
5. Itseemstobeeasiertodecidewhatcharacteristicsareveryimportantorunimportantincategorization,but thereisdisagreementontheintermediatelevels.Whatcanbiologistsdotodecidehowtoestablishthese intermediatecharacters?
(This may be a difficult question for the students to answer. If so, point out that species that are very different, and would be categorized in a different higher-level category, differ in a suite of characters, not just a few. Once a group showing higher-level similarity is established, variation among members of the group then becomes more important for subcategorization, and establishing the next most important set of differences is easier.)
Copyright © 2012 Pearson Education, Inc.
Lecture Activity 18.4: Exploring the Tree of Life
Estimated Time to Complete: 5-minuteintroductioninoneclass,and20minutesforgrouppresentationsina laterclass
Section Reference
18.2WhatAretheDomainsofLife?
18.4HowManySpeciesExist?
Introduction
TheTreeofLifeWebProject (http://www.tolweb.org/tree/) isaprofessionallymaintained,regularlyupdated, peer-reviewedWebsitewithinformationonevolutionaryrelationshipsandthebiodiversityoftaxonomicgroups. Theinformationisarrangedinthesamewayasthebiologicalclassificationsystem,butpresentedinawaythatis easyforbiologystudentstoaccess.Forexample,bothscientificandcommonnamesareincludedinthe hierarchicalarrangementoftaxa(e.g.,Annelida[segmentedworms]).Thesitewasoriginallydesignedforuseby professionaltaxonomistsandsystematists,butisalsoofuseforbiologyeducationattheundergraduatelevel.
Eachindividualpageforagroupoforganismsonthesitehasseveralsections:picturesofrepresentative organisms;aphylogenetictreeofsubtaxawithinthegroup;referencestojournalarticlesonthephylogenyofthe group;andlinkstomoreInternetinformationonthegroup.Eachpageiswrittenbyexpertsinthephylogenyof thegroup,andpeerreviewed.Anytentativeinformationislabeledassuch.
InpresentingmaterialfromSection18.2ofthetext(“WhatAretheDomainsofLife?”),thereisonepageon thesitethatisveryhelpful.Fromthehomepageofthesite(referencedabove),clickonRootoftheTree.This accessesapageentitled“LifeonEarth”thatpresentscurrentviewsontherelationshipsbetweenthethree domains:Archaea,Eubacteria(a.k.a.Bacteria),andEukaryotes(a.k.a.Eukarya).Althoughcurrentdatasuggest thatArchaeaandEukaryaaremorecloselyrelatedtoeachotherthaneitheraretoEubacteria,thereissome controversyovertherelationshipsofspecificgroupsofArchaeatoEukarya.
IftheinstructorhasaccesstoacomputerdisplaysystemwithanInternetconnection,thispagecanbe accessedanddisplayedduringlecture,orprintedforclassdisplayordistribution.
Giventhevarietyandcomplexityofinformationonorganismalphylogenies,itisadvisabletoassigntakehomeprojectstostudents.Theresultsoftheseassignmentscanbesubmittedforgradingand/orpresentedin class.Onesuchassignment,asdetailedhere,wouldbeforeachstudenttoexploretherelationshipsbetweenthe threedomains,andtoresearchthebiodiversityofspecifictaxonomicgroupsasassignedbytheinstructor.
Materials Needed
• ClassroomcomputerdisplaywithInternetaccess(optional)
• EachstudentshouldhaveaccesstotheInternetfortake-homeassignments
Procedures
IntroducethematerialfromSection18.2ofthetext(“WhatAretheDomainsofLife?”)onthechangeinthe biologicalclassificationsystemfromthetwo-kingdomtothefive-kingdomsystem,andtherecentchangetothe three-domainsystem.Atthispoint,accessthe“LifeonEarth”pageoftheTreeofLifeWebsitetoshowthe alternatephylogeniesthatareindispute.Thelinktoaccessthissiteiscalled“TheRootoftheTree,”orthedirect linktothepageis http://www.tolweb.org/Life_on_Earth/1;thetwophylogeniesarereprintedhere.
Copyright © 2012 Pearson Education, Inc.
`==
Assignthestudentstocollaborativegroupsandgiveeachgroupacopyoftheaccompanyinghandout.Explainthat eachgroupistousetheTreeofLifeWebsiteto(1)researchandreportontherelationshipsbetweenthethree domains,and(2)researchthebiodiversityofaspecifictaxonomicgroup,tobeassigned.(Seethefollowinglistfor suggestions.)HavetheduedatebethedaythatSection18.4ofthetext(“HowManySpeciesExist?”)willbe presentedanddiscussed.Somesuggestionsfortaxonomicgroups:
Echinoderms (sea urchins, starfish, sea cucumbers, etc.)
Frogs
Mammals
Annelida (segmented worms)
Beetles
Wasps, Bees, and Ants
Flies
Butterflies and Moths
Spiders
Fungi
Flowering Plants
Duringtheclasscoveringthetopicofbiodiversity,haveaclassdiscussionoftheresultsofthe“three-domain” research,usingthequestionsonthehandoutasaguide.Also,haveeachcollaborativegroupgiveabriefreportof theanswerstothequestionsonthehandout.
Assessment Suggestions
TheanswerstothequestionsinPart1ofthehandout,whichcanbediscussedwiththeclassontheduedateof theassignment,areasfollows.
1. Whydoyouthinkthesearecalledsubsectionsratherthanphyla?
(Prokaryotes, including Bacteria, reproduce asexually, so that “populations,” “species,” and so on are really collections of independently evolving lineages that may occasionally exchange genetic material. The taxonomic system for prokaryotes is different from those of most eukaryotes because classification is based on the similarity of anatomical characteristics of various combinations. The intermediate levels of bacterial classification have different names because the designations of “class,” “order,” and “family” would not have the same meaning as they would for animals.)
2. Whicheukaryotickingdomcontainsmembersthatmaynotallbecloselyrelated?
(Protista has groups that are more closely related to animals [collar-flagellates], fungi [microsporidia], and plants [euglenids] than to other groups of protists.)
3. WhyareArchaeanscalled“life’sextremists”?
(Archaeans are often found in very extreme environments hot springs [high temperature], very acidic [low pH], or high-alkaline [high-pH] habitats.)
MakecopiesofPart2ofeachgroup’scompletedhandoutforeachmemberoftheclass,andincludequestions aboutthepresentedinformationonaquizorexam.
Handouts or Display
Seethefollowingpages.
Copyright © 2012 Pearson Education, Inc.
Name: Date:
Instructor: CourseSection:
StudentName(s):
NameofTaxonomicGroup(assignedbytheinstructor):
Lecture Activity 18.4 Handout—Exploring the Tree of Life
Part 1: TheThreeDomains
AccesstheTreeofLifeWebsiteontheInternet (http://www.tolweb.org/tree).ClickonthetextRootoftheTreeto accessthepage(entitled“LifeonEarth”)withinformationonthethreedomains:Archaea,Eubacteria(called “Bacteria”inyourtext),andEukaryotes(called“Eukarya”inyourtext).
1. ClickonEubacteriaonthephylogenetictree.Thisbringsupatreeshowingtherelationshipsbetweenthe “kingdoms”ofthisdomain.ClickonCyanobacteriatobringupalistof“Subsections.”Whydoyouthink thesearecalledsubsectionsratherthanphyla? (Hint:Whatisdifferentaboutbacterialgeneticsandevolutionascomparedtomosteukaryotes?)
2. Returntothe“LifeonEarth”pageandclickonEukaryotes.Whicheukaryotickingdomcontainsmembers thatmaynotallbecloselyrelated?
3. Returntothe“LifeonEarth”pageandclickonArchaea.Usethelinksatthebottomofthepagetoanswer thequestion: WhyareArchaeanscalled“life’sextremists”?
Part 2: Exploring (nameofassignedtaxonomicgroup)
ReturntothemainTreeofLifepage,clickonPopularPages,clickthenameofyourassignedgroup,andanswer thefollowingquestions.(Youmayneedtoexploretheprovidedlinkstoanswersomeofthem.)
1. Whatistheclassification“rank”ofyourgroup(kingdom,phylum,etc.)?
2. Whatarethemajorcharacteristicsofyourgroup?(Includeasmuchasyoucanfindfromthislist:habitat location,definitiveanatomicalattributes,behavior.)
3. Listthreerepresentativespeciesthatareclassifiedasmembersofyourgroup.
4. Clickononeofthehighlighted“subgroups”ofyourassignedgroup.Whichonedidyouchoose?Whatare someofthecharacteristicsofthe“subgroup”?