详解Biol2043生命起源

BIOLDarwinandDR.BONNYB.H.YUEENVIRONMENTALSCIENCEPROGRAMUNITEDINTERNATIONALCOLLEGEHANDOUTOriginof

Chapter2OriginofFirstHistoriesofFossilFactorsaffecting ChapterChapterOutline)3HistoryofEvolutionaryDarwin’sTheoryofEarth’sveryDescendwithchangefromacommonAdaptationtoachangingTheEvidenceofOriginof4“lifeonlycomesfromthefirstcellshadtoarisefromChemical omplexityofchemicalsthatledtothefirstMonomers5OrganicmonomerscouldhaveevolvedOuterCometsandEuropeanSpacesurfaceofCometReactionsintheStanley Monomers6StanleyMillerShowedthatgases(methane,ammonia,hydrogen,water)canreactwithoneanothertoproducesmallorganicmolecules→aminoacids,organicStrongenergyChemical7plumeofhotrichiniron-nickelMineralsthatformatdeep-seahydrothermalventslikethisonecancatalyzetheformationofammoniaandevenmonomersoflargerorganicmolecules.

ReactioninthePolymers8Monomersjointoformpolymersinthepresenceofproteinenzymesarose genescameRNAprogressedtowardformationofthefirstcellor genescameProtocell9Beforethefirsttruecellarose,therewouldhavebeenaprotocellorprotobiontprecursorstothefirsttruelipid-proteinmembraneandcarryonenergysmaand/orOriginofthefirstBiologicalBiologicaloriginofgiccode

ChemicalsmallChemical

Therewasanreaseomplexityof→self-replicatingsystem(→RNA→protein)enclosedbyasmamembrane.Theprotocellunderwentbiologicalevolution→true→

inorganicearlyearlyOriginoftheFirstAnabioticsynthesisprocesscreatedsmallorganicmolecules(monomers)suchasaminoacidsandnucleotidesatmosphereorhydrothermalmonomerjoinedtogethertoformpolymersalongtheshoreline(warmseasiderocksorclay)oratthevents.ThefirstpolymerscouldhavebeenproteinsorRNA,ortheycouldhaveevolvedtogether.Theaggregationofpolymersinsideasmamembraneproducedaprotocell,whichhadenzymaticpropertiessuchthatitcouldgrowOncetheprotocellcontained genes,atruecellhadevolved.ThefirstgenesmayhavebeenRNAmolecules,butlater etheinformationstoragemoleculeofheredity.Biologicalevolution–andthehistoryoflife–hadHistoryofLifeStrataStrata,layersseeninsedimentaryrocka posedbyroadcuts,arethesourceoffossilsthatlusaboutthehistoryoflife.HistoryofLifeFossilsmammothtusksin mammothtusksmammothtusksinfossildinosaurfossil fossildinosaur

dinosaurfootprintscorpioninamberFossilsaretheremainsofpastlife.Theycanbeimpressionsleftinrocks,footprints,mineralizedbones,ssoranyotherevidencesoflife-formsthatlivedinthepast.EvolutionaryfirstappearanceofHomosapiens land

11

P.M.

55 P.M. oxygen 1second=52,000yearsin 1minute=3,125,0001hour=187,500,000Thefossilrecordsuggeststhataverylargeportionoflife’shistorywasdevotedtotheevolutionoforganisms.Thefirstmulticelluarorganismsdonotappearinthefossilrecorduntiljustbefore8pm,andhumansarenotonthesceneuntillessthanaminutebeforemidnight.Treeof31

4

56

7first2

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543DuringthePrecambrianlife(4570-543mya),(1)thefirstcellorcellsgiveriseto(2)bacteriaand(3)(4)thefirsteukaryoticcellevolvesfromarchaea.(5)heterotrophicprotistsarisewheneukaryoticcellsmitochondriabyengulfingaerobicbacteria,and(6)photosyntheticprotistsarisewhenthesecellsgain stsbyengulfingphotosyntheticbacteria.(7)animals(andfungi)evolvefromheterotrophicprotists,and(8) ntsevolvefromphotosyntheticprotists.BYA=billionyearsagoEukaryoticCellsAbout1.8ContainsnucleusaswellasothermembranousHowdidthe1steukaryoticcellEndosymbiotic -livingaerobic- cyanobacteriumAnucleatedcellengulfedtheseprokaryotesthatbecamevariousorganellesCiliaandflagellamayhaveoriginatedfromslenderundulatingprokaryotesthatattachedtothehostcell

TheInvasionofSeedless ntsdatebacktoSilurianLater Arthropods节肢动物werefirstanimalsonOuterskeletonandjointedappendagespre-adaptedthemtoliveonFishesfirstappearedinOrdovicianFirstamphibiansappearedinDevonianGeologicalTheGeologicTimescale(referenceTheGeologicTimescale(cont’d)(referenceSwampsoftheCarboniferousSwampsoftheCarboniferous Vastswampoftreelikeclubmossesanddominatedthelandduringtheperiod.Theaircontainedinsectswithwidewingspans,suchasthepredecessorstodragonfliesshownhere,andlumberedfrompooltopool.Dragonflyfossilfromthe

FactorsFactorsThatInfluenceContinentaltContinentalPositionsofcontinentsandoceansarenotEarth’scrustconsistsofslab- tesfloatonalowerhotmantleMovements tes ontinentalFromSeedfernandmost ntsevolvedononecontinentandspreadtotheotherswhiletheywerestilljoinedasone lsevolvedafterthecontinentsContinental

a

About251mya,allthecontinentswerejoinedintoasupercontinentcalledDuringtheMesozoicera,thejoinedcontinentsofPangaeabeganmovingapart,formingtwolargecontinentscalledLaurasiaandGondwana.ThenallthecontinentsbegantoPresently,NorthAmericaandEuropearedriftingapartatarateofabout2cmper MeteoritecollisionwithContinental O2levelsinoceansaswellasinthe Atleastfivemajor tionshaveoccurredthrough438mya(millionyears75%ofspecies36070%ofmarineinvertebrates24590%ofoceanspecies20860%ofspecies6675%ofspecies Fivesignificantexttionsandtheireffectsontheabundanceofcertainformsofmarineandterrestriallife.Thewidthofthehorizontalbarsindicatesthevaryingabundanceofeachlife-formconsidered.MYA=millionyearsPartII:DarwinandChapterEarth’sveryDescendwithchangefromacommonAdaptationtoachangingTheEvidenceof

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eAeeribed

mania Tierradel VoyageoftheHMS

(a)MapshowsthejourneyoftheHMSBeaglearoundtheworld.(b)AsDarwintravelledalongtheeastcoastofSouthAmerica,henotedthatabird,calledrhea,lookedlikeanAfricanostrich.(c)thesparsevegetationofthePatagonianDesertisthesouthernpartofthecontinent.(d)TheAndesMountainsofthewestcoasthavestratacontainingfossilizedorganisms.(e)thelushtropicalraincontainsahighanduniquediversityoflife.(f)ontheGalapagosIslands,marineiguanashavelargeclawstohelpthemclingtorocksandbluntsnoutsforeatingalgaegrowingonrocks.(g)Galapagosfhesarespecializedtofeedinvariousways.Thisfhisusingacactusspoprobeforinsects.LateEighteenthCenturyLamarck(1744-LinkdiversitywithenvironmentalConcludedmorecomplexorganismsaredescendedfromlesscomplexEnvironmentcanbringaboutinheritede.g.,InheritanceofAcquiredThelongneckofagiraffedevelopedovertimebecauseanimalsstretchedtheirneckstoreachfoodintallandthenpassedonalongnecktotheirLarmarckianismvs.LateEighteenthCenturyCharlesLyell(1497-EarthissubjecttoslowbutcontinuouscyclesoferosionandProposedratesandprocessesofchangearee.g.Rainerodesmountains,whilemoltenrockpushesuptocreatenewDarwin’sTheoryofGeologicalobservationsconsistentwiththoseofHutton(1726-1797)&LyellThestudyofthegeographicdistributionoflifeformsonDarwinsawsimilarspeciesinsimilar→relatedspeciescouldbemodifiedaccordingtotheCharlesDarwinat31(1809-Biogeographyisthestudyoftherangeandgeographicdistributionoflife-formsonEarth omparedSouthAmericananimalstothosewithwhichhewasfamiliarInsteadofrabbits,hefoundthePatagonianhareinthegrasslandsofSouthAmerica.ThePatagonianharehaslonglegsandearsbutthefaceofaguinea PatagonianDidthePatagonianhareresemblearabbitbecausethetwotypesofanimalswereadaptedtothesametypeofenvironment?Bothanimalsategrass,hidinbushes,andmovedrapidlyusinglonghindDidthePatagonianharehavethefaceofaguinea commondescentwithguinea GalápagosDarwinobservedtortoisenecklengthvariedfromislandtoProposedthatspeciationonislandscorrelatedwithadifferenceinDarwinwonderedifalloftheGalapagostortoisesweredescendedfromacommonthetortoiseswithdomes andshortnecksfeedatgroundlevelandoccuronwellwateredlandswheregrassisavailable.thosewith sthatflareupinfronthavelongneckandareabletofeedontallcacti.Theylive aridlslandswhereprickypear-cactiarethemainfoodsource.Onlyontheseislandsarethecacti

GalápagosDarwinobservedmanydifferentspeciesof hesonvariousSpeculatedtheycouldhavedescendedfromasinglepairof NaturalSelection NaturalproposedbybothAlfredRusselWallace(1823-1913)andDrivingmechanismofevolutioncausedbyenvironmentalselectionoforganismsmostfittoreproduceresultinginadaptation eenvironmentchangesconstantly→NOperfectlyadaptedNaturalSelection IndividualshaveheritableMoreindividualsareproducedeachgenerationthantheenvironmentcansupportSomeindividualshaveadaptiveEnables🡩survivaland daptedtotheirlocalenvironmentthroughchangeinindividualsVariationinaForDarwin,variations,suchasthoseseeninahumanpopulation,arehighlysignificantandarerequiredfornaturalselectiontoresultinadaptationtotheenvironment.OrganismsHaveInheritableDarwinemphasizedthatindividualsfromapopulationvaryintheir:Inthepast,variationswereviewedasOrganismsHaveInheritableHeproposedthattheseNaturalselectiononlyoperatesonvariationsthatarealreadyavailablethepopulation’sgene icbinationofalleles ualArtificialSelectionofBostonBostonIrishScottishShihRedEnglishsheepdogShetland AlldogsaredescendedfromthegraywolfBegantobedomesticatedabout14,000yearsago ProcessofdiversificationhasbeenseparatedfromotherThewolvesseparatedfromotherEachhumantribeselectedforwhatevertraitsappealedtothemArtificialSelection Chinensisgroup

Brusselsprouts,

WildArtificialvs.NaturalArtificialSelectionbyhumanforthedesirede.g.,dog ntNaturalSelectionbythe→adaptationtotheNaturalObservationoftortoisesand hesontheGalápagosGalápagos 13speciesof heshaveabeakadaptedtoaparticularwayofHeavybeaksuitedtoadietoflargeBeakofthewarbler- hissuitedtofeedingonLongerbeak,somewhatdecurved,andthesplittonguesuitedtoprobingcactusa.Geospiza b.Certhidea c.CactornisGalapagos Eachofthepresent-day13 heshasabeakadaptedtoaparticularwayoftheheavybeakofthelargeground-dwelling h(G.magnirostris)issuitedtoadietoflargethebeakofthewarbler-f h(C.olivacea)issuitedtofeedingoninsectsfoundamonggroundvegetationorcaughtintheairthelongerbeak,decurved,andthesplittongueofthecactus-fh(C.scandens)aresuitedtoprobingacactusforseedsBeakNaturalselectioncanbe ndRosemaryGrant turalselectionasitWeatherinGalapagoIslandswungwidelybackandforthfromwettodryBeaksizeofmediumgroundf h,Geospizafortis,adaptedtoeachweatherswing,generationaftergenerationBeakDepthofGeospizawetBeakdry dry dryBeak Peakdepthofagroundfhvariesfromgenerationtogeneration,accordingtotheweather.Thesefhesliketoeatsmall,tenderseedsthatrequireasmallerpeak,butwhenweatherturnsdry,theyhavetoeatlargerseeds,whicharehardertocrush.Birdshavelargerbeakdepthhaveanadvantageandhavemoreoffspringindryseasons→nextgeneration,thebeaksizehasmoredepththanthepreviousgeneration.OrganismsDifferinFitnessistherelativereproductivesuccessofanThemost-fitindividualsinapopulationcaptureadisproportionateshareofgoodies ctionswiththeenvironmentdeterminewhichindividualsreproducethemostChangesthathelpa emoresuitedto ProductofnaturalEvidenceforEvidencesupportscommonFossil

FossilFossilsrecordthehistoryoflifefromtheasuccessionoflifeformsfromthesimpletothemoreSometimesthefossilrecordiscompleteenoughtoshowdescentfromanTransitionalfossilsareacommonancestorfortwodifferentgroupsoforganismsItallowstotracethedescentof

Transitionalbirdcharacteristics

Archaeopteryxwasatransitionallinkbetweendinosaursandbirds.Fossilsindicateithadfeathersandwingswithclaws,andteeth.Mostlikely,itwasapoorflier tailwithhada-

r

ptilian-typetailthatshowsupwellinthe’srepresentation.(orangelabels=reptiliancharacteristics;greenlabels=birdcharacteristic)AncesterotoAmbulocetus,anancestortowhalesdated40MYA.Thepresenceoflimbsisevidencethatwhalesevolvedfromland-basedancestors.studyofthedistributions ntsandanimalsacrossConsistentwithorigininonelocaleandthenspreadtoaccessibleHypothesizethatdifferentmixof ntsandanimalswouldbeexpectedwheneverGeographyseparates:e.g.,Continents,islands,MarsupialsarefoundinbothAustraliaandSouthAmericabutdiversifiedmuoreinAustraliaduetoofcentalm ls.Eachtypeofmarsupial(pouchedanimal)inAustraliaisadaptedtoadifferentwayoflife.AllofthemarsupialsinAustraliapresumablyevolvedfromacommonancestorthatenteredAustraliasome60MYA.HugediversityofmarsupialsinAustraliasupportsthehypothesisthat:evolutionisinfluencedbythemixof ntsandanimalsinaparticularcontinentAnatomicalVertebrateAllcontainthesamesetsofbonesinsimilarButmodifiedextensivelytomeetvariousadaptivesupportthehypothesisofcommon

Althoughthespecificdesigndetailsofvertebratef