古生物學(xué)-演化階段

MainstagesofbiologicalevolutionEvolutionarystagesOncethelifeappeared,itenteredthestageofbio-evolution,thechemicalevolutionwasterminated.Inthelongprocessoflifeevolution,thebiologicalevolutionwasstepbystep.生命演化的階段性

ChemicalevolutionEarliestfossilrecordsFreeoxygenaccumulationBigexplosionMainstagesSpiderNautilusChimp-anzeeCrocodileFossilrecordsofearlylife

（早期生命的化石證據(jù)）WarrawoonaGroup（WAustralia，3.5billionyears）Characters:filament-likeorradiates,mono-cellspheres,belongingtobacteria.SuchasSulphur-bacterium(琉細(xì)菌)、Pigmentedglidingbacteria（色素滑細(xì)菌）、Cyanobacteria（藍(lán)細(xì)菌）OnverwachtGroup（earliestlifeforms）（S.Africa，3.5billionyears）Archaeosphaeroidesbarbertonensis（巴伯頓古球菌）（Proto-cell,原細(xì)胞？）(根據(jù)對碳?xì)浠衔锏挠袡C(jī)地球化學(xué)分析)FigTreeGroup（S.Africa，3.1~3.2billionyears）Eobacteriumisolatum（等稱原始細(xì)菌）inblackchert，withtwo-layermembrane(膜)structure,possiblywiththeearliestorganforphotosynthesis.Withchlorophyll(葉綠素)init.FortescueGroup（WAustralia，2.8billionyears）Silk-likeprokarytoainstromatolites

（疊層石），unbranched，withreproductivesegments。Withoutnucleus。GunflintFormation（Canada，1.95billionyears）Eukaryota（真核生物）:Animikiea、Gunflintia、Eoastrion、Kakabekiaunabellata。Bulealgaeflurished，theyweremajorproducersinsea。Star-likealgae，comparablewithsomepresentfreshwaterforms，indicatingthesalinitywasabout5~10‰insea

Micro-florafromChangzhougouFm(Hebei，1.9billionyearsago）Characters:relativelylargeinsize(generallyitsdiameter>40m，themaximumupto300m。Occurrenceofleaf-likeforms,theyaretypicalstructuresoflowerplants.Withecologicaldiversity,whichwaspreparedforadaptingenvironmentalchangeBungleBungleDolomite（WAustralia，1.6billionyears）Characters：dominatedbyeukaryota（真核生物，algae），manyleaf-likeforms（a）。Atsametime，withbluealage（prokaryota原核生物（b-e）。McMinnFm（NAustralia，1.4billionyears）Characters:Sphericalone-cell,therearesomedensematters,whichmightbesomethinglikenuclei.BitterSpringsFm（CentralAustralia，0.9-1billionyears)Characters:withrealnucleus,cell-wallandcytoplasm(細(xì)胞質(zhì)):Gleno-botrydionaenigmatis(幽葡萄藻）Tracefossilofmetazona（India，1billionyear）Weng’anFauna（Guizhou，600millionyears）LatePrecambrianDuoshantou

phosphorites，withmetazoan（multicellularanimal，后生動(dòng)物）embryospreservedinearlycleavagestages借助同步加速器輻射顯微X線斷層攝影術(shù)，科研人員重構(gòu)了這種胚胎的三維圖像WilpenaPoundFm（EndofPrecambrian，0.54billionyearsago），SouthAustraliaPrecambrian

Ediacaranfauna（埃迪卡拉動(dòng)物群）Precambrian

EdiacaranfaunaPrecambrian

Ediacaranfauna

Myllokunmingia昆明魚

Haikouichthys海口魚ChengjiangFauna,Yuanan,EarlyCambrian,0.53billionyearsago這種動(dòng)物是一種食蟲哺乳動(dòng)物（真哺乳亞綱動(dòng)物擁有三顆臼齒，五顆前臼齒），重約15到17克，大小和一只鼩鼱差不多。它的前肢結(jié)構(gòu)表明，它是攀援高手。因此，我們認(rèn)為它是一種在樹上生活的食蟲哺乳動(dòng)物，靠捕蟲為生（1.6億年前）Juramaiasinensis

PaleozoicMesozoicCenozoicPrecambrian

3、Conclusions（keypoints）(1)Maincontentsoftheoreticalevolution:evolutionarymodelandmechanism,withthreelevels:microevolution,speciationandmacroevolution.(2)Massextinctionhaseitherterrestrialorextra-terrestrialcauses,theterrestrialcausesaremoreimportant

3、Conclusions（keypoints）(3)Essenceoflife:Lifeisasystemwithfunctionsofmetabolismandgeneticreproduction.Theoriginoflifeisachievedthroughthechemicalevolution.(4)Bio-evolutionisstepbystep,thegeneraltrendisfromlowertohigher,fromsimpletocomplexandfromseatoland.Thedominateddirectionofbio-evolutionisprogressiveingeneral.3、Conclusions（keypoints）(5)Theoriginoflifeandearlybio-evolutionunderwentaverylongprocessingeologicalhistory,thefossilrecordsareverylimited.