古生物学-演化阶段

MainstagesofbiologicalevolutionEvolutionarystagesOncethelifeappeared,itenteredthestageofbio-evolution,thechemicalevolutionwasterminated.Inthelongprocessoflifeevolution,thebiologicalevolutionwasstepbystep.生命演化的阶段性

ChemicalevolutionEarliestfossilrecordsFreeoxygenaccumulationBigexplosionMainstagesSpiderNautilusChimp-anzeeCrocodileFossilrecordsofearlylife

（早期生命的化石证据）WarrawoonaGroup（WAustralia，3.5billionyears）Characters:filament-likeorradiates,mono-cellspheres,belongingtobacteria.SuchasSulphur-bacterium(琉细菌)、Pigmentedglidingbacteria（色素滑细菌）、Cyanobacteria（蓝细菌）OnverwachtGroup（earliestlifeforms）（S.Africa，3.5billionyears）Archaeosphaeroidesbarbertonensis（巴伯顿古球菌）（Proto-cell,原细胞？）(根据对碳氢化合物的有机地球化学分析)FigTreeGroup（S.Africa，3.1~3.2billionyears）Eobacteriumisolatum（等称原始细菌）inblackchert，withtwo-layermembrane(膜)structure,possiblywiththeearliestorganforphotosynthesis.Withchlorophyll(叶绿素)init.FortescueGroup（WAustralia，2.8billionyears）Silk-likeprokarytoainstromatolites

（叠层石），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(细胞质):Gleno-botrydionaenigmatis(幽葡萄藻）Tracefossilofmetazona（India，1billionyear）Weng’anFauna（Guizhou，600millionyears）LatePrecambrianDuoshantou

phosphorites，withmetazoan（multicellularanimal，后生动物）embryospreservedinearlycleavagestages借助同步加速器辐射显微X线断层摄影术，科研人员重构了这种胚胎的三维图像WilpenaPoundFm（EndofPrecambrian，0.54billionyearsago），SouthAustraliaPrecambrian

Ediacaranfauna（埃迪卡拉动物群）Precambrian

EdiacaranfaunaPrecambrian

Ediacaranfauna

Myllokunmingia昆明鱼

Haikouichthys海口鱼ChengjiangFauna,Yuanan,EarlyCambrian,0.53billionyearsago这种动物是一种食虫哺乳动物（真哺乳亚纲动物拥有三颗臼齿，五颗前臼齿），重约15到17克，大小和一只鼩鼱差不多。它的前肢结构表明，它是攀援高手。因此，我们认为它是一种在树上生活的食虫哺乳动物，靠捕虫为生（1.6亿年前）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.