古生物学-演化阶段.ppt

1、古生物学-演化阶段Evolutionary stagesnOnce the life appeared,it entered the stage of bio-evolution,the chemical evolution was terminated.In the long process of life evolution,the biological evolution was step by step.生命演化的阶段性Chemical evolutionEarliest fossil recordsFree oxygen accumulationBig explosionMain s

2、tagesSpiderNautilusChimp-anzeeCrocodileFossil records of early life（早期生命的化石证据）Warrawoona Group（W Australia，3.5 billion years）nCharacters:filament-like or radiates,mono-cell spheres,belonging to bacteria.Such as Sulphur-bacterium(琉细菌)、Pigmented gliding bacteria（色素滑细菌）、Cyanobacteria（蓝细菌）Onverwacht Gro

3、up（earliest life forms）（S.Africa，3.5 billion years）Archaeosphaeroides barbertonensis（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)Fig Tree Group（S.Africa，3.13.2 billion years）Eobacterium isolatum（等称原始细菌）in black chert，with two-layer membrane(膜)structure,possibly with the earliest organ for photosynthe

4、sis.With chlorophyll(叶绿素)in it.Fortescue Group（W Australia，2.8 billion years）nSilk-like prokarytoa in stromatolites（叠层石），unbranched，with reproductive segments。Without nucleus。Gunflint Formation（Canada，1.95 billion years）Eukaryota（真核生物）:Animikiea、Gunflintia、Eoastrion、Kakabekia unabellata。Bule algae f

5、lurished，they were major producers in sea。Star-like algae，comparable with some present freshwater forms，indicating the salinity was about 510 in sea Micro-flora from Changzhougou Fm(Hebei，1.9 billion years ago）nCharacters:relatively large in size(generally its diameter40m，the maximum up to 300 m。nOc

6、currence of leaf-like forms,they are typical structures of lower plants.nWith ecological diversity,which was prepared for adapting environmental changeBungle Bungle Dolomite（W Australia，1.6 billion years）nCharacters：dominated by eukaryota（真核生物，algae），many leaf-like forms（a）。nAt same time，with blue a

7、lage（prokaryota原核生物（b-e）。Mc Minn Fm（N Australia，1.4 billion years）nCharacters:Spherical one-cell,there are some dense matters,which might be something like nuclei.Bitter Springs Fm（Central Australia，0.9-1 billion years)nCharacters:with real nucleus,cell-wall and cytoplasm(细胞质):Gleno-botrydion aenigm

8、atis(幽葡萄藻）Trace fossil of metazona（India，1 billion year）Wengan Fauna（Guizhou，600 million years）nLate Precambrian Duoshantou phosphorites，with metazoan（multicellular animal，后生动物）embryos preserved in early cleavage stages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 Wilpena Pound Fm（End of Precambrian，0.54 bill

9、ion years ago），South AustraliaPrecambrian Ediacaran fauna（埃迪卡拉动物群）Precambrian Ediacaran faunaPrecambrian Ediacaran faunaMyllokunmingia昆明鱼Haikouichthys海口鱼Chengjiang Fauna,Yuanan,Early Cambrian,0.53 billion years ago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

10、活的食虫哺乳动物，靠捕虫为生（1.6亿年前）Juramaia sinensis PaleozoicMesozoicCenozoicPrecambrian 3、Conclusions（key points）n(1)Main contents of theoretical evolution:evolutionary model and mechanism,with three levels:microevolution,speciation and macroevolution.n(2)Mass extinction has either terrestrial or extra-terrest

11、rial causes,the terrestrial causes are more important 3、Conclusions（key points）n(3)Essence of life:Life is a system with functions of metabolism and genetic reproduction.The origin of life is achieved through the chemical evolution.n(4)Bio-evolution is step by step,the general trend is from lower to

12、 higher,from simple to complex and from sea to land.The dominated direction of bio-evolution is progressive in general.3、Conclusions（key points）n(5)The origin of life and early bio-evolution underwent a very long process in geological history,the fossil records are very limited.n(6)In recent years,there are many discoveries in paleontology,some key fossils that are very important in the study of evolution are found in China,some studies are standing at the front of world level.