Lecture Notes July 6

Lecture Notes July 6 - -within 40 million years ago, almost...

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July 6, 2009 Timeline for Life on Earth - 4 major eons o hadean- formation of earth, primordial soup and protobionts o archaen- origin of life, radiation of prokaryotes o proterozoic- origin and radiation of eukaryotes o phanerozoic- radiation and diversification of multicellular organisms o hadean + archaen + proterozoic = precambrian - 3 major divisions of life o bacteria o archea o eularya (plants/ animals/ etc) Major Events of Precambrian - origin and radiation of prokaryotes o photosynthesis- new metabolic pathway o increased levels of O 2 in atm - origin and radiation of eukaryotes - first simple multi-cellular organisms Major Events of Paleozoic - cambian explosion - 1 st vertebrates, fishes diversify - invasion of land animals (invertebrates) - extensive fern forests (make today’s coal and oil deposits) - 1 st amphibians, reptiles, insects - 1 st gymnosperms (confers [naked seeds]) - Permian extinction (biggest mass extinction; 90% of life) Cambrian Explosion - rapid appearance and diversification of phyla at start of Paleozoic period - 565 million years ago- multicellular animals appear
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Unformatted text preview: -within 40 million years ago, almost all major animal phyla appear-3 fossil deposits shed light on this sequence of events o Duoshanto fossils S. China 580-570 mya microscopic fossils (tiny sponges and embryos of animals) likely all filter feeders o Eidacaran Fossils S. Australia 560-540 mya sponges, jellies, comb jellies, burrows and tracts of worm like animals no hard shells, limbs or heads with appendages o Burgess Shale Fossils British Columbia 525- 515 mya abundant sponges, jellies, comb jellies broad new animals with eyes mouths limbs shells and feeding appendages almos all modern phylia present Major events of Eesozoic-first dinos, mammals-gymnosperms radiate-dinos radiate-first angiosperms-mass extinctions at end of cretaceous Major events of Cenozoic-radiation of angiosperms and insects (coevolution)-radiation of mammals-appearance of hominids...
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Lecture Notes July 6 - -within 40 million years ago, almost...

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