8 - BIO LECTURE NOTES (1/23/09) Geological time scale o...

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BIO LECTURE NOTES (1/23/09) Geological time scale o Origin of earth – 4.6 billion years ago o Earth cools and crust solidifies – 4 billion years ago o First evidence of life/origin of life – 3.6 billions years ago o Oldest prokaryotic fossils – 3.5 billion years ago o Accumulation of oxygen in the atmosphere – 2.5 billion years ago o Origin of eukaryotes – 2 billion years ago o Oldest eukaryotic fossils – 1.7 billion years ago o Origin of multicultural organisms – 1 billion years ago o Oldest animal fossils – 750 million years ago o Plants and fungi colonize land – 440 million years ago o Extinction of dinosaurs – 60 million years ago o First humans – 100, 000 years ago Three domains of life o Bacteria o Archaea o Eukarya o What is life? Life can be defined as a self-sustained chemical system capable of undergoing Darwinian evolution How did life on earth begin? o Through natural chemical processes that we can investigate scientifically o From outer space o Through special creation by divine entity How do we study the origins of life? o
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This note was uploaded on 11/16/2009 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.

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8 - BIO LECTURE NOTES (1/23/09) Geological time scale o...

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