10-4 History of Life on Earth 2

10-4 History of Life on Earth 2 - 9/30/2010 1 Cornelius W....

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Unformatted text preview: 9/30/2010 1 Cornelius W. Sullivan, Ph.D. Professor AHF 209F [email protected] Office Hours M&W 11:30am to 12:30pm Chapter 25 Part II Summary part I • Conditions on the early earth made the origin of life possible • The fossil record documents the history of life • Key event in life’s history include the origins of single celled organisms Fig. 25-4i Stromatolites 9/30/2010 2 Fig. 25-4j Fossilized stromatolite The dating game • Depends on radiometric dating methods • Radioactive isotopes • Half life Carbon-14 5,730 yrs good to 75,000 yrs Uranium 238yrs 4.5 billion years Strata- Rock sandwich Fig. 25-5 Time (half-lives) Accumulating “daughter” isotope Remaining “parent” isotope 1 2 3 4 1 / 2 1 / 4 1 / 8 1 / 16 Prokaryote to Eukaryote • Evolution after more than 2 byrs and then over ~ 2 byrs • Serial endosymbiosis • Eukaryote single celled to Multi-cellular Eukaryotes 9/30/2010 2 Fig. 25-4j Fossilized stromatolite The dating game • Depends on radiometric dating methods • Radioactive isotopes • Half life Carbon-14 5,730 yrs good to 75,000 yrs Uranium 238yrs 4.5 billion years Strata- Rock sandwich Fig. 25-5 Time (half-lives) Accumulating “daughter” isotope Remaining “parent” isotope 1 2 3 4 1 / 2 1 / 4 1 / 8 1 / 16 Prokaryote to Eukaryote • Evolution after more than 2 byrs and then over ~ 2 byrs • Serial endosymbiosis • Eukaryote single celled to Multi-cellular Eukaryotes 9/30/2010 3 Evolution that changed the...
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10-4 History of Life on Earth 2 - 9/30/2010 1 Cornelius W....

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