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Unformatted text preview: D ATE : 1/22/08 ISB N OTES History of life 1. Era – ex. year 2. Period – smaller break down of an era….ex. month 3. Epoch – smaller break down of a period…ex. Day First mammals? • Mesozoic era First human types? • 1.65 million years ago Modern humans? • Less than 100,000 years ago Hunters/gatherers? • About .01 million years ago Neolific revolution • Was the switch from hunting and gathering Dinosaurs died when? • Start of Cenozoic era • Mass radiations and then mass extinctions What caused these mass extinctions? • Global cooling caused most. • An asteroid caused the major one at the K-T boundary (dinosaurs) • Dinosaurs died, and mammals then flourished b/c of less competition How did these life forms arise? 1. Explanations are difficult • Not much hard evidence • Most explanations are speculative • Sugars and amino acids have been found in rocks from earth, the moon and meteorites from outer...
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- Spring '08
- Organic matter, Cretaceous–Tertiary extinction event, bacteria **Nitrogen fixation