07-07-08

07-07-08 - 07-07-08 Ch. 26 The Tree of Life: An...

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07-07-08 Ch. 26 The Tree of Life: An introduction into Biological diversity A. Early Earth a. Earth is about 4.6 billion years old i. Radiometric dating of meteorites and moon rocks b. Life arose about 3.8 Billion years ago i. Chemical traces in rock about 3.8 billion years old ii. Fossil bacteria in rocks 3.5 billion years old c. No spontaneous generation now, but must have happened then B. Conditions on Early Earth a. Atmosphere i. CO2, CH4, NH3, H2S, H2O ii. No free oxygen b. Abundant energy to drive reactions i. Frequent storms with much lightening ii. Frequent volcanic eruptions iii. Frequent meteor impacts iv. UV light from the sun C. Testable Hypotheses that help explain the origin of life a. A biotic synthesis of small organic molecules b. Joining these molecules into polymers c. Packaging these molecules into “protobionts” d. The origin of self-replicating molecules D. Miller and Urey experiment a. Fig 26.2 E. Alternative Hypotheses
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a. First organic compounds may have been synthesized near hydrothermal vents
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07-07-08 - 07-07-08 Ch. 26 The Tree of Life: An...

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