Chapter 26

Chapter 26 - Chapter 26 The Tree of Life: An Introduction...

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Chapter 26 – The Tree of Life: An Introduction to Biological Diversity 1) Early Earth a) Earth is about 4.6 billion years (BY) old i) Radiometric dating of meteorites and moon rocks b) Life arose about 3.4 BY ago i) Chemical traces in rocks 3.8 BY ii) Fossil bacteria in rocks 3.5 BY c) No spontaneous generation now 2) 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 w/ much lightening ii) Frequent volcanic eruptions iii) Frequent meteor impacts iv) UV light from the sun, No ozone layer 3) How to Assemble a Living Thing a) Abiotic synthesis of small organic molecules b) Joining these molecules into polymers c) Packaging these molecules into “protobionts”
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This note was uploaded on 02/04/2009 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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