Ch.25 - Ch.25 -The History of the Life on Earth Wednesday,...

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Ch.25 -The History of the Life on Earth Wednesday, January 28, 2009 1:45 PM Lecture Topic: 1. Early Earth a. Earth is about 4.6 billion years old b. Life arouse about 3.8 billion years ago i. Chemical traces in rocks 3.8 BY ii. Fossil bacteria in rocks 3.5 BY c. No spontaneous generation now, but must have happened then 2. Conditions on Early Earth a. Atmosphere i. CO 2 ,CH 4 ,NH 3 ,H 2 S,H 2 O 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 3. Testable hypotheses explaining the origin of life a. Abiotic synthesis of small organic molecules b. Joining these molecules into polymers c. Packaging these molecules into "protobionts" d. The origin of self-replicating molecules 4. a. Figure 4.2 5. Alternative hypotheses a. First organic compounds may have been synthesized near hydrothermal vents b. Extraterrestrial origin 6. Abiotic synthesis of Polymers a. Small organic molecules polymerize when they are concentrated on hot sand or clay 7. Protobionts a. Aggregates of abiotically produced molecules surrounded by a membrane
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This note was uploaded on 02/28/2009 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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Ch.25 - Ch.25 -The History of the Life on Earth Wednesday,...

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