BIOL 0510 Lecture Notes - Lecture 8: Allan Hills 84001, Great Oxygenation Event, Isotope Fractionation
7 Nov 2016
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Document Summary
Purported microfossils from martial meteorite alh 84001 (4. 1 billion years old) thought to have formed when mars had liquid water on its surface. Water, but alternatives such as ammonia or methane have been hypothesized. Would there be a chirality bias as in aas and sugars. Darwin"s hypothesis 1871 about the location of the origin of life. Current hypothesis: probably got started deep in the ocean in hydrothermal vents. There is a thought that life evolved, was destroyed by impacts, and then arose again - suggests that when the conditions are right, you will get life. When o2 produced by photosynthetic bacteria began to accumulate in the atmosphere (0. 1% o2 level in atmosphere) Microfossils from 2 bya vs. similar modern species. Enzymes prefer substrates containing the lighter c isotope (12c) over heavy (13c) Compounds produced by biological processes will thus have less 13c than non-biological molecules.
