BILD 3 Study Guide - Final Guide: Radiometric Dating, Pleistocene Megafauna, Neanderthal
15 Mar 2019
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2 half-lives, is remaining, and 3 half-lives, there is. 1/8 remaining: given the half-life of a radioactive isotope, you should be able to roughly estimate how much of it would be left after a given number of half-lives, ex: half life is 500 years--> 1hf=50%, 2hf=25%, 3hf=12. 5%, 4hf=6. 25: explain how carbon in the atmosphere sets the carbon- 14/carbon-12 ratio during an organism"s lifetime: when an organism dies, it stops accumulating carbon-12. 2700bya: cause: photosynthesis of cyanobacteria, effect: increase in atmospheric oxygen; anaerobic organisms (those that can"t harness oxygen) died off; those that used oxygen became more and more common, evidence: ?, endosymbiosis and the origin of eukaryotes. Bacterium then becomes an organelle in the cell (i. e the mitochondrion): relationship was mutually beneficial for both the cell and bacterium (ex: bacterium could have been anaerobic in a world that was becoming more aerobic), evidence: Mitochondria and plastids replicate by a splitting process similar to many prokaryotes.
