BIOL 101 Lecture Notes - Lightning, Ammonia, Dinosaur (Disney'S Animal Kingdom)
30 Nov 2012
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Metabolism all the chemical reactions that go on inside a cell. Cyanobacteria photosynthetic prokaryotes that introduced oxygen to the earth"s atmosphere. Ozone layer formed 800 million years ago from accumulation of o2, gave uv protection. Miller-urey experiment: h, nh3, ch4, h2o in atmosphere and zapped with lightning. Spontaneous generation the idea that life arose from inanimate or decaying matter. Stromatolites rocklike structures formed by cyanobacteria, preserved in fossils. 3. 8 bya o2 first appears in atmosphere. 1. 5 bya o2 level at >1% of current. 600 mya o2 level at >5% of current level. Cambrian 542 mya o2 approach current levels. Most animal phyla present; diverse photosynthetic protists + cambrian explosion. Ordovician 488 mya glaciation, sea levels drop, max extinction (75%) clams. = two shells symmetrical, brachiopods = not, marine life radiated. Silurian 444mya sea levels rise; two continents form; plants and animals colonize land. Devonian 416mya age of fishes. Fishes diversify, first insects and amphibians; mass extinction (75%) first seed plants.
