BIOLOGY 171 Study Guide - Midterm Guide: Radioactive Decay, Radionuclide, Ovule
28 Mar 2019
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Process of fossilization: quick burial (by sentiments) two main types of fossils, body fossils: direct evidence of organisms no decomposition/ slow decomposition, bones, teeth, skulls, vertebrae, and shells, organisms persevere in ice/ amber, petri ed wood. Fossilized pollen/ fossil fungal spores: trace fossils: indirect evidence of organism"s activities footprints, tracts, burrows, coprolites (fossilized poop), chemical fossils. Radioactive decay and geological dating: half life: half life is the amount of time it takes for a radio isotope to decay and produce 50% of the daughter isotope. Hadean eon: earth forms: 4. 5 bya liquid water- about 4. 3 bya. First cells: prokaryotes: chemical signs 3. 8 bya. Rst bacteria 3. 5 bya: photosynthesis (cyanobacteria, 3. 5 bya) Proterozoic eon (2. 5 bya to 542 mya: atmosphere and ocean surface are oxygenated, 2. 4 bya, oxygen catastrophe, a mass extinction event. First multi cellar eukaryotic fossil (scientist think its a species of red algae) 1 bya.
