BIO 200 Lecture Notes - Lecture 1: Cambrian Explosion, Cambrian, Snowball Earth
30 Aug 2016
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What do scientists rely on to recreate history: fossil record. Earth"s history is divided into: eons, eras, periods. Biota: assemblage of all organisms of all kinds living at a particular time or place. Flora: all of the plants living in a particular time or place. Several processes contribute to the paucity of fossils. When is it likely for an organism to become a fossil: if it"s transported by wind or water to a place that lacks oxygen. Plankton: small, floating organisms: eaten by slightly larger filter-feeding animals. It took billions of years for eukaryotes to diversify rapidly. High atmospheric and dissolved o2 concentrations were needed for what: to support large multicellular organisms. They came together to form large continents. Many groups of organisms that arose during the cambrian later diversified. What are the periods of the paleozoic era: ordovician, silurian, devonian, carboniferous, permian. What does each period represent: diversification of specific groups of organisms. Ordovician period: southern hemisphere, marine organisms.
