Biology 3466B Study Guide - Final Guide: Phanerozoic, Cambrian Explosion, Multicellular Organism
9 Nov 2012
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Document Summary
Fossils are traces left by organisms of the past there are. Geological time scale is a hierarchy divided into eons, eras, periods, epochs and stages: compression: Organic material buried in sediment before decomposition leaving an impression in material below, from weight of the sediment: cast & model: Cast filled with new material and hardened into rock. These fossils preserve info about external and internal surfaces: permineralized: Structures buried in sediment and dissolved materials precipitate into the cell. These fossils preserve internal structure detail: unaltered remains: Preserved in environments that discourage loss from weathering. These fossils represent a small fraction of the fossil record, found in peat bogs, permafrost etc. Radioisotopes and accurate dating techniques allowed absolute time intervals to be assigned. Phanerozoic era beings with the cambrian explosion and ends in the present. Begins with radiation of animals, ends with mass extinction at the end of the permian: mesozoic (middle life): Age of reptiles beginning at the end of the.
