Biology 1001A Chapter Notes - Chapter 20: Evolutionary Taxonomy, Mosaic Evolution, Convergent Evolution
14 Dec 2015
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Fossils are found in sedimentary rock in distinctive strata/layers arranged in order from oldest (bottom) to youngest (highest) Sometimes, strata can be disrupted due to geological processes. Stratum represents organisms that lived and died in the past. Sequence of strata used to establish geological time scale that diagrams the history of life on earth. 20. 2 the fossil record: how fossils were formed. Fossils were formed from dissolved minerals entered the spaces within the bones and then solidified. Plant fossils are moulds or impressions compressed shortly after death, so 3d analysis is difficult. Few organisms fossilize completely; b/c some organisms are more likely to fossilize than others: early fossils. Stromatolites (1st fossil evidence) 3. 5 billion years ago (bya) Prokaryotes & plants (increased atmospheric oxygen) 2. 5 bya. Explosion in diversity of groups of organisms 600 mya: importance of skeletons. Explosion of life marked the beginning of cambrian coincides w/ appearance of skeletons.
