ANTHRBIO 201 Chapter Notes - Chapter 1: Molecular Clock, Evolvability, Phanerozoic
13 Sep 2016
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Document Summary
Cambrian explosion- rapid diversification of animals is likely a mixture of biotic and abiotic processes. 3 main hypotheses for the cambrian explosion. Molecular clocks and the fossil record indicate that more than 100 extant animal phyla and classes appeared in the cambrian but only a few date to before the cambrian. Animals with longitudinal plane of symmetry, and specialized internal organ systems. Complex food webs were also a driver for diversification and an indicator within the fossil record that the cambrian explosion was well under way. Induced an arms race that would account for such incredible diversity. Abiotic processes as a possible cause of the cambrian explosion have been looked at recently. Erosion resulted in low relief continental interiors with extremely weathered crystalline basement rock, there was also major sea level rise, leading to flooding, extensive erosion, and massive land slides into other oceans, Increase in calcium concentration directly facilitated the origin of biomineralization.
