BIOL 1001 Lecture Notes - Lecture 38: Ocean Acidification, Polytomy, Exaptation
26 Mar 2017
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Document Summary
Rates of origin & extinction of species shape history of life. Population grows is birth rate is greater than deaths. Population decreases when death rate is greater than births. Over the course of earths history- normal rates of origination & extinction of species closely parallel each other. This is due to selective pressures & natural selection. Clade can only survive extinction by producing new species. Mass extinctions: large number of lineages (60%) of species have gone extinct. They are driven by cataphoric or sudden changes in environment. No species or characteristics are better adapted to such events. Calcium carbonate is necessary for reef corals & shell organisms. This is necessary for species growth of organism. If these certain organisms went extinct that rely of calcium carbonate, it will cause a cascade event for other organisms that rely on those organisms. Adaptive radiation: rapid speciation & ecological diversification within a single lineage.
