BIOL 422 Lecture 2: Extinction Rates
5 May 2020
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Document Summary
Lifespan of fossil species: 1 - 10 million years. This means 0. 1 - 1 extinction per year per million species. Mass extinctions are often within 1000 - 10000 extinctions/yr. /mil. species. However it is harder to use older fossils to distinguish species from each other. Many taxa are missing in the fossil record. Octopi are a good example of species that do not fossilize well. There is a high concentration of nitrogen in their bodies which causes them to rot before the fossilize. Species = 0. 3 extinctions per year i. e. 1 extinction every 3 years not during a mass extinction event. Species = 0. 0055 extinctions per year i. e. 1 extinction every 182 years not during a mass extinction event. Since 1600 a. d. there have been 159 bird and 81 mammal extinctions. Birds are going extinct at 0. 40 species/year, compared to the est. of 0. 0099. Mammals are going extinct at 0. 20 species/year, compared to the est. of 0. 0055.
