BIOL 1070 Lecture Notes - Lecture 8: Endemism, Overfishing, Allopatric Speciation
12 Oct 2016
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Document Summary
Global biodiversity is the net outcome of two opposing processes: diversification through speciation, loss of diversity through extinction. Endemism: it evolved here and that is why it is found there. Range expansion: conditions changed so they moved here. Range shift: eg: polar bears; there was no one filling that niche in the arctic so they evolved with white fur to blend in and fill the niche. Long-range dispersal/non-native/introduced/invasive: brought there by some reason. Vicariance: land has to move (eg: pangaea) which eventually changes: eg: you can go to antarctica and see remnants of it being a tropical region. People believed that an overpopulation of seals are eating lots of cod, leaving very few for fishers to catch. This led to a mass killing of seals (by humans) to try to get rid of competition.
