BIO 2129 Lecture Notes - Lecture 18: Species Richness, Glacial Motion
25 Nov 2016
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Document Summary
Why there are more species in tropical than in cold areas. Large number of birds in like brazil and africa and stuff. Annual climatic stability is hypothesized to create two phenomena. Towards tropical areas, the geographical range of species becomes smaller. Eg things in canada have large geographical distribution. Need to be able to tolerate a range of temperature. Can fit more species in one place because range is small. Organisms that avoid the weather are not expected to follow it (excludes exotherms) or show latitudinal gradients of diversity. Other taxa do not exhibit the latitudinal gradients should also not follow rapoport"s rule. Annual climatic variability that indirectly causes species diversity. Can arise or be magnified as a sampling artifact (less tropical sampling leads to apparent small ranges) Much of north america was glaciated/inundated during the wisconsinan. At the moment we are just leaving a glacial peiod, around 10,000 years ago.
