CASE HISTORIES OF SPECIATION I

CASE HISTORIES OF SPECIATION I - CASE HISTORIES OF...

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Some of the best examples of speciation are examples of diversification on archipelagos . These provide clear contexts of allopatry and hence provide the extrinsic barrier to gene exchange from the source (usually mainland) population. The most famous are the Galapagos Islands . The islands are young (some ~ 1 million years), have a volcanic origin providing an opportunity for new arrivals to "radiate" into open niches and the islands are quite distant from the mainland. This isolation and context of primary succession (e.g., development of a flora and fauna on a "clean slate") will allow for a random element in community composition. Irrespective of genetic consequences of the founding event, subsequent evolution of species quite likely will be under dramatically different selective regime than those in the source population. Darwin's Finches . Morphological and genetic studies indicate that they are derived from single ancestral finch, i.e., are monophyletic. There has been dramatic
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This note was uploaded on 11/06/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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