Population structure

Population structure - are present the same species (...

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Population structure: are populations the unit of evolution? (Ehrlich and Raven 1969, Science 165:1288-1232) Species are just "phenetic clusters". But why do populations cluster into "species". Checkerspot butterfly studied on Jasper Ridge near Stanford CA by Paul Ehrlich and colleagues (1975 Science 188:221-228). Different populations fluctuate independently: suggests little gene exchange between populations (But Slatkin's analysis of allele frequency data suggest otherwise. Geographic variation in reproductive isolation. If a series of populations can mate sequentially, but the end populations cannot, is one species two?? Mayr would say that since they do not meet the issue is not biologically relevant. Do you agree? Polymorphism. Mimicry complexes of African swallowtail. Papilio dardanus exists as one morph where no noxious species are found (Madagascar). Where noxious models
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Unformatted text preview: are present the same species ( Papilio dardanus ) takes on different forms depending on the local model; the mimetic forms look like completely different species but are one. Sibling species . Morphologically indistinguishable, but are reproductively isolated. Not always easy to test for reproductive isolation and no morphological grounds on which to separate populations. Descriptions of the geography of population location/overlap helps focus on how geography might influence gene flow . If gene exchange between two populations is completely stopped, what will happen? Allopatric populations/species exist in different areas (do not overlap or abut); sympatric populations/species occupy the same geographic locality; parapatric populations/species have abutting but not overlapping ranges; a peripatric distribution refers to peripheral isolates....
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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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