Ch54-2 - Character Displacement Character displacement is a...

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1 Character Displacement Sympatric Vs allopatric is a tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species Sympatric VS Allopatric speciation Sympatric Speciation VS Allopatric speciation Sympatric Speciation In sympatric speciation, a reproductive barrier isolates a subset of a population without geographic separation from the parent species Sympatric speciation can result from sexual selection Allopatric speciation In allopatric speciation, geographic isolation restricts gene flow between populations Reproductive isolation may then arise by natural selection, genetic drift, or sexual selection in the isolated populations Even if contact is restored between populations, interbreeding is prevented Sympatric Speciation 200 years ago, the ancestors of laid their eggs on Hawthorn flies generally end up mating with other hawthorn flies (which were introduced to America by immigrants. Domestic apple flies generally end up mating with other apple flies. Character Displacement Character displacement Hawthorns Apples Domestic Apples apple maggot flies only hawthorns. Domestic apples Allopatric Sympatric
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2 This means that gene flow between parts of the population that mate on different types of fruit is reduced. Allopatric speciation Character displacement characteristics become more divergent in sympatric populations of two species than in allopatric populations of the same two species Predation Isolation might occur because of great distance or a physical barrier, such as a desert or river. Speciation by geographic isolation is Two or more groups don’t mate with each other regularly, eventually causing that lineage to speciate. Fig. 54 4 Humming bird diversity allopatric speciation. . An example is variation in beak size between populations of two species of Gal pagos finches Character displacement is when Los Hermanos Beak depth Daphne , allopatric , allopatric Sympatric populations Santa María, San Cristóbal Beak depth (mm) Percentages of individuals in each size class
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This note was uploaded on 10/21/2009 for the course BIOL 6C taught by Professor Sundram during the Spring '09 term at DeAnza College.

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Ch54-2 - Character Displacement Character displacement is a...

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