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10/17/2013
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EVOLUTIONBiology 145
Lecture 13 – Speciation
FOUNDER EFFECT
In a population with AA, Aa, and aa individuals, if ONE founds a subpopulation, it might well be a HOMOZYGOTE
Polydactyly –AmishAllele 1:14 versus 1:1000
General: 1:180,000PA Mennonites 1:176
Maple Syrup Urine Disease
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Genetic BOTTLENECKS
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SPECIATION
Gene flow must be interrupted!.
Anagenesis versus cladogenesis (speciation)
Chronospecies
Anageneticchange
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Allopatric speciation
Gene flow interrupted by a physical barrier
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Sciurus aberti aberti Sciurus aberti kaibabensis
Parapatric Speciation
Agrostis
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Sympatric speciation
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RIMS Reproductive Isolating Mechanisms
RIMS – pleiotropy
Food type
Song
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Ring species
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