Speciation

Reproductive courtship behavior is an example of a

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Unformatted text preview: iming. reproductive Courtship behavior is an example of a behavioral barrier behavioral Mechanical isolation: Female and male sex Mechanical organs or gametes are not compatible organs Gametic isolation: After copulation, gametes Gametic do not unite to form a zygote do • Postzygotic barriers operate after hybrid zygotes are Postzygotic formed formed Hybrid inviability: Hybrids do not survive Hybrid sterility: Hybrid offspring between two Hybrid species are sterile and therefore cannot mate species Hybrid breakdown: Hybrids that mate with each Hybrid other or either parent species produce feeble or sterile offspring sterile Horse Horse Donkey Mule - sterile MECHANISMS OF SPECIATION MECHANISMS Geographic isolation can lead to speciation In allopatric speciation, a population is In geographically divided geographically • Barriers include geologic processes such as Barriers emergence of a mountain or subsidence of a lake emergence • Changes in allele frequencies are unaffected by gene Changes flow from other populations flow • New species often evolve, but only after reproductive New barriers develop barriers A....
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This document was uploaded on 02/26/2014 for the course ENG 102 at Maryland.

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