BIOL 1001 Lecture Notes - Lecture 21: Hybrid Zone, Reproductive Isolation, Character Displacement
13 Jul 2017
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Duration of isolation determines if the division between species is permanent. It takes time for mutation, natural and sexual selection, drifto cause a change in the gene pool. Small populations result in faster rate of speciation. Lecture 21- speciation: re-contact and isolation- textbook 103-108. Possibilities under re-contact: not enough divergence in time gene pools merge, pre-zygotic barriers have evolved result in speciation, post zygotic barriers have evolved in time speciation occurs with some hybridization, hybrid zone, character displacement. If the divergence genetically s strong enough, the hybrid offspring will have low fitness. Ns selects to reproductively isolate these hybrids since they have lower fitness. Zone when two species come into contact after isolation period and the population shows mixed traits. If zone is stable then the hybrids have low fitness. Sister species in sympatry are unwilling to mate with one another. Offspring wont be adapted to a specific environment. Start competing with the hermit warbler males for the.
