ANTHROP 3300 Lecture Notes - Lecture 3: Reproductive Isolation, Genetic Drift, Genetic Variation
9 Sep 2016
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Document Summary
Forces of evolution: these produce changes in population gene pools from one generation to the next, genetic variation = leads to population change/speciation. Random separation of gene pool through physical separation of one group from larger population. New group = not necessarily representative of original population. Narrows down variation within population; increases variation between populations. Micro vs. macroevolution: micro: changes in gene polls that do not result in new species, macro: changes in gene pools that result in new species, genera, families, etc, speciation. C. 2. interbreeding organisms which are reproductively isolated from other such groups. Postzygotic isolating mechanisms = after mating (hybrid sterility) C. 4. isolation: mate at different times; mating rituals) Selection against hybrids reinforces reproductive isolation via prezygotic isolating mechanism. Two groups reproduce low fitness hybrids natural selection will favor prezygotic isolating mechanism (never mate: allopatric speciation. Original population splits into two geographically isolated areas = new distinct species emerges after time and reproductively isolated: peripatric speciation.
