ANTHR-140 Lecture Notes - Lecture 6: Population Bottleneck, Microevolution, Zygosity
15 Jun 2020
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Alleles confer bigger likelihood of survival to reproduce. Population bottleneck: population size reduced greatly and genetic diversity. Counteracts evolutionary forces that cause population to diversify. Interbreeding: increase frequency homozygous genotypes @ loci. Decrease frequency of heterozygous genotype @ loci. Negative am: increase freq of heterozygous geno @ loci (short vs tall) Positive am: increase freq of homozygous geno @ loci (blonde and blonde) Biological species concept (bsc): species is a group of interbreeding populations that are reproductively isolated from other groups. Pre mating mechanism: habitat isolation, temporal isolation, behavioral isolation, mechanical incompatibility. Post mating mechanism: sperm-egg incompatibility, non-viability of zygote- fetus or offspring, offspring sterility (mule) Recognition species concept: emphasises unique traits or behaviors that allow members of the same species to recognize when they want to mate with each other. Ecological species concept: exploiting a single ecological adaptation. Species that live together in the same habitat must have different niches. Adaptive radiation: single organism diversifies into many species.
