Bio Exam 2 review - All of the genes in a population...

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All of the genes in a population constitute a gene pool With regard to population genetics, a population is defined as a group of individuals of the same species that can interbreed with one another Polymorphism refers to a genotype or phenotype that is found in two or more forms in a population, a monomorphic gene exists predominantly as a single allele in a population An allele frequency is the number of copies of an allele divided by the total number of alleles in a population, while a genotype frequency is the number of individuals with a given genotype divided by the total number of individuals The Hardy-Weinberg Equation relates allele and genotype frequencies Microevolution involves changes in a population’s gene pool from one generation to the next The sources of new genetic variation are random gene mutations, gene duplications, exon shuffling, and horizontal gene transfer. This variation is acted upon by natural selection, genetic drift migration and nonrandom mating to alter allele and genotype frequencies and ultimately cause a population to evolve over many generations Natural selection favors individuals with the greatest reproductive success. Darwinian fitness is a measure of reproductive success. The mean fitness of a population is its average reproductive success. Directional selection is a form of natural selection that favors one extreme of a phenotypic distribution Stabilizing selection is a second form of natural selection that favors an intermediate phenotype Disruptive selection is a third pattern of natural selection that favors two or more genotypes. An example is when a population occupies a diverse environment
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Balancing selection maintains a balanced polymorphism in a population. Examples include heterozygote advantage and negative frequency-dependent selection Sexual selection is directed at traits that make it more likely for individuals to find or choose a mate and/or engage in successful mating. This can lead to traits described as secondary sexual characteristics Seehausen and can Alphen discovered that female choice in mates in cichlids is influenced by male coloration. This is an example of sexual selection
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