| Term | Definition |
|---|
| population | group of individuals of the same species that interbreed |
| gene pool | all genes, including all the different alleles, present in a population |
| relative frequency | of an allele is the number of times the allele occurs in a gene pool (%) |
| Evolution | _________ is the change in relative frequency |
| heritable variation | inherited differences of an individual mutations and genetic shuffling that results from sexual reprduction |
| mutations | change in a sequence of DNA; mistakes in DNA replication, radiation or chemicals; don't always affect |
| gene shuffling | heritable differences; crossing-over; sexual reproduces causes differnt phenotypes of individuals, does not change relative frequencies of alleles in population |
| number of genes that control the trait | determines the numbers of phenotypes for a given trait |
| single-gene trait | controlled by one gene that has two alleles; only two possible phenotypes |
| phenotypic ratios | determined by frequency of alleles and dominance or recessive |
| polygenic traits | two or more genes control trait [ex: human height] |
| individuals, populations | ___________ don't evolve, ___________ do |
| natural selection | organisms with highest fitness will reproduce |
| directional selection | one end of the curve higher fitness than middle or the end; phenotypes shifts towards higher end |
| stabilizing selection | center of the curve higher finess ends of the curve; center stays and ends narrow |
| disruptive selection | ends higher fitness than middle; reason for speciation (graphs separate) --> 2 phenotypes created |
| genetic drift | random change in allele frequency |
| founder effect | allele frequencies change due to migration of a small subgroup |
| Hardy-Weinberg principle | allele frequencies in a populations remain constant [genetic equilibrium] unless one or more factors cause those frequencies to change |
| maintain genetic equilibrium | random mating; large population; no movement into or out of the population; no mutations; no natural selection |
| speciation | formation of new species |
| species | breed and produce fertile offspring |
| behavioral isolation | differences in courtship rituals or other reproudcive strategies that involve behavior |
| geographic isolation | populations separated by geographic barness such as rivers or mountains |
| temporal isolation | species reproduce at different times |
| reproductive isolation | when members of two populations cannot interbreed and produce fertile offspring |
Combine with other sets
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