Ch 23 Evolution of populations
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eagleswings59 Plus on April 23, 2012
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33 terms
Terms | Definitions |
|---|---|
 Gregor Mendel | Father of genetics. Experimented with pea plants and discovered law of dominance, ind. assortment, and segregation. |
| population genetics | The study of genetic changes in populations; the science of microevolutionary changes in populations. |
| modern synthesis | a comprehensive theory of evolution that incorporates genetics and includes most of Darwin's ideas, focusing on populations as the fundamental units of evolution. |
| population | a group of organisms of the same species populating a given area |
| species | group of similar organisms that can breed and produce fertile offspring |
| gene pool | combined genetic information of all the members of a particular population |
| Hardy Weinberg Theorem | An axiom maintaining that the sexual shuffling of genes alone cannot alter the overall genetic makeup of a population. |
| Hardy Weinberg equilibrium | condition that occurs when the frequency of alleles in a particular gene pool remain constant over time |
| Hardy Weinberg equation | helps calculate frequencies of alleles in a population; pp+2pq+qq; p is the dominant allele; q is the recessive allele |
| microevolution | evolution resulting from small specific genetic changes that can lead to a new subspecies |
| genetic drift | The gradual changes in gene frequencies in a population due to random events |
| bottleneck effect | Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population. |
| founder effect | when a few individuals become isolated from a larger population, this smaller group may establish a new population whose gene pool isn't reflective of the source population |
| natural selection | the principle that, among the range of inherited trait variations, those that lead to increased reproduction and survival will most likely be passed on to succeeding generations |
| gene flow | movement of alleles into or out of a population due to the migration of individuals to or from the population |
| mutations | Random errors in gene replication that lead to a change in the sequence of nucleotides; the source of all genetic diversity |
| polymorphism | (biology) the existence of two or more forms of individuals within the same animal species (independent of sex differences) |
| gene diversity | measures the average percentage of gene loci that are heterozygous |
| nucleotide diversity | comparing the nucleotide sequences of DNA samples from two individuals then pooling the data from many such comparisons of two individuals |
| geographic variations | Differences between the gene pools of separate populations or population subgroups. |
| cline | a graded change in a character along a geographic axis |
| diploidy | The state or condition of being diploid (having each chromosome in two copies per nucleus or cell) |
| balanced polymorphism | The ability of natural selection to maintain diversity in a population. |
| frequency-dependent selection | a decline in the reproductive success of individuals that have a phenotype that has become too common in a population |
| neutral variations | Genetic diversity that confers no apparent selective advantage. |
| Darwinian fitness | The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals. |
| relative fitness | The contribution of one genotype to the next generation compared to that of alternative genotypes for the same locus. |
| directional selection | form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve |
| diversifying selection | Natural selection that favors extreme over intermediate phenotypes. |
| stabilizing selection | Natural selection that favors intermediate variants by acting against extreme phenotypes |
| sexual dimorphism | A special case of polymorphism based on the distinction between the secondary sex characteristics of males and females. |
| intrasexual selection | A direct competition among individuals of one sex (usually the males in vertebrates) for mates of the opposite sex. |
| intersexual selection | Selection whereby individuals of one sex (usually females) are choosy in selecting their mates from individuals of the other sex; also called mate choice. |
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