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Biology chapt 16
Biology chapter 16
Term | Definition |
---|---|
population | Group of organisms of the same species occupying a certain area and sharing a common gene pool. |
microevolution | Change in gene frequencies between populations of a species over time. |
population genetics | The study of gene frequencies and their changes within a population. |
gene pool | Total of the alleles of all the individuals in a population. colonization by a limited number of individuals who, by chance, have different genotype and allele frequencies than the parent population. |
hardy-Weinberg principle (equilibrium) | Mathematical law stating that the gene frequencies in a population remain stable if evolution does not occur due to nonrandom mating, selection, migration, and genetic drift. |
Hardy- Weinberg principle applies: | No mutation, No migration, Large gene pool, Random mating, No selection. |
gene flow | Sharing of genes between two populations through interbreeding. |
genetic drift | Mechanism of evolution due to random changes in the allelic frequencies of a population; more likely to occur in small populations or when only a few individuals of a large population reproduce. |
reproductively isolated | Descriptive term that indicates that a population is incapable of interbreeding with another population. |
bottleneck effect | Type of genetic drift; occurs when a majority of genotypes are prevented from participating in the production of the next generation as a result of a natural disaster or human interference. |
founder effect | Cause of genetic drift due to |
inbreeding | Mating between closely related individuals; influences the genotype ratios of the gene pool. |
nonrandom mating | Mating among individuals on the basis of their phenotypic similarities or differences, rather than mating on a random basis. |
assortative mating | Mating of individuals with similar phenotypes. |
Polygenic | Many traits are this and controlled by many genes. |
stabilizing selection | Outcome of natural selection in which extreme phenotypes are eliminated and the average phenotype is conserved. |
directional selection | Outcome of natural selection in which an extreme phenotype is favored, usually in a changing environment. |
disruptive selection | Outcome of natural selection in which the two extreme phenotypes are favored over the average phenotype, leading to more than one distinct form. |
sexual selection | Changes in males and females, often due to male competition and female selectivity, leading to increased fitness. |
fitness | Ability of an organism to reproduce and pass its genes to the next fertile generation; measured against the ability of other organisms to reproduce in the same environment. |
sexual dimorphism | Species that have distinct differences between the sexes, resulting in male and female forms. |
cost-benefit analysis | A weighing-out of the costs and benefits (in terms of contributions to reproductive success) of a particular strategy or behavior. |
dominance hierarchy | Organization of animals in a group that determines the order in which the animals have access to resources. |
territory | Area occupied and defended exclusively by an animal or a group of animals. |
territoriality | Marking and/or defending a particular area against invasion by another species member; area often used for the purpose of feeding, mating, and caring for young. |
heterozygote advantage | Situation in which individuals heterozygous for a trait have a selective advantage over those who are homozygous dominant or recessive; an example is sickle-cell disease. |
Hardy- Weinberg equation | p^2+2pq+q^2 |