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Biology chapt 16

Biology chapter 16

TermDefinition
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
Created by: Haleyannestes