| A | B |
|---|
| allele frequency | relative abundance of an allele of a gene within a population, expressed as a percentage |
| carrying capacity | ppulation size that an environment can sustain |
| demography | statistical study of populations |
| directional selection | natural selection that causes the frequency of a particular allele to move in one direction |
| dispersion | the pattern of distribution of organisms in a population |
| disruptive selection | natural selection in which individuals with extreme forms of a trait have an advantage |
| exponential growth curve | J-shaped curve showing the rapid increase in an exponentially growing population |
| gene flow | movement of alleles into or out of a population due to the migratioin of individuals to or from the population |
| genetic drift | random change in allele frequency in a population |
| genetic polymorphism | genetic variation in a population that results from more than one allele for a gene |
| Hardy-Weinberg principle | principle stating that the frequency of alleles in a population does not change unless evolutionary forces such as selection act on the population |
| K-strategist | species characterized by slow maturation, low fertility, slow population growth, and high competitive ability |
| logistic model | model of population growth that assumes finite resource levels limit population growth |
| model | generalized, hypothetical description of a system, such as a population, used to analyze or explain the system |
| nonrandom mating | mating between individuals of the same genotype |
| normal distribution | bell-shaped curve that results when the values of a trait in a population are plotted against their frequency |
| polygenic trait | characteristic of an organism that is influenced by several genes |
| population | group of individuals that belong to the same species, live in the same area, and breed with others in the group |
| population density | the number of individuals in a given area |
| population size | total number of individuals in a population |
| r-strategist | species characterized by rapid growth, high fertility, short lifespan, and exponential population growth |
| stabilizing selection | type of natural selection in which the average form of the trait is favored and becomes more common |
