| A | B |
|---|
| stabilizing selection | increase in the number of average individuals in a population |
| directional selection | frequency of a trait moves in one direction |
| normal distribution | forms bell shaped curve |
| polygenic trait | a trait influenced by several genes |
| genetic drift | random change in allele frequency in a population; due to chance |
| nonrandon mating | mating with individuals with similar genetic make up |
| gene flow | movement of alleles into and out of a population |
| Hardy-Weinburg | frequencies of alleles in a population change only when evolutionary forces act on them |
| K-strategists | long life span; few young, extensive parental care |
| R-strategists | short life span; reproduce in large numbers; no parental care for young |
| density independent | population growth limited by environmental factors like climate |
| logistic model | population model; exponential growth is limited by density dependent factors |
| density dependent | resources such as food and water limit population growth |
| carrying capacity | population size that an environment can sustain |
| exponential growth curve | J curve; population increases steadily |
| population model | hypothetical population that exhibits characteristics of a real population |
| dispersion | how individuals in a population are arranged |
| population density | number of individuals that live in a given area |
| population size | number of individuals in a population |
| population | all the individuals of a species that live together in one place |
