| Term | Definition |
|---|
| population | allthe individuals of a species that live together in one place at one time |
| population size | # of individuals in a population |
| population density | the # of individuals that live in a given area |
| dispersion | how individuals of a population are arranged in a given area |
| 3 types of dispersion | randomly spaced ( self determined or determined by chance), evenly spaced (located on regular intervals), clumped(individuals are bunched together in clusters) |
| population model | a hypothetical population that attempts to exhibit the key characteristics of a real population |
| exponential growth curve | a curve in which the rate of population growth stays the same , as a result the population size increases steadily |
| carrying capacity | the population size that an environment can sustain |
| logistic model | population model in which expnential growth is limited by a density dependent factor |
| r strategists | species that grow when the environmental conditions allow them to reproduce ( bacteria, cockroaches, mosiquitos are found in rapidly changing environments) |
| k strategists | organisms that grow slowly because their population density is near the carrying capacity- they usually have long lifespans & few young. example- whale |
| hardy Weinberg principal | the frequency of alleles in th epopulatin do not change unless evolutionary forces act on the population |
| gene flow | the movement of alleles into or out of a population, this can be caused by migration |
| migration | the movement of indivduals to or from a population |
| nonrandom mating | sometimes individuals prefer to mate with others that live nearby or are of their own phenotype (ex inbreeding) |
| genetic drift | changes in the gene pool of a small population due to chance. Tends to reduce genetic variation. |
| polygenic trait | characteristic of an organism that influenced by several genes |
| normal distribution | a bell shaped pattern of scores that froms the normal curve |
| directional selection | __________ ________ is most common when a population's environment changes or when members of a population migrate to a new habitat with different environmental conditions from their former one,-example- shift in allele frequency in a consistent direction (light colored moths to dark colored moths due to camouflage) |
| stabilizing selection | Organisms with extreme traits are eliminated (favors common traits) Ex) human babies that are abnormally small or large have low survival rate. This causes the distribution to become narrow and increase the proportion of extreme types |
Combine with other sets
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