| A | B |
|---|
| population | a group of one species that lives in a particular area |
| population density | measurement of how crowded a population is |
| dispersion | distribution of individuals in an area |
| birth rate | number of individuals born in a population |
| death rate | mortality rate |
| age structure | distribution of individuals over different ages in a population |
| growth rate | amount by which a population's size changes |
| immigration | movement of individuals into a population |
| emigration | movement of individuals out of a population |
| exponential model | pattern of growth showing steady growth |
| logistic model | pattern of growth showing limits to population growth |
| limiting factor | something that restrains the growth of a population |
| carrying capacity | the number of individuals an ecosystem can support over a long period of time |
| density-independent factors | a variable that affects a population regardless of the number of individuals in the area |
| density-dependent factors | a variable whose effects on the size or growth of population vary with the number of individuals in the area |
| predation | relationship in which one species feeds on another species |
| interspecific competition | interaction where two or more species use the same limited resource |
| symbiosis | a close, long-term relationship between two organisms |
| parasitism | relationship in which one individual benefits and the other is harmed |
| mutualism | relationship in which both organisms benefit |
| commensalism | relationship in which one organism benefits and the other is not affected |
| ecological succession | the gradual, sequential regrowth of an area |
| primary succession | changes in an area that previously supported no life, (no soil is left) |
| secondary succession | sequential replacement of species after a disruption, soil remains |
| pioneer species | organisms that first colonize an uninhabited area after devastation |
| climax community | a group of organisms that has reached a generally stable state after succession |
