| A | B |
|---|
| population density | number of individuals of a particular species per unit area or volume |
| exponential growth | growth of a population that multiplies by a constant factor at constant time intervals |
| limiting factor | condition that restricts a population's growth, such as space, disease and food availability |
| carrying capacity | number of organisms in a population that an environment can maintain |
| density-dependent factor | factor that limits a population more as population density increases |
| density-independent factor | factor unrelated to population density that limity a population |
| age structure | proportion of people in different age groups in a population |
| interspecific competition | competition between species that depend on the same limited resource |
| competitive exclusion | one species succeeding over another when the growth of both species is limited by the same resource |
| niche | unique living arrangement of an organism defined by its habitat, food sources, time of day it is most active, and other factors |
| predation | interaction in which one organism consumes another |
| symbiotic relationship | close interaction between species in which one species lives in or on the other |
| parasitism | relationship in which a parasitic organism obtains its food at the expense of a host organism |
| mutualism | type of symbiotic relationship in which both organisms involved benefit |
| commensalism | symbiotic relationship in which one organisms benefits, while the other organism is neither harmed nor helped |
| ecological succession | series of changes in the species in a community, often following a disturbance |
| primary succession | process by which a community arises in a virtually lifeless area with no soil |
| secondary succession | change following a disturbance that damages an existing community but leaves the soil intact |
| introduced species | species moved by humans to new geographic areas, either intentionally or accidentally |
