| A | B |
|---|
| ecology | scientific study of interactions between organisms & their envir. |
| biosphere | portion of Earth that supports life; high in atmosphere to bottom of oceans. |
| abiotic factor | nonliving parts of an organism's environment; air currents, temperatures, moisture, light, and soil. |
| population | group of organisms all of the same species, which interbreed & live in same place at the same time. |
| biological community | community made up of interacting populations in a certain area at a certain time. |
| ecosystem | interactions among populations in a community; the communities. physical surroundings, or abiotic factors. |
| habitat | place where an organism lives out its life. |
| niche | role/position species has in its environment; includes all biotic & abiotic interactions as an animal meets its needs for survival & reproduction. |
| symbiosis | permanent, close assoc. between 2 or more organisms of different species. |
| commensalism | symbiotic relationship in which 1 species benefits & the other species is neither harmed nor benefited. |
| mutualism | a symbiotic relationship in which both species benefit. |
| parasitism | symbiotic relationship where 1 organism benefits at the expense of another, usually another species. |
| autotroph | organisms that use energy from the sun or enegry stored in chemical compounds to manufacture their own nutrients. |
| heterotroph | organisms that cannot make their own food and must feed on other organisms for energy and nutrients. |
| decomposer | organisms, such as fungi & bacteria, that break down & absorb nutrients from dead orgamisms. |
| food chain | simple model that shows how matter & energy move through an ecosystem. |
| trophic level | organism that represents a feeding step in the movement of energy & materials through an ecosystem. |
| food web | model that shows all the possible feeding relationships at each trophic level in a community. |
| biomass | the total mass or weight of all living matter in a given area. |
