| A | B |
|---|
| habitat | a place in an ecosystem where a population lives |
| population | all the individuals of the same kind living in the same environment. |
| individual | a single organism in an environment |
| niche | the role each population has in its habitat |
| community | all the populations of organisms living together in an environment |
| ecosystem | a community and its physical environment together |
| producer | an organism that makes its own food (plants) |
| consumer | an organism in a community that must eat to get the energy it needs |
| food chain | the ways in which the organisms of an ecosystem interact with one another according to what they eat |
| decomposer | consumer that breaks down the tissues of dead organisms |
| food web | shows the interactions among many different food chains in a single ecosystem |
| energy pyramid | shows the amount of energy available to pass from one level of a food chain to the next |
| competition | a contest among organisms for the limited resources of an ecosystem |
| symbiosis | a long-term relationship between different kinds of organisms |
| instinct | a behavior that an organism inherits |
| learned behaviors | behaviors animals have learnd from their parents, not inherited from them |
| exotic | an imported of nonnative organism |
| extinct | no longer in existence; describes a species when the last individual of a population dies and that orgqanism is gone forever |
| endangered | a term describing a population of organisms that is likely to become extinct if steps are not taken to save it |
| threatened | describes a population of organisms that are likely to become endangered if they are not protected |
