| A | B |
| ecology | the study of the relationship between living organisms and their environment |
| ecologist | someone who studies natural relationships |
| habitat | a place where an organism lives |
| adaptation | inherited characteristics that help an organism survive and reproduce in its environment |
| ecosystem | interaction between living and non-living parts of the environment |
| symbiosis | this occurs when two species live closely together in a relationship that lasts over time |
| mutualism | a relationship where both partners benefit |
| parasitism | a relationship where one partner benefits, the other is harmed |
| commensalism | a relationship where one partner benefits, and the other appears unaffected |
| host | the partner that is harmed in a parasitic relationship |
| parasite | the partner that benefits in a parasitic relationship |