| Term | Definition |
| habitat | the area where an organism lives |
| ecological niche | how a species lives |
| competitive exclusion | when 2 species compete for the same resources |
| ecological equivalents | species that occupy similar nices but live in different geographical regions |
| competition | when 2 organisms fight for the same resouces |
| predation | process by which one organism captures and feeds upon another |
| symbiosis | a close ecological relationship between 2 or more organisms of different species that live in direct contact with one another |
| mutualism | where both organisms benefit from one another |
| commensalism | where one organism benefits and the other neither beneifts nor is harmed |
| parasitism | where one organism benefits and the another is harmed |