| A | B |
|---|
| natural selection | process by which organisms that are best suited to their environment survive and pass their successful traits on to their offspring |
| adaptation | a trait that helps an organism to survive in its environment |
| niche | job description for an organism |
| competition | struggle for food, space, other resources |
| predation | relationship in which one species feeds upon another |
| predator | an organism that hunts and kills another for food |
| prey | an organism hunted for food |
| symbiosis | a close relationship between two species in which at least one benefits |
| mutualism | a kind of symbiosis in which BOTH species benefit |
| commensalism | a kind of symbiosis in which one organism benefits, the other is not harmed |
| parasitism | a kind of symbiosis in which one organism benefits, the other is harmed |
| parasite | an organism that lives in or on another, obtaining food and causing harm to the host |
| host | the organism that a parasite lives in or on |
