| Term | Definition |
| natural selection | process that makes change possible in living things |
| adaptive radiation | the change from a common ancestor into a number of different species |
| ecological succession | changes that take place over time in the types of organisms that live in that area |
| primary succession | occurs in an area where no soil exists, such as on bare rock |
| pioneer species | term scientists use to describe first organisms to survive and reproduce in an area |
| climax community | mature community |
| secondary succession | occurs as a result of a disturbance to an area that already has soil and was once the home of living organisms |