| A | B |
|---|
| evolution | change over time |
| fossil | the preserved remains of an ancient organism |
| natural variation | differences among individuals within a species |
| struggle for existence | competition among members of a species |
| fitness | indivindividuals who survive and reproduce in a specific environment |
| adaptation | inherited characteristics that increase an organisms chances of survival |
| natural selection | survival of the fittest |
| common descent | all species come from common ancestor |
| homologous structure | structures that develop from same embryonic tissues, but form different structures |
| vestigial organ | organs with little or no function |
