| A | B |
|---|
| natural selection | organisms with favorable traits survive and reproduce |
| adaptation | an inherited trait that increases an organism's chance of survival |
| variation | differences between organisms |
| prokaryote | unicellular primitive organism; does not have a nucleus |
| eukaryote | cell with a nucleus & organelles |
| homologous structure | similar features that originated in a shared ancestor; |
| Example of homologous structure | bird wings and human arms |
| analogous structure | have same function but different origin |
| Ex. of analogous structure | bird wings & butterfly wings |
| vestigial structure | features useful to our ancestors but not to us |
| Ex. of vestigial structure | appendix, tailbone |
