| A | B |
|---|
| biological evolution | change of one kind of organism into another kind |
| acquired characteristics | traits caused by an animal's environment |
| natural selection | only those organisms with the best traits survive and reproduce |
| phylogenetic tree | classification showing the path of evolution |
| common ancestor | common link on the phylogenetic tree |
| missing link | unknown "transitional" organism |
| fossil record | a record of past living things |
| Darwin | formed theory of natural selection |
