| A | B |
|---|
| homologous structures | similar structures in different species |
| vestigial organs | organ without any obvious function ex. appendix |
| branching tree | diagram that shows how scientists think different groups of organisms are related. |
| common ancestor | oh yes |
| fossil record | the record of preserved evidence of a single species |
| relative dating | a method of determining the age of a fossil by its position in layers of rock |
| absolute dating | the process of determining an age on a specified time scale |
| Geologic Time Scale | period of time covering the physical formation and development of Earth |
| era | long period of time on the Geologic Time Scale |
