| A | B |
|---|
| period | time span shorter than an era |
| index fossil | fossil used to compare relative ages of other fossils |
| endosymbiosis | theory that proposes that eukaryotic cells formed from prokaryotic communities of cells |
| geologic time scale | measurement of evolutionary time |
| era | span of geologic time that is subdivided into periods |
| fossil record | provides evidence about history of life on Earth |
| mass extinction | disappearance of many species at the same time |
| proteinoid microspheres | tiny bubbles formed by large organic molecules |
| paleontologist | scientist who studies fossils |
| extinct | species that no longer exists |
| relative dating | compare fossils to determine age |
| coevolution | two species evolve in response to changes in each other |
| macroevolution | large scale evolutionary changes that take place over long periods of time |
| convergent evolution | unrelated organisms come to resemble each other |
| adaptive radiation | species evolves into many different species |
| punctuated equilibrium | long stable periods punctuated by brief rapid changes |
| half life | length of time required for half of radioactive isotopes to decay |
