| A | B |
|---|
| Fossils | Remains, imprints, or traces of once-living organisms. |
| Absolute Dating | Method using properties of atoms in rocks and other objects to determine their ages. |
| Extinct | When there are no longer any living members of a species. |
| Radiometric | Method of dating rocks when the amounts of parent and daughter materials are measured. |
| Uniformitarianism | Principle stating that Earth's processes occuring today are similar to those that occurred in the past. |
| Carbon | Element found in tissues of most organisms. |
| Unconformities | Gaps found in rock records. |
| Relative Dating | Method used to determine the order of events and relative ages of rocks by examining the position of rocks in a sequence. |
| Radioactive | Kind of decay or change in which a new element eventually forms. |
| Half-life | Time it takes for half of the atoms in a radioactive element to decay. |
| Geology | Branch of science that includes the study of rocks and fossils. |
| Original Remains | Actual organism or parts of organism protected from decay. |
