| A | B |
|---|
| geology | the study of earth |
| geologic time scale | outline of the earth's history |
| era | the largest division of geologic time |
| theory | an educated guess on how somthing in the past happened |
| Law | a rule rule that can't be broken |
| Fossils | A track, trace, or the remains of an organism preserved in rock |
| Index Fossils | Species that are wide spread & short lived |
| trilobite | an index fossil from the paleozoic era |
| ammonite | index fossil from the mesozoic era |
| extinct | a polulation that has no living memeber |
| relative dating | the process of determing whether or not one event happened before or after another |
| radiometric dating | A technique using the half lives of elements such as uranium or carbon to date rocks |
| half -live | about the time needed for one half of a sample of radioactive atoms to decay id called this |
