| A | B |
|---|
| fossil | remains, imprints, or traces of prehistoric organisms |
| fossil record | a chronologically dated record of many different life forms that existed in the past |
| index fossil | remains of species that existed on Earth for relatively short periods of time, were abundant, and were widespread geographically |
| trace fossil | evidence of the activities of once living organisms such as footprints |
| mineral replacement fossil | fossil made by the tiny spaces of hard parts filling with minerals |
| carbon film fossil | fossil formed when heat and pressure cause an organism's organic material is released as a gas and leaves behind an imprint |
| mold fossil | a hollow impression made after an organism has decayed and dissolved |
| preserved remain fossil | fossil formed from amber, ice or tar trap and preserve the soft parts of an organism |
| relative dating | Using the age of rocks and index fossils to determine the age of a fossil |
| radiometric dating | process used to calcualte the absolute age of rock by using the half-life of isotopes |
| sedimentary | type of rock that fossils form in |
| decomposition | must be prevented in order for fossils to form |
| cast fossil | a replica of an organism formed by mineral-rich water filling in the mold |
