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Chapter 4 Vocabulary
Vocabulary
Term | Definition |
---|---|
Fossils | Traces and remains of living things from long ago. |
Original Remains | Fossils that are actual bodies or body parts of organisms. |
Ice Core | A tubular sample that shows the layers of snow and ice that have built up over thousands of years |
Relative Age | Age of an event or object in relation to other events or objects. |
Index Fossil | Fossils of organisms that were common, that lived in many areas, and that existed only during specific spans of time. |
Absolute Age | The actual age of an event or object. |
Half-Life | Length of time it takes for half of the atoms in a sample of a radioactive element to change from an unstable form into another form. |
Uniformitarianism | The idea that Earth is an always-changing place, and the same forces of change at work today were at work in the past. |
Geologic Time Scale | Divides Earth's history into intervals of time defined by major events or changes on Earth. |