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the worlds history -
Earth's history. (earth-science)
Question | Answer |
---|---|
Uni-Formitarianism | Today's geologic process (such as weathering process, erosion, volcanoes, earthquakes, etc.) Also took place in the past. |
Relative age | Comparing a rock's age to another rock based on its location in rock layers. |
Absolute Age | The actual age (#)of a fossil |
Original Horizontality | Sediments settle with horizontal layers that are parallel to the ground |
Super-Position | Oldest rock layer is at bottom and each layer above is the youngest. |
Igneous Intrusion | When Magma is forced upward into rocks. |
Precambrian Eon | 85% of earth's history; no fossil record; earth's formation. |
Paleozoic Era | 8.5% of earth's history several plant and animal species evolve. |
Mesozoic Era | 3.5 of earth's history several dinosaurs and birds evolve. |
Cenozoic Era | 1.4% of earth's history mammals (humans) evolve. |
Radioactive decay | Nuclei of atoms break apart of long periods of time. |
Half life | The # of years needed for the half the locations to decay; 50%->25%->12.5%->6.25->3.125% |