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11 Cards in this Set
- Front
- Back
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petrified fossil |
minerals replace the remains changing them into rock fossils. |
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mold |
a hollow space in sediment in the shape of an organism. |
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cast |
a copy of the shape of the organism. |
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relative dating |
Used to determine which 2 fossils is older. |
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radioactive dating |
allows to determine actual age of fossils. |
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radioactive element |
unstable elements that decay or break down into different elements. |
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half life |
time it takes a radioactive element for the half of the atoms in a simple state to decay. |
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fossil record |
millions of fossils scientists have collected. |
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extinct |
no members of species are alive. |
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gradualism |
proposes that evolution occurs slowly but steadily (tiny changes in a species gradually add up to major changes over time.) |
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punctuated equilibria |
accounts for gaps in the fossil record (according to this theory species evolve quickly during relatively short periods. |
