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Science slides #1
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Term | Definition |
---|---|
Fossils | The preserved remain of ancient living things |
catastrophism | The idea that conditions and organisms on earth, change in quick, violent events |
uniformitarianism | Geologic processes that occur today are similar to those that have occurred in the past |
carbon film | The fossilized carbon outline of an organism or part of an organism |
mold | The impression in a rock left by an ancient organism |
cast | Fossil copy of an organism made when a mold of the organism is filled with sediment or mineral deposits |
trace fossil | The preserved evidence of the activity of an organism |
paleontologist | Scientist who study fossils |
relative age | The age of rocks and geologic features compared with other rocks and features nearby |
superposition | The principle that in undisturbed rock layers, the oldest rocks are on the bottom |
inclusion | A piece of an older rock that becomes part of a new rock |
unconformity | A surface where rock has eroded away, producing a break, or gap, in the rock record |
correlation | Matching rocks and fossils from separate locations |
index fossils | Species that existed on earth for a short length of time, were abundant, and inhabited many locations |
absolute age | To mean the numerical age, in years, of a rock or object |
isotopes | Atoms of the same element that have different numbers of neutrons |
radioactive decay | The process by which an unstable element naturally changes into another element that is stable |
half-life | the time required for half of the parent isotopes to decay into daughter isotopes |