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Changing Earth
Term | Definition |
---|---|
Mold Fossils | A fossil formed when an animal, plant, or other organism dies and is covered by sediment. |
Cast Fossils | A cast fossil preserves the impression of the hard parts of an organism |
Carbon Film fossil | an organism outline of a fossil |
Trace Fossil | a fossil of a footprint, trail, burrow, or other trace of an animal |
Preserved Remains | remains of a prehistoric creature preserved in something like a rock,amber or ice |
Catastrophism | idea that conditions and organisms on Earth change in quick , violent events |
Uniformitarianism | states that geologic processes that occur today are similar to those that have occurred in the past |
stratigraphy | the branch of geology that studies the order and relative age of rock/soil layers on Earth. |
law of superposition | states that the youngest layers of Earth are located on the surface and as you go deeper into the Earth, the layers get older. |
relative age | is a way of describing how old something is not by using numbers but by using a comparison. |
index fossil | fossil of an organism that was alive for only a short period of time, were abundant and widespread geographically; scientists can use these to assign dates to rock layers |
absolute age | the numerical age in years of an object |
radiometric dating | process to determine absolute age of an object isotopes break down into other isotopes and particles |
halflife | time it takes for half the atoms of an isotope to decay |