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Fossils / Geologic
Ch. 4 from Changing Earth textbook
Question | Answer |
---|---|
absolute age | specific age of rock or fossil; example |
extinct | gone forever; examples |
extrusion | volcanic lava layer on surface |
half-life | time for half # of radioactive atoms to change (decay) into different type of atoms |
intrusion | magma squeezed up from below; younger than layers it cuts through |
invertebrates | animals without backbone; earliest animals; examples |
law of superposition | |
mass extinction | |
petrified fossil | living thing dies and body / parts slowly replaced by minerals; example |
radioactive decay | one element changes over time to another element; gives off energy; used to figure out how old rocks/fossils are |
relative age | |
trace fossil | evidence left by living thing long ago; examples: tracks, tunnels, turds, nests, etc. |
trilobite | |
uniformitarianism | geology that happened in past, happens now, and will in future too; constant change in Earth; James Hutton idea |
sedimentary | fossils usually found in this type of rock |
4.6 billion years old | |
birds | Robert Bakker and other paleontologist think dinosaurs evolved into this |
unconformity | layer eroded away, then new layers formed above |