Fossil Record Flashcards
uniformitarianism
a principle that states that geologic processes that occurred in the past can be explained by current geologic processes.
catastrophism
a principle that states that geologic change occurs suddenly.
paleontology
the scientific study of fossils
relative dating
any method of determining whether an event or object is older or younger than other events or objects.
absolute dating
determine how much time has passed since rocks formed by measuring the radioactive decay of isotopes or the effects of radiation on the crystal structure of minerals.
superposition
a principle that states that younger rocks lie above older rocks if the layers have not been disturbed.
isotope
A fossil can be used to determine the age of the strata in which it is found and to help correlate between rock units.
radioactive decay
occasionally the unstable isotope will change its number of protons, neutrons, or both.
half-life
the time taken for the radioactivity of a specified isotope to fall to half its original value.
fossil
the preserved remains of plants and animals whose bodies were buried in sediments, such as sand and mud, under ancient seas, lakes, and rivers.
trace fossil
a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself.
mold
a hollow container used to give shape to molten or hot liquid material when it cools and hardens.
cast
measures what students know and can do using California.
unconformity
a break in time in an otherwise continuous rock record.
mass extinction
when species vanish much faster than they are replaced.
