Fossil Record Flashcards
A principle that geologic processes that occurred in the past can be explained by current geologic processes
uniformitarianism
A principle that states that geologic change occurs suddenly
catastrophism
The scientific study of fossils
paleontology
A method of determining whether an event or object, such as a fossil, is older or younger than other events or objects without referring to the object’s age in years
relative dating
Any method that measures the age of an object or event in years rather than measuring the age relative to another object or event; one such method is radiometric dating
absolute dating
A principle that states that younger rocks lie above older rocks if the layers have not been disturbed
superposition
An atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass)
isotope
The disintegration of an unstable atomic nucleus into one or more different nuclides, accompanied by the emission of radiation, the nuclear capture or ejection of electrons, or fission
radioactive decay
The time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope
half-life
The trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock
fossil
A fossilized mark that formed in sedimentary rock by the movement of an animal on or within soft sediment
trace fossil
In biology, a fungus that looks like wool or cotton
mold
A type of fossil that forms when sediments fill in the cavity left by a decomposed organism
cast
A break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time
unconformity
An episode during which large numbers of species become extinct
mass extinction