Fossil Record Vocab Flashcards
A principle that states that geologic processes that occurred in the past can be explained by current geologic processes.
uniformitarianism
A principle that states that geologic changes occur suddenly.
catastrophism
The scientific study of fossils.
paleontology
Any method of determining whether an event or object is older or younger than events or objects.
relative dating
Measure the physical properties of an object itself and use these measurements to calculate its age.
absolute dating
A principle that states that younger rocks lie above older rocks lie above older rocks of the layers have not been disturbed.
superposition
An atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons.
isotope
The process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element.
radioactive decay
The time needed for half of a sample of a radioactive substance to undergo radioactive decay.
half-life
The remains or physical evidence of an organism preserved by geological processes.
fossil
A fossilized mark that is formed in soft sediment by the movement of an animal.
trace fossil
A mark or cavity made in a sedimentary surface by a shell or other body.
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
When species vanish much faster than they are replaced.
mass extinction
