Fossil Record Flashcards
A principle that states that geologic processes that occurs in the past can be explained by current geologic processes.
Uniformitarianism
A principle that states geologic change occurs suddenly.
Catastrophism
The scientific study of fossils.
Paleontology
Any method of determining whether an event or object is older or younger than other events or objects.
Relative Dating
Any method of measuring the age of an event or object in years.
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 or neutrons (and thus a different atomic mass)
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 of when sediment is not deposited for a long period of time.
Unconformity
An event when species vanish much faster than they are replaced.
Mass Extinction
A warm, wet climate that gave rise to lush vegetation and abundant life. 199.6 million to 145.5 million years ago. long-necked and paddle-finned pleasures, giant marine crocodiles, sharks, and rays were all dominant creatures at the time.
Jurassic period
The period between 145.5 and 65.5 million years ago, the last period of the Mesozoic Era, following the Jurassic and ending with the extinction of the dinosaurs (except birds).
Cretaceous period
An interval of the Paleozoic Era that follows the Silurian Period and precedes the Carboniferous Period, spanning between about 419.2 million and 358.9 million years ago.
Devonian period
The third and last of the three periods of the Cenozoic Era.
Quaternary period
Lasted from 299 to 251 million years ago and was the last period of the Paleozoic Era.
Permian period
