Fossil record Flashcards
uniformitarianism
a principle that states that geological processes that occur in the past
catastrophism
a principle that states that geologic change occurs suddenly
paleontology
scientific study of fossils
relative dating
determining whether an event or object is older or younger
absolute dating
measure the physical properties of an object itself and use these measurements to calculate its age.
superposition
a principle that states that younger rocks lie above older rocks
isotope
an atom that has the same number of protons same number as other atoms
radioactive decay
the process in which a radioactive isotope tends to break down
half-life
the time needed for half of a sample of a radioactive substance
fossil
the remains or physical evidence of an organism
trace fossil
a fossilized mark that is formed in soft sediment by movement of an animal
mold
a mark or cavity made in sedimentary surface by a shell or other body
cast
a type of fossil that forms when sediment fill in the cavity left by decomposed organism
unconformity
a break in the geologic record created when rock layers are eroded
mass extinction
the death of every member of a species
