Fossil Record Vocab

Question 1

uniformitarianism

Answer 1

a principle that states that geological processes that occurred in the past can be explained by current geologic processes

Question 2

catastrophism

Answer 2

a principle that states that geologic change occurs suddenly

Question 3

paleontology

Answer 3

the scientific study of fossils

Question 4

relative dating

Answer 4

any method of determining whether an event or object is older or younger than the other

Question 5

absolute dating

Answer 5

any method of measuring the age of an event or object in years

Question 6

superposition

Answer 6

a principle that states that younger rocks lie above older rocks if the layers have not been distributed

Question 7

isotope

Answer 7

an atom that has the same number of protons as other atoms of the same element do, but has different nutrons

Question 8

radioactive decay

Answer 8

the process in which a radioactive isotope tends to break down into a stable isotope of the same or other element

Question 9

half-life

Answer 9

the time needed for half of a sample of a radioactive substance to undergo radioactive decay

Question 10

fossil

Answer 10

the remains or physical evidence of an organism preserved by geological processes

Question 11

trace fossil

Answer 11

a fossilized mark that is formed in soft sediment by the movement of an animal

Question 12

mold

Answer 12

a mark or cavity made in a sedimentary surface by a shell or other body

Question 13

cast

Answer 13

a type of fossil that forms when sediments fill in the cavity left by a decomposed organism

Question 14

unconformity

Answer 14

a break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time

Question 15

mass extinction

Answer 15

an event that occurs at the end of a geologic period when most of living organisms go extinct

Question 16

Jurassic period

Answer 16

a period of time that was 199.6 million to 145.5 million years ago that was characterized by a warm, wet climate that gave rise to lush vegetation and abundant life

Question 17

Cretaceous period

Answer 17

the period between 145.5 and 65.5 million years ago

Question 18

Devonian period

Answer 18

a geologic period and system of the Paleozoic, spanning 60.3 million years from the end of the Silurian, 419.2 million years ago

Question 19

Quaternary period

Answer 19

the current and most recent of the three periods of the Cenozoic Era which we are still in

Question 20

Permian period

Answer 20

a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago