Fossil Record

Question 1

uniformitarianism

Answer 1

a principle that states that geologic 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 other events

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 disturbed

Question 7

isotope

Answer 7

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)

Question 8

radioactive decay

Answer 8

the process in which a radioactive isotope tends to break down onto a stable isotope of the same element or another 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 captivity 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 occurs suddenly

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

the extinction of a large number of species within a relatively short period of time

Question 16

Jurassic period

Answer 16

a time period that lasted 56 million years and was in the middle of the Mesozoic Era

Question 17

Cretaceous period

Answer 17

a time period that lasted almost 80 million years and was the third and final period in the Mesozoic Era

Question 18

Devonian period

Answer 18

a time period that lasted 60 million years and was in the Paleozoic Era

Question 19

Quaternary period

Answer 19

the current and most recent time period of the Cenozoic Era

Question 20

Permian period

Answer 20

a time period that lasted 47 million years and was the final period in the Paleozoic Era