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 changes 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 or objects

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 into 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 of 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 a cavity left by a decomposed organism

Question 14

mass extinction

Answer 14

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

Question 15

Jurassic period

Answer 15

a geologic period and stratigraphic system that spanned from the end of the Triassic Period 201.3 million years ago to the beginning of the Cretaceous Period

Question 16

Cretaceous period

Answer 16

a geological period that lasted from about 145 to 66 million years ago

Question 17

Devonian period

Answer 17

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 18

Quaternary period

Answer 18

the current and most recent of the three periods

Question 19

Permian period

Answer 19

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

Question 20

uncomformity

Answer 20

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