Fossils

Question 1

uniformitarianism

Answer 1

the theory that changes in the earths crust during geological history have resulted in the action of continuous and uniform processes

Question 2

catastrophism

Answer 2

changes in the earth made from sudden and catastrophic events

Question 3

palientoligy

Answer 3

the scientific study of fossils

Question 4

relative dating

Answer 4

any method of determining whether an event or object is older than another

Question 5

superposition

Answer 5

a principle that states that younger rocks are above older rocks

Question 6

geologic coulumn

Answer 6

an arrangement in rock layers in which the oldest are at the bottom

Question 7

uncomformity

Answer 7

a break in geologic records created when rock layers are eroded or when sediment is not deposited for a long time

Question 8

absolute dating

Answer 8

any method of measuring the age of an event in years

Question 9

isotope

Answer 9

an atom that has the same umber of protons a the atoms of the same element

Question 10

radioactive decay

Answer 10

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

Question 11

radiometric dating

Answer 11

a method of determining age using the relative percentages of a radioactive isotope

Question 12

half-life

Answer 12

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

Question 13

fossil

Answer 13

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

Question 14

trace fossil

Answer 14

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

Question 15

mold

Answer 15

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

Question 16

cast

Answer 16

a type of fossil that is formed when sediments fill a cavity left by a decomposed organism

Question 17

index fossil

Answer 17

a fossil that is found in the rock layers of only one geologic age and that is used to estabalish the age of rock layers

Question 18

geologi time scale

Answer 18

the standard method used to divide the earths long natarual history

Question 19

eon

Answer 19

the largest division of geologic time

Question 20

era

Answer 20

two or more periods

Question 21

epoch

Answer 21

a subdivision of geologic time

Question 22

extinction

Answer 22

the death of ever member of species