fossil records

Question 1

uniformitarianism

Answer 1

pricinple that states that geologic processes that occurred in the past can be explained by current geologic process

Question 2

catastropism

Answer 2

principle that states that geologic change occurs suddenly

Question 3

paleontology

Answer 3

scientific study of fossils

Question 4

relative dating

Answer 4

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

Question 5

absolute dating

Answer 5

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

Question 6

superposition

Answer 6

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

Question 7

unconformity

Answer 7

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

Question 8

isotope

Answer 8

an atom that has the same number of protons (or the same atomic number) as other atoms of the same elements do but that has a different number of netruouns (and thus a different atomic mass)

Question 9

radioactive decay

Answer 9

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

Question 10

half-life

Answer 10

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

Question 11

fossils

Answer 11

remains of physical evidence of an organism preserved by geologic process

Question 12

trace fossils

Answer 12

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

Question 13

mold

Answer 13

mark or cavity made in a shell or other body q

Question 14

cast

Answer 14

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

Question 15

mass extinction

Answer 15

death of every member of a species

Question 16

Jurassic period

Answer 16

201.3 million years ago dinosaurs and flying pterosaurs

Question 17

Cretaceous period

Answer 17

145.5 million years ago Dinosaurs were the dominant group of land animals, especially “duck-billed” dinosaurs (hadrosaurs), such as Shantungosaurus, and horned forms, such as Triceratops.

Question 18

Devonian period

Answer 18

419.2 million years ago agnathans (jawless fish) and placoderms (the first jawed fish)

Question 19

Quaternary period

Answer 19

2.6 million years ago mammals, flowering plants, and insects dominated the land.

Question 20

Permian period

Answer 20

47 million years pelycosaurs, both herbivores and carnivores.