A Trip Through Geologic Time

Question 1

Paleontologists are scientists who study _________________________.

Accepted Answer

Fossils

Question 2

Generally, only the ________________ parts of organisms become fossils.

Accepted Answer

Hard

Question 3

What led scientists to infer that Earth is about 4.6 billion years old?

Accepted Answer

using radioactive dating on moon rocks

Question 4

Plant leaves may form a fossil called a(n) _________________, a thin layer of carbon on rock.

Accepted Answer

Carbon Film

Question 5

Earth’s earliest atmosphere lacked which gas that is necessary for life to exist today?

Accepted Answer

oxygen

Question 6

Geologists use radioactive dating to

Accepted Answer

determine the absolute ages of rocks.

Question 7

Principle states that the geologic processes that change Earth today are the same as the past?

Accepted Answer

uniformitarianism

Question 8

If layer C is sedimentary rock and layer G is igneous rock, which would contain fossils?

Accepted Answer

C

Question 9

How do layers B and D compare in age?

Accepted Answer

D is older than B

Question 10

Late in the Paleozoic Era, Pangaea formed. The climate in the center of Pangaea was

Accepted Answer

hot, dry desert climate.

Question 11

Scientists know how animals changed over time by studying information contained in the ______.

Accepted Answer

Fossil Record

Question 12

A type of organism that no longer exists on Earth is said to be

Accepted Answer

extinct.

Question 13

The relative age of a rock is

Accepted Answer

its age compared with the ages of other rocks.

Question 14

About 2.5 billion years ago, organisms that could use energy from sunlight released _____

Accepted Answer

Oxygen

Question 15

What is the age of an intrusion in relation to the sedimentary rock layers which it passes?

Accepted Answer

always younger

Question 16

What are fossils?

Accepted Answer

the preserved remains of organisms that lived in the past

Question 17

_______ fossil forms when dissolved minerals replace the remains and then harden to form rock.

Accepted Answer

Petrified

Question 18

A fossil formed when minerals replace all or part of an organism is called a

Accepted Answer

petrified fossil.

Question 19

Around 250 million years ago, all the continents were joined in one landmass, called Cambria

Accepted Answer

False

Question 20

_____ is a gap in the geologic record where some rock layers have been lost because of erosion.

Accepted Answer

unconformity

Question 21

What has the study of fossils allowed scientists to do?

Accepted Answer

describe past environments and the history of life

Question 22

The fossil record show that life on Earth has changed over time. Older rocks contain fossils of

Accepted Answer

simpler organisms.

Question 23

Rock layers are always younger than the faults that cut across them.

Accepted Answer

False

Question 24

__fossils are helpful to geologists because they reveal the relative ages of the rock layers

Accepted Answer

Index

Question 25

The time it takes for half of the radioactive atoms of a radioactive element to decay is the

Accepted Answer

half-life.

Question 26

Radioactive decay occurs when atoms of some elements

Accepted Answer

break down to form atoms of another element.

Question 27

Geologists use the radioactive element ___________to determine the age of an oganism's bone.

Accepted Answer

Carbon-14

Question 28

Footprints and trails are examples of trace fossils

Accepted Answer

True

Question 29

Fossils usually occur in metamorphic rock.

Accepted Answer

False

Question 30

Radioactive dating works best with what type of rocks?

Accepted Answer

igneous rocks

Question 31

The long span of time in Earth’s history and ended 542 millions years ago is called

Accepted Answer

Precambrian Time.

Question 32

The law of superposition helps geologists determine the absolute age of a rock layer.

Accepted Answer

False

A Trip Through Geologic Time

Questions 32

A Trip Through Geologic Time

Questions 32