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Question 1

Principles for Determining Relative Age

Answer 1

Original horizontality, and Superposition

Question 2

Original horizontality-

Answer 2

Sedimentary rocks are deposited in horizontal or nearly horizontal layers.

Question 3

Superposition-

Answer 3

In an undisturbed rock sequence, the oldest rocks are at the bottom and
each consecutive layer is younger than the layer beneath it.

Question 4

Two ways to determine age:

Answer 4

Relative age dating, and absolute age dating.

Question 5

The Geologic Time Scale

Answer 5

eon, era, period, epoch.

Question 6

What epoch do we live in?

Answer 6

We live in the Holocene epoch.

Question 7

what are eons, eras, periods, and epochs measured in?

Answer 7

eons: billions eras: tens of millions periods: millions Epochs: hundreds of thosands

Question 8

Absolute-Age Dating

Answer 8

A method for determining the actual age of a rock or fossil using the decay rate of radioactive isotopes.

Question 9

Radioactive decay-

Answer 9

The emission of radioactive particles and the resulting change into other isotopes over time

Question 10

Types of Fossils

Answer 10

Index fossils, Original preservation, mineral preservation, mold, cast, trace.

Question 11

Earth’s Early Heat Sources:

Answer 11

–Gravitational contraction
–Radioactivity from core.
–Bombardment by meteorites, comets.

Question 12

Precambrian Earth
what is the oldest known mineral?

Answer 12

Oldest: zircon 4.2 billion years old

Question 13

Metamorphic rocks that have been dated to 4.28 by.

Answer 13

Amphibolites

Question 14

What is the Earliest known life form on Earth? What did it Produced? How old?

Answer 14

Cyanobacteria, Produced oxygen, 3.4 billion years old.

Question 15

Prokaryote

Answer 15

Single-celled organism lacking a nucleus.

Question 16

Stromatolites

Answer 16

Fossilized evidence of cyanobacteria.

Question 17

eukaryote

Answer 17

An organism composed of cells that contain a nucleus. 2.1 billion years old

Question 18

Ediacara

Answer 18

Complex multi-celled organisms provide the first evidence of advanced life-forms on Earth. (~600 million years ago.)

Question 19

DNA

Answer 19

More than 4 billions years ago, nessasary precursor to life..

Question 20

Paleozoic Era

Answer 20

Marine life becomes abundant, diverse, and spreads to land.

Question 21

Mesozoic Era-

Answer 21

Climates become tropical, Large reptiles dominate land, sea, and air. Large meteorite impact causes mass extinction.

Question 22

Cenozoic Era

Answer 22

Climates become cool, mammals become the dominant life-form.
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Question 23

Precambrian-

Answer 23

All of geologic time prior to ~600 million years ago.

Question 24

what comprises the modern eon

Answer 24

The Paleozoic, Mesozoic and Cenozoic eras

Question 25

what periods comprise the Paleozoic era.

Answer 25

The Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian