Transcript Chapter 9 Study Notes

Chapter 9 Study Notes
A View of Earth’s Past
1

Scientists created the first _________
__________ by determining the relative ages
of sedimentary rock in areas all over the world.


geologic
column
2

If the Cretaceous Period began about ______,
this means it began __________ years ago.


146-Ma
146-million
3

Geologic time is divided into ____________.

four eons
4

A geologic _________ is usually named for
the place where its characteristic ______ were
first discovered.


period
fossils
5

The ________ development of new organisms
from preexisting organisms is called _______.


gradual
evolution.
6

The division of geologic time that makes up
about ____ % of Earth’s history is called
_____________ time.


88%
Precambrian
7

Scattered landmasses on Earth merged into a
_______ _______ during the Paleozoic Era.

super continent
8

According to the ______ hypothesis, dinosaurs
became extinct when a giant meteorite crashed
into Earth.

impact
9

The __________ Era is known as the Age of
________ .


Cenozoic
Mammals
10

The ________ Epoch began about 5.3 Ma, or
5.3 _______ ______ ago.


Pliocene
million years
11

The most common Pliocene _________ _____
are ________.


Pliocene
stromatolites
12

New mammal species developed when
temperatures ______ during the ice ages of the
Cenozoic Era.

decreased
13

On a geologic column, the ______ _____ are
on the _______.


oldest rocks
bottom
14

Scientists have most accurately determined the
_______ ages of rock layers by using
radiometric dating methods.

absolute
15

Nearly half the Earth’s valuable mineral
deposits are found in rocks from __________
time.

Precambrian
16

Rock _______ that match a similar layer in a
geologic column may have formed at the
______ time.


layers
same
17

_________ became _______ at the end of the
_________ era.



Dinosaurs
extinct
Mesozoic
18

_________ became the dominant animals
during the ________ era.


Mammals
Cenozoic
19

The geologic _____ ______ is a table that
outlines the development of _______.


time scale
Earth
20

A _______ is a unit of geologic time into
which an era is divided.

period
21

The geologic column is an ordered
arrangement of rock layers ______ on their
____.


based
ages
22

A large area of ______ Precambrian _____ is
called a _______.



exposed
rocks
shield
23

_______ fossils can be used to _____ rocks.


Index
date
The End!!!