Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
The Changing
Surface of Earth
Consultant
Douglas Fisher, Ph.D.
About the Consultant
Copyright © by the McGraw-Hill Companies, Inc. All rights reserved. Permission is granted to reproduce the material
contained herein on the condition that such material be reproduced only for classroom use; be provided to students,
teachers, and families without charge; and be used solely in conjunction with Earth Science. Any other reproduction,
for use or sale, is prohibited without prior written permission of the publisher.
Send all inquiries to:
Glencoe/McGraw-Hill
8787 Orion Place
Columbus, Ohio 43240-4027
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Douglas Fisher, Ph.D., is a Professor in the Department of Teacher
Education at San Diego State University. He is the recipient of an
International Reading Association Celebrate Literacy Award as well
as a Christa McAuliffe award for Excellence in Teacher Education. He
has published numerous articles on reading and literacy, differentiated
instruction, and curriculum design as well as books, such as Improving
Adolescent Literacy: Strategies at Work and Responsive Curriculum Design
in Secondary Schools: Meeting the Diverse Needs of Students. He has taught
a variety of courses in SDSU’s teacher-credentialing program as well as
graduate-level courses on English language development and literacy.
He also has taught classes in English, writing, and literacy development
to secondary school students.
To the Teacher ............................................. v
Note-Taking Tips ...................................... vii
Using Your Science Notebook ............. viii
Chapter 1 Views of Earth
Chapter Preview ....................................... 1
1-1............................................................... 2
1-2............................................................... 5
1-3............................................................... 8
Wrap-Up .................................................. 12
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Chapter 2 Weathering and Soil
Chapter Preview ...................................... 13
2-1.............................................................. 14
2-2.............................................................. 17
2-3.............................................................. 20
Wrap-Up .................................................. 24
Chapter 3 Erosional Forces
Chapter Preview ...................................... 25
3-1.............................................................. 26
3-2.............................................................. 29
3-3.............................................................. 32
Wrap-Up .................................................. 36
Chapter 4 Water Erosion
and Deposition
Chapter Preview ...................................... 37
4-1.............................................................. 38
4-2.............................................................. 41
4-3.............................................................. 44
Wrap-Up .................................................. 48
Chapter 5 Clues to Earth’s Past
Chapter Preview .....................................
5-1 ............................................................
5-2 ............................................................
5-3 ............................................................
Wrap-Up .................................................
49
50
53
56
60
Chapter 6 Geologic Time
Chapter Preview .....................................
6-1 ............................................................
6-2 ............................................................
6-3 ............................................................
Wrap-Up .................................................
61
62
65
68
72
The Changing Su rface of Earth
iii
Note-Taking Tips
Your notes are a reminder of what you learned in class. Taking good
notes can help you succeed in science. These tips will help you take
better notes.
• Be an active listener. Listen for important concepts. Pay attention
to words, examples, and/or diagrams your teacher emphasizes.
• Write your notes as clearly and concisely as possible. The following
symbols and abbreviations may be helpful in your note-taking.
Word or
Phrase
Symbol or
Abbreviation
Word or
Phrase
Symbol or
Abbreviation
for example
e.g.
and
+
such as
i.e.
approximately
with
w/
therefore
without
w/o
versus
vs
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
• Use a symbol such as a star (★) or an asterisk (*) to emphasis
important concepts. Place a question mark (?) next to anything that
you do not understand.
• Ask questions and participate in class discussion.
• Draw and label pictures or diagrams to help clarify a concept.
Note-Taking Don’ts
• Don’t write every word. Concentrate on the main ideas and concepts.
• Don’t use someone else’s notes—they may not make sense.
• Don’t doodle. It distracts you from listening actively.
• Don’t lose focus or you will become lost in your note-taking.
The Changing Su rface of Earth v
Using Your Science Notebook
Name
This note-taking guide is designed to
help you succeed in learning science
content. Each chapter includes:
Date
The Nature of Science
Before You Read
Before you read the chapter, respond to these statements.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
Before You
Read
Language-Based Activities
Activities cover the content
in your science book including
vocabulary, writing, note-taking,
and problem solving.
The Nature of Science
• An important part of science is testing, or
experimenting.
• Technology is useful only in the situation for
which it was designed.
• People began studying weather in the 1800s.
• Science can answer all of the questions that
can be asked.
Science Journal
How do you think scientists could learn more about a clump of stone that could be
a small dinosaur heart?
Anticipation Guide/KWL Charts
Think about what you already know
before beginning a lesson and
identify what you would like
accompany: to go together with; to happen
to learn from reading. at the same time as
Student responses will vary. Accept responses that discuss some reasonable
experiment.
accumulate: to gather, pile up, or collect
accurate: careful and exact; without
mistakes or errors
affect: to influence
Science Journal
Write about what
you know.
approach: to come near
The Nature of Science
1
area: particular space, region, or section
chemical: any substance used in or
obtained by a chemical process
Name
collapse: to fall or shrink together abruptly
and completely
Date
Section 2 Scientific Enterprise
compensate: to make up for
(continued)
Limits of Science
I found this information
on page
.
SE, p. 20
RE, p. 10
Complete the following paragraph by filling in the missing terms
from the word bank.
• scientific methods
• tested
• good
• limited
• observed
• bad
• ethics
• explain
limited
Science is
by what it can
explain
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
component: part of a machine or system
consist: to be made up of; to contain
constant: not changing; remaining the
same; remaining free of variation; regular;
stable
contract: to make or become shorter
or smaller
.
For a question or problem to be studied through scientific methods ,
observed
there must be variables that can be
and
tested
. Questions that deal with
, measured,
ethics
or belief systems cannot be answered by science. Ethics is a system
good
bad
or
.
Writing Activitiesof understanding what is
Doing Science
Contrast ethical behavior in science with scientific fraud. Create
that lists three specific behaviors that are examples of each
Right
These activities help
youa table
think
type of behavior.
I found this information
page
.
about whaton you’re
learning
Ethical Behavior
Scientific Fraud
and make connections to
your life.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Accept all reasonable responses.
SE, pp. 20–22
RE, pp. 10–12
being objective
making up measurements
making conclusions on the
basis of tests and
measurements
changing results
convert: to change from one form to
another form
emerge: to come out; to appear
enormous: having great size
environment: the physical, chemical, and
biotic factors that surround living things
erode: to wear away
eventual: ultimately resulting
exceed: to go beyond or be greater than
expose: to leave open or without
protection; to reveal
extract: to take, get, or pull out
formula: a group of symbols and figures
showing the elements in a chemical
compound
goal: objective or end that one strives
to achieve
hypothesis: a reasonable guess that can
be tested and is based on what is known
and what is observed
impact: a strong effect
indicate: to be or give a sign of
infer: to arrive at a conclusion or an
opinion by reasoning
interval: space or time between events
core: center; a central part of something
layer: one thickness over another
create: to bring about
likewise: in the same way
cycle: series of actions that repeat
locate: to find the position or site of
derive: to get or receive from a source
maintain: to continue; to support
detect: to discover something hidden or
not easily noticed
normal: conforming to a type; standard
or regular pattern
diverse: not all the same, varied
nuclear: of or relating to the atomic nucleus
Earth Science
Vocabulary Development
Vocabulary words help you to better
S YNTHESIZE I T Describe how fraud in scientific research couldunderstand
your science lessons. Learning
affect other
scientists who research in ethical ways.
the Academic Glossary can help you score
higher on standardized tests.
sharing results
taking credit for others’
work
Accept all reasonable responses.
Fraud could mislead other scientists. It could cause them to base their own experiments
on inaccurate information.
The Nature of Science
vi
controversy: argument or debate
Academic Vocabulary
The Changing Su rface of Earth
7
297
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Construct the Foldable as directed at the beginning of this chapter.
Name
Date
Section 1 Science All Around
Mysteries and
Problems
I found this information
on page
.
SE, pp. 6–7
RE, pp. 1–2
(continued)
Chapter Wrap-Up
This brings the information together
for you. Revisiting what you thought
at the beginning of the chapter provides
another opportunity for you to discuss
what you have learned.
Summarize why it was important for scientists to solve the mystery
of the tsunami that struck Japan, on January 27, 1700.
By solving the mystery, scientists discovered that very large
earthquakes can happen in the Pacific Northwest. Knowing that
earthquakes of that size are possible in that area can help people
prepare for the possibility of another similarly large earthquake.
Scientific
Methods
Sequence the scientific methods used to solve a scientific problem
by completing the graphic organizer below.
I found this information
on page
.
SE, p. 8
RE, p. 3
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Gather information.
Note-Taking Based on
the Cornell Two-Column Format
Practice effective note-taking through
the use of graphic organizers, outlines,
and written summaries.
Test the hypothesis.
Science
I found this information
on page
.
SE, p. 9
RE, p. 3
Name
The Nature of Science
rocks
7.
maps
2.
minerals
8.
mountains
3.
soil
4.
volcanoes
10.
weather
5.
earthquakes
11.
ocean water
6.
fossils
12.
objects in space
9.
2. Write a D if you disagree with the statement.
The Nature of Science
climates
The Nature of Science
Chapter Wrap-Up
Now that you have read the chapter, think about what you have learned and complete
the table below. Compare your previous answers with these.
1. Write an A if you agree with the statement.
Distinguish topics that Earth scientists study by listing specific
topics identified in this section.
1.
Date
3
After You
Read
• An important part of science is testing, or
experimenting.
A SE, p. 9
RE, p. 3
• Technology is useful only in the situation for
which it was designed.
D SE, p. 14
RE, p. 5
• People began studying weather in the 1800s.
D SE, p. 16
RE, p. 7
• Science can answer all of the questions that
can be asked.
D SE, p. 20
RE, p. 10
Review
Review the information you included in your Foldable.
Study your Science Notebook on this chapter.
Review daily homework assignments.
Re-read the chapter and review the charts, graphs, and illustrations.
Name
Date
Section 1 Science All Around
Working in
the Lab
I found this information
on page
.
SE, pp. 9–11
RE, pp. 4–5
Review the Self Check at the end of each section.
(continued)
Look over the Chapter Review at the end of the chapter.
S UMMARIZE I T
After reading this chapter, identify three things that you have
learned about the nature of science. Accept all reasonable responses.
Define the four types of factors in a science experiment. Identify
and describe each of them below.
Review Checklist
This list helps you assess what
you have learned and prepare
for your chapter tests.
1. Testing is an important part of scientific research. 2. A scientific hypothesis can
Independent
Variable
become a theory if it has been well tested and is supported by many experiments.
3. It is important to conduct scientific research in an ethical way.
variables that do not change
Dependent
Variable
8
The Nature of Science
the standard to which results can
be compared
Technology
I found this information
on page
.
SE, p. 14
RE, p. 5
Summarize transferable technology by defining the term. Then
provide examples by filling out the graphic organizer below.
Transferable technology is
technology designed for
one situation that is transferred to solve other problems
Radar and Sonar
originally
developed for
are now
used to
study
S YNTHESIZE I T
Identify three objects in your home or school that have not
been affected by technology. Accept all reasonable responses.
.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Study the definitions of vocabulary words.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Use this checklist to help you study.
Graphic Organizers
A variety of visual organizers help you
to analyze and summarize information
and remember content.
Almost everything is affected by technology in its construction or its parts. Students
should appreciate the importance of technology.
4
The Nature of Science
The Changing Su rface of Earth vii
Name
Date
Views of Earth
Before You Read
Before you read the chapter, respond to these statements.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
Before You
Read
Views of Earth
• All mountains form in the same way.
• Lines of longitude run parallel to
the equator.
• All maps of Earth distort the shapes
and sizes of landmasses.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Construct the Foldable as directed at the beginning of this chapter.
Science Journal
Assume that you want to build a home and have a satellite photo to guide you.
Describe where you would build your new home and why you would build at your
chosen location.
Student responses may vary. Green or red areas may be best for building a new
home. These areas tend to be less populated and less developed. Students
should choose their site carefully; green areas within the city are not usually
possibilities for building.
Views of Earth
1
Name
Date
Views of Earth
Section 1 Landforms
Skim the headings in Section 1. Write three questions that come to
mind from reading these headings. Accept all reasonable responses.
1. What are the different kinds of plains?
2. What are plateaus?
3. How do mountains form?
Review
Vocabulary Define landform to show its scientific meaning.
landform
natural feature of a land surface
New
Vocabulary Write the vocabulary term that matches each definition.
plain
plateau
flat, raised area of land made up of nearly horizontal rocks that
have been uplifted by forces within Earth
folded mountain
upwarped mountain
fault-block mountain
volcanic mountain
mountain in which rock layers are folded
mountain formed when blocks of Earth’s crust are pushed up by
forces inside Earth
mountain made of huge, tilted blocks of rock separated from
surrounding rock by faults
mountain formed when molten material reaches the surface
through a weak area of Earth’s crust
Academic
Vocabulary Use a dictionary to define expose.
expose
2
Views of Earth
to leave open or without protection; to reveal
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
large, flat area, often found in the interior regions of continents
Name
Date
Section 1 Landforms
Plains
I found this information
on page
.
(continued)
Distinguish two reasons that plains are useful for agriculture.
1. They are flat and have rich soil for growing crops.
2. Thick grass grows well, so plains are good places for cattle
and other grass-eating animals to live.
I found this information
on page
.
Compare and contrast coastal plains and interior plains.
Coastal Plains
Interior Plains
Location
Characteristics
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
I found this information
on page
.
Summarize key characteristics of the Great Plains.
The Great Plains are an example of a(n)
They are located
I found this information
on page
.
. The area is
grass and few trees
flat and dry
. The Great Plains
layers of sedimentary rocks
are made of
Plateaus
.
between the Mississippi River and
the Rocky Mountains
and covered with
interior plain
.
Compare and contrast plains and plateaus. Complete the Venn
diagram with at least three facts.
Plateaus
Plains
Both
ar
Views of Earth
3
Name
Date
Section 1 Landforms
Mountains
I found this information
on page
.
(continued)
Model the four types of mountains. Draw a diagram of each type.
Folded Mountain
Upwarped Mountain
Drawings should resemble
those in the textbook.
Have students work
in pairs to describe
the types of mountains. Some pairs may
find it useful to have
one student draw the
diagrams as the other
writes the summary.
Fault-Block Mountain
Volcanic Mountain
Summarize how mountains form. Give an example of each.
Folded Mountain: Strong forces within Earth squeeze rock
Upwarped Mountain: Blocks of Earth’s crust are pushed up by
forces inside Earth, and then the blocks erode. Example:
Adirondack Mountains
Fault-Block Mountain: Tilted blocks of rocks shift along faults.
Example: Grand Tetons or Sierra Nevada.
Volcanic Mountain: Hot, melted material reaches the surface
through a weak area of crust and builds up layer by layer.
CONNECT IT
Example: Mount Shasta, Mount St. Helens
Use a physical map to identify the landforms in your area.
Accept all reasonable responses.
4
Views of Earth
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
layers and cause them to fold. Example: Appalachian Mountains
Name
Date
Views of Earth
Section 2 Viewpoints
Preview the What You’ll Learn statements for Section 2. Predict
three topics that will be discussed in this section. Accept all
1. what latitude and longitude are
reasonable responses.
2. how latitude and longitude are used
3. how to find time and date in other time zones
Review
Vocabulary Define pole as it is used when describing Earth.
pole
either end of the axis of rotation of a sphere
New
Vocabulary Define each vocabulary term.
equator
imaginary line around Earth exactly halfway between the north
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
and south poles
latitude
prime meridian
longitude
distance in degrees north or south of the equator
imaginary line representing 0° longitude
distance in degrees east or west of the prime meridian
Academic
Vocabulary Use a dictionary to define parallel as an adjective. Then find a
sentence in Section 2 that contains the term.
parallel
being the same distance apart at all points; Sentence: Because
they are parallel, lines of latitude do not intersect, or cross, one
another.
Views of Earth
5
Name
Date
Latitude and
Longitude
I found this information
on page
.
Have students work
in pairs to complete
their drawings.
Provide a globe for
students to use to
practice finding the
latitude and longitude
of points on Earth.
(continued)
Model the system used to measure position on Earth.
• Draw a view of Earth.
• Label important features on the diagram with the following terms.
prime meridian
0° latitude
equator
north pole
south pole
90°S latitude
90°N latitude
Summarize how latitude and longitude are measured.
Latitude is measured by finding the distance in degrees north
or south of the equator
.
by finding the distance in
Longitude is measured
degrees east or west of the prime meridian
Degrees of latitude and longitude are divided into
and
6
Views of Earth
seconds
.
minutes
.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Section 2 Viewpoints
Name
Date
Section 2 Viewpoints
Time Zones
I found this information
on page
.
(continued)
Organize information about time zones. Complete the outline.
Time Zones
I. Measuring time
A. There are 24 hours in a day and 24 time zones.
B. Time is measured by tracking Earth’s movement in
relation to the Sun.
II. Characteristics of time zones
A. Each time zone is about 15° of longitude wide.
B. Each time zone is one hour different from the time zones
on each side of it.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
C. Some time zone boundaries are adjusted in local areas.
Calendar Dates
I found this information
on page
.
Summarize what a person should do when crossing the
International Date Line. Complete the cause-and-effect diagrams.
Travel west across the
International Date Line
move calendar forward
one day
Travel east across the
International Date Line
move calendar back
one day
S YNTHESIZE I T
Look at the map of time zones in your book. Infer why the
International Date Line does not follow the 180° meridian exactly.
Countries and other areas along the International Date Line want each day to be the same
throughout the entire country or area. The line has been adjusted to allow this.
Views of Earth
7
Name
Date
Views of Earth
Section 3 Maps
Scan the section headings, bold words, and illustrations. Write two
Accept all
facts that you discovered as you scanned the section.
reasonable responses.
Mapmakers
use
different
projections
to
make
maps of Earth.
1.
2. Topographic maps show changes in elevation.
Review
Vocabulary Define globe to show its scientific meaning.
globe
spherical representation of Earth
New
Vocabulary Use your book to define each vocabulary term.
conic projection
map projection made by projecting points and lines from a
globe onto a cone
contour line
map scale
map that models the changes in elevation of Earth’s surface
line on a map that connects points of equal elevation
relationship between distance on the map and distance on
Earth’s surface
map legend
part of a map that explains what the symbols used on the
map mean
Academic
Vocabulary Use a dictionary to define physical. Use physical in a sentence
to show its scientific meaning.
physical
having to do with things we experience through our senses;
Sample sentence: The map shows the physical features of
8
the region.
Views of Earth
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
topographic map
Name
Date
Section 3 Maps
(continued)
Map Projections
I found this information
on page
.
Define map. Then complete the statements below about map
projections.
a model of Earth’s surface
A map is
A map projection is made when
.
points and lines on the surface
of a globe are transferred to paper
All map projections
distort
.
the shapes and sizes of land-
masses to some extent.
I found this information
on page
.
Compare and contrast Mercator, Robinson, and conic
projections.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Mercator
Have students work
in pairs to identify
the features of the
different types of
projections.
Robinson
Conic
How is it
made?
Longitude
lines are
projected
parallel to
each other.
Latitude lines
are parallel,
but lines of
longitude curve
as on a globe.
Points and
lines are
projected
from a globe
onto a cone.
What does
it show
accurately?
Shapes of
continents are
accurate, but
sizes are
distorted.
Shapes and
land areas are
relatively
accurate.
Middle
latitude
regions are
shown
accurately.
How is it
used?
on ships
to show areas
and shapes
accurately
for road
maps and
weather
maps
Topographic
Maps
A topographic map shows how the elevation of Earth’s surface
I found this information
on page
.
changes. Such a map shows hills, valleys, and other landforms
Summarize the purpose of a topographic map.
as well as structures built by humans.
Views of Earth
9
Name
Section 3 Maps
Date
(continued)
I found this information
on page
.
Organize information about contour lines in the concept web.
These lines
connect points of
equal elevation.
Accept all
reasonable
responses.
The difference
in elevation between
two lines is the
contour interval.
Contour
Lines
Contour lines
placed close together
model a steep slope.
Summarize what a map scale and map legend show.
Map Scale
A map scale shows
the relationship
between distance
on the map and
distance on the
ground.
Map Legend
Map
Elements
A map legend explains
what each symbol
on a map means; the
legend usually appears
at the bottom or side
of the map.
Geologic Maps
Summarize what geologic maps are and how they are used.
I found this information
on page
.
Geologic maps show the arrangement and types of rocks at
Earth’s surface. Scientists use geologic maps to determine how
rock layers may look below the surface and can use the
information to locate natural resources.
CONNECT IT
If you were going to map your classroom, which map scale
would be better: 1 cm:1 m or 1 cm: 10 m? Explain your reasoning.
Accept all reasonable responses. I would use a scale of 1 cm:1 m. This way, I can show
small features such as a desk or chair more clearly.
10
Views of Earth
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
I found this information
on page
.
Index contours
are marked with
their elevations.
Name
Date
Tie It Together
Model
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Create a two-dimension physical map of your state in the space provided below.
Include the major landforms found in your state. Use symbols to indicate these
landforms on the map. Be sure to explain the symbols you use in a map legend.
Your map should be proportional to the actual size of your state. Include a map
scale to help others determine distances. Accept all reasonable responses.
Views of Earth
11
Name
Date
Views of Earth
Chapter Wrap-Up
Now that you have read the chapter, think about what you have learned and complete
the table below. Compare your previous answers with these.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
After You
Read
Views of Earth
• All mountains form in the same way.
D
• Lines of longitude run parallel to
the equator.
D
• All maps of Earth distort the shapes
and sizes of landmasses.
A
Review
Use this checklist to help you study.
Study your Science Notebook on this chapter.
Study the definitions of vocabulary words.
Review daily homework assignments.
Re-read the chapter and review the charts, graphs, and illustrations.
Review the Self Check at the end of each section.
Look over the Chapter Review at the end of the chapter.
S UMMARIZE I T
Identify three important ideas in this chapter.
Accept all reasonable responses. 1. Mountains form in a variety of ways. 2. Map
projections can distort the size and shape of landmasses. 3. Satellites allow people
to make digital maps of Earth’s surface.
12
Views of Earth
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Review the information you included in your Foldable.
Name
Date
Weathering and Soil
Before You Read
Before you read the chapter, respond to these statements.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
Before You
Read
Weathering and Soil
• Plants can break apart rock.
• Climate affects the rate at which
soil forms.
• Soil on steep slopes tends to be thicker
than soil at the bottom of a slope.
• Humans sometimes cause erosion to
occur faster than new soil can form.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Construct the Foldable as directed at the beginning of this chapter.
Science Journal
A tor is a pile of boulders left on land after the surrounding, weakened rock is worn
away. Write a poem about a tor. Use words in your poem that rhyme with the word tor.
Poems will vary.
Standing above the English moor;
Remnant of a landscape past.
The granite boulders of a tor;
Survivors of nature’s wrath.
Subject of myth and lore;
All that remains is weathered core.
Weathering and Soil
13
Name
Date
Weathering and Soil
Section 1 Weathering
Scan the headings of Section 1 to determine two main types of
weathering that will be discussed.
1. mechanical weathering
2. chemical weathering
Review
Vocabulary Define surface area, and use it in a scientific sentence. Accept all
surface area
area of a rock or other object that
reasonable responses.
is exposed to its surroundings; Sample sentence: Chopping an
onion increases the surface area of the onion and causes the
eyes to water.
New
Vocabulary Read the definitions below. Write the key term on the blank in the
weathering
mechanical weathering
ice wedging
chemical weathering
oxidation
climate
surface processes that break rock into smaller and smaller pieces
physical processes that break rock apart without changing its
chemical makeup
mechanical weathering process that occurs when water freezes in
the cracks in rock and expands
process in which chemical reactions dissolve the minerals in rock
or change them into different minerals
chemical weathering process that occurs as minerals are exposed
to air and water
the long-term pattern of weather that occurs in a particular area
Academic
Vocabulary Use a dictionary to define the term process as a noun.
process
14
Weathering and Soil
series of changes by which something develops
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
left column.
Name
Date
Section 1 Weathering
Weathering and
Its Effects
I found this information
on page
.
Mechanical
Weathering
I found this information
on page
.
(continued)
Sequence the sediment grain types in order of size.
Coarsest
Finest
Sand
Silt
Clay
Organize information by completing the outline below as you read.
Mechanical Weathering
I. Plants and Animals
A. Plants growing in cracks of rock enlarge the cracks.
B. Burrowing animals loosen sediment and push it to the
surface, where additional weathering occurs.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
II. Ice Wedging
A. occurs in temperate and cold climates
B. Water enters cracks in rocks, freezes, expands, and
breaks the rock apart.
C. most noticeable in mountains where warm days and
cold nights are common
III. Surface Area
A. Mechanical weathering reduces rock to smaller and
smaller pieces.
B. Smaller pieces have more surface area than the
original rock.
C. As surface area increases, more rock is exposed to
chemical weathering.
Weathering and Soil
15
Name
Date
Section 1 Weathering
Chemical
Weathering
(continued)
Sequence steps to explain how carbon dioxide causes chemical
weathering. Accept all reasonable responses.
I found this information
on page
.
Chemical Weathering by Carbonic Acid
1. Water reacts with carbon dioxide in the air or soil.
2. A weak acid called carbonic acid forms.
3. The carbonic acid reacts with some minerals.
4. Over time, the reaction causes the minerals to dissolve.
Synthesize the effects of climate and rock type on the rate of
weathering in the table below. Accept all reasonable responses.
I found this information
on page
.
Factors that Affect the Rate of Weathering
Factor
Effects
climate
Chemical weathering is rapid in warm, wet climates.
High temperatures speed up chemical reactions
that occur in water.
Mechanical weathering often is rapid in cold
climates that have frequent freezing and thawing.
rock type
Some types of rock, such as granite, weather
more slowly in wet climates than other types,
such as marble.
Analyze how oxygen can cause chemical weathering. Discuss where
you have seen oxidation around your home.
Accept all reasonable responses. Oxidation occurs when some
minerals that contain iron are exposed to oxygen and water. This
results in a new material that resembles rust. Oxidation can take
place in rocks or on some metals exposed to water and oxygen:
bikes, nails, or barbeque set.
16
Weathering and Soil
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Effects of
Climate
Name
Date
Weathering and Soil
Section 2 The Nature of Soil
Predict two things that might be discussed in this section on the
basis of its title. Accept all reasonable answers.
1. what soil is made of
2. different kinds of soil
Review
Vocabulary Define the term profile.
profile
vertical slice through rock, sediment, or soil
New
Vocabulary Use your book or a dictionary to define the following terms.
soil
mixture of weathered rock, decayed organic matter, mineral
fragments, water, and air
humus
dark-colored material that forms when organic matter
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
partly decays
horizon
soil profile
litter
leaching
layer of soil
the horizons of a soil
leaves, twigs, and other surface organic material
removal of minerals that have been dissolved in water
Academic
Vocabulary Use a dictionary to define indicate.
indicate
to be or give a sign of
Weathering and Soil
17
Name
Date
Section 2 The Nature of Soil
Formation of Soil
I found this information
on page
.
(continued)
Complete the graphic organizer to show the five factors that affect
soil formation.
length of time
that rock has been
weathering
climate
Factors Affecting Soil Formation
slope of
the land
I found this information
on page
.
mineral
organic
fragments matter
air
water
Symbols should be representative of each component.
Compare and contrast dry soil and moist soil. Create sketches in
the top row, and write descriptions in the bottom row.
Dry Soil
Moist Soil
Accept all reasonable responses. The components
of soil will be similar except for what is filling the spaces
between soil particles.
A dry soil has pore spaces
that are almost completely
filled with air.
18
Weathering and Soil
The pores of a moist soil are
partly filled with water.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
rock
My Soil
Symbol
I found this information
on page
.
type of
rock
Identify the five components of soil, and create a symbol to
represent each.
Component
of Soil
Composition
of Soil
type of
vegetation
Name
Date
Section 2 The Nature of Soil
Soil Profile
I found this information
on page
.
I found this information
on page
.
(continued)
Model a soil profile by drawing and labeling it below.
Profile should include three distinct layers.
Possible descriptions:
• Top layer: dark, fertile, contains humus
• Middle layer: less fertile than top layer; may
contain material leached from the top layer
• Lower layer: often the thickest; contains coarse
sediment and parent material of soil
Organize information about soil structure in the concept map.
Types of Peds
platy
blocky
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
granular
Soil Types
I found this information
on page
.
prismatic
Summarize information about how soil varies in different regions.
Region
Soil
desert
contain little organic matter;
thinner soil than wetter climates
prairie
grasses add large amounts of organic matter;
thick, dark A horizons
temperate
forest
less organic matter and thinner A horizons than
prairie soil
CONNECT IT
Analyze relationships between organisms and soil. Describe how
organisms use soil and how organisms affect soil. Accept all reasonable answers.
Some organisms grow in, live in, or feed on soil. Organisms affect soil by contributing
organic matter to the soil and by mixing the soil.
Weathering and Soil
19
Name
Date
Weathering and Soil
Section 3 Soil Erosion
Skim the headings and the boldfaced terms in Section 3. Identify
three facts about soil erosion and ways to reduce its occurrence.
1. Ground cover protects soil from erosion.
Accept all reasonable
responses.
2. Erosion of topsoil reduces its quality.
3. No-till farming and contour farming reduce soil erosion.
Review
Vocabulary Use erosion in a scientific sentence.
erosion
Erosion can occur when it rains hard enough to cause runoff.
New
Vocabulary Define the following terms. Then use each term in an original
scientific sentence.
no-till farming
when farmers leave plants in a field over the winter months;
Sample sentence: No-till farming provides cover to protect
contour farming
planting along the natural contours of the land; Sample
sentence: Contour farming is often used in hilly areas.
terracing
method of farming in which steep-sided, level-topped areas
are built into the sides of steep hills and mountains; Sample
sentence: Terracing is useful when farming mountainous parts
of the world.
Academic
Vocabulary Define the term compensate as it refers to soil.
compensate
20
Weathering and Soil
to make up for
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
the soil.
Name
Date
Section 3 Soil Erosion
Soil—An
Important
Resource
I found this information
on page
.
Causes and
Effects of
Soil Erosion
(continued)
Evaluate why soil erosion is a serious problem for agriculture.
Accept all reasonable responses. Erosion can wash soil from
the A horizon, which is the richest layer of soil. This means
that the soil that plants grow best in is lost.
Organize information on the causes and effects of soil erosion by
completing the diagram below.
Causes
Effects
I found this information
on page
.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
agricultural
cultivation
topsoil
is lost
forest
harvesting
nutrients and
waterholding capacity
are reduced
overgrazing
I found this information
on page
.
soil is
damaged
Soil Erosion
Identify the causes and effects of excess sediment.
is caused
by
Excess
sediment
can
affect
strip mining or
construction exposing
large areas of land
streams and the
environment
Weathering and Soil
21
Name
Date
Section 3 Soil Erosion
Preventing
Soil Erosion
I found this information
on page
.
(continued)
Summarize methods of preventing soil erosion.
Preventing Soil Erosion
Strategy
Manage crops
Methods
1. Plant shelter belts of trees to break the
force of the wind.
2. Plant crops to cover ground after main
harvest.
3. Use no-till farming to avoid plowing
fields.
Reduce erosion
on slopes
1. Practice contour farming by planting
along the natural contours of the land.
Reduce erosion
on exposed soil
1. During construction projects, spray
water on bare ground to reduce erosion
by the wind.
2. After construction, add topsoil and plant
trees to stabilize soil.
3. After strip-mining, flatten slopes and
plant vegetation.
CONNECT IT
Identify ways to prevent erosion that are probably used in your
community and explain why they are used. Accept all reasonable answers.
In all communities, methods for reducing erosion of exposed soil would be applicable
because of construction of homes and roads. The various other ways of reducing
erosion would be common for farming communities with varying terrains.
22
Weathering and Soil
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
2. Build terraces.
Name
Date
Tie It Together
Model
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Recall evidence of erosion that you have seen in your community. Then create a
model to demonstrate how the erosion probably occurred. You may make a working
three-dimensional model that you can demonstrate for the class. You may represent
your model with a labeled drawing. Describe how the model can be changed to
prevent erosion.
Weathering and Soil
23
Name
Date
Weathering and Soil
Chapter Wrap-Up
Now that you have read the chapter, think about what you have learned and complete
the table below. Compare your previous answers with these.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
After You
Read
Weathering and Soil
• Plants can break apart rock.
A
• Climate affects the rate at which
soil forms.
A
• Soil on steep slopes usually is thicker
than soil at the bottom of a slope.
D
• Humans sometimes cause erosion to
occur faster than new soil can form.
A
Review
Review the information you included in your Foldable.
Study your Science Notebook on this chapter.
Study the definitions of vocabulary words.
Review daily homework assignments.
Re-read the chapter and review the charts, graphs, and illustrations.
Review the Self Check at the end of each section.
Look over the Chapter Review at the end of the chapter.
S UMMARIZE I T
After reading this chapter, identify three things that you have
learned about weathering and soil. Accept all reasonable responses.
1. Mechanical weathering and chemical weathering affect Earth’s surface. 2. Soil is
constantly forming from solid rock. 3. When forests are removed, soil is exposed and
erosion increases.
24
Weathering and Soil
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Use this checklist to help you study.
Name
Date
Erosional Forces
Preview
Before you read the chapter, respond to these statements.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
Before You
Read
Erosional Forces
• Glaciers can erode rocks and soil.
• Human activity can increase erosion.
• Steep slopes can be unsafe for structures
such as houses.
• Planting vegetation can increase erosion.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Construct the Foldable as directed at the beginning of this chapter.
Science Journal
Name three major landforms around the world. Hypothesize what erosional forces
helped shape them. Use sketches to help you think about the processes.
.
Erosional Forces
25
Name
Date
Erosional Forces
Section 1 Erosion by Gravity
Predict what you will learn about erosion after looking at each
illustration in Section 1 of your book. Accept all reasonable
I predict that I will learn that gravity pulls land
responses.
downward in slump, creep, rock slides, and mudflows.
Review
Vocabulary Write a sentence using the word sediment to show its scientific
meaning. Accept all reasonable responses.
sediment
The river deposited sediment along its banks.
New
Vocabulary Define the following key terms by using your book or a
dictionary.
erosion
process in which surface materials are worn away and
deposition
dropping of sediment that occurs when an agent of erosion
can no longer carry its load
mass movement
any type of erosion that occurs as gravity moves rock or
sediment downslope
slump
a type of mass movement that occurs when a mass of
sediment slips down along a curved surface
creep
a type of mass movement in which sediment moves downslope
very slowly
Academic
Vocabulary Use a dictionary to define the word structure.
structure
anything that is built; a home or other building, a molecule's
structure
26
Erosional Forces
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
transported from one place to another
Name
Date
Section 1 Erosion by Gravity
Erosion and
Deposition
I found this information
on page
.
(continued)
Identify four major agents of erosion.
1. gravity
2. water
3. wind
4. glaciers
Summarize how energy affects the ability of agents of erosion to
carry and drop sediment. Then describe how this occurs with water.
Agents of erosion carry sediment only when they have
enough energy of motion to do so. They drop sediment as
they lose energy.
Water: Rivers and streams carry sediment. The sediment
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
is deposited at places where the water slows, such as a delta
or a bend in the river.
Mass Movement
I found this information
on page
.
Compare and contrast characteristics of mass movements by
completing the following chart.
Mass Movements
Types
Description
Slump
A mass of sediment slips along a curved
surface.
Mudflow
A mixture of sediment and water flows down
a slope.
Rock slide
Layers of rock slip downslope suddenly.
Creep
Sediment moves downhill slowly.
Rockfall
Blocks of rock break loose and tumble through
the air.
Erosional Forces
27
Name
Date
Section 1 Erosion by Gravity
I found this information
on page
.
Consequences of
Erosion
(continued)
Model what a slope would look like before and after a mudflow.
“Before” drawings
should show trees
and other vegetation
on a hillside.
“After” drawings should
show a mass of soft land
that has flowed downward
into a fan shape, with
remnants of vegetation
at the bottom.
Before
After
Analyze ways to reduce erosion on steep slopes. Complete the
graphic organizer below.
Ways to reduce erosion
on steep slopes
planting
vegetation
inserting
drainage
pipes
building
walls
COMPARE IT
Model a way to build a house on a hillside. Draw the house and
show methods to protect the house from erosion caused by gravity.
Accept all reasonable responses.
The house will have drainage tile around it that carries water away so that
slump does not occur. The house will be surrounded with plants with
deep roots, and a wall will be built below the house to retain the soil.
28
Erosional Forces
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
I found this information
on page
.
Name
Date
Erosional Forces
Section 2 Glaciers
Scan the illustration headings in Section 2. Write three true
statements about glaciers on the lines below. Accept all reasonable
responses.
A glacier is a large mass of ice and snow moving on land under
its own weight. Eskers are glacial deposits formed by meltwater.
Glacial erosion and deposition created many landforms on Earth.
Review
Vocabulary Define plasticlike using your book.
plasticlike
not completely solid or liquid; capable of being molded or
changing form
New
Vocabulary Write a scientific sentence for each vocabulary word.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
glacier
The glacier formed as snow and ice accumulated over many
hundreds of years.
plucking
Plucking caused rocks to accumulate in the ice at the bottom
of the glacier.
till
Some farmland in the Midwest is made up of till that was left
behind when glaciers retreated.
moraine
Material piled up at the end of the glacier, forming a moraine.
outwash
The meltwater from the glacier deposited a fan-shaped outwash
deposit.
Academic
Vocabulary Define accumulate by using a dictionary.
accumulate
to gather, pile up, or collect
Erosional Forces
29
Name
Section 2 Glaciers
Date
(continued)
How Glaciers
Form and Move
I found this information
on page
.
Sequence the steps of glacier formation and movement. The first
step has been completed for you. Accept all reasonable responses.
1. When snow doesn’t melt, it piles up.
2. The increasing weight of snow compresses the lower
layers into ice.
3. The ice becomes plasticlike.
4. The mass slowly begins to flow away from its source.
Contrast two ways that glaciers erode rock. Accept all reasonable
responses.
I found this information
on page
.
Plucking
Scouring
1. Melting occurs at the
bottom of a glacier.
1. Glaciers transport
sediment and rock.
2. Water flows into cracks
in rocks.
2. Sediment and rock scour the
land as the glacier moves.
3. The water refreezes and
extends the cracks.
3. Striations and grooves
form.
4. The ice lifts out pieces
of the rock.
Ice Depositing
Sediment
I found this information
on page
.
30
Erosional Forces
Summarize the types of glacier deposits in the chart below.
Mass Movements
Type
Consists of
Deposited by
Example of
landform that
is left behind
Till
a mixture of
rocks, sand,
clay, and silt
glacier, left
behind when
it melts
moraine, a
ridge of rocks
and soil
Outwash
sand and
gravel
water from a
melting glacier
fan-shaped
layer of sand
and gravel
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Ice Eroding Rock
Name
Date
Section 2 Glaciers
(continued)
Continental
Glaciers
I found this information
on page
.
Identify key facts about continental glaciers. Complete the
concept map below.
Description
Location Today
huge sheets of ice
and snow
mostly near the poles
in Antarctica and
Greenland
Continental
Glaciers
Last Ice Age
covered as much as 28 percent of Earth’s surface;
reached maximum extent about 18,000 years ago
Valley Glaciers
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
I found this information
on page
.
Create a labeled diagram of a mountain that has been eroded by
valley glaciers.
Drawings might include a cirque, a horn, arêtes,
and a U-shaped valley. They also might include
a hanging valley.
S YNTHESIZE I T
Outside of a town in the Midwest is a long, winding ridge
made of sand and gravel. Hypothesize how this landform may have formed.
Accept all reasonable responses. This may be an esker created by a melting glacier.
A river may have formed in the melting ice, depositing sand and gravel in its channel.
When the glacier melted, a ridge of these deposits remained.
Erosional Forces
31
Name
Date
Erosional Forces
Section 3 Wind
Skim the headings in Section 3. Write three questions that occur
to you. Accept all reasonable responses.
1. What does wind erosion do?
2. How can wind erosion be reduced?
3. What is the difference between loess and dunes?
Review
Vocabulary Define friction using your book or a dictionary.
friction
a force that opposes the motion of an object when the object
is in contact with another object or surface
New
Vocabulary Read each definition. Write the correct vocabulary word to
abrasion
when windblown sediment strikes rock, the surface of the rock gets
scraped and worn away
loess
wind-blown deposits of fine-grained sediments are called
dune
a mound of sand drifted by the wind.
deflation
wind removes small particles such as silt and sand and leaves
behind heavier, coarser material.
Academic
Vocabulary Write a sentence that shows the meaning of the word eventual.
eventual
Accept all reasonable responses. Deposition of sediment is the
eventual result of erosion.
32
Erosional Forces
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
match on the blank in the left column.
Name
Section 3 Wind
Date
(continued)
Wind Erosion
I found this information
on page
.
Contrast two ways wind differs from other agents of erosion.
1. Wind can pick up light, loose material. It usually cannot pick
up heavy sediment.
2. Wind can deposit sediment over a larger area and thousands
of kilometers away from the source.
Sequence deflation and abrasion in the flowchart. Make a sketch
for the process that occurs in each box.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Deflation
I found this information
on page
.
Abrasion
Drawing
Drawing
Description
Description
Wind blows across
loose sediment, picking
up small particles such
as sand and silt.
Windblown sediment
strikes rock, scraping
it and wearing it away.
Contrast sandstorms and dust storms in the chart.
Sandstorms
Dust Storms
What particles
are carried by
the storm?
Sand grains are
carried.
Silt and clay-sized
particles are carried.
What happens?
Wind blows sand
grains into a low
cloud.
A fast wind lifts
lightweight particles
and carries them
over long distances.
Erosional Forces
33
Name
Date
Section 3 Wind
(continued)
Reducing Wind
Erosion
I found this information
on page
.
Summarize how plants help conserve soil. Make a sketch to show
each effect in the boxes at right.
1. Windbreaks: Plant trees to
prevent soil erosion. Trees reduce
the energy of the wind. They also
trap snow, which increases the level
of moisture in the soil.
2. Roots: Grass roots are shallow
and slender and have many fibers.
They twist and turn between soil
Deposition
by Wind
I found this information
on page
.
Complete the statements about loess and sand dunes.
Loess forms when wind blows across glacial outwash areas . When
the sediment is dropped, it forms
fine, thick, yellowish-brown
deposits. Loess deposits often become
often form in
fertile
soils. Sand dunes
deserts . After the dunes form, they move in the
direction that the
wind
blows. Sand blows up the
side of the dune. It then falls down the
This process causes the
dune
steep
gentle
side of the dune.
to move slowly across the desert.
S YNTHESIZE I T
During the 1930s, wind eroded soil from much of the southcentral United States (the Dust Bowl). Infer what farming practices might have contributed
to the Dust Bowl. Summarize how farmers could have protected their farms.
Accept all reasonable responses. Overgrazing and excess tilling contributed to the
creation of the Dust Bowl. Farmers could have maintained ground cover to hold the soil
in place and planted trees for windbreaks.
34
Erosional Forces
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
particles and hold soil in place.
Name
Date
Tie It Together
Plan Articles
Imagine that you are a reporter for a newspaper. The town where you live is located
near a moraine and along the shore of a large lake. Plan a series of two articles that
will explain
i. how erosion and deposition shaped the town’s land
ii. what dangers the town may face from erosion in the future.
Accept all reasonable responses.
Article 1
Topic:
Erosion and deposition and the town’s history
Headline: Glaciers Shaped Town’s Landscape
Key Points for Article:
Students might describe how the moraine formed at the edge of a glacier and how the
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
glacier deposited a layer of till over the land.
Article 2
Topic:
Mass wasting
Headline: Slump Threatens Lakeshore
Key Points for Article:
Students might describe waves undercutting steep cliffs and sediment slumping
downward into the lake. Some students may suggest ways to reduce erosion, such
as installing breakwaters.
Erosional Forces
35
Name
Date
Erosional Forces
Chapter Wrap-Up
Now that you have read the chapter, think about what you have learned and complete
the table below. Compare your previous answers with these.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
After You
Read
Erosional Forces
• Glaciers can erode rocks and soil.
A
• Human activity can increase erosion.
A
• Steep slopes can be unsafe for structures
such as houses.
A
• Planting vegetation can increase erosion.
D
Review
Review the information you included in your Foldable.
Study your Science Notebook on this chapter.
Study the definitions of vocabulary words.
Review daily homework assignments.
Re-read the chapter and review the charts, graphs, and illustrations.
Review the Self Check at the end of each section.
Look over the Chapter Review at the end of the chapter.
S UMMARIZE I T
After reading this chapter, identify three things that you have
learned about erosional forces. Accept all reasonable responses.
Gravity, wind, water, and glaciers are agents of erosion. Erosion has shaped Earth’s
surface. There are ways to reduce erosion in some places, such as by planting grasses
and trees.
36
Erosional Forces
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Use this checklist to help you study.
Name
Date
Water Erosion and Deposition
Before You Read
Before you read the chapter, respond to these statements.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
Before You
Read
Water Erosion and Deposition
• The presence of plants can affect how much
water runs off the land.
• When a river forms, its course never changes.
• Water that soaks into the ground becomes part
of a system, just as water above ground does.
• Beaches are always made of pieces of rock.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Construct the Foldable as directed at the beginning of this chapter.
Science Journal
Hoodoos are narrow towers of rock. What processes might have formed hoodoos?
What will happen if this process continues?
Accept all reasonable responses. Students should include erosion by water, ice,
or wind.
Water Erosion and Deposition
37
Name
Date
Water Erosion and Deposition
Section 1 Surface Water
Skim Section 1 of your book and read the headings. Write three
questions that come to mind. Try to answer your questions as
you read. Accept all reasonable responses.
1. What factors affect runoff?
2. What causes erosion?
3. What is a drainage basin?
Review
Vocabulary Define erosion.
erosion
transport of surface materials by agents such as gravity, wind,
water, or glaciers
New
Vocabulary Write a paragraph that uses each vocabulary term in a way that
drainage basin
meander
shows its scientific meaning. Accept all reasonable responses.
When rain falls, some of the water does not soak into the
ground or evaporate. It flows over Earth’s surface as runoff.
This runoff often flows into rivers or streams. Rivers and
streams collect runoff that falls in their drainage basins. As
rivers flow, they erode their banks in twisting patterns, forming
meanders.
Academic
Vocabulary Use your book or a dictionary to define likewise.
likewise
38
in the same way
Water Erosion and Deposition
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
runoff
Name
Date
Section 1 Surface Water
Runoff
I found this information
on page
.
(continued)
Distinguish four factors that determine how much runoff occurs
after rain falls.
Factors Affecting Runoff
amount of
rain
Water Erosion
I found this information
on page
.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
slope of
land
Causes
Effects
Rill
heavy rain falling on
a slope
groove or small ditch
Gully
heavy rain falling on
a slope
broader, deeper rill
channel
Sheet
water flowing as thin,
wide sheets outside
a channel
thin layer of water that
carries away sediment
Stream water continuing to flow
along a low place
River System
Development
I found this information
on page
.
presence of
vegetation
Summarize the causes and effects of four types of surface water
erosion in the chart below.
Type
Have groups of
students investigate
ways that farmers
prevent or slow the
erosion of soil.
length of
time
light sediment is carried
and heavy sediment is
rolled; rock is worn away
by abrasion
Scan the map of drainage basins in the United States in your text.
Identify three major drainage basins.
1. Mississippi River Drainage Basin
2. Colorado River Drainage Basin
3. Columbia River Drainage Basin
Water Erosion and Deposition
39
Name
Date
Section 1 Surface Water
Stages of Stream
Development
(continued)
Sequence the stages of stream development. Complete the flow
chart to identify the key features of each stage.
I found this information
on page
.
Young Streams
may have rapids and waterfalls; high-energy water;
erode stream bottom faster than sides
Mature Streams
meanders, floodplain; erosion occurs along sides of stream,
causing curves and meanders
Old Streams
broad, flat floodplain
I found this information
on page
.
Contrast the roles and locations of dams and levees.
Dams are built across rivers to control water flow downstream.
Levees are built along the sides of rivers to keep the water
inside the rivers’ banks.
Deposition by
Surface Water
I found this information
on page
.
Summarize how rivers deposit sediments. Describe how deltas and
alluvial fans form.
As water slows, it
deposits its load of soil and rock
These deposits form a delta when
or lake
water flows into an ocean
. They form an alluvial fan when
flows from a mountain valley onto an open plain
water
.
S YNTHESIZE I T
A broad, flat river flows slowly along its bed while a young,
swift stream rushes past. Explain which one would probably deposit more sediment.
Accept all reasonable responses. A mature stream would probably deposit more sediment
because it moves more slowly.
40
Water Erosion and Deposition
.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Too Much Water
Name
Date
Water Erosion and Deposition
Section 2 Groundwater
Scan the headings in Section 2. Then predict three topics that will
be covered in this section. Accept all reasonable responses.
1. wells
2. springs
3. geysers
Review
Vocabulary Define pore.
pore
small, or minute, opening in rock or soil
New
Vocabulary Use your book to define the following terms.
permeable
describes soil and rock with connecting pores through which
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
water can flow
aquifer
water table
geyser
layer of permeable rock that allows water to flow through
upper surface of the zone of saturation
hot spring that erupts periodically and shoots water and steam
into the air
Academic
Vocabulary Use your book or a dictionary to define underlie.
underlie
to lie beneath
Water Erosion and Deposition
41
Name
Date
Section 2 Groundwater
I found this information
on page
.
I found this information
on page
.
Summarize how groundwater collects. Complete the graphic
organizer.
Soil is made of fragments
of rocks and minerals with
spaces between them.
Water soaks into the ground and
collects in the pores and empty
spaces in the soil.
Create a drawing that shows how groundwater flows. Label the
impermeable layer, permeable layer, water table, and zone of
saturation. Use arrows to show how the groundwater flows.
Drawings should resemble
those in the textbook.
Students should indicate the zone of saturation
above the impermeable layer.
Water Table
I found this information
on page
.
42
Organize information about wells and springs. Complete the chart.
Water
Source
Important Features
Regular
well
must be past the top of the water table; needs
a pump to bring water to the surface
Artesian
well
aquifer must be between two impermeable layers
that slope; water in upper end puts pressure on
the water below
Spring
occurs when water table meets Earth’s surface;
often found on hillsides; often used as a source
of freshwater
Water Erosion and Deposition
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Groundwater
Systems
(continued)
Name
Date
Section 2 Groundwater
Water Table
I found this information
on page
.
The Work of
Groundwater
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
I found this information
on page
.
This is a good
partner activity.
(continued)
Sequence the events that cause a geyser to erupt. Complete the
flow chart.
1. Water is heated to
high temperatures
underground.
2. The hot water expands,
forcing some water from
the ground.
3. The remaining water
boils and turns into
steam.
4. The steam shoots from
a hole in the ground.
Complete the concept map to identify ways that groundwater
shapes land.
Caves
Stalactites
Water mixes with
carbon dioxide gas to
form carbonic acid, which
dissolves limestone to
form an underground
opening.
Water carrying
calcium evaporates
while hanging from a
cave ceiling.
Groundwater
shapes land.
Stalagmites
Sinkholes
Water drops fall
from a cave ceiling
and evaporate, leaving
calcium deposits.
These form when
underground rock near
the surface dissolves or
a cave collapses.
CONNECT IT
Aquifers are important natural resources. Due to human activity,
the levels of some aquifers have dropped over time. What problems can this cause
for humans? Accept all reasonable responses.
Dropping water levels make it more difficult for wells to reach groundwater sources,
a situation which can cause water shortages.
Water Erosion and Deposition
43
Name
Date
Water Erosion and Deposition
Section 3 Ocean Shoreline
Scan Section 3 of your text using the checklist below.
Read all section titles.
Read all bold words.
Look at all pictures and labels.
Think about what you already know about waves and shorelines.
Write three facts you discovered about ocean shorelines as you
scanned the section. Accept all reasonable responses.
1. Three major forces that change shorelines are waves,
currents, and tides.
Beaches
are made of different materials.
2.
3. The same forces that build barrier islands erode them.
Review
Vocabulary Define spring tide.
spring tide
tide of increased range that occurs twice monthly at the
New
Vocabulary Use your book to define the following terms.
longshore current
beach
current that runs parallel to the shoreline
deposit of sediment whose materials vary in size, color,
and composition
Academic
Vocabulary Use your book or a dictionary to find the meaning of transport
as a verb. Then write a sentence using the term.
transport
to carry from one place to another; Sample sentence:
A longshore current transports sand along a beach.
4 4
Water Erosion and Deposition
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
new and full phases of the Moon
Name
Date
Section 3 Ocean Shoreline
The Shore
I found this information
on page
.
(continued)
Complete the graphic organizer below to identify how shoreline
erosion occurs.
Causes of Shoreline Erosion
Encourage students
who have been to
a beach to share
their impressions
of the area.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Rocky Shorelines
I found this information
on page
.
Waves
Longshore Currents
Tides
crash against
shoreline,
breaking rocks into
smaller pieces
run parallel
to shoreline
and carry
sediment
create currents
that carry
sediment toward
or away from
the shore
Sequence three steps in the erosion process of a rocky shoreline.
Create a sketch to help you remember each step.
1. Waves crash
against the rocks
and cliffs, wearing
away the rock.
Accept all reasonable steps
and sketches.
2. Softer rock erodes
first, leaving
islands of harder
rock.
3. Harder rocks wear
away over time.
Sediment is carried
away by longshore
currents.
Water Erosion and Deposition
45
Name
Date
Section 3 Ocean Shoreline
Sandy Beaches
I found this information
on page
.
(continued)
Summarize how beach sand forms.
Waves grind rocks and seashells into pieces. The waves push
the pieces together, breaking them into smaller pieces. The
grinding also polishes the corners of the pieces and makes
them smoother.
I found this information
on page
.
Analyze ways that beaches can change. Accept all reasonable
Cause
Effect
Tides and currents
carry sand
Storms and waves
damage beaches
Human activity
responses.
construction can damage beaches
Analyze how barrier islands form and change. Complete the
outline.
I. How barrier islands form
A. Start as underwater sand ridges
B. Sediment added by hurricanes and storms
II. How barrier islands change
A. Wind blows loose sand into dunes.
B. Storms and waves carry sand away, eroding the island.
S YNTHESIZE I T
Which shoreline feature would you expect to last longest: a
rocky shoreline, a sandy beach, or a barrier island? Which would you expect to last
the shortest time? Explain your response. Accept all reasonable responses.
A rocky shoreline will probably last longest because harder rocks take a longer time to
erode as a result of wave action. The barrier island would last the shortest time because
it is easily eroded.
46
Water Erosion and Deposition
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Sand Erosion
and Deposition
Name
Date
Tie It Together
Test Soil Permeability
In a small group, collect several different types of soil or rock, such as gravel, sand,
and clay. Test the permeability of each sample by following the process below.
1. Cut the top from a plastic 2-liter bottle. Be sure to follow safety procedures
when cutting.
2. Place about 10 cm of the material to be tested in the bottom part of the bottle.
3. Pour 100 ml of water into the bottle. Use a stopwatch to determine how long it
takes the water to soak into the material. Observe the substance carefully until
there is no water collected on the surface of the soil or gravel.
4. Record your results in the table below.
5. Remove the material from the bottle, and rinse and dry the bottle thoroughly.
Then repeat steps 1–4 with the other materials you chose.
Material
Time
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Accept all properly
recorded observations.
Given your results, which material would you use in the yard of a house built on a low
area? Explain your response. Accept all reasonable responses.
The most permeable material would allow water to soak into the ground more easily,
reducing the chance that water would reach the house.
Water Erosion and Deposition
47
Name
Date
Water Erosion and Deposition
Chapter Wrap-Up
Now that you have read the chapter, think about what you have learned and complete
the table below. Compare your previous answers with these.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
After You
Read
Water Erosion and Deposition
• The presence of plants can affect how much
water runs off the land.
A
• When a river forms, its course never changes.
D
• Water that soaks into the ground becomes part
of a system, just as water above ground does.
A
• Beaches are always made of pieces of rock.
D
Use this checklist to help you study.
Review the information you included in your Foldable.
Study your Science Notebook on this chapter.
Study the definitions of vocabulary words.
Review daily homework assignments.
Re-read the chapter and review the charts, graphs, and illustrations.
Review the Self Check at the end of each section.
Look over the Chapter Review at the end of the chapter.
S UMMARIZE I T
After reading this chapter, identify three things that you have
learned about erosion and deposition by water. Accept all reasonable responses.
1. Rills, gullies, sheets, and streams all cause water erosion. 2. Streams can be young,
mature, or old. 3. Groundwater moves under the surface through permeable rock
and soil.
48
Water Erosion and Deposition
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Review
Name
Date
Clues to Earth’s Past
Before You Read
Before you read the chapter, respond to these statements.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
Before You
Read
Clues to Earth’s Past
• The footprint of a dinosaur is considered
a fossil.
• Scientists use fossils to learn what an
environment was like long ago.
• The oldest rock layer is always the one
found on top.
• Scientists can determine the age of
some rocks.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Construct the Foldable as directed at the beginning of this chapter.
Science Journal
List three fossils that you would expect to find a million years from now in the place
you live today.
Responses will vary, but should make sense for the local environment. If near
water, include mollusks. Insects in amber are also likely. Point out that animal
bones are unlikely to survive for fossilization. Leaf impressions or pollen grains
may be possible.
Clues to Earth’s Past
49
Name
Date
Clues to Earth’s Past
Section 1 Fossils
Skim Section 1 of your book. Read the headings and examine the
illustrations. Write three questions that come to mind. Accept all
1. How do fossils form?
reasonable responses.
2. What are carbon films?
3. How does coal form?
Review
Vocabulary Define paleontologist to show its scientific meaning.
paleontologist
scientist who studies fossils
New
Vocabulary Define the following terms to show their scientific meaning.
carbon film
cast
fossils in which the spaces inside are filled with minerals from
groundwater
thin film of carbon residue preserved as a fossil
type of fossil that forms when crystals fill a mold or sediments
wash into a mold and harden into rock
index fossils
remains of species that existed on Earth for a relatively short
period of time, were abundant, and were widespread geographically
Academic
Vocabulary Define emerge to show its scientific meaning.
emerge
50
Clues to Earth’s Past
to come out; to appear
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
permineralized
remains
Name
Section 1 Fossils
Date
(continued)
Formation of
Fossils
Complete the table to describe the two conditions that improve the
chances of fossil formation. Give an example of each.
I found this information
on page
.
Types of
Preservation
Condition
Example
must be protected from scavengers
and other harmful forces
quick burial
has hard parts, which are more likely
to survive than soft parts
bones, shells,
or teeth
Create a concept web to summarize the types of preservation.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
I found this information
on page
.
Students may find it
easier to make a list
of the concepts they
want to include before
joining them in a web.
I found this information
on page
.
Accept all reasonable responses.
Topics that should be included are
permineralized remains, carbon films,
molds, casts, and original remains.
Sequence the steps involved in the making of the cast of a shell.
Sediment
buries shell.
Sediment
surrounding
shell turns
into rock.
Water entering
through pores
dissolves shell.
Mold results.
Mold fills
with sediment
or minerals.
Cast results.
Clues to Earth’s Past
51
Name
Section 1 Fossils
Date
(continued)
Index Fossils
I found this information
on page
.
Summarize the three characteristics of index fossils.
1. The species existed for a short time.
2. The organisms were numerous.
3. The species lived in many places.
Analyze why index fossils are more useful to paleontologists than
many other fossils.
They are useful because the species they represent only lived
for a short time. This means that any rock containing that fossil
formed during that short time. Scientists can use them to
estimate the age of rock layers.
Organize the kinds of information about ancient environments that
scientists can learn from fossils. Complete the graphic organizer.
I found this information
on page
.
Have students work in
pairs to identify what
paleontologists can
learn from fossils.
Information about environment
revealed by fossils
if area was land
or covered
by water
past climate
of the area
in areas that
were covered
by water, depth
of the water
CONNECT IT
You find a fossil shell in a layer of rock. It appears to be a clam.
What type of rock must the rock layer be? What type of environment would the
animal have lived in? Accept all reasonable responses.
The rock is sedimentary rock, and the area was under water when the animal was alive.
52
Clues to Earth’s Past
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Fossils and
Ancient
Environments
Name
Date
Clues to Earth’s Past
Section 2 Relative Ages of Rocks
Scan the list below to preview Section 2 of your book.
• Read all section headings.
• Read all bold words.
• Look at all of the pictures.
• Think about what you already know about rock.
Write three facts you discovered about the relative ages of rocks as
you scanned the section. Accept all reasonable responses.
1. Some rocks are older than others.
2. In undisturbed layers, the oldest rock is on the bottom.
3. Most rock sequences are incomplete.
Review
Vocabulary Define sedimentary rock to show its scientific meaning.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
sedimentary rock
rock formed when sediments are compacted and cemented or
when minerals are precipitated from solution
New
Vocabulary Read each definition below. Write the correct vocabulary term in
principle of
superposition
relative age
unconformity
the blank to the left.
states that in undisturbed rock layers, the oldest rocks are on the
bottom and the rocks are progressively younger toward the top
age of something compared with the ages of other things
gap in a sequence of rock layers that is due to erosion or periods
without any deposition
Academic
Vocabulary Define sequence to show its scientific meaning.
sequence
one thing following another in a fixed order
Clues to Earth’s Past
53
Name
Date
Section 2 Relative Ages of Rocks
Superposition
I found this information
on page
.
Have partners demonstrate rock layers and
superposition with a
stack of magazines.
Relative Ages
I found this information
on page
.
(continued)
Model the principle of superposition by sketching a cross-section
of layers of undisturbed sedimentary rock. Number the layers,
starting with 1 for the oldest layer.
Sketches should depict horizontal layers.
Bottom layer should be numbered 1,
and others should be numbered in order
from bottom to top.
Describe how the relative age of a rock layer is different from the
actual age of the rock layer. Accept all reasonable responses.
When you know the relative age of a rock layer, you know only
layers. When you know the actual age of a layer of rock, you
know approximately how many years old the rock layer is.
I found this information
on page
.
Model how a folded rock formation containing limestone, coal,
and sandstone would form. Draw and label the layers as they
would form originally. Then draw what they would look like after
being folded.
Drawing should show
horizontal layers.
54
Clues to Earth’s Past
Drawing should show
the same layers folded.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
how old it is compared with other things, such as other rock
Name
Date
Section 2 Relative Ages of Rocks
Unconformities
I found this information
on page
.
(continued)
Compare and contrast angular unconformity, disconformity,
and nonconformity in rocks by sequencing the steps in their
formation.
Unconformities
Type
Angular
unconformity
How It Forms
1. Layers of sedimentary rock are tilted and
2. Exposed rock erodes.
uplifted.
3. Sedimentary layers are deposited on top.
Disconformity
1. Sedimentary rock is exposed.
2. Some rock layers erode.
3. Sedimentary layers are deposited on top.
Nonconformity 1. Igneous or metamorphic rocks are uplifted.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
2. Exposed rock erodes.
3. Sedimentary layers are deposited on top.
Matching Up
Rock Layers
Identify the two ways to match up, or correlate, exposed rock
layers from two different places. Complete the graphic organizer.
I found this information
on page
.
Match up
rock layers by
following the layer
across an area
using fossil evidence
that shows the same
types of fossils in
both places
S YNTHESIZE I T
As you pass through a highway cut, you notice distinct layers
of rock. Can you be sure that the top layer is the youngest one? Explain.
Accept all reasonable responses. No, the principle of superposition does not necessarily
apply because the layers may have been folded.
Clues to Earth’s Past
55
Name
Date
Clues to Earth’s Past
Section 3 Absolute Ages of Rocks
Predict three things that might be discussed in Section 3 as you
read the headings. Accept all reasonable responses.
1. what absolute age is
2. how radiometric dating is used to determine the age of rocks
3. who developed the idea of uniformitarianism
Review
Vocabulary Define isotopes to show its scientific meaning.
isotopes
atoms of the same element that have different numbers
New
Vocabulary Define these key terms to show their scientific meaning.
radioactive decay
process in which some isotopes break down into other isotopes
and particles
radiometric dating
process used to calculate the absolute age of rock by measuring
the ratio of parent isotope to daughter product in a mineral
uniformitarianism
principle stating that Earth processes occurring today are similar
to those that occurred in the past
Academic
Vocabulary Define ratio to show its scientific meaning.
ratio
56
Clues to Earth’s Past
relation of one thing to another in size or amount
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
of neutrons
Name
Date
Section 3 Absolute Ages of Rocks
Absolute Ages
and Radioactive
Decay
I found this information
on page
.
(continued)
Organize information about radioactive decay as a tool to find a
rock’s absolute age. Complete the Venn diagram below with at least
six points of information. Accept all reasonable responses.
Radioactive Decay
Alpha decay
Beta decay
Both
The nucleus
A neutron
Unstable
gives off
changes
isotopes break
an alpha
into a proton
down into other
particle.
by giving off
isotopes and particles.
an electron.
Each radioactive isotope
decays at a certain rate.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Rate of decay is measured
in half-lives.
The particle
The electron
Absolute
age
of
rock
can
contains
given off
be calculated by ratio
two neutrons
is called
of parent isotope to
and two
a beta
daughter product.
protons.
particle.
I found this information
on page
.
Create a bar chart to show four half-lives. Then draw a curve
connecting the tops of the bars. Label each axis.
Graphs should show
five bars: Parent
material–100%,
1 half life–50%,
2 half lives–25%,
3 half lives–12.5%,
and 4 half lives–6.25%.
1
2
3
4
5
Half-lives
Clues to Earth’s Past
57
Name
Date
Section 3 Absolute Ages of Rocks
(continued)
Radiometric Ages
Analyze carbon-14 dating by completing the statements.
I found this information
on page
.
The half-life of carbon-14 is
5,730 years
When carbon-14 decays, it becomes
nitrogen-14
.
bones
,
Carbon-14 radiometric dating is used for
wood
to
75,000 years
carbon-14 in the
charcoal
, and
.
samples up
old. Scientists compare amounts of
environment
to the amount in a fossil
of an organism that lived long ago. While the organism was alive,
it took in and processed carbon-14 and
approximate
Uniformitarianism
I found this information
on page
.
ratio
.
of carbon-14 to carbon-12 tells the
age
of the fossil.
Summarize Hutton’s view of uniformitarianism and the modern
view of changes that affect Earth.
Hutton’s view: Earth processes occurring today are similar to
those that occurred in the past.
Have groups of
students provide
examples of both
slow and fast change,
and describe how
those changes have
impacted Earth.
Modern view: Slow change occurs through everyday processes
over millions of years. Sudden, violent changes also occur, such
as a collision with a comet.
S YNTHESIZE I T
Explain why the principle of uniformitarianism is critical to
what you have learned about determining the absolute age of rocks.
The principle applies to the breakdown of isotopes at a regular rate. Radioactive decay
occurs at the same rate today that it did in the past. This regularity enables scientists to
measure changes and determine age.
58
Clues to Earth’s Past
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
The
carbon-12
Name
Date
Tie It Together
A paleontologist found the following composition of rock layers at a site. The
paleontologist concludes that no folding or other disruption has happened to
the layers. What can you conclude about the area’s history? Write a summary
of your conclusions.
Top layer: coal layer made up of altered plant material
Middle layer: mix of sandstone and shale, with some tracks made by dinosaurs
Bottom layer: limestone with fossils of clams, snails, and sea lilies
Accept all reasonable responses. At the earliest time shown by the rocks (represented
by the limestone layer), the area was under water. Organisms such as clams, snails,
and sea lilies lived in the water. Later, when the middle layer formed, the area was above
sea level. A river might have deposited the sand from which the sandstone formed.
Dinosaurs lived in the area. Later still, the area was a swamp with many lush plants,
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
which later formed coal.
Clues to Earth’s Past
59
Name
Date
Clues to Earth’s Past
Chapter Wrap-Up
Now that you have read the chapter, think about what you have learned and complete
the table below. Compare your previous answers with these.
1. Write an A if you agree with the statement.
2. Write a D if you disagree with the statement.
After You
Read
Clues to Earth’s Past
• The footprint of a dinosaur is considered
a fossil.
A
• Scientists use fossils to learn what an
environment was like long ago.
A
• The oldest rock layer is always the one
found on top.
D
• Scientists can determine the age of
some rocks.
A
Review
Review the information you included in your Foldable.
Study your Science Notebook on this chapter.
Study the definitions of vocabulary words.
Review daily homework assignments.
Re-read the chapter and review the charts, graphs, and illustrations.
Review the Self Check at the end of each section.
Look over the Chapter Review at the end of the chapter.
S UMMARIZE I T
Identify three facts about fossils and rock layers that you
found interesting. Accept all reasonable responses.
1. Fossils can form in many ways, including casts, molds, and carbon films. 2. Fossils
can be used to date rock layers. 3. Radioactive elements let scientists find the absolute
age of rock layers.
60
Clues to Earth’s Past
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Use this checklist to help you study.
Name
Date
Geologic Time
Before You Read
Preview the chapter title, section titles, and section headings. Complete the
first two columns of the table by listing at least two ideas for each section
in each column. Accept all reasonable responses.
K
What I know
W
What I want to find out
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Construct the Foldable as directed at the beginning of this chapter.
Science Journal
Describe how an animal or a plant might change if Earth becomes hotter in the next
million years.
Responses will vary. Animals and plants living far north will probably shift south.
Animals with limited mobility may become extinct. Accept responses that show
careful thought.
Geologic Time
61
Name
Date
Geologic Time
Section 1 Life and Geologic Time
Skim the headings in Section 1. Predict two topics that will be
covered in this section. Accept all reasonable responses.
1. the geologic time scale
2. natural selection
Review
Vocabulary Define fossils to show its scientific meaning.
fossils
remains, traces, or imprints of prehistoric organisms
New
Vocabulary Write the correct vocabulary term next to each definition.
representation of Earth’s history that shows the time units used
to divide it
eon
longest subdivision of geologic time
era
second-longest subdivision of geologic time
period
subdivision of an era
epoch
subdivision of a period
organic evolution
species
change of species through time
group of organisms that normally reproduce only with other
members of their group
natural selection
trilobite
process by which organisms that have characteristics that are
better suited to an environment have a better chance of surviving
and reproducing than those that do not
organism with a three-lobed exoskeleton that was abundant in
Paleozoic oceans
Pangaea
large ancient landmass composed of all the continents joined
together
Academic
Vocabulary Use a dictionary to define survive.
survive
62
Geologic Time
to continue to exist; to live through
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
geologic time scale
Name
Date
Section 1 Life and Geologic Time
Geologic Time
I found this information
on page
.
(continued)
Distinguish the units of geologic time. Give examples of each.
Accept all reasonable examples.
Largest subdivision: eon
Examples: Hadean, Archean, Proterozoic, Phanerozoic
Second-largest subdivision: era
Examples: Paleozoic, Mesozoic, Cenozoic
Encourage students
to work in pairs to
identify the major
subdivisions of
geologic time.
Third-largest subdivision: period
Examples: Cambrian, Ordovician, Triassic, Quaternary
Fourth-largest subdivision: epoch
Examples: Paleocene, Eocene, Oligocene, Miocene, Pliocene
Complete the table to identify when each of the following key
developments in the history of Earth occurred.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Event
Eon
Era
(if identified)
Period
(if identified)
First life
Archaean
N/A
N/A
First
trilobites
Phanerozoic
Paleozoic
Cambrian
First
flowering
plants
Phanerozoic
Mesozoic
Cretaceous
Organic Evolution
Sequence the steps of natural selection as described by Darwin.
I found this information
on page
.
1. Organisms show variation that may help or hurt their chances
of surviving in a changing environment.
2. Organisms that are well suited to their environment live longer
and have a better chance of reproducing.
3. Characteristics of organisms that are better suited to the
environment get passed on to offspring more often.
Geologic Time
63
Name
Date
Section 1 Life and Geologic Time
I found this information
on page
.
(continued)
Identify two factors that are necessary for natural selection to
occur within a species.
1. The trait must be present in some members of the species.
2. The trait must increase the organism’s chance of survival.
Trilobites
I found this information
on page
.
Organize information about how trilobites evolved over time.
Complete the flow charts.
Later trilobites
Early trilobites
became smaller
and disappeared
Eyes
most located midway
between front and
back of the head
became highly
complex; some were
compound or on stalks
Body
many segments in
middle part of body
Contrast two theories explaining the extinction of trilobites at the
end of the Paleozoic era. Fill in the missing words.
I found this information
on page
.
Some scientists believe that the formation of
caused
the amount of continental shelf to be reduced
.
survive in the changed conditions
.
Trilobites could not
Other scientists suggest that
other conditions
CONNECT IT
Pangaea
changes in climate or
caused the extinction.
Compare and contrast natural selection and artificial selection.
Accept all reasonable responses. In both natural and artificial selection, certain traits are
selectively passed to offspring. In artificial selection, a human decides which traits are
desirable. In natural selection, environmental pressures determine whether a trait is
beneficial to the organism.
64
Geologic Time
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Plate Tectonics
and Earth History
fewer segments
Name
Date
Geologic Time
Section 2 Early Earth History
Skim Section 2. Write three questions that come to mind from
looking at the headings and illustrations. Accept all reasonable
responses.
1. What was Precambrian time?
2. What types of organisms lived in the Paleozoic Era?
3. How are mountains formed?
Review
Vocabulary Define life to show its scientific meaning.
life
state of being in which one grows, reproduces, and maintains a
constant internal environment
New
Vocabulary Use your book to define each vocabulary term.
Precambrian time
longest part of Earth’s history, including the Hadean, Archean,
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
and Proterozoic Eons
cyanobacteria
blue-green algae thought to be one of the earliest forms of life
on Earth
Paleozoic Era
era of ancient life, which began about 544 million years ago and
ended about 248 million years ago
Academic
Vocabulary Use a dictionary to define hypothesis. Use hypothesis in a
sentence to show its scientific meaning.
hypothesis
a reasonable guess that can be tested and is based on what is
known and what is observed; Sample sentence: The scientist
made a hypothesis about why the Ediacaran organisms
disappeared.
Geologic Time
65
Name
Date
Section 2 Early Earth History
Precambrian
Time
I found this information
on page
.
(continued)
Summarize two reasons why little is known about the organisms
that lived during Precambrian time.
1. Many Precambrian rocks have been changed by heat and
pressure, which often destroys fossils.
2. Most organisms had soft bodies, which are less likely to be
preserved as fossils.
Encourage students
to work in pairs to
identify important
events during
Precambrian time.
Sequence important events in the evolution of life during
Precambrian time. Complete the flowchart.
cyanobacteria
The first
photosynthesis
appeared on Earth. They used
and produced
oxygen
Oxygen became a major gas in the atmosphere.
The first invertebrates appeared.
The Paleozoic Era
I found this information
on page
.
Organize information about life during the Paleozoic Era.
Complete the concept web with examples of life that appeared
during the Paleozoic Era.
trilobites
and other
invertebrates
reptiles
66
Geologic Time
.
Paleozoic
Life
trees
amphibians
fish
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
I found this information
on page
.
Name
Date
Section 2 Early Earth History
The Paleozoic Era
I found this information
on page
.
(continued)
Analyze how the characteristics of amphibians and reptiles allowed
them to live on land.
Amphibians
Characteristic
Effect
Lungs
allowed animals to live out of water
Legs
allowed animals to crawl and move
over land
Reptiles
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Characteristic
I found this information
on page
.
Effect
Protective coating
on eggs
allowed reptiles to lay eggs out of
water
Skin covered with
hard scales
prevented water loss; allowed reptiles
to live farther from water and in dry
climates
Organize information about three possible explanations of the
extinctions that took place at the end of the Paleozoic Era.
Possible Explanations
formation
of Pangaea
extensive
volcanic activity
collision with
an asteroid
S YNTHESIZE I T
Analyze SEE
why OVERSET
rock formations
PG that show the soft parts of
Paleozoic organisms are important.
The soft parts of organisms usually are not preserved. These rare fossils allow scientists
to learn more about early forms of life.
Geologic Time
67
Name
Date
Geologic Time
Section 3 Middle and Recent Earth History
Preview the What You’ll Learn statements for Section 3. Rewrite
each statement as a question. Look for the answers as you read.
1. What were characteristic life-forms
Accept all reasonable
responses.
in the Mesozoic and Cenozoic eras, and how did they differ?
2. How did changes caused by plate tectonics affect organisms
during the Mesozoic Era?
3. When did humans first appear on Earth?
Review
Vocabulary Define dinosaur to show its scientific meaning.
reptile from one of two orders that dominated the Mesozoic Era
New
Vocabulary Use your book to define each vocabulary term.
Mesozoic Era
era of middle life, during which many changes occurred
on Earth
Cenozoic Era
era of recent life, which began about 65 million years ago and
continues today
Academic
Vocabulary Use a dictionary to define diverse. Then use the term in an
original scientific sentence.
diverse
not all the same, varied; Sample sentence: Modern mammals
are diverse in the ways they meet their needs.
68
Geologic Time
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
dinosaur
Name
Date
Section 3 Middle and Recent Earth History
The Mesozoic Era
(continued)
Organize key information about dinosaurs.
I found this information
on page
.
Size
Activity
Some were less than
one meter tall; others
were very large.
Some were fast runners;
these may have been
warm-blooded.
Dinosaurs
Caring for Young
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Some species fed and
took care of young.
I found this information
on page
.
Complete the chart to identify key characteristics of other
important organisms from the Mesozoic Era.
Description
When They
Appeared
Birds
feathers; may have evolved
from meat-eating dinosaurs
Jurassic
Period
Mammals
small, mouselike, warm
blooded vertebrates with hair;
females produce milk to feed
young
Triassic
Period
Gymnosperms plants that produce seeds but
Angiosperms
not flowers
Paleozoic
Era
flowering plants that produce
seeds with hard outer coverings
Cretaceous
Period
Geologic Time
69
Name
Date
Section 3 Middle and Recent Earth History
The Mesozoic Era
I found this information
on page
.
(continued)
Summarize what happened at the end of the Mesozoic Era to the
environment and many species.
About 65 million years ago, most land and ocean species
became extinct. This included the dinosaurs. Many
paleontologists believe that this mass extinction was caused by
an asteroid colliding with Earth, creating a cloud of dust that
obscured sunlight.
The Cenozoic Era
Distinguish the two periods that make up the Cenozoic Era
I found this information
on page
.
1. Tertiary Period
, began about
65
million years ago
2. Quaternary Period , began about
1.8
million years ago
Grasslands
expanded.
Grazing mammals such as deer, horses,
and elephants grew larger.
Continents
moved apart.
Species became isolated
in Australia.
Homo sapiens
appeared.
Many other mammal species
became extinct.
S YNTHESIZE I T
Infer how paleontologists study the behaviors of extinct
animals, such as taking care of young. Accept all reasonable responses.
Paleontologists can study fossil evidence, such as Maiasaura fossils of adults and their
young in the same nests, and deduce their behavior from the fossils.
70
Geologic Time
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Analyze the effects of changes that occurred during the Cenozoic
Era. Complete the diagrams.
Name
Date
Tie It Together
You are directing a new movie about prehistoric times. The script you get shows
humans interacting with dinosaurs. Write a memo to the scriptwriter explaining
why this would not be scientifically accurate. Suggest two other possible settings,
one that includes dinosaurs and one that includes humans.
Memo:
Accept all reasonable responses. Students should indicate that dinosaurs were extinct
before large mammals, such as humans, evolved. Alternate settings should include
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
only organisms that existed at the same time as dinosaurs or humans.
Geologic Time
71
Name
Date
Geologic Time
Chapter Wrap-Up
After You Read
Review the ideas you listed in the chart at the beginning of the chapter. Cross out
any incorrect information in the first column. Then complete the chart by filling
in the third column.
K
What I know
W
What I want to find out
L
What I learned
Accept all reasonable
responses.
Use this checklist to help you study.
Review the information you included in your Foldable.
Study your Science Notebook on this chapter.
Study the definitions of vocabulary words.
Review daily homework assignments.
Re-read the chapter and review the charts, graphs, and illustrations.
Review the Self Check at the end of each section.
Look over the Chapter Review at the end of the chapter.
S UMMARIZE I T
After reading this chapter, identify three things that you have
learned about geologic time. Accept all reasonable responses.
1. A new characteristic becomes common in a species if the trait increases the organism’s
chance of survival. 2. Scientists divide geologic time into intervals based on fossil
evidence. 3. Little is known about Precambrian organisms because they left few fossils.
7 2
Geologic Time
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Review