the

Winter 2011

Investi-g

A science journal for elementary school students

United States

Department of

Agriculture

Forest

Service

International 

Year of Forests

2011

Pacific Northwest Research Station 

Climate Change Edition
2 The Investi-gator • http://www.scienceinvestigator.org 

Jessica Nickelsen, Co-Editor

Cradle of Forestry Interpretive Association

Babs McDonald, Co-Editor

U.S. Forest Service, Washington Office

Becky Bittner, Co-Editor

Conservation Education Coordinator, U.S. Forest Service, 

Pacific Northwest Research Station

Lynn Sullivan, Copy Editor

U.S. Forest Service Pacific Northwest Research Station

Nickola Dudley, Design/Layout

Asheville, NC

Forest Service scientists highlighted in the journal:

Keith Aubry, Pacific Northwest Research Station

Rick Edwards, Pacific Northwest Research Station

Kevin McKelvey, Rocky Mountain Research Station

Ron Neilson, Pacific Northwest Research Station

Deanna Olson, Pacific Northwest Research Station

Other scientists highlighted in this journal:

Jason Fellman, University of Alaska Southeast

Jóse Fragoso, Stanford University

Peter Hernes, University of California Davis

Eran Hood, University of Alaska Southeast

Terry Root, Stanford University

Durelle Scott, Virginia Tech

Rob Spencer, Woods Hole Research Center

Ken Thompson, University of Sheffield

The Investi-gator

Forest Service

Washington, DC

Tom Tidwell, Chief

Jimmy L. Reaves, Deputy Chief, Research and 

Development

Bov B. Eav, Director, Pacific Northwest Research Station 

Jim Hubbard, Deputy Chief, State and Private Forestry

Cindy Miner, Assistant Director for Communications, 

Pacific Northwest Research Station 

Frank Vanni, Publishing Director, Pacific Northwest 

Research Station

John Sebelius, Staff Director, Science Quality Services

Safiya Samman, Staff Director, Conservation Education

Cradle of Forestry Interpretive Association

Alex Comfort, Executive Director

Stuart Ryman, Chairman

Adam DeWitte, Director of Education

With thanks to

Rachel Small, Cradle of Forestry Interpretive Association

Michelle Andrews, University of Georgia

Emily Melear Daniels, Cradle of Forestry Interpretive 

Association

Pacific Northwest Research Station, Climate Change Edition Number 2 • Winter 2011

Published by the Pacific Northwest Research Station

Photo credits for cover: Brome McCreary (spring peeper), 

Ken Curtis (wolverine), Steve Baskauf (fruit), Durelle Scott (glacier).
Felida Elementary School, Vancouver, Washington, 

Mrs. Beaman’s 5th Grade Class

I love how you 

introduce the 

scientists.

Pictures 

should be in 

color.

I love all the 

cool things you are 

teaching.

It was 

really well written, 

loaded with useful 

facts! The pictures 

were also great! 

I would 

recommend to 

my friends.

 You 

[scientists] 

 do a lot of 

 wonderful things.

It is perfect 

for 5th graders.

I love your 

magazine and it 

teaches you a lot 

of things about 

the wild.

I really liked 

learning about carbon 

and how it is in every 

living thing.

I think no 

suggestions are 

needed as this article 

is excellent.

On the 

FACTivity, I liked 

how they used the 

word “explosive” instead 

of a boring or normal 

word (for the article 

“Seed Ya Later”).

The Investi-gator • http://www.scienceinvestigator.org 3

Editorial Review Board
4 The Investi-gator • http://www.scienceinvestigator.org 

Table of Contents

Editorial Review Board................................................................3

About the Investi-gator................................................................5

Who Are Scientists?.....................................................................6

Welcome to the Climate Change Investi-gator! ..........................7

Features

Amphibious Assault: 

How Climate Change May Affect Amphibian Breeding.................................... 9

Seed Ya Later!

Predicting the Movement of Trees in a Changing Climate...............................18

There’s Snow Place Like Home:

Tracking the Range of Wolverines Over Time.................................................28

Frozen Food: 

How Glaciers Provide Food for Animals That Live in the Ocean....................39

Investi-gator Photo Challenge ............................................................................................. 50 

Crossword Puzzle................................................................................................................. 52

Word Search......................................................................................................................... 53

Note to Educators................................................................................................................. 54

Lesson Plan .......................................................................................................................... 55

Reflection Section Answer Guide........................................................................................ 58

National Science Education Standards for the 

Pacific Northwest Edition of the Investi-gator .................................................................... 62

What Is the U.S. Forest Service? .................................................................Inside back cover

What Is the Pacific Northwest Research Station?........................................Inside back cover

What Is the Cradle of Forestry Interpretive Association? ...........................Inside back cover

The Investi-gator Review Board............................................................................ Back cover

Web Resources....................................................................................................... Back cover
The Investi-gator • http://www.scienceinvestigator.org 5

About the Investi-gator

Meet the Scientist

An introduction to the scientist or scientists 

who conducted the research.

Thinking About Science

A short introduction to something about the 

scientific process that is related to the research 

being presented.

Thinking About the Environment

A short introduction to something about the 

natural environment that is related to the 

research being presented.

Introduction

The part of the written scientific paper that 

introduces the scientific problem or question 

the scientists wants to solve or answer.

Method

The part of the written scientific paper that 

describes how the scientists collected and 

analyzed their data or information.

Each article is organized the same way and 

includes the following sections:

Findings

The part of the written scientific paper that 

describes what the scientists discovered.

Discussion

The part of the written scientific paper that 

summarizes the research and offers any new 

insights.

Reflection Sections

These are questions placed after the 

Introduction, Methods, Findings, and 

Discussion sections. The purpose of the 

questions is to help students think about what 

they have read.

Glossary

Possible new terms you will find in the article.

Glossary words are printed in bold in the 

article.

FACTivity

This is an activity that you can do in your 

classroom.

The Investi-gator is the newest member 

of the Natural Inquirer family. The Natural 

Inquirer, for middle school students, and 

the Investi-gator, for upper elementary level 

students, present science the way scientists 

most often share their research with each other. 

That process is the written scientific paper. 

Each Investi-gator article presents 

research conducted by Forest Service 

scientists and their cooperators. All of the 

research in the Investi-gator is concerned 

with nature or with society’s relationship 

to nature.
6 The Investi-gator • http://www.scienceinvestigator.org 

Scientists are people who collect and evaluate 

information about a wide range of topics. 

Some scientists study the natural environment.

To be a successful scientist, you must:

Who Are Scientists?

Be curious: 

You must be interested in learning.

Be enthusiastic:

You must be interested in a particular 

topic.

Question everything:

You must think about what you 

read and observe.

Be open-minded:

You must be willing to listen to 

new ideas.

Be careful:

You must be accurate in everything 

you do.
The Investi-gator • http://www.scienceinvestigator.org 7

Is the climate changing over time? In 

the past few years, most scientists have agreed 

on at least one thing about climate change. 

They have agreed that changes in Earth’s 

climate over the past 100 or more years point 

to a warming of Earth’s surface. This warming 

is greater than they would have expected from 

normal cycles. 

The average temperature of Earth depends 

on two things. First, the temperature depends 

on how much of the sun’s energy comes 

through the atmosphere to Earth’s surface. 

Second, the temperature depends on how 

much energy escapes back into space. About 

90 percent of the sun’s energy is trapped 

by gases in the atmosphere! This energy 

is sent back to Earth in all directions. This 

energy warms the planet. This is called the 

greenhouse effect. The gases are called 

greenhouse gases. Without these gases, 

humans and other forms of life could not 

survive on Earth. 

Over the last 150 years, however, the 

amount of greenhouse gases in the atmosphere 

has risen sharply. The sharp rise in greenhouse 

gases is believed to be caused by an increase 

in the burning 

of fossil fuels. 

Examples of 

fossil fuels are 

oil, coal, and 

natural gas. 

These higher 

levels of 

greenhouse 

gases in the 

atmosphere 

trap more of the sun’s heat. This 

leads to increasing temperatures on Earth.

Evidence from scientific measurements 

gives scientists more confidence in their 

conclusions about global climate change. 

Yearly global temperatures have been 

rising, the amount of Arctic sea ice has been 

shrinking, and glaciers are getting smaller. 

Scientists are now able to use computer 

programs for help. These computer 

programs track and predict changes in the 

atmosphere and oceans across the globe. 

Global climate change is sometimes 

called global warming. Scientists use the 

term “global climate change” because many 

aspects of Earth’s climate are changing. 

Along with rising yearly temperatures, 

scientists predict increases in both droughts 

and flooding. The effects of climate change 

will be different in different places on 

Earth. Some places will experience periods 

of heavy rain, for example, and others will 

experience periods of low rainfall.

Because of climate change, scientists 

and forest managers have had to think in 

new ways about our natural resources. While 

we work to reduce the amount of fossil fuels 

Welcome to the Climate Change Investi-gator!
8 The Investi-gator • http://www.scienceinvestigator.org 

how climate change may affect wolverines. 

Finally, in the article “Frozen Food,” you 

will learn how water from melting glaciers 

may provide food for animals living in 

nearby bays and rivers. Forest Service 

scientists have been a part of the research in 

these articles. You can learn more about the 

Forest Service by reading the inside back 

cover of this journal or by visiting 

http://www.scienceinvestigator.org. 

we burn, we also must work with the coming 

changes. Here are some of the new ways 

scientists and forest managers are thinking:

1. Instead of fighting change, work with 

it. Do what we can to reduce the impact 

of climate change, but be prepared for 

change and adapt as needed.

2. Understand that we do not know 

exactly what will happen in the future, 

but we do the best job we can with 

prediction. Sometimes, we will make a 

decision about what to do, and later we 

may have to make a different decision.

3. Accept that the way we did things in 

the past may not be the right choice for 

the future.

4. Focus on the way forests and other 

natural systems work, instead of what 

they look like. 

Climate change will bring challenges 

for everyone. However, climate change is 

also helping us to think in new ways and to 

do some things differently. In this Investigator, you will find research that focuses on 

the Pacific Northwest region of the United 

States. The scientists in this region have 

been studying how climate change may 

be affecting different animals, plants, and 

ecosystems. 

In this journal, you will read about four 

topics. In “Amphibious Assault” you will 

learn how frog and toad breeding patterns 

might respond to climate change. The article 

“Seed Ya Later!” examines how plants may 

move in a changing climate. In “There’s 

Snow Place Like Home” you will learn 

The Pacific Northwest region of the 

United States.

Washington

Oregon

Pacific

Ocean

Alaska
The Investi-gator • http://www.scienceinvestigator.org 9

Meet the Scientists!

What does the 

term “needle 

in a haystack” 

mean? What did 

Dr. Olson mean 

when she said 

that she found 

the needle in the 

haystack?

How Climate Change May Affect Amphibian Breeding

Dr. Root, ecologist: 

My favorite science experience was in 1995 

when I was at a meeting. A person speaking before 

me put up a graph that looked just like one of mine —

with years on the x-axis and day-of-arrival on the y-axis. 

The plot showed the tree was blooming earlier in the 

spring. My graph was for birds arriving earlier in the 

spring on migration. The other person’s study was in 

Europe and mine was in the US. Could it be that global 

warming was causing different types of species in 

different parts of the globe to change in 

similar manners? The answer was yes.

Dr. Olson,

research ecologist 

(ē köl ə jist): 

Finding my first breeding group of 

western toads in the Oregon Cascade 

Mountain Range is one of my all-time 

best moments. I had been hunting for 

toads for hours along a lake shoreline 

and was about ready to give up. Then, I 

realized I had been hearing a soft noise 

coming from out in the deeper water. 

I went closer and there were scores of 

breeding toads clustered in a very small 

area in some submerged shrubs. I later 

realized that I was incredibly 

lucky to have found the 

“needle in that haystack” 

that day!
10 The Investi-gator • http://www.scienceinvestigator.org 

Thinking About 

Science

Often scientists need 

to look at something over 

a period of time in order to 

understand what is really 

happening. The scientists in 

this study had information 

about frog breeding over many 

years. In some cases, they had 

information for 15 years in a 

row. 

When scientists are able to gather 

information over several years, it can give 

them a better idea of what is happening. For 

example, think about a year in school where 

you did not do your best work. Then you had 

several years where you did excellent work. 

You would want people to look at all your 

years of work rather than just the one year 

where your work was not as good. 

In the same way, scientists get a much 

clearer idea of what is happening when they 

have several years of information 

to review and study. In this study, 

the scientists were interested in 

climate change and amphibians. 

You will learn about both of these 

in the next section. 

Thinking About the 

Environment

Climate change influences 

many different things. 

Climate is the average 

condition of the 

weather (rainfall, temperatures, etc.) over 

large areas, over a long time, or both. When 

the climate changes, it affects animals and 

plants in different ways. Scientists believe 

that Earth’s climate is getting warmer. As 

the climate becomes warmer, scientists have 

found that the number of plants and animals 

changes. The places where these plants and 

animals live change too. The scientists in 

this study wanted to study the effect of a 

changing climate on one type of animal, the 

amphibians. 

Amphibians live part of their lives in 

the water and part of their lives on land. 

They are vertebrates or animals that have a 

backbone (figure 1). They are cold-blooded, 

which means their temperature depends on 

their environment. Some amphibians you 

might be familiar with are frogs and toads. 

What is another type of amphibian? 

Figure 1. Amphibians have a 

backbone and are cold-blooded.

Photo courtesy of Brome McCreary, US Geological Survey
The Investi-gator • http://www.scienceinvestigator.org 11

Introduction

Scientists have found that some plants 

and animals may be affected by a warmer 

climate. Butterflies, reptiles, birds, insects, 

and amphibians all seem to be affected by 

climate change. Climate change can change 

the breeding patterns of some animals. 

Breeding patterns refer to when and how 

animals reproduce, including how many 

young an animal has and how often. 

Scientists were particularly concerned 

about amphibians because some amphibian 

populations are declining. Amphibians 

may be more susceptible to climate change 

because they are cold-blooded animals. 

For a reminder of what cold-blooded 

means, reread the “Thinking About the 

Environment” section. 

If breeding patterns change, an entire 

population may change or become extinct. 

The question the scientists in this study 

wanted to answer was how certain amphibian 

populations and their breeding patterns may 

be responding to climate change.

Glossary

Amphibian (am fib ē ən): Animals that live 

part of their life in the water and part of their 

life on land. 

Breeding pattern (brē diŋ pat ərn): When 

and how animals reproduce, including how 

many young an animal has and how often.

Climate (klī mət): The average condition 

of the weather (rainfall, temperatures, etc.) 

over large areas, over a long time, or both.

Cold-blooded (kōld bləd ed): A 

characteristic of an animal whose body 

temperature depends on their environment.

Extinct (ek stiŋ(k)t): No longer living.

Vertebrate (vər tə brət): Animals that have 

a backbone.

Accented syllables are in bold.

Pronunciation Guide

ā as in ape

a as in car

ē as in me

i as in ice

ō as in go

oi as in for

Accented syllables are in bold.

ū as in use

u as in fur

ü as in tool

as in sing

as in about

(both a and u)

What is the problem the 

scientists wanted to answer in 

this study? 

Why might cold-blooded 

animals be more quickly 

affected by climate change 

than warm-blooded animals? 
12 The Investi-gator • http://www.scienceinvestigator.org 

Where Frog or toad 

studied

Scientific name 

of amphibian the 

scientist studied

Time period studied

Oregon Cascades frog

Western toad

Rana cascadae

Bufo boreas

1982–1999

Ontario Fowler’s toad Bufo fowleri 1980–1981, 1988–1998

Michigan Spring peeper Pseudacris crucifer 1967–1994 (not 1988)

Figure 3. Information about the frogs and toads that were studied.

Figure 4. Cascades frog.

Method

The scientists chose three places in 

North America where they had information 

available about amphibians over several 

years. They had information about 

amphibians in Oregon, Ontario, and 

Michigan (figure 2). They chose to study 

frogs and toads in these areas (figures 3–7). 

The scientists were interested in the 

effect of climate change on amphibian 

breeding. Therefore, the scientists had to 

find out certain information. They had to 

Figure 2. In this map of North 

America, you can see the location 

of the three areas scientists studied 

frogs and toads.

Figure 5. Western toad. 

Photo courtesy of Brome McCreary, US Geological Survey

Photo courtesy of Brome McCreary, US Geological Survey
The Investi-gator • http://www.scienceinvestigator.org 13

Figure 6. Spring peeper. 

Figure 7. Fowler’s toad. 

Figure 8a. Egg masses.

discover the first day of breeding season 

for each frog or toad over a period of years. 

For the Cascades frog and western toad, the 

scientists used the presence of egg masses 

as the first day of breeding (figures 8a and 

8b).

Some amphibians have a call that 

they make when they are ready to breed. 

For the spring peeper and Fowler’s toad, 

the scientists used the first date of calling 

as the beginning of breeding season. The 

Photo courtesy of Missouri Department of Conservation

Photo courtesy of J.D. Willson

Figure 8b. Egg masses.

Photo courtesy of Brome McCreary, US Geological Survey Photo courtesy of Brome McCreary, US Geological Survey
scientists also had to figure out the 

daily air temperature for the 3 months 

before breeding season. With all of this 

information, the scientists could figure 

out if climate change might have an 

effect on amphibian breeding patterns.

Frog or toad Breeding earlier?

Western toad Yes at one site, no 

at four other sites

Cascades frog No

Spring peeper No

Fowler’s toad No

Figure 9. Frog and toad breeding patterns.

Findings

The scientists found that one type of 

amphibian was breeding earlier (figure 9). 

The scientists found that other amphibians 

were not breeding earlier. 

Based on the scientists’ findings, 

does it look like climate change 

is having an effect on when the 

amphibians breed? 

Look at the findings for the 

western toad. Why do you think 

it is important to test at different 

sites? 

Look at the time periods studied 

in figure 3. What is one possible 

explanation for why the frogs 

and toads were not found to be 

breeding earlier?

Why do you think the scientists 

chose to study frogs and toads 

in three different areas? 

Why do you think the scientists 

wanted to know what the daily

air temperature was in the 3 

months before breeding season? 

14 The Investi-gator • http://www.scienceinvestigator.org 
The Investi-gator • http://www.scienceinvestigator.org 15

This article was adapted from Blaustein, A.R.; Belden, L.K.; Olson, 

D.H.; Green, D.M.; Root, T.L.; Kiesecker, J.M. 2001. Amphibian 

breeding and climate change. Conservation Biology. 15(6): 1804–1809.

Discussion

The breeding patterns did not show 

much change for several of the amphibians 

that the scientists studied. Scientists are not 

sure why the breeding patterns are changing 

for some but not for others. There are many 

reasons why amphibians may be sensitive 

to climate change. For example, amphibians 

are cold-blooded so they may be especially 

sensitive to changes in temperature. Changes 

in precipitation because of climate change 

could also affect the amphibians, but that 

was not the focus of this particular study. 

There have been other scientific studies 

that have shown that amphibians are being 

affected by climate change in various ways. 

However, based on the findings of the 

scientists in this study, the scientists think 

it is too early to say that climate change is 

affecting the timing of amphibian breeding 

in North America. 

The scientists believe that more studies 

need to be done over longer periods of time. 

These studies also need to be conducted 

Why would amphibians be 

particularly sensitive to changes 

in temperature? 

Do you agree with the scientists 

that more studies should be 

done? Why or why not?

Spring peeper—Spring peepers can allow most of their bodies to freeze during winter hibernation and still 

survive. http://animals.nationalgeographic.com/animals/amphibians/spring-peeper/

Western toad—Western toads are poisonous! They have enlarged glands (called parotid glands) behind each 

eye. These glands secrete a white poison that ends up inside the mouth of any predator who tries to munch a 

toad. http://www.blm.gov/id/st/en/prog/wildlife/amphibians/frogs_and_toads/western_toad_.html

Cascades frog—Cascades frogs have gold eyes and are named for their traditional homeland the Cascade 

Mountains. http://www.dfw.state.or.us/conservationstrategy/frogs.asp

Fowler’s toad—When handled roughly, Fowler’s toad feigns death and plays “possum.” It may lay on its 

back with legs curved upward and may remain motionless for several seconds until the threat has passed.

http://www.cmnh.org/site/ResearchandCollections/VertebrateZoology/Research/FamilyBufonidae/

FowlersToad.aspx

across more species and at more locations. 

After these additional studies, scientists 

can begin to draw conclusions about how 

climate change is affecting amphibian 

breeding patterns. Data gathered from this 

study will be good for comparisons of future 

breeding patterns.
16 The Investi-gator • http://www.scienceinvestigator.org 

Materials 

• Paper 

• Pencils 

• Crayons or 

markers for 

illustrations

Time needed: Three or four class periods 

The question 

you will answer in this 

FACTivity is: 

How are human life and 

frog life similar, and how 

are they different?

The process you will use to answer 

the question for this FACTivity is:

During the first class period (and 

perhaps into the second class period):

1. Students will break into pairs and 

write a story about a person who turns 

into a frog. 

2. Students will consider the following 

questions as they write. 

• What would the person do 

as a frog? 

• How would they survive? 

• What stages of the life cycle 

would they experience? 

• What would winter be like? 

3. Now reverse the situation and have 

a frog turn into a person. 

• What is life like now? 

• How might the human world be 

challenging for the frog person? 

• What would the frog person miss from 

its former life? 

• What would the frog person really 

enjoy?

In the third and fourth class period:

4. Once the students have written both stories, 

have them create a reversible booklet. On the 

right side of the booklet, students should write 

and illustrate their first story about a person 

turning into a frog. They should only use the 

right side of every page. Then they should flip 

the booklet over and write the other story going 

in the opposite direction. Don’t forget to add 

drawings.

5. Students can share their stories with 

classmates.

FACTivity
The Investi-gator • http://www.scienceinvestigator.org 17

Extension: If you have a kindergarten reading 

buddy or a younger class that your students read with, 

they can share their frog stories with them.

Here are some additional resources that you may use 

when completing this FACTivity.

The Frog Prince 

by the Brothers Grimm 

The Frog Prince Continued

by Jon Scieszka and Steve Johnson 

The Frog 

an Italian tale 

Frog and Toad Are Friends

by Arnold Lobel 

The Celebrated Jumping Frog of 

Calaveras County

by Mark Twain 

The Frog Who Became an Emperor 

a Chinese Fable 

Aesop’s Fables 

“The Frog and the Ox” 

“The Frogs and the Well” 

“The Frog’s Complaint Against the Sun” 

“The Frogs Asking for a King” 

“The Frogs Desiring a King”

Science as Inquiry: Abilities to do 

scientific inquiry, Understandings about 

scientific inquiry

Life Science: Reproduction and heredity, 

Regulation and behavior, Populations and 

ecosystems, Diversity and adaptation of 

organisms

Earth Science: Structure of the Earth 

system

Science in Personal and Social 

Perspectives: Natural hazards, Risks and 

benefits, Science and technology in society

Science and Technology: Understandings 

about science and technology

History and Nature of Science: Science as 

a human endeavor, Nature of science

Additional Web Resources

National Geographic’s spring peeper 

information

http://animals.nationalgeographic.com/

animals/amphibians/spring-peeper.html

Cascades frog habitat map

http://depts.washington.edu/natmap/maps/

wa/amphibians/WA_cascades_frog.html

Animal Diversity Web’s information 

on Fowler’s toad

http://animaldiversity.ummz.umich.edu/site/

accounts/information/Bufo_fowleri.html

USGS western toad information

http://www.npwrc.usgs.gov/resource/herps/

amphibid/species/bboreas.htm

National Science Education Standards 

addressed in this article:

If you are a trained Project WILD educator, you may 

use the activity “Stormy Weather” on page 85, asking 

students to visualize themselves as a frog or toad.

This activity is adapted from the Center for Global 

Environmental Education 

http://cgee.hamline.edu/frogs/teachers/activity/magic.html
18 The Investi-gator • http://www.scienceinvestigator.org 

Meet the Scientists!

Dr. Fragoso, ecologist (ē kə lō jist): 

As an ecologist, I study the relationships of 

living things with each other and with their environment. 

One of my favorite science experiences was flying my 

ultralight airplane over the Amazon rain forest. While 

flying, I learned to identify trees from the air. I also 

learned how the animals I radio-tracked 

moved over many miles from one 

patch of trees to another.

Predicting the Movement of Trees in 

a Changing Climate

Dr. Neilson

bioclimatologist 

(bī ō klī mə tə ō jist): 

I became a bioclimatologist because I like to 

be in the woods. Bioclimatologists study the relationship 

of living things to their climate. Climate is the average 

weather of an area over a long period of time. This can be 

months, years, or hundreds of years. As a young scientist, 

I began to compare different plants with their climate. I 

asked this question: How do different kinds of plants grow, 

reproduce, and die, while living where they do? After about 

15 years, I began to build models to better understand where 

plants live. Models are representations of something. In this 

case, my models were built on a computer. My models, unlike 

model cars or airplanes, were built from numbers. I compared 

different kinds of plants with the climate of their area. You 

will learn about these kinds of models in this article. 

By building computer models, I can better 

understand and predict what might happen to 

plants as their climate changes. It is great 

to be able to spend my time 

learning about the woods! 
The Investi-gator • http://www.scienceinvestigator.org 19

Thinking About 

Science

You probably hear a lot about 

scientific models. Scientists use 

models to examine how systems look 

and behave. In your school, you may 

have a model of the solar system. This 

model shows how the planets revolve 

around the sun. This is a model of 

the relationship of the planets to each 

other and to the sun. Scientists also use 

mathematics to create models. These 

models use numbers to represent real or 

possible relationships. 

In this research, the scientists 

wanted to improve their models. 

Their models showed where on Earth 

different kinds of trees might grow. 

As the climate changes, the places 

different trees can grow will change. 

The scientists were interested in how 

and where different types of trees 

might grow as the climate changes. 

They wanted the models to show how 

the seeds of trees move away from the 

parent tree. If they could include how 

seeds move, this would improve their 

models. They could do a better job of 

predicting where different types of trees 

might grow in the future.

Dr. Thompson,

plant ecologist: 

I’m very interested in the wildlife of gardens. 

My favorite project was one that showed just 

how much wildlife lives in a typical private 

garden. For me, however, the best moment in 

science is when you show that what 

everyone believes to be true 

is actually wrong!
Thinking About 

the Environment

How do trees move? 

You know that trees do not 

have legs and feet. A single 

tree cannot 

move to a 

new location. 

Trees use 

a different 

process to move. Trees move through 

their seeds. By having its seeds move 

away, a type of tree can move to a new 

location. 

Seeds move away from the parent 

tree in four ways. First, wind can blow 

the seeds away. Second, water can 

move the seeds downstream. 

Third, animals can carry seeds 

to new places. They do this when 

they eat seeds and later poop 

away from the tree. Animals can 

also carry seeds in their fur or 

they carry seeds in their mouth 

and drop them by mistake. Fourth, 

people can move seeds. Seeds, for 

example, can get stuck in car tires or 

on clothing.

Scientists have words to 

describe how far seeds move away 

from the parent tree. When a seed 

does not move far away from its parent 

tree, scientists say it has stepped from 

the tree. When a seed moves far away 

from its parent tree, scientists say it has 

jumped away from the tree.

Introduction

Scientists use models to predict what 

might happen in the future. Some scientists 

would like to predict the movement of 

trees as they respond to a changing climate. 

The scientists knew in what kind of areas 

different kinds of trees like to grow. They 

knew what temperatures different types of 

trees must have to grow (figures 1a, 1b, 

and 1c). The models needed improvement, 

however, because they did not include the 

different ways and rates that plants move. 

The scientists in this study wanted to answer 

this question: What is the best way to 

include the movement of tree seeds into their

models?

Figure 1a. Boreal (bör ē əl) 

trees grow in cold climates.

20 The Investi-gator • http://www.scienceinvestigator.org 
Figure 1c. Oak trees grow in both warm and 

cool climates.

The Investi-gator • http://www.scienceinvestigator.org 21

How does a tree move to a 

new location? 

Why do you think the scientists 

in this study wanted to include 

the movement of tree seeds 

into their models? (Hint: Reread 

the first two sentences in the 

“Introduction.”)

Figure 1b. Palm trees grow where it 

is warm all year. 
22 The Investi-gator • http://www.scienceinvestigator.org 

Figure 2. Seeds move 

from their parent tree in 

four main ways. 

Seed drops;

it has stepped 

from the tree. 

Seed is carried 

away by a bird 

and dropped; 

it has jumped 

from the tree. 

Figure 3. Seeds either “step” or “jump” away from their parent tree.

Method

The scientists identified what 

information they needed about 

how trees move. They collected 

information about how seeds move 

(figure 2). They learned not only 

how seeds move, but how far they 

can move (figure 3). The scientists 

also collected information about 

how trees grow in new areas 

(figure 4). They examined how this 

information could be included in 

their models. 

The scientists identified 

whether a seed was more likely to 

step or jump to a new area. They 

also considered how long it would 

take the different types of trees to 

grow in a new area. They put all of 

this information into one of their 

computer models.

Humans

Wind

Water

Animals
The Investi-gator • http://www.scienceinvestigator.org 23

Why is it important for the 

scientists to know how far and 

how fast seeds can move? 

Why was it important to know 

which tree seeds step and 

which ones jump? 

Figure 4. Seedlings need time to become established as healthy trees. Although 

these photos show different species of trees, you can see how a tree grows from 

a seedling (no. 1) to an established tree (no. 5). A tree can take 5 or more years to 

become established.

Photos courtesy of Babs McDonald, USDA Forest Service

1 2 3

4 5
24 The Investi-gator • http://www.scienceinvestigator.org 

As the climate warms, do you 

think different types of trees will 

be more likely to move north or 

south? Why? 

The scientists found that it was 

easier to predict the movement 

of trees with wind-blown seeds. 

Do you think it was also easier 

to predict the movement of 

trees whose seeds can float 

downstream? Why or Why not?

Figure 5. Winged seeds are most 

likely to move by being blown.

Figure 6. 

Animals may carry 

seeds away from their 

parent tree. How do 

you think this seed 

travels with an 

animal? 

Findings

The scientists placed different types of 

trees in categories by how their seeds were 

most likely to move. For example, maple, 

ash, and elm seeds have wings and are most 

likely to be blown by the wind (figure 5). Oak 

trees have acorns that would most likely be 

moved by squirrels and other animals (figure 

6). Birds may carry seeds and drop them by 

mistake. 

The scientists found that it was easier 

to predict the movement of some trees over 

others. Wind direction and speed are easier 

to predict than the movement of people and 

animals. The scientists found that they could 

better predict the movement of trees that have 

wind-blown seeds.

The scientists believe that the climate 

might change too fast for some trees to 

successfully move to new areas. As the 

climate changes, other types of trees will 

come in and take the old trees’ places. If the 

trees cannot successfully move to new areas, 

they might not survive.

Photo courtesy of Steve Baskauf, http://bioimages.vanderbilt.edu

Photo courtesy of Steve Baskauf, http://bioimages.vanderbilt.edu
Discussion

As the climate changes, the distance 

and speed of tree movement will affect how 

well a type of tree can survive. To better 

understand and predict the future, scientists 

need to include the movement of seeds in 

their models. Some types of trees will be 

able to move as the climate changes. Others 

will not be able to move successfully. If 

some trees cannot move successfully, other 

types of trees will likely take their place.

The Investi-gator • http://www.scienceinvestigator.org 25

If a type of tree is able to 

successfully move to a new 

location, what else might move 

with it? 

Could the types of trees growing 

near your home change over the 

next 100 years? Why or why not? 
26 The Investi-gator • http://www.scienceinvestigator.org 

The questions 

you will answer in 

this FACTivity are:

What are the different 

ways that seeds move?

How can models help 

us better understand 

how something 

happens?

Time needed: Two class periods 

(possibly more if you want students to 

create a model rather than draw one).

Materials 

• Six pieces of 

8 1⁄2 x 11 paper to 

make cards

• Pictures of fruit 

and seeds (p. 27)

• Blank paper for 

students to draw 

models

• Materials to create 

models (such as 

leaves, grass, twigs, 

art supplies, etc., 

optional)

FACTivity

Adapted from Neilson, R.P.; Pitelka, L.F.; Solomon, 

A.M.; Nathan, R.; Midgley, G.F.; Gragoso, J.M.V.; 

Lischke, H.; Thompson, K. 2005. Forecasting regional 

to global plant migration in response to climate change. 

BioScience. 55(9): 749–759. Discuss each of 

these briefly as you 

hold up each card. 

If you are a Project Learning Treetrained educator, you may use activity 

#43 “Have Seeds Will Travel” as an 

additional resource.

The method the class will use to 

answer this question is:

1. First, the teacher will introduce 

the different ways that seeds can 

move. An 8 1⁄2 x 11 card can be 

made with each of the following titles:

a. Wind

b. Water

c. Animals

d. Explosive (The fruit “explodes” 

sending the seed a small distance 

from the tree.)

e. Bounce or roll

f. Humans

2. In small groups, students will 

look at the figures accompanying this 

FACTivity. Students will discuss 

each picture and figure out how the 

seeds are moving. Each small group 

will make a list. After 5 minutes, each 

group will take a type of seed and tell 

the class how it moves away from 

its parent tree. For answers to this 

activity, please visit our Web site at 

www.scienceinvestigator.org and click 

on educator resources.

3. Once students have completed this 

part of the activity, they will draw or 

create a model of what it might look 

like as the seed moves. These models 

can be displayed in the classroom.
The Investi-gator • http://www.scienceinvestigator.org 27

All photos are by 

Bioimages www.bioimages.vanderbilt.edu

http://www.cas.vanderbilt.edu/bioimages/pages/fruit-seed-dispersal.htm

Figure 3.

Figure 5.

Figure 7.

Figure 4.

Figure 1.

Figure 2.

Figure 6. Figure 8.

Web Resources

Environmental Education for Kids—

Seedy Characters 

http://www.dnr.state.wi.us/org/caer/ce/eek/

cool/seedy.htm

University of Georgia Savannah River 

Ecology Lab’s Helicopter Seed Activity

http://www.uga.edu/srel/kidsdoscience/

kidsdoscience-copters.htm
28 The Investi-gator • http://www.scienceinvestigator.org 

There’s Snow Place 

Meet the Scientists!

Dr. Aubry,

research wildlife biologist:

One of my most interesting and 

exciting science experiences 

happened on the island of Tasmania 

(which is part of Australia). This was my 

first opportunity to experience the diversity 

of marsupials (pouched mammals) and egglaying mammals that occur in the Australian 

region. I saw and photographed a Tasmanian 

devil, ringtail and brushtail possums, Bennett’s 

wallaby (a small kangaroo), and a wombat. 

I learned all about the extinct Tasmanian tiger. 

One of my most memorable experiences was 

watching an echidna (one of only two egglaying mammals in the world) hunt for bugs. 

They look for bugs in decaying leaves and 

under rotting logs. The echidna looks 

like a slightly deflated soccer ball 

that is covered with 

poisonous spines!

Like Home: 
The Investi-gator • http://www.scienceinvestigator.org 29

Dr. McKelvey, 

wildlife ecologist: 

My favorite experience 

was digging out a wolverine 

snow-den in Glacier 

National Park. To study 

wolverines, scientists 

capture wolverine kits (baby 

wolverines). After the kits 

are captured, the scientists 

put tracking instruments on 

them. These instruments help 

us follow their movements. 

To put the instruments 

on them, we first dig down 

through the snow to the 

wolverine den site. The den 

site is usually under about 8 feet of snow and under large 

rocks or downed trees. To find the dens, we have to look for 

wolverine tracks. I was lucky enough to follow tracks that led 

to the den. The den was visible by a small hole in the snow. 

I was digging down, with the surface of the snow about 

2 feet above my head when I broke through into the center of 

the den. Immediately, I heard the wolverine mom growling 

right beneath my feet. I had this image of an angry female 

wolverine crawling up my leg and gnawing on my head. But 

Jeff Copeland, who has years of experience with wolverines 

(but who was also standing safely on top of the snow) said: “It 

will be fine.” It ended up being fine. 

We were able to capture the two kits, and conditions were 

perfect for putting the instruments on them without causing 

them a lot of stress. We had to work quickly with mom 

circling about 50 meters away, waiting for us to be done! 

(In the picture, the wolverine kit is covered with a blanket to 

protect its eyes while we are studying it. The wolverine kit 

was released back to its mother when we were finished.)
30 The Investi-gator • http://www.scienceinvestigator.org 

Thinking About 

Science

It is important for 

scientists to gather correct 

information about the 

topic they are studying. 

Not all information is 

reliable. Scientists need to 

be able to figure out whether 

the information they are 

collecting is reliable. In this 

study, scientists gathered information from 

several different places. 

They got information 

from museums, 

literature, and written 

material at state and 

federal buildings. The 

scientists did not use 

any information that 

was not reliable. When 

scientists (or you) 

use the Internet, care must be taken to 

know where the information came from. 

Usually, it is best to use Internet sites from 

the government (.gov), universities (.edu), or 

trusted sites like National Geographic. 

If the scientists did not feel confident 

about their information source, they did 

not use that information. Therefore, some 

information that may have been useful was 

lost. It is important for scientists to keep 

accurate and reliable information. If the 

information is accurate and reliable, then 

other scientists may use that information 

too. Your teacher probably asks you to 

carefully write down your observations and 

data during experiments at school. Now you 

can see why that is important! 

Thinking About the 

Environment

The Endangered Species Act is a law 

that was created in 1973. The law protects 

species that are in danger of becoming 

extinct. There are many reasons 

a plant or animal species may 

be placed on the list. For 

example, an animals’ habitat 

may be getting 

smaller. If an 

animal loses 

its habitat, 

it may not be 

able to live in another area. In this study, the 

scientists examined wolverine habitat. The 

scientists decided to study the wolverine’s 

range. The range is where the wolverines 

live across an area. The scientists wanted to 

know the range of the wolverines in the past 

and in the present.
The Investi-gator • http://www.scienceinvestigator.org 31

Introduction

Wolverines are the largest member of 

the weasel family that lives on land. They 

are mammals that are not easily found 

(figure 1). They live in areas far from 

humans and human development. Therefore, 

not much is known about these mammals. 

Wolverines are mostly scavengers. 

This means that they feed on dead 

animals. Sometimes wolverines travel 

great distances in a day in search of 

food or shelter. Wolverines may seek 

shelter under fallen logs or boulders. 

Female wolverines give birth to their 

kits in snow caves. Wolverines are 

currently found in most of Alaska 

and Canada and only in the northern 

portion of the Lower 48 States 

(figure 2). 

Figure 1. The wolverine is 

well-adapted for living in snowy 

environments. Look at the picture 

and name one adaptation the 

wolverine has to allow it to live 

in the snow. 

Figure 2. In the Lower 48 States, the wolverine’s 

current range (1995–2005) is found in the 

mountainous Northern States. The scientists 

studied wolverine habitat in these states. Do you 

live in any of the states or areas that were studied?

What do you know 

about these states 

that might make 

them good habitat for 

wolverines?
Before the scientists began their study, 

the range of wolverines was not well 

known. This was a problem. When some 

people asked for the wolverine to be listed 

as an Endangered Species their request was 

denied. One of the reasons the request was 

denied was because no one was certain 

where wolverines lived in the Lower 48 

States. The scientists in this study, therefore, 

wanted to accurately map the wolverine’s 

range over time. The scientists also wanted 

to study whether climate change is affecting 

the wolverines’ range.

32 The Investi-gator • http://www.scienceinvestigator.org 

Methods

By using a variety of sources, the 

scientists gathered records of wolverine 

sightings from 1801 through 2005. Each 

record included information identifying where 

the wolverines lived. The scientists divided 

the records into three periods. 

The periods were:

• 1995–2005 (current) 

• 1961–1994 (recent)

• 1801–1961 (historical)

The scientists used computer software 

to create maps with the data. The scientists 

collected information about climate over time. 

The scientists also gathered information about 

spring snow cover from recent years. This 

information was added to the maps. When 

this information was added to the maps, the 

scientists could see how climate and snow 

affected the wolverines’ range.

State in your own words and 

in the form of a question the 

problems the scientists were 

trying to study.

What are some other animals 

that burrow or make dens for 

their homes?
The Investi-gator • http://www.scienceinvestigator.org 33

Why do you think the scientists 

divided the years up into 

different periods?

How do you think warmer 

temperatures might affect 

wolverines? (Hint: Look back at the 

“Introduction” section to see where 

wolverines typically give birth.) 

Figure 3.

The historical 

distribution (A), recent 

distribution (B), and 

current distribution (C)

of wolverines in the 

Lower 48 States.

Findings

The completed maps show that 

the range of wolverines has shrunk, 

based on changes in the wolverine 

records from historical to current 

times (figure 3). It was also evident 

that wolverines depend on particular 

A.

B.

C.
34 The Investi-gator • http://www.scienceinvestigator.org 

habitat conditions for survival (figure 4). 

Wolverines were found in alpine meadows 

and conifer forests. Alpine meadows are 

found high in the mountains. They are 

above the tree line (figure 5). Conifer 

forests are areas with trees that have cones 

and typically do not lose their leaves in the 

fall or winter (figure 6). 

This study was the first time anyone 

accurately figured out the range of 

wolverines over time. This told the 

scientists several things. The scientists 

found that wolverines live in areas of the 

Lower 48 States where snowpacks stay 

through the spring. This is the time when 

wolverines make their dens. The scientists 

also found that most wolverines were 

found in alpine meadows and 

conifer forests. 

Figure 4. Wolverine distribution and 

the location of alpine areas and conifer 

forests. What do you notice about where 

the wolverines live?

Figure 5. Alpine areas have plants 

that are low to the ground so they can 

live in the cold temperatures. No trees 

can grow in these cold temperatures.

Photo courtesy of Babs McDonald, USDA Forest Service
Summarize what the scientists 

found in your own words. 

Do you think the findings support 

the idea that the wolverine’s 

habitat may be in danger? Why or 

why not?

The Investi-gator • http://www.scienceinvestigator.org 35

Figure 6. Many 

conifer trees grow 

in cooler climates. 

Photo courtesy of Babs McDonald, USDA Forest Service
36 The Investi-gator • http://www.scienceinvestigator.org 

This article was adapted from Aubry, K.B.; McKelvey, K.S.; Copeland, 

J.P. 2007. Distribution and broadscale habitat relations of the wolverine 

in the contiguous United States. Journal of Wildlife Management. 71(7): 

2147–2158. http://www.treesearch.fs.fed.us/pubs/28925

Glossary

Accurate (ak ür ət): Free from error. 

Echidna (ə kid nə): A type of egg-laying 

mammal that is also known as a spiny 

anteater.

Extinct (ek stin(k)t): No longer living.

Marsupial (mar sūp ē ul): A pouched 

mammal.

Habitat (hab uh tat): Environment where a 

plant or animal naturally grows and lives.

Observation (ob sür vā shun): Watching 

carefully and making note of details to help 

arrive at a judgment.

Reliable (re lī ə bəl): Dependable.

Species (spē sēz): Groups of organisms 

that resemble one another in appearance, 

behavior, chemical processes, and genetic 

structure.

Accented syllables are in bold.

Discussion

Wolverines have already lost areas 

where they can live. The finding that 

wolverines live near areas that have spring 

snow cover is important. It is important 

because if the climate changes and becomes 

warmer, areas that currently have spring 

snow cover may have snow melt earlier 

in the year. If the climate changes in these 

areas, the wolverine habitat will change too. 

Additionally, the wolverine’s reproduction 

may be affected. The scientists believe that 

more research needs to be done to fully 

understand what climate change means for 

wolverine populations.

Pronunciation Guide

ā as in ape

a as in car

ē as in me

i as in ice

ō as in go

oi as in for

Accented syllables are in bold.

ū as in use

u as in fur

ü as in tool

as in sing

as in about

(both a and u)

Why would the wolverine’s 

reproduction be affected?

(Hint: Think about why wolverines need 

spring snow cover.)

Based on what you have learned 

from this article, do you think it is 

possible that the wolverine may 

need to be listed as an endangered 

species at some point? 

Why or why not?
Time needed: Two class periods

• Animal field guides 

that include range 

maps, such as bird, 

reptile, amphibian, or 

mammal guides

• Two blank maps of 

the United States 

(see page 61)

• Two pieces of blank 

white 8 1⁄2 x 11 paper

• Markers

Materials needed per student group:

• What does your animal eat?

• Does your animal have predators? 

If so, what are they?

• What size is your animal?

• What does your animal look like?

• What is the climate where the 

animal lives?

• What are three adaptations 

your animal has so that it can live 

successfully in its habitat?

3. Use this information and any other 

interesting facts to create an Animal 

Fact File. The Animal Fact File should 

be displayed on two 8 1⁄2 by 11 pieces 

of paper. 

In the second class period:

1. One of the blank U.S. maps should 

be filled out with the current range 

where your animal is found. Label this 

map “Where [animal species name] 

Currently Lives.” The other map will 

be used to make a prediction about 

how you think your animal’s 

The process students will use to 

answer this question is:

In the first class period:

1. Choose an animal to study that 

lives in the United States. This animal 

may be selected from one of the field 

guides.

2. Using the field guide and other 

sources, find out the following 

information about your animal:

• What is your animal’s habitat? 

When you find out about the areas 

it lives in, mark those areas on one 

of the blank maps. 

The question 

students will answer 

in this FACTivity is: 

What is the geographic 

range of an animal? 

FACTivity

The Investi-gator • http://www.scienceinvestigator.org 37

u
Additional Web Resources:

National Geographic wolverine information 

and pictures

http://animals.nationalgeographic.com/

animals/mammals/wolverine.html

University of Michigan’s Animal Diversity 

Web—Wolverine information

http://animaldiversity.ummz.umich.edu/site/

accounts/information/Gulo_gulo.html

FACTivity continued

range will move as the climate 

becomes warmer. Think about what 

you read in the wolverine article to 

help you make this map. Label this 

map “Predicted Future Range of 

[animal species name].”

2. Once all of the groups have created 

an Animal Fact File and completed 

the two maps, the files and maps can 

be compiled into a class book. 

Extension: For students that need 

an extra challenge, they can include 

an Animal Fact File and map on 

one of the predators or prey for their 

animal. 

If you are a trained Project WILD 

educator, you may use the activity 

“Shrinking Habitat” on page 310.

National Science Education Standards 

addressed in this article:

38 The Investi-gator • http://www.scienceinvestigator.org 

Science as Inquiry: Abilities to do 

scientific inquiry, Understandings about 

scientific inquiry

Life Science: Reproduction and heredity, 

Regulation and behavior, Populations and 

ecosystems, Diversity and adaptation of 

organisms

Earth Science: Structure of the Earth 

system

Science in Personal and Social 

Perspectives: Natural hazards, Risks and 

benefits, Science and technology in society

Science and Technology: Understandings 

about science and technology

History and Nature of Science: Science 

as a human endeavor, Nature of science
Meet the

 Scientists!

The Investi-gator • http://www.scienceinvestigator.org 39

How Glaciers Provide Food for Animals 

That Live in the Ocean

Dr. Fellman,

My favorite science experience is going out to one 

biogeochemist: 

of my field sites and finding several chewed salmon 

carcasses and bear footprints as big as my head!

Dr. Hood, biogeochemist

(bī ō jē ō kə mist): 

My favorite science experience is 

being able to climb around 

on the glaciers in the Juneau 

(Alaska) Icefield as part 

of my research.

Dr. Spencer, 

biogeochemist: 

My favorite science 

experience was 

witnessing the spring 

thaw on the Yukon River 

in Alaska. This is called 

an “ice-out.” When the 

ice melts, it is like 

a river of ice. 

You can see it 

in the photo.
40 The 40 The Investi-gator • http://www.scienceinvestigator.org Investi-gator • http://www.scienceinvestigator.org 

Meet the Scientists! continued

Dr. Hernes,

aqueous organic geochemist 

(aw kwē us ôr gə nik jē ō kə mist): 

My favorite science experience 

is seeing our research published. 

When a research paper is published, 

I know that it will influence how 

other scientists think 

for years to come.

Dr. Edwards,

ecologist (ē käl ō jist): 

I’ve had so many wonderful experiences as 

a scientist I can’t pick a favorite. From seeing koalas 

(kō ow las) in trees in Australia, to watching a grizzly bear 

catch salmon in Alaska, my research has allowed me to see 

things I never thought I’d see. Aside from the beautiful 

places, I am happy to know that I have discovered 

things that no one knew before. This has 

given me the feeling that I have 

contributed something 

positive to people.

Dr. Scott,

biological systems engineer: 

One of my favorite science 

experiences was standing in the 

middle of a Rocky Mountain 

stream at 2 a.m. watching the 

Perseid (pər sē əd) meteor shower. 

The Perseid meteor shower 

occurs every August. 
The Investi-gator • http://www.scienceinvestigator.org 41

What is an aqueous 

organic geochemist?

This kind of scientist 

studies the impacts that 

organisms living in water 

(or ice) have on Earth.

Thinking About 

Science

Have you ever 

wondered how scientists 

can tell the age of 

something very old? 

Often they use the element 

carbon to help them. 

Carbon is present in all 

living and once-living 

things. There are three types 

of carbon in living things. 

They are called carbon 12, carbon 13, and 

carbon 14. Living things contain very little 

carbon 14. They contain a lot of carbon 12. 

The amount of carbon 14 compared to the 

amount of carbon 12 is the same in all living 

things. 

When living things die, the carbon 14 in 

them begins to decay. The carbon 12 does 

not decay. Scientists know exactly how fast 

carbon 14 decays. They can measure how 

much carbon 14 is present in something and 

compare that with how much carbon 12 is 

present. From this, they can estimate the 

object’s age up to about 50,000 years old.

What is an 

ecologist? This kind 

of scientist studies the 

relationships of living 

things with each other 

and with the nonliving 

environment.

What is a biogeochemist? 

This kind of scientist 

studies the movement of 

chemical elements, such 

as carbon and nitrogen. 

These scientists also study 

how chemical elements 

relate to and become a part 

of living things over time.

What Kind of 

Scientist?

What is a biological 

systems engineer?

This kind of scientist 

seeks to design and 

implement systems. These 

systems are meant to act 

like or use life processes 

for conservation and 

restoration of the natural 

environment.
42 The Investi-gator • http://www.scienceinvestigator.org 

Thinking About the 

Environment

Oceans cover most 

of Earth. They provide a 

home for many animals 

and plants. Rivers 

and bays close 

to the coast 

also provide 

a home for 

animals and 

plants. Rivers carry nutrients that were 

washed into the rivers and bays from the 

surrounding land. These nutrients become 

available to the animals living in the water. 

This also happens in areas where there are 

glaciers. As glaciers melt, whatever was 

frozen in or beneath them runs into coastal 

rivers and bays (figure 1). 

Introduction

From studies of rivers with forests along 

their banks, scientists know that some plant 

material gets washed into rivers and bays. 

Plant material, like all living things, contains 

carbon. The carbon is used by some animals 

living in the rivers and bays. These studies 

Figure 1. As this glacier melts, its 

freshwater goes into the bay.

Photo courtesy of Durelle Scott
The Investi-gator • http://www.scienceinvestigator.org 43

have found that as the carbon in the plant material ages, it is less useful 

to animals living in the water. 

In this study, the scientists studied glaciers and their nearby rivers 

in Alaska (figures 2 and 3). The water coming from glaciers can be 

quite old. This water might contain nutrients such as carbon. This 

carbon could be at least 5,000 years old. The scientists wondered about 

the glacier water running into coastal rivers and bays. They wondered 

if the carbon in the water was too old to be useful to animals living in 

the rivers and bays. 

State what the scientists wanted 

to study in the form of a question. 

Why did the scientists think the 

carbon might be too old to be 

useful to animals living in the 

rivers and bays? (Hint: Reread the 

last sentence in the first paragraph of the 

“Introduction.”) 

Figure 2. The 

areas studied by 

the scientists.

Figure 3. Glaciers sometimes 

look like huge rivers of ice. Photo courtesy of 

Durelle Scott
Figure 4.

Water was collected from rivers 

that contained melting 

glacier water.

Method

The scientists collected water from 11 

areas over 3 days in July 2008 (figure 4). 

All of the water came from rivers containing 

melting glacier water. These rivers were 

not affected by ocean tides. This helped the 

scientists to be sure that the water was not 

affected by salt water in the ocean. 

The scientists measured the amount of 

carbon in each container of collected water. 

They identified whether or not the carbon 

came from once-living plants or animals that 

are very old. They used carbon 14 dating to 

determine the age of the carbon. The pieces 

of material in the water were so small they 

could not be seen by the naked eye.

Why did the scientists avoid 

getting salt water in their 

samples? 

Think about the water coming 

out of the glaciers. Do you think 

the scientists found that the 

carbon was quite old? Why or 

why not?

44 The Investi-gator • http://www.scienceinvestigator.org 

Findings

The scientists knew that the glaciers 

covered ancient forests. The scientists 

found, however, that glacier water contained 

little material from ancient forests. They 

found that most of the glaciers’ carbon came 

from microbes. Microbes 

are too small to be seen 

by the naked eye. They 

include bacteria, 

fungi, and algae. 

Some kinds of 

bacteria can live in 

glaciers. The scientists 

believe that bacteria 

living in the glaciers 

have been eating old plant 

material for thousands of years. The old 

plant material came from the ancient forests. 

The carbon that is coming from glaciers 

today is made up of the remains of bacteria. Photo courtesy of Durelle Scott
The Investi-gator • http://www.scienceinvestigator.org 45

The scientists discovered that the larger 

the glacier was, the older the carbon was in 

the glacier water. The scientists also found 

something different than what scientists 

before them found. These scientists found 

that the older the carbon in the glacier water 

was, the more useful it was to animals living 

in the rivers and bays. In earlier studies, 

scientists found the opposite to be true.

Discussion

Glacier water is different than water 

flowing down rivers with forests along their 

banks. It is different in at least two ways. 

First, the carbon in the glacier water comes 

from microbes, not from grasses and trees. 

Second, the older the carbon in the glacier 

water is, the more useful it is to animals 

living in the rivers and bays. 

As the climate changes, the temperature 

will rise in the northern regions of Earth 

(figure 5). This will 

cause glaciers to melt 

faster. More carbon 

will be flowing into 

rivers and bays near the 

glaciers. Scientists do 

not know how this will change 

the ecosystem of the rivers and bays. They 

believe, however, that a greater amount 

of carbon will provide more nutrients to 

animals living in the rivers and bays. 

Are you surprised that the 

glacier water contained 

little material from ancient 

forests? Why or why not? 

What might happen to the 

flow of glacier water as the 

global climate changes? 

Figure 5. The northern region of Earth 

is shown lightly shaded in both images. 

On the right, you can see the North Pole in the 

center. The Arctic Circle is an invisible line of latitude 

on Earth's surface. Within the area north of the Arctic 

Circle, the sun never rises on the Winter Solstice 

(December 21) and it never sets on the Summer 

Solstice (June 21). The northern region of Earth includes 

an area south of the Arctic Circle, but there is no line that 

defines the exact area. Glaciers are found in Earth's northern 

region, including areas south of the Arctic Circle.
In the short term, more carbon and 

nitrogen might be helpful to animals living 

in the rivers and bays. In the long term, the 

scientists wonder what will happen after the 

glaciers have melted. There may no longer 

be very old carbon flowing into the rivers 

and bays.

Are you surprised that carbon 

that is thousands of years old 

is useful to animals living in 

nearby rivers and bays? Why 

or why not? 

As more glacier water runs 

into rivers and bays, will more 

or less nutrients be available 

to animals living there?

In the long term, what might 

happen to the food source 

coming from glaciers?

Glossary 

Algae (al jē): Simple, plantlike organism. 

Bacteria (bak tēr ē uh): A large group of 

one-celled organisms, too small to be seen by 

the naked eye. 

Carbon (kar bun): A chemical element 

present in all life forms. 

Ecosystem (ē kō sis tem): Community of 

plant and animal species interacting with one 

another and with the nonliving environment.

Freshwater (fresh wa tur): Having to do with 

or living in water that is not salty.

Fungi (fun jī): Organisms without 

chlorophyll that reproduce by spores. 

Mushrooms, molds, mildews, and toadstools 

are examples.

Nutrients ( nu trijənt): Any substance found 

in foods that are necessary for plants and 

animals.

Accented syllables are in bold.

This article was adapted from Hood, E.; Fellman, J.; Spencer, 

R.G.M.; Hernes, P.J.; Edwards, R.; D’Amore, D.; Scott, D. 

2009. Glaciers as a source of ancient and labile organic matter 

to the marine environment. Nature. 462: 1044–1047. 

46 The Investi-gator • http://www.scienceinvestigator.org 

Pronunciation Guide

ā as in ape

a as in car

ē as in me

i as in ice

ō as in go

oi as in for

Accented syllables are in bold.

ū as in use

u as in fur

ü as in tool

as in sing

as in about

(both a and u)
Time required: 30 to 40 minutes

Materials needed:

• One page of lined 

paper and pencil for 

each student. 

• A copy of page 

49 for each student. 

(Optional: An unlined 

piece of paper, 

scissors, and glue for 

each student.)

The question 

students will answer 

in this FACTivity is: 

What does photographic 

evidence appear to tell 

us about glaciers over 

the last century?

FACTivity

The process students will use to 

answer the question is as follows:

1. Students may work on page 49 in 

the journal, or may work from a sheet 

that was copied from this page. These 

are photographs of five glaciers in 

Alaska. The photographs on the left 

were taken in the early 1900s. The 

photographs on the right were taken in 

2000. 

2. Students will examine these 

photographs and do two main tasks.

• First, students will carefully observe 

the photographs and match the 

glacier photograph on the left with 

the glacier photograph on the right. 

Students may draw a line connecting 

the matching glacier photographs. 

If students are using a copy of the 

photographic sheet, they may cut the 

photos out and paste the pairs side-byside on a separate sheet of paper.

• Each student will select two pairs of 

matching photographs to observe.

3. Students will study each pair of 

photographs for 10 seconds. From 

this, students should form an overall 

impression of the photographs and 

write down their impression on a 

sheet of paper. In the next 4 minutes, 

students should compare and contrast 

the early photographs with the more 

recent photographs. To assist with the 

observation, students may divide each 

photo into quadrants (four equal areas) 

and study each section to see what new 

details become visible.

4. Based on these observations, 

students should list three things they 

might conclude from the two pairs of 

photographs.

The Investi-gator • http://www.scienceinvestigator.org 47
48 The Investi-gator • http://www.scienceinvestigator.org 

5. Hold a class discussion about the 

students’ observations. What was the 

students’ overall impression? What 

did students conclude about glaciers 

based on the photographs? 

6. Hold a class discussion about 

photographic evidence. Some 

questions to discuss are:

• Can photographic evidence be 

trusted? Why or why not?

• How do photographs provide 

information that words cannot?

• What might add to the photographic 

evidence presented by these 

photographs?

Now, answer the question posed at the 

beginning of this FACTivity.

Science as Inquiry: Abilities to do scientific 

inquiry, Understandings about scientific 

inquiry

Life Science: Reproduction and heredity, 

Regulation and behavior, Populations and 

ecosystems, Diversity and adaptation of 

organisms

Earth Science: Structure of the Earth system

Science in Personal and Social Perspectives:

Natural hazards, Risks and benefits, Science 

and technology in society

Science and Technology: Understandings 

about science and technology

History and Nature of Science: Science as a 

human endeavor, Nature of science

This FACTivity was adapted from 

http://www.windows2universe.org/teacher_resources/glacier_

then_now.pdf. The photographs were provided by the Glacier 

Photograph Collection. Boulder, Colorado USA: National Snow 

and Ice Data Center/World Data Center for Glaciology, http://

nsidc.org/

FACTivitycontinued

National Science Education 

Standards addressed in this article:

Web Site Resources

http://www.fs.fed.us/r10/tongass/forest_facts/

resources/geology/icefields.htm: Tongass 

National Forest, icefields and glaciers

http://www.pbs.org/wgbh/nova/vinson/glacier.

html: The life cycle of a glacier. 

This slide show traces the journey of a snowflake 

onto a glacier and eventually reaching the sea.

http://ga.water.usgs.gov/edu/earthglacier.

html: U.S. Geological Survey: glaciers and 

icecaps. Focuses on glaciers as a source of the 

world’s freshwater.

The research reported in this article was funded in part 

by the Hydrologic Sciences Program of the U.S. National 

Science Foundation.

If you are a Project WET-trained educator, 

you may use the activity “Old Water,” page 

171, as a supplemental activity.
The Investi-gator • http://www.scienceinvestigator.org 49

2000. Photo by Bruce F. Molina

2004. Photo by Bruce F. Molina

2004. Photo by Bruce F. Molina

Muir Glacier 1941. Photograph by William O. Field

Toboggan Glacier 1909. Photo by Sidney Page

Pedersen Glacier 1909. Photo by Ulysses Sherman Grant 2004. Photograph courtesy of the U.S. Geological Survey

McCarty Glacier 1909. Photograph by Ulysses Sherman Grant

Holgate Glacier 1909. Photograph by Ulysses Sherman Grant

2004. Photograph by Bruce F. Molina
50 The Investi-gator • http://www.scienceinvestigator.org 

Pick one of the following pictures 

and see if you can remember 

which article contained the 

photo and why. Write two 

to three sentences explaining 

how you know which article 

contained the photo.

Investi-gator

PhotoChallenge

See how many you can get right!
The Investi-gator • http://www.scienceinvestigator.org 51
52 The Investi-gator • http://www.scienceinvestigator.org 
The Investi-gator • http://www.scienceinvestigator.org 53
54 The Investi-gator • http://www.scienceinvestigator.org 

Note to Educators

Science education is increasingly in the spotlight as 

society recognizes the importance of scientific literacy to the 

Nation’s future. As teachers of science, you are being asked 

to prepare your students by providing both breadth and depth 

in science topics and process. The Investi-gator is a resource 

to help you teach both scientific content and process to your 

students. The Investi-gator integrates science with a number 

of disciplines, including language arts, geography, math, and 

social studies. Therefore, the Investi-gator can be used for 

team teaching or simply to reinforce the interdependent nature 

of learning and knowledge to your students. 

You understand the importance of hands-on learning. 

Although hands-on experience is a critical component of 

student scientific learning, science education standards have 

increasingly also highlighted the role of minds-on learning. 

True scientific literacy occurs when students can critically 

think about scientific questions, processes, and findings, as 

well as participate in data collection, observation, and analysis. 

You can use the Investi-gator to introduce science as a process 

that integrates minds-on learning with hands-on learning. 

At the end of each article, an easy-to-do activity, called a 

FACTivity, is provided to highlight a topic or process concept 

from the article. A reference to appropriate Project Learning 

Tree (PLT), Project WET, and Project WILD activities is also 

provided for those educators certified in those programs. For 

more information about these programs, visit http://www. plt.

org, www.projectwet.org, or www.projectwild.org. 

How to Use This Journal in Your Classroom

The Investi-gator is written at the fifth-grade level. Each 

article is written from an actual published scientific paper 

presenting contemporary environmental research. At the back 

of this journal, you will find two resources to help you use 

the journal more effectively. A matrix is given that indicates 

which national science education standards can be addressed 

by each article. A lesson plan is also provided that can be used 

with all four of the articles. The lesson plan helps you apply 

a reading strategy that will increase student comprehension. 

Along with the FACTivity, the lesson plan will help you 

integrate minds-on and hands-on scientific learning.

Help Us Improve the Investi-gator

Visit http://www.naturalinquirer.org to find student and 

teacher evaluation forms. These forms give you an opportunity 

to provide feedback that will help us improve the journal. 

Please take a moment to complete the evaluation form and if 

possible, invite your students to evaluate the journal as well. 

By completing the evaluation form, your students can learn 

the importance of providing assessment, much as you do when 

you assess their achievement. You may also make comments 

via the Web site. For more information, to ask questions, or to 

provide comment, contact:

The Investi-gator is a member of the Natural Inquirer family. The Natural Inquirer is a science 

education journal for middle school students. To explore more resources for using these journals, visit 

the Natural Inquirer Web site at http://www.naturalinquirer.org

Visit the Investi-gator Web site at http://www.scienceinvestigator.org

Dr. Barbara (Babs) McDonald

Forest Service

320 Green St.

Athens, GA 30602-2044

706.559.4224

bmcdonald@fs.fed.us

(Please put “Educator Feedback” in the subject line)
The Investi-gator • http://www.scienceinvestigator.org 55

Lesson

Science Skills: Communication, Inquiry 

National Science Education Standards:

Abilities to do scientific inquiry, Understandings 

about science inquiry, Science as a human 

endeavor

Note: This is a generic lesson plan that can be used 

with any Investi-gator or Natural Inquirer article.

Estimated Time

One and one-half class periods (plus an optional third 

period for the FACTivity)

Materials

• Investi-gator 2nd edition (one per student)

• 1 unlined piece of paper per student

• 1 lined piece of paper per student

• Pencils

Procedure

Day 1: 10-15 minutes

Introduce the scientific process, as expressed in 

scientific writing, to your students. Explain that 

scientists communicate with each other in writing by 

completing a scientific paper. A scientific paper is 

similar to what they do when they write a research 

paper. A scientific paper may have a number of 

sections, but they usually include:

1. Introduction section. The introduction gives 

the background of the research problem. It 

explains what the problem is and why it is a 

problem. It usually ends with a statement of 

the question the scientist wanted to answer or 

the specific problem to be solved.

Plan

2. Methods section. The methods section 

explains what kind of data or information 

the scientist collected, how it was 

collected, and how it was analyzed.

3. Findings section. The findings section 

presents the results of the data analysis 

and usually includes an interpretation 

of the analysis. An interpretation of the 

analysis is different than the analysis 

itself. The analysis is a process of data or 

information reduction, and may include 

mathematical and statistical processes. 

Mathematical and statistical analyses are 

not mandatory, as many forms of analysis 

may include non-numerical processes. 

The interpretation is the meaning given 

to the analysis. Different scientists 

could even interpret the same data or 

information in different ways.

4. Discussion (or implications) section.

In this section, the scientist usually 

discusses the findings and interpretation 

in light of the original problem presented 

in the Introduction section. In addition, this 

section often suggests new questions or 

problems to be answered or solved.

Explain to your students that there are many 

ways to solve scientific problems or answer 

scientific questions. The type of data or 

information collected and the way it is analyzed 

depends on the problem or question. Introduce 

the Investi-gator by telling them that they will 

be reading a scientific paper written at their 

grade level. Tell them that this paper is based 

on an actual scientific paper written by scientists 

working for the U.S. Forest Service, a United 

States government agency.
56 The Investi-gator • http://www.scienceinvestigator.org 

1. Briefly introduce the article you have chosen, 

emphasizing the topic and the particular 

research question being addressed in the 

article. Give students two pieces of paper 

each. Have the students label the unlined 

sheet of paper with K-W-L and draw three 

columns—Column 1 K (What do you Know?), 

Column 2 W (What do you think you will 

learn?), Column 3 L (What did you Learn?). 

Label the lined sheet of paper “Reflection 

Questions.” Have student divide the sheet 

of paper in four sections. Label the sections 

“Introduction,” “Method,” “Findings,” and 

“Discussion.”

2. Place students into groups of 3 to 5. Have 

students fill in the “K” column with words, 

terms, or phrases from their background or 

prior knowledge regarding the topic of the 

article. If you are having them draw on a topic 

previously learned, then the K column may 

be topic-related. But if the topic is something 

brand new, and they don’t know anything (or 

much) about it, you should use the K column 

to have them bring to mind a similar, analogous, or broader idea. 

3. Hand each student an Investi-gator. Have 

students predict what they might learn 

about the topic. (Complete the “W” column.) 

Students may look through the article to 

glance at headings, pictures, and charts. 

This technique helps focus their attention on 

key ideas. Students may add ideas about 

what they want to learn about the topic in the 

middle column too.

4. For homework, ask students to read the 

article that you have chosen. Students 

should read the entire article, but they do not 

need to read the FACTivity or the Reflection 

Questions.

Day 2: Entire class period

Within each group, have students read the article 

aloud. Have students alternate reading paragraphs. At the end of each section have students 

discuss and answer the reflection questions on the 

piece of paper labeled “Reflection Questions.” 

After reading, students should fill in their new 

knowledge gained from reading the content. The 

student’s misconceptions about the topic from the 

Know column before reading the article may be addressed from the knowledge gained from actually 

reading the article. Hold a class discussion about 

misconceptions, predictions, and new knowledge. 

Use these questions to get you started:

1. What misconceptions did you have? Where 

did those misconceptions come from?

2. What clues did you use to predict what you 

might learn from the article? Were your 

predictions accurate? Why or why not?

3. What did you learn from the article that 

cleared up a misconception? 

If you have time or as an extension,

1. Have each group designate a presenter. The 

presenter will present a reflection section answer 

and rationale to the class. Have the student read 

the reflection question before giving the answer 

and rationale. Continue with all groups until all 

Reflection Questions have been presented.

2. If time allows, hold a class discussion about 

the article. What did the students learn? What did 

they like or dislike about the article? Challenge the 

students to discuss how the research they just read 

might affect them personally. How might it affect 

their community?
The Investi-gator • http://www.scienceinvestigator.org 57

For each 

column 

(K, W, L)

No attempt to 

answer

1 to 2 items 

identified

3 to 4 items 

identified

5 or more items 

identified

SCORE 0 1 2 3

Assessment scoring: 

Total Score 0 = 0 points

Total Score 1–2 = 1 point

Total Score 3–4 = 2 points

Total Score 5–6 = 3 points

Total Score 7–8 = 4 points

Total Score 9 = 5 points

Assessment Rubric

Day 3: Continue with the FACTivity if needed.

Assessment

Collect the students’ K-W-L sheets and reflection 

question sheets. You can assess students 

comprehension from the responses found on the 

sheet.
58 The Investi-gator • http://www.scienceinvestigator.org 

Reflection Section Answer Guide

Note to Educator: The purpose of the Reflection section 

questions is to encourage students to think critically 

about what they have read. The following “answers” are 

only suggestions to assist you in using these questions in 

the classroom.

Amphibious Assault: How Climate Change 

May Affect Amphibian Breeding

Introduction

What is the problem the scientists wanted to answer in 

this study? Scientists wanted to find out how amphibian 

breeding may be affected by climate change.

Why might cold-blooded animals be more quickly 

affected by climate change? Cold-blooded animals 

may be affected more quickly by climate change 

because their body temperature and activities depend 

on the environment. Therefore, if the temperature of 

the environment changes, so do the temperature and 

activities of the cold-blooded animal.

Method

Why do you think scientists chose to study frogs and 

toads in three different areas? Scientists often choose to 

gather their data from more than one location because 

it helps the scientists make sure that their findings are 

reliable. Also scientists may want to compare similarities 

and differences across different areas and species.

Why do you think scientists wanted to know what 

the daily air temperature was in the 3 months before 

breeding season? To have a good understanding of 

the changing temperature and how that may affect 

amphibian breeding, the scientists needed to have 

several months of data on the air temperature. This way, 

the scientists could see how the temperature changed 

over that period and how that change may have affected 

the amphibians.

Findings

Based on the scientists’ findings, does it look like climate 

change is having an effect on when the amphibians 

breed? Based on the scientists’ findings, it does not look 

like climate change is having a significant effect on 

amphibian breeding, up to the time of the study (year 

2000) and for most of the species and sites surveyed in 

this study.

Look at the findings for the western toad. Why do 

you think it is important to test at different sites? It is 

important to test at different sites because if the scientists 

had only tested two sites, they may not have seen a 

change at one site. Instead, they may have concluded 

that there were no changes at all. 

Look at the periods studied in figure 3. What is one 

possible reason the scientists found that frogs and toads 

were not breeding earlier? The periods may not have 

been long enough to show enough of a change in the 

temperature. If the scientists had studied frog and toad 

breeding over the past 50 years, for example, they may 

have had different results. 

Discussion

Why would amphibians be particularly sensitive 

to changes in temperature? Amphibians are coldblooded, which means they are sensitive to changes in 

temperature. 

Do you agree with the scientists that more studies 

should be done? Why or why not? This is an individual 

question. Students should be able to support their 

answers with sound logic and reasoning.

Seed Ya Later! Predicting the Movement of 

Trees in a Changing Climate

Introduction

How does a tree move to a new location? Tree species 

move to new locations through the movement of their 

seeds.

Why do you think the scientists in this study wanted 

to include the movement of tree seeds into their 

models? (Hint: Reread the first two sentences in the 

“Introduction.”) The rate at which tree species can 

move in a changing climate is related to the method and 

distance of seed dispersal. If the scientists could include 

this information in their models, they can make more 

accurate predictions of what might happen in a changing 

climate.
The Investi-gator • http://www.scienceinvestigator.org 59

Method

Why is it important for the scientists to know how far 

and how fast seeds can move? Trees move somewhat 

slowly as a species. The climate is changing, and 

therefore the scientists must be able to compare the rate 

of climate change with the rate of movement for different 

tree species.

Why was it important to know which tree seeds step and 

which ones can jump? Jumping seeds can travel longer 

distances and therefore may enable some tree species to 

move faster, over time, than other species. These species 

may be more successful at becoming established in new 

areas as the climate changes.

Findings

As the climate warms, do you think different types of 

trees will be more likely to move north or south? Why? 

Students should be able to reason that tree species will 

be more likely to move north, as a favorable climate will 

move farther north.

The scientists found that it was easier to predict the 

movement of trees with wind-blown seeds. Do you 

think it was also easier to predict the movement of trees 

whose seeds can float downstream? Why or why not? 

Students should realize that it is easier to predict the 

movement of plants and trees whose seeds can float, as 

the direction and speed of streams and rivers can be 

easily determined.

Discussion

If a type of tree is able to successfully move to a new 

location, what else might move with it? Animals that use 

the type of tree for habitat and as a food source would 

likely move as the trees move. This includes mammals, 

birds, and insects.

Could the types of trees growing near your home change 

over the next 100 years? Why or why not? Students 

should reason this for themselves, but should conclude 

that as the climate changes over the next 100 years, the 

types of trees growing near their home may change as 

well.

There’s Snow Place Like Home: Tracking the 

Range of Wolverines Over Time

Introduction

State in your own words and in the form of a question, 

the problems the scientists were trying to study. What 

is the geographic range of wolverines over time? How 

could climate change affect the geographic range of 

wolverines?

What are some other animals that burrow or make dens 

for their homes? There are many different animals 

that burrow or make dens. Some examples include 

groundhogs, ants, hamsters, foxes, ferrets, chipmunks, 

badgers, moles, prairie dogs, pikas, rabbits, shrews, and 

sand dollars.

Method

Why do you think the scientists divided the years up 

into different time periods? The scientists divided the 

time because it was easier to discuss and compare their 

findings based on three smaller periods.

How do you think warmer temperatures might affect 

wolverines? (Hint: Look back at the “Introduction” 

section to see where wolverines typically give birth.) 

Warmer temperatures may cause the snow to melt 

earlier. If the snow melts earlier, the wolverine’s denning 

habitat won’t be as good. 

Findings

Summarize what the scientists found in your own words. 

The scientists found that spring snow cover, alpine areas, 

and conifer forests were important to the geographic 

range of wolverines. They also found that by the 1950s, 

wolverine range had shrunk. 

Do you think the findings support the idea that the 

wolverine’s habitat may be in danger? Why or why not? 

This is an individual question. Students should be able to 

support their answers with examples from the article.
60 The Investi-gator • http://www.scienceinvestigator.org 

Discussion

Why would the wolverine’s reproduction be affected? 

(Hint: Think about why wolverines need spring snow 

cover.) The wolverines make their dens in the snow. They 

reproduce and raise their kits in these dens. 

Based on what you have learned from this article, do you 

think it is possible that the wolverine may need to be 

listed as an endangered species at some point? Why or 

why not? This is an individual question. Students should 

be able to support their answers with examples from the 

article. 

Frozen Food: How Glaciers Provide Food for 

Animals That Live in the Ocean

Introduction

State what the scientists wanted to study in the form of 

a question. Is the carbon in glacier water too old to be 

useful to animals living in nearby rivers and bays?

Why did the scientists think the carbon might be too 

old to be useful to animals living in the rivers and bays? 

(Hint: Reread the last sentence in the first paragraph of 

the “Introduction.”) Earlier studies of rivers with forests 

along their banks had shown that as carbon in plant 

material in the rivers gets older, it is less useful to the 

animals living in the rivers and bays. If the same thing 

were true of glaciers, the ancient carbon and nutrients 

would not be very useful to the animals.

Method

Why did the scientists avoid getting salt water in their 

samples? The scientists were studying freshwater 

coming from glacial rivers. If they got salt water in their 

samples, they would not be testing the glacier water.

Think about the water coming out of the glaciers. Do 

you think the scientists found that the carbon was quite 

old? Why or why not? Students should reason that 

because glaciers are quite old, the material being held in 

their ice is quite old as well. Regardless, students should 

be able to back up their answer with logic. 

Findings

Are you surprised that the glacier water contained little 

material from ancient forests? Why or why not? This is 

an individual question and students should back up their 

answer with logic.

What might happen to the flow of glacier water as the 

global climate changes? Students should realize that the 

glaciers will melt faster, causing more water to flow into 

rivers and bays.

Discussion

Are you surprised that carbon that is thousands of years 

old is useful to animals living in nearby rivers and bays? 

Why or why not? This is an individual question, however 

based on studies of rivers with forested banks, students 

should be surprised that the situation is different in 

glacial waters.

As more glacier water runs into rivers and bays, will 

more or less nutrients be available to animals living 

there? Students should realize that more nutrients will 

be available to animals living in rivers and bays near 

glaciers. This is true in the short term. However in the 

long term, especially after the glaciers have almost 

completely melted, fewer nutrients will be available.

In the long term, what might happen to the food source 

coming from glaciers? Students should reason that after 

the glaciers have melted, the carbon that is used as a 

food source will no longer be available to animals living 

in the rivers and bays.
The Investi-gator • http://www.scienceinvestigator.org 61
62 The Investi-gator • http://www.scienceinvestigator.org 

Journal Article Amphibious 

Assault

Seed Ya Later! Snow Place 

Like Home

Frozen Food

Science as Inquiry

Abilities Necessary to Do Scientific 

Inquiry

Understanding About Scientific Inquiry

Life Science

Structure and Function in Living Systems

Regulation and Behavior

Populations and Ecosystems

Diversity and Adaptations of Organisms

Earth Science

Structure of Earth System

Science in Personal and Social 

Perspectives

Natural Hazards

Risks and Benefits

Science and Technology in Society

Science and Technology

Understanding About Science and 

Technology

History and Nature of Science

Science as a Human Endeavor

Nature of Science

National Science Education Standards for the Pacific Northwest 

Edition of the Investi-gator
The Investi-gator • http://www.scienceinvestigator.org 63

What Is the U.S. Forest Service?

The Forest Service is a part of the United States Department of Agriculture (USDA). It is made up of thousands of 

people who care for the Nation’s forest land. The USDA Forest Service manages over 150 national forests and almost 

20 national grasslands. These are large areas of trees, streams, and grasslands. National forests are similar in some ways 

to national parks. Both are public lands, meaning that they are owned by the public and managed for the public’s use 

and benefit. Both national forests and national parks provide clean water, homes for the animals that live in the wild, and 

places for people to do fun things in the outdoors. National forests also provide resources for people to use, such as trees 

for lumber, minerals, and plants used for medicines. Some people in the USDA Forest Service are scientists, whose 

work is presented in the journal. USDA Forest Service scientists work to solve problems and provide new information 

about natural resources so that we can make sure our natural environment is healthy, now and into the future.

For more information, visit http://www.fs.fed.us.

What Is the Pacific Northwest 

Research Station?

The Pacific Northwest Research Station provides 

scientific information to land managers, policymakers, 

and citizens. The station has 11 locations in Alaska, 

Oregon, and Washington and about 500 employees. 

Their mission is to generate and communicate scientific 

knowledge that helps people understand and make 

informed choices about people, natural resources, and 

the environment. The station publishes two newsletters 

about recent research: Science Findings and Science 

Update. 

These can be found at www.fs.fed.us/pnw/.

What Is the Cradle of Forestry

Interpretive Association? 

The Cradle of Forestry Interpretive Association (CFIA) 

is a nonprofit organization founded in 1972 by a group of 

people interested in forest conservation. The CFIA helps 

the Forest Service tell the story of forest conservation 

in America, and it helps people better understand both 

forests and the benefits of forest management. The CFIA 

invites everyone to visit its Forest Discovery Center in 

the Pisgah National Forest near Brevard, NC. 

Learn more about the CFIA by visiting

http://www.cradleofforestry.org.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, 

age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political 

beliefs, reprisal, or because all or part of an individual’s income is derived from any public assistance program. (Not all prohibited bases apply to 

all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, 

etc.) should contact USDA’s TARGET Center at (202) 720–2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, 

Office of Civil Rights, 1400 Independence Avenue, SW, Washington, DC 20250–9410 or call (800) 795–3272 (voice) or (202) 720–6382 (TDD). 

USDA is an equal opportunity provider and employer.
Review Board

Forest Service

http://www.fs.fed.us

Investi-gator

http://www.scienceinvestigator.org

Natural Inquirer

http://naturalinquirer.org

Forest Service Conservation Education

http://www.fs.fed.us/kids/ (Click on Conservation 

Education)

Forest Service Pacific Northwest Research Station

http://www.fs.fed.us/pnw/

Felida Elementary School, Vancouver, Washington, 

Mrs. Beaman’s 5th Grade Class

the Investi-g

Forest Service Pacific Northwest Research Station— 

For Kids

http://www.fs.fed.us/pnw/kids/

Forest Service Climate Change Resource Center

http://www.fs.fed.us/ccrc/

Discover the Forest

http://discovertheforest.org

National Oceanic and Atmospheric Administration 

Climate Change for Kids

http://www.education.noaa.gov/

Forest Service Northern Research Station—

Interactive Atlas of Climate Change: Bird & Tree 

Species 

http://www.nrs.fs.fed.us/atlas/

For additional information, please visit these Web sites: