Suggested levels for Guided Reading, DRA,™
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in the Pearson Scott Foresman Leveling Guide.
Life Science
Ecosystems of
the Rain Forests
Genre
Expository
nonfiction
Comprehension
Skills and Strategy
• Fact and Opinion
• Main Idea and
Details
• Graphic Organizers
Text Features
•
•
•
•
Captions
Diagram
Map
Glossary
Scott Foresman Reading Street 6.1.4
ISBN 0-328-13601-8
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by M . J.. Spackman
Vocabulary
basin
charities
equator
erosion
evaporates
exported
industrial
recycle
tropics
Reader Response
Ecosystems of
the Rain Forests
1. Read the following sentence: The rain forests are home to
a variety of animals and plants. Is this sentence a fact or an
opinion? How can you tell?
2. Using the diagram on page 17 for reference, tell something
you learned about each level of the rain forest. Make a
graphic organizer to help you.
3. Copy this chart on a separate piece of paper. Look the
words up in a dictionary and find forms of the words
that have different endings. Copy those words and their
meanings. Be prepared to use each word in a sentence.
Word
New word
New meaning
charity
evaporate
industry
4. What information does the caption on page 15 tell you
that is not provided by the photograph?
Word count: 1,790
by M. J. Spackman
Note: The total word count includes words in the running text and headings only.
Numerals and words in chapter titles, captions, labels, diagrams, charts, graphs,
sidebars, and extra features are not included.
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What Is a Rain Forest?
A rain forest is a wet, wooded place. In some rain
forests, as many as 400 inches of rain may fall in a year.
Rain forests have four layers. The lowest level is the
forest floor. The middle layers are the understory, which
is shaded by tall trees, and the canopy, which is like a
roof. The top layer is called the emergent layer. This is
where the tops of some trees rise above the canopy.
Rain forests are large ecosystems. Each life form
depends on the other life forms that live there.
Tropical rain forest
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correct errors called to its attention in subsequent editions.
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ISBN: 0-328-13601-8
Copyright © Pearson Education, Inc.
All Rights Reserved. Printed in China. This publication is protected by Copyright,
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4 5 6 7 8 9 10 V0H3 14 13 12 11 10 09 08 07 06
3
What Is an Ecosystem?
An ecosystem is made up of plants, animals, and
nonliving things that occupy an area. If one part of the
system is changed, the entire system may be affected.
Every natural environment—even your own flower
garden—is an ecosystem that has a cycle of life and death.
In your flower garden, the flowers depend on
earthworms that recycle nutrients in the soil. The bees
that visit the flowers help to produce a new generation
of plants. The life cycle continues as long as the
ecosystem is not disturbed. Rain also helps your flowers
grow. The moisture that is not used by the flowers
evaporates when the sun comes out. It is then recycled
when it becomes rain.
Within each ecosystem there are producers and
consumers. In a rain forest, the plants are producers.
They make food. Animals and humans are consumers.
They eat food. Organisms that cause decay, such as fungi
and bacteria, help break down food. They also create
nutrients for other living things.
A great variety of animals and plants make their
homes in rain forests. Unfortunately, rain forests are
disappearing at an alarming rate. Understanding
the ecosystems of rain forests can help us know how
important it is to save them.
Bees are needed for
flowers to live.
More than 2,000 kinds of butterflies call the
Atlantic coast rain forests home. Many of these
are in danger of extinction.
4
5
Two Types of Rain Forests
There are two types of rain forests. Steamy rain forests
are located in a region called the tropics. The tropics lie
near the equator. The weather there is warm and wet
all year long. There are now about two billion acres of
tropical rain forest. Once there were many more.
Rain forests also grow in a cooler, temperate climate.
There are only about 75 million acres of temperate rain
forests. Most of these stretch along the northwestern
coast of the United States. But there are also temperate
rain forests in New Zealand, Chile, and Australia. The
ecosystems of both types of rain forests are threatened
by human beings and our industrial world.
Tropic of Cancer
Equator
Tropic of Capricorn
The area of Earth that lies between the
Tropic of Cancer and the Tropic of Capricorn
contains the hot, wet regions known as
tropical rain forests.
6
7
The Tropical Rain Forest
Tropical rain forests are home to a huge variety of
plants and animals. In one four-square-mile section of a
rain forest in the Amazon River Basin of South America,
scientists have identified 750 kinds of trees.
8
The Forest Floor
The floor of a tropical rain forest is mostly free of
undergrowth. This is because very little sunlight can go
through the thick upper canopy and understory. Without
sunlight plants cannot live. The leaves, twigs, and dead
insects on the forest floor break down quickly in the
warm and wet conditions.
Underneath the decaying leaves are fungi. The fungi
feed off the decaying matter. This process enriches the
soil and tree roots.
The floor of the forest is also home to worms, insects,
ground-feeding birds, and snakes. Each of these creatures
has a role in the rain forest ecosystem.
9
One of the most interesting rain forest creatures is the
leaf-cutter ant. Ants live in a colony, or group. Each ant
has a job. Scout ants find trees. Large, strong-jawed ants
follow a trail left by the scout ants. The large ants cut the
leaves from the tree.
Other ants carry the leaves back to the colony. They
are helped by small ants that ride on top of the leaves to
protect them from flies. In the colony, the ants chew the
leaves into a pulp. That will feed the fungi that serve as
the ants’ food. Once again, a cycle is formed.
Rain forests of the Amazon Basin and Malaysia may
be flooded many months of the year. Many of the trees
are completely covered by water, yet they survive this
flooding.
The fish that swim in the flooded forest depend on the
trees above for food. The trees produce fruit that drops
into the water and is eaten by fish. The trees also depend
on the fish. When the fish eat the fruit, they scatter the
seeds. Then the seeds can grow into more trees.
It might seem that the forest floor would be deep
with rich soil that is good for farming, but this is not
true. The soil is thin and nutrient-poor because too
many plants grow in it.
Leaf-cutter ants at work
Leaf-cutter ants live in colonies.
10
A young person
canoeing in the
Amazon Basin
in Brazil
11
Here is another example of how living things depend
on one another. There is a certain orchid in the rain
forests of the Amazon Basin. This orchid depends on
one kind of bee for pollination. If conditions in a forest
change so that the bee cannot survive there, the orchid
also disappears.
The Brazil nut tree depends on this same orchid for
pollination. A planter who grows Brazil nut trees must
also grow the kind of orchid that the bees draw nectar
from. Otherwise, the trees will not produce nuts.
The Understory
Between the forest floor and the canopy is the
understory. Plants that live in this layer are either shadelovers or young trees trying to reach sunlight above.
When a large tree falls, it often pulls down other
trees. The fallen trees create a light gap.
Sunlight fills the gap. The young trees, climbing vines,
and seeds on the forest floor use the light to grow.
Among the greenery and branches of the understory,
birds and insects fly.
Plants that live on trees often produce blooms that
appear to grow from the tree trunks. These flowers,
including orchids, attract hummingbirds that feed on the
nectar and assist in the plant’s pollination.
12
The hummingbird’s long
pointed beak allows it to
easily drink the nectar of the
rain forest’s flowers.
13
Small mammals swing and scramble among the
branches and vines of the understory. They climb easily
with their handlike paws and quick feet. Among these
is the lemur of Madagascar, an island nation off the east
coast of Africa.
Lemurs are endangered animals. Before human beings
arrived in Madagascar, fourteen more species of lemur
lived in the rain forests. The larger lemurs were hunted to
extinction. Today, charities are collecting funds to protect
the remaining lemurs and their habitat.
A ring-tailed lemur
leaps from tree to tree.
Another endangered rain forest mammal is the jaguar.
The jaguar is at the top of the food chain in the rain
forest. If it disappears, the populations of the animals it
feeds on may increase too much. Then the balance of the
ecosystem may be upset.
14
15
A sloth
hangs
high in a
tree in the
rain forest
canopy
The canopy trees support vines and even other trees.
One is the strangler fig. The seed of this tree grows in
branches of another tree. It then sends a root down the
trunk of its host tree to the ground. There it begins to
grow more roots, stems, and leaves. The strangler fig’s
roots cover the host tree, causing it to die. However, its
fruit feeds monkeys and birds. So the strangler fig is an
important part of the ecosystem.
The sloth lives its entire life in the canopy. Sloths have
adapted so well to life in the treetops that they almost
never come to the ground. They can no longer walk
upright when they do.
Emergent Tree
The Canopy
The tops of the tall trees of the rain forest form
its canopy. It is like an umbrella above the forest. The
canopy is exposed to the sun, heat, wind, and rain.
The emergent trees above the canopy are even more
exposed. The emergent trees and the canopy trees
capture the solar energy that fuels the entire rain forest
ecosystem. Most of the organisms of the rain forest live in
the trees of the canopy.
Some trees provide woods used around the world.
Mahogany, a reddish-brown wood used in furniture
and boat frames, comes from tropical rain forests. It is
becoming more rare and expensive.
Teak, rosewood, and ebony are also exported by rain
forest countries to sell around the world. The lumber
industry provides employment and income for people. But
it also endangers the ecosystem of the rain forest.
16
Canopy
Understory
17
The Temperate Rain Forest
The temperate rain forests are not as warm as the
tropical rain forests. Usually, high temperatures in the
summer are about 70 degrees Fahrenheit, and high
temperatures in the winter stay around 40 degrees
Fahrenheit.
The temperate rain forest does not receive the same
rain as the tropical rain forest. Still, there can be up to
167 inches of rain a year.
The Canopy
The living things in the temperate rain forest also
depend on one another. The Douglas fir’s needles are
home to fungi, algae, and bacteria. The tiny bacteria
draw their nutrition from the tree, and they also protect
it. Other organisms on the tree might harm it if the
bacteria were not there for them to eat.
As in the tropical rain forest, some trees grow on
other trees. The big-leaf maple tree sends tiny roots into
other plants to draw nutrients from them.
18
19
The Understory
In the Olympic Rain Forest of the northwest United
States, elk are important. They play a special part in the
ecosystem of the understory. Scientists fenced off areas of
the rain forest to see what happens when elk cannot go
there. Several problems occurred. The open space of the
understory became tangled with plants.
The plants then had to fight for space. Some plants
that died off were the elks’ most healthful food. The
elk could not find the food they needed. In addition,
there are bears that feed on the grass underneath those
plants. They also lost their food source, because the grass
became a tangle of vines and roots.
20
21
The Forest Floor
The trunks of fallen trees are an important part of
the forest floor’s ecosystem. At one time, people thought
that the giant logs were just another kind of forest
waste. But these dead tree trunks, called nurse logs, are
important. They help prevent erosion, and they give
shelter to snakes, chipmunks, and birds.
The nurse logs also offer a rich bed for tree seedlings.
When a tree falls and its enormous trunk becomes a
nurse log, it decays to become a plant nursery. The cycle
of life continues.
Summary
We have learned how the ecosystems in the rain
forest work. We know that all living things in the rain
forest depend upon one another. We also know that
humans can affect the future of the rain forest. If we
continue to change the rain forest, we may kill off many
of its living things. We must protect the ecosystem of this
special environment.
22
23
Glossary
Vocabulary
basin
Reader Response
basin n. an area drained by
a river or tributary.
exported v. transported or
traded abroad.
charities n. groups that help
or assist.
industrial adj. characterized
by highly developed
industries.
charities
equator
equator n. the imaginary
circle around Earth’s surface
that divides Earth into the
Northern and Southern
Hemispheres.
erosion
evaporates
erosion n. an act or process
of wearing away.
exported
evaporates v. converts or
changes into vapor.
recycle v. reuse or adapt to
another use.
tropics n. region of Earth’s
surface lying between
the Tropic of Cancer and
The Tropic of Capricorn
(23°45 north to 23°45 south
latitudes).
industrial
recycle
tropics
Word count: 1,790
Note: The total word count includes words in the running text and headings only.
Numerals and words in chapter titles, captions, labels, diagrams, charts, graphs,
sidebars, and extra features are not included.
24
1. Read the following sentence: The rain forests are home to
a variety of animals and plants. Is this sentence a fact or an
opinion? How can you tell?
2. Using the diagram on page 17 for reference, tell something
you learned about each level of the rain forest. Make a
graphic organizer to help you.
3. Copy this chart on a separate piece of paper. Look the
words up in a dictionary and find forms of the words
that have different endings. Copy those words and their
meanings. Be prepared to use each word in a sentence.
Word
New word
New meaning
charity
evaporate
industry
4. What information does the caption on page 15 tell you
that is not provided by the photograph?