GenreGenre Comprehension SkillComprehension Skill Text FeaturesText Features Science ContentScience Content Nonfi ctionNonfi ction Main Idea and DetailsMain Idea and Details • Captions• Captions EcosystemsEcosystems • Labels• Labels • Text Boxes• Text Boxes • Glossary• Glossary Scott Foresman Science 3.3Scott Foresman Science 3.3 ì<(sk$m)=bdibfj<ì<(sk$m)=bdibfj<ISBNISBN 0-328-13815-00-328-13815-0 +^-Ä-U-Ä-U+^-Ä-U-Ä-U
Vocabulary What did you learn? community desert 1. What happens when one part of ecosystem an ecosystem changes? environment grassland 2. Why can’t trees grow in population some grasslands? tundra wetland 3. Lemmings are able to live on the tundra. Why? by Barbara Fierman 4. You have read about the importance of prairie dogs in their habitat. Write to explain the things that prairie dogs do to help keep other living things alive. Picture Credits 5. Main Idea and Details A tropical Every effort has been made to secure permission and provide appropriate credit for photographic material. The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions. forest is one kind of ecosystem. List Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd). Opener: Digital Vision; 1 Getty Images; 3 (T) Getty Images; 5 Getty Images; 7 ©Jerry Young/DK Images; 8 Tom Bean/Corbis; some details from the book about 11 Digital Vision; 12 Francois Gohier/Ardea; 14 Getty Images; 15 Digital Vision; 16 (BC) ©Jerry Young/DK Images; this forest. 18 (Bkgd) Getty Images; 22 (CR) Tom Bean/Corbis, (BC) Digital Vision; 23 (CR) Francois Gohier/Ardea, (BC) Getty Images. Scott Foresman/Dorling Kindersley would also like to thank: 10 (BC) Jerry Young/DK Images. Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson. ISBN: 0-328-13815-0 Copyright © Pearson Education, Inc. All Rights Reserved. Printed in the United States of America. This publication is protected by Copyright, and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic, mechanical, photocopying, recording, or likewise. For information regarding permission(s), write to Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025. 3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 05
Places For Living Things Living things get what they need from where they live. A living thing’s environment is everything that is around it. Plants and animals are living parts of an environment. Some nonliving parts are sunshine, water, soil, and weather. Sunshine warms the air, water, and soil. It allows plants and animals to live in those places. Water and soil are important parts of the environment. Water falls as rain and snow. It goes into the soil. Some soils hold a lot of water. Other soils hold very little. Plants need different types of soil. Climate is the weather a place has during the year. In some places, the climate is cold and dry. In other places, the climate is hot and wet. Many places have climates with changing seasons. A moose’s environment is a coniferous forest. 2 3
Parts of an Ecosystem Special Homes Every plant and animal has a special place to live. This place is called its habitat. Living things get what they need in their habitat. Plants get light, air, water, and space to grow. Animals get food, water, and a space to live and grow. If one part of a habitat is taken away, the habitat will change. If prairie dogs leave their habitat, the animals that use the prairie dog holes might have to move or find other places to live. Prairie dogs live in underground holes. Plants and animals live where they have water, food, and shelter. An ecosystem contains all the plants, animals, and nonliving things in an environment. The different parts of an ecosystem work together. Prairie dogs dig holes in the soil. This gives the soil more air. The air helps the grass grow. This makes more grass for animals to eat. The living parts of an ecosystem also need each other. Burrowing owls and other animals often use the holes dug by prairie dogs. The cactus lives in a desert habitat. 4 5
Groups within Ecosystems Ecosystems Change Sometimes ecosystems change. First, one part of the ecosystem changes. Then the other parts change too. Long ago, many wolves lived in Yellowstone National Park. The wolves ate elk and other animals. People wanted to get rid of the wolves. They killed many of them. When the wolves were gone, there were not enough animals to eat the elk. Yellowstone’s elk population grew out of control. There were too many elk and not enough food. Many of the elk died. Finally, people devided to bring wolves African elephants back to the park. The elephants live by a lake. They live together. The elephants are able to get water and rest at the lake. They take care of each other. The elephants Gray wolf make up a population. Birds come to live at the lake. They make nests and find fish in the lake. Other animals find food at the lake too. The elephants, birds, and other animals each belong to their own populations. Together they make up a community of animals. The animals in the community need each other and the lake in order to live. 6 7
Grassland Some grasslands get more rain than other grasslands. Tall grasses can grow in A grassland is a large, flat area of land that is these grasslands. Short grasses grow where covered with grass. There are grasslands all over there is less rainfall. Wildflowers grow in the world. The grasslands of North America and grasslands too. Asia usually have cold, snowy winters and hot Many animals live in a grassland summers. African grasslands are much warmer. ecosystem. Rabbits, deer, and prairie dogs In some grasslands the soil is too dry for eat the grasses. Foxes, snakes, and other trees to grow. Trees need more water than the animals eat the smaller animals. Birds such grassland gets. as owls and sparrows also live in grasslands. During the spring and summer, it rains in the grassland. The rain soaks into the ground. The grasses have long roots that go deep into the ground. These roots can get water in the American bison, or buffalo, live in drier seasons. the grasslands of North America. 8 9
Desert A desert is a place that gets very little rain. Most deserts get less than five inches of rain a year. During the day the desert can be very hot. At night it is much cooler. The plants and animals in the desert need each other. All of the desert’s living things have found ways to stay alive without needing much water. One kind of desert plant is the cactus. Cactuses keep water in their stems. Their roots spread out to get water from the soil. They have special skin that keeps water in. Desert animals hide when it is hot. Some sleep in the shade of plants. Others, such as some frogs and toads, dig tunnels under the ground. Desert animals such as snakes and coyotes often go out at night when it is cool to hunt for birds and other small animals. When days are hot, the rattlesnake hunts at night. 10 11
Tundra Other plants, such as grasses and wildflowers, can grow there. These plants are small and have The Arctic tundra is a very cold and dry short roots. Many tundra plants have tiny hairs ecosystem. It is located near the North Pole. on their stems or leaves. The hairs help protect Winters on the tundra are long and cold. the plants from the wind. Some snow falls, and it is very windy. The days In the summer, ponds form on the tundra. are short, and the nights are very long. For many Ducks, geese, and other birds make nests near weeks the Sun does not shine at all. The ground the ponds. There are many insects to eat during is frozen all the time. the tundra summer. Most of the birds in the Summers on the tundra are short and cool. tundra fly to warmer places in the winter. The days are long and sunny. In some places, Lemmings are small animals that live in the the Sun shines twenty-four hours a day. The snow tundra. They dig in the snow to find grass, moss, melts, but the soil under the ground stays frozen. and twigs to eat. They have thick fur that helps Many plants, such as trees, can’t grow in keep them warm. the tundra. In fact, the word tundra means “treeless land.” Most of the tundra’s flowers and plants are small. This helps protect them from the strong winds. 12 13
Coniferous Forest Deciduous Forest Earth has many different kinds of forests. Deciduous forests grow where it rains in the Each forest has its own plants and animals. summer and snows in the winter. In the fall, Coniferous forests grow in places with the leaves on deciduous trees change color. warm summers and cold, snowy winters. They change from green to yellow, orange, or red. Coniferous trees have leaves that look like Then the trees drop their leaves. In the spring, needles. Both spruce and pine trees are conifers. they grow new leaves that stay green all summer. Coniferous trees grow close together. Both oak and maple trees are deciduous. This helps protect them from the cold and It is easier for plants to grow in deciduous wind. It is hard for plants to grow under conifers. forests. Flowers, ferns, and moss grow on the They don’t get enough sunlight. Moss, however, deciduous forest floor. grows beneath these trees. Many animals live in a deciduous forest. Many animals, such as bears, live in coniferous Insects, birds, and small animals make their forests. Bears have thick fur to help them stay homes in the trees. Many small animals eat the warm. They sleep through the cold winters. Birds trees’ leaves, nuts, and seeds. Owls and foxes eat seeds from the trees in summer. Then they fly live in deciduous forests. They find squirrels to warmer places in winter. and other small animals to eat. 14 15
Tropical Forest Orchids are air plants. Tropical forests grow in places that are mostly Their roots dangle warm and wet all year long. The trees that grow in the air to get food and water. there are very tall. Some tropical forest trees are as tall as a ten-story building! The leaves on top of the trees keep much of the sunlight out. Many plants can’t grow under the trees because they don’t get enough sunlight. Some plants can grow on the branches and trunks of the trees. These plants are called air plants. They get water and food from the air. Vines also grow on the trees. Many animals live in the tropical forest. Most live in the trees. Frogs and spiders live under the leaves. Ants and beetles live under the bark. Snakes wind around the trunks. Monkeys swing from tree to tree, and colorful birds sit on the branches. Many, many insects live in tropical forests. How many? So many that scientists haven’t even named them all! Many tropical forest insects are hard to see. They look like sticks or leaves. 16 17
Freshwater The largest freshwater wetland is in Brazil. Ecosystems Many large rivers run through Brazil. When it rains, these rivers can overflow, flooding the surrounding land. The flooded land becomes Some ecosystems have fresh water. Other a wetland habitat for many plants and animals. ecosystems have salt water. In some places Many birds stay in the wetlands of Brazil for fresh water and salt water come together. a short time while they are traveling to other Lakes, ponds, rivers, and streams are all places. Many fish live there too. The wetlands freshwater ecosystems. Lakes and ponds have of Brazil are also home to capybaras. They have land all around them. In rivers and streams, webbed feet, like a duck. Their webbed feet the water moves from one place to another. help them swim. The water in some lakes and rivers comes from under the ground. The water in others comes Capybaras’ eyes and ears are on top of from rain or melting snow. their heads. This helps them to see and hear when swimming. A wetland is land that is covered by water most of the time. Trees, grasses, and plants grow in a wetland. Many animals live there too. Some wetland birds have long legs that help them walk in the water. They have beaks for catching fish to eat. Wetland frogs and toads can live in the water and on the land. 18 19
Saltwater Ecosystems Rivers flow into oceans. The fresh water Earth’s oceans contain almost all of its salt from rivers mixes with salt water from the ocean. water. They cover most of the planet. Near the When this happens, salt marshes are formed. land, the ocean is not very deep. Clams, crabs, A salt marsh is a type of wetland. Most of and some kinds of fish live there. the salt marsh is covered with water. Many Far from land, the ocean water is deep. Large grasses grow in the salt marsh. These grasses fish, sharks, and whales can live in deep water. can live in water and soil that is salty. The deepest parts of the oceans are dark and Some of the animals in the salt marsh cold. Very few plants can grow there because are so small that you can’t see them. Many there is little sunlight. sea animals start their life in salt marshes before moving out to the ocean. Flamingos eat the tiny insects and plants found in salt marshes. 20 21
The World Around You We have now talked about many ecosystems. Ecosystems’ constant changes can be difficult Yet there are still thousands more, found all over and confusing to track. Many people try to get Earth. Ecosystems are everywhere. But they are rid of that confusion by thinking of Earth as difficult to define and measure because they are one big ecosystem! However you like to think always changing. Climate changes. Hurricanes, and about it, one thing is for certain: ecosystems need volcanic eruptions change ecosystems. Human to be protected, so every living plant and animal activities and the interactions between plants and can have a home. animals also change ecosystems. Tundra Coniferous forest Grassland Tropical forest Desert Wetland 22 23
GlossaryVocabulary What did you learn? community desert 1. What happens when one part of community a group of different types of an ecosystem changes? ecosystem animals living together in one environmentplace and needing each other grassland 2. Why can’t trees grow in to live some grasslands? population deserttundra a place that gets very little rain ecosystemwetland all of the different plants, animals, 3. Lemmings are able to live on and nonliving things in one place the tundra. Why? that use each other environment everything surrounding a 4. You have read living thing about the importance of prairie dogs in their habitat. Write to explain the grassland a large, flat area of land that is things that prairie dogs do to help covered with grass keep other living things alive. population all the living things of one kind Picture Credits in one place 5. Main Idea and Details A tropical Every effort has been made to secure permission and provide appropriate credit for photographic material. The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions. forest is one kind of ecosystem. List Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd).tundra a cold and dry area where some Opener: Digital Vision; 1 Getty Images; 3 (T) Getty Images; 5 Getty Images; 7 ©Jerry Young/DK Images; 8 Tom Bean/Corbis;part of the ground or soil is frozen some details from the book about 11 Digital Vision; 12 Francois Gohier/Ardea; 14 Getty Images; 15 Digital Vision; 16 (BC) ©Jerry Young/DK Images; this forest. 18 (Bkgd) Getty Images; 22 (CR) Tom Bean/Corbis, (BC) Digital Vision; 23 (CR) Francois Gohier/Ardea, (BC) Getty Images.for the entire year Scott Foresman/Dorling Kindersley would also like to thank: 10 (BC) Jerry Young/DK Images. Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson.wetland a land that traps water or stays covered in water for most of the year ISBN: 0-328-13815-0 Copyright © Pearson Education, Inc. All Rights Reserved. Printed in the United States of America. This publication is protected by Copyright, and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic, mechanical, photocopying, recording, or likewise. For information regarding permission(s), write to Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025. 3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 0524
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