life in the biosphere

Scott Foresman Science 6.6 Genre Comprehension Skill Text Features Science Content Nonfi ction Main Idea and Details • Captions • Diagrams • Glossary Biomes ISBN 0-328-13986-6 ì<(sk$m)=bdjigg< +^-Ä-U-Ä-U 13986_01-04_CVR_FSD.indd Cover113986_01-04_CVR_FSD.indd Cover1 5/12/05 1:34:29 PM5/12/05 1:34:29 PM Scott Foresman Science 6.6 Genre Comprehension Skill Text Features Science Content Nonfi ction Main Idea and Details • Captions • Diagrams • Glossary Biomes ISBN 0-328-13986-6 ì<(sk$m)=bdjigg< +^-Ä-U-Ä-U 13986_01-04_CVR_FSD.indd Cover113986_01-04_CVR_FSD.indd Cover1 5/12/05 1:34:29 PM5/12/05 1:34:29 PM 1. How does a population differ from a community within an ecosystem? 2. Why are organisms in a biome similar even if they live many thousands of miles apart? 3. How does the canopy of a dense forest affect the plants on the fl oor of the forest? 4. One way that plants adapt to different conditions is their shape. Write to explain how climate can affect the shape of the main plants in a biome. Include details from the book to support your answer. 5. Main Idea and Details Make a graphic organizer. Complete the details that support this main idea: A population is a group of individuals of the same species that live in an area. What did you learn? Vocabulary abiotic factors adaptation biome biotic factors community ecosystem environment population Picture Credits 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. Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd). 1 Digital Stock; 2 (B) Getty Images; 4 (B) Getty Images, (T) Getty Images; 6 (B) Getty Images; 8 (B) Getty Images, (TL) Digital Vision; 9 (BC) Digital Vision; 10 (B) Getty Images, (TL) Getty Images; 11 (T) Brand X Pictures; 12 (B) Getty Images; 13 (T) Getty Images, (BR) Digital Vision; 14 (B) Getty Images; 15 (R) Getty Images; 16 Getty Images. Scott Foresman/Dorling Kindersley would also like to thank: Opener: (C) ©Jerry Young/DK Images; 12 (BC) ©Jerry Young/DK Images; 15 (BC) ©Jerry Young/DK Images. Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson. ISBN: 0-328-13986-6 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 13986_01-04_CVR_FSD.indd Cover213986_01-04_CVR_FSD.indd Cover2 5/12/05 1:34:50 PM5/12/05 1:34:50 PM by Steve Miller 13986_05-20_FSD.indd 113986_05-20_FSD.indd 1 5/12/05 1:35:41 PM5/12/05 1:35:41 PM 2 How are organisms on Earth connected? The biosphere is the part of Earth where living things are found. The whole land surface of the planet is part of the biosphere. It also includes the atmosphere to about ten kilometers high and the oceans, from the surface to the deepest parts, eleven kilometers below the surface. No matter how cold or hot, wet or dry, there are living things in all these places. All these organisms—plants, animals, and bacteria—share resources such as light, water, and air. As a result, life on the planet is connected. When something happens to one living thing, it affects those around it. The science called ecology studies how living things affect one another. The biosphere includes all living things—even the people who live in this city. Connections in the Biosphere 13986_05-20_FSD.indd 213986_05-20_FSD.indd 2 5/12/05 1:36:02 PM5/12/05 1:36:02 PM 3 Organization of the Biosphere What did you do before school today? Maybe you ate an apple, played with your baby sister, or drank a glass of water. Each of these activities is an interaction with something or someone else. Everything that you do, even breathing the air, affects things around you, and they affect you. The things around you make up your environment. An organism’s environment is anything that can affect it. This includes living things, such as trees and plants, or any pet you might have. It also includes nonliving things, such as water and air. Within an environment, there can be many different organisms of one species. A population is a group of individuals of the same species that live in one area. The frogs in the picture make up a population. The dragonfl ies are another population. If there were two kinds of frogs, they would make two different populations. That is because they are different species. There is also a population of each kind of plant and each species of fi sh in the pond. How do the populations of frogs and dragonfl ies interact with one another? 13986_05-20_FSD.indd 313986_05-20_FSD.indd 3 5/12/05 1:36:42 PM5/12/05 1:36:42 PM 4 In an environment, many different populations live together. A community is a group of populations that interact with each other in an area. A pond community includes frogs, dragonfl ies, other insects, and fi sh. It also includes all the plants that provide food and shelter for these animals. Some parts of the community are hidden, such as bacteria that are too small to see. These living things affect one another. Some are food for others. Some compete for the same resources. For example, frogs and lizards may both eat the same insects. Communities of organisms also rely on nonliving parts of the environment for many of their needs. Each organism has needs for air, water, minerals, and shelter. The entire community of living things, along with the nonliving parts of the environment, is called an ecosystem. An ecosystem can be very small. The plants and animals in the terrarium are part of a tiny ecosystem. They interact with one another and with the air, water, and rocks. Other ecosystems are very large. These bison and the grasses they eat are part of a prairie ecosystem that once covered much of North America. The population of bison needs the prairie grasses for food. 13986_05-20_FSD.indd 413986_05-20_FSD.indd 4 5/12/05 1:37:04 PM5/12/05 1:37:04 PM 5 The Needs of Organisms The organisms that live in an ecosystem are called the biotic factors. In the prairie, the biotic factors include the bison and other animals. The grasses and wildfl owers provide food for the bison, many of the birds, and small prairie animals, such as mice. Although you cannot see them in the picture, microorganisms, such as bacteria, live in all parts of the ecosystem. Some of the microorganisms live inside the bison’s digestive system. They are also biotic factors of this ecosystem. Living things provide for many of the needs of plants and animals. Other needs are provided for by the nonliving part of the environment, called the abiotic factors. These include water, air, sunlight, and even temperature. All these factors affect what types of organisms can survive in the ecosystem. A terrarium is an ecosystem because it has a community of living things. 13986_05-20_FSD.indd 513986_05-20_FSD.indd 5 5/12/05 1:38:13 PM5/12/05 1:38:13 PM 6 What are Earth’s biomes? Certain kinds of large ecosystems occur at different places around the world. The plants and animals of the Mohave Desert in the southwestern United States look a lot like those in the deserts of northern Africa and central China. This is because the climates of those regions are similar—very dry with hot days. All these desert ecosystems are similar. A biome is a large group of ecosystems with similar climates and organisms. The Mohave is part of the desert biome. This map shows the locations of some of the major biomes on Earth. Climate and Biomes Deciduous forests are located in the Northern Hemisphere between the hot tropics and cold polar regions. These forests have warm summers and cold winters. Grasslands are found on every continent except Antarctica. Large grazing animals live in herds in many grasslands. 13986_05-20_FSD.indd 613986_05-20_FSD.indd 6 5/12/05 1:38:55 PM5/12/05 1:38:55 PM 7 tundra Taiga is the evergreen forests that cover much of the northern parts of North America, Europe, and Asia. The taiga plants and animals are adapted to survive short summers and long, cold winters. Tundra is the biome in the Arctic areas where the growing season is too short for trees. Tundra temperatures are cool in summer and very cold in winter. Below the surface of the ground is a layer of soil that never thaws. Rain forests are located near the equator. They have warm, wet climates and a year- round growing season. In many rain forests, the temperature always stays above the freezing point of water. Deserts are ecosystems that receive less than 25 cm of rainfall each year. Many desert plants grow very quickly after a rainfall and then stay dormant for months until the next rain. A biome is not one specifi c area. It consists of ecosystems from different parts of the world that have similar climates and organisms. rain forest grassland desert taiga deciduous forest mountainous areas polar regions 13986_05-20_FSD.indd 713986_05-20_FSD.indd 7 5/12/05 1:39:26 PM5/12/05 1:39:26 PM 8 Why are the plants and animals in a biome similar, even if they are on different continents? Organisms have features that suit the biotic and abiotic factors of an ecosystem. In places that have similar climates, the abiotic factors are often quite similar. The plants and animals also have similar adaptations. An adaptation is a characteristic that helps an organism live and reproduce in an environment. The two plants on this page have adaptations to help them survive in similar environments. You may be familiar with cactus plants, such as the saguaro cactus shown here. Cactuses are found in many parts of North and South America. Adaptations help them survive in an environment that has high temperatures and very little water. The saguaro has soft, wet tissues full of water, and a thick skin to hold the water in the plant. There is very little rain in the desert, so the plants grow slowly. The spines on the cactus protect it from hungry animals. Now look at the picture of the euphorbia plant. It looks a lot like the saguaro cactus. It has soft, moist tissues, a thick skin, and protective spines. However, the euphorbia grows in Africa and is not a very close relative of the cactus plant. The two plants show similar adaptations to the hot, dry climate of their biomes. The saguaro cactus has adapted to an environment with very little water. Adaptation Although they look similar, this euphorbia is not a close relative of the cactus. 13986_05-20_FSD.indd 813986_05-20_FSD.indd 8 5/12/05 1:39:48 PM5/12/05 1:39:48 PM 9 Characteristics of Biomes Climate is one factor that determines what types of organisms live in a particular place. In warm areas with a lot of rain, plants grow very quickly. Because there are a lot of leaves to provide food and shelter, there are usually a lot of animals as well. The tropical rain forests have many more species than other biomes. Most of these species would not be able to survive in cold climates. They might do well in a different rain forest, though. Their adaptations suit a particular biome. Even though the ecosystems within a biome are similar, they are not exactly alike. These elephants live in the grasslands of Kenya in Africa. You can tell at a glance that they are different from the bison you saw before. The bison have long fur to protect them from the cold winters on the American plains. The elephants, on the other hand, have very little hair because the temperature rarely drops below freezing in the grasslands of Kenya. Like bison, elephants live in a grassland biome. 13986_05-20_FSD.indd 913986_05-20_FSD.indd 9 5/12/05 1:40:15 PM5/12/05 1:40:15 PM 10 The living things in the deciduous forests have adaptations that suit cold winters and hot, rainy summers. The trees have wide leaves that gather lots of light during the growing season. The plants that grow on the forest fl oor must adapt to less sunlight because of the shade from the trees. As cold weather and shorter days approach, the trees stop producing food. The leaves change color and then fall. The fl oor of a deciduous forest is covered with rich soil produced by decaying leaves. The leaves and soil provide food and shelter for many species of plants and animals. Many insects and caterpillars feed on the nutritious leaves of the trees. They become food for other animals, such as spiders, toads, moles, and birds. Larger animals that are common in this biome include skunks, raccoons, coyotes, deer, and bears. Because there is less food in the winter, some of the animals of the forest hibernate. Others, especially birds, migrate—that is, they move to places with a warmer climate—until spring. slug Deciduous Forests If these trees did not lose their leaves in winter, the weight of the snow could break the branches. The decaying leaves are home to many species of animals and plants. earthworm centipede 13986_05-20_FSD.indd 1013986_05-20_FSD.indd 10 5/12/05 1:40:53 PM5/12/05 1:40:53 PM Taiga Because of the shape of these trees, snow falls off them. The taiga, or coniferous forest, covers areas of Alaska, Canada, northern Europe, and Russia. These forests have evergreen trees, such as pine, spruce, and fi r, which stay green all year long. This is an adaptation for short growing seasons. Too much energy would be lost if the trees had to make new leaves every spring. Most of the trees of the taiga produce nutlike seeds in cones. The seeds feed insects, birds, and small mammals, such as squirrels and mice. Because the climate is wet, there are plenty of places for insects to live. Many kinds of insect-eating birds live in this forest. Many of the birds migrate to warmer areas in winter. Other animals are adapted to the cold winters. Some of the small mammals burrow underground to escape the cold. Others, such as brown bears and bats, hibernate through the winter, surviving by using fat stored in their bodies from the summer. Wolves, mink, and grizzly bears have thick winter coats, and they hunt other animals even in very cold weather. The dormouse becomes fat in the summer and autumn, and hibernates in the winter. 11 13986_05-20_FSD.indd 1113986_05-20_FSD.indd 11 5/12/05 1:41:20 PM5/12/05 1:41:20 PM The living things in tropical rain forests have adaptations for hot, wet weather. This biome is located all around the world near the equator. Plants grow all year in the rain forest and don’t lose their leaves in winter. The tropical rain forest grows in layers. Giant trees grow about seventy-fi ve meters tall. Their leaves form a dense cover, called the canopy, which absorbs most of the light from the Sun. Thick vines climb up the trunks of the trees into the canopy and compete with the trees for sunlight. Below the canopy is a middle layer of vines, smaller trees, ferns, and palms. Many of these plants have huge leaves to capture as much light as possible. An amazing number of plants and animals live in the rain forest. Some of them spend their whole lives in one tree. Because the climate is mild, there are many birds, reptiles, and amphibians. There are so many species in the rain forests around the world that scientists are constantly discovering new ones. Rain Forests The rain forest grows in layers of plants competing for sunlight. Many reptiles and amphibians have adaptations that suit the hot, wet climate of the rain forest. 12 13986_05-20_FSD.indd 1213986_05-20_FSD.indd 12 5/12/05 1:41:46 PM5/12/05 1:41:46 PM Grasslands Grasslands are generally fl at, open areas that get some rain, but not enough for large trees. There are grasslands on every continent except Antarctica. Grasses have deep roots, an adaptation that helps them survive the low amounts of rainfall in these areas. The height of the grass ranges from twenty centimeters to over two meters. Many roots extend more than two meters below the surface. During long dry periods or cold winters, the part of the grass plant above ground dies, but the deep roots are protected in the soil. When conditions are right, the grass begins to grow again. The grasslands generally have good soil and produce a large amount of grasses and other fl owering plants. Many animals graze in these open lands. Grasslands are home to many large animals, such as bison, elephants, rhinos, and antelope. Many smaller mammals tunnel in the ground among the grass roots. Predators, including lions, panthers, owls, and hawks, hunt in the grass. Many animals, such as these meerkats, fi nd shelter in underground burrows. When there is little rain, the grass above ground dies, but the deep roots are ready for the next rainy season. 13 13986_05-20_FSD.indd 1313986_05-20_FSD.indd 13 5/12/05 1:42:35 PM5/12/05 1:42:35 PM Desert The key characteristic of the desert biome is that it is very dry. People often think of deserts as hot, but any area that gets little rain is a desert, even parts of Antarctica. Desert plants have adaptations that help them survive with little water. In general, they are small, compared to plants in other biomes, and they grow slowly. In the Americas, many desert plants are cactuses. Similar plants grow in other deserts. In hot deserts, animals are usually active at night, when the temperature is much lower. Because there is a limited amount of shelter and food, there are not many large animals in deserts. Small mammals, snakes, lizards, and spiders are found in hot deserts. Many animals burrow under the ground where it is cooler during the day. Because there is so little rain, deserts do not have a canopy. Leaves are small and thick to save moisture. Many of the small mammals that live in the desert come out at night when it is cooler. This owl’s excellent vision and hearing help it fi nd the animals it hunts for food. 14 13986_05-20_FSD.indd 1413986_05-20_FSD.indd 14 5/12/05 1:43:07 PM5/12/05 1:43:07 PM 15 Tundra Some tundra animals, such as this fox, have white winter coats that make them hard to see on the snowy tundra. The tundra is a biome that combines cold temperatures, a short growing season, and limited water. Most of Earth’s organisms could not survive there. The tundra surrounds the Arctic, north of the taiga. Just below the surface is a permanently frozen soil layer called permafrost. When the top layer thaws in summer, water from the melted ice stays close to the surface. Although the growing season is short—two to four months— there are plants that grow in the tundra. Short bushes and shrubs, mosses, and grasses are the most common plants. Animals that live in the tundra have adaptations that help them survive in cold, windy conditions. Most birds migrate when temperatures grow too cold for the insects that they eat. Many small mammals survive by eating the tundra plants. Larger herbivores such as caribou and reindeer move across large distances looking for food. Foxes and wolves prey on these animals, and polar bears catch seals and other marine animals for food. Like the desert, the tundra has little water. Plants must also adapt to extremely cold winters. 13986_05-20_FSD.indd 1513986_05-20_FSD.indd 15 5/12/05 1:43:37 PM5/12/05 1:43:37 PM 16 Glossary abiotic factors nonliving parts of an ecosystem, such as air, water, or minerals adaptation a characteristic that helps an organism to survive in an environment biome a large group of ecosystems that have similar climates and organisms biotic factors the living parts of an ecosystem, such as plants, animals, and bacteria community a group of populations of living organisms that live and interact in an area ecosystem an entire community of organisms as well as the nonliving things with which they interact environment the things that affect an organism population the organisms of one species that live and interact in an area 13986_05-20_FSD.indd 1613986_05-20_FSD.indd 16 5/12/05 1:43:47 PM5/12/05 1:43:47 PM 1. How does a population differ from a community within an ecosystem? 2. Why are organisms in a biome similar even if they live many thousands of miles apart? 3. How does the canopy of a dense forest affect the plants on the fl oor of the forest? 4. One way that plants adapt to different conditions is their shape. Write to explain how climate can affect the shape of the main plants in a biome. Include details from the book to support your answer. 5. Main Idea and Details Make a graphic organizer. Complete the details that support this main idea: A population is a group of individuals of the same species that live in an area. What did you learn? Vocabulary abiotic factors adaptation biome biotic factors community ecosystem environment population Picture Credits 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. Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd). 1 Digital Stock; 2 (B) Getty Images; 4 (B) Getty Images, (T) Getty Images; 6 (B) Getty Images; 8 (B) Getty Images, (TL) Digital Vision; 9 (BC) Digital Vision; 10 (B) Getty Images, (TL) Getty Images; 11 (T) Brand X Pictures; 12 (B) Getty Images; 13 (T) Getty Images, (BR) Digital Vision; 14 (B) Getty Images; 15 (R) Getty Images; 16 Getty Images. Scott Foresman/Dorling Kindersley would also like to thank: Opener: (C) ©Jerry Young/DK Images; 12 (BC) ©Jerry Young/DK Images; 15 (BC) ©Jerry Young/DK Images. Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson. ISBN: 0-328-13986-6 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 13986_01-04_CVR_FSD.indd Cover213986_01-04_CVR_FSD.indd Cover2 5/12/05 1:34:50 PM5/12/05 1:34:50 PM . for insects to live. Many kinds of insect-eating birds live in this forest. Many of the birds migrate to warmer areas in winter. Other animals are adapted to the cold winters. Some of the small. coats, and they hunt other animals even in very cold weather. The dormouse becomes fat in the summer and autumn, and hibernates in the winter. 11 13986_05-20_FSD.indd 1113986_05-20_FSD.indd 11. group of individuals of the same species that live in one area. The frogs in the picture make up a population. The dragonfl ies are another population. If there were two kinds of frogs, they would