Make a Model Before Reading Sc ie nc e e nc ie Sc After Reading Life at the Make a diorama of the Arctic ecosystem. A diorama is a three-dimensional model. Poles Find pictures of Arctic plants and animals and their habitats. Read about the Arctic ecosystem in other books. Find materials that would best show this ecosystem. You might use a cardboard box, construction paper, cotton balls, paint, modeling clay, and plastic wrap. Make a KWL Chart Before you read, make a KWL chart on your own paper like the one below. Look at the pictures in this book. Read the headings. Tell what you think the book is about. Write what you know about ecosystems under the K. Write what you want to know under the W. K Genre Nonfiction Comprehension Skill Main Idea and Details Text Features Captions W L Science Content Ecosystems Labels Glossary After you read the book, finish the KWL chart. Write what you learned about ecosystems under the L. Interactive Science 3 Write labels for the living things in your model. Reading Support Tell your class about your model. by Kristin Cashore 0000c1_SCI13_LVR3_0328729353 1 12/20/11 3:11 PM
Before Reading Make a KWL Chart Before you read, make a KWL chart on your own paper like the one below. Look at the pictures in this book. Read the headings. Tell what you think the book is about. Write what you know about ecosystems under the K. Write what you want to know under the W. K W L After you read the book, finish the KWL chart. Write what you learned about ecosystems under the L.
During Reading population producer población consumer productor herbivore consumidor carnivore herbivore prey carnívoro predator presa decomposer predador descompondeor
During Reading Do you understand? Write or draw your answers on your own paper. 1. Draw a globe like this one. Add lines for labels. Write these labels in the correct places: North Pole, South Pole, Antarctic, Arctic. 2. How is a polar bear adapted to its environment? 3. What kind of consumer is a caribou? 4. Write About Science Explain how penguin mothers and fathers care for their eggs. Include details from the book.
Life at the Poles by Kristin Cashore Glenview, Illinois Boston, Massachusetts Chandler, Arizona Upper Saddle River, New Jersey Photographs 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. Unless otherwise acknowledged, all photographs are the copyright of Dorling Kindersley, a division of Pearson. Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd) Cover: (T) Getty Images, (B) Jupiterimages/Getty Images/Thinkstock 1 (C) Andy Rouse/NHPA Limited; 4 (B) Sharon K. Andrews/Shutterstock, (C) Vladimir Melnik/Fotolia; 5 (BR) by Alla/ Shutterstock; 6 (B) Jupiterimages/Getty Images/Thinkstock; 7 (B) Konrad Reszka/Fotolia, (T) Rolf Langohr/Fotolia; 8 (C) Pete Oxford/Nature Picture Library, (Bkgrd) Shutterstock; 10 (B) Thinkstock; 11 (BR) Shutterstock; 12 (L) Shutterstock; 13 (T) Fritz Polking/Peter Arnold Images/PhotoLibrary Group, Inc.; 15 (B) Getty Images, (TR) Shutterstock; 18 (B) melissaf84/shutterstock; 19 (T) Thinkstock; 21 (B) Fotolia, (T) Shutterstock; 23 (B) coastasd68/shutterstock; 24 (TR) Thinkstock; 26 (Bkgrd) PiLensPhoto/Fotolia; 27 (B) Jan Will/Fotolia; 28 (B) Alexander/Fotolia, (T) Roger Asbury/Fotolia; 30 (BL) Lars Johansson/Fotolia; 31 (Bkgrd) Fabrice Beauchene/Fotolia; FP2 (L) Pete Oxford/Nature Picture Library, (R) Rolf Langohr/Fotolia, (C) Sharon K. Andrews/Shutterstock, (TL) Thinkstock; FP3 (B) coastasd68/shutterstock; FP5 (B) Getty Images; FP6 (B) Fritz Polking/Peter Arnold Images/ PhotoLibrary Group, Inc. Copyright 2013 Pearson Education, Inc., or its affiliates. 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 or by any means, electronic, mechanical, photocopying, recording, or likewise. For information regarding permissions, write to Pearson Curriculum Group Rights & Permissions, One Lake Street, Upper Saddle River, New Jersey 07458. Pearson is a trademark, in the U.S. and/or other countries, of Pearson Education, Inc., or its affiliates. ISBN-13: 978-0-328-72935-7 ISBN-10: 0-328-72935-3 1 2 3 4 5 6 7 8 9 10 V0FL 16 15 14 13 12
What are ecosystems? Every living thing has its own environment. A living thing s environment is everything that surrounds it. An environment has living parts. It has nonliving parts. The living parts include plants, animals, and other living things. The nonliving parts include sunlight, air, water, and soil. The living and nonliving parts act together, or interact. These interacting parts together make up an ecosystem. Earth contains many different ecosystems. Deserts, grasslands, and forests are some of Earth s ecosystems. This book will focus on the coldest ecosystems the ecosystems near Earth s poles. Groups Within Ecosystems Arctic wolves live in the Arctic. All living things of the same kind that live in a place at the same time are a population. A group of arctic wolves make up a population. Arctic wolves hunt caribou. Caribou eat plants that grow in the short arctic summer. All the populations that live together in the same place make up a community. The wolves, caribou, and plants are part of a community. Populations in a community depend on each other. Living and nonliving things interact in this pond ecosystem. Arctic wolf 2 3
Energy in Ecosystems Plants make their own food. A living thing that makes its own food is a producer. Producers use energy from sunlight to make food. They change matter from the air and soil into sugar. Many living things cannot make their own food. They must get energy from food that they eat. A living thing that eats food is a consumer. Arctic Poppy Arctic plants are producers that make their own food. Animals are called consumers because they must consume food. There are three kinds of consumers. An herbivore eats only plants. A carnivore eats only animals. The Arctic wolf is a carnivore. They eat caribou. They eat musk oxen and Arctic hares too. An omnivore eats both plants and animals. All three types of consumers can be found in polar ecosystems. Caribou are herbivores. They eat plants for energy to live and grow. Arctic ground squirrels are omnivores. They eat plants. They eat insects. They eat other small animals too. 4 5
Food Chains Organisms in an ecosystem depend on one another. Energy passes from one organism to another. Energy passes to living things through food chains. Food chains are groups of producers and consumers that interact. A consumer eats a producer. The producer passes energy to the consumer. That consumer may become prey for another consumer. An animal that is hunted by others for food is prey. Prey passes energy onto a predator. A predator is a consumer that hunts other animals. This relationship is similar in any ecosystem on Earth. Fungi Fungi are decomposers. Plants and animals die. They decay when they die. Decomposers are organisms that help break down dead plants and animals. Decomposers turn once-living things into nutrients for the soil. Many decomposers are too small to be seen with the naked eye. Producers, consumers, and decomposers make energy flow through an ecosystem. The Arctic fox is the predator. The Arctic hare is its prey. 6 7
The Polar Regions Have you ever spun a globe? Do you remember the North and South Poles? The Arctic is the area at the top of the Earth, around the North Pole. It is mostly frozen water. This water is called the Arctic Ocean. The Antarctic is the area at the bottom of the Earth, around the South Pole. Most of the Antarctic is taken up by a frozen land mass called Antarctica. The Antarctic Ocean surrounds Antarctica. Polar bears live in the Arctic. They are predators. They are carnivores. These carnivores hunt over a huge area for seals to eat. Map of the Poles The geographic North Pole is the Earth s northernmost point. The geographic South Pole is the Earth s southernmost point. North Pole South Pole Both the Arctic and the Antarctic have very long, very cold winters. Polar winters are dark, without sunlight. Polar summers are very brief. It is always light, and temperatures rise a little. The polar regions may seem empty. But some animals live their whole lives there. Other animals come to feed during the summer. Even plants are part of these delicate polar ecosystems. Penguins inhabit Antarctic lands and waters. 8 9
The Arctic contains rolling plains called tundra. Tundra is especially common in Arctic regions that border the Arctic Ocean, such as Greenland, parts of Siberia, and northeastern Canada. Permafrost lies beneath the tundra surface. This is soil that has remained frozen for a very long time. Permafrost lies under about one-fifth of Earth s land, including much of the Arctic. During the summer season, the tundra surface above the permafrost becomes moist and marshy, creating wetlands in some areas. Moss, low shrubs, and flowering plants thrive during the tundra summer. Lichens grow on rocks and are widespread. Arctic plants survive almost anything. Antarctica is incredibly isolated. The world s stormiest ocean, the cold Southern Ocean, surrounds it on all sides. Antarctica s climate is harsh, with little precipitation. Scientists consider it the coldest desert on Earth! Lichens, mosses, and algae make up most of the Antarctic s producers. Summer waters are just warm enough for algae to grow and reproduce. Tiny, shrimp-like animals called krill feed on the algae. The krill population increases throughout the Antarctic summer. Krill swarms can cover as much as 520 square kilometers. Whales and birds arrive to eat krill. There are few producers in the Antarctic, but life could not exist without them! It is summer on the tundra, and this Arctic fox s coat has changed color. The rosebay willowherb can be found on the Arctic tundra. Antarctic lichens and mosses on rocks 10 11
Polar Bears The polar bears of the Arctic are the world s largest land predators. An adult male polar bear can weigh up to fifteen hundred pounds! Polar bears search for food on land and in the sea. They cover an enormous territory while searching for the seals that they eat. Polar bears are excellent swimmers and divers. They can swim for hours without rest. Their webbed forepaws help them to swim. Their blubber allows them to float. Polar bears blend into their white landscape. Snow Dens Polar bear cubs are born in snow dens during November and December. The cubs stay in their dens for three months. Their mother protects and feeds them. The cubs in this picture are sheltered from the wind and hidden from predators. They stay warm by curling into a ball. Polar bears are well adapted to their cold environment. The polar bear s white color blends in with the snow, so it can sneak up on prey. Fur and blubber retain heat, which keeps it warm. 12 13
Penguins Penguins live in the Southern Hemisphere. They are flightless birds. Instead of flying, they slide along the ice and swim. Penguins can dive very deep and swim very fast. Their diet includes fish and krill. Antarctic penguins range in height from about twenty inches to more than three feet. Their feathers are thick and waterproof. In addition, penguins have a thick layer of blubber. Penguins breed in huge colonies. Right after laying her egg, the mother emperor penguin goes to sea to feed. The father balances the egg on his feet, covering it with a warm flap of skin. Keeping Warm Penguin chicks sometimes huddle together to protect themselves from the severe temperatures. The father penguin stands in this position for two months, protecting the egg. The mother returns when the chick hatches. She feeds the chick regurgitated fish. Then the father goes to the sea to eat. Penguins cannot fly, but they are excellent divers and swimmers. Penguins are southern birds. They are never found in the Arctic. 14 15
Arctic Foxes The Arctic fox lives in the Arctic tundra. It has a double layer of fur, small ears, and short legs. Its thick foot-hair keeps it warm and helps it grip the ice. The fox sheds its thick, white fur in the summer. In summer, it has a thinner, brownish-gray coat. The Arctic fox is an omnivore. It eats almost anything. It specializes in catching rodents. It listens for movement below the snow. It jumps up and down when it hears a rodent. It breaks through the snow to catch its prey. Sometimes there are too few rodents to eat. Then the Arctic fox feeds on animal remains left behind by polar bears. The Arctic fox sheds its heavy winter coat during the summer. In the summer, Arctic foxes hunt alone and cover a small territory. They live in dens built into hills, cliffs, or riverbanks. Arctic foxes often take over abandoned squirrel burrows and enlarge them to meet their needs. In winter, they must travel much farther in search of prey. Arctic foxes sleep in snow tunnels during winter, and live and hunt together in family groups. The female Arctic fox gives birth to an average of seven pups. Both parents help raise them. The pups leave the den by their third month. Life in the Arctic is hard. Few Arctic foxes live past a year. The fox s winter coat is heavy and warm. 16 17
Whales The largest animals in the world include whales. Blue whales can be one hundred feet long! Whales are mammals, which means they must rise to the surface of the water to breathe. When they breathe, they push air through blowholes in the tops of their heads. When a whale exhales, it releases a spray of water through its blowhole. Whales have thick layers of blubber that keep them warm. Many types of whales migrate to the poles during summer to feed on the rich sea life. Toothed whales eat fish, octopus, squid, and other sea animals. The humpback whale sings many different songs. Beluga whales migrate in groups called pods. Other whales have baleen instead of teeth. Baleen looks like a brush with wide, flat bristles. Baleen strains krill and other small sea creatures into the whale s mouth. Bowheads, belugas, and narwhals all travel to the Arctic to feed. The bowhead is a baleen whale with a mouth shaped like a bow. Belugas and narwhals are both toothed whales. Male narwhals have a long tusk, like a unicorn. Baleen whales like the blue, fin, and humpback all migrate to the Antarctic. Toothed whales such as the orca whale and the sperm whale also swim the Antarctic seas. The orca whale eats penguins and seals. The sperm whale dives to below three thousand feet in search of squid. 18 19
Seals Seals are excellent swimmers and divers. Their diet includes fish, squid, and crustaceans. Like whales, seals are mammals. They can stay under water for a very long time before surfacing for air. Blubber and a thick layer of fur keep seals warm. Arctic seals, such as harp, hooded, and ringed seals, migrate in search of food and breeding grounds. Ringed seals are a polar bear s usual meal. Polar bears, arctic foxes, toothed whales, and sharks all hunt Arctic seals. Arctic seals live a dangerous life! Ice Holes Seals create breathing holes in the ice by chewing with their teeth, scratching with their claws, and bashing with their heads. Like Arctic seals, Antarctic seals travel in search of food and good breeding grounds. They have been known to visit the islands and continents close to Antarctica. Some important Antarctic seals include the leopard, Weddell, and crabeater seals. Like Arctic seals, the seals of the Antarctic are hunted by both sharks and toothed whales. young ringed seal crabeater seal 20 21
Birds Both the Arctic and the Antarctic are hosts to large populations of birds. The snowy owl lives year-round on the tundra grasslands. Its white winter coat turns a spotted brown during summer. It has excellent sight and hearing. Snowy owls like to swoop down silently to catch rodents. Unlike the snowy owl, the Arctic tern migrates more than twenty thousand miles every year! Arctic terns form communities of about fifty birds. Arctic tern Arctic terns rarely stop flying. They swoop down from the sky to catch fish and flying insects. Most albatrosses live in the Antarctic, but some species are found in the Arctic. The albatross is one of the largest flying birds in the world. It spends most of its life at sea but returns to land in the summer to breed. The auk belongs to a family of Arctic seabirds that includes puffins and razorbills. Auks and penguins look very similar. Unlike penguins, however, auks live in the Arctic and can fly. Auks are also very good swimmers. They snatch small fish, crustaceans, and mollusks from the water. The wingspan of a snowy owl extends up to five feet across. Auks can fly very fast, despite their short wings. 22 23
Caribou Caribou are large mammals. They range across the Arctic tundra. Both male and female caribou grow antlers. Male caribou are called bulls. Their antlers can grow to be four feet across. The bull uses his antlers to attract female caribou and fight other bulls. It only takes newborn caribou about an hour and a half to learn how to run! Soon after it is born, a caribou is running with the herds. Caribou Moss Caribou moss is a lichen. It is the caribou s most important winter food. Caribou smell caribou moss through the snow. They dig down deep to get to it. Newborn caribou learn to walk and run almost immediately so that they can join the migrating herds. Caribou populations migrate great distances across the tundra. They search for good grazing land. Caribou are herbivores. They eat grasses and flowering plants in the spring and summer. They survive on lichens in the winter. Caribou hooves are shaped perfectly for digging in snow. Their special hairs trap air and keep them warm. Caribou are very strong swimmers. They can paddle across rivers and in the cold Arctic Ocean. 24 25
Natural Threats Fire, flood, and disease affect species near the poles. These threats weaken small populations. The species are already trying to survive in a difficult environment. Climate changes have caused the Arctic to become drier and warmer. This dryness has caused more lightning. Lightning strikes can cause fires. Animals that survive a fire may not find the food they need to live. In 2007, a large area of land caught fire on the North Slope in Alaska. Many birds have their young in the Arctic. They migrate to other areas for winter. Migrating arctic shorebirds have spread several diseases to other bird populations. The shorebirds also can get diseases from other birds in their winter homes. The birds spread these diseases to others when they return to the Arctic. Populations are also at risk from diseases carried by people. Many Emperor penguins near a scientific base have died. They had an illness. Humans doing research in Antarctica probably brought the disease. Emperor Penguins Scientists in Antarctica are studying the health of penguin populations. Warmer temperatures can dry out plants in the Artic. Dry plants can easily catch fire. 26 27
Human Threats Human activities may change the climate near the poles. Carbon dioxide and other gases are increasing in the atmosphere. This might cause air temperatures to rise. Carbon dioxide is one greenhouse gas. Greenhouse gases trap heat in the atmosphere. This trapped heat warms the climate near the poles. This warming causes more ice to melt each summer. Melting ice causes sea levels to rise. Rising sea levels produce flooding near the poles. Ice that once protected a shoreline may melt. The land can wash away. Greater summer ice melt threatens polar bears. The Trans-Alaska Pipeline is over 1200 kilometers long. Hundreds of animals live near or fly over the pipeline. People s search for resources can also threaten polar environments. Oil is an important energy resource. People drill for oil in Alaska. They have built long pipelines to carry oil to tankers. Some areas of the pipeline are raised to allow animals to migrate. Unfortunately, oil tankers and pipelines can leak. Oil that spills from tankers pollutes the ocean. It can wash up on land. The oil from a damaged pipeline can cover plants and animals. It can soak the thin soil. 28 29
Keeping Polar Ecosystems Healthy People can help keep polar ecosystems healthy. Conserving resources is one way. Conserve means to use less. People can conserve oil. People can conserve coal. Instead, people can use solar power and wind. Burning less coal and oil reduces the greenhouse gases in the air. Another way to help polar populations is to leave their habitats alone. If people use alternate energy sources, fewer pipelines are needed. Fewer pipelines mean less chance of an oil spill. The environment that populations live in would be safer. People can limit contact with polar environments. More people visiting these environments bring more risk of disease. It also brings other problems. For these and other reasons, 48 countries have agreed to set Antarctica aside as a scientific preserve. Countries have agreed to conduct scientific research in Antarctica. Arctic Caribou The Arctic National Wildlife Refuge protects hundreds of species. 30 31
Glossary carnivore an animal that eats only other animals for food community all the populations in an area consumer a living thing that eats other living things for food decomposer an organism that breaks down onceliving matter ecosystem herbivore omnivore population predator prey producer interacting living and nonliving parts in an area an animal that eats only plants an animal that eats plants and animals all the living things of the same kind that live in the same place at the same time an animal that hunts other animals for food any animal that is hunted by others for food a living thing that makes its own food 32
After Reading Did you understand? Write your answers on your own paper. 1. What is a population? 2. How can an animal such as a seal be both predator and prey? 3. How do living things like fungi interact with other living things in polar environments? 4. How does conserving energy resources help save environments near the poles?
After Reading Make a Model Make a diorama of the Arctic ecosystem. A diorama is a three-dimensional model. Find pictures of Arctic plants and animals and their habitats. Read about the Arctic ecosystem in other books. Find materials that would best show this ecosystem. You might use a cardboard box, construction paper, cotton balls, paint, modeling clay, and plastic wrap. Write labels for the living things in your model. Tell your class about your model.
Clues to Arctic Life Read about plants and animals of the Arctic and Antarctic. Write clues describing each plant and animal. Your clues can be about color, height, weight, or whether the plant or animal lives in the Arctic or in the Antarctic. Read your clues to your classmates, and see if they can identify what plant or animal you are describing.
Make a Model Before Reading Sc ie nc e e nc ie Sc After Reading Life at the Make a diorama of the Arctic ecosystem. A diorama is a three-dimensional model. Poles Find pictures of Arctic plants and animals and their habitats. Read about the Arctic ecosystem in other books. Find materials that would best show this ecosystem. You might use a cardboard box, construction paper, cotton balls, paint, modeling clay, and plastic wrap. Make a KWL Chart Before you read, make a KWL chart on your own paper like the one below. Look at the pictures in this book. Read the headings. Tell what you think the book is about. Write what you know about ecosystems under the K. Write what you want to know under the W. K Genre Nonfiction Comprehension Skill Main Idea and Details Text Features Captions W L Science Content Ecosystems Labels Glossary After you read the book, finish the KWL chart. Write what you learned about ecosystems under the L. Interactive Science 3 Write labels for the living things in your model. Reading Support Tell your class about your model. by Kristin Cashore 0000c1_SCI13_LVR3_0328729353 1 12/20/11 3:11 PM