By Jocelyn Cranefield Mheducation.Com/Prek-12
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Expository Text STRATEGIES & SKILLS Comprehension ELL Vocabulary Strategy: Ask and Answer efficiently, extend, features, Questions survive Skill: Cause and Effect Content Standards Vocabulary Science adaptations, agile, caches, Life Science dormant, forage, frigid, hibernate, insulates Word Count: 1,425** Photography Credit: MICHAEL NICHOLS/National Geographic Creative **The total word count is based on words in the running text and headings only. Numerals and words in captions, labels, diagrams, charts, and sidebars are not included. by Jocelyn Cranefield mheducation.com/prek-12 Copyright © 2014 McGraw-Hill Education All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of McGraw-Hill Education, including, but not limited to, network storage or transmission, or broadcast for distance learning. Send all inquiries to: McGraw-Hill Education Two Penn Plaza New York, New York 10121 ISBN: 978-0-02-118774-4 MHID: 0-02-118774-6 PAIRED Printed in the United States of America. Why Bat Flies at Night READ 8 9 10 11 12 QVS 22 21 20 19 18 E Genre Expository Text Essential Question Introduction How are living things adapted to their environment? There are caves all over the world. Many caves extend deep below the surface of Earth. At first, a cave looks like a dark, empty space. If you shine a flashlight inside a cave, you probably will not see anything. But if you go inside the cave, Cave there are many living things. Caves can be on the coast, in a forest, or under mineral CREATURES formation the desert. Caves are made by Jocelyn Cranefield out of limestone, marble, or lava from volcanoes. Some caves have beautiful mineral formations. Other caves are Introduction ................................ 2 full of smelly, poisonous Chapter 1 gases. Every cave is a home From the Entrance to the Twilight Zone ..... 4 for animals. Chapter 2 Dark and Surprising Places ................. 10 Conclusion.................................. 16 Respond to Reading ........................ 18 PAIRED READ Why Bat Flies at Night ........... 19 Glossary ................................... 22 Index ...................................... 23 Lechuguilla Cave in New Mexico has Focus on Science ................. 24 beautiful mineral formations. 2 Creative Geographic MICHAEL NICHOLS/National Some animals are visitors to caves. Some animals From the Entrance live in caves all the time. Many animals have Chapter ONE to the Twilight Zone adaptations to live in caves. Adaptations are features that help living things survive. Some animals stay near the cave entrance for shelter or to sleep. There, it is warm in winter and cool in summer. CAVES OF ALL SIZES These animals are called Explorers have found more than 50,000 caves in the world. Some caves have a single tunnel. Other caves trogloxenes, or cave visitors. have many interconnected tunnels. The deepest cave is They go outside the cave the Krubera Cave. It is about 7,188 feet deep. Compare bat to get food. Bats, skunks, the depth of the Krubera Cave with the heights of tall raccoons, and snakes are buildings, below. The longest cave is the Mammoth Cave system in Kentucky. It extends for more than 350 miles trogloxenes. underground. The Mexican free-tailed bat The Krubera Cave is a trogloxene. It is nocturnal. CAVE During the day, this bat roosts CAVE LOCATIONS DEPTH sunset 0 ft in colonies on cave roofs. At dusk, it leaves the cave to 1,000 ft catch insects. 2,000 ft 3,000 ft 4,000 ft BUILDING HEIGHT 2,723 ft 5,000 ft Bats come out of 2,000 ft the cave at night 6,000 ft to hunt. 1,000 ft 7,000 ft Krubera Cave, 7,188 feet deep 3 4 All Rights Reserved. ©Corbis. COMP/ILLUS: I don’t know what amendments are planned to this diagram. My input is this: currently there is a lot shown at very tiny size. It would be better to include less information and to enlarge any type Mexican free-tailed bats, and most other bats, have an The glowworm turns off its light when it hears a noise. adaptation called echolocation to find their way in the dark. The bat makes high-pitched squeaking sounds, then listens for an echo. The echo helps the bat figure out where things are. abdomen light In some places, bats The twilight zone is located deeper inside the cave. hibernate in caves during the It is cool and damp. Green plants can’t grow because winter. They don’t sleep all ear there is very little light. Many creatures that live here winter. They wake up from their are called troglophiles, or cave lovers. Troglophiles can dormant state every 15 to 30 The Virginia spend their whole lives in caves, but they can also days for a short time. A place big-eared bat survive outside. Some types of spiders, earthworms, where a bat hibernates is called hibernates in the beetles, frogs, and crickets are troglophiles. a hibernaculum. Hellhole caverns in West Virginia. The dark twilight zone has little food. The animals During winter, it is warmer can’t see well, so they use other senses. They use inside the cave than outside. sound and touch to find food and get around. The The cave insulates animals from Bears enter a deep animals have adaptations to live in the twilight zone. the cold. sleep in winter. Some scientists think Glowworms are troglophiles. Their adaptation is the this is a type of hibernation. ability to light up their abdomen to attract prey. The glowworm spins a web, then lights up its abdomen. Don’t is a negative The glowworm caches insects in the web until the contraction. What Language glowworm is ready to eat. Detective words make up the contraction? In Other Words move from one place to another. En español, get around quiere decir moverse. (t)U.S. Fish & Wildlife Service/Craig Stihler, (b)Juniors Bildarchiv/R304/Alamy Stock Photo Stock (b)Juniors Bildarchiv/R304/Alamy Service/Craig Stihler, Wildlife & Fish (t)U.S. 5 6 Photo Stock blickwinkel/Hauke/Alamy Plants can’t grow in a dark cave, so what do animals eat? Rain and underground streams bring The New Zealand cave weta twigs, leaves, seeds, insects, and plant-based nutrients is also a troglophile. It is a kind into the cave. The droppings of bats, cave crickets, of cricket that lives on cave and other animals contain plant material. These are roofs. It has antennae that are sources of food for animals in the cave. about seven times longer than its body. The antennae help Molds, fungi, and bacteria break down the plant the weta to move and to feel material so that tiny, microscopic animals can eat it. around for food. The agile weta The larger cave animals eat the microscopic animals. Then other cave predators eat the larger animals. can jump more than 6 feet! antennae The New Zealand cave weta has long legs so it can leap away from danger. CAVE LIONS Bones of lions were discovered in caves in France and were named cave lions. ADAPTING TO SILENCE Scientists believe that the cave lions lived between The African cave cricket communicates secretly without 12,000 and 40,000 years making any sound. It uses wings to send out tiny puffs ago. The lions were about of air, called vortices. Other cave crickets can feel these 25 percent bigger than the vortices, but predators cannot feel the vortices. lions today. The cave lions probably didn’t live in caves most of the time. hind leg Animal bones can be preserved in caves for a long Scientists have learned time because conditions inside about the cave lions from wings caves do not often change. very old bones. STOP AND CHECK Why do animals need to adapt to live in caves? (t)Heather Angel/Alamy Stock Photo, (b)Premaphotos/Alamy Stock Photo Stock (b)Premaphotos/Alamy Photo, Stock Angel/Alamy (t)Heather 7 8 covenant/Shutterstock CAVE FOOD WEB In this food web, nutrients in guano, or bat droppings, and other materials are broken down and recycled by cave creatures and microscopic organisms. These Dark and creatures are eaten by larger predators. Chapter TWO Surprising Places Bats Frogs The dark zone is deep underground in the heart of a cave. There is no light, nor wind. No Small insects, such as mosquitoes, gnats, glowworms, crickets plants grow in the dark zone. Life in the Dark Zone Animals that live in the dark zone are called troglobites, or cave Beetles Centipedes Spiders dwellers. They have adaptations such as small bodies, long limbs, This insect is a and long antennae. They have the Tiny insects, mites dipluran. It has ability to detect small vibrations no eyes or wings. Instead, it has or smells. These adaptations help long antennae the creatures move around and and two tails. Earthworms Fungi forage for food efficiently. Cave silt Bacteria Mold Guano Spores In Other Words far inside. En español, in the heart of quiere decir en lo más profundo. Matter carried Minerals by water 9 10 Source/Getty Images Fenolio/Science Dante pincer This pseudoscorpion has very long pincers, but it has no eyes. Many troglobites have different adaptations than the animals that live above the ground. Animals that live in the dark zone have tiny eyes or no eyes at all because eyes are not useful in dark places. ENTRANCE ZONE Most animals that live above ground have a coloring in their skin called pigment. Pigment is an adaptation. It protects animals from the sun. In the dark zone, TROGLOXENES pigment is not useful. So some troglobites have nearly TWILIGHT ZONE see-through, or translucent, skin.