Genre Comprehension Skill Text Features Science Content Nonfiction Put Things in Order Captions Labels Glossary Life Cycles Scott Foresman Science 1.4 ì<(sk$m)=bdheec< +^-Ä-U-Ä-U ISBN 0-328-13744-8
Vocabulary larva life cycle pupa seed coat seedling tadpole Extended Vocabulary down fledge hatch nest nocturnal owlet by Jessica Quilty 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). 5 (T) Roger Tidman/Corbis. Unless otherwise acknowledged, all photographs are the copyright of Dorling Kindersley, a division of Pearson. ISBN: 0-328-13744-8 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
What You Already Know Plants and animals change as they grow. These changes are called life cycles. Different living things have different life cycles. A frog begins as an egg. A tadpole hatches out of the egg. The tadpole grows to be a frog. Butterflies change and grow too. They start as an egg. A larva, or caterpillar, hatches from the egg. It looks very different from an adult butterfly. Next the larva changes in a hard cover. It is then a pupa. The pupa is a butterfly when it comes out of the cover. This butterfly has just come out of its hard cover. Plants change and grow. Many plants begin as seeds. Seed coats are hard covers that keep seeds safe. Seedlings grow from seeds. These young plants can then grow flowers, stems, and leaves. Trees are plants. Some trees have flowers. Some trees have cones. Trees grow and change. Just like other living things, owls have life cycles. Owls change and grow in many ways. You are now going to read about some of the ways owls change and grow. Barn owl 2 3
Finding a Nest An owl needs a good nest so it can lay eggs. Different owls find nests in different places. Barn owls do not build their own nests. They use nests they find. Owl eggs Barn owls use nests in caves and in trees. They will also nest in the roofs of buildings. Owl nests protect eggs. They help to keep eggs safe from other animals. They also help keep owls, eggs, and babies warm. 4 5
Hatching Barn owls wait for their eggs to hatch. Mother owls sit on the eggs. The eggs need to stay warm. After about thirty days an egg begins to hatch. Barn owls lay one egg at a time. They may wait one day to lay another egg. The eggs hatch in order. Baby owls are called owlets. Crack by crack they make their way out of their eggs. The owlets are very small. They have down. Down is soft feathers. This down goes away as they grow. The owlet breaks the egg. It starts to come out. Slowly, the owlet comes out. 6 7
Growing Fast Owlets go through many changes. Their down falls off after a week. They then grow new down. This new down is a thick, heavy covering. It protects the owlets for about seven weeks. One-week-old owl Three-week-old owl Owlets have a lot of growing to do. They are always hungry! Their parents are very busy hunting for food to feed them. Owlets start becoming tall and strong when they are about three or four weeks old. 8 9
Getting Big The owlets are much heavier and much bigger at six weeks old. They are almost as big as they will get. But they are not ready to leave the nest. The young owls try to fly and hunt on their own. Six-week-old owl When they are about seven weeks old, the owlets fledge. This means they grow the adult feathers they need to fly. Now the owlets are big and strong. They are almost ready to leave their nests and see the world on their own! An eight-week-old owl is almost ready to fly away. Eight-week-old owl 10 11
Young Adult After barn owls grow their adult feathers, they have grown big and strong. Now they are ready to fly! The owls begin by taking short trips away from their nest. At nine weeks old they are able to stay away for more time. Owls fly away from and then back to their nests. Ten-week-old owl Barn owls are nocturnal, which means they hunt at night. When the owls are old enough, they hunt for food all through the night. When they are about a year old, the owls will begin looking for their own nests. They might lay their own eggs! 12 13
From Egg to Owl The barn owl life cycle begins with an egg. After about one month in the eggs, the baby owls, called owlets, hatch. Once they hatch, they grow very fast! They get bigger and stronger. The owlets have down. Their down changes. Soon they grow their flying feathers. They are grown owls when they are twelve weeks old. Then they are ready to leave the nest and begin their nighttime adventures! Just hatched One week old Three weeks old Six weeks old Eight weeks old Ten weeks old Twelve weeks old 14 15
Glossary down soft animal feathers fledge to grow feathers for flying What did you learn? 1. What is an owlet? 2. How old are owls when they are ready to fly? hatch nest nocturnal owlet to come out of an egg a home for animals that is made of plant and animal parts active at night a young owl 3. Owls lay eggs in nests. Write to tell the places their nests can be. Use words from the book as you write. 4. Put Things in Order Name some of the changes owls go through in their life cycle. Describe these changes in the order that they happen. 16