1、The C rcle of LifeCover,Robert Pickett/Corbis;3,(1r)Royalty-Free/Corbis;(c)Image Source/SuperStock;4,Hans Pfletschinger/Peter Arnold,Inc.;5,Cary Wolinsky/IPNS;6,Kris Timken/Blend Images/PictureQuest;7,Keren Su/Stone/Getty Images;8,James King-Holmes/Photo Researchers,Inc.;9,Stephen Dalton/Minden Pict
2、ures;10,Ronald Bosma/Foto Natura/Minden Pictures;11,Dr.John Cunningham/Visuals Unlimited;12,Tim Hall/Photodisc Green/Getty Images;13,Macduff Everton/Corbis;14,Tim Hall/Photodisc Green/Getty Images.Copyright by Harcourt,Inc.All rights reserved.No part of this publication may be reproduced or transmit
3、ted in any form or by any means,electronic or mechanical,including photocopy,recording,or any information storage and retrieval system,without permission in writing from the publisher.Requests for permission to make copies of any part of the work should be addressed to School Permissions and Copyrig
4、hts,Harcourt,Inc.,6277 Sea Harbor Drive,Orlando,Florida 328876777.Fax:407-345-2418.HARCOURT and the Harcourt Logo are trademarks of Harcourt,Inc.,registered in the United States of America and/or other jurisdictions.Printed in MexicoISBN 10:0-15-350288-6ISBN 13:978-0-15-350288-0Ordering OptionsISBN
5、10:0-15-349940-0(Grade 5 ELL Collection)ISBN 13:978-0-15-349940-1(Grade 5 ELL Collection)ISBN 10:0-15-357325-2(package of 5)ISBN 13:978-0-15-357325-5(package of 5)If you have received these materials as examination copies free of charge,Harcourt School Publishers retains title to the materials and t
6、hey may not be resold.Resale of examination copies is strictly prohibited and is illegal.Possession of this publication in print format does not entitle users to convert this publication,or any portion of it,into electronic format.1 2 3 4 5 6 7 8 9 10 126 12 11 10 09 08 07 06by Kristi McGeeRXENL08AR
7、D5E18_ELL.indd 111/20/06 4:36:54 PMRXENL08ARD5E18_ELL.indd 27/10/06 9:00:57 AMEverything goes through a growth process.Puppies,kittens,and human babies grow.They get older.They change along the way.Babies turn into children.Children turn into teenagers.Teenagers turn into adults.These are big change
8、s.However,these changes arent as big as the changes in the life of a silkworm.A silkworm changes from a tiny egg to a moth.There are four steps:egg,caterpillar,cocoon,and moth.3RXENL08ARD5E18_ELL.indd 37/10/06 9:03:10 AMSTEP 1:EggTotal Egg Time:1014 DaysThink of a chicken egg.The eggshell keeps the
9、chick safe while it grows.When it is ready,the chick breaks out of its shell.The silkworm does the same thing.The silkworm is much smaller than a chick,though.A silkworms egg is the size of a pinhead!The shell of the egg protects the growing worm.4RXENL08ARD5E18_ELL.indd 48/11/06 2:33:54 AM5A silkwo
10、rm moth lays hundreds of eggs.They are yellow.The eggs rest in cold temperatures.Then the eggs are warmed.Sometimes they get warm as spring comes.If the silkworms are raised by humans,people warm,or incubate,the eggs.Warming makes the eggs change color.They turn blue-gray.Then the eggs start to grow
11、.Two weeks later,tiny silkworms hatch from the eggs.RXENL08ARD5E18_ELL.indd 58/11/06 2:32:40 AMSTEP 2:CaterpillarTotal Caterpillar Time:27 Days A silkworm is very tiny when it hatches from the egg.It is a caterpillar,or worm.It is only about 1 or 2 millimeters(0.040.08 in.)long.Thats smaller than a
12、grain of rice.In the next twenty-seven days,the caterpillar grows to about 80 millimeters(3.15 in.).That is eighty times bigger than when it hatched!Imagine if humans grew that much.We would be over 100 feet(30.5 m)tall!Thats the size of a ten-story building!6RXENL08ARD5E18_ELL.indd 67/10/06 9:08:45
13、 AMThe caterpillar has to eat a lot to grow that much.The only things that the young caterpillars eat are mulberry leaves.The mulberry is a kind of bush or tree.The little caterpillars eat new leaves.The bigger caterpillars eat bigger leaves.If the caterpillars are being raised by people,they are fe
14、d special food if mulberry leaves are not available.7RXENL08ARD5E18_ELL.indd 77/10/06 9:09:24 AMThe caterpillar changes as it grows.In fact,it sheds its skin four times.This is called molting.Other animals molt,too.Have you ever seen a snakeskin?Snakes lose their skin just like silkworms.Even birds
15、molt.They dont lose skin.They lose feathers.Sometimes the caterpillars eat their own skin.What does a silkworm catepillar look like?It is gray in color.Its body is in segments,or parts.The head and first segment of a caterpillar can swell and look bigger.This helps scare off enemies.A full-grown cat
16、erpillar looks glossy,or shiny.It is full of silk.8RXENL08ARD5E18_ELL.indd 87/10/06 9:10:23 AMSTEP 3:CocoonTotal Cocoon Time:14 DaysBuilding a cocoon is hard work.The cocoon is made out of silk.The silk comes out of the caterpillar near its mouth.First,the caterpillar has to find a good place to bui
17、ld its cocoon.The cocoon will be held in place by silk.The caterpillar attaches the silk to a safe place.Then,the caterpillar starts making its cocoon.Each caterpillar has nearly 15 inches(38.1 cm)of silk inside its body!Thats a lot for a 3-inch(7.6 cm)caterpillar.9RXENL08ARD5E18_ELL.indd 98/11/06 2
18、:34:56 AMThe caterpillar moves its head back and forth to make the cocoon.The silkworm makes the cocoon in two or three days.Finally,the silkworm is closed inside the waterproof cocoon.Big changes take place inside the cocoon.The caterpillar molts one last time.Its body turns hard and brown.Then it
19、starts changing into a moth.10RXENL08ARD5E18_ELL.indd 107/10/06 9:12:28 AM11STEP 4:MothTotal Moth Time:57 DaysThe moth grows inside the cocoon.When the moth is ready to come out,it weakens the cocoon.The moth uses its saliva to do this.The moth comes out ready to lay eggs.Silkworm moths are about 2
20、inches(5.1 cm)wide.The moths are light tan or gray.They cannot fly or eat.Their mouths arent totally formed.The moths live for only a few days after laying eggs.Then the moths die.The silkworms life cycle begins again.Total Life Cycle of a Caterpillar:69 DaysRXENL08ARD5E18_ELL.indd 118/11/06 2:37:08
21、 AMAll About the SilkPeople dont make silk material from the silk of silkworms that live in the wild anymore.People raise the silkworms.The silkworms are fed.The cocoons are kept safe.When the moths are close to coming out,the best cocoons are chosen.Those cocoons are saved,and the moths from them a
22、re used to lay new eggs.The other cocoons are baked in an oven.The next step is the silk-making process.12RXENL08ARD5E18_ELL.indd 127/10/06 9:14:05 AMPeople only want the silk from the cocoons.The baked cocoons are placed in hot water.Then people use a brush to clean off the outside of each cocoon.A
23、t the same time they look for the beginnings of the long strings of silk.They are silk thread.13RXENL08ARD5E18_ELL.indd 137/10/06 9:14:43 AMSilk thread is used to make silk cloth.Silk cloth is used to make many things.Silk is usually expensive.It costs so much because of the work and time needed to
24、make silk.Also,a lot of silkworms are needed to make a small amount of silk.Would you believe over 600 cocoons are used to make one shirt?More than 100 cocoons are needed to make a necktie.The next time you go to the store,look for items that are made of silk.Think about all the work that went into
25、making each itemby both people and silkworms.14RXENL08ARD5E18_ELL.indd 147/10/06 9:15:15 AMWord Count:932Scaffolded Language DevelopmentUSING SEQUENCE WORDS Point out examples of the sequence words first,next,then,after that,and finally in the book.Tell students that next,then,and after that are use
26、d in similar ways to identify steps in the middle of a sequence.They are just used for variety in the text.Have students number the following sentences in the correct order on a separate sheet of paper and then rewrite the sentences in order,using the sequence words listed above.Silkworms hatch from
27、 the eggs.A moth comes out of the cocoon.The silkworms molt and turn into caterpillars.A caterpillar spins a cocoon.A moth lays thousands of eggs.ScienceCreating a Diagram Have students create a diagram of the silk worms life cycle and label the appropriate features and stages.School-Home Connection
28、 Experiencing Silk Have students share with family members the steps involved in making silk.Have them try to find any items made from silk in their homes.To the TeacherRXENL08ARD5E18_ELL.indd 158/11/06 2:37:55 AMRXENL08ARD5E18_ELL.indd 167/10/06 9:15:45 AMThe C rcle of LifeHarcourt LeveledReaders Online Database GRADE 5Lesson 18WORD COUNT932GENREExpository NonfictionLEVELELL9 780153 5028809 0 0 0 0ISBN-13:978-0-15-350288-0ISBN-10:0-15-350288-6by Kristi McGeeRXENL08ARD5E18_ELR_COV.indd 2-38/11/06 2:03:06 AM
