15 Invertebrates Compression guide: Chapter Planning Guide · 2013. 3. 4. · Section 4 Echinoderms •Describe the endoskeleton, nervous system, and water vascular system of echinoderms

OBJECTIVES LABS, DEMONSTRATIONS, AND ACTIVITIES TECHNOLOGY RESOURCES

Compression guide:To shorten instructionbecause of time limitations,omit Section 2.

InvertebratesChapter Planning Guide

Chapter Opener

OSP Lesson Plans (also in print) TR Bellringer Transparency*VID Lab Videos for Life ScienceCD Science Tutor

TE Group Activity Determining Symmetry, p. 380g TE Connection Activity Real World, p. 382g SE Connection to Environmental Science Threatened

Reefs, p. 383g TE Activity Observing Hydras, p. 383g TE Demonstration Stinging Cells, p. 384 ◆g

SE School-to-Home Activity A Walk in the Park,p. 385g

TE Connection Activity Real World, p. 385g SE Skills Practice Lab Soaking Sponges, p. 402 ◆g

CRF Datasheet for Chapter Lab*

Section 1 Simple Invertebrates• Describe the body plans, nervous systems, and guts

of invertebrates.• Explain how sponges get food.• Describe three cnidarian characteristics.• Describe the three kinds of flatworms.• Describe the body of a roundworm.

OSP Lesson Plans (also in print) TR Bellringer Transparency*CD Science Tutor

TE Group Activity Mollusk Menus, p. 388g TE Group Activity Earthworms in Action, p. 390g LB Inquiry Labs At a Snail’s Pace* ◆a

LB Labs You Can Eat Here’s Looking at You,Squid* ◆g

PACING • 45 min pp. 388–391Section 2 Mollusks and Annelid Worms• Explain how mollusks eat, control body functions, and

circulate blood.• Describe the four body parts that most mollusks have

in common.• Describe the three kinds of annelid worms.

OSP Lesson Plans (also in print) TR Bellringer Transparency* TR L53 The Stages of Complete

Metamorphosis* TR L54 Incomplete Metamorphosis* TE Internet Activity p. 394g

CRF SciLinks Activity*gCD Science Tutor

TE Connection Activity Math, p. 393a TE Activity Making Models, p. 394 ◆g

TE Group Activity, p. 394g SE Quick Lab Sticky Webs, p. 395g

CRF Datasheet for Quick Lab* TE Activity Insecticide Alternatives, p. 396a SE Skills Practice Lab The Cricket Caper, p. 781g

CRF Datasheet for LabBook*

PACING • 45 min pp. 392–397Section 3 Arthropods• List the four main characteristics of arthropods.• Describe the different body parts of the four kinds of

arthropods.• Describe the two types of metamorphosis in insects.

OSP Lesson Plans (also in print) TR Bellringer Transparency* TR L55 The Water Vascular System* TR LINK TOLINK TO EARTH SCIENCEEARTH SCIENCE E51 The Three

Groups of Marine Life*CD Science Tutor

TE Activity Sea Star Hypotheses, p. 398g SE Science in Action Math, Social Studies, and Language

Arts Activities, p. 408–409g LB Long-Term Projects & Research Ideas Creepy, Crawly

Food?a

PACING • 45 min pp. 398–401Section 4 Echinoderms• Describe the endoskeleton, nervous system, and

water vascular system of echinoderms.• Explain how an echinoderm’s body symmetry

changes with age.• Describe five classes of echinoderms.

OSP Parent Letter ■

CD Student Edition on CD-ROM CD Guided Reading Audio CD ■

TR Chapter Starter Transparency*VID Brain Food Video Quiz

SE Start-up Activity, p. 379gpp. 378–387PACING • 135 min

CRF Vocabulary Activity*g SE Chapter Review, pp. 404–405g

CRF Chapter Review* ■g

CRF Chapter Tests A* ■g, B*a, C*s SE Standardized Test Preparation, pp. 406–407g

CRF Standardized Test Preparation*gCRF Performance-Based Assessment*gOSP Test Generator, Test Item Listing

CHAPTER REVIEW, ASSESSMENT, ANDSTANDARDIZED TEST PREPARATION

Online and Technology Resources

Visit go.hrw.com foraccess to Holt OnlineLearning, or enter thekeyword HL7 Homefor a variety of freeonline resources.

This CD-ROM package includes:• Lab Materials QuickList Software• Holt Calendar Planner• Customizable Lesson Plans• Printable Worksheets

• ExamView® Test Generator• Interactive Teacher’s Edition• Holt PuzzlePro®

• Holt PowerPoint® Resources

PACING • 90 min

377A Chapter 15 • Invertebrates

15

STANDARDS CORRELATION SKILLS DEVELOPMENT RESOURCES SECTION REVIEW AND ASSESSMENT CORRELATIONS

CRF Directed Reading A* ■b, B*sIT Interactive Textbook* Struggling ReadersStruggling Readers

CRF Vocabulary and Section Summary* ■g

SE Reading Strategy Reading Organizer, p. 380g TE Inclusion Strategies, p. 381 SE Math Practice Several Sponges, p. 382g TE Support for English Language Learners, p. 382 TE Reading Strategy Mnemonics, p. 383b

CRF Reinforcement Worksheet Life Without a Backbone*b

SE Reading Checks, pp. 381, 382, 385, 386g TE Reteaching, p. 386b TE Quiz, p. 386g TE Homework, p. 386g TE Alternative Assessment, p. 387g SE Section Review,* p. 387 ■g

CRF Section Quiz* ■g

UCP 1, 4, 5; LS 1a, 1d, 1f, 2a,3a, 3c, 5a; Chapter Lab: UCP 3;SAI 1; LS 1a



SE Reading Strategy Discussion, p. 388g TE Support for English Language Learners, p. 389 TE Inclusion Strategies, p. 391

SE Reading Checks, pp. 389, 391g TE Reteaching, p. 390b TE Quiz, p. 390g TE Alternative Assessment, p. 390g SE Section Review,* p. 391 ■g


UCP 1, 2, 3, 5; LS 1a, 1d, 3a, 5a



SE Reading Strategy Prediction Guide, p. 392g TE Connection to Chemistry Chitin, p. 394g TE Support for English Language Learners, p. 395 MS Math Skills for Science Dividing Whole Numbers with

Long Division*g MS Math Skills for Science Checking Division with Multiplication*g

SE Reading Checks, pp. 393, 395, 397g TE Reteaching, p. 396b TE Quiz, p. 396g TE Alternative Assessment, p. 396g SE Section Review,* p. 397 ■g


UCP 2, 3, 5; SAI 2; LS 1a, 1d, 1f,5a; LabBook: SAI 1; LS 3c



SE Reading Strategy Paired Summarizing, p. 398g TE Connection to Earth Science Marine Life, p. 398g TE Reading Strategy Prediction Guide, p. 399g TE Support for English Language Learners, p. 399

CRF Reinforcement Worksheet Spineless Variety*bCRF Critical Thinking A New Form of Danger in the Deep*a

SE Reading Checks, pp. 399, 401g TE Reteaching, p. 400b TE Quiz, p. 400g TE Alternative Assessment, p. 400g SE Section Review,* p. 401 ■g


UCP 5; LS 1a, 1d, 3a, 5a

SE Pre-Reading Activity, p. 378gOSP Science Puzzlers, Twisters & Teasers*g

National ScienceEducation Standards

UCP 1; SAI 1; LS 5a

CRF Chapter Resource File SS Science Skills Worksheets IT Interactive TextbookOSP One-Stop Planner MS Math Skills for Science Worksheets * Also on One-Stop Planner

SE Student Edition LB Lab Bank CD CD or CD-ROM ◆ Requires advance prepTE Teacher Edition TR Transparencies VID Classroom Video/DVD ■ Also available in Spanish

KEY

Maintained by the NationalScience Teachers Association.See Chapter Enrichment pagesthat follow for a complete listof topics.

www.scilinks.orgCheck out Current Sciencearticles and activities byvisiting the HRW Web siteat go.hrw.com. Just typein the keyword HL5CS15T.

• Lab Videos demonstratethe chapter lab.

• Brain Food Video Quizzeshelp students review thechapter material.

ClassroomVideos

Holt Lab GeneratorCD-ROM

Search for any lab by topic, standard,difficulty level, or time. Edit any labto fit your needs, or create your ownlabs. Use the Lab Materials QuickListsoftware to customize your labmaterials list.

• Guided Reading Audio CD(Also in Spanish)

• Interactive Explorations• Virtual Investigations• Visual Concepts• Science Tutor

ClassroomCD-ROMs

Chapter 15 • Chapter Planning Guide 377B

Planning ResourcesTEST ITEM LISTINGPARENT LETTERLESSON PLANS

Visual ResourcesCHAPTER STARTER

TRANSPARENCYBELLRINGER

TRANSPARENCIES TEACHING TRANSPARENCIES

TEACHING TRANSPARENCIESCONCEPT MAPPING

TRANSPARENCY

TEST ITEM LISTING

Copyright © by Holt Rinehart and Winston All rights reserved

The World of ScienceMULTIPLE CHOICE

1. A limitation of models is thata. they are large enough to see.b. they do not act exactly like the things that they model.c. they are smaller than the things that they model.d. they model unfamiliar things.Answer: B Difficulty: I Section: 3 Objective: 2

2. The length 10 m is equal toa. 100 cm. c. 10,000 mm.b. 1,000 cm. d. Both (b) and (c)Answer: B Difficulty: I Section: 3 Objective: 2

3. To be valid, a hypothesis must bea. testable. c. made into a law.b. supported by evidence. d. Both (a) and (b)Answer: B Difficulty: I Section: 3 Objective: 2 1

4. The statement "Sheila has a stain on her shirt" is an example of a(n)a. law. c. observation.b. hypothesis. d. prediction.Answer: B Difficulty: I Section: 3 Objective: 2

5. A hypothesis is often developed out ofa. observations. c. laws.b. experiments. d. Both (a) and (b)Answer: B Difficulty: I Section: 3 Objective: 2

6. How many milliliters are in 3.5 kL?a. 3,500 mL c. 3,500, 000 mLb. 0.0035 mL d. 35,000 mLAnswer: B Difficulty: I Section: 3 Objective: 2

7. A map of Seattle is an example of aa. law. c. model.b. theory. d. unit.Answer: B Difficulty: I Section: 3 Objective: 2

8. A lab has the safety icons shown below. These icons mean that you should weara. only safety goggles. c. safety goggles and a lab apron.b. only a lab apron. d. safety goggles, a lab apron, and gloves.Answer: B Difficulty: I Section: 3 Objective: 2

9. The law of conservation of mass says the tot al mass before a chemical change isa. more than the total mass after the change.b. less than the total mass after the change.c. the same as the total mass after the change.d. not the same as the total mass after the change.Answer: B Difficulty: I Section: 3 Objective: 2

10. In which of the following areas might you find a geochemist at work?a. studying the chemistry of rocks c. studying fishesb. studying forestry d. studying the atmosphereAnswer: B Difficulty: I Section: 3 Objective: 2

TEACHER RESOURCE PAGE

Lesson Plan

Section: Waves

PacingRegular Schedule: with lab(s): 2 days without lab(s): 2 days

Block Schedule: with lab(s): 1 1/2 days without lab(s): 1 day

Objectives1. Relate the seven properties of life to a living organism.

2. Describe seven themes that can help you to organize what you learn aboutbiology.

3. Identify the tiny structures that make up all living organisms.

4. Differentiate between reproduction and heredity and between metabolismand homeostasis.

National Science Education Standards CoveredLSInter6: Cells have particular structures that underlie their functions.

LSMat1: Most cell functions involve chemical reactions.

LSBeh1:Cells store and use information to guide their functions.

UCP1:Cell functions are regulated.

SI1: Cells can differentiate and form complete multicellular organisms.

PS1: Species evolve over time.

ESS1: The great diversity of organisms is the result of more than 3.5 billion yearsof evolution.

ESS2: Natural selection and its evolutionary consequences provide a scientificexplanation for the fossil record of ancient life forms as well as for the strikingmolecular similarities observed among the diverse species of living organisms.

ST1: The millions of different species of plants, animals, and microorganismsthat live on Earth today are related by descent from common ancestors.

ST2: The energy for life primarily comes from the sun.

SPSP1: The complexity and organization of organisms accommodates the needfor obtaining, transforming, transporting, releasing, and eliminating the matterand energy used to sustain the organism.

SPSP6: As matter and energy flows through different levels of organization ofliving systems—cells, organs, communities—and between living systems and thephysical environment, chemical elements are recombined in different ways.

HNS1: Organisms have behavioral responses to internal changes and to externalstimuli.

This CD-ROM includes all of the resources shown here and the following time-saving tools:

• Lab Materials QuickList Software

• Customizable lesson plans

• Holt Calendar Planner

• The powerful ExamView ® Test Generator

Chapter Resources

Dear Parent,

Your son's or daughter's science class will soon begin exploring the chapter entitled “The

World of Physical Science.” In this chapter, students will learn about how the scientific

method applies to the world of physical science and the role of physical science in the

world. By the end of the chapter, students should demonstrate a clear understanding of the

chapter’s main ideas and be able to discuss the following topics:

1. physical science as the study of energy and matter (Section 1)

2. the role of physical science in the world around them (Section 1)

3. careers that rely on physical science (Section 1)

4. the steps used in the scientific method (Section 2)

5. examples of technology (Section 2)

6. how the scientific method is used to answer questions and solve problems (Section 2)

7. how our knowledge of science changes over time (Section 2)

8. how models represent real objects or systems (Section 3)

9. examples of different ways models are used in science (Section 3)

10. the importance of the International System of Units (Section 4)

11. the appropriate units to use for particular measurements (Section 4)

12. how area and density are derived quantities (Section 4)

Questions to Ask Along the Way

You can help your son or daughter learn about these topics by asking interesting questions

such as the following:

• What are some surprising careers that use physical science?

• What is a characteristic of a good hypothesis?

• When is it a good idea to use a model?

• Why do Americans measure things in terms of inches and yards instead of centimeters

and meters ?

377C Chapter 15 • Invertebrates

15

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Inverteb

ratesTEA

CHIN

G TR

AN

SPAR

ENCY

The Water Vascular System

Water enters the system

through holes in a flat plate on top of the sea star. This plate is called the

sieve plate.

a

Each tube foot connects to a bulb called an am

pu

lla (am

PU

HL uh). The am

pulla con-trols fluid pressure so that each tube foot can extend or retract, hang on or let go. A

s the tube feet and arm

move

together, the sea star moves

slowly along the sea floor.

e

The water flow

s through a tube to the

ring can

al around the mouth.

b

From the ring canal, the w

ater flows

intorad

ial canals in the arm

s.c

The radial canals connect to dozens of tiny suckers called

tub

e feet. Sea stars use tube feet to move

and to capture food. Oxygen enters and w

astes leave through the thin w

alls of the tube feet.

d


Explo

ring th

e Ocean

sTEA

CHIN

G TR

AN

SPAR

ENCY

The Three Groups of Marine Life

Plankton, nekton, and benthos are the three groups of organism

s that live in the ocean.

Zooplankton

Phytoplankton

Nekton

Benthos

Chapter: Exploring the Oceans

such assuch assuch as

earthworms

cnidarians

can have

include

which may be

radial

Invertebrates CONCEPT MAPPING TRANSPARENCY


Use the following terms to complete the concept map below:cnidarians, symmetry, invertebrates, mollusks, annelid worms, snails,bilateral, sponges, coral, asymmetry

Invertebrates CHAPTER STARTER

In 1995, researchers in Germany made a computerchip that could send signals to a single nerve cellin a living leech. Even more amazing, the leech’snerve cell could send signals back to the computerchip. What is so amazing about having a “mindlink” with a leech? The answer may surprise you.

In the United States alone, accidents resultin more than 10,000 spinal-cord injuries ayear. In severe cases, a person can lose mus-cle control, particularly in the arms and legs.But what does this have to do with leeches?

Giant leeches from South America, likethe one shown here on the scientist’s arm,have only a few nerve cells. By studyingleech nerves, biologists are learning how tocommunicate directly with nerve cells.

The scientists hope that communicating withleech nerves using a computer chip will oneday help them communicate with humannerve cells. In the future, people withspinal-cord injuries may be able to usecomputers to communicate with thenerve cells in their body and move theirmuscles.

Scientists still have a lot to learn, but who would have expected sucha promising breakthrough with ananimal that doesn’t even have abackbone? In this chapter, youwill learn about many spinelesscritters, the invertebrates.


Strange but True! Invertebrates BELLRINGER TRANSPARENCY


Section: Simple InvertebratesThink of all the beautiful or interesting invertebratesthat you have heard of, such as jellyfish, butterflies,beetles, earthworms, sea shells, and sea stars. Then describe your favorite invertebrate in yourscience journal. What special features does yourfavorite invertebrate have that will help it survive in its environment?

Section: Mollusks and Annelid WormsUnscramble the following words:glussisalnssdusqiklomssul

Write a sentence in your science journal using eachword. Your sentences should describe where andwhen you might find each organism.


Inverteb

ratesTEA

CHIN

G TR

AN

SPAR

ENCY

The Stages of Complete M

etamorphosis

aA

n adult lays eggs. An

embryo form

s inside each egg.

bA

larva hatches from the egg. B

ut-terfly and m

oth larvae are called cat-erpillars. The caterpillar eats leaves and grow

s rapidly. As the caterpillar

grows, it sheds its outer layer several

times. This process is called m

olting.

cA

fter its final molt, the cater-

pillar makes a chrysalis and

becomes a p

up

a. The pupal stage m

ay last a few days or

several months. D

uring this stage, the insect is inactive.

dA

dult body parts replace the larval body parts. The ad

ult splits its

chrysalis. eThe adult butterfly pum

ps blood into its wings

until they are full-sized. The butterfly is now

strong enough to fly.

Incomplete MetamorphosisInvertebrates TEACHING TRANSPARENCY


Adult

Eggs

Nymph

Nymph

Nymph

SAMPLE SAMPLE SAMPLE

Meeting Individual Needs

Review and Assessments

Labs and Activities

DIRECTED READING A VOCABULARY ACTIVITY REINFORCEMENT

INQUIRY LABSDATASHEETS FOR

QUICKLABSDATASHEETS FOR

QUICK LABS

STANDARDIZED TEST PREPARATIONCHAPTER TEST BCHAPTER REVIEWSECTION QUIZ

SCILINKS ACTIVITY

MARINE ECOSYSTEMS

Go to www.scilinks.com. To find links relatedto marine ecosystems, type in the keywordHL5490. Then, use the links to answer thefollowing questions about marine ecosys-tems.

1. What percentage of the Earth’s surface iscovered by water?

2. What percentage of the Earth’s water is found in the oceans?

3. What is the largest animal on Earth?

4. Describe an ocean animal.

Name Class Date

SciLinks ActivityActivity

Developed and maintained by theNational Science Teachers Association

Topic: Reproductive SystemIrregularitiesSciLinks code: HL5490


Name Class Date

Vocabulary ActivityActivity

Getting the Dirt on the SoilAfter you finish reading Chapter: [Unique Title], try this puzzle! Use the clues belowto unscramble the vocabulary words. Write your answer in the space provided.

1. the breakdown of rock intosmaller and smaller pieces:AWERIGNETH

2. layer of rock lying beneath soil:CROKDEB

3. type of crop that is plantedbetween harvests to reduce soilerosion: CROVE

4. action of rocks and sedimentscraping against each other andwearing away exposed surfaces:SABRONIA

5. a mixture of small mineral frag-ments and organic matter: LISO

6. rock that is a source of soil:PRATEN CORK

7. type of reaction that occurs whenoxygen combines with iron toform rust: oxidation

8. type of weathering caused byphysical means: CLEMANIACH

9. the chemical breakdown of rocksand minerals into new substances: CAMILCHETHEARIGWEN

10. layers of soil, to a geologist:SNORHIZO

11. the uppermost layer of soil:SPOTOIL

12. process in which rainwater car-ries dissolved substances fromthe uppermost layers of soil to thebottom layers: HELANCIG

13. small particles of decayed plantand animal material in soil:MUUSH

14. the process in which wind, water,or ice moves soil from one location to another: ROOSINE

15. the methods humans use to takecare of soil:OSIL VASETONRICON

LONG-TERM PROJECTS & RESEARCH IDEAS LABS YOU CAN EAT

VOCABULARY AND SECTION SUMMARY


Section: EnergIn the space provided, write the letter of the description that best matches theterm or phrase.

______ 1. building molecules that can be used asan energy source. or breaking down moleculesin which energy is stored

______ 2. the process by which light energy is convertedto chemical energy

______ 3. an organism that uses sunlight or inorganicsubstances to make organic compounds

______ 4. an organism that uses sunlight or inorganicsubstances to make organic compounds

______ 5. an organism that consumes food to get energy

______ 6. the process of getting energy from food

In the space provided, write the letter of the term or phrase that best completeseach statement or best answers each question.

Name Class Date

Section QuizAssessment

a. photosynthesis

b. autotroph

c. heterotroph

d. cellular respiration

e. metabolism

f. cellular respiration

______ 7. Which of the following mostclosely resembles cellularrespiration?a. warm water moving

through copper pipesb. people movimg alomg a

escalatorc. mixing different foods in

a blenderd. logs burning in a fire

______ 8. An organism’s reproductivecells, such as sperm or eggcells, are called?a. genesb. chromosomesc. gamates.d. zygotes.

______ 9. An organism’s reproductivecells, such as sperm or eggcells, are called?a. genesb. chromosomesc. gamates.d. zygotes.

______10. Which of the following mostclosely resembles cellularrespiration?a. warm water moving

through copper pipesb. people movimg alomg a

escalatorc. mixing different foods in

a blenderd.

logs burning in a fire


Section: ExploringTHAT’S SCIENCE!

1. How did James Czarnowski get his idea for the penguin boat, Proteus?Explain.

2. What is unusual about the way that Proteus moves through the water?

MATTER + AIR ➔ PHYSICAL SCIENCE

3. What do air, a ball, and a cheetah have in common?

4. What is one question you will answer as you explore physical science?

5. Chemistry and physics are both fields of . Chemists

study the different forms of and how they interact.

and how it affects are

studied in physics.

Identify the field of physical science to which each of the following descriptionsbelongs by writing physics or chemistry in the space provided.

_______________________ 6. how a compass works

_______________________ 7. why water boils at 100°C

_______________________ 8. how chlorine and sodium combine to form table salt

_______________________ 9. why you move to the right when the car you are inturns left

Directed Reading A

Name Class Date

Skills Worksheet

DIRECTED READING B

Section: ExploringTHAT’S SCIENCE!

1. How did James Czarnowski get his idea for the penguin boat, Proteus?Explain.

2. What is unusual about the way that Proteus moves through the water?

MATTER + AIR ➔ PHYSICAL SCIENCE

3. What do air, a ball, and a cheetah have in common?

Directed Reading B

Name Class Date

Skills Worksheet

Section: UniqueVOCABULARY

In your own words, write a definition of the following term in the space provided.

1. scientific method

2. technology

3. observation

Name Class Date

Vocabulary & NotesSkills Worksheet

Name Class Date

ReinforcementSkills Worksheet

The Plane TruthComplete this worksheet after you finish reading the Section: [Unique SectionTitle]

You plan to enter a paper airplane contest sponsoredby Talkin’ Physical Science magazine. The personwhose airplane flies the farthest wins a lifetime sub-scription to the magazine! The week before the con-test, you watch an airplane landing at a nearbyairport. You notice that the wings of the airplane haveflaps, as shown in the illustration at right. The paperairplanes you’ve been testing do not have wing flaps.What question would you ask yourself based on these observations? Write yourquestion in the space below for “State the problem.” Then tell how you could usethe other steps in the scientific method to investigate the problem.

1. State the problem.

2. Form a hypothesis.

3. Test the hypothesis.

4. Analyze the results.

5. Draw conclusions.

Flaps


CRITICAL THINKING

A Solar Solution

Name Class Date

Critical Thinking Skills Worksheet

Joseph D. Burns

Inventors’ Advisory Consultants

Portland, OR 97201

Dear Mr. Burns,I’ve got this great idea for a new product called the BlissHeater. It’s a portable, solar-powered space heater. The heater’s design includes these features:•T

he heater will be as longas an adult’s arm and aswide as a

packing box.

•T

he heater will have aglass top set at an angleto catch the sun’s rays.

•T

he inside of the heaterwill be dark colored toabsorb solar heat.If you think my idea will work, I will make the Bliss

Heaters right away without wasting time and money on test-ing and making models. Please write back soon with youropinion.

SECTION REVIEW

Section: UniqueKEY TERMS

1. What do paleontologist study?

2. How does a trace fossil differ from petrified wood?

3. Define fossil.

UNDERSTANDING KEY IDEAS

Name Class Date

Section ReviewSkills Worksheet


[UniqueMULTIPLE CHOICE


______ 1. Surface currents are formed by a. the moon’s gravity. c. wind.b. the sun’s gravity. d. increased water density.

______ 2. When waves come near the shore, a. they speed up. c. their wavelength increases.b. they maintain their speed. d. their wave height increases.

______ 3. Longshore currents transport sediment a . out to the open ocean. c. only during low tide.b. along the shore. d. only during high tide.

______ 4. Which of the following does NOT control surface currents?a. global wind c. Coriolis effectb. tides d. continental deflections

______ 5. Whitecaps break a. in the surf. c. in the open ocean.b. in the breaker zone. d. as their wavelength increases.

______ 6. Most ocean waves are formed by a . earthquakes. c. landsides.b. wind. d. impacts by cosmic bodies.

______ 7. Which factor controls surface currents? a. global winds c. continental deflectionb. the Coriolis effect d. all of the above

______ 8. Streamlike movments of ocean water far below the surface arecalleda. jet currents c. surface currents.b. Coriolis currents. d. deep currents.

______ 9. When the sunlit part of the moon that can be seen from Earthgrows larger, it is a. waxing. c. in the new moon phase.b. waning. d. in the full moon phase.

______10. The Milky Way is thought to be a. an elliptical galaxy. c. a spiral galaxy.

Name Class Date

Chapter Test BAssessment


READING

Read the passages below. Then, read each question that follows the passage.Decide which is the best answer to each question.

Passage 1 adventurous summer camp in the world. Billy can’twait to head for the outdoors. Billy checked the recommendedsupply list: light, summer clothes; sunscreen; rain gear; heavy,down-filled jacket; ski mask; and thick gloves. Wait a minute! Billythought he was traveling to only one destination, so why does heneed to bring such a wide variety of clothes? On further investiga-tion, Billy learns that the brochure advertises the opportunity to“climb the biomes of the world in just three days.” The destinationis Africa’s tallest mountain, Kilimanjaro.

______ 1. The word destination in this passage means A camp B vacation.C place. D mountain.

______ 2. Which of the following is a FACT in the passage? F People ski on Kilimanjaro.G Kilimanjaro is Africa’s tallest mountain.H It rains a lot on Kilimanjaro.J The summers are cold on Kilimanjaro.

______ 3. Billy wondered if the camp was advertising only one destination afterhe read the brochure, which said thatA the camp was the most adventurous summer camp in the world. B he would need light, summer clothes and sunscreen.C he would need light, summer clothes and a heavy, down-filled

jacket.D the summers are cold on Kilimanjaro.

Name Class Date

Standardized Test PreparationAssessment

PERFORMANCE-BASEDASSESSMENT

OBJECTIVEDetermine which factors cause some sugar shapes to break down faster than others.

KNOW THE SCORE!As you work through the activity, keep in mind that you will be earning a gradefor the following:

• how you form and test the hypothesis (30%)

• the quality of your analysis (40%)

• the clarity of your conclusions (30%)

ASK A QUESTIONSWhy do some sugar shapes erode more rapidly than others?

MATERIALS AND EQUIPMENT

Name Class Date

Performanced-Based AssessmentAssessment SKILL BUILDER

Using Scientific Methods

• 1 regular sugar cube • 90 mL of waterCopyright © by Holt, Rinehart and Winston. All rights reserved.

USING VOCABULARY

1. Define biome in your own words.

2. Describe the characteristics of a savanna and a desert.

3. Identify the relationship between tundra and permafrost.

4. Compare the open-water zone and the deep-water zone.

5. Use each of the following terms in an original sentence: plankton, littoralzone, and estuary.

6. Describe how marshes and swamps differ.

Name Class Date

Chapter ReviewSkills Worksheet

SCIENCE PUZZLERS, TWISTERS & TEASERS

CHAPTER TEST A






______ 4. Which of the following does NOT control surface currents?a global wind c Coriolis effect

Name Class Date

Chapter Test AAssessment

CHAPTER TEST C






______ 4. Which of the following does NOT control surface currents?a global wind c Coriolis effect

Name Class Date

Chapter Test CAssessment

For a preview of available worksheets covering math and science skills, see pages T26–T33. All of these resources are also on the One-Stop Planner®.

Chapter 15 • Chapter Resources 377D

Creepy, Crawly Food?

Name _______________________________________________ Date ________________ Class______________

SCIENCE PUZZLERS, TWISTERS & TEASERS15

Invertebrates

CHAPTER

Odd One Out1. For each group of terms, circle the one that doesn’t belong and

explain why not.a. earthworm, bristle worm, roundworm, leech

b. dog, sponge, planarian, human

c. lobster, squid, crab, pillbug

Bugs for Dinner?1. Research several cultures in which insects are part of peo-

ple’s regular diet. Why do they eat insects? How are theinsects prepared? What is their nutritional value? Discussyour findings in a report, and include at least two recipesthat contain insects as ingredients.

Research Ideas2. What does a mollusk have to do with photography? For

centuries, people have made products from mollusks.Pearls and mother-of-pearl are used in jewelry, and octo-puses release a black fluid that was once used to make ink.Discover the connections between mollusks and photo-graphy, and then research at least nine other molluskproducts. Make a poster display of your findings, andinclude samples, photos, or illustrations of the products.

3. The Great Barrier Reef, off the coast of Australia, supportsan incredible variety of marine life. It takes an incrediblenumber of coral skeletons, and sometimes millions ofyears, to build a coral reef. Find out how coral reefs areformed and why they are endangered. Present yourresearch in the form of a news article.

4. Most people try to avoid leeches, little wormlike creaturesthat suck blood. But did you know that leeches were usedto treat illnesses in the eighteenth and nineteenth cen-turies? Use library resources to find out how and whyleeches were used and how they are being used today.

Write a report about your findings.

5. If a scorpion stung you, would you know what todo? Research how the sting or bite of an arachnid,such as a scorpion or spider, affects the humanbody. How dangerous are these animals to humans?

What do they use their poison for? Find out whatyou should do if you are bitten, and write a

safety brochure outlining your findings.

How about having ants for lunch? Or maybe you prefer friedgrasshoppers for dinner? Although insects may not be youridea of a great meal, they are an important food source inmany parts of the world. Insect larvae, locusts, crickets,termites, and grasshoppers are just a few of the manyinsects that are eaten by humans. Dig in!

Name ___________________________________________________ Date _________________ Class _____________

PROJECT

STUDENT WORKSHEET15

Creepy, Crawly Food?

LIF

E S

CIE

NC

E

▼▼▼

STUDENT WORKSHEET

LAB

7

Name Date Class

LIF

E S

CIE

NC

E

▼▼▼

In Jules Verne’s classic science-fiction novel, 20,000 Leagues Under the Sea, the he-roes battle a deadly giant squid that threatens to crush the hull of a submarine.Although giant squids do exist, most of us have only encountered their smaller,more timid relatives. Yet even the smaller squid looks like the stuff of science fic-tion. The top of the squid’s head is actually a combined body-tail unit called amantle. The head has two large eyes and is surrounded by two long tentacles andeight arms with rows of round suckers underneath. Underneath the head is asmall opening to the funnel. The squid forces a jet of water through the funnelto propel itself backward or forward. Two fins are attached to the tail end of thesquid to help it steer. Although the squid doesn’t have a backbone, it does havea hard internal structure called a pen.

Now you can take a closer look at the unusual features of a squid.

Here’s Looking at You, Squid!

ObjectiveTo identify a number of structures and their functions in asquid, an aquatic invertebrate

Propel Yourself into Squid Dissection1. Your teacher will provide you with a squid. Lay the squid

flat on the plate, and examine it closely. Use the diagram be-low to help you identify the external parts of the squid.

MATERIALS

• squid• paper plate• magnifying glass• dissection knife• paper towels

Fin

Anteriorsurface

Eye

Arms

Tentacle

Ventral

Dorsal

Posteriorsurface

Funnel(siphon) Aquiferous

pore

Ventral

Dorsal

Dear Professor Sloe:

We would like to send a group of snails to outer space on the next shuttlemission. During a month-long study, these snails will be subject to fluctuationsin gravity, light, and temperature. To ensure the safety of the snails while inspace, we will need you to conduct a study in advance to learn about the snails’performance under various conditions. If theresults conclude that a space missionwith snails is possible, a representativewill visit you to collect the most respon-sive of your snail candidates. Please re-port your results to me as soon as possible.Thank you for your cooperation.

Sincerely,

Dr. C. StarsDirector of Zoological StudiesAstroPet Project

STUDENT WORKSHEET

LAB

5

LIF

E S

CIE

NC

E

▼▼▼

Name Date Class

Ask a QuestionHow do snails respond to different stimuli?

Make a Prediction1. How will the slope of the glass affect the distance a snail

travels?

Conduct an Experiment2. Tape one side of a picture frame to a table. Place the frame

flat on the table, as shown below. Label the tape “Start.”

MATERIALS

• 20 � 20 cm pictureframe

• masking tape• live snail• watch or clock that

indicates seconds• washable marker• metric ruler• paper towels• books• protractor• magnifying glass• tub of warm water• tub of ice water• cardboard• table lamp

At a Snail’s Pace

Copyright © by Holt, Rinehart and Winston. All rights reserved.Copyright © by Holt, Rinehart and Winston. All rights reserved.


Name Class Date

Reaction to StressQuick Lab DATASHEET FOR QUICK LAB

BackgroundThe graph below illustrates changes that occur in the membrane potential of aneuron during an action potential. Use the graph to answer the followingquestions. Refer to Figure 3 as needed.

Analysis1. Determine about how long an action potential lasts.

2. State whether voltage-gated sodium, chanels are open or closed at point A.

3. State whether voltage-gated potassium channels are open or closed atpoint B.

4. Critical Thinking Recognizing Relationships What causes the menberneotential to become less negative at point A?

5. Critical Thinking Recognizing Relationships What causes the membranepotential to become more negative at point B?


Answer here.

Answer here.

Answer here.

Answer here.

Answer here.

Using Scientific Methods

GENERAL

GENERAL

GENERALGENERAL

GENERAL

GENERAL

GENERAL

GENERAL

GENERAL

SPECIAL NEEDS

SPECIAL NEEDS GENERAL

GENERAL

SAMPLE

SAMPLE SAMPLE

SAMPLE SAMPLE

SAMPLE

SAMPLE

SAMPLE

SAMPLESAMPLE

SAMPLE

SAMPLE

SAMPLE

SAMPLE

SAMPLE

DATASHEETS FORCHAPTER LABS

Teacher’s NotesTIME REQUIRED

One 45-minute class period.

RATINGTeacher Prep–3Student Set-Up–2Concept Level–2Clean Up–2

MATERIALS

The materials listed on the student page are enough for a group of 4–5 students.Large, dried beans of any kind will work well in this exercise.

SAFETY CAUTION

Remind students to review all safety cautions and icons before beginning this labactivity.

Using Scientific MethodsSkills Practice Lab DATASHEET FOR CHAPTER LAB


1 2 3 4Easy Hard

Jason MarshMontevideo High

and Country School

Teacher’s NotesTIME REQUIRED

Does It All Add Up?Skills Practice Lab DATASHEET FOR LABBOOK LAB


SAMPLE

DATASHEETS FORLABBOOK

SAMPLE

SAMPLE

Chapter Enrichment

This Chapter Enrichment provides relevant and

interesting information to expand and enhance

your presentation of the chapter material.

Simple InvertebratesAristotle• The Greek philosopher Aristotle (384–322 BCE) was

particularly interested in marine invertebrates; he made detailed observations of sea stars, crustaceans, and mollusks—especially cuttlefish, which are related to squids.

Sponges are Animals• Sponges were not com-

pletely accepted as ani-mals until the early 1800s, when Scottish zoologist R. E. Grant conducted experiments in which he added fine, colored particles to the water around sponges. Grant watched undera microscope as the particles were taken into the sponges through microscopic pores and then “vomited forth” from the central cavity.

Is That a Fact!◆ Coral has a skeletal structure that is remarkably simi-

lar to human bone. Coral is now being used to speed up the growth of bone grafts.

◆ Tapeworms can reach enormous sizes. Some can grow to be longer than a school bus!

Medusa• The free-swimming form of a jellyfish has tentacles

and is called the medusa. It gets its name from Medusa, a character in Greek mythology. Medusa was a mon-ster whose long, curly “hair” was made of snakes.

Mollusks and Annelid WormsUseful, Edible Mollusks• More than any other inver-

tebrates, mollusks are consumed as food by people worldwide. Oysters, mussels, clams, snails, squids, and octopuses are just a few edible mollusks.

Is That a Fact!◆ Giant clams are the largest living bivalves. Shells of

the giant clam Tridacna gigas can be 1.5 m long and can have a mass of more than 225 kg.

Earth Movers• Charles Darwin (1809–1882) spent many years study-

ing earthworms and calculating their remarkable earth-moving abilities.

• Scientists estimate that the amount of soil brought to the surface by earthworms each year can be as much as 90 metric tons per hectare in temperate regions and considerably more in tropical regions. Earthworm activity aerates the soil and in some environments this activity improves growing conditions for plants.

Is That a Fact!◆ Australia is home to the world’s longest earthworms,

which can exceed 3 m in length.

Terrestrial Leeches• Most leeches are aquatic, but tropical rain forests are

home to terrestrial leeches. The body heat of mammals attracts these blood-sucking leeches. The leeches will quickly move over vegetation and converge on any unlucky animal that stands in one place for more than a few minutes.

377E Chapter 15 • Invertebrates

15

ArthropodsDiversity• Nearly 1 million species of arthropods have been identi-

fied. Scientists estimate that millions more are yet to be named. Arthropods are more densely and widely dis-tributed than members of any other animal group are.

• Arthropods are found in every imaginable type of environment, from moun-tain peaks to deep-sea trenches and from equato-rial rain forests to polar regions. Some arthropods are adapted for life on land, others for life in the air, and still others for life in salty, brackish, or fresh water.

Beetles• The order Coleoptera (meaning “sheathed wings”),

which contains beetles, fireflies, and weevils, is the largest order in the animal kingdom. There are more than 300,000 known species of beetles.

Is That a Fact!◆ All known species of spiders are predators. Their che-

licerae (anterior pair of appendages) end in fangs that inject venom that kills or paralyzes their prey. When a spider bites, it also pumps digestive enzymes into its victims. A spider can then suck up the resulting predi-gested “broth” from its prey.

EchinodermsHow Sea Stars Feed• The mouth of a sea star is located on the underside of its

body. A short esophagus leads to a large stomach that, in many species, can be pushed out, or everted, through the sea star’s mouth. When a sea star, such as Asterias,comes upon a clam, for example, it uses its tube feet and muscular arms to pull the clam’s shell apart just enough so that the sea star can push its everted stomach through the opening. The stomach then wraps around the soft parts of the clam’s body, and digestion begins.

Class Crinoidea• The echinoderm class Crinoidea is less familiar to

most people than the other classes in the phylum Echinodermata are. Crinoids include sea lilies and feather stars. Sea lilies have a stalked body topped by feathery arms that are used to snare small plankton from the water. Most sea lilies live in deep water. Feather stars are colorful, free-moving animals that have long, many-branched arms. Feather stars are common inhabitants of coral reefs.

Is That a Fact!◆ When disturbed, many types of sea cucumbers will

expel parts of their internal organs through the cloaca. This defense mechanism is quite effective in discouraging potential predators. The lost parts are quickly regenerated.

For background information about teaching strategies and

issues, refer to the Professional Reference for Teachers.

Topic: SpongesSciLinks code: HSM1443

Topic: RoundwormsSciLinks code: HSM1332

Topic: Mollusks and Annelid Worms

SciLinks code: HSM0986

Topic: ArthropodsSciLinks code: HSM0098

Topic: EchinodermsSciLinks code: HSM0458

Visit www.scilinks.org and enter the SciLinks code for more information about the topic listed.


SciLinks is maintained by the National Science Teachers Association to provide you and your students with interesting, up-to-date links that will enrich your classroom presentation of the chapter.

Chapter 15 • Chapter Enrichment 377F

Standards Correlations

National Science Education Standards

The following codes indicate the National Science EducationStandards that correlate to this chapter. The full text of thestandards is at the front of the book.

Chapter OpenerUCP 1; SAI 1; LS 5a

Section 1 Simple InvertebratesUCP 1, 4, 5; LS 1a, 1d, 1f, 2a, 3a, 3c, 5a

Section 2 Mollusks and Annelid WormsUCP 1, 2, 3, 5; LS 1a, 1d, 3a, 5a

Section 3 ArthropodsUCP 2, 3, 5; SAI 2; LS 1a, 1d, 1f, 5a; LabBook: SAI 1; LS 3c

Section 4 EchinodermsUCP 5; LS 1a, 1d, 3a, 5a

Chapter LabUCP 3; SAI 1; LS 1a

Chapter ReviewSAI 1; LS 1a, 5a

Science in ActionSAI 1, 2; ST 2; SPSP 5; LS 1a, 4d

OverviewTell students that this chapterwill help them learn about inver-tebrates, which are animalsthat do not have backbones.The chapter describes severalgroups of invertebrates, includingsimple invertebrates, mollusks,annelid worms, arthropods, andechinoderms.

Assessing PriorKnowledgeStudents should be familiarwith the following topics:

• cells

• classification

• animals and behavior

IdentifyingMisconceptionsAs students learn the material inthis chapter, some of them mayhave the mistaken impressionthat invertebrates—especiallyinsects—are creepy pests thatharm people. You may want toexplain to students that mostinvertebrates are harmless andmany are extremely helpful topeople. Few spiders, for exam-ple, can harm people. But manyspiders eat insects that are pests.Also, many invertebrates arebeautiful creatures, such asbutterflies, starfish, and mol-lusks that make elegant shells.Encourage students to observeinvertebrates that live nearbyso that students overcome suchmisconceptions.

15

PRE-READINGPRE-READING

Invertebrates

About the

No, this creature isn’t an alien! It’s a sea slug,a relative of garden slugs and snails. This seaslug lives in the cold Pacifi c Ocean, near thecoast of California. Its bright coloring comesfrom the food that the slug eats. This animaldoesn’t breathe with lungs. Instead, it bringsoxygen into its body through the orange clubson its back. Like all invertebrates, sea slugsdon’t have a backbone.

Tri-Fold Before youread the chapter, createthe FoldNote entitled “Tri-

Fold” described in the Study Skills sec-tion of the Appendix. Write what youknow about invertebrates in the columnlabeled “Know.” Then, write what youwant to know in the column labeled“Want.” As you readthe chapter, writewhat you learnabout invertebratesin the columnlabeled “Learn.”

SECTION

Invertebrates are animalsthat do not have backbones.

15

1 Simple Invertebrates . . . . . . . . 380

2 Mollusks and AnnelidWorms . . . . . . . . . . . . . . . . . . . . 388

3 Arthropods . . . . . . . . . . . . . . . . 392

4 Echinoderms. . . . . . . . . . . . . . . 398

378 Chapter 15 • Invertebrates

START-UPClassify It!Animals are classified according to their different traits. In this activity, you will classify invertebrates.

Procedure1. Look at the pictures that your teacher has pro-

vided. These animals do not have a backbone.

2. Which animals are the most alike? Organize them into groups according to their shared traits.

3. Decide which animals within each group are the most alike. Put these animals into smaller groups inside of their larger group.

4. Construct a table that organizes your classification groups.

Analysis1. What features did you use to classify the animals

into the larger groups? Explain why you think these features are the most important.

2. What features did you use to place the animals in smaller groups? Explain your reasoning.

3. Compare your table with those of your class-mates. What similarities or differences do you find?

Chapter 15 • Invertebtates 379

START-UPSTART-UP vvM A T E R I A L S

FOR EACH STUDENT• pictures of invertebrates

Teacher’s Notes: Provide each student with 6 to 12 pictures of invertebrates. Each student should receive some pictures of invertebrates that have unique features and some pictures of invertebrates that have common features.

Answers

1. Answers may vary according to the animal pictures provided to students. Students should explain the logic of their group-ings. Sample answer: I grouped animals by the number of their legs and wings.

2. Answers may vary according to the animal pictures provided to students. Students should explain the logic of their group-ings. Sample answer: I grouped animals by how many legs, antennae, wings, and eyes they have as well as by where they live and what their body shape is.

3. Answers may vary. Look for logical, well-reasoned answers. Students may find that not every-one used the same features to classify the animals.

Invertebrates CHAPTER STARTER

In 1995, researchers in Germany made a computerchip that could send signals to a single nerve cellin a living leech. Even more amazing, the leech’snerve cell could send signals back to the computerchip. What is so amazing about having a “mindlink” with a leech? The answer may surprise you.

In the United States alone, accidents resultin more than 10,000 spinal-cord injuries ayear. In severe cases, a person can lose mus-cle control, particularly in the arms and legs.But what does this have to do with leeches?

Giant leeches from South America, likethe one shown here on the scientist’s arm,have only a few nerve cells. By studyingleech nerves, biologists are learning how tocommunicate directly with nerve cells.

The scientists hope that communicating withleech nerves using a computer chip will oneday help them communicate with humannerve cells. In the future, people withspinal-cord injuries may be able to usecomputers to communicate with thenerve cells in their body and move theirmuscles.

Scientists still have a lot to learn, but who would have expected sucha promising breakthrough with ananimal that doesn’t even have abackbone? In this chapter, youwill learn about many spinelesscritters, the invertebrates.


Strange but True!

Chapter Starter TransparencyUse this transparency to help students begin thinking about why humans study invertebrates.

CHAPTER RESOURCESTechnology

Transparencies • Chapter Starter Transparency

Student Edition on CD-ROM

Guided Reading Audio CD • English or Spanish

Classroom Videos • Brain Food Video Quiz

Workbooks

Science Puzzlers, Twisters & Teasers • Invertebrates g

READINGSKILLS

READING STRATEGY

1 Simple InvertebratesHumans and snakes have them, but octopuses and butterfliesdon’t. What are they? Backbones!

Animals that don’t have backbones are called invertebratesinvertebrates(in VUHR tuh brits). They make up about 96% of all animalspecies. So far, more than 1 million invertebrates have beennamed. Most biologists think that millions more have notbeen identified yet.

Invertebrate CharacteristicsInvertebrates come in many different shapes and sizes. Grass-hoppers, clams, earthworms, and jellyfish are examples ofinvertebrates. They are all very different from each other. Someinvertebrates have heads, and others do not. Some invertebrateseat food through their mouths. Others absorb food particlesthrough their tissues. But all invertebrates are similar becausethey do not have backbones.

Invertebrates have three basic body plans, or types ofsymmetry. Symmetry can be bilateral (bie LAT uhr uhl) orradial (RAY dee uhl). Some animals have no symmetry atall. Animals that don’t have symmetry are asymmetrical(AY suh MEH tri kuhl). Most animals have bilateral symmetry.Figure 1 shows examples of each kind of symmetry.

Radial Symmetry AsymmetryBilateral Symmetry

This ant has bilateral symmetry.The two sides of its body mirror each other. On each side of its body, the ant has one eye, one antenna, and three legs.

This sea star has radial sym-metry. Its body is organized around the center, like spokes on a wheel.

This sponge is asymmetrical. You cannot draw a straight line to divide its body into two or more equal parts. Its body is not orga-nized around a center.

Animal Body PlansFigure 1

What You Will Learn

Describe the body plans, nervoussystems, and guts of invertebrates.Explain how sponges get food.Describe three cnidariancharacteristics.Describe the three kinds offlatworms.Describe the body of a roundworm.

Vocabularyinvertebrate gutganglion coelom

Reading Organizer As you readthis section, create an outline of thesection. Use the headings from thesection in your outline.

1

OverviewThis section introduces studentsto some simple invertebrates:sponges, cnidarians, flatworms,and roundworms. Students learnabout the different body plansand important characteristics ofthese animals.

BellringerHave students write downtheir answers to the followingquestions:

• What is an invertebrate? (ananimal that lacks a backbone)

• What is your favorite inverte-brate? (Answers may vary.)

• What special features helpyour favorite invertebrate sur-vive? (Answers may vary.)

GroupGroup vv -------gDetermining Symmetry Dividestudents into cooperative groupsof three or four. Give each groupa small, rectangular hand mirrorand copies of simple, top-viewdrawings of a butterfly and a seaurchin. Challenge students to usethe mirror to demonstrate thatthe butterfly has bilateral symme-try and that the sea urchin hasradial symmetry.l Kinesthetic ee

CHAPTER RESOURCES

Chapter Resource File

CRF • Lesson Plan• Directed Reading Ab• Directed Reading Bs

Technology

Transparencies• Bellringer

Workbooks

Interactive Textbook Struggling Readers Struggling Readers

CulturalAwarenessCulturalAwareness a

Spicule Strength The silica spiculesfrom many freshwater sponges are sharp,abrasive, and strong. In Russia, driedfreshwater sponges have long been usedto polish silver, brass, and other metals.People who live along the Amazon Riverin South America add sponge spicules toclay to strengthen the clay pots that theymake. Have students research other usesof spicules or whole sponges and createa poster based on their findings. l Visual


Neurons and GangliaAll animals except sponges have special tissues that make fibers called neurons. Neurons allow animals to sense their environ-ment. Neurons also carry messages around the body to control an animal’s actions. Simple invertebrates have neurons arranged in networks or in nerve cords. Nerve cords are packs of neurons that carry messages along a single path.

In some invertebrates, many nerve cells come together as ganglia (singular, ganglion). A ganglion (GANG glee uhn) is a concentrated mass of nerve cells. Each ganglion controls differ-ent parts of the body. Ganglia are connected by nerve cords. In complex invertebrates, ganglia are controlled by a brain. Thebrain is an organ that controls nerves throughout the body.

GutsAlmost all animals digest food in a gut. A gut is a pouch lined with cells that release chemicals that break down food into small particles. The cells in the gut then absorb the food particles. In complex animals, the gut is inside a coe-lom (SEE luhm). A coelom is the body cavity that surrounds the gut. The coelom contains many organs, such as the heart and lungs. But these organs are separated from the gut. This arrangement keeps gut movement from disturbing other body processes. Figure 2 shows an earthworm’s coelom.

✓Reading Check How is the coelom related to the gut? (See the Appendix for answers to Reading Checks.)

SpongesSponges are the simplest invertebrates. They are asymmetrical and have no tissues, gut, or neurons. Adult sponges move only millimeters per day—if they move at all. In fact, sponges were once thought to be plants! But sponges can’t make their own food. That’s one reason they are classified as animals. Figure 3shows a sponge.

GutCoelom

Figure 2 Earthworms have a fluid-filled coelom that contains the gut.

invertebrate an animal that does not have a backbone

ganglion a mass of nerve cells

gut the digestive tract

coelom a body cavity that contains the internal organs

Figure 3 Some sponges are brightly colored.

Using the Figure -----gMaking Sense of SymmetryHave students study the three invertebrates in Figure 1. Dis-cuss where these animals live and how they move through their environments. Tell stu-dents that being bilaterally symmetrical is an advantage for animals that travel through the environment and that being radially symmetrical is an advantage for animals that live attached to a substrate. Ask students to look at the organ-isms pictured in the figure and think of reasons why the state-ment about the advantages of different kinds of symmetry may be true.l Verbal ee

Answer to Reading Check

The coelom is the space in the body that surrounds the gut.

Discussion ----------------------------------g

Digestion Have students dis-cuss the advantages of having a central gut that is specialized for digestion. (Answers may include the following: In animals that have a coelom, powerful digestive enzymes are isolated from cells and tissues that those enzymes might harm. The delicate absorptive surface is pro-tected by being internalized. Also, the breakdown of food particles takes place more rapidly in a cen-tralized gut than it does in individual, unspecialized body cells. Finally, wastes are isolated from other parts of the body in animals that have a central gut.) l Verbal

• the human body (bilateral)

• ear (asymmetry)

• hand with fingers and thumb (asymmetry)

• eyeball (radial)

• foot with toes (asymmetry)

• thumb (bilateral)l Kinesthetic ee

StrategiesStrategiesINCLUSIONINCLUSION

• Visually Impaired• Developmentally DelayedSome students learn best when ideas are both concrete and personal. Make the meanings of the different symmetries both concrete and personal by having students label each of the following body parts as having bilateral symmetry, radial symmetry, or asymmetry:

Section 1 • Simple Invertebrates 381

Water carries food into the sponge throughpores. Inside the sponge, collar cellsremove food from the water. Thewater exits through an osculum.

Water flow

Collar cells linethe central cavityof a sponge.

Pore cells haveholes that letwater flow intothe sponge.

Osculum

How Do Sponges Eat?Sponges feed on tiny plants and animals. Because sponges can-not move in search of food and do not have a gut, they havea special way of getting food. A sponge sweeps water into itsbody through its pores. Pores are the holes on the outside ofa sponge’s body. Water flows into a cavity in the middle ofthe body, bringing oxygen and food. Special cells called collarcells line this cavity. Collar cells filter and digest food from thewater that enters the body. Water leaves the body through ahole at the top of the sponge. This hole is called an osculum(AHS kyoo luhm). Figure 4 shows this process.

✓Reading Check How does water enter a sponge’s body?

Body Part AbilitiesSponges have some unusual abilities. If you forced a sponge’sbody through a strainer, the separated cells could come backtogether and re-form into a new sponge. If part of a spongeis broken off, the missing part can regenerate, or grow back.And if a sponge is broken into pieces, or fragmented, newsponges may form from each fragment. Though sponges canuse regeneration as a form of reproduction, they also use sexualreproduction.

Pores

Several SpongesSuppose that a big spongebreaks into seven pieces.Each piece begins to growinto a new sponge. Then,each new sponge breaks intofive smaller pieces, and eachof these new pieces formsa new sponge. How manysponges would you have?

How Sponges EatFigure 4

CONNECTIONCONNECTION vvReal World ---------------------------------------------g

Helpful Sponges Sponges havefew predators. The sharp spic-ules and tough fibers in the bod-ies of sponges discourage fishand other aquatic organismsfrom eating sponges. Manysponges also produce toxicchemicals that deter predatorsand keep other sponges fromgrowing too close. A chemicalfrom a Caribbean sponge,Cryptotethya crypta, was oneof the first marine compoundsto be used in chemotherapy.Currently, many other com-pounds produced by sponges arebeing tested as anticancer andantiviral drugs. Have students usethe Internet to research othermodern uses for chemicals pro-duced by sponges. l Verbal

Answer to Math Practice

35 sponges


Water enters a sponge’s body through pores.Nearly all sponges are sessile—they liveattached to a surface and cannot movefrom place to place. Tethya seychellensis,a species that lives in the Red Sea, is anexception. Young sponges of this speciescan move very slowly—about 10 mm to15 mm a day—by extending long, stickyprojections from their body wall. Theprojections attach to the substrate andthen contract to pull the sponge forward.

SUPPORT FOR

English LanguageLearnersSponge Expansion As youdemonstrate sponge expan-sion, write important vocab-ulary on the board so you canreview concepts with students.Principal words will include:natural sponge, examine,sponging-fi ber network, absorb,swell, fi bers. Place a thin, dryslice of natural sponge under amicroscope, and allow stu-dents to examine the spong-ing-fiber network. Next, adda few drops of water to thesponge and have studentsexamine it again. Studentsshould be able to see clearlyhow the water is taken upby the fibers (the fibers willswell slightly) and taken intothe spaces between the fibers.Have students orally describewhat they saw using thevocabulary you wrote on theboard.l Visual/Verbal


Kinds of SpongesAll sponges live in water, and most live in the ocean. Asshown in Figure 5, sponges come in many different shapesand sizes. Most sponges have a skeleton made of small, hardfibers called spicules (SPIK YOOLZ). Some spicules are straight,some are curved, and others have complex star shapes. Asponge’s skeleton supports its body and helps protect it frompredators. Sponges are divided into groups according to theiroverall shape.

CnidariansDo you know anyone who has been stung by a jellyfish? It isa very painful experience! Jellyfish are members of a group ofinvertebrates that have stinging cells. Animals in this groupare called cnidarians (ni DER ee uhns).

Cnidarians are more complex than sponges. Cnidarianshave complex tissues and a gut for digesting food.They also have a simple network of nerve cells.Most cnidarians can move more quickly thansponges can. But some cnidarians do sharea characteristic with sponges. If these cni-darians are broken into smaller pieces,the pieces can form new cnidarians.

Two Body FormsA cnidarian body can have one of twoforms—the medusa or the polyp form. Thesebody forms are shown in Figure 6. Medusas swimthrough the water. Polyps usually attach to a surface.Some cnidarians change forms at different times in theirlives. But many cnidarians are polyps for their whole lives.

Figure 5 Sponges come in manyshapes and sizes.

Medusa

Polyp

Figure 6 Both the medusaand the polyp forms of ajellyfish have radial symmetry.

Threatened Reefs Coralreefs are home to many beau-tiful cnidarians. But livingcoral reefs are threatened byoverfishing, pollution, mining,coral harvesting, coastal devel-opment, and damage fromswimmers and boats. Scientistsare looking for ways to protectcoral reefs. One solution is toteach people not to touch orcollect living corals. Make aposter about how people canprotect coral reefs by leavingthem alone.

Crustacean-Eating SpongeA species discovered in theMediterranean Sea amazedmarine biologists and con-fused taxonomists. This spe-cies, called a carniveroussponge, resembles a spongeexcept for its feeding habits.A typical sponge is a filterfeeder, but the carnivoroussponge is not. The carnivo-rous sponge eats crustaceansby growing thin filamentsthat cover its prey. The preyis dissolved and digested bythe sponge in a matter ofdays. Because of this species,scientists are rethinking thedefinition of sponge.

READINGSTRATEGY ----------------------b

Mnemonics Write medusa andpolyp on the board. Point outthat medusa contains the letter dand that this form of a cnidarianhas tentacles that hang downfrom the animal’s body. Also,the word polyp contains the let-ter p, and this form of a cnidar-ian has tentacles that project upfrom the animal’s body. Studentscan use this idea to rememberthe body forms. l Verbal

vv--------------------------------------g

Observing Hydras Obtain live hydras andwater fleas (Daphnia) from a biological sup-ply house. Distribute the hydras in water-filled specimen dishes. Have pairs ofstudents study the hydras under a dissect-ing microscope. Add a few water fleas toeach dish, and have students observe howhydras use their tentacles to capture andsubdue prey. Encourage students to drawthe hydras and to record their observationsof how hydras move and manipulate cap-tured prey into their mouths. l Visual

The tentacles of some cnidarians cansting even if the tentacles are detachedfrom the body or if the animal is dead.Physalia, the Portuguese man-of-war, isa colonial cnidarian that often washesashore along temperate and tropicalbeaches. Barefoot beachgoers who stepon these stranded cnidarians know thatthe stinging cells can still fire even ifthe animals have been dead for days.


Stinging CellsAll cnidarians have tentacles covered with stinging cells. Whenan organism brushes against the tentacles, it activates hundredsof stinging cells. Each stinging cell uses water pressure to firea tiny, barbed spear into the organism. Figure 7 shows a sting-ing cell before and after firing. The tiny spears can release apainful—and sometimes paralyzing—poison into their targets.Cnidarians use their stinging cells to protect themselves andto catch food.

Kinds of CnidariansThere are three major classes of cnidarians: hydrozoans(HIE dro ZOH uhn), jellyfish, and sea anemones and corals.Figure 8 shows each kind of cnidarian. Hydrozoans are commoncnidarians that live in both freshwater and marine environ-ments. Most spend their entire lives as polyps. Jellyfish catchother invertebrates and fish in their tentacles. They spend mostof their lives as medusas. Sea anemones and corals spend theirlives as polyps. They are often brightly colored.

Most corals are small and live in colonies. Some corals buildhuge skeletons that are made of calcium carbonate. Each newgeneration of corals builds on top of the last generation. Overthousands of years, these tiny animals build massive under-water reefs. Coral reefs can be found in warm, tropical watersthroughout the world.

After FiringWhen the tiny spear is fired, the long, barbed strand ejects into the prey. Larger barbs also cover the base of the strand.

Before FiringCoiled inside each stinging cell is a tiny, barbed spear.

Figure 7 Each stinging cell contains a tiny spear.

Kinds of CnidariansFigure 8

Hydrozoan

Sea anemone

Jellyfish

Coral

Demonstration --------------gStinging Cells After studentshave studied Figure 7, performthe following demonstration.Invert the fingers of a rubberglove, and use duct tape toattach the top of the glovesecurely to the head of a waterfaucet. Tell students that theinverted fingers of the gloverepresent nematocysts coiledwithin stinging cells. Scientistshave discovered that nemato-cysts “fire” as a result of a sud-den change in water pressureinside stinging cells. When anematocyst is stimulated to dis-charge, the nematocyst mem-brane becomes highly permeableto water. As water rushes in,the sudden increase in waterpressure pushes the nematocystout with explosive force and turnsthe nematocyst inside out in theprocess. Demonstrate this phe-nomenon by briefly turning onthe faucet. The sudden pressureincrease will cause the invertedfingers of the rubber glove toevert quickly andforcefully. l Visual ee

Research -------------------------------------------gWriting Jellyfish Have students

research Aurelia, a genusof jellyfish. Then, have

students write a story in whichthey discuss how the jellyfishmove, what jellyfish eat, andhow jellyfish sense theirenvironment.l Verbal PORTFOLIO

Transparent Trappers Many jellyfishthat capture and eat small fish havetransparent or nearly transparent bodiesand long, trailing tentacles that arevery difficult to see in the water. Askstudents to speculate about how thesefeatures are an advantage to jellyfishas predators. l Verbal


FlatwormsWhen you think of worms, you probably think of earthworms. But there are many other kinds of worms. Many of them are too tiny to see without a microscope. The simplest worms are the flatworms. Flatworms are divided into three major classes: planarians (pluh NER ee uhnz) and marine flatworms, flukes, and tapeworms.

All flatworms have bilateral symmetry. Many flatworms also have a clearly defined head and two large eyespots. Even though the eyespots cannot focus, a flatworm knows the direc-tion that light is coming from. Some flatworms also have a bump on each side of their head. These bumps are sensory lobes. Sensory lobes are used for detecting food. You can see these traits in the planarian shown in Figure 9.

✓Reading Check What are the three major classes of flatworms?

PlanariansPlanarians live in freshwater lakes and streams or on land in damp places. Most planarians are predators. They eat other animals or parts of other animals and digest food in a gut. They find food by using their sensory lobes. The planarian’s head, eyespots, and sensory lobes are clues that it has a well-developed nervous system. Planarians even have a brain for processing information about their surroundings.

FlukesFlukes are parasites. A parasite is an organism that invades and feeds on the body of another living organism that is called a host. Most flukes live and reproduce inside the bodies of other animals. A fluke’s fertilized eggs pass out of the other animal’s body with waste products. If these fertilized eggs infect drinking water or food, animals may eat them. The fertilized eggs will develop into new flukes inside the animals.

Flukes have tiny heads without eyespots or sen-sory lobes. They have special suckers and hooks for attaching to animals. Figure 10 shows a fluke.

Figure 9 This planarian has a head with eyespots and sensory lobes. Planarians are often about 15 mm long.

Figure 10 Flukes use suckers to attach to their host. Most flukes are just a few millimeters long.

EyespotSensorylobe

A Walk in the ParkWith your family, take a walk around your neighborhood or a nearby park and make a list of all the invertebrates you find. If you can’t recognize some of the invertebrates, draw them, and try to identify them later using a local guide to invertebrates.


CONNECTIONCONNECTION vvReal World ---------------------------------------------g

Blood Flukes Schistosomiasis is an infectious disease caused by blood flukes of the genus Schistosoma. About 200 million people are afflicted by schistoso-miasis worldwide, primarily in Africa, Latin America, tropical Asia, and the Middle East. Encourage students to research the Schistosoma blood fluke and, as a class, to create a bulletin-board display in which they describe and illustrate the fluke’s complex life cycle, the symptoms of schistosomiasis, and steps thatcan be taken to reduce the chance of infection. l Visual/Verbal


planarians, flukes, and tapeworms

MISCONCEPTIONALERT

Rare Meat Students may think that tapeworm infec-tions are relatively rare among people living in developed countries. Even in the United States, how-ever, tapeworms from pigs and cattle can infect humans. Researchers estimate that about 1% of American cattle are infected with beef tape-worm. About 20% of all beef consumed in the United States is not federally inspected; lightly infected beef is frequently missed dur-ing inspections. As a result, there is a chance of becom-ing infected with beef tape-worm if a person eats rare roast beef, hamburgers, or steaks.

Is That a Fact!The adult broad-fish tapeworm, which can infect humans, grows 10 to 20 m in length and may consist of 3,000 to 4,000 sections. A mature fish tapeworm can shed a million eggs a day.

Figure 12 This hookworm is a tiny larva. Even as an adult, it will be less than 15 mm long.

Figure 11 Tapeworms can reach enormous sizes. Some can grow to be longer than a school bus!

TapewormsTapeworms are similar to flukes. Like flukes, they have a small head with no eyespots or sensory lobes. They live and reproduce in other animals. They also feed on these animals as parasites. But tapeworms have a unique body that is very specialized for their internal environment. Tapeworms do not have a gut. These organisms simply attach to the intestines of another animal and absorb nutrients. The nutrients move directly through the tapeworm’s tissues. Figure 11 shows a tapeworm that can infect humans.

RoundwormsRoundworms have bodies that are long, slim, and round, like spaghetti. Like other worms, they have bilateral symmetry. Roundworms have a simple nervous system. A ring of ganglia forms a simple brain. Parallel nerve cords connect the two ends of their body. Figure 12 shows one kind of roundworm.

Most species of roundworms are very small. A single rotten apple could contain 100,000 roundworms! These tiny worms break down the dead tissues of plants and animals. This proc-ess helps make soil rich and healthy.

Not all roundworms eat dead tissues. Many roundworms are parasites. Some of these roundworms, including pin-worms and hookworms, infect humans. Trichinella spiralis(TRIK i NEL uh spuh RAL is) is a parasitic roundworm that is passed to people from infected pork. This roundworm causes the disease trichinosis (TRIK i NOH sis). This illness causes fever, fatigue, and digestive problems. Cooking pork thoroughly will kill any roundworms living in the meat.

✓Reading Check Name three roundworms that are parasites and that can affect humans.

Tapeworms People and ani-mals can become infected by tapeworms when they swal-low something that contains tapeworm eggs or larvae. These eggs or larvae can come from unclean food, water, or surfaces. Animals can even get tapeworms by swallow-ing infected fleas. In a group, research one of the following topics: What are some differ-ent kinds of tapeworms? What are the effects of tapeworm infection? How can tapeworm infection be prevented? Then, present your research to the rest of the class.

h-----------------------------g

Writing Roundworm Reality Have students research the life cycle of Trichinella spiralis, a species of roundworm

parasites, and write a persuasive paragraph on the importance of cooking pork thor-oughly to prevent the contraction of trichinosis. l Verbal


pinworms, hookworms, and Trichinella spiralis

Reteaching -------------------------------------bTable of Traits To help stu-dents remember the differences between sponges, cnidarians, flatworms, and roundworms, make a table on the board. Label the rows with the four kinds of invertebrates, and label the col-umns “No backbone,” “Gut,” “Bilateral symmetry,” and “Simple brain.” Ask the class to tell you which traits to check off for each invertebrate. l Visual

Quiz ---------------------------------------------------------------------g

1. Describe the nervous system of most simple invertebrates. (Simple invertebrates have nerves arranged in networks or in nerve cords throughout their body. In some invertebrates, nerve cells are grouped into ganglia that control different body parts.)

2. List three kinds of cnidarians. (Answer may include: corals, hydras, jellyfish, and sea anemones)

3.What is the relationship between a parasite and its host? (A parasite is an organism that invades and feeds on another living creature; the organism that the parasite feeds on is the parasite’s host.)


SummarySummary

For a variety of links related to this chapter, go to www.scilinks.org

Review

Using Key Terms

Complete each of the following sentences bychoosing the correct term from the word bank.

invertebrate gutganglion coelom

1. A(n) is a mass of nerve cells that controls ananimal’s actions.

2. A(n) does not have a backbone.

3. The is a special space in an animal’s bodythat surrounds the and other organs.

Understanding Key Ideas

4. Which of the following is a characteristic sharedby all invertebrates?

a. having no backboneb. having radial symmetryc. having a braind. having a gut

5. What do sponges use to digest food?

a. an osculumb. poresc. collar cellsd. a gut

6. Describe cnidarian body forms and stingingcells.

7. How is a roundworm similar to a piece ofspaghetti?

Interpreting Graphics

All invertebrate nervous systems are made up ofsome or all of the same basic parts. The drawingbelow shows the nervous system of a segmentedworm. Use this drawing to answer the questionsthat follow.

8. The letters in the drawing point to nerve cords,a ganglion, and a brain. Which letter points tothe brain? How can you tell?

9. How is the brain connected to the ganglion?

Critical Thinking

10. Making Inferences Explain why it would beimportant for a parasite that its host survive.

•• Invertebrates are animals that do not have a backbone. Most invertebrates have neu-rons and a gut. The gut is surrounded by the coelom.

•• Almost all animals have radial or bilateral symmetry. But some animals, including sponges, are asymmetrical.

•• Sponges filter food from water with collar cells. Collar cells also digest food. Sponges can regenerate body parts. They are classi-fied by their shape.

•• Cnidarians have stinging cells and can have two body forms: the medusa and the polyp. Hydrozoans, jellyfish, and sea anemones and corals are cnidarians.

•• Planarians, flukes, and tapeworms are three classes of flatworms. Planarians have eyespots and sensory lobes. Flukes and tapeworms are parasites.

•• Roundworms are tiny worms that break down dead plant and animal tissue. Some roundworms are parasites.

Topic: Sponges; RoundwormsSciLinks code: HSM1443; HSM1332

b ca

AlternativeAssessment ---------------------------g

PORTFOLIO

Invertebrate FeedingAsk students to create

an illustrated book about theways that sponges, cnidarians,and flatworms obtain food.Students should label the inver-tebrates’ body structures on theillustration and may wish todraw internal views or cross sec-tions to show special cells, inter-nal organs, or body systems.Students should also includetext in which they discuss thefeeding adaptations of the invertebrates. l Verbal/Visual

Answers to Section Review

1. ganglion2. invertebrate3. coelom, gut4. a5. c6. Sample answer: Cnidarian

body forms include the polypand the medusa. Both haveradial symmetry. Polyps areoften sessile, but medusascan move around in the water.Cnidarian stinging cells arecells that contain tiny spearsthat are shot as a defense oras a way to catch food.

7. Roundworms are shapedlike a piece of spaghetti.Both are long, slim, and round.

8. a points to the brain, b pointsto a ganglion, and c points toa nerve cord. A nerve cord isthick and straight, a ganglion isa mass of many nerve cells, anda brain is a mass that is morecomplex than a ganglion.

9. by nerve cords10. Sample answer: A parasite

gets its food from its host. Ifthe parasite killed the host rightaway, the parasite would loseits food source. If the host sur-vives, the parasite has a stablefood supply.

CHAPTER RESOURCES


CRF • Section Quizg• Section Reviewg• Vocabulary and Section Summaryg• Reinforcement Worksheetb


READING STRATEGY

2 Mollusks and Annelid WormsHave you ever eaten clams or calamari? Have you ever seen earthworms on the sidewalk after it rains?

If you have, then you already know a thing or two aboutmollusks and annelid worms. These animals are more com-plex than sponges, cnidarians, flatworms, and roundworms.For example, mollusks and annelid worms have a circulatorysystem that carries materials throughout their bodies.

MollusksSnails, slugs, clams, oysters, squids, and octopuses are all mol-lusks. Most of these animals live in the ocean. But some livein fresh water, and some live on land.

Most mollusks fit into three classes. The gastropods (GAStroh PAHDZ) include slugs and snails. The bivalves include clamsand other shellfish that have two shells. Cephalopods (SEF uhloh PAHDZ) include squids and octopuses.

How Do Mollusks Eat?Each kind of mollusk has its own way of eating. Snails andslugs eat with a ribbonlike organ—a tongue covered with curvedteeth. This organ is called a radula (RAJ u luh). Figure 1 showsa close-up of a slug’s radula. Slugs and snails use the radulato scrape algae from rocks, chunks of tissue from seaweed, orpieces of leaves from plants. Clams and oysters attach to oneplace and use gills to filter tiny plants, bacteria, and otherparticles from the water. Octopuses and squids use tentaclesto grab their food and to place it in their powerful jaws.

Figure 1 The rows of teeth on a slug’s radula help scrape food from surfaces. The radula here has been magnified 2,000 times.

What You Will Learn

Explain how mollusks eat, controlbody functions, and circulate blood.Describe the four body parts thatmost mollusks have in common.Describe the three kinds of annelidworms.

Vocabularyopen circulatory systemclosed circulatory systemsegment

Discussion Read this section silently.Write down questions that you haveabout this section. Discuss yourquestions in a small group.

2

OverviewIn this section, students areintroduced to three majorclasses of mollusks: gastropods,bivalves, and cephalopods.Students learn about mollusks’bodies, feeding habits, and circu-latory systems. Students will alsostudy annelid worms, includingearthworms, marine worms, andleeches.

BellringerHave students unscramble thefollowing words and write a sen-tence that uses all of the words.

• gluss (slugs)

• isalns (snails)

• sdusqi (squids)

• klomssul (mollusks)

(Sample answer: Slugs, snails, andsquids are mollusks.)

GroupGroup vv -------g

Writing Mollusk Menus Organizestudents into groups thatwill research how people

in different countries use mol-lusks for food. Students canlook for recipes for snails, clams,squids, and other mollusks. Askeach group to make a menu thatconsists of an appetizer and amain dish made from mollusks.l Verbal

CHAPTER RESOURCES



Technology


Workbooks


The blue-ringed octopus of the SouthPacific is deadly. When the octopus isprovoked, the blue rings on its skin turnso blue that they almost glow. The salivain its bite contains a powerful toxin forwhich there is no known antidote! Thistoxin paralyzes the victim. If a personbitten by this octopus arrives at thehospital in time, he or she is put on arespirator until the toxin wears off.


Ganglia and BrainsAll mollusks have complex ganglia. They have special gangliato control breathing, movement, and digestion. But octopusesand squids have the most advanced nervous system of all inver-tebrates. Cephalopods, such as the octopus in Figure 2, havelarge brains that connect all of their ganglia. Cephalopods arethought to be the smartest invertebrates.

Pumping BloodUnlike simple invertebrates, mollusks have a circulatory system.The circulatory system transports materials through the body inthe blood. Most mollusks have an open circulatory system. Inan open circulatory system, a simple heart pumps blood throughblood vessels that empty into sinuses, or spaces in the animal’sbody. Squids and octopuses have a closed circulatory system.In a closed circulatory system, a heart pumps blood through anetwork of blood vessels that form a closed loop.

✓Reading Check What is the difference between an open circu-latory system and a closed circulatory system? (See the Appendix foranswers to Reading Checks.)

Mollusk BodiesA snail, a clam, and a squid look quite different from oneanother. Yet if you look closely, you will see that their bod-ies all have similar structures. The body parts of mollusks aredescribed in Figure 3.

A layer of tissue calledthe mantle covers thevisceral mass. The man-tle protects the bodiesof mollusks that do nothave a shell.

In most mollusks, theoutside of the mantlesecretes a shell. Theshell protects the mol-lusk from predators andkeeps land mollusksfrom drying out.

Snail

Squid

Mollusks are known fortheir broad, muscularfoot. The foot helpsthe animal move. Ingastropods, the footmakes mucus that theanimal slides along.

The gills, gut, and otherorgans form the visceralmass (VIS uhr uhl MAS).It lies in the center of amollusk’s body.

Clam FootVisceral mass

MantleShell

KEY

Figure 2 Octopuses arevery smart. If they aregiven stones, they canbuild a cave to hide in.

open circulatory system a circu-latory system in which the circulatoryfluid is not contained entirely withinvessels

closed circulatory system a cir-culatory system in which the heartcirculates blood through a network ofblood vessels that form a closed loop

Body Parts of MollusksFigure 3

CulturalAwarenessCulturalAwareness g

Success Story Giant clamslive in tropical waters of thePacific Ocean. They are a sta-ple in the diet of manyPacific islanders and are adelicacy in many Asian coun-tries. Recently, giant clamshave been threatened byoverfishing. Scientists havebeen working to restore giantclam populations by raisingthousands of these molluskson giant clam “farms” alongprotected coasts. Whenfarmed clams are big enough,they are transplanted to thewild. As a result, giant clamsare once again commonaround many Pacific islands.Ask students to researchother efforts to help restorethreatened invertebratepopulations. l Verbal


An open circulatory system hasa heart that pumps blood throughblood vessels that empty intosinuses. A closed circulatory systemhas a heart that pumps blood througha closed loop of blood vessels.

Hungry Snails Nearly 30 cm long,the giant African snail is native to eastAfrica, where it eats decaying plants.When introduced onto Pacific islands,African snails ate crops and becamepests. A misguided attempt to solve theproblem involved releasing several newsnail species onto the islands. But thepredatory snails ate the islands’ nativesnails instead of the African snails. Nowsome of the native snails are endangered.

Is That a Fact!The large fleshy lobe to the right of theoctopus’s eyes in Figure 2 is not thehead. It contains the visceral mass.

SUPPORT FOR

English LanguageLearnersCombining Information Ifsecond-language users canconnect different types ofnew information, they arefar more likely to retain it.After students have read theparagraphs about mollusksand the diagram showingmollusk body parts, ask themto write a short summarycombining the information.Collect the summaries, andevaluate them for clarity andcompleteness of information.Have students make correc-tions if necessary.l Verbal

Section 2 • Mollusks and Annelid Worms 389

Annelid WormsAnnelid worms are often called segmented worms because their bodies have segments. A segment is an identical, or almost identical, repeating body part. You can see the segments of an earthworm in Figure 4.

Like roundworms and flatworms, annelid worms have bilat-eral symmetry. But annelid worms are more complex than other worms. Annelid worms have a closed circulatory system. They also have a complex nervous system with a brain. A nerve cord connects the brain to a ganglion in each segment.

Annelid worms live in salt water, in fresh water, or on land. They eat plant material or animals. Three major groups of annelid worms are earthworms, marine worms, and leeches.

EarthwormsEarthworms are the most familiar annelid worms. Each earth-worm has 100 to 175 segments. Most of these segments are identical, but some look different from the others. These seg-ments have special jobs, such as eating or reproducing.

Earthworms eat material in the soil. They break down plant and animal matter in the soil and leave behind wastes called castings. Castings help gardens by making the soil richer. Earthworms also improve garden soil by digging tunnels. The tunnels allow air and water to reach deep into the soil.

To move, earthworms use stiff hairs, or bristles, on the outside of their body. The bristles hold the back part of the worm in place while the front part pushes through the soil.

Marine WormsIf there were a beauty contest for worms, marine worms would win. These worms are called polychaetes (PAHL ih KEETS), which means “many bristles.” They are covered in bristles and come in many colors. Figure 5 shows a marine worm. Most of these worms live in the ocean. Some eat mollusks and other small animals. Others filter small pieces of food from the water.

Tail

Reproductivesegments

Head

Figure 5 This marine worm is a predator that eats small animals. Can you see the segments of this worm?

segment any part of a larger structure, such as the body of an organism, that is set off by natural or arbitrary boundaries

Figure 4 Except for the head, tail, and reproductive segments, all of the segments of this earthworm are identical.


Earthworms in Action To demonstrate earthworms’ ability to mix soil, have the class work cooperatively to fill the bottom half of a large glass jar with sand and the top half with potting soil. Add enough water to moisten the soil and the sand, and add 5 to 10 large earthworms (available from sporting goods or hardware

stores) to the jar. Punch air holes in the lid, and place it securely on the jar. Put the jar in a cool, dimly lit location in the class-room. Add water periodically to keep the soil moist. Encourage students to observe how the earthworms gradually mix the soil and sand during the next few weeks. l Visual cc ee

Reteaching -------------------------------------bMollusk Names Help students remember the difference between gastropods, bivalves, and cepha-lopods by teaching them the fol-lowing root words: gastro, whichmeans “stomach,” cephalo, whichmeans “head,” pod, which means “foot,” bi, which means “two,” and valve, which means “door.” Ask students to explain why “stomach foot,” “two doors,” and “head foot” are appropriate names for each group. l Verbal

Quiz ---------------------------------------------------------------------g

1. What are the three main classes of mollusks? (gastro-pods, bivalves, and cephalopods)

2. How do herbivorous snails and slugs use their radula to obtain food? (They use their radula to scrape algae off rocks, chunks of tissue from seaweed, or pieces from plant leaves.)

Alternative Assessment ---------------------------g

Writing Worms Gone Wild Havestudents research how earthworms introduced

into forests in the Midwest by the dumping of bait by fishers are endangering the forests. Students can write a one-page report explaining how worms can be good for gardens, but bad for forests in the Midwest. l Verbal


For a variety of links related to this chapter, go to www.scilinks.org


SummarySummary

ReviewUsing Key Terms

1. Use the following terms in the same sentence: open circulatory system and closed circulatory system.

2. In your own words, write a defi-nition for the term segment.


3. Some mollusks use a radula to

a. scrape algae off rocks.b. filter food from water.c. grab food from water.d. place food in their jaws.

4. What trait do all mollusk nerv-ous systems share? What is unique about squids’ and octo-puses’ nervous systems?

5. What are the four main body parts of most mollusks?

6. Describe three different kinds of annelid worms.

Math Skills

7. If a squid swims at 30 km/h, how far can it swim in 1 min?

Critical Thinking

8. Predicting ConsequencesClams use gills to filter food from water. How could water pollution affect clams?

9. Analyzing Ideas Cephalopods do not have shells. What other traits do they have to help make up for this lack of protection?

Figure 6 Doctors sometimes use leeches to reduce swelling after surgery.

LeechesLeeches are known as parasites that suck other animals’ blood. This is true of some leeches. But other leeches are not parasites. Some leeches are scavengers that eat dead animals. Others are preda-tors that eat insects, slugs, and snails.

Leeches that suck blood can be useful in medi-cine. After surgery, doctors sometimes use leeches to prevent dangerous swelling near a wound. Figure 6shows two leeches being used for this purpose. Leeches also make a chemical that keeps blood thin so that it does not form clots. The leech uses the chemical to keep blood flowing from its host. Doctors use this chemical to prevent blood clots in people with circulation problems. This chemical can also help break down blood clots that already exist.

✓Reading Check What are two ways that doctors use leeches to help people?

• Mollusks get food with gills, a radula, or ten-tacles and jaws.

• Mollusks have a complex nervous system.

• Mollusks have either an open circulatory system or a closed circulatory system.

• All mollusks have a foot, a visceral mass, and a mantle. Most mollusks also have a shell.

• The three major groups of annelid worms are earthworms, marine worms, and leeches.

Topic: Mollusks and Annelid WormsSciLinks code: HSM0986


1. Sample answer: Most mollusks have an open circulatory system, but cephalopods have a closed circulatory system.

2. Sample answer: A segment is one of several repeating body parts that are identical or nearly identical.

3. a4. All mollusk nervous systems

have ganglia. Squids and octo-puses have brains.

5. foot, visceral mass, mantle, and shell

6. Sample answer: Earthworms are common annelid worms that eat material in the soil and use bristles to move. Marine worms are colorful and are covered in bristles. Most live in the ocean. Leeches can be parasites, scav-engers, or predators. Many kinds of leeches suck blood, and some leeches are used by doctors in medical practice.

7. 500 m (30 km/h � 0.5 km/min �500 m/min)

8. Sample answer: Clams could fil-ter pollutants from the water as they try to filter food from the water. These pollutants could be harmful to the clams.

9. Sample answer: A cephalopod’s large brain could help the cepha-lopod avoid predators. The large brain gives a cephalopod intelli-gence and the ability to think.


Doctors use leeches to prevent swelling and to prevent and break down blood clots.

CHAPTER RESOURCES


CRF • Section Quiz g• Section Review g• Vocabulary and Section Summary g

StrategiesStrategiesINCLUSIONINCLUSION

• Hearing Impaired• Learning Disabled• Developmentally DelayedMany students learn better when a little extra time is spent on a topic. Have students use construction paper to create models of segmented worms. Ask students to share their creations. l Kinesthetic ee

Section 2 • Mollusks and Annelid Worms 391

READING STRATEGY

3 ArthropodsHave you ever explored a park or field, looking for living things? How many animals do you think can live on one acre of land? If you could find all the arthropods in that area, you could count more than a million animals!

Arthropods have lived for hundreds of millions of years. Theyhave adapted to nearly every environment. You are probablyfamiliar with many of them, such as insects, spiders, crabs,and centipedes. Arthropods are the largest group of animalson Earth. At least 75% of all animal species are arthropods.

Characteristics of ArthropodsAll arthropods share four characteristics: a segmented bodywith specialized parts, jointed limbs, an exoskeleton, and awell-developed nervous system.

Segmented and SpecializedLike annelid worms, arthropods are segmented. In some arthro-pods, such as centipedes, nearly every segment is identical.Only the segments that make up the head and tail are differentfrom the rest. But most species of arthropods have segmentsthat include specialized structures, such as wings, antennae,gills, pincers, and claws. During an arthropod’s development,some segments grow together. This process forms three mainbody parts. These body parts are the head, the thorax, and theabdomen. You can see these three body parts in Figure 1.

Figure 1 Like most arthropods, this dragonfly has a head, a thorax, and an abdomen.

Abdomen

Thorax

Head

What You Will Learn

List the four main characteristics ofarthropods.Describe the different body parts ofthe four kinds of arthropods.Describe the two types ofmetamorphosis in insects.

Vocabularyexoskeleton antennacompound eye metamorphosis

Prediction Guide Before readingthis section, write the title of eachheading in this section. Next, undereach heading, write what you thinkyou will learn.

3

OverviewIn this section, students learnthat arthropods have jointedlimbs, a segmented body, an exo-skeleton, a well-developed brain,and specialized sense organs.Students are introduced to fourmajor groups of arthropods—centipedes and millipedes, crus-taceans, arachnids, and insects.The section describes insect bod-ies and patterns of development.

BellringerHave students pretend that theycan undergo metamorphosis.Ask students the followingquestions:

• What might you look likewhen you emerge?

• How might you find food,and what might you eat?

• What adaptations that you donot have now might you haveafter metamorphosis?

Discussion ----------------------------------gArthropods Introduce the gen-eral characteristics of arthro-pods. Have students discuss howthese characteristics may havehelped arthropods adapt tonearly all environments and todiversify such that arthropodsmake up the largest group ofanimals on Earth. l Verbal CHAPTER RESOURCES


CRF • Lesson Plan• Directed Reading Ab, Bs

Technology


Workbooks


Math Skills for Science• Dividing Whole Numbers with

Long Divisiong• Checking Division with Multiplicationg

Spreading Silk In 1869, the gypsymoth was introduced into the UnitedStates in an attempt to breed a bettersilkworm. The results were disastrous.Some moths escaped, and the speciesspread throughout the northeastern partof the country. Gypsy moth caterpillarseat the leaves of deciduous trees. Inyears in which there are especially largenumbers of caterpillars, millions of acresof trees can be stripped of their leaves.


Jointed LimbsJointed limbs give arthropods their name. Arthro means “joint,” and podmeans “foot.” Jointed limbs are legs or other body parts that bend at the joints. Having jointed limbs makes it easier for arthropods to move.

An External SkeletonArthropods have a hard outer covering. The hard, external structure that covers the outside of the body is an exoskeleton.You can see a crab’s yellow and white exoskeleton in Figure 2. This structure is made of protein and a special substance called chitin (KIE tin). An exoskeleton does some of the same things that an internal skeleton does. Like your bones, it serves as a stiff frame that supports the body. It also allows the animal to move. An arthropod’s muscles connect to different parts of the skeleton. When the muscles contract, they move the exoskeleton, which moves parts of the animal.

But the exoskeleton also does things that an internal skel-eton doesn’t do well. The exoskeleton acts like a suit of armor to protect organs inside the body. The exoskeleton also keeps water inside the animal’s body. This feature allows arthropods to live on land without drying out.

✓Reading Check How is an exoskeleton similar to an internal skeleton? (See the Appendix for answers to Reading Checks.)

Sensing SurroundingsAll arthropods have a head and a well-developed brain and nerve cord. The nervous system receives information from sense organs, including eyes and bristles. Some arthropods, such as the tarantula, use external bristles to sense their sur-roundings. The bristles detect motion, vibration, pressure, and chemicals.

Some arthropods have very simple eyes. These arthropods can detect light but cannot see images. But most arthropods have compound eyes. Arthropods that have compound eyes can see images. A compound eye is an eye that is made of many identical, light-sensitive units. The fruit fly in Figure 3has two compound eyes.

exoskeleton a hard, external, sup-porting structure

compound eye an eye composed of many light detectors

Figure 3 Compound eyes are made of many identical, light-sensitive units that work together.

Figure 2 A ghost crab’s exoskeleton protects its body from drying out on land.

CONNECTIONCONNECTION vvMath ----------------------------------------------------------------------------a

Compound Eyes The com-pound eyes of insects are made up of tiny bundles of light-sensitive cells called ommatidia(singular, ommatidium). The huge eyes of dragonflies contain about 28,000 ommatidia. The eyes of butterflies contain about 14,000, while those of houseflies have about 4,000. Ask students to calculate roughly how many times more ommatidia dragon-flies have than butterflies or houseflies do. (Dragonflies have roughly twice as many ommatidia as butterflies do and 7 times as many ommatidia as houseflies do.) Then, ask students to speculate on the relationship between the num-ber of ommatidia and the ways that these three types of arthro-pods get food. (Sample answer: Dragonflies are fast-flying predators and need acute vision to spot poten-tial prey and maneuver at high speeds. Many butterflies feed on flowers and must distinguish between flower types by shape and color. Houseflies rely more on odor detection than on vision to find their food, which often consists of dead or stationary organisms.)l Logical ee


Both an exoskeleton and an internal skeleton support an animal’s body and allow the animal to move.

Compass termites from Australia can air-condition their mounds! These insects build towers that are up to 2.5 m long and 3 m high but are narrow and tall. Up to 2 million termites may live inside. These termites build their towers so that large, broad sides face east and west, and narrow sides face north and south. This

design allows the nest to maintain a steady temperature. In the morning and evening, the rising and setting sun hits the broad sides of the nest. But the hot midday sun does not strike a large part of the nest. That way, the nest gets a steady supply of moderate heat through-out the day.

Section 3 • Arthropods 393

Kinds of ArthropodsArthropods are classified by the kinds of body parts they have. You can tell the difference between arthropods by looking at the number of legs, eyes, and antennae they have. An antenna isa feeler that senses touch, taste, or smell.

Centipedes and MillipedesCentipedes and millipedes have one pair of antennae, a hard head, and one pair of mandibles. Mandibles are mouthparts that can pierce and chew food. One way to tell these animals apart is to count the number of legs on each segment. Centipedes have one pair of legs on each segment. They can have 30 to 354 legs. Millipedes have two pairs of legs on each segment. The record number of legs on a millipede is 752! Figure 4shows a centipede and a millipede. How many legs can you count on each?

CrustaceansShrimps, barnacles, crabs, and lobsters are crustaceans. Most crustaceans live in water. They have gills for breathing in the water, mandibles for eating, and two compound eyes. Each eye is located on the end of an eyestalk. Unlike all other arthro-pods, crustaceans have two pairs of antennae. The crustaceans in Figure 5 show some of these traits. The lobster’s gills are located under the exoskeleton.

Eyestalk

Antenna

Figure 5 Water fleas and lobsters are two kinds of crustaceans.

Figure 4 Centipedes eat other animals. Millipedes eat plants.

Centipede

Millipede

antenna a feeler that is on the head of an invertebrate, such as a crustacean or an insect, that senses touch, taste, or smell

Antenna

vv--------------------------------------g

Making Models It is a common misconception that spiders are insects. Challenge students to disprove this misconception by using modeling clay and pipe cleaners to create models of a spider and an insect. Have stu-dents read this section before they begin. Students’ models should reflect that spiders have two main body parts, four pairs of legs, and no antennae, whereas insects have three main body parts, three pairs of legs, and one pair of antennae. l Kinesthetic ee


Have students work in coopera-tive groups of three or four to research web-building spiders. Each group should investigate one spider species. Have each group use string or yarn to create an example of the type of web that the chosen species builds. Guide students in a class discussion in which they compare the web shapes and designs. l Kinesthetic/ Interpersonalcc ee

INTERNETINTERNET vvSequence Board -------------g

For an internet activity related to this chapter, have students go to go.hrw.com and type in the keyword HL5INVW.

CONNECTION toCONNECTION toChemistry -----------------------------------------------g

Chitin Chitin is a strong, flexible, water-proof poly saccharide (a polymer of glucose). Chitin molecules bond readily with pro-teins, such as those found in the exoskel-etons of arthropods. A Japanese textile and fiber manufacturing company has exploited chitin’s unique chemical proper-ties to create chitin sutures for surgery and

chitin-based artificial skin. Chitin sutures don’t have to be removed because they dissolve in the body; they also bind so well with proteins that they may promote healing. Ask students to research how chi-tin is used in modern medical practices. They can present their results to the class in an oral presentation. l Verbal


ArachnidsSpiders, scorpions, mites, and ticks are arachnids(uh RAK nidz). Figure 6 shows the two mainbody parts of an arachnid: the cephalothorax(SEF uh loh THAWR AKS) and the abdomen. Thecephalothorax is made of both a head and athorax. Most arachnids have four pairs of legs.They have no antennae. Instead of mandibles,they have a pair of clawlike mouthparts calledchelicerae (kuh LIS uhr EE). And instead of com-pound eyes, they have simple eyes. The numberof eyes varies—some spiders have eight eyes!

Though some people fear spiders, these arachnids are morehelpful than harmful. A few kinds of spider bites do needmedical treatment. But the chelicerae of many spiders cannoteven pierce human skin. And spiders usually use their chelic-erae to catch small insects. Spiders kill more insect pests thanany other animal does.

Ticks live in forests, brushy areas, and even grassy lawns.Their bodies can be just a few millimeters long. The segmentsof these small bodies are joined as one part. Ticks are parasitesthat use chelicerae to slice into a host’s skin. These parasitesattach onto the host and feed on the host’s blood. A few ticksthat bite humans can carry diseases, such as Lyme disease. Butmost people who are bitten by ticks do not get sick.

✓Reading Check How are spiders helpful to humans?

InsectsInsects make up the largest group of arthropods. If you putall the insects in the world together, they would weigh morethan all the other animals combined! Figure 7 shows a fewkinds of insects. Although they look different, they all havethree main body parts, six legs, and two antennae.

Figure 6 Arachnids have twomain body parts and specialmouthparts called chelicerae.

Cephalothorax

Chelicerae

Dragonfly

Figure 7 These are just a few ofthe many different insects. Canyou see any traits that they havein common?

Sticky Webs1. Place a piece of tape on your desk, sticky side up. The tape

represents a web. Your fingers will represent an insect’s legs,and then they will represent a spider’s legs.

2. Holding the tape in place by the edges, “walk” your fingersacross the tape. What happens?

3. Dip your fingers in cooking oil, and “walk” them across thetape again. What happens this time?

4. Use the results to explain why spiders don’t get stuck in webs.

Bumblebee

Prayingmantis

Abdomen

M A T E R I A L SFOR EACH STUDENT

• oil, cooking• tape, transparent

Answers

2. Students’ fingers should stickto the tape.

3. Students’ fingers should notstick to the tape.

4. The oil makes the fingers slip-pery so that they will not stickto the tape. Some spiderssecrete a nonstick substancethat keeps their legs fromsticking to their webs. (Note:Some spiders avoid stickingto their webs by stepping onlyon certain nonstick parts ofthe web. Others do not havesticky webs, but catch foodwhen insects get tangled in amess of nonstick silk strands.)


Spiders are helpful because they catchsmall insects that are pests to humans.

Is That a Fact!The hind legs of the human flea, Pulexirritans, are especially adapted for jumping.How high can a flea jump? P. irritanscan leap 33 cm horizontally and 20 cmvertically, which is comparable to an85 m high jump for a human!

SUPPORT FOR

English LanguageLearnersScientific Definitions Em-phasize to students that scien-tific language is more preciseand detailed than generalEnglish, so the term insect hasa very specific meaning to ascientist. To practice makingthis distinction, give groupsof 4 students pictures of centi-pedes, millipedes, insects, andarachnids from magazines.Ask them to place the picturesin a four-column chart underthe correct headings. Modelthe chart on the board for stu-dents to copy. Allow studentsto review the relevant pagesof this section as necessary.Monitor group progress toensure accuracy, occasionallyasking why the group choseto place a picture in a givencolumn. l Visual


The World of InsectsInsects live on land, in fresh water, and on ocean surfaces.The only place on Earth where insects do not live is in theoceans. Many insects are helpful. Most flowering plants dependon insects to carry pollen between plants. Farmers depend oninsects to pollinate fruit crops. But some insects are pests thatdestroy crops or spread disease. And others, such as fleas andmosquitoes, bite us and suck our blood.

Insect BodiesAs shown in Figure 8, an insect’s body has three parts: the head,the thorax, and the abdomen. On the head, insects have onepair of antennae, one pair of compound eyes, and mandibles.The thorax is made of three segments, each of which has onepair of legs. Some insects have no wings. Others may haveone or two pairs of wings on the thorax.

Complete MetamorphosisAs an insect develops, it changes form. This process is calledmetamorphosismetamorphosis (MET uh MAWR fuh sis). Most insects go througha complex change called complete metamorphosis. As shownin Figure 9, complete metamorphosis has four main stages: egg,larva, pupa (PYOO puh), and adult. Butterflies, beetles, flies,bees, wasps, and ants go through this change.

Figure 8 All insect bodies have these three main parts.

metamorphosismetamorphosis a phase in the life cycle of many animals during which a rapid change from the immature form of an organism to the adult form takes place

The Stages of Complete MetamorphosisFigure 9

a An adult lays eggs. Anembryo forms inside each egg.

b A larva hatches from the egg. But-terfly and moth larvae are called cat-erpillars. The caterpillar eats leaves and grows rapidly. As the caterpillar grows, it sheds its outer layer several times. This process is called molting.

c After its final molt, the cater-pillar makes a chrysalis and becomes a pupa. The pupal stage may last a few days or several months. During this stage, the insect is inactive.

d Adult body parts replace the larval body parts. The adult splits its chrysalis.

e The adult butterfly pumps blood-like fluid into its wings until they are full-sized. The butterfly is now ready to fly.

Abdomen

Thorax

Head

vv---------------------------------------------------a

PORTFOLIO

Insecticide Alternatives Insecti-cides are routinely sprayed on

lawns and gardens to kill insect pests.Unfortunately, these chemicals also killmany beneficial insects, remain in theenvironment for long periods of time,and accumulate in the bodies of animals(including people) that are higher up the

food chain. In recent years, a variety of bio-logical controls that are much more envi-ronmentally safe have been developed tocontrol insect pests. Have students invest-igate different biological controls andcreate a poster on the topic that couldbe displayed at a local garden center.l Verbal/Visual

Reteaching -------------------------------------bWriting Crustaceans Have stu-

dents describe a lobsterand list the characteris-

tics that make the lobster a crustacean. l Verbal

Quiz --------------------------------------------------------------------g

Ask students whether each ofthe following statements is trueor false:

1. The cephalothorax of a spiderconsists of a head and athorax. (true)

2. The legs of most insects attachto the abdomen. (false)

3. Some types of insects livedeep in ocean waters. (false)

4. The stages of complete meta-morphosis are egg, nymph,and adult. (false)

AlternativeAssessment ---------------------------g

Writing Arthropod EncountersHave students write anarrative in which they

describe a walk along a rockyocean shore or through a tropi-cal rain forest. Have themdescribe at least a dozen differ-ent arthropods that they arelikely to encounter. Studentsshould research the two ecosys-tems before they begin writing.Some students may wish tocreate illustrations or collagesto accompany theirnarratives.l Verbal PORTFOLIO


For a variety of links related to thischapter, go to www.scilinks.org

SummarySummary


1. Use the following terms in thesame sentence: compound eyeand antenna.

2. In your own words, write adefinition for each of the follow-ing terms: exoskeleton andmetamorphosis.


3. Which of the following is NOTa trait shared by all arthropods?

a. exoskeletonb. body segmentsc. antennaed. jointed limbs

4. Which of the following arthro-pods is an arachnid?

a. butterflyb. tickc. centipeded. lobster

5. What is the difference betweencomplete metamorphosis andincomplete metamorphosis?

6. Name the four kinds of arthro-pods. How do their bodiesdiffer?

7. Which arthropods have chelic-erae? Which have mandibles?

Math Skills

8. How many segments does amillipede with 752 legs have?How many segments does a cen-tipede with 354 legs have?

Critical Thinking

9. Applying Concepts Supposethat you find an arthropod in aswimming pool. The organismhas compound eyes, antennae,and wings. Is it a crustacean?Why or why not?

10. Forming Hypotheses Sup-pose you have found severalcocoons on a plant outside yourschool. Develop a hypothesisabout what animal is inside thecocoon. How could you find outif your hypothesis is correct?

Figure 10 The grasshopper nymphslook like smaller versions of the adult.

Incomplete MetamorphosisGrasshoppers and cockroaches are some of the insectsthat go through incomplete metamorphosis. Incompletemetamorphosis is less complicated than complete meta-morphosis. As shown in Figure 10, incomplete metamor-phosis has three main stages: egg, nymph, and adult.Some nymphs shed their exoskeleton several times in aprocess called molting.

An insect in the nymph stage looks very much likean adult insect. But a nymph does not have wings and isvery small. Through molting, it develops into an adult.

✓Reading Check What are the three stages of incompletemetamorphosis?

Adult

Eggs

Nymph

Nymph

Nymph

• At least 75% of allanimal species arearthropods.

• The four main character-istics shared by arthro-pods are jointed limbs, ahard exoskeleton, bodysegments, and a well-developed nervoussystem.

• The four kinds of arthro-pods are centipedes andmillipedes, crustaceans,arachnids, and insects.Insects are the largestgroup.

• Insects can go throughcomplete or incompletemetamorphosis.

Topic: ArthropodsSciLinks code: HSM0098


1. Sample answer: Insects usetheir compound eyes andantennae to sense theirsurroundings.

2. Sample answer: An exoskel-eton is a hard, supporting outercovering. Metamorphosis is aphase during which an organ-ism changes from an immatureform to an adult.

3. c4. b5. Incomplete metamorphosis

has three stages: egg, nymph,and adult. Nymphs look likesmaller adults. Complete meta-morphosis has four stages: egg,larva, pupa, and adult. Larvaelook much different than adults.

6. Sample answer: centipedesand millipedes, crustaceans,arachnids, and insects; Centi-pedes and millipedes have onepair of antennae, mandibles, andone or two pairs of legs per seg-ment. Crustaceans have mandi-bles, compound eyes, and twopairs of antennae. Arachnidshave an abdomen and a cepha-lothorax, chelicerae, and noantennae. Insects have a head,thorax, and abdomen, and theyhave one pair of antennae andmandibles. Some insects havewings.

7. Arachnids have chelicerae.Centipedes, millipedes, crusta-ceans, and insects havemandibles.

8. A millipede that has 752 legshas 188 segments. A centipedethat has 354 legs has 177segments.

9. No, the arthropod is not acrustacean because crusta-ceans do not have wings.

10. Sample answer: You couldhypothesize that the animal isan insect in the pupa stage ofcomplete metamorphosis. Thus,the animal could be a butterfly,beetle, fly, bee, wasp, or ant. Tofind out if you were correct, youcould wait for the cocoon tocontinue developing throughmetamorphosis and see whatanimal emerges as an adult.


egg, nymph, and adultCHAPTER RESOURCES


CRF • Section Quizg• Section Reviewg• Vocabulary and Section Summaryg• SciLinks Activityg• Datasheet for Quick Lab

Technology

Transparencies• L53 The Stages of Complete Metamorphosis• L54 Incomplete Metamorphosis


READING STRATEGY

4 EchinodermsWould you touch an object that was covered in sharp spines? Probably not—the spines could hurt you! Some invertebrates are covered in spines that protect them from predators. The predators avoid spines, just like you do.

These spiny invertebrates are called echinoderms (ee KIE nohDUHRMZ). Sea stars (starfish), sea urchins, and sand dollars aresome familiar members of this group. All echinoderms aremarine animals. That means they live in the ocean. Echino-derms live on the sea floor in all parts of the world’s oceans.Some of them eat shellfish, some eat dead plants and animals,and others eat algae that they scrape off rocks.

Spiny SkinnedThe name echinoderm means “spiny skinned.” But the animal’sskin is not the spiny part. The spines are on the animal’s skel-eton. An echinoderm’s internal skeleton is called anendoskeletonendoskeleton (EN doh SKEL uh tuhn). Endoskeletons can behard and bony or stiff and flexible. The spines covering theseskeletons can be long and sharp. They can also be short andbumpy. The animal’s skin covers the endoskeleton.

Bilateral or Radial?Adult echinoderms have radial symmetry. But they developfrom larvae that have bilateral symmetry. Figure 1 shows a seaurchin larva and an adult sea urchin. Notice how the sym-metry is different in the two forms.

Figure 1 The sea urchin larva has bilateral symmetry. The adult sea urchin has radial symmetry.

Larva Adult

endoskeletonendoskeleton an internal skeleton made of bone or cartilage

What You Will Learn

Describe the endoskeleton, nervoussystem, and water vascular system ofechinoderms.Explain how an echinoderm’s bodysymmetry changes with age.Describe five classes of echinoderms.

Vocabularyendoskeletonwater vascular system

Paired Summarizing Read thissection silently. In pairs, take turnssummarizing the material. Stop todiscuss ideas that seem confusing.

4

OverviewIn this section, students areintroduced to echinoderms,including sea stars, brittle starsand basket stars, sea urchinsand sand dollars, sea lilies andfeather stars, and sea cucumbers.Students learn that echinodermshave an endoskeleton, spinyskin, radial symmetry in adult-hood, a simple nervous system,and a water vascular system.

BellringerHave students write down theirthoughts about the followingquestion: “Echinoderms includemarine animals such as sea stars,sea urchins, and sea cucumbers.All these organisms are slow-moving bottom dwellers. Howdo you think that they protectthemselves from predators?”

vv---------------------------------------------------g

Sea Star Hypotheses Displayan example of an echinoderm,such as a sea star. Have studentsdraw the echinoderm in theirscience journal and write abrief hypothesis describing whatit eats, how it moves, and whereit most likely lives. Discuss stu-dents’ answers before beginningthe section.l Verbal/Visual ee CONNECTION toCONNECTION to

Earth Science ---------------------------g

Marine Life Echinoderms are members ofthe benthos, the organisms that live on theocean floor. Use the teaching transparency“The Three Groups of Marine Life” to illus-trate the ocean context of echinoderms.l Visual

CHAPTER RESOURCES



Technology

Transparencies • Bellringer

• L55 The Water Vascular System • LINK TOLINK TO EARTH SCIENCEEARTH SCIENCE E51 The Three Groups

of Marine Life

Workbooks



Nervering

Radialnerve

The Nervous SystemAll echinoderms have a simple nervous system similar tothat of a jellyfish. Around the mouth is a circle of nervefibers called the nerve ring. In sea stars, a radial nerve runsfrom the nerve ring to the tip of each arm, as shownin Figure 2. The radial nerves control the movements ofthe sea star’s arms.

At the tip of each arm is a simple eye that senseslight. The rest of the body is covered with cells thatsense touch and chemical signals in the water.

✓Reading Check How are the movements of a sea star’sarms controlled? (See the Appendix for answers to Reading Checks.)

Water Vascular SystemOne characteristic that is unique to echinoderms is the watervascular system. The water vascular system is a system of canalsfilled with fluid. It uses water pumps to help the animal move,eat, breathe, and sense its environment. Figure 3 shows thewater vascular system of a sea star. Notice how water pressurefrom the system is used for many functions.

Figure 2 Sea stars have a simplenervous system.

water vascular system a systemof canals filled with a watery fluidthat circulates throughout the bodyof an echinoderm

The Water Vascular SystemFigure 3

Water enters the system throughholes in a flat plate on top ofthe sea star. This plate is calledthe sieve plate.

a

Each tube foot connects to abulb called an ampulla (amPUHL uh). The ampulla con-trols fluid pressure so thateach tube foot can extend orretract, hang on or let go. Asthe tube feet and arm movetogether, the sea star movesslowly along the sea floor.

e

The water flows through a tube tothe ring canal around the mouth.

b

From the ring canal, the water flowsinto radial canals in the arms.

c

The radial canals connect to dozens of tiny suckerscalled tube feet. Sea stars use tube feet to moveand to capture food. Oxygen enters and wastesleave through the thin walls of the tube feet.

d

READINGSTRATEGY -----------------g

Prediction Guide Before stu-dents read this page, ask the fol-lowing question: “How does astarfish move from place toplace?”

a. It curls up its arms and rollsacross the sea floor.

b. It uses suction cup–like tubefeet that systematically attachand release to move along.

c. It uses its spines to dig intothe sea floor and pull itselfforward.

d.By using its long arms, a star-fish swims slowly through thewater.

l Verbal

vv---------------------------------------------------gWriting Concept Mapping Have

students make a conceptmap in their science

journal by using the termsthat describe echinoderms’physical characteristics andnervous and water vascularsystems. Students should con-nect at least 12 terms and linkthe terms with meaningfulphrases. Encourage students toshare their concept maps withthe class. l Verbal/Visual

Echinoderm MetamorphosisMost adult echinodermseither are sessile or moveslowly over the sea floor. Butechinoderm larvae are able toswim, and with the help ofocean currents, they oftentravel great distances beforethey settle and change intoadults. Ask students why it isan advantage for echinodermlarvae to have bilateral sym-metry and for adults to haveradial symmetry.


Radial nerves control the movementsof a sea star’s arms.

SUPPORT FOR

English Language LearnersBilateral or Radial Remind students ofwords that begin with bi- from previ-ous chapters. If lateral means “side”,what does bilateral mean? Ask studentsto describe orally the photos of the seaurchin larva and adult. Steer the descrip-tions to emphasize the similarity ofthe larva’s two sides and the all-aroundsimilarities in the adult. Write correctwords from the descriptions on theboard under the headings bilateral orradial. Have students copy the chart forfuture reference.l Visual/Verbal Section 4 • Echinoderms 399

Kinds of EchinodermsScientists divide echinoderms into five major classes. Sea stars are the most familiar echinoderms, and they make up one class. But there are other classes of echinoderms that may not be as familiar to you.

Brittle Stars and Basket Stars Brittle stars and basket stars look like their close relatives, sea stars. But these echinoderms have long, slim arms and are often smaller than sea stars. Also, they don’t have suckers on their tube feet. Figure 4 shows a brittle star and a basket star.

Sea Urchins and Sand DollarsSea urchins and sand dollars are round. Their endoskeletons form a solid, shell-like structure. As shown in Figure 5, theyhave no arms. But they use their tube feet to move in the same way that sea stars move. Some sea urchins can also walk on their spines. Sea urchins feed on algae they scrape from rocks and other objects. They chew the algae with special teeth. Sand dollars burrow into soft sand or mud. They eat tiny particles of food they find there.

Figure 4 Brittle stars and basket stars move around more than other echinoderms do.

Figure 5 Sea urchins and sand dollars use their spines for defense and for movement.

Brittle star

Sea urchin Sand dollars

Basket star


Reteaching -------------------------------------bReinforcing Knowledge Ask students to write down a type of echinoderm. Collect the papers, shuffle them, and redistribute them so that each student has one. Students should draw a representative specimen of the echinoderm, label its features, and note important facts about that echinoderm. l Verbal

Quiz --------------------------------------------------------------------g

1. Name five major groups of echinoderms. (sea stars, brittle stars and basket stars, sea urchins and sand dollars, sea cucumbers, and sea lilies and feather stars)

2. What does the water vascular system enable echinoderms to do? (Echinoderms use the water vascular system to move, eat, breathe, and sense their environment.)

Alternative Assessment ---------------------------g

Compare and Contrast Havestudents compare and contrast the members of the five main classes of echinoderms discussed in the text. Students may wish to include a chart that lists char-acteristics that all echinoderms have in common and character-istics that are unique to each class of echinoderms. l Verbal

CulturalAwarenessCulturalAwareness g

What’s Cooking? Sea cucumbers are a prized ingredient in many Asian foods. Organize the class into groups, and assign each group one of the following research topics: cultures that use sea cucumbers as a cooking ingredient, types of sea cucum-bers that are most popular as food, recipes that include sea cucumbers, and ways in which sea cucumbers are harvested and prepared for market. Have each group report its findings to the class. l Verbal

Is That a Fact!The long-spined black urchin found in Caribbean waters can rotate its spines to point at any moving object above it.

For a variety of links related to thischapter, go to www.scilinks.org


SummarySummary


1. Use each of the following termsin a separate sentence: endoskel-eton and water vascular system.


2. Which of the following is NOTa trait found in echinoderms?

a. an endoskeletonb. spiny skinc. a water vascular systemd. a nerve ring

3. What is the path taken by wateras it flows through the parts ofthe water vascular system?

4. How are sea cucumbers differentfrom other echinoderms?

5. How does an echinoderm’s bodysymmetry change with age?

6. Name five different classes ofechinoderms. List at least onetrait for each group.

Math Skills

7. A sea lily lost 12 of its 178 armsin a hurricane. What percentageof its arms were NOT damaged?

Critical Thinking

8. Making Comparisons How areechinoderms different from andsimilar to other invertebrates?

9. Making Inferences Suppose youfound a sea star with four longarms and one short arm. Whatmight explain the difference?

Figure 6 Like sea stars, brittlestars, and basket stars, featherstars can regrow lost arms.

Sea Lilies and Feather StarsSea lilies and feather stars may have 5 to 200 feathery arms.Their arms stretch away from their body and trap small piecesof food. A sea lily’s cup-shaped body sits on top of a long stalk,which sticks to a rock. Feather stars, such as the one shown inFigure 6, do not have a stalk.

✓Reading Check What is the difference between a feather star anda sea lily?

Sea CucumbersLike sea urchins and sand dollars, sea cucumbers have no arms.A sea cucumber has a soft, leathery body. Unlike other echi-noderms, sea cucumbers are long and have a wormlike shape.Figure 7 shows a sea cucumber.

Figure 7 Like otherechinoderms, sea cucumbersmove with tube feet.

• Echinoderms are marineanimals that have anendoskeleton, a watervascular system, and anerve ring with radialnerves.

• Echinoderms start lifewith bilateral symmetryand then develop radialsymmetry.

• The different classes ofechinoderms include seastars, sea urchins andsand dollars, brittle starsand basket stars, featherstars and sea lilies, andsea cucumbers.

Topic: EchinodermsSciLinks code: HSM0458


1. Sample answer: An echinoderm’sendoskeleton is underneath itsskin. A sea star uses its watervascular system to move,eat, breathe, and sense itsenvironment.

2. b3. Water enters through a sieve

plate and flows into a ring canal.From there, water flows downradial canals that are connectedto tube feet. Water pressure inthe tube feet is regulated bybulbs called ampullae.

4. Sea cucumbers have a long andwormlike shape.

5. As larvae, echinoderms havebilateral symmetry. As adults,echinoderms have radialsymmetry.

6. Sea stars have suckers on tubefeet. Brittle stars and basketstars have long, slim arms. Seaurchins and sand dollars areround. Sea lilies and featherstars may have 5 to 200 arms.Sea cucumbers have a wormlikeshape.

7. 93% (178 � 12 � 166;166 � 178 � 0.93)

8. Sample answer: Echinodermsdiffer from other invertebrates inthat echinoderms have an endo-skeleton and a water vascularsystem, whereas other inverte-brates do not. Echinoderms aresimilar to other invertebratesbecause echinoderms do nothave a backbone.

9. Sample answer: Sea stars canregrow lost arms. The sea starthat has four long arms and oneshort arm is probably in the pro-cess of regrowing a lost arm.


A sea lily’s body is at the end of a long stalk,while a feather star does not have a stalk.

CHAPTER RESOURCES


CRF • Section Quizg• Section Reviewg• Vocabulary and Section Summaryg• Reinforcement Worksheetb• Critical Thinkinga

Section 4 • Echinoderms 401

LabSkills PracticeUsing Scientifi c Methods

Observe the structure of asponge.

Determine how the size ofa sponge’s holes affect theamount of water the spongecan absorb.

• beaker• bowl (large enough for spongeand water)

• calculator (optional)• kitchen sponge

• natural sponge• paper towel

• water

Soaking SpongesEarly biologists thought sponges were plants because spongesare like plants in some ways. In many species, the adults attachto a surface and stay there. They cannot chase their food.Instead, sponges absorb and filter a lot of water to get food.In this activity, you will observe the structure of a sponge. Youwill also consider how the size of the sponge’s holes affectsthe amount of water the sponge can absorb.

Ask a Question

1 Look at the natural sponge. Identify the pores on the outsideof the sponge. See if you can find the sponge’s central cavitiesand oscula.

2 Notice the size and shape of the sponge’s holes. Look at theholes in the kitchen sponge and the paper towel. Think of aquestion about how the holes in each item affect its ability toabsorb water.

Form a Hypothesis

3 Formulate a testable hypothesis to answer your question.Record your hypothesis.

MATERIALS

SAFETY

OBJECTIVES

Skills PracticeSkills Practice LabLab

Soaking Sponges

Teacher’s Notes

Time RequiredOne 45-minute class period

Lab Ratings

rTeacher Prep ff

Student Set-Up f

Concept Level f

Clean Up f

Safety CautionRemind students to review allsafety cautions and icons beforebeginning this lab activity.

Preparation NotesMany students have nevertouched a natural sponge. Allowthem a few moments to experi-ence the feel of a natural sponge,and help them identify the struc-tures. Tell them that sponges areanimals even though they don’tappear animal-like. Discuss howsponges obtain food. This activ-ity is not designed to produceone “right” answer. Instead, itis designed to teach studentsthe value of experimentation.Students may learn that experi-ments can produce unexpectedresults.

CHAPTER RESOURCES


CRF • Datasheet for Chapter Lab• Lab Notes and Answers

Technology

Classroom Videos• Lab Video

• The Cricket CaperKathy LaRoe

East Valley Middle SchoolEast Helena, Montana

Holt Lab Generator CD-ROMSearch for any lab by topic, standard, difficulty level,or time. Edit any lab to fit your needs, or create yourown labs. Use the Lab Materials QuickList softwareto customize your lab materials list.

CLASSROOM

TESTED& APPRO

VED


Test the Hypothesis

4 Read steps 5—9. Design and draw a data table for the data that you will collect. Remember, you will collect data for the natural sponge, the kitchen sponge, and the paper towel.

5 Use a balance to measure the mass of the natural sponge. Record the mass.

6 Place the natural sponge in the bowl. Use the graduated cylinder to add water to the sponge, 10 mL at a time, until the sponge is completely soaked. Record the amount of water added.

7 Gently remove the sponge from the bowl. Measure the amount of water left in the bowl. How much water did the sponge absorb? Record your data.

8 Calculate how many milliliters of water your sponge holds per gram of dry sponge. For example, if your sponge’s dry mass is 12 g and it holds 59.1 mL of water, then your sponge holds 4.9 mL of water per gram (59.1 mL �12 g � 4.9 mL/g).

9 Repeat steps 5—8 with the kitchen sponge and the paper towel.

Analyze the Results

1 Analyzing Results Compare your results from steps 5—9. Which item held the most water per gram of dry mass?

Draw Conclusions

2 Evaluating Data Did your results support your hypothesis? Explain your answer.

3 Evaluating Results Do you see a connection between the size of an item’s holes and its ability to hold water?

4 Analyzing Results What can you conclude about how the size and shape of a sponge’s holes affect its feeding ability?

Applying Your DataUse the Internet to see if scientists have done research that backs up

your ideas about how the size and shape of a sponge affect its feeding abilities. Write your findings in a report to present to the class.

WRITINGSKILL

Chapter 15 • Chapter Lab 403

Analyze the Results

1. Answers may vary depending on the materials used.

Draw Conclusions

2. Answers may vary depending on each student’s hypothesis. In some cases, results will sup-port the hypoth esis. In other cases, they will not.

3. Answers may vary depending on the materials used.

4. Answers may vary. Students should explain that the charac-teristics that allow for more water absorbtion would result in sponges having a greater opportunity for feeding because more water would pass through their osculum and pass by their collar cells.

Applying Your DataAnswers may vary depending on students’ hypotheses about how the size and shape of a sponge’s holes affect its feeding ability. Accept any reasonable answers that are based on scientific research.

CHAPTER RESOURCESWorkbooks

Labs You Can Eat• Here’s Looking at You, Squid g

Inquiry Labs• At a Snail’s Pace a

Long-Term Projects & Research Ideas• Creepy, Crawly Food? a

USING KEY TERMS

UNDERSTANDING KEY IDEAS

1 In your own words, write a defi nition for each of the following terms: gan-glion, water vascular system, and coelom.

2 Use the following terms in the same sentence: open circulatory system and invertebrate.

Complete each of the following sen-tences by choosing the correct term from the word bank.

antennae exoskeletoncoelom gutcompound eyes metamorphosisendoskeleton segments

3 Almost all invertebrates digest food in a(n) .

4 Repeating make up the bodies of annelid worms and arthropods.

5 A crab’s keeps it from losing water.

6 Arthropods use to see images.

7 Echinoderms have spines on their .

8 Arthropods use to touch, taste, and smell.

9 Insects change form during .

Multiple Choice

0 No invertebrates have

a. a brain.b. a gut.c. ganglia.d. a backbone.

q Which animals have a nerve ring?

a. spongesb. echinodermsc. crustaceansd. fl atworms

w Which of the following is NOT a fl atworm?

a. a tapewormb. an earthwormc. a planariand. a fl uke

e Which body part is NOT present in all mollusks?

a. footb. visceral massc. mantled. shell

Short Answer

r Describe how a sponge eats.

t What are the four main characteristics of arthropods?

y Describe the body of a roundworm.

u What are three ways that different mollusks eat?

i Which insects go through complete metamorphosis? go through incom-plete metamorphosis?

o How is an adult echinoderm different from an echinoderm larva?

p How are cephalopod nervous systems unique among mollusks?


14. Sample answer: Water enters the sponge through its pores. Collar cells that line the osculum filter and then digest small parti-cles from the water.

15. Arthropods have jointed limbs, an exoskel eton, segmented bodies, and a well-developed brain that receives information from sense organs.

16. A roundworm’s body is long, slender, and round.

17. by scraping food with a radula, by filtering food with gills, and by grabbing food with tentacles that carry food to the jaws

18. complete metamorphosis: butterflies, bee-tles, flies, bees, wasps, and ants; incom-plete metamorphosis: grasshoppers and cockroaches

19. Adult echinoderms are radially symmetrical and usually remain in one place. Larvae are bilaterally symmetrical and move around.

20. Cephalopods have large brains that con-nect all of their ganglia.

ANSWERS

Using Key Terms1. Sample answer: A ganglion

is a mass of nerves. A water vascular system is a series of canals that are filled with fluids. A coelom is a space in the body that surrounds the internal organs.

2. Sample answer: Most inver-tebrates have an open circulatory system.

3. gut4. segments5. exoskeleton6. compound eyes7. endoskeleton8. antennae9. metamorphosis

Understanding Key Ideas10. d11. b12. b13. d

Assignment GuideSECTION QUESTIONS

1 3, 10, 14, 16, 22

2 13, 17, 20, 23, 26

3 5–6, 8–9, 15, 18, 25, 27–30

4 7, 11, 19

1 and 2 2, 12, 24

1 and 4 1

2 and 3 4

1, 2, 3, and 4 21

INTERPRETING GRAPHICSCRITICAL THINKING

aConcept Mapping Use the followingterms to create a concept map: seg-ments, invertebrates, endoskeleton, anten-nae, exoskeleton, water vascular system,metamorphosis, and compound eyes.

sApplying Concepts You have dis-covered a new animal that has radialsymmetry and tentacles with stingingcells. Can this animal be classifi ed as acnidarian? Explain.

dMaking Inferences Unlike other mol-lusks, cephalopods can move quickly.Based on what you know about thestructure and function of mollusks,why do you think that cephalopodshave this ability?

fMaking Comparisons Why don’troundworms, fl atworms, and annelidworms belong to the same group ofinvertebrates?

gAnalyzing Processes Butterfl ies mateas adults and spend time eating andgrowing in their other stages. Theyhave no wings during the larval orpupal stage of metamorphosis. Canyou think of a reason that they wouldneed wings in their adult form morethan in the other stages of develop-ment? Explain your answer.

a

b

hPredicting Consequences How doearthworms affect gardens? What doyou think would happen to a gardenif the gardener removed all the earth-worms from it?

The picture below shows an arthropod.Use the picture to answer the questionsthat follow.

jName the body segments labeled a, b,and c.

kHow many legs does this arthropodhave?

lTo which segment are the arthropod’slegs attached?

;What kind of arthropod is this?

c

Critical Thinking21. An answer to this exercise can

be found at the end of thisbook.

22. Sample answer: Yes, it canbe classified as a cnidarian.Cnidarians have radial symme-try, tentacles, and stingingcells.

23. Sample answer: Cephalopodsneed to move rapidly to catchprey and to avoid predators.The lack of a bulky shell prob-ably helps them move quickly.Their advanced nervous systemprobably helps them movequickly, too.

24. Sample answer: The worms arenot grouped together becausethey have different characteris-tics. Annelid worms are seg-mented, while the others arenot. Annelid worms have aclosed circulatory system,whereas other worms do not.Flatworms have eyespots andsensory lobes, and the otherworms do not.

25. Sample answer: Butterfliesneed to find a mate when theyare ready to reproduce. Wingswould allow them to search fora mate in a broader area.

26. Sample answer: Earthwormsdig holes in soil and thus allowair to reach more parts of thesoil. They also digest parts ofthe soil and leave castings aswaste. The castings make thesoil rich. If a gardener removedall earthworms from a garden,the soil would not be as fertile.

Interpreting Graphics27. a: head; b: thorax; c: abdomen28. 629. the thorax (b)30. an insect

CHAPTER RESOURCES


CRF • Chapter Reviewg• Chapter Test Ag• Chapter Test Ba• Chapter Test Cs• Vocabulary Activityg

Workbooks

Study Guide• Study Guide is also available in Spanish.

Chapter 15 • Chapter Review 405

READING

MISCONCEPTIONALERT

READINGRead each of the passages below. Then, answer the questions that follow each passage.

Passage 1 Giant squids are very similar to their smaller relatives. They have a torpedo-shaped body, two tentacles, eight arms, a mantle, and a beak. All of their body parts are much larger, though. A giant squid’s eye may be as large as a volleyball! Given the size of giant squids, it’s hard to imagine that they have any enemies in the ocean, but they do.

Toothed sperm whales eat giant squids. How do we know this? Thousands of squid beaks have been found in the stomach of a single sperm whale. The hard beaks of giant squids are indigestible. Also, many whales bear ring marks on their forehead and fins that match the size of the suckers found on giant squids.

1. Based on the passage, what do you think the word indigestible describes?

A something that cannot be digestedB something that causes indigestionC something that one cannot dig outD something that one cannot guess

2. What can you infer from this passage?

F Giant squids only imagine that they have enemies.

G A toothed sperm whale can eat 10,000 giant squids in one meal.

H Giant squids defend themselves against toothed sperm whales.

I Giant squids and sperm whales compete with each other for food.

3. How are giant squids different from other kinds of squids?

A Giant squids have a torpedo-shaped body, a mantle, and a beak.

B Giant squids have enemies in the ocean.C Giant squids have larger body parts.D Giant squids are the size of a volleyball.

Passage 2 Water bears are microscopic inverte-brates that are closely related to arthropods. Most water bears live on wet mosses and lichens. Some of them eat roundworms and other tiny animals, but most feed on mosses. What makes water bears unique is their ability to shut down their body processes. They do this when their environment becomes too hot, too cold, or too dry. Shutting down body processes means that the organism doesn’t eat, move, or breathe. But it doesn’t die, either. It just dries out. When conditions improve, the water bear returns to normal life. Scientists think that the water bear’s cells become coated with sugar when its body shuts down. This sugar may keep the cells from breaking down while they are inactive.

1. How do scientists think sugar helps water bears survive while their body processes are shut down?

A Sugar coats their cells, keeping the cells from breaking down.

B Sugar coats their cells, trapping moisture inside the cells.

C Sugar coats their cells, keeping moisture from entering the cells.

D Sugar provides water bears with nutrients.

2. What do water bears eat?

F sugarG mossesH lichensI arthropods

3. Which is a unique characteristic of water bears?

A They are related to arthropods.B They often live on mosses or lichens.C They can live at the bottom of the ocean.D They can shut down their body processes

without dying.


Passage 11. A2. H3. C

Question 2: Students who choose answer F may have misread the last sentence of the first paragraph, which states that it is hard to imagine that giant squids have enemies. Students who choose answer G may be con-fused by the third sentence in the sec-ond paragraph, which mentions that thousands of beaks have been found in the stomach of a single sperm whale. While the passage does imply that squids and sperm whales fight each other, the implication is that squids defend themselves from sperm whales (answer H) rather than that squids and sperm whales fight each other in competition for food (answer I). The correct answer is H.

Passage 21. A2. G3. D

Question 3: Although all four answers state characteristics of water bears, the only unique characteristic is provided in answer D. The pas-sage clearly states this idea in the fourth sentence: “What makes water bears unique is their ability to shut down their body processes.”

Teacher’s NoteTeacher’s NoteTo provide practice under more realistic testing conditions, give students 20 minutes to answer all of the questions in this Standardized Test Preparation.

Answers to the standardized test preparation can help you identify student misconcep-tions and misunderstandings.

Standardized

Test P

reparation

The bar graph below shows the number of monarchs in a population from 1990 to 1994. Use the graph to answer the ques-tions that follow.

Read each question below, and choose the best answer.

1. Compare the number of butterfl ies in the population during 1990, 1991, 1992, and 1993. Identify the statement that best describes how the population changed during those years.

A The population increased.B The population remained the same.C The population decreased.D The population doubled yearly.

2. Why might butterfl y scientists be surprised about the 1994 monarch population?

F The 1994 population was the fi rst population of 9 million ever recorded.

G The 1994 population was the fi rst decreased population recorded in 4 years.

H The 1994 population was the fi rst increased population recorded in 4 years.

I The 1994 population was the fi rst decreased population ever recorded.

3. What can you infer from the graph about how the monarch’s environmental conditions changed between 1993 and 1994?

A Conditions were worse in 1994.B Conditions did not change between 1993

and 1994.C Conditions were better in 1994.D This graph does not contain enough

information to determine how conditions changed between 1993 and 1994.

4. What was the average population of monarchs during these 5 years?

F 7 millionG 8 millionH 9 millionI 40 million

1. Raymond wanted to arrange his shell collection in order of size. Which group of shell lengths is listed in order from smallest to largest?

A 1.6 cm, 0.25 dm, 0.017 m, 5.0 cmB 0.017 m, 0.25 dm, 1.6 cm, 5.0 cmC 1.6 cm, 5.0 cm, 0.25 dm, 0.017 mD 1.6 cm, 0.017 m, 0.25 dm, 5.0 cm

2. Raquelle wants to buy some earthworms to put in her garden. The earthworms are sold in containers that each hold 8 worms. How many containers will Raquelle need to buy if she wants 75 earthworms?

F 9 containersG 10 containersH 15 containersI 83 containers

3. Maxwell found a huge basket star while he was scuba diving. The basket star had fi ve arms, and each arm branched into three pieces. Each of these pieces branched into two more tips. How many tips did the basket star have?

A 2 tipsB 5 tipsC 15 tipsD 30 tips

INTERPRETING GRAPH ICS

Monarch Butterfly Population

Num

ber of

mon

arch

s (in millions

)

0

1

2

3

4

5

6

7

8

9

10

1990 1991 1992 1993 1994

Year

MATH

Chapter 15 • Standardized Test Preparation 407

INTERPRETING GRAPHICS1. A

2. G3. D4. G

Question 2: Students who answer this question incorrectly may be con-fused by having to take into account that the graph shows only 5 years of data. We cannot assume that any part of the graph is the only time such data were ever recorded. Therefore, answers F and I cannot be true. Answer H is incorrect because it states that the population decreases rather than increases. So, the correct answer is G.

MATH1. D2. G3. D

Question 1: Students who are confused by this question may find converting all of the numbers into the same unit helpful. If all of the numbers are listed in centimeters, it becomes clear that answer D is the only onethat shows the lengths arranged from smallest to largest.

CHAPTER RESOURCES


CRF • Standardized Test Preparation g

State Resources

For specifi c resources for your state, visit go.hrw.com and type in the keyword HSMSTR.

in Action

in Action

Language ArtsThe words crustacean and crust both come from the same Latin root—crusta. Think of how crustaceans are similar to crusts, and then guess the meaning of the Latin root.Math

Measure the widest and narrowest parts of the leech in the photo. Calculate how many times wider the wide part is than the narrow part. Which end of the leech do you think is the head? Why do you think so?

Science, Technology, and SocietyLeeches to the RescueBloodsucking leeches may sound scary, but they could save your toes! Leeches are used in operations to reattach lost limbs, fingers, or toes. During these operations, doctors can reconnect arteries, but not small veins, which are more delicate. As a result, blood flow in the limb, finger, or toe is impaired. The tissues may become full of loose blood. If this happens, the tissues of the reattached parts die. But if leeches suck the extra blood from the reattached part, the tissues can remain healthy until the veins grow back.

Weird ScienceA Powerful PunchThe mantis shrimp packs a powerful punch! This animal is nick-named “killer shrimp” and “thumb-splitter.” These crustaceans can be divided into two groups: the smashersand the spearers. The smashers have large front limbs that they use to club their prey with great speed and power. They can easily smash through the shells of clams, snails, and crabs. Larger species have been known to break double-walled aquarium glass! The spearers have sharp spines on their front limbs, and lash out with incredible speed—at about 1,000 cm/sec. That is one of the fastest animal movements known!

Science, Technology,

and Society

Discussion --------------------------------- GENERAL

Tell students that for centuries, physicians used leeches to remove blood from patients in a process called bloodletting. The physicians thought that an excess of blood in the body was responsible for several illnesses, including head-aches, fevers, and heart disease. Supposedly, the leeches would remove the bad blood from a patient’s body. However, this idea was discredited in the late 1800s. Ask students to brainstorm how people may have realized that ill-ness was not caused by excess blood in the body. Discuss how science depends on challenging old ideas and testing new ideas.

Weird Science

BackgroundThe forelimbs of the mantis shrimp usually stay strong and intact despite their violent and repetitive usage. One reason that the forelimbs stay strong is that they undergo a periodic molt, which replaces their shell. Also, the forelimbs of the “smashers” are especially thick and calcified. When a mantis shrimp is found to be missing a forelimb, the problem is usually due to another mantis shrimp rather than to a feeding accident.

Answer to Math Activity

The widest part of the leech is about 2.7 cm and its narrowest part is about 0.5 cm. So, 2.7 cm �0.5 cm � 5.4. The wide part is about 5.4 times wider than the narrow part. Accept all reason-able answers about which end of the leech is the head. Two important parts of the answer are that the student may use the measurements as a basis for an answer and that the student dem-onstrates some rational basis for the answer.

Answer to Language Arts Activity

Sample answer: A crust is a hard covering on bread, and a crustacean has a hard exoskeleton surrounding its body. So, the root crusta prob-ably refers to a hard covering.


Social StudiesOne ctenophore from the United States took over both the Black

Sea and the Sea of Azov by eating small fish and other food. This crowded out big-ger fish, changing the ecosystem and ruining the fisheries. Write a paragraph about how Matsumoto’s work as a marine biologist could help solve problems like this one.

To learn more about these Science in Action topics, visitgo.hrw.com and type in thekeyword HL5INVF.

Check out Current Science®

articles related to this chapter by visiting go.hrw.com. Just type in the keyword HL5CS15.

George MatsumotoMarine Biologist Dr. George Matsumoto is a marine biologist at the Monterey Bay Aquarium in California. A seventh-grade snorkeling class first sparked his interest in ocean research. Since then, he’s studied the deep seas by snorkeling, scuba diving, and using research vessels, remotely operated vehicles (ROVs), and deep-sea submersibles. On the Johnson Sea Link submersible, he traveled down to 1,000 m (3,281 ft) below sea level!

Marine biology is a field full of strange and wonderful creatures. Matsumoto focuses on marine invertebrates, particularly the delicate animals called comb jellies. These invertebrates are beautiful animals that have not been studied very much. Comb jellies are also called ctenophores (TEN uh FAWRZ),which means “comb-bearers.” They have eight rows of cilia that look like the rows of a comb. These cilia help ctenophores move through the water. By studying ctenophores and similar marine invertebrates, Matsu-moto and other marine scientists can learn about the ecology of ocean communities.

WRITINGSKILL

Chapter 15 • Science in Action 409

Careers

vv--------------------------------------------------- GENERAL

If your town or a neighboring town has an aquarium, arrange a class field trip to the aquar-ium. Be sure to ask a scientist at the aquarium to talk to students about careers in marine biology. If you aren’t close to an aquar-ium, have the class visit the Monterey Bay E-quarium on the Internet. Ask each student to read about the marine science careers on this Web site. Have students pick the career that most interests them and write a short report about that career.

Answer to Social Studies Activity

Sample answer: Marine biologists who study ctenophores could think of ways to control the foreign ctenophores that were disrupting the Black Sea and Sea of Azov ecosystems. For example, scientists such as Matsumoto may know how to remove the ctenophores, how to balance ctenophore populations by protecting natural ctenophore predators that live in the Black Sea and Sea of Azov, or how to stop the transfer of ctenophores from the United States to the Black Sea and Sea of Azov.

Documents

15 Invertebrates Compression guide: Chapter Planning Guide · 2013. 3. 4. · Section 4 Echinoderms •Describe the endoskeleton, nervous system, and water vascular system of echinoderms