Unit 1 What Is Biology? What Is Advance Planning · reproduction species growth development...

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Unit Projects

Unit ProjectsUnit ProjectsUnit Projects

Unit 1Unit 1Advance PlanningChapter 1■ Purchase preserved mildew or

collect mildew samples forMiniLab 1-1.

■ Purchase specially markedpackages of Quaker Oatmealfor MiniLab 1-3.

■ Order or collect pill bugs andother materials for the BioLab.

■ Prepare leaning plants for theGetting Started Demo.

■ Obtain a culture of mealwormsfor the Assessment activity.

Tape ProductionVisual-Spatial Have students use avideo camera to make a tape about

living things in your area. Students maytape the same area through the seasonsto show changes.

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Make a ModelKinesthetic Students can make athree-dimensional model that

depicts the kinds of living things foundin your area. Alternatively, students canmodel another area, such as a rain forest.

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Final ReportHave students present their group’s find-ings in oral reports that could be under-stood by students at your local middleschool. L3

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What IsBiology?What IsBiology?

Biologists seek answers to questions aboutliving things. For example, a biologistmight ask how plants, such as sunflowers,convert sunlight into chemical energy thatcan be used by the plants to maintain lifeprocesses. Biologists use many methods toanswer their questions about life. Duringthis course, you will gain an understandingof the questions and answers of biology, andhow the answers are learned.

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UNIT CONTENTSUNIT CONTENTS

Biology: The Study of Life

UNIT PROJECTUNIT PROJECT

Use the Glencoe Science Web Site for more project

activities that are connected to this unit.www.glencoe.com/sec/science

Unit 1Unit 1

What Is Biology?BIODIGESTBIODIGEST

Unit ProjectsUnit ProjectsUnit Projects

Unit Projects

Unit 1Unit 1

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What Is Biology?

Unit OverviewThis unit includes one chapterthat introduces students to thenature, excitement, and methodsof biology. Students are firstintroduced to the characteristicsof living organisms. The natureof science and the methods of sci-ence are then discussed by usingexamples intended to spark stu-dent interest as they attempt toanswer questions and solve prob-lems concerning the world of life.

Introducing the UnitAsk students to look at the photoand describe some of the adapta-tions of sunflowers that makethem successful. Tell studentsthat they will learn in this unithow to identify the characteristicsof all living organisms, includingsunflowers. Explain to studentsthat during their studies in thiscourse they will use the methodsof science described later in thechapter.

Discover the Diversity ofLiving ThingsHave students do one of the projects for thisunit as described on the Glencoe Science WebSite. As an alternative, students can do one ofthe projects described on these two pages.

DisplayVisual-Spatial Students can usephotographs or illustrations from

magazines and science journals to makea collage showing as many different living things as possible in the availabletime.

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Pond StudyVisual-Spatial Have student groupsstudy a local pond or stream to find

out what living organisms are present.Students may wish to make drawings ortake photos to illustrate their findings.

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http://www.glencoe.com/sec/science

Index to National Geographic MagazineThe following articles may be used forresearch relating to this chapter.“The Rise of Life on Earth,” by RichardMonastersky, March 1998.“Life Grows Up,” by Richard Monastersky,April 1998.

Teacher’s Corner

2B

Biology: The Study of LifeBiology: The Study of Life

TransparenciesReproducible MastersSection

What Is Biology?

The Methods of Biology

The Nature of Biology

Section 1.1

Section 1.2

Section 1.3

Teacher Classroom Resources

Section Focus Transparency 1



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Assessment Resources Additional ResourcesSpanish ResourcesEnglish/Spanish AudiocassettesCooperative Learning in the Science ClassroomLesson Plans/Block Scheduling

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Chapter Assessment, pp. 1-6MindJogger VideoquizzesPerformance Assessment in the Biology ClassroomAlternate Assessment in the Science ClassroomComputer Test BankBDOL Interactive CD-ROM, Chapter 1 quiz

Chapter 1 OrganizerChapter 1 Organizer

MATERIALS LIST

BioLabp. 26 Armadillidium (pill bug), watchor clock, petri dish, paper, pencil, met-ric ruler, Internet access

MiniLabsp. 6 mildew sample, microscope,microscope slide, coverslip, dropper,water, paper, pencilp. 14 microscope slides, dropper,water, isopropyl alcohol, alcohol test-ing solution, personal hygiene productsor cosmetics, wax pencil, paper, pencilp. 23 artificial dinosaur eggs (2),

stirring rods (2), beakers (2), cold andboiling water, paper, pencil

Alternative Labp. 12 small jars or beakers (2), graduated cylinder, caffeinated coffee,decaffeinated coffee, labels, pencil

Quick Demosp. 7 Lithops plantp. 12 sugar cube, ashes, matchesp. 15 assorted scientific journalsp. 22 pine needles or leaves, metricruler, paper, pencil

Key to Teaching StrategiesKey to Teaching Strategies

Level 1 activities should be appropriatefor students with learning difficulties.Level 2 activities should be within theability range of all students.Level 3 activities are designed for above-average students.ELL activities should be within the abilityrange of English Language Learners.

Cooperative Learning activitiesare designed for small group work.These strategies represent student prod-ucts that can be placed into a best-workportfolio.These strategies are useful in a blockscheduling format.

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Need Materials? Contact Carolina Biological Supply Company at 1-800-334-5551or at http://www.carolina.com

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Activities/FeaturesObjectivesSection

What Is Biology?National Science EducationStandards UCP.2; A.1, A.2;C.1, C.3, C.4, C.5, C.6; E.1,E.2; F.3, F.4, F.6; G.1 (1/2 session)

The Methods ofBiologyNational Science EducationStandards UCP.2; A.1, A.2;B.2; C.6; F.4, F.5; G.1, G.2(1 session, 1/2 block)

The Nature of BiologyNational Science EducationStandards UCP.2; A.1, A.2;E.1, E.2; F.3, F.4, F.5; G.1,G2 (1 session, 1 block)

1. Recognize some possible benefits fromstudying biology.

2. Summarize the characteristics of livingthings.

3. Compare different scientific methods.4. Differentiate among hypothesis, theory,

and principle.

5. Compare and contrast quantitativeand descriptive research.

6. Explain why science and technologycannot solve all problems.

MiniLab 1-1: Predicting Whether Mildew isAlive, p. 6Careers in Biology: Nature PreserveInterpreter, p. 8Internet BioLab: Collecting Biological Data,p. 26

MiniLab 1-2: Testing for Alcohol, p. 14Focus On Scientific Theories, p. 16Problem-Solving Lab 1-1, p. 18Inside Story: Scientific Methods, p. 19

Problem-Solving Lab 1-2, p. 22MiniLab 1-3: Hatching Dinosaurs, p. 23Biology & Society: Organic Food: Is ithealthier? p. 28

Section 1.2

Section 1.1

Section 1.3

Refer to pages 4T-5T of the Teacher Guide for an explanation of the National Science Education Standards correlations.

Reinforcement and Study Guide, pp. 1-2BioLab and MiniLab Worksheets, p. 1Concept Mapping, p. 1Critical Thinking/Problem Solving, p. 1 Content Mastery, pp. 1-2, 4

Reinforcement and Study Guide, p. 3BioLab and MiniLab Worksheets, pp. 3-4Laboratory Manual, pp. 1-4Tech Prep Applications, pp. 1-2Content Mastery, pp. 1, 3-4

Reinforcement and Study Guide, p. 4BioLab and MiniLab Worksheets, pp. 5, 7-8Content Mastery, pp. 1, 3-4Laboratory Manual, pp. 5-8 L2

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The following multimedia resources are available from Glencoe.

Biology: The Dynamics of LifeCD-ROM

Video: Biologist at WorkVideo: How Organisms InteractVideo: Adapted For SurvivalVideo: BioengineeringExploration: Interpreting Data

Videodisc ProgramBiologist at WorkHow Organisms InteractBioengineering

The Infinite VoyageThe Keepers of EdenUnseen Worlds

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http://www.carolina.com

Section

The Science of BiologyPeople have always been curious

about living things—how many dif-ferent species there are, where theylive, what they are like, how theyrelate to each other, and how theybehave. These and many other ques-tions about life can be answered. Theconcepts, principles, and theoriesthat allow people to understand thenatural environment form the core ofbiology, the study of life. What willyou, as a young biologist, learn aboutin your study of biology?

A key aspect of biology is simplylearning about the different types ofliving things around you. With all

the facts in biology textbooks, youmight think that biologists haveanswered almost all the questionsabout life. Of course, this is not true.There are undoubtedly many lifeforms yet to be discovered; millionsof life forms haven’t even beennamed yet, let alone studied. Life onEarth includes not only the commonorganisms you notice every day, butalso distinctive life forms that haveunusual behaviors.

When studying the different typesof living things, you’ll ask what, why,and how questions about life. Youmight ask, “Why does this livingthing possess these particular fea-tures? How do these features work?”

1.1 WHAT IS BIOLOGY? 3

How far do monarch butter-flies travel during theirannual migration? Why do

viceroy butterflies look so much likemonarchs? The natural world oftenposes questions like these. Usually,such questions have simple explana-tions, but sometimes the studyof biology reveals startlingsurprises. Whether nature’spuzzles are simple or complex,many can be explained usingthe concepts and principlesof biological science.

SECTION PREVIEW

ObjectivesRecognize some possible benefits fromstudying biology.Summarize the characteristics of livingthings.

Vocabularybiologyorganismorganizationreproductionspeciesgrowthdevelopmentenvironmentstimulusresponsehomeostasisenergyadaptationevolution

1.1 What Is Biology?

OriginWORDWORD

biologyFrom the Greekwords bios, meaning“life,” and logos,meaning “study.”Biology is the studyof life.

Monarch butterfly(above) and Viceroybutterfly (inset)

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Section 1.1

BIOLOGY: The Dynamics of Life SECTION FOCUS TRANSPARENCIES

Use with Chapter 1,Section 1.1

What are some characteristics of living organisms?

Which of these characteristics does each object have?

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Transparency Characteristics of Life1 SECTION FOCUS

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PrepareKey ConceptsIn this section, students learnthat biology is an organized studyand that many questions remainunanswered. The characteristicsthat living things share in com-mon are presented in relationshipto the themes of biology.

Planning■ Purchase a Lithops plant from a

nursery for the Quick Demo.■ Gather materials needed for

the Activity on page 7.

1 FocusBellringer Before presenting the lesson, display Section Focus Trans-parency 1 on the overhead pro-jector and have students answerthe accompanying questions.

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Assessment PlannerAssessment PlannerPortfolio Assessment

Portfolio, TWE, pp. 4, 7, 9, 17, 18, 23Alternative Lab, TWE, pp. 12-13

Performance AssessmentAssessment, TWE, pp. 8, 13Alternative Lab, TWE, pp. 12-13BioLab, TWE, pp. 26-27MiniLab, TWE, pp. 6, 14, 23MiniLab, SE, pp. 6, 14, 23

Knowledge AssessmentSection Assessment, SE, pp. 10, 20, 25Chapter Assessment, TWE, pp. 29-31

Skill AssessmentAssessment, pp. 10, 20, 22, 25Problem-Solving Lab, pp. 18, 22BioLab, SE, p. 27

2 BIOLOGY: THE STUDY OF LIFE

Biology: The Study of Life

What You’ll Learn■ You will identify the charac-

teristics of life.■ You will recognize how scien-

tific methods are used tostudy living things.

Why It’s ImportantRecognizing life’s characteristicsand the methods used to studylife provide a basis for under-standing the living world.

Testing an ObservationObserve leaning plants in a potand infer why you think theymay have grown this way. Howcould you test your inference?

To find outmore about

the characteristics of livingthings, visit the Glencoe ScienceWeb Site.www.glencoe.com/sec/science

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GETTING STARTEDGETTING STARTED

ChapterChapter

The plants and animals of this forest exhibit allthe characteristics of life.The mushrooms, and theunseen bacteria living in the soil and leaf litterof the forest floor, alsoshare the basic character-istics of life.

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Theme DevelopmentStudents are introduced to sixmajor themes of biology: sys-tems and interactions, home-ostasis, the nature of science,unity within diversity, evolu-tion, and energy. These themesare presented as the characteris-tics of life are discussed and thenature of science and scientificmethods are explained.

Chapter 1Chapter 1

MultipleLearningStyles

Look for the following logos for strategies that emphasize different learning modalities.

Kinesthetic Meeting IndividualNeeds, p. 5; Activity, p. 7Visual-Spatial Getting StartedDemo, p. 2; Portfolio, pp. 4, 7, 9;

Concept Development, p. 4; Micro-scope Activity, p. 9; Project, p. 24

Interpersonal Cultural Diversity,p. 8; Meeting Individual Needs,

p. 14; Project, p. 19

Linguistic Biology Journal, pp. 4, 9, 16, 18; Portfolio, p. 17Logical-Mathematical Tying toPrevious Knowledge, p. 13;

Portfolio, p. 23Naturalist Quick Demo, p. 22

GETTING STARTED DEMOGETTING STARTED DEMO

Visual-Spatial Prepareleaning plants by placing

them near a brightly lit win-dow several days before stu-dents arrive. The morningbefore students come to class,mix the leaning plants withstraight plants on a table wellaway from the window.Challenge students to explainwhy some plants lean and oth-ers do not.

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If time does not permit teach-ing the entire chapter, use theBioDigest at the end of theunit as an overview.

Resource ManagerResource Manager

Section Focus Transparency 1and Master

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living things depend upon other livingand nonliving things in a variety ofways and for a variety of reasons.

Biologists Study theDiversity of Life

Many people study biology simplyfor the pleasure of learning about theworld of living things. As you’veseen, the natural world is filled withexamples of living things that can beamusing or amazing, and that chal-lenge one’s thinking. Through yourstudy of biology, you will come toappreciate the great diversity ofspecies on Earth and the way eachspecies fits into the dynamic patternof life on our planet.

Biologists study the interactionsof the environment

Because no species, includinghumans, can exist in isolation, thestudy of biology must include theinvestigation of interactions amongspecies. For example, learning abouta population of wild rabbits wouldrequire finding out what plants theyeat and what animals prey on them.The study of one species alwaysinvolves the study of other specieswith which it interacts.

Human existence, too, is closelyintertwined with the existence ofother organisms living on Earth.Plants and animals supply us withfood and with raw materials likewood, cotton, and oil. Plants alsoreplenish the essential oxygen in theair. The students in Figure 1.3 arestudying organisms that live in a localstream. Activities like this help pro-vide a thorough understanding of liv-ing things and the intricate web ofnature. It is only through suchknowledge that humans can expect tounderstand how to preserve thehealth of our planet.

Biologists study problems and propose solutions

The future of biology holds manyexciting promises. Biological researchcan lead to advances in medical treat-ment and disease prevention inhumans and in other species. It canreveal ways to help preserve speciesthat are in danger of disappearing,and solve other problems, includingthe one described in Figure 1.4. Thestudy of biology will teach you howhumans function and how we fit inwith the rest of the natural world. Itwill also equip you with the knowl-edge you need to help sustain thisplanet’s web of life.


Figure 1.3By understanding theinteractions of livingthings, you will bebetter able to impactthe planet in a posi-tive way.

Figure 1.4Honeybees and manyother insects areimportant to farmersbecause they polli-nate the flowers ofcrop plants, such asfruit trees. In the1990s, populations of many pollinatorsdeclined, raising wor-ries about reducedcrop yields.

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The answers to such questions leadto the development of general bio-logical principles and rules. Asstrange as some forms of life such asthose shown in Figure 1.1 mayappear to be, there is order in thenatural world.

Biologists study the interactions of life

One of the most general principlesin biology is that living things do notexist in isolation; they are all function-ing parts in the delicate balance ofnature. As you can see in Figure 1.2,


Figure 1.1Few of the creatures you readabout in works of fantasy andfiction are as unusual as someof the organisms that actuallylive on Earth.

Figure 1.2Questions about livingthings can sometimesbe answered only byfinding out about theirinteractions with theirsurroundings.

The seahorse iswell hidden in itsenvironment. Itsbody shape blendsin with the shapesof the seaweeds inwhich it lives.

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The spadefoot toad burrowsunderground and encasesitself in a waterproof envelope to prevent waterloss during extended periodsof dry weather.

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Leaves of the insect-eating pitcher plantform a tube lined withdownward-pointinghairs that preventinsects from escaping.Trapped insects fall intoa pool of water anddigestive juices at thebottom of the tube.

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Orcas, also known as killer whales, arehighly intelligentmarine mammals thatlive and hunt in socialunits called pods.

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Leaf-cutter ants feed onfungus. They carry bits ofleaves to their nest, thenchew the bits and formthem into moist balls onwhich the fungus grows.

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PortfolioPortfolio

Identifying HabitatsVisual-Spatial Provide studentswith pictures of unusual organisms.

Ask them to speculate on the type ofhabitat in which each might live. Havethem explain their reasoning and placetheir pictures and habitat descriptions intheir portfolios.

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BIOLOGY JOURNAL BIOLOGY JOURNAL

Investigating New Life FormsLinguistic Ask students to find outabout some of the most recent dis-

coveries of new species. Ask them toreport in their journals about how andwhere these new life forms were discov-ered and who discovered them. Askthem to discuss the significance of eachdiscovery.

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MEETING INDIVIDUAL NEEDS MEETING INDIVIDUAL NEEDS

Learning DisabledKinesthetic Have students make aweb from string to illustrate the

intricate web of nature. On the web, havestudents place index cards and picturesthat illustrate organisms common to yourarea and their needs for life.

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CD-ROMBiology: The Dynamicsof Life

Video: Biologist at WorkDisc 1

VIDEODISCBiology: The Dynamicsof Life

Biologist at Work (Ch. 2)Disc 1, Side 128 sec.!7@Ä"

2 TeachVisual LearningFigure 1.1 Ask students to discussother strange creatures they haveread about or seen on television.Explain that even with such diver-sity, all living things have certaincharacteristics in common.

Concept DevelopmentVisual-Spatial Take studentsaround the school grounds.

Ask them to list in their note-books all the different kinds oforganisms they observe. Theyshould indicate the characteristicsthey used to categorize eachorganism as a living thing.

DisplayMake a bulletin board displaythat shows unusual structural andbehavioral adaptations of plantsand animals.

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Video: How Organisms InteractDisc 1


How Organisms Interact (Ch. 4)Disc 1, Side 1, 40 sec.

!7TÇ"The Infinite Voyage The Keepers of EdenExtinction and the NationalZoo’s Tamarin Monkey Project(Ch. 4), 13 min. 30 sec.

!7KVF"Preserves of Endangered Species:San Diego and Kenya (Ch. 8)8 min. 30 sec.

!7s~D"

EnrichmentVisual-Spatial Explain thatlife is found in some unex-

pected places. Ask students tobring in samples of dustballsfrom their homes. Have themseal each sample in a plastic baglabeled with the location fromwhich it was taken. Studentsshould then examine the dustballsunder the microscope for dustmites. Ask them to compare thenumbers of mites in samplesfrom various locations.

Revealing MisconceptionsStudents often think that allplants found in an area are nativeto that area. Point out that manyplants may have been importedfrom other areas. For example,oats and rye imported fromEurope have become establishedin California at the expense ofnative grasses.

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Living things are organizedWhen biologists search for signs of

life, one of the first things they lookfor is structure. That’s because theyknow that all living things show anorderly structure, or organization.

The living world is filled withorganisms. All of them, including theearthworm pictured in Figure 1.6,are composed of one or more cells.Each cell contains the genetic mater-ial, or DNA, that provides all theinformation needed to control theorganism’s life processes.

Although living things are verydiverse—there may be five to tenmillion species, perhaps more—theyare unified in having cellular organi-zation. Whether an organism is madeup of one cell or billions of cells, allof its parts function together in anorderly, living system.

Living things make more living things

One of the most obvious of all thecharacteristics of life is reproduction,the production of offspring. The litter of mice in Figure 1.7 is just one example. Organisms don’t live

forever. For life to continue, theymust replace themselves.

Reproduction is not essential forthe survival of an individual organ-ism, but it is essential for the contin-uation of the organism’s species(SPEE sheez). A species is a group oforganisms that can interbreed andproduce fertile offspring in nature. Ifindividuals in a species never repro-duced, it would mean an end to thatspecies’ existence on Earth.


Figure 1.6Like all organisms,earthworms aremade up of cells. Thecells form structuresthat carry out essen-tial functions, such asfeeding or digestion.The interaction ofthese structures andtheir functions resultin a single, orderly,living organism.

Figure 1.7A variety of mecha-nisms for reproduc-tion have evolvedthat ensure the con-tinuation of eachspecies. Some organ-isms, including mice,produce many off-spring in one life-time.

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ActivityKinesthetic Give smallgroups of students the fol-

lowing materials: a squash seed, abottle of bubbles and a bubblewand, a fresh fruit such as atomato, a cut flower in a test tubefilled with water, and a warmingcandle in a jar lid. Light the can-dle for each group and instructstudents to observe the flame.Next, instruct them to blow a fewbubbles. Ask them to observeeach of the other objects. Havestudents decide whether or noteach item is alive and explain thereasons for their decisions.Discuss responses as a class. Youmay find it necessary to distin-guish between nonliving thingsand once-living or dead things aspart of the discussion. Studentswill probably know that bubbles andwarming candles are not alive, butbecause they move, students may saythey are alive.

Visual LearningFigure 1.7 Ask students to giveexamples of organisms they knowabout that have many young andthose that have few. For example,fish have many young and ele-phants have few. Bring studentsto the realization that, normally,the larger the organism, thefewer young it produces and thelonger the period between births.

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Characteristics of Living Things

Most people feel confident thatthey can tell the difference between aliving thing and a nonliving thing, butsometimes it’s not so easy. In identify-ing life, you might ask, “Does it

move? Does it grow? Does it repro-duce?” These are all excellent ques-tions, but consider a flame. A flamecan move, it can grow, and it can pro-duce more flames. Are flames alive?

Biologists have formulated a list ofcharacteristics by which we can rec-ognize living things. Sometimes,nonliving things have one or more oflife’s characteristics, but only whensomething has all of them can it beconsidered living. Anything that pos-sesses all of the characteristics of lifeis known as an organism, like theplants shown in Figure 1.5. All livingthings have an orderly structure, pro-duce offspring, grow and develop,and adjust to changes in the environ-ment. Practice identifying the char-acteristics of life by carrying out theMiniLab on this page.


Predicting Whether Mildew is Alive What is mildew? Is it alive? We see it “growing” on plastic shower curtains or on bathroom grout. Does it show the characteris-tics associated with living things?

Procedure! Copy the data table below.

@ Predict whether or not mildew is alive. Record your prediction in the data table under “First Prediction.”

# Obtain a sample of mildew from your teacher. Examine it for life characteristics. Make a second prediction andrecord it in the data table along with any observed lifecharacteristics. CAUTION: Wash hands thoroughly afterhandling the mildew sample.

$ Following your teacher’s directions, prepare a wet mountof mildew for viewing under the microscope. CAUTION:Use caution when working with a microscope, micro-scope slides, and cover slips.

% Are there any life characteristics visible through the microscope that you could not see before? Make a thirdprediction and include any observed life characteristics.

Analysis 1. Describe any life characteristics you observed.2. Compare your three predictions and explain how your

observations may have changed them. 3. Explain the value of using scientific tools to extend your

powers of observation.

MiniLab 1-1MiniLab 1-1

Prediction Life characteristics

First

Second

Third

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Data TableFigure 1.5These plants are called Lithops from theGreek lithos, meaning “stone.” Althoughthey don’t appear to be so, Lithops arejust as alive as elephants. Both speciespossess all of the characteristics of life.

Mildew

Observing

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PurposeStudents will look at mildewunder the microscope and decideif it is living.

Process Skillspredict, compare and contrast,observe and infer

Teaching Strategies■ Prior to the activity, ask howmany students believe mildew isliving/not living. Post the resultson the chalkboard. Poll studentsagain after the MiniLab andcompare both sets of responses.■ Scrape mildew samples fromshower grout or plastic showercurtains and bring them to class.Store samples in water to preventthem from drying out. CAU-TION: If live specimens areused, seal them in a plastic bagto protect students who might beallergic to mildew spores.■ Preserved mildew is availablefrom biological supply housesand can be used in place of livespecimens.■ Instruct students on properuse of microscope and micro-scope slides.■ Demonstrate the technique formaking a wet mount. Includeproper handling and cleaning ofcover glasses and glass slides.

Expected ResultsStudents may initially predictthat mildew is not alive. Duringmicroscopic examination, stu-dents will see long filaments(hyphae) and tiny circular objects(spores). Some students may seespores enclosed in a spore sac.

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MiniLab 1-1MiniLab 1-1 Quick DemoQuick Demo

Show students a Lithops plantand ask how they might deter-mine whether it is living or nonliving.

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Characteristics of LifeVisual-Spatial Set up stations aroundthe classroom with living and nonliving

items, such as a rock with lichen, bird’s nest,skeleton, potted plant, piece of uncookedsteak, strands of hair, drop of pond waterwith protozoans or algae focused on a

microscope slide, potato, peanut, stalk of celery, seeds, goldfish in a bowl, and otherinteresting material you may have in yourarea. Ask students to go from one station tothe next and decide if the specimens are orever were alive. Have students justify theiranswers in their portfolios.

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PortfolioPortfolioAnalysis1. organization, reproduction, growth,

adjusting to environment2. Answers will vary, depending on the

observations made by individual stu-dents.

3. Certain life characteristics could nothave been seen without the use of amicroscope.

Performance Have students designan experiment to determine if commercialproducts reduce or kill mildew as claimed.Use the Performance Task Assessment Listfor Designing an Experiment in PASC,p. 23. L2

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AssessmentAssessment


Concept Mapping, p. 1

BioLab and MiniLab Work-sheets, p. 1 L2

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many other factors. For example, thefox in Figure 1.9 feeds on small ani-mals such as rabbits and mice. Thefox responds to the presence of a rab-bit by quietly moving toward it, thenpouncing. Trees adjust to cold, drywinter weather by losing their leaves.Any condition in the environmentthat requires an organism to adjust isa stimulus. A reaction to a stimulusis a response.

The ability to respond to stimuli inthe environment is an importantcharacteristic of living things. It’s oneof the more obvious ones, as well.That’s because many of the structuresand behaviors that you see in organ-isms enable them to adjust to theenvironment. Try the BioLab at theend of this chapter to find out moreabout how organisms respond toenvironmental stimuli.

Regulation of an organism’s inter-nal environment to maintain condi-tions suitable for its survival is calledhomeostasis (hoh mee oh STAY sus).Homeostasis is a characteristic of lifebecause it is a process that occurs in allliving things. In addition to respond-ing to external stimuli, living things

respond to internal changes. Forexample, organisms must make con-stant adjustments to maintain the cor-rect amount of water and minerals intheir cells and the proper internal tem-perature. Without this ability to adjustto internal changes, organisms die.

Living things reproduce themselves,grow and develop, respond to exter-nal stimuli, and maintain homeostasisby using energy. Energy is the abilityto do work. Organisms get theirenergy from food. Plants make theirown food, whereas animals, fungi,and other organisms get their foodfrom plants or from organisms thatconsume plants.

Living things adapt and evolveAny structure, behavior, or inter-

nal process that enables an organismto respond to stimuli and better sur-vive in an environment is called anadaptation (ad ap TAY shun).

Adaptations are inherited from pre-vious generations. There are alwayssome differences in the adaptations ofindividuals within any population of organisms. As the environmentchanges, some adaptations are more


Figure 1.9Living things respond to stimuli and makeadjustments to environmental conditions.

By dropping their leaves in the fall,these trees conserve water and avoidfreezing during winter.

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Keen senses ofsmell and hearingenable a fox tofind prey. Furallows foxes andother mammals to regulate bodytemperature.

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9

CAREERS IN BIOLOGY

Nature PreserveInterpreter

I f you like people as much as youlove nature, you can combine

your skills and interests in a careeras a nature preserve interpreter.

Skills for the JobInterpreters are also called natu-

ralists, ecologists, and environmentaleducators. They might work for a naturepreserve or a state or national park, where they give talks,conduct tours, offer video presentations, and teach specialprograms. Some interpreters are required to have a degree inbiology, botany, zoology, forestry, environmental science,education, or a related field. They must also be skilled in com-municating with others.

Many interpreters begin as volunteers who have nodegrees, just a love of what they do. Over time, volunteersmay become interns, and eventually be hired. Interpretersoften help restore natural habitats and protect existing ones.Part of their job is to make sure visitors do not harm thesehabitats.

For example, many tidepool organisms find protectionfrom too much sunlight by crawling under rocks. A naturalistcan explain the importance of replacing rocks exactly as theywere found.

For more careers in related fields, be sureto check the Glencoe Science Web Site.

www.glencoe.com/sec/science


Figure 1.8All life begins as a singlecell. As cells multiply, each organism grows anddevelops and begins to take on the characteristicsthat identify it as a memberof a particular species.

Living things change during their lives

An organism’s life begins as a singlecell, and over time, it grows and takeson the characteristics of its species.Growth results in an increase in theamount of living material and theformation of new structures.

All organisms grow, with differentparts of the organism growing at differ-ent rates. Organisms made up of onlyone cell may change little during theirlives, but they do grow. On the otherhand, organisms made up of numerouscells go through many changes duringtheir lifetimes, such as the changes thatwill take place in the young nestlingsshown in Figure 1.8. Think aboutsome of the structural changes yourbody has already undergone since youwere born. All of the changes thattake place during the life of an organ-ism are known as its development.

Living things adjust to their surroundings

Organisms live in a constant inter-face with their surroundings, orenvironment, which includes the air,water, weather, temperature, anyother organisms in the area, and

8

DiscussionLead students in a discussion ofgeneral developmental stages ofvarious organisms. Examplesinclude complete and incom-plete metamorphosis in insects, or birth, infancy, childhood,puberty, adulthood, old age, anddeath in humans.

Career PathCourses in high school:biology, speech, language

arts, history, and computer skillsCollege: a degree in biology,forestry, education, or a relatedfield preferred

Career IssueNature interpreters and othersinvolved in protecting the envi-ronment recognize the conflictbetween the needs of humans andthose of plants, animals, andother nonhuman organisms. Askstudents to identify and discusssuch a conflict they know about,such as wetlands or forest preser-vation, or the debate aboutwhether or not whaling should bepermitted.

For More InformationFor more information aboutenvironmental careers, studentscan contact:

Environmental CareersOrganization

286 Congress Street, Third FloorBoston, MA 02210-1038

Performance Assessmentin the Biology Classroom, p. 1,Brine Shrimp Life Functions. Havestudents carry out this activity toobserve brine shrimp carrying outsome of their life functions.

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CAREERS IN BIOLOGY

Cultural DiversityThe History of Biological Discovery

Interpersonal Have students work ingroups of three or four and do basic

library research to prepare a presentationabout the history of biological science in aparticular country. Student presentations caninclude a chronology of important biologicalscience discoveries in the country, or they can

be more specific accounts of a particulararea of research. Presentations shouldinclude names of important scientists, detailsabout the area of research, and how theresearch may have benefited society.Encourage students to incorporate posters,models, photographs, or videos in their pre-sentations.

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No More LightLinguistic Ask students to write ascience fiction story about what

might happen if Earth stopped gettingenergy from sunlight. Remind them thattemperatures would decrease and photo-synthesis would stop.

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PortfolioPortfolio

Stimulus and ResponseVisual-Spatial Have students cutfive pictures from magazines that

show organisms responding to stimuli. Askstudents to mount each picture on a cleansheet of paper and label the stimulus andresponse. Have students place theirlabeled illustrations in their portfolios.P

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Video: Adapted for SurvivalDisc 2

VIDEODISCThe Secret of LifeCamouflage:

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Camouflage: Spider Clip

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DiscussionDiscuss with students ways inwhich the human body maintainshomeostasis. Sweating and shiver-ing are two homeostatic mechanismsfor maintaining body temperature.

Microscope ActivityVisual-Spatial Have studentsrefer to the Skill Hand-

book to review the proper proce-dures for caring for and using amicroscope. Then ask them toexamine prepared slides of fertil-ization and development in a vari-ety of organisms, such as a chick,sea urchin, frog, or mammalembryo. Make sure students un-derstand that all these organismsdeveloped from the union ofsperm and egg.

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The BioLab at theend of the chaptercan be used at thispoint in the lesson.

INTERNETINTERNET


suited to the new conditions thanothers. Individuals with more suit-able adaptations are more likely tosurvive and reproduce. As a result,individuals with these adaptationsbecome more numerous in the popu-lation. Figure 1.10 shows someexamples of adaptation.

The gradual accumulation of adap-tations over time is evolution (ev uhLEW shun). Clues to the way the pre-sent diversity of life came about maybe understood through the study of

evolution. In later chapters of thisbook, you will study how the theoryof evolution can help answer many ofthe questions people have about liv-ing things.

As you learn more about Earth’sorganisms in this book, reflect on thegeneral characteristics of life. Ratherthan simply memorizing facts aboutorganisms or the vocabulary terms,try to see how these facts and vocab-ulary are related to the characteristicsof living things.


Section AssessmentSection Assessment

Understanding Main Ideas1. What are some important reasons for studying

biology?2. Explain the difference between a stimulus and

a response and give an example of each. How do these terms relate to an organism’s internalenvironment?

3. Why is energy required for living things? How do living things obtain energy?

4. How are evolution and reproduction related?

Thinking Critically5. How are energy and homeostasis related in living

organisms?

6. Observing and Inferring Suppose you discoveran unidentified object on your way home fromschool one day. What characteristics would youstudy to determine whether the object is a livingor nonliving thing? For more help, refer toThinking Critically in the Skill Handbook.

SKILL REVIEWSKILL REVIEW

Figure 1.10Living things adapt to their envi-ronments in a variety of ways.

Rotifers are microscopicorganisms that create awater current with theirwheels of cilia. They feedon microscopic food parti-cles brought in with the current.

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The desert Octillo has leaves for onlya few days after a good rain. Thisadaptation helps conserve water.

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Many nocturnal animals, such as thisowl, possess largeeyes for efficientvision at night.

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Magnification:100�

ReteachHave students draw a diagram toillustrate how the pupil of the eyeresponds to bright light. Studentscan observe this homeostaticmechanism in the classroomusing flashlights or lamps.

ExtensionAsk students working in groupsto investigate the latest develop-ments in robotics. Have them listthe characteristics of robots andcompare and contrast these char-acteristics with those of livingorganisms. Have them point outkey characteristics that distin-guish robots as nonliving.

Skill Ask students to ex-plain how they would test to seewhich color of light would cause abean plant to grow fastest.

4 CloseDemonstrationShow slides and photographs thatillustrate the six major themes ofbiology. Discuss each theme as aclass.

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Reinforcement and StudyGuide, pp. 1-2

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living things, or to appreciate the diver-sity of species and the way each fits intothe dynamic patterns of life on Earth

2. A stimulus is anything in the environ-ment that requires an organism toadjust. The adjustment made is theresponse. Sweating in humans is a

response to the stimulus of high tem-perature.

3. Energy is required for organisms tocarry on all life processes. Organismssuch as plants obtain energy from sun-light, but most organisms obtain theirenergy by consuming living or deadorganisms.

4. Reproduction provides the variability

among organisms that is required forevolution in a species.

5. Energy is necessary to maintain home-ostasis.

6. Examine its organization and see if it is cellular or not; see if it grows, ordevelops; see if it responds to stimuli oradapts to a change in its environment;see if it maintains homeostasis.10

Section

Observing andHypothesizing

Curiosity is often what motivatesbiologists to try to answer simplequestions about everyday observa-tions, such as why earthworms leavetheir burrows after it rains.Earthworms obtain oxygen throughtheir skin, and will drown in water-logged soil. Sometimes, answers toquestions like these also provide bet-ter understanding of general biologi-cal principles and may even lead topractical applications, such as the dis-covery that a certain plant can beused as a medicine. The knowledgeobtained when scientists answer onequestion often generates other ques-tions or proves useful in solvingother problems.

The methods biologists useTo answer questions, different

biologists may use many differentapproaches, yet there are some stepsthat are common to all approaches.The common steps that biologistsand other scientists use to gatherinformation and answer questions arescientific methods.

Scientists often identify problemsto solve—that is, questions to ask andanswer—simply by observing theworld around them. For example, alaboratory scientist who is investigat-ing questions about the reproductionof pea plants may come up with anew question about their develop-ment. Or, a scientist may ask a ques-tion about the feeding habits ofprairie dogs after first observingprairie dog behavior in the field.

1.2 THE METHODS OF BIOLOGY 11

Why do earthworms crawlonto sidewalks after itrains? Why do mosses grow

only in wet, shady areas? Biologistsask questions like these every day.Different approaches may be used toanswer different questions. Scientistswho discovered that earthwormscrawl out of rain-soaked soil to avoiddrowning used different methodsfrom those who learned that mossesrequire water for reproduction. Yet all scientific inquiries share somemethods in common.

SECTION PREVIEW

ObjectivesCompare different sci-entific methods.Differentiate amonghypothesis, theory, andprinciple.

Vocabularyscientific methodshypothesisexperimentcontrolindependent variabledependent variablesafety symboldatatheory

1.2 The Methods of Biology

Mosses are tiny plants thatgrow in dense clumps.

11

Section 1.2

PrepareKey ConceptsStudents study the methods usedin scientific investigations. Theyidentify the methods as theyrelate to problems in variousareas of biology.

Planning■ Obtain several kinds of cough

syrup and mouthwash to testin MiniLab 1-2.


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What is being tested in this experiment?

How could you improve the experimental setup?

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What is a controlled experiment? Some experiments involve two

groups: the control group and theexperimental group. The control isthe group in which all conditions arekept the same. The experimentalgroup is the test group, in which allconditions are kept the same exceptfor the single condition being tested.

Suppose you wanted to learn howbacteria affect the growth of differentvarieties of soybean plants. Yourhypothesis might state that the pres-ence of certain bacteria will increasethe growth rate of each plant variety.An experimental setup designed totest this hypothesis is shown inFigure 1.12. Bacteria are present onthe roots of the experimental plants,but not the controls. All other condi-tions—including soil, light, water,and fertilizer—are held constant forboth groups of plants.

Designing an experimentIn a controlled experiment, only

one condition is changed at a time.The condition in an experiment that ischanged is the independent variable,because it is the only variable thataffects the outcome of the experi-ment. In the case of the soybeans, the presence of bacteria is the inde-pendent variable. While changingthe independent variable, the scien-tist observes or measures a secondcondition that results from thechange. This condition is the dependent variable, because anychanges in it depend on changesmade to the independent variable. Inthe soybean experiment, the depen-dent variable is the growth rate of theplants. Controlled experiments aremost often used in laboratory settings.

However, not all experiments arecontrolled. Suppose you were on agroup of islands in the Pacific that isthe only nesting area for a large sea

bird known as a waved albatross,shown in Figure 1.13. Watching thenesting birds, you observe that thefemale leaves the nest when her mateflies back from a foraging trip. Thebirds take turns sitting on the eggsor caring for the chicks, often fortwo weeks at a time. You mighthypothesize that the birds fly in cir-cles around the island, or that theyfly to some distant location. To testone of these hypotheses, you mightattach a satellite transmitter to someof the birds and record their travels.An experiment such as this, which


Figure 1.12This experimenttested the effect ofbacteria on thegrowth of severalvarieties of soybeans.For each experimentthere are three rowsof each variety. Thecenter rows are theexperimental plants.The outer rows arethe controls.

Figure 1.13The waved albatross is alarge bird that nests onlyon Hood Island in theGalapagos Islands. Bytagging the birds withsatellite transmitters, scientists have learnedwhere these birds travel.

Visual LearningFigure 1.13 Ask students toexplain how a satellite transmitteris useful in tracking waved alba-trosses. Because albatrosses fly longdistances over open ocean, a trans-mitter is useful because it can contin-uously relay information that wouldbe difficult or impossible to attain inany other way.

Tying to PreviousKnowledge

Logical-Mathematical Presentthe following hypothesis to

your students: “If yeast is living,then it will be composed of cells.”Ask students to: (a) Describe anexperimental procedure thatcould be used to verify the hypo-thesis. Observe yeast under themicroscope. (b) Describe reasoningthat was used to form the hypoth-esis. Yeast cells require food and giveoff carbon dioxide gas. All livingmatter is composed of cells.

Performance Give stu-dents a sample of mealworms andoatmeal. Ask them to write thefollowing terms on their paper,leaving several lines between eachterm: observations, hypothesis,experiment, data, conclusion. Tellstudents to write in the spaces asthey try to determine the lifecycle of a mealworm. L1

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5. Make daily observations of your jarsfor one week. Check for the presenceof mold.

6. Record your observations in a suitabledata table by making diagrams of thecoffee liquid surfaces.

Analysis 1. Which type of coffee allows mold to

grow? both

2. Was your hypothesis supported by yourdata? will depend on hypothesis

3. What was the control, independentvariable, and dependent variable?decaffeinated coffee, caffeinated cof-fee, mold growth

Portfolio Have students write areport of their experimental findings.Ask them to record any other questionsthat arose during this experiment andexplain how they might be answered.Use the Performance Task AssessmentList for Lab Report in PASC, p. 47.


13

The question of brown tree snakes

Have you ever been told that youhave excellent powers of observation?This is one trait that is required ofbiologists. The story of the browntree snake in Figure 1.11 serves as anexample. During the 1940s, thisspecies of snake was accidentallyintroduced to the island of Guamfrom the Admiralty Islands in thePacific Ocean. In 1965, it wasreported in a local newspaper that thesnake might be considered beneficialto the island because it is a predatorthat feeds on rats, mice, and othersmall rodents. Rodents are often con-sidered pests because they carry dis-ease and contaminate food supplies.

Shortly after reading the newspa-per report, a young biologist walkingthrough the forests of Guam made animportant observation. She notedthat there were no bird songs echoingthrough the forest. Looking into thetrees, she saw a brown tree snakehanging from a branch. After learningthat the bird population of Guam haddeclined rapidly since the introduc-tion of the snake, she hypothesizedthat the snake might be responsible.

A hypothesis (hi PAHTH us sus) is anexplanation for a question or a prob-lem that can be formally tested.Hypothesizing is one of the methodsmost frequently used by scientists. Ascientist who forms a hypothesis mustbe certain that it can be tested. Untilthen, he or she may propose sugges-tions to explain observations.

As you can see from the brown treesnake example, a hypothesis is not arandom guess. Before a scientistmakes a hypothesis, he or she hasdeveloped some idea of what theanswer to a question might bethrough personal observations, exten-sive reading, or previous experiments.

After stating a hypothesis, a scien-tist may continue to make observa-tions and form additional hypothesesto account for the collected data.Eventually, the scientist may test ahypothesis by conducting an experi-ment. The results of the experimentwill help the scientist draw a conclu-sion about whether or not thehypothesis is correct.

ExperimentingPeople do not always use the word

experiment in their daily lives in thesame way scientists use it in theirwork. As an example, you may haveheard someone say that he or she wasgoing to experiment with a cookierecipe. Perhaps the person is planningto substitute raisins for chocolatechips, use margarine instead of butter,add cocoa powder, reduce the amountof sugar, and bake the cookies for alonger time. This is not an experimentin the scientific sense because there isno way to know what effect any one ofthe changes alone has on the resultingcookies. To a scientist, an experimentis a procedure that tests a hypothesisby the process of collecting informa-tion under controlled conditions.


Figure 1.11Brown tree snakes(Boiga irregularis)were introduced toGuam more than 50years ago. Sincethen, their numbershave increased to apopulation of morethan a million andthey have severelyreduced the nativebird population ofthe island.

OriginWORDWORD

hypothesisFrom the Greekwords hypo, meaning“under,” and thesis,meaning a “plac-ing.” A hypothesisis a testable expla-nation of a naturalphenomenon.

2 TeachBrainstormingAsk students to brainstorm a listof questions they have that relateto biology. Write the questions asa list on the board. Allow stu-dents to give examples of howthey might find answers to theirquestions if they were givenaccess to any equipment or tech-nology they can imagine.

Using Scientific TermsAsk students to state a hypothesisabout some question. Point outthat a hypothesis is not a ques-tion, but rather a statement thatanswers a question.

Alternative LabConducting an Experiment

PurposeStudents will follow the steps of scientificmethods to solve a problem. The questionto be answered is, Will the caffeine presentin coffee prevent mold growth?

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PreparationHave students wear lab aprons, safety gog-gles, and disposable latex gloves, and washtheir hands after checking for mold growth.Some students may be allergic to moldspores.Materials2 small jars (baby food jars), graduatedcylinder, labels, caffeinated coffee, decaf-feinated coffee

ProcedureGive the following directions to students.

1. Form and record a hypothesis.2. Write your name and the date on the

labels. Write #1 on one label and #2 onthe other. Place the labels on the jars.

3. Add the following to each jar. Jar 1: 30mL caffeinated coffee; Jar 2: 30 mLdecaffeinated coffee.

4. Place both jars in the same location.

12

Quick DemoQuick Demo

Try to set a sugar cube on fireusing a lighted match. It doesnot burn. Rub the edge of thecube in ashes and attempt toignite it. It burns. Ask studentsto hypothesize why the cubeburns after it is rubbed inashes. Responses may includethat the ashes—not the sugarcube—burn, that the ashesserved as kindling, or that theashes catalyze, or speed up,the reaction between thesugar and the oxygen in air(burning). Ask students howthey might test their explana-tions. Responses might includetrying to set the ashes on fireseparately or exposing thesugar to a hotter flame for alonger time.

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about a danger that may exist fromchemicals, electricity, heat, or proce-dures you will use. Refer to the safetysymbols in Appendix C at the back ofthis book before beginning any labactivity in this text. It is your respon-sibility to maintain the highest safetystandards to protect yourself as wellas your classmates.

Data gatheringTo answer their questions about

scientific problems, scientists seekinformation from their experiments.Information obtained from experi-ments is called data. Sometimes, datafrom experiments are referred to asexperimental results.

Often, data are in numerical form,such as the distance covered in analbatross’s trip or the height that soy-bean plants grow per day. Numericaldata may be measurements of time,temperature, length, mass, area, vol-ume, or other factors. Numericaldata may also be counts, such as thenumber of bees that visit a flower per day or the number of wheat seeds that germinate at different soiltemperatures.

Sometimes data are expressed inverbal form, using words to describeobservations made during an experi-ment. Scientists who first observedthe behavior of pandas in Chinaobtained data by recording whatthese animals do in their naturalhabitat and how they respond totheir environment. Learning thatpandas are solitary animals with largeterritories helped scientists under-stand how to provide better care forthem in zoos and research centers.

Having the data from an experi-ment does not end the scientificprocess. Read the Focus On on thenext page to see how data collectionrelates to other important aspects ofresearch.


Sharp Object Safety This symbol appears when a danger of cuts or punctures caused by the use of sharp objects exists.

Clothing Protection Safety This symbol appears when substances used could stain or burn clothing.

Eye Safety This symbol appears when a danger to the eyes exists. Safety goggles should be worn when this symbol appears.

Chemical Safety This symbol appears when chemicals used can cause burns or are poisonous if absorbed through the skin.

Table 1.1 Safety symbols

Figure 1.14Biologists use manytools in their studies.

The gas chromatographcan measure pesticideresidues in plants orfishes.

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Gel electrophoresiscan be used to produce a DNA fingerprint asshown. ComparingDNA reveals howclosely related twospecies are.

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The optical micro-scope makes smalldetails visible.

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BrainstormingA student repeats an experimentseveral times and each timerecords different data. Have stu-dents offer possible reasons whyan experiment might yield differ-ent data for different trials.Reasons include failure to keep allfactors but one the same, errors in data recording, errors in mathe-matical treatment of the data, ornaturally occurring variability inexperimental outcome. L2

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Testing for Alcohol Commercials forcertain over-the-counter products maynot tell you that one of the ingre-dients is alcohol. How can youverify whether or not a certainproduct contains alcohol? Oneway is to simply rely on theinformation provided during a commercial. Another way is to experiment and find outfor yourself.

Procedure! Copy the data table.

@ Draw three circles on a glass slide. Label them A, B, and C.CAUTION: Put on safety goggles.

# Add one drop of water to circle A, one drop of alcohol tocircle B, and one drop of alcohol-testing chemical to circlesA, B, and C. CAUTION: Rinse immediately with water iftesting chemical gets on skin or clothing.

$ Wait 2-3 minutes. Note in the data table the color of eachliquid and the presence or absence of alcohol.

% Record the name of the first product to be tested.^ Draw a circle on a clean glass slide. Add one drop of the

product to the circle.& Add a drop of the alcohol-testing chemical to the circle.

Wait 2-3 minutes. Record the color of the liquid.* Repeat steps 5-7 for each product to be tested. CAUTION:

Wash your hands with soap and water immediately afterusing the alcohol testing chemical.

( Complete the last column of the data table. If alcohol is present, the liquid turns green, deep green, or blue. A yellow or orange color means no alcohol is present.

Analysis1. Explain the purpose of using the alcohol-testing chemical

with water, with a known alcohol, and by itself.2. Which products did contain alcohol? No alcohol?

MiniLab 1-2MiniLab 1-2has no control, is the type of biologi-cal investigation most often used infield work.

The experimental design that isselected depends on what otherexperimenters have done and whatinformation the biologist hopes togain. Sometimes, a biologist willdesign a second experiment evenwhile a first one is being conducted,if he or she thinks the new experi-ment will help answer the question.Try your hand at experimenting inthe MiniLab on this page.

Using toolsTo carry out experiments, scientists

need tools that enable them to recordinformation. The growth rate ofplants and the information from satel-lite transmitters placed on albatrossesare examples of important informa-tion gained from experiments.

Biologists use a wide variety oftools to obtain information in anexperiment. Some common toolsinclude beakers, test tubes, hotplates, petri dishes, thermometers,dissecting instruments, balances,metric rulers, and graduated cylin-ders. More complex tools includemicroscopes, centrifuges, radiationdetectors, spectrophotometers, DNAanalyzers, and gas chromatographs.Figure 1.14 shows some of thesemore complex tools.

Maintaining safety Safety is another important factor

that scientists consider when carryingout experiments. Biologists try tominimize hazards to themselves, thepeople working around them, andthe organisms they are studying.

In the experiments in this text-book, you will be alerted to possiblesafety hazards by safety symbols likethose shown in Table 1.1. A safetysymbol is a symbol that warns you


Alcohol presentColor of liquid

Circle A

Circle B

Circle C

Product name

Product name

Data Table

Experimenting

14

PurposeStudents will experiment todetermine which products con-tain alcohol.

Process Skillsdraw a conclusion, experiment,interpret data, observe and infer

Safety Precautions■ Review safety precautions

regarding goggles and the useof an acid solution.

Teaching Strategies■ For preparation instructionsfor the alcohol-testing reagent,see page 40T of the TeacherGuide. ■ Make circles on slides with aChina marking or eyebrow pen-cil. Students could use small testtubes rather than glass slides. Usecaution when cleaning glassware.■ For circle C, use isopropyl(rubbing) alcohol. Products to betested may include aftershavelotion, cough syrups, mouthwash.

Expected ResultsStudent data will vary with theproducts tested. Circle A willappear yellow-orange, circle Bgreen to blue, and circle C yel-low.

Analysis1. to determine which colors

indicate the presence orabsence of alcohol

2. Answers will depend onproducts tested.

Performance Provide stu-dents with several different typesof alcohol (rubbing, ethyl, meth-yl) and ask them to determinewhich types the alcohol-testingchemical can detect. Use thePerformance Task AssessmentList for Carrying Out a Strategyand Collecting Data in PASC,p. 25.

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Learning DisabledInterpersonal Group students appro-priately. Have them use scientific

methods to alter a cookie recipe. Ask stu-dents to name the control to be used, theindependent variable, and the dependentvariable.

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Bring copies of scientific jour-nals to class and allow studentsto examine them. Ask studentsto speculate as to which branchof science each journaladdresses.

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MMEETING EETING IINDIVIDUAL NDIVIDUAL NNEEDS EEDS MEETING INDIVIDUAL NEEDS

Hearing ImpairedInterpersonal Supply students with thefollowing data showing how many

seeds were germinated by three laboratorygroups over a three-day period. Group A hadtwo seeds germinate on day 1, four seeds onday 2, and four seeds on day 3. Group B had

one seed germinate on day 1, six on day 2,and five on day 3. Group C had two seedsgerminate on day 1, four on day 2, and threeon day 3. Have students work in groups toprepare a class histogram of the number ofseeds germinating each day for all threegroups.

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VIDEODISCThe Secret of LifeMicroscopy Segment

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FORMING THEORIES Bakker’s hypotheses—supported by data gathered byother paleontologists and by dinosaur bones, growth pat-terns, and behavior—prompted scientists to reexaminetheories about dinosaurs. Were some dinosaurs endothermsand others ectotherms? Did dinosaurs have their ownunique physiology resembling neither reptiles nor mam-mals? Scientific theories about dinosaurs continue toevolve as new fossils are discovered and new tools to studythose fossils are developed.

THINKING CRITICALLYIn the 1960s, paleontologist Robert Bakker (right)hypothesized that dinosaurs were not sluggishectotherms but fast-moving, land-dwellingendotherms—animals like birds and mammals.Bakker observed that many dinosaurs had feet andlegs built for life on land. If hadrosaurs had led asemiaquatic life, Bakker reasoned, their feet wouldhave been webbed with long, thin, widely spaced

toes. But hadrosaurs had short, stubby toes and feet, obviouslysuited for land. In addition to Bakker’s observations, studies of fos-silized stomach contents revealed that hadrosaurs dined on thecones and leaves of cycads (above) and other terrestrial plants.After considering these data carefully, Bakker proposed that manydinosaurs were quick, agile endotherms that roamed Earth’sancient landscape.

COLLECTING DATA To test his hypotheses, Bakker intensified his research ondinosaur skeletons and bone structure. He found reportsfrom the 1950s comparing thousands of cross sections ofdinosaur bones with those of reptiles, birds, and mammals.These reports noted that many dinosaur bones were lessdense than those of modern reptiles and riddled with chan-nels for blood vessels. In short, many dinosaur bones resem-bled those of endotherms not ectotherms. Bakker confirmedhis observations by collecting supporting evidence fromother sources.

1 APPLYING CONCEPTS Robert Bakker’s research led to a differenttheory regarding the physiology of dinosaurs. As new fossils are foundand new tools developed to study them, paleontologists will continue toreplace existing theories with newer ones. What are some reasons fora scientific theory to be changed?

EXPANDING Your View

BREAD PALM, CYCAD FAMILY

ROBERT BAKKER

DINOSAUR BONE SHOWINGCHANNELS FOR BLOOD VESSELSMagnification: 25 x

PALEONTOLOGIST WORKING ON FOSSIL

ROBERT BAKKER WITHBRONTOSAUR FEMUR

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MAKING HYPOTHESESReptiles are ectotherms—animals with body temperatures influenced

by their external environments. Early in the study of dinosaur fossils,many scientists assumed that because dinosaur skeletons resembled thoseof some modern reptiles, dinosaurs, too, must have been ectotherms. Thisassumption led scientists to conclude that many dinosaurs, being both hugeand ectothermic, were slow-growing, slow-moving, and awkward on land.

Because the most complete dinosaur skeletons occurred in rocks formedat the bottom of bodies of water, scientists hypothesized that dinosaurs

lived in water and that water helped to support their great weight. Whenskeletons of duck-billed dinosaurs, called hadrosaurs, were discovered, thishypothesis gained support. Hadrosaurs had broad, flat ducklike bills,which, scientists suggested, helped them collect and eat water plants.

IGUANODON

What is a scientific theory? Incasual usage, “theory” meansan unproven assumption abouta set of facts. A scientifictheory is an explanation of anatural phenomenon supportedby a large body of scientificevidence obtained from variousinvestigations and observa-tions. The scientific processbegins with observations of thenatural world. These observa-tions lead to hypotheses, datacollection, and experimentation.If weaknesses are observed,hypotheses are rejected ormodified and then tested againand again. When little evidenceremains to cause a hypothesisto be rejected, it may become atheory. Follow the scientific process described here that led to new theories about dinosaurs.

OBSERVINGPeople have been unearthingfossils for hundreds of years.The first person to reconstruct a dinosaur named it Iguanodon,meaning “iguana tooth,”because its bones and teethresembled those of an iguana.By 1842 these extinct animalswere named dinosaurs, meaning“terrible lizards.”

FOCUS ON

FIELD MUSEUM OF NATURAL HISTORY, CHICAGO

ScientificTheories

HADROSAUR

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Focus OnScientific TheoriesPurposeStudents will learn from exam-ples how theories are formedfrom repeated observations, com-parative studies, and discussionsamong scientists over manydecades.

Teaching Strategies■ Ask students to discuss whatthey know about dinosaurs. Askthem how they have learnedabout these amazing, extinct ani-mals.■ Have students put forwardtheir own ideas on how dinosaurslived from day to day. Ask them iftheir ideas are hypotheses, specu-lations, beliefs, or theories. Havethem begin to distinguish amongthese different ideas by askingthem to state in a complete sen-tence what they know aboutanother topic, such as computers.■ If possible, visit a dinosaur dis-play in a local museum, and havestudents make notes in their jour-nals about the different theoriesof dinosaur behavior explained inthe exhibits. L2

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A Dino-Bird?Linguistic A dinosaur fossil discov-ered in China appears to have had

downy feathers along its neck and back-bone. Ask students to hypothesize abouthow and why feathers first evolved. Havethem write down supporting evidence fortheir hypothesis.

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VIDEODISCVIDEOTAPEThe Secret of Life

On the Brink: Portraits ofModern Science

!7@Z'ULA"

New Research on DinosaursLinguistic Although Dr. Bakker’s boneevidence shows a link between dino-

saurs and endotherms, other researchers dis-pute this and point to factors, such as nasalcavities, that show dinosaurs were more likeectotherms. Have students research the

newest hypotheses about dinosaurs by read-ing recent articles in magazines. Ask them towrite a summary of the articles for theirportfolios and list the factors that supportboth ectothermy and endothermy as thehomeostatic mechanisms for dinosaurmetabolism.

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PortfolioPortfolio

VIDEODISCThe Infinite Voyage:The Great Dinosaur Hunt

Dinosaur Tracks: FootprintAnalysis (Ch. 6), 5 min.

Communication Theories (Ch. 9)5 min. 30 sec.


Exploration: Interpreting DataDisc 1

!7~$G"

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Visual LearningHave students study the art ofIguanodon and the hadrosaur.Have them list the structures thatsupport the hypotheses thathadrosaurs lived in water and onland.

Answers to Expanding YourView

1. Applying Concepts Scien-tific theories must be changedto accommodate new or con-flicting data.

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Scientific Methods

Scientific methods are used by scientists to answerquestions and solve problems. The development of

the cell theory, one of the most useful theories in biologi-cal science, illustrates how the methods of science work.In 1665, Robert Hooke first observed cells in cork.

Thinking Critically What is the function of other scien-tists in the scientific process?

Magnification: 30�

Cork cells as drawn by Robert Hooke

INSIDESSTORTORYY

INSIDE

Observing The first step toward scientificdiscovery takes place when a scientist observessomething no one has noticed before. AfterHooke’s discovery, other scientists observedcells in a variety of organisms.

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Making a hypothesis A hypothesis is a testableanswer to a question. In 1824, René Dutrochethypothesized that cells are the basic unit of life.

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Collecting data Data can support ordisprove a hypothesis. Over the years,scientists who used microscopes toexamine organisms found that cellsare always present.

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Forming a theoryA theory is a hypoth-esis that is supportedby a large body ofscientific evidence.By 1839, many scien-tific observationssupported thehypothesis that cellsare fundamental tolife. The hypothesisbecame a theory.

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Developing new hypotheses A new the-ory may prompt scientists to ask new ques-tions or form additional hypotheses. In 1833,Robert Brown hypothesized that the nucleusis an important control center of the cell.

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Revising the theory Theories are revised asnew information is gathered. The cell theorygave biologists a start for exploring the basicstructure and function of all life. Importantdiscoveries, including the discovery of DNA,have resulted.

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Publishing results Results ofan experiment are useful onlyif they are made available toother scientists. Many scientistspublished their observations ofcells in the scientific literature.

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IINSIDENSIDESSTORTORYY

INSIDE

PurposeStudents will review methodsused in scientific investigations.

Teaching Strategies■ Point out that not every scien-tific investigation uses everymethod, nor do all investigationslead to a published theory.■ Provide students with biologi-cal journals such as Nature orScientific American. Ask them toread the articles and identify themethods of science used.

Visual Learning■ Have students look at cork

cells through a microscope andcompare them with the photoon this page, then ask them tocompare the capabilities oftheir microscopes with the oneused by Robert Hooke.

Critical ThinkingOther scientists repeat the sameexperiment to validate originalresults. Scientists extend under-standing by performing experi-ments to answer related questions.

3 AssessCheck for UnderstandingProvide students with scientificmethods listed in a scrambledorder. Ask students to sequencesteps in the correct order.

ReteachAsk students to outline the stepsused in scientific methods. Foreach level of the outline, havethem provide an example takenfrom studies described in thetext. L2

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Are the claims valid? ”Our product is new and improved.” “Use this mouth wash and your mouth will feel clean all day.” Sound familiar? TV and radio commercials con-stantly tell us how great certain products are. Are these claims always based on facts?

AnalysisListen to or view a

commercial for a product that addresses a medical problem such as heartburn, allergies, or bad breath. If possible, tape the commercial so that you can replay it as often as needed. Record the following information:1. What is the major claim made in the commercial?2. Is the claim based on experimentation?3. What data, if any, are used to support the claim?

Thinking Critically1. In general, was the claim based on scientific methods?

Explain your answer.2. In general, are product claims made in commercials

based on experimental evidence? Explain your answer.

3. Describe a scientific experiment that could be conductedto establish claims made for the product in your commercial.

Problem-Solving Lab 1-1Problem-Solving Lab 1-1 AnalyzingInformation

Thinking about what happened Often, the thinking that goes into

analyzing experimental data takes thegreatest amount of a scientist’s time.After careful review of the results, thescientist must come to a conclusion:Was the hypothesis supported by thedata? Was it not supported? Aremore data needed? Data from anexperiment may be considered con-firmed only if repeating that experi-ment several times yields similarresults. To review how scientificmethods are carried out, read theInside Story.

After analyzing the data, most sci-entists have more questions than theyhad before the experiment. Theycompare their results and conclusionswith the results of other studies byresearching the published literaturefor more information. They alsobegin to think of other experimentsthey might carry out. Are all theclaims you hear on TV commercialsbased on data gathered by the scien-tific method? Find out by conductingthe Problem-Solving Lab here.

Reporting results Results and conclusions of experi-

ments are reported in scientific journals,where they are open to examinationby other scientists. Hundreds of sci-entific journals are published weeklyor monthly. In fact, scientists usuallyspend a large part of their time read-ing journal articles to keep up withnew information as it is reported.The amount of information pub-lished every day in scientific journalsis more than any single scientistcould read. Fortunately, scientistsalso have access to computer data-bases that contain summaries of sci-entific articles, both old and new.

Verifying resultsData and conclusions are shared

with other scientists for an importantreason. After results of an investiga-tion have been published, other sci-entists can try to verify the results byrepeating the experiment. If theyobtain similar results, there is evenmore support for the hypothesis.When a hypothesis is supported bydata from additional experiments, itis considered valid and is generallyaccepted by the scientific community.When a scientist publishes the resultsof his or her investigation, other sci-entists can relate their own work tothe published data.


18

PurposeStudents will analyze the claimsmade in a commercial.

Process Skillsanalyze information, draw a con-clusion, experiment, think criti-cally

Teaching Strategies■ You may wish to have theentire class analyze the samecommercial. Tape a specific com-mercial and play it back to theclass. Or provide students withthe printed dialogue from a radiocommercial.

Thinking Critically

1. Student answers will vary.Many commercials makeclaims without specifying anyscientific backing.

2. Student answers will vary.Many commercials do notuse experimental evidencebut base their claims oninference.

3. Students should describe a hypothesis, control, depen-dent and independent vari-ables, trials, data accumu-lation, and a conclusion basedon data.

Portfolio Ask students todesign a video commercial thatbases its claims on experimentaldata. Have them include theirdata and analyses as part of thecommercial. Use the Perform-ance Task Assessment List forVideo in PASC, p. 81. L2

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Problem-Solving Lab 1-1Problem-Solving Lab 1-1

P R O J E C TUsing Scientific Methods

Interpersonal Have students workin groups on a biological problem

they select, such as the behavior of a par-ticular species of bird, reptile, or mammalin your area. At the conclusion of the pro-ject, students should be able to explainthe methods of science they used.

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Field ResearchLinguistic Have students look in Dis-cover, National Geographic, or similar

publications to find an article that describesfield research. Ask them to write a report onthe article, contrasting the scientist’s work inthe field with the work the scientist had tocontinue back in the laboratory.

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Working as a Food ChemistLinguistic Tell students to imaginethey are the chief food chemist work-

ing in a candy factory. They are trying toimprove on the taste of a “Smacking GoodBar.” Have them describe some things theywould suggest to their staff to attempt, in acontrolled manner, to find a better candybar recipe.

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For example, biologists studyingthe behavior of elephants in Africapublished their observations. Otherscientists, who were studying ele-phant communication, used that datato help determine which of the ele-phants’ behaviors are related to com-munication. Further experimentsshowed that female elephants emitcertain sounds in order to attractmates, and that some of the sounds

produced by bull elephants warnother males away from receptivefemales, as described in Figure 1.15.

Theories and lawsPeople use the word theory in

everyday life very differently fromthe way scientists use this word. Youmay have heard someone say that heor she has a theory that a particularfootball team will win the SuperBowl this year. What the personreally means is that he or she believesone team will play better for somereason. Much more evidence isneeded to support a scientific theory.

In science, a hypothesis that is sup-ported by many separate observationsand experiments, usually over a longperiod of time, becomes a theory. Atheory is an explanation of a naturalphenomenon that is supported by alarge body of scientific evidenceobtained from many different investi-gations and observations. A theoryresults from continual verificationand refinement of a hypothesis.

In addition to theories, scientistsalso recognize certain facts of nature,called laws or principles, that aregenerally known to be true. The factthat a dropped apple falls to Earth isan illustration of the law of gravity.


Figure 1.15Experiments haveshown that male ele-phants communicatewith other malesusing threat posturesand low-frequencyvibrations that warnrival males away.


Understanding Main Ideas1. Suppose you made the observation that bees

seem to prefer a yellow flower that producesabundant amounts of pollen and nectar over apurple flower that produces less pollen and nec-tar. List two separate hypotheses that you mightmake about bees and flowers.

2. Describe a controlled experiment you could per-form to determine whether ants are moreattracted to butter or to honey.

3. What is the difference between a theory and ahypothesis?

4. Why do experiments usually require a control?

Thinking Critically5. Describe a way that a baker might conduct

a controlled experiment with a cookie recipe.

6. Interpreting Scientific Illustrations Reviewthe Inside Story. What happens when a hypothe-sis is not confirmed? What does the position ofthe word theory indicate about the strength of a scientific theory compared to the strength of ahypothesis? For more help, refer to ThinkingCritically in the Skill Handbook.


ExtensionHave students look up cell theoryin this text. Ask them to speculateabout the hypotheses that mayhave been made by each of thescientists who first discoveredcells.

Skill Provide each studentwith a piece of laboratory equip-ment. Have them list five obser-vations about the equipment andsuggest how the equipment mightbe used.

4 CloseDemonstrationDisplay laboratory equipmentand safety equipment and cloth-ing students will use in theirstudy of biology. For each item,identify its function and properuse. As a follow-up, set up labstations at which students arerequired to demonstrate theirknowledge of each item. L2

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Section AssessmentSection AssessmentSection Assessment1. Students might hypothesize that bees

prefer yellow flowers to purple flowersor that bees prefer flowers with moreabundant pollen.

2. Set up an experimental chamber.Within a specific amount of time, countand record how many ants move tobutter placed a specific distance from

the ants. Repeat several times. Repeatusing honey in place of the butter.

3. A hypothesis is a testable explanationfor a question. A theory is a refinedexplanation supported by many differ-ent experiments.

4. A control provides greater certaintythat observed results are not due tochance or other variables.

5. Prepare one batch of cookies (the con-trol) by following a recipe and anotherbatch of cookies (the experimentalgroup) by varying a single variable inthe recipe, such as amount of sugar.

6. A new, revised hypothesis is tested, orthe experiment may be changed.Theories are supported by the resultsof a variety of experiments.20

Section

Kinds of ResearchYou have learned that scientists use

a variety of methods to test theirhypotheses about the natural world.Scientific research can usually beclassified into one of two main types,quantitative or descriptive.

Quantitative researchBiologists sometimes conduct con-

trolled experiments that result incounts or measurements—that is,numerical data. These kinds ofexperiments occur in quantitative

research. The data are analyzed bycomparing numerical values.

Data obtained in quantitativeresearch may be used to make agraph or table. Graphs and tablescommunicate large amounts of datain a form that is easy to understand.Suppose, for example, that a biologistis studying the effects of climate onfreshwater life. He or she may countthe number of microscopic organ-isms, called Paramecium, that surviveat a given temperature. This study isan example of quantitative research.

1.3 THE NATURE OF BIOLOGY 21

Scientific study includeslearning many knownfacts about the world

around us. Biologists useknown facts to discover newproblems, make hypotheses,design experiments, inter-pret data, and draw conclu-sions. Biology is also anactive process that includesmaking observations andconducting experiments inthe laboratory and in thefield. Science is both a body of facts andideas and a process by which we come tounderstand the natural world.

SECTION PREVIEW

Compare and contrastquantitative anddescriptive research.Explain why scienceand technology cannotsolve all problems.

Vocabularyethicstechnology

1.3 The Nature of Biology

Biologists study thestructure of the humanbrain (top) and observeanimal behavior (inset).

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Section 1.3

Key ConceptsStudents differentiate betweenquantitative and descriptiveresearch methods. The role ofresearch and its application anduse by society as technology isexamined.

Planning■ Obtain materials for the Mini-

Lab.


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The person in the picture is measuring in cubits—anancient Egyptian measurement that equals the distancefrom a person’s elbow to the tip of the middle finger.What problems might occur if everyone used this unit?

What characteristics should a measurement system haveto make it accurate and easily understood by everyone?

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SECTION FOCUS

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Quantitative DataLinguistic Have students reviewarticles on biological research in

Scientific American, Science News,Newsweek, or local newspapers. Askstudents to write a short essay identify-ing the quantitative measurementstaken in each study and describing howthe measurements were taken. L2

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Resource ManagerResource ManagerReinforcement and Study Guide,

p. 4Section Focus Transparency 3 and

MasterContent Mastery, p. 1, 3-4Laboratory Manual, pp. 5-8 L2

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in multiples of tens or tenths of abasic unit by applying a standard setof prefixes to the unit. In biology, themetric units you will encounter mostoften are meter (length), gram(mass), liter (volume), second (time),and Celsius degree (temperature).For a thorough review of measure-ment in SI, see Practicing ScientificMethods in the Skill Handbook.

Descriptive research Do you think the behavior of the

animals shown in Figure 1.17 wouldbe easier to explain with numbers orwith written descriptions of what theanimals did? Observational data—that is, written descriptions of whatscientists observe—are often just asimportant in the solution of a scien-tific problem as numerical data.

When biologists use purely obser-vational data, they are carrying outdescriptive research. Descriptiveresearch is useful because some phe-nomena aren’t appropriate for quan-titative research. For example, how aparticular wild animal reacts toevents in its environment cannot eas-ily be illustrated with numbers.Practice your descriptive researchskills in the MiniLab on this page.


Hatching Dinosaurs “Dinosaur eggs” can be found in spe-cially marked packages of oatmeal. You will conduct an investi-gation to determine what causes these pretend eggs to hatch.

Procedure! Copy the data table below.

@ Observe the dinosaur eggs provided and record their characteristics in your table.

# Place an egg in each of two containers.$ Make a hypothesis about the water temperature that will

cause the eggs to hatch.% Pour boiling water into one container and cold water in

the other. Stir for one minute. Record your observations.

Analysis1. Infer whether heat or moisture was more important for

hatching eggs. 2. Design an experiment that would test either heat or mois-

ture as the variable. What kind of quantitative data willyou gather?

3. What will be your control?4. How many trials will you run and how many eggs will you

test? If time permits, conduct your experiment.

MiniLab 1-3MiniLab 1-3 Observing and Inferring

Hot water treatment

Before treatment

Appearanceafter one minute

Cold water treatment

Data Table

Penguins cannot fly.They use their wingsfor swimming in theoceans of the south-ern hemisphere.

AA

Figure 1.17Do you think these ani-mals behave in the sameway in zoos as they doin nature?

Toucans live in the rainforests of South America.

BB

PurposeStudents make observations andinferences and design an experi-ment that tests a hypothesis.Process Skillsobserve and infer, hypothesize,collect data, design an experimentSafety PrecautionsCaution students to be carefulwhen pouring boiling water.Teaching Strategies■ Provide each group of studentswith two “dinosaur eggs” fromspecially marked packages ofQuaker Oatmeal. Each servingpacket in the box contains about14 eggs.■ Ask students to explain whythis experiment would not bepossible with real eggs.Expected ResultsThe outer candy layer of a“dinosaur egg” melts away inboiling water in less than aminute, leaving a tiny dinosaur-shaped candy.Analysis

1. heat or moisture2. To test heat, students might

put eggs under a heat lamp.To test moisture, studentsmight place eggs in varioustemperatures of water.

3. Variable is heat or moisture.Control is the basis of com-parison for the tested condi-tion. Students could measure“hatching” time.

4. Use as many eggs and trialsas time permits.

Performance Have stu-dents conduct the experimentthey design. Use the PerformanceTask Assessment List for CarryingOut a Strategy and CollectingData in PASC, p. 25. L2

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What can be learned from a graph? One way to express information is to present it in the form of a graph. The amount of information available from a graph depends on the nature of the graph itself.

AnalysisStudy the graph at

right. Answer the ques-tions that follow and note the type of information that can and cannot be answered from the graph itself.

Thinking Critically1. Is there ever a year in high school when all students

are enrolled in physical education? Explain your answer.

2. Is there a relationship between the number of studentsenrolled in physical education and their year of highschool? Explain your answer.

3. Can you tell which states in the country have the largestnumber of students enrolled in physical education?

4. Based on the graph, can you explain why so few studentstake physical education in their senior year?

Problem-Solving Lab 1-2Problem-Solving Lab 1-2 Making andUsing Graphs

The data obtained from theParamecium study is presented as agraph in Figure 1.16. You can prac-tice using graphs by carrying out theProblem-Solving Lab on this page.

Measuring in the International System

It is important that scientificresearch be understandable to scien-tists around the world. For example,what if scientists in the United Statesreported quantitative data in inches,feet, yards, ounces, pounds, pints,quarts, and gallons? People in manyother countries would have troubleunderstanding these data because theyare unfamiliar with the English systemof measurement. Instead, scientistsalways report measurements in a formof the metric system called theInternational System of Measurement,commonly known as SI.

One advantage of SI is that thereare only a few basic units, and nearlyall measurements can be expressed inthese units or combinations of them.The greatest advantage is that SI, likethe metric system, is a decimal sys-tem. Measurements can be expressed


Num

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Temperature

Paramecium Survival RatesFigure 1.16This graph shows howmany paramecia surviveas the temperatureincreases.

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Male

Female

U.S. Students Enrolled in Physical Education

Source: Youth Risk Behavior Survey, 1995

Paramecium

Magnification: 65�

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2 Teach

PurposeStudents will analyze a graph anddetermine that the amount ofinformation obtained from agraph is limited.

Process Skillsacquire information, interpretdata, think critically

Teaching Strategies■ Review the terminology asso-ciated with graphs or refer stu-dents to the Skill Handbook.

Thinking Critically

1. No. No bar extends to the100% line.

2. The number of studentsenrolled in physical educationdeclines as students progressfrom freshman to senior year.

3. Data needed to answer thequestion are not supplied.

4. No. The graph does not pro-vide this information.

Skill Have students designa graph to illustrate why fewerseniors take physical education.Students can make up the ques-tions to be graphed and estimatethe number of ‘yes’ responses.Use the Performance Task Ass-essment List for Conducting aSurvey and Graphing the Resultsin PASC, p. 35. L2

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Problem-Solving Lab 1-2Problem-Solving Lab 1-2


Naturalist Provide stu-dents with a metric ruler

and a clump of pine needles.Ask them to make two lists ofobservations: one that describesthe needles with words andanother that uses measure-ments. Have students comparetheir lists with classmates.P

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Cultural DiversityUnits and Standards The SI system is used in 95% of the countriesin the world. It provides a standardized sys-tem of measurement that makes scientificcommunication easier. Many early systems ofmeasurement were not standardized. Theancient Egyptians used a unit called thecubit, which was based on the length of thearm from elbow to fingertips. Because sizes

of individuals varied, the size of the unit var-ied. In England, the foot was equal to thelength of the foot of the king. When a newking came to power, the length changedaccording to the size of his foot. Have stu-dents research measuring systems usedaround the world and create a visual displayof their findings. L3

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Making PredictionsLogical-Mathematical Ask stu-dents to carry out the following

activity. Have them predict the chance that acoin, when flipped, should come up heads.50% How many heads should appear if a coinis flipped 10 times? 1/2 x 10 or 5 How manyheads will appear if a coin is flipped 100times? 1/2 x 100 or 50 Ask them to carry out

the coin tosses and record their results. Havethem use the activity to explain in theirportfolios if scientists can predict the resultsof an experiment with 100% certainty. Havethem explain the advantage of using a largesample or many trials in an experiment.Large samples increase the likelihood thatthe sample is representative.

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Other scientists work in researchthat has obvious and immediateapplications. Technology (tek NAHL

uh jee) is the application of scientificresearch to society’s needs and prob-lems. It is concerned with makingimprovements in human life and theworld around us. Technology hashelped increase the production offood, reduced the amount of manuallabor needed to make products andraise crops, and aided in the reduc-tion of wastes and environmentalpollution.

The advance of technology hasbenefited humans in numerous ways,but it has also resulted in some seri-ous problems. For example, irriga-tion technology is often used to boostthe production of food crops. If irri-gation is used over too many years inone area, the soil may becomedepleted of minerals or the evapora-tion of the irrigation water may leavedeposits of mineral salts in the soil.Eventually the soil may become use-less for growing crops, as illustratedin Figure 1.19.

Science and technology will neveranswer all of the questions we ask,nor will they solve all of our prob-lems. However, during your study ofbiology you will have many of your

questions answered and you willexplore many new concepts. As youlearn more about living things,remember that you are a part of theliving world and you can use theprocesses of science to ask andanswer questions about that world.



Understanding Main Ideas1. Why is it important that scientific experiments be

repeated?2. Compare and contrast quantitative and descrip-

tive research.3. Why is science considered to be a combination of

fact and process?4. Why is technology not the solution to all scien-

tific problems?

Thinking Critically5. Biomedical research has led to the development

of technology that can keep elderly, very illpatients alive. How does the statement “Theresults of research aren’t good or bad; they justare,” apply to such research?

6. Making and Using Graphs Look at the graph in Figure 1.16. Why do you think the high-temperature side of the graph drops offmore sharply than the low-temperature side? For more help, refer to Organizing Informationin the Skill Handbook.


Figure 1.19One example of a possible harmful side effect of technology isthe deterioration of soil caused by irrigation. In the field shownhere, irrigation technology initially appeared to solve the prob-lem of low crop yield, but later caused a different problem—thebuildup of excess mineral salts that prevent crop growth.

3 AssessCheck for UnderstandingHave students provide an exam-ple of: quantitative research,descriptive research, a contribu-tion of technology, and an ethicalissue in science.

ReteachAsk students to prepare an out-line of the major concepts of thissection.

ExtensionLogical-Mathematical Havestudents research the idea of

“being able to beat cancer with astrong positive mental attitude.”Have them explain why it may bedifficult to evaluate scientificallyhow a positive mental attitudecontributes to recovery from dis-ease.

Skill Have students mea-sure their arm spans and palm widths in cen-timeters. Convert these

measurements to millimeters andmeters.

4 CloseDiscussionDescribe one possible benefit orspin-off that might come fromthe study of: how birds find theirway during migration; longerlasting batteries; bat echoloca-tion. L3

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Science and SocietyThe road to scientific discovery

includes making observations, formu-lating hypotheses, performing experi-ments, collecting and analyzing data,drawing conclusions, and reportingresults in scientific journals. No mat-ter what methods scientists choose,their research often provides societywith important information that canbe put to practical use.

Maybe you have heard peopleblame scientists for the existence ofnuclear bombs or controversial drugs.To comprehend the nature of sciencein general, and biology in particular,people must understand that knowl-edge gained through scientificresearch is never inherently good orbad. Notions of good and bad ariseout of human social, ethical, andmoral concerns. Ethics refers to themoral principles and values held byhumans. Scientists might not considerall the possible applications for theproducts of their research when plan-ning their investigations. Society as awhole must take responsibility for theethical use of scientific discoveries.

Can science answer all questions?

Some questions are simply not inthe realm of science. Such questionsmay involve decisions regarding goodversus evil, ugly versus beautiful, orsimilar judgments. There are also sci-entific questions that cannot betested using scientific methods.However, this does not mean thatthese questions are unimportant.

Consider a particular question thatis not testable. Some people assertthat if a black cat crosses your path,as shown in the cartoon in Figure1.18, you will have bad luck. On thesurface, that hypothesis appears to beone that you could test. But what isbad luck, and how long would youhave to wait for the bad luck tooccur? How would you distinguishbetween bad luck caused by the blackcat and bad luck that occurs at ran-dom? Once you examine the ques-tion, you can see there is no way totest it scientifically because you can-not devise a controlled experimentthat would yield valid data.

Can technology solve all problems?

Science attempts to explain howand why things happen. Scientificstudy that is carried out mainly forthe sake of knowledge—with noimmediate interest in applying theresults to daily living—is called purescience.

However, much of pure scienceeventually does have an impact onpeople’s lives. Have you ever thoughtabout what it was like to live in theworld before the development ofwater treatment plants, vaccinations,antibiotics, or high-yielding crops?These and other life-saving develop-ments are indirect results of researchdone by scientists in many differentfields over hundreds of years.

Figure 1.18If bad luck caused byblack cats occurred as reliably and asswiftly in real life asit does in cartoons, it really would be scientifically testable.

OriginWORDWORD

technologyFrom the Greekwords techne, mean-ing an “art or skill,”and logos, meaning“study.” Technologyis the application ofscience in our dailylives.

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EnrichmentHave students list quantitativeand descriptive data about fivecommon animals. Have thempresent their data to the class andhave the class use the data toidentify the animals beingdescribed. Ask which type of datawas most useful in attempting toidentify the animals and have stu-dents explain why. Quantitativedata such as size and number ofappendages may be too similar formany of the animals, whereasdescriptive data such as presence offur or feathers, common colors, anddescriptions of behavioral traits maybe more specific. L2

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Technological AdvanceHave student groups preparea report on one technologicaladvance that has had a directimpact on the life of one ofthe members of the group.P

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GiftedHave students list the heights oftheir classmates in centimeters. Ask

them to use their list to calculate averageheight, describe the range of heights,determine the most common height, andexplain whether the original data andcomputational results are descriptive orquantitative.

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P R O J E C TRecognizing Technology

Visual-Spatial Ask students to workin cooperative groups to prepare a

time line that shows the technologicaladvances in one area of biology, such asgenetics, biotechnology, or oceanography.

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Bioengineering (Ch. 37) Disc 1, Side 1, 57 sec.


Video: BioengineeringDisc 2

!:r}"

Section AssessmentSection AssessmentSection Assessment1. to see if the results are repeatable,

thus confirming their authenticity2. Quantitative research reports data in

numerical values based on measuring.Descriptive research reports data inwritten descriptions based on observa-tions.

3. A scientist needs a background of knowledge in his or her field. The

scientific process increases that knowl-edge.

4. Some problems do not have a scien-tific basis. Some technological solu-tions may pose more problems thanthey solve.

5. The biomedical researchers sought to increase knowledge. The applica-tion of the resulting technology is a

question society must answer.6. Paramecia die above a certain temper-

ature. This results in a rapid drop innumbers once this temperature isreached. They are better able to sur-vive as low temperatures rise, thus thegraph reflects this increased survival.

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graph “Pill Bug Length:Classroom Data.”

6. Go to the Glencoe Science WebSite at the address shown belowto post your data.

7. Gently touch the underside of thepill bug with a dull pencil point. It may be necessary to gently flipthe pill bug over with the pencilto get at its underside. CAUTION: Use care to avoidinjuring the pill bug.

8. Note its response and time, inseconds, how long the animalremains curled up. Record thetime in the data table as Trial 1.

9. Repeat steps 7-8 four more times,recording each trial in the datatable.

10. Calculate the average length oftime your pill bug remains curledup in a ball.

11. Post your data on the GlencoeScience Web Site.

12. Return the pill bug to yourteacher. CAUTION: Wash yourhands with soap and water afterworking with pill bugs.


1. Thinking Critically Explain howyou would define the term“orderly structure.” Explain howthis trait might also pertain tononliving things.

2. Using the Internet Explain howdata from the classroom andInternet graphs support the ideathat pill bugs grow and develop.

3. Interpreting Data What was themost common length of time pillbugs remained curled in responseto being touched?

4. Drawing a Conclusion Explainhow the response to being

ANALYZE AND CONCLUDEANALYZE AND CONCLUDE

Length in Millimeters1

10987654321

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Num

ber

of P

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Pill Bug Length: Classroom Data

Length in Millimeters1

100908070605040302010

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Num

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Pill Bug Length: Internet Data

Response Time in Minutes2

100908070605040302010

4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

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Average Pill Bug Response Time: Internet Data

touched is an adaptation.5. Experimenting How might you

design an experiment to deter-mine whether or not pill bugsreproduce?

Sharing Your DataSharing Your Data

Find this BioLab on theGlencoe Science Web Site

at www.glencoe.com/sec/science. Post yourdata in the data table provided for thisactivity. Use the additional data from otherstudents on the Internet, analyze the com-bined data, and complete your graphs.

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average data on the length of time in secondsthe pill bug remains rolled up. ■ Review the technique for preparing a histogram.

Data and ObservationsStudents should conclude that pill bugs showorganization, undergo growth and develop-ment, and adjust to their environment. Pill

bugs will remain rolled in a ball for approxi-mately 20 seconds. Typical length of amature pill bug is 10 mm.

Collecting BiologicalData

S eeing different life forms, and even interacting with them, is prettymuch part of a typical day. Petting a dog, swatting at a fly, cutting

the grass, and talking to your friends are common examples. But, haveyou ever asked yourself the question, “What do all of these different lifeforms have in common?” Let’s try to find out.

INTERNETINTERNET

ProblemWhat life characteristics can be

observed in a pill bug?

ObjectivesIn this BioLab, you will:■ Observe whether life characteristics

are present in a pill bug.■ Measure the length of a pill bug.■ Experiment to determine if a pill bug

responds to changes in its environ-ment.

■ Use the Internet to collect and com-pare data from other students.

Materialspill bugs, Armadillidiumwatch or classroom clockcontainer, glass or plasticpencil with dull pointrulercomputer with Internet connection

Safety PrecautionsAlways wear goggles in the lab.

Skill HandbookUse the Skill Handbook if you need

additional help with this lab.

PREPARATIONPREPARATION

1. Make copies of the data table andgraph outlines shown here.

2. Obtain a pill bug from yourteacher and place it in a smallcontainer.

3. Observe your pill bug to deter-mine whether or not it has anorderly structure. Record youranswer in the data table.

4. Using millimeters, measure andrecord the length of your pill bugin the data table.

5. Using your data and data fromyour classmates, complete the

PROCEDUREPROCEDURE

Time in secondsTrial

Response to environment

Orderly structure?

Pill bug length in mm

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Total

Average time

Organization and growth and development

Data Table

Time AllotmentOne class period

Process Skillscollect data, define operationally,experiment, observe and infer,acquire information, think criti-cally, communicate

Safety PrecautionsRemind students to treat live ani-mals gently and follow directionscarefully. Have students weargoggles, lab aprons, and dispos-able latex gloves.

■ Pill bugs—also called sowbugs, wood lice, or isopods—may be collected locally orpurchased from a biologicalsupply house. Armadillidiumvulgare is the only species thatwill roll tightly into a “pill,” soit is preferred for this activity.

1. Student answers will vary andmay include the following:shows organization; has spe-cific parts for certain jobs; allpill bugs look alike. Yes,orderly structure also appliesto nonliving things. Manynonliving things are orga-nized, including buildings,books, computers.

2. The graph shows that pillbugs vary in length, but mostreach a maximum size ofabout 10 mm.

3. Pill bugs remain curled for anaverage of approximately 20seconds.

4. The pill bug’s outer shell israther tough; rolling into aball could prevent predatorsfrom attacking its soft under-side and fragile appendages.

ANALYZE AND CONCLUDEANALYZE AND CONCLUDE

PREPARATIONPREPARATION

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PROCEDUREPROCEDURE

TroubleshootingStudents may have difficulty assessingwhether pill bugs show an orderly structure.Advise them to make a “best guess” toanswer this question.

Teaching Strategies■ Allow students to work in small groups oftwo or three.

■ Make sure that students have already cov-ered the section dealing with life character-istics before attempting this laboratoryactivity.■ Laboratory finger bowls or plastic dishesfrom supermarkets or fast food restaurantscan be used as small containers.■ Review the procedure for determining an average. Have students round off their


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5. Student answers will vary.Place several pill bugs in asealed container and add foodand moisture as needed.Observe pill bugs weekly andcompare numbers present tothose originally placed incontainer. Or, look for imma-ture forms that may appear inthe container.

Skill Ask students to pre-pare a graph of data that would berepresentative of the experimentalresults from “Sharing Your Data.”Refer students to Making andUsing Graphs in the Skill Hand-book. Use the Performance TaskAssessment List for Graph fromData in PASC, p.39. L2

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INTERNETINTERNET INTERNETINTERNET

Sharing Your DataSharing Your Data

To navigateto the

Internet BioLabs, choose theBiology: The Dynamics of Lifeicon at the Glencoe ScienceWeb Site. Click on the studentsite icon, then the BioLabs icon.To expand this activity, havestudents design and conductan experiment to determine ifpill bugs have preferences forcertain food types. L2

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Chapter 1 AssessmentChapter 1 Assessment

SUMMARYSUMMARY

Section 1.1

Section 1.2

Section 1.3

Main Ideas■ Biology is the organized study of living things

and their interactions with their natural andphysical environments.

■ All living things have four characteristics incommon: organization, reproduction, growthand development, and the ability to adjust to theenvironment.

Vocabularyadaptation (p. 9)biology (p.3)development (p.8)energy (p.9)environment (p.8)evolution (p.10)growth (p.8)homeostasis (p.9)organism (p.6)organization (p.7)reproduction (p.7)response (p.9)species (p.7)stimulus (p.9)

Main Ideas■ Biologists use controlled experiments to obtain

data that either do or do not support a hypothe-sis. By publishing the results and conclusions of

an experiment, a scientist allows othersto try to verify the results. Repeatedverification over time leads to thedevelopment of a theory.

Vocabularycontrol (p.13)data (p.15)dependent variable

(p.13)experiment (p.12)hypothesis (p.12)independent variable

(p.13)safety symbol (p.14)scientific methods (p.11)theory (p.20)

Main Ideas■ Biologists do their work in laboratories and in

the field. They collect both quantitative anddescriptive data from their experiments andinvestigations.

■ Scientists conduct investigations to increaseknowledge about the natural world. Scientificresults may help solve some problems, but not all.

Vocabularyethics (p.24)technology (p.25)

CHAPTER 1 ASSESSMENT 29

1. For experiments to be considered valid, theresults must be ________.a. verified c. publishedb. inductive d. repeatable

UNDERSTANDING MAIN IDEASUNDERSTANDING MAIN IDEAS 2. Reproduction is an important life character-istic because all living things ________.a. replace themselvesb. show structurec. growd. adjust to surroundings

What IsBiology?

The Methodsof Biology

The Nature ofBiology

Main IdeasSummary statements can be used bystudents to review the major con-cepts of the chapter.

Using the VocabularyTo reinforce chapter vocabulary, usethe Content Mastery Booklet andthe activities in the Interactive Tutorfor Biology: The Dynamics of Life onthe Glencoe Science Web Site.www.glencoe.com/sec/science

1. d2. a

UNDERSTANDING MAIN IDEASUNDERSTANDING MAIN IDEAS


All ChapterAssessment

questions and answers have beenvalidated for accuracy and suitabil-ity by The Princeton Review.

Resource ManagerResource ManagerChapter Assessment, pp. 1-6MindJogger VideoquizzesComputer Test Bank BDOL Interactive CD-ROM,

Chapter 1 quiz

The term “organic” usually refers to foodsthat are produced without the use of chemi-

cal pesticides, herbicides, or fertilizers. Organicfarmers use nonchemical methods to controlpests and encourage crop growth. Beneficialinsects, such as ladybugs and trichogrammawasps, are brought in to feed on aphids, caterpil-lars, and other damaging insects. Instead ofapplying herbicides, organic farmers pull weedsby hand or by machine. In place of fertilizers,they use composting and crop rotation to enrichthe soil. Organic farming is very labor intensive,so organic foods are usually more expensive thanthose produced by conventional methods.

Different ViewpointsPeople usually buy organic products because

they want to be sure they’re getting nutritiousfood with no chemical residues. But there aredifferences of opinion about how much betterorganic food actually is, and even which foodsshould be called organic.


Organic Food: Is it healthier?The produce section of the supermarket has two bins of leafy lettuce thatlook very much alike. One is labeled “organic” and has a higher price.More and more consumers are willing to pay extra for organically grownfruits, vegetables, meats, and dairy products. What are they paying thatextra money for?

Comparing and Contrasting Propose yourown set of standards for defining organic fruitsand vegetables. Organize a debate in which youand your classmates present arguments to sup-port your proposed standards.

To find out more about theorganic food debate, visit the

Glencoe Science Web Site.www.glencoe.com/sec/science

INVESTIGATING THE ISSUEINVESTIGATING THE ISSUE

Is organic food healthier? Agricultural chemicals can leave residues on food and conta-minate drinking water supplies. Since exposureto some chemicals is known to cause healthproblems, including cancer, many consumersthink that organic foods are healthier. Chemicalpest controls kill beneficial organisms as well asunwanted pests, and can adversely affect thehealth of other animals, especially those that feedon insects. Organic pest control methods usuallytarget specific pests and have little effect on beneficial organisms.

Is conventionally grown food healthier?Chemical fertilizers and pesticides make it possible to grow larger crops at lower cost, which makes more food available to more people. Making sure everyone can afford an adequate supply of fruits and vegetables may be more important than the risk of disease posedby agricultural chemicals.

Not everyone agrees about what is organicand what isn’t. Should genetically engineeredplant or animal foods be considered organic?What about herbs or meats preserved by irradiation, or lettuce and tomatoes fertilizedwith sewage sludge?

Produce from anorganic farm

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PurposeThis feature allows students toanalyze claims made aboutorganically grown produce.Students are encouraged to for-mulate and present their ownviews.

Teaching Strategies■ Provide recent newspaper andmagazine articles regardingclaims about organically grownproduce.■ Ask students to discuss theadvantages and disadvantages ofusing herbicides, pesticides, andfertilizers on crops.■ Have students interview pro-duce managers in several super-markets to obtain their viewsconcerning organically grownproduce.■ Have students investigate themethods used for displaying pro-duce in supermarkets. Ask themto write a summary of their find-ings.

Investigating the IssueStudent standards will differ, andthis produces fuel for the debate.Standards might include theexclusion of all agriculturalchemicals, or the reduction ofchemicals.

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Going FurtherGoing Further

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VIDEOTAPEMindJogger Videoquizzes

Chapter 1: Biology: The Study of LifeHave students work in groups as they playthe videoquiz game to review key chapterconcepts.




CHAPTER 1 ASSESSMENT 31

19. The idea that germs are the cause of diseasehas been continuously supported by experi-ments and has, therefore, been elevated tothe status of a ________.

20. The standard group against which others aremeasured in an experiment is a ________.

21. Describe how the human body shows the lifecharacteristic of organization.

22. Explain the relationships among an organism’senvironment, adaptations, and evolution.

23. Comparing and Contrasting Consider thefollowing items: a flame, bubbles blown froma bubble wand, and a balloon released intothe air. List characteristics of each that mightindicate life and those that indicate they arenot alive.

24. Concept Mapping Complete the conceptmap by using the following vocabulary terms:experiment, theory, hypothesis, scientificmethods

THINKING CRITICALLYTHINKING CRITICALLY

APPLYING MAIN IDEASAPPLYING MAIN IDEAS

ASSESSING KNOWLEDGE & SKILLSASSESSING KNOWLEDGE & SKILLS

A team of students measured the number ofseeds that germinated over ten days in acontrol group at 18°c and in an experimen-tal group at 25°c. They graphed their dataas shown below.

Interpreting Data Study the graph andanswer the following questions.1. Which of the following would represent

the hypothesis tested?a. Black seeds are best.b. Seeds germinate faster at warmer

temperatures.c. Fertilization of seeds requires heat.d. Seeds germinate when freezing.

2. When was the first appropriate day toend the experiment?a. day 3 c. day 7b. day 6 d. day 9

3. Which of the following was the inde-pendent variable?a. kind of seeds c. temperatureb. number germinating d. time

4. Which of the following was the depen-dent variable?a. kind of seeds c. temperatureb. number germinating d. time

5. Interpreting Data Describe the germi-nation rate between days 3 and 5 in thecontrol group.

For additional review, use the assessmentoptions for this chapter found on the Biology: TheDynamics of Life Interactive CD-ROM and on theGlencoe Science Web Site.www.glencoe.com/sec/science

CD-ROM

Seed

s ger

min

ated

Day

The Effect of Fertilizer on Germination

50403020100

1 2 3 4 5 6 7 8 9 10

Experimental group

Control group

may begin with an observation,which leads to a(n)

1.

that is tested by a(n)

2.

and, after many repetitions, may result in a(n)

3.

4.

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21. It is composed of cells, whichare organized into tissues andorgans, which are organizedinto body systems.

22. Evolution is the result of organ-isms adapting to environmentalchanges.

23. A flame has energy and mayappear to grow and reproduce.Bubbles blown from a wandmove and may grow. A balloonreleased into air moves. Theseobjects cannot adapt tochanges in the environment ormaintain homeostasis.

24. 1. Scientific methods; 2. Hypo-thesis; 3. Experiment; 4. Theory

THINKING CRITICALLYTHINKING CRITICALLY

APPLYING MAIN IDEASAPPLYING MAIN IDEAS


1. b2. d3. c4. b5. Between days 3 and 5,

approximately 5 seedsgerminated per day.


3. The photograph to the right is an example of which characteristic of life?a. evolutionb. reproductionc. developmentd. response to a

stimulus4. Which of the following is an appropriate sci-

entific question?a. How do paramecia behave when a pond

begins to dry up?b. Which perfume smells the best?c. Which religion is most sound?d. Are llamas less valuable than camels?

5. If data from repeated experiments do notsupport the hypothesis, what is the scientist’snext step?a. Give up.b. Revise the hypothesis.c. Repeat the experiment.d. Overturn the theory.

6. Similar-looking organisms, such as the dogsshown below, that can interbreed and pro-duce fertile offspring are called ________.a. a living system c. organizationb. an adaptation d. a species

7. The environment includes ________.a. air, water, weatherb. response to a stimulusc. adaptationsd. evolution

8. Which of the following terms are mostrelated to each other?a. adaptation—responseb. stimulus—growthc. adaptation—evolutiond. stimulus—evolution

9. Which of the following is not an appropriatequestion for science to consider?a. How many seals can a killer whale con-

sume in a day?b. Which type of orchid flower is most beau-

tiful?c. What birds prefer seeds as a food source?d. When do hoofed mammals in Africa

migrate northward?10. The single factor that is altered in an experi-

ment is the ________.a. controlb. dependent variablec. hypothesisd. independent variable

11. The information gained from an experimentis called ________.

12. The application of scientific research to soci-ety’s needs is ________.

13. A procedure that tests a hypothesis is a(n)________.

14. Processes that scientists use to solve a prob-lem are called ________.

15. An explanation of a natural phenomenonwith a high degree of confidence is a(n)________.

16. The group that is not altered in an experi-ment is the ________.

17. The single change in the manipulated groupin an experiment is a(n) ________ variable.

18. When a horse swats a fly with its tail, the flyis a ________ and the swat of the tail is a________.

30 CHAPTER 1 ASSESSMENT

TEST–TAKING TIPTEST–TAKING TIP

Words Are Easy to Learn Make a huge stack of vocabulary flashcards andstudy them. Use your new words in daily conversa-tion. The great thing about learning new words isthe ability to express yourself more specifically.

30

3. c4. a5. b6. d7. a8. c9. b

10. d11. data12. technology13. experiment14. scientific methods15. theory16. control17. independent18. stimulus; response19. theory20. control



Growth and DevelopmentWhen living things grow, their cells enlarge

and divide. As organisms age, other changes alsotake place. Development consists of the changesin an organism that take place over time.

ReproductionLiving things reproduce by transmitting their

hereditary information from one generation tothe next.

Scientific MethodsScientists employ a variety of scientific meth-

ods to answer questions and solve problems. Notall investigations will use all methods, and theorder in which they are used will vary.

ObservationCuriosity leads scientists to make observations

that raise questions about natural phenomena.

HypothesisA statement that can be tested and presents

a possible solution to a question is a hypothesis.

ExperimentAfter making a

hypothesis, the next stepis to test it. An experi-ment is a formal methodof testing a hypothesis. Ina controlled experiment,two groups are testedand all conditions exceptone are kept the same forboth groups. The singlecondition that changes isthe independent variable.A condition caused by thechange in the indepen-dent variable is a depen-dent variable.

TheoryWhen a hypothesis

has been confirmed bymany experiments, it may become a theory.Theories explain naturalphenomena.

What Is Biology?

33

BIODIGESTBIODIGEST

Many experiments are con-ducted in the laboratory,where conditions can beeasily controlled.

BIODIGEST ASSESSMENTBIODIGEST ASSESSMENT

Understanding Main Ideas1. The basic unit of organization of living

things is ________.a. an atom c. a cellb. an organism d. an organ

2. Storing energy obtained from food is anexample of ________.a. evolution c. responseb. homeostasis d. growth

3. A hypothesis that is supported many timesbecomes ________.a. an experiment c. a theoryb. a conclusion d. an observation

4. All of the procedures scientists use toanswer questions are ________.a. life characteristics c. researchb. scientific methods d. hypotheses

5. To test a hypothesis, a scientist may________.a. do an experimentb. write a theoryc. do research in a libraryd. make some observations

Thinking Critically1. List the characteristics you would check

to see if a pine tree is a living thing. Givean example that shows how the treeexhibits each characteristic.

2. Compare the characteristics of life with theflames of a fire. How are they similar anddifferent?

3. Why do most experiments have a control?Describe an experiment that does not havea control.

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BIODIGESTBIODIGEST

BIODIGEST ASSESSMENTBIODIGEST ASSESSMENT

Understanding Main Ideas1. c2. b3. c4. b5. a

Thinking Critically1. Cells would show cellular structure;

homeostasis is shown by making and usingenergy from sunlight; growing toward thelight is a response to stimulus; growth anddevelopment would be shown in thechanges since the plant was a seed; repro-duction occurs when it produces new seeds.

2. Fires can grow, use energy, and reproduce.Fires are not composed of cells.

3. A control is a basis for comparison. A behav-ior experiment may not have a control.

Characteristics of LifeBiologists have formulated a list of character-

istics by which we can recognize living things.

OrganizationAll living things are organized into cells.

Organisms may be composed of one cell or manycells. Cells are like rooms in a building. You canthink of a many-celled organism as a building con-taining many rooms. Groups of rooms in differentareas of the building are used for different pur-poses. These areas are analogous to the tissues,organs, and body systems of plants and animals.

FOCUS ON CAREERSFOCUS ON CAREERS

Thousands of career opportunitiesare available in the biological

sciences. Some of these careers requireonly a high school education. Othersrequire a college degree, or even anadvanced degree. Many careers in biology involve work as a research biologist in the field or in a laboratorysetting.

Other careers also rely on skills orknowledge about biology. Doctors anddentists, nurses and laboratory techni-cians, florists, foresters, and zookeepersall must have a knowledge of biology.Careers related to the biological sci-ences also include food processing,farming, and ranching. Can you thinkof some other careers in which biologyplays an important role?

Biology at Work

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What Is Biology?Living things abound almost everywhere

on Earth—in deep ocean trenches, atop thehighest mountains, in dry deserts, and in wet tropicalforests. Biology is the study of living organisms and the interac-tions among them. Biologists use a variety of scientific methodsto study the details of life.

For a preview of the what is biology unit, study this BioDigest before you read the chapter.After you have studied the chapter, you can use the BioDigest to review the unit.

BIODIGESTBIODIGEST

If you enjoy work-ing outdoors, acareer in field biol-ogy may be for you.

HomeostasisA stable internal environment is necessary for

life. Organisms maintain this stability throughhomeostasis, which is a process that requires thecontrolled use of energy in cells. Plants obtainenergy by converting light, water, and carbondioxide into food. Other organisms obtain theirenergy indirectly from plants.

Response to a StimulusLiving things respond to changes in their

external environment. Any change, such as a risein temperature or the presence of food, is a stim-ulus.

All livingthings share

certain characteristics.What characteristicstell you these robinsare living organisms?

32

BIODIGESTBIODIGEST

MultipleLearningStyles

Look for the following logosfor strategies that emphasizedifferent learning modalities.

Visual-SpatialQuick Demo, p. 32;

Microscope Activity, p. 33;Reteach, p. 33; Extension,p. 33

Microscope ActivityVisual-Spatial Have studentsexamine slides of protists.

Ask what characteristics of lifethe organisms share.

3 AssessCheck for UnderstandingHave students explain why sci-ence and technology cannotanswer all questions.

ReteachVisual-Spatial Ask studentsto observe a seed and make

a hypothesis about whether it isalive. Have them plant the seedand record the characteristics oflife they note over the period of aweek or two.

ExtensionVisual-Spatial Have studentsmake a bulletin board col-

lage of pictures of living organ-isms.

Skill Provide students withexamples of living organisms andnonliving objects. Ask them togroup the living organismstogether and the nonlivingobjects together. Include someonce-living objects to make athird group.

4 CloseDiscussionAsk students to discuss specificexamples of a stimulus and theresulting response they may haveobserved in common animals.Have students identify both thestimulus and response, and spec-ulate about how the responsemight help the organism main-tain homeostasis.

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Visual-Spatial Display asmall animal such as an

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National Science Education StandardsUCP,.1, A.2, G.1, G.2

PreparePurposeThis BioDigest can be used as abrief overview of the nature ofscience and the characteristics oflife. If time is limited, you maywish to use this unit summary toteach these concepts in place ofChapter 1.

Key ConceptsStudents are introduced to thecharacteristics of life and themethods of science. They learnabout the nature and limitationsof science and technology.

1 FocusBellringer Show students a candle flame anda caged mouse. Ask students toexplain the similarities and differ-ences of the two to elicit thecharacteristics of living things.

2 Teach

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