READING STRATEGY

1 Sorting It All OutImagine that you live in a tropical rain forest and must get your own food, shelter, and clothing from the forest. What do you need to know to survive in the forest?

To survive in the rain forest, you need to know which plants are safe to eat and which are not. You need to know which animals you can eat and which might eat you. In other words, you need to study the living things around you and organize them into categories, or classify them. ClassificationClassification is putting things into orderly groups based on similar characteristics.

Why Classify?For thousands of years, humans have classified living things based on usefulness. The Chácabo people of Bolivia know of 360 types of plants that grow in the forest where they live. Of these 360 plant types, 305 are useful to the Chácabo.

Some biologists, such as those shown in Figure 1, classify living and extinct organisms. Scientists classify organisms to help make sense and order of the many kinds of living things in the world. Biologists use a system to classify living things. This system groups organisms according to the characteristics they share. The classification of living things makes it easier for biologists to answer many important questions, such as the following:

• How many known species are there?

• What are the defining characteristics of each species?

• What are the relationships between these species?

✓✓Reading Check What are three questions that classifying organ-isms can help answer? (See the Appendix for answers to Reading Checks.)

classificationclassification the division of organisms into groups, or classes, based on specific characteristics

Figure 1 These biologists are sorting rain-forest plant material.

What You Will Learn

Explain why and how organisms are classified.List the eight levels of classification.Explain scientific names.Describe how dichotomous keys help in identifying organisms.

Vocabularyclassificationtaxonomydichotomous key

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

Chapter 7 164

Platypus Brown Bear Lion House Cat

Retractableclaws

Giving birth to live young

Hair, mammary glands

Abilityto purr

Section 1 Sorting It All Out

How Do Scientists Classify Organisms?Before the 1600s, many scientists divided organisms intotwo groups: plants and animals. But as more organisms werediscovered, some did not fit into either group. In the 1700s,Carolus Linnaeus (KAR uh luhs li NAY uhs), a Swedish scientist,founded modern taxonomy. TaxonomyTaxonomy (taks AHN uh mee) isthe science of describing, classifying, and naming living things.Linnaeus tried to classify all living things based on their shapeand structure. Today, scientists use a system of classificationthat is very similar to the one that Linnaeus developed.

Classification TodayTaxonomists use an eight-level system to classify living thingsbased on shared characteristics. Scientists also use shared char-acteristics to hypothesize how closely related living things are.The more characteristics the organisms share, the more closelyrelated the organisms may be. For example, the platypus, brownbear, lion, and house cat are thought to be related becausethey share many characteristics. These animals have hair andmammary glands, so they are grouped together as mammals.But they can be further classified into more-specific groups.

Branching DiagramsLook at the branching diagram in Figure 2. Several character-istics are listed along the line that points to the right. Eachcharacteristic is shared by the animals to the right of it. All ofthe animals shown have hair and mammary glands. But onlythe bear, lion, and house cat give birth to live young. Thelion and the house cat have retractable claws, but the otheranimals do not. Thus, the lion and the house cat are moreclosely related to each other than to the other animals.

Figure 2 This branchingdiagram shows the similaritiesand differences between fourmammals.

taxonomytaxonomy the science ofdescribing, naming, and classifyingorganisms

A Branching Diagram1. Construct a diagram simi-

lar to the one in Figure 2.2. Use a frog, a snake, a kan-

garoo, and a rabbit in yourdiagram.

3. Think of one major changethat happened before thefrog evolved.

4. For the last three organ-isms, think of a changethat happened betweenone of these organismsand the other two. Writeall of these changes inyour diagram.

165

Levels of ClassificationEvery living thing is classified into one of three domains.Domains are the largest and most general groups. All livingthings in a domain are sorted into kingdoms. The members ofone kingdom are more like each other than they are like themembers of another kingdom. All living things in a kingdomare further sorted into phyla (singular, phylum). The membersof a phylum are sorted into classes. Each class includes oneor more orders. Orders are separated into families. Familiesare broken into genera (singular, genus). And genera are sortedinto species. A species is a group of organisms that are closelyrelated and can mate to produce fertile offspring. Figure 3 showsthe classification of a house cat from the kingdom Animaliato the species Felis domesticus.

Scientific NamesBy classifying organisms, biologists can give organisms scientificnames. A scientific name remains the same for a specific kindof organism even if the organism has many common names.Before Linnaeus’s time, scholars used names that were as longas 12 words to identify species. This system was hard to workwith because the names were so long. The system was alsohard to use because individual scientists named organisms dif-ferently. So, an organism could have more than one name.

Kingdom Animalia

All animals are in thekingdom Animalia.

Phylum Chordata

All animals in thephylum Chordata havea hollow nerve cord.Most have a backbone.

Class Mammalia

Animals in the classMammalia have abackbone. They alsonurse their young.

Order Carnivora

Animals in the orderCarnivora have a back-bone and nurse theiryoung. They also havespecial teeth for tearingmeat.

For another activity relatedto this chapter, go togo.hrw.com and type in thekeyword HL5CLSW.

Figure 3 The eight levelsof classification are domain,kingdom, phylum, class, order,family, genus, and species.

166 Chapter 7 Classification

Section 1 Sorting It All Out

Two-Part NamesLinnaeus simplified the naming of living things by giving eachspecies a two-part scientific name. For example, the scientificname for the Asian elephant is Elephas maximus (EL uh fuhsMAK suh muhs). The first part of the name, Elephas, is thegenus name. The second part, maximus, is the specific name.No other species has the name Elephas maximus. Naming ruleshelp scientists communicate clearly about living things.

All genus names begin with a capital letter. All specificnames begin with a lowercase letter. Usually, both words areunderlined or italicized. But if the surrounding text is italicized,the scientific name is not, as Figure 4 shows. These printingstyles show a reader which words are the scientific name.

Scientific names, which are usually in Latin or Greek,contain information about an organism. The name of theanimal shown in Figure 4 is Tyrannosaurus rex. Tyrannosau-rus is a combination of two Greek words and means “tyrantlizard.” The word rex is Latin for “king.” The name tells youthat this animal was probably not a passive grass eater! Some-times, Tyrannosaurus rex is referred to as T. rex. To be correct,the scientific name must consist of the genus name (or itsabbreviation) and the specific name.

✓✓Reading Check What are the two parts of a scientific name?

Figure 4 You wouldnever call Tyrannosaurusrex just rex!

Family Felidae

Animals in the familyFelidae are cats. Theyhave a backbone, nursetheir young, have specialteeth for tearing meat,and have retractableclaws.

Genus Felis

Animals in the genusFelis have traits of otheranimals in the samefamily. However, thesecats cannot roar; they canonly purr.

Species Felis domesticus

The species Felisdomesticus is the com-mon house cat. Thehouse cat shares traitswith all of the organismsin the levels above thespecies level, but it alsohas unique traits.

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Dichotomous KeysYou might someday turn over a rock and find an organ-ism that you don’t recognize. How would you identify the organism? Taxonomists have developed special guides to help scientists identify organisms. A dichotomous keydichotomous key(die KAHT uh muhs KEE) is an identification aid that uses sequential pairs of descriptive statements. There are only two alternative responses for each statement. From each pair of statements, the person trying to identify the organism chooses the statement that describes the organism. Either the chosen statement identifies the organism or the person is directed to another pair of statements. By working through the statements in the key in order, the person can eventually identify the organism. Using the simple dichotomous key in Figure 5, try to identify the two animals shown.

✓✓Reading Check What is a dichotomous key?

dichotomous keydichotomous key an aid that is used to identify organisms and that consists of the answers to a series of questions

1. a. This mammal flies. Its “hand” forms a wing. little brown batb. This mammal does not fly. It’s “hand” does not form a wing. Go to step 2.

2. a. This mammal has no hair on its tail. Go to step 3.b. This mammal has hair on its tail. Go to step 4.

3. a. This mammal has a short, naked tail. eastern moleb. This mammal has a long, naked tail. Go to step 5.

4. a. This mammal has a black mask across its face. raccoonb. This mammal does not have a black mask across its face. Go to step 6.

5. a. This mammal has a tail that is flat and paddle shaped. beaverb. This mammal has a tail that is not flat or paddle shaped. opossum

6. a. This mammal is brown and has a white underbelly. Go to step 7.b. This mammal is not brown and does not have a white underbelly. Go to step 8.

7. a. This mammal has a long, furry tail that is black on the tip. longtail weaselb. This mammal has a long tail that has little fur. white-footed mouse

8. a. This mammal is black and has a narrow white stripe on its forehead and broad white stripes on its back. striped skunk

b. This mammal is not black and does not have white stripes. Go to step 9.

9. a. This mammal has long ears and a short, cottony tail. eastern cottontailb. This mammal has short ears and a medium-length tail. woodchuck

Figure 5 A dichotomous key can help you identify organisms.

168 Chapter 7 Classification

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SummarySummary

Review

A Growing SystemYou may think that all of the organisms on Earth have alreadybeen classified. But people are still discovering and classifyingorganisms. Some newly discovered organisms fit into existingcategories. But sometimes, someone discovers new evidence oran organism that is so different from other organisms that itdoes not fit existing categories. For example, in 1995, scientistsstudied an organism named Symbion pandora (SIM bee AHN panDAWR uh). Scientists found S. pandora living on lobster lips!Scientists learned that S. pandora had some characteristics thatno other known organism had. In fact, scientists trying to clas-sify S. pandora found that it didn’t fit in any existing phylum.So, taxonomists created a new phylum for S. pandora.

•• In classification, organ-isms are groupedaccording to the charac-teristics the organismsshare. Classification letsscientists answer impor-tant questions about therelationships betweenorganisms.

•• The eight levels ofclassification are domain,kingdom, phylum, class,order, family, genus, andspecies.

•• An organism has onetwo-part scientific name.

•• A dichotomous key isa tool for identifyingorganisms that uses aseries of paired descrip-tive statements.

Using Key Terms

1. In your own words, write adefinition for each of the fol-lowing terms: classification andtaxonomy.

Understanding Key Ideas

2. The two parts of a scientificname are the names of thegenus and the

a. specific name.b. phylum name.c. family name.d. order name.

3. Why do scientists use scientificnames for organisms?

4. List the eight levels ofclassification.

5. Describe how a dichotomouskey helps scientists identifyorganisms.

Critical Thinking

6. Analyzing Processes Biologiststhink that millions of species arenot classified yet. Why do youthink so many species have notbeen classified yet?

7. Applying Concepts Both dol-phins and sharks have a tail andfins. How can you determine ifdolphins and sharks are closelyrelated?

Interpreting Graphics

Use the figure below to answer thequestions that follow.

8. Which plant is most similar tothe hibiscus?

9. Which plant is least similar to thehibiscus?

Topic: Basis for Classification; Levels ofClassification

SciLinks code: HSM0138; HSM0870

Pine tree HibiscusMoss Fern

Ability to live on land

Tissues that transportmaterials

Seeds

Flowers

169

READING STRATEGY

2 Domains and KingdomsWhat do you call an organism that is green, makes its own food, lives in pond water, and moves? Is it a plant, an animal, or something in between?

For hundreds of years, all living things were classified as either plants or animals. But over time, scientists discovered species that did not fit easily into these two kingdoms. For example, an organism of the genus Euglena, such as the one shown in Figure 1, has characteristics of both plants and animals. How would you classify such an organism?

What Is It?Organisms are classified by their characteristics. For example, euglenoids, which include members of the genus Euglena, have the following characteristics:

• Euglenoids are single celled and live in pond water.

• Euglenoids are green and make their own food by photosynthesis.

These characteristics might lead you to conclude that eugle-noids are plants. However, you should consider the following characteristics of euglenoids:

• Euglenoids move by whipping their “tails,” which are called flagella.

• Euglenoids can feed on other organisms.

Plants do not move around and usually do not eat other organisms. So, are euglenoids animals? As you can see, eugle-noids do not fit into plant or animal categories. Scientists solved this classification problem by adding another kingdom—kingdom Protista—to classify organisms such as euglenoids.

As scientists learned more about living things, they changed the classification system. Today, there are three domains in the classification system. Domains represent the largest dif-ferences between organisms. These domains are divided into several kingdoms.

Figure 1 How would you classify this organism? This member of the genus Euglena, which is shown here highly magnified, has characteristics of both plants and animals.

What You Will Learn

Explain how classification developed as greater numbers of organisms became known.Describe the three domains.Describe four kingdoms in the domain Eukarya.

VocabularyArchaea FungiBacteria PlantaeEukarya AnimaliaProtista

Discussion Read this section silently. Write down questions that you have about this section. Discuss your ques-tions in a small group.

170 Chapter 7 Classification

The Domain ArchaeaThe domain ArchaeaArchaea (ahr KEE uh) is made up entirely of archaea. Archaea are one of two kinds of prokaryotes (proh KAR ee OHTS). Prokaryotes are single-celled organisms that do not have a nucleus. Archaea were first discovered living in extreme environments, where other organisms could not sur-vive. Figure 2 shows a hot spring in Yellowstone National Park. The yellow and orange rings around the edge of the hot spring are made up of billions of archaea. Some archaea can also be found in moderate environments, such as the open ocean.

✓✓Reading Check Describe one characteristic of an organism in

the domain Archaea.

The Domain BacteriaAll bacteria (bak TEER ee uh) belong to the domain Bacteria.Bacteria.Bacteria are another kind of prokaryote. Bacteria can be found in soil, water, and even on and inside the human body! For example, Escherichia coli (ESH uh RIK ee uh KOH LIE), shown in Figure 3, is present in large numbers in human intestines, where it produces vitamin K. One kind of bacterium converts milk into yogurt. Some bacteria cause diseases, such as pneu-monia. Other bacteria make chemicals that help humans fight disease-causing bacteria.

Figure 3 Specimens of E. coli are shown on the point of a pin under a scanning electron microscope. These bacteria live in the intestines of animals and decompose undigested food.

Figure 2 The Grand Prismatic Spring in Yellowstone National Park contains water that is about 90°C (194°F). The spring is home to archaea that thrive in its hot water.

ArchaeaArchaea in a modern taxonomic system, a domain made up of pro-karyotes (most of which are known to live in extreme environments) that are distinguished from other prokary-otes by differences in their genetics and in the makeup of their cell wall; this domain aligns with the tradi-tional kingdom Archaebacteria

BacteriaBacteria in a modern taxonomic system, a domain made up of pro-karyotes that usually have a cell wall and that usually reproduce by cell division; this domain aligns with the traditional kingdom Eubacteria

171

The Domain EukaryaAll organisms whose cells have a nucleus and

membrane-bound organelles are called eukaryotes. Eukaryotes belong to the domain Eukarya.Eukarya. Four kingdoms currently make up the domain Eukarya: Protista, Fungi, Plantae, and Animalia.

The Kingdom ProtistaToday, members of the kingdom ProtistaProtista (proh TIST uh), commonly called protists, are single-celled or simple multicellular organisms. Scientists think that the first protists evolved from ancient bacteria about 2 billion years ago. Eventually, ancient protists gave rise to fungi, plants, and animals. The kingdom Protista contains many kinds of organisms. Some animal-like protists are called protozoans. Some plantlike protists are called algae. Protists also include slime molds, such as the one shown in Figure 4, and euglenoids.

The Kingdom FungiMolds and mushrooms are examples of the complex, mul-ticellular members of the kingdom FungiFungi (FUHN JIE). Unlike plants, fungi do not perform photosynthesis. Unlike animals, fungi do not eat food. Instead, fungi absorb nutrients from substances in their surroundings. They use digestive juices to break down the substances. Figure 5 shows a very poisonous fungus. Never eat wild fungi.

EukaryaEukarya in a modern taxonomic system, a domain made up of all eukaryotes; this domain aligns with the traditional kingdoms Protista, Fungi, Plantae, and Animalia

Figure 5 This beautiful fungus of the genus Amanita is poisonous.

Figure 4 This slime mold is a protist.

Chapter 7 172

Section 2 Domains and Kingdoms

The Kingdom PlantaeAlthough plants vary remarkably in size and form, mostpeople easily recognize the members of the kingdom Plantae.PlantaePlantae consists of organisms that are eukaryotic, have cell walls,and make food through photosynthesis. For photosynthesis tooccur, plants must be exposed to sunlight. Plants can thereforebe found on land and in water that light can penetrate.

The food that plants make is important not only for theplants but also for all of the organisms that get nutrients fromplants. Most life on Earth is dependent on plants. For example,some fungi, protists, and bacteria consume plants. When theseorganisms digest the plant ma terial, they get energy and nutri-ents made by the plants.

Plants also provide habitat for other organisms. The giantsequoias in Figure 6 and the flowering plants in Figure 7 providebirds, insects, and other animals with a place to live.

✓✓Reading Check How do plants provide energy and nutrients toother organisms?

PlantaePlantae a kingdom made up ofcomplex, multicellular organisms thatare usually green, have cell wallsmade of cellulose, cannot movearound, and use the sun’s energy tomake sugar by photosynthesis

Figure 6 Giant sequoias canmeasure 30 m around at thebase and can grow to more than91.5 m tall.

Ring-Around-the-SequoiaHow many students wouldhave to join hands to form ahuman chain around a giantsequoia that is 30 m in cir-cumference? Assume for thiscalculation that the averagestudent can extend his or herarms about 1.3 m.

Figure 7 Plants such as theseare common in the Tropics.

173

The Kingdom AnimaliaThe kingdom AnimaliaAnimalia contains complex, multicellular organ-isms that don’t have cell walls, are usually able to move around,and have specialized sense organs. These sense organs helpmost animals quickly respond to their environment. Organismsin the kingdom Animalia are commonly called animals. Youprobably recognize many of the organisms in the kingdomAnimalia. All of the organisms in Figure 8 are animals.

Animals depend on the organisms from other kingdoms.For example, animals depend on plants for food. Animals alsodepend on bacteria and fungi to recycle the nutrients foundin dead organisms.

AnimaliaAnimalia a kingdom made up ofcomplex, multicellular organismsthat lack cell walls, can usually movearound, and quickly respond to theirenvironment

WRITINGSKILL

Animals That Help Humans have depended onanimals for thousands of years. Many people around

the world still use oxen to farm. Camels, horses, donkeys, goats,and llamas are all still used as pack animals. Dogs still help herdsheep, protect property, and help people hunt. Scientists are evendiscovering new ways that animals can help us. For example, sci-entists are training bees to help find buried land mines. Using thelibrary or the Internet, research an animal that helps people. Makea poster describing the animal and the animal’s scientific name.The poster should show who uses the animal, how the animal isused, and how long people have depended on the animal. Find ordraw pictures to put on your poster.

Figure 8 The kingdom Animaliacontains many differentorganisms, such as eagles,tortoises, and beetles.

174 Chapter 7 Classification

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SummarySummary

Review

Strange OrganismsClassifying organisms is often not easy. Like animals, someplants can eat other organisms to obtain nutrients. Some pro-tists can use photosynthesis as plants do and can move aroundas animals do. The kingdom Animalia also includes membersthat might surprise you, such as worms, insects, and corals.

The red cup sponge in Figure 9 is also an animal. Spongesare usually considered the simplest animals. They lack senseorgans, and most of them cannot move. Scientists used toclassify sponges as plants. But sponges cannot make their ownfood. They must eat other organisms to get nutrients, whichis one reason that sponges are classified as animals.

✓✓Reading Check Why were sponges once thought to be plants?Figure 9 This red cup sponge isa simple animal.

•• In the past, organismswere classified as plantsor animals. As scientistsdiscovered more species,they found that organ-isms did not alwaysfit into one of thesetwo categories, so theychanged the classifica-tion system.

•• Today, domains are thelargest groups of relatedorganisms. The threedomains are Archaeaand Bacteria, both ofwhich consist of prokary-otes, and Eukarya, whichconsists of eukaryotes.

•• The kingdoms of thedomain Eukarya are Pro-tista, Fungi, Plantae, andAnimalia.

Using Key Terms

For each pair of terms, explain howthe meanings of the terms differ.

1. Archaea and Bacteria

2. Plantae and Fungi

Understanding Key Ideas

3. Biological classification schemeschange

a. as new evidence and morekinds of organisms arediscovered.

b. every 100 years.c. when scientists disagree.d. only once.

4. Describe the characteristics ofeach of the three domains.

5. Describe the four kingdoms ofdomain Eukarya.

Math Skills

6. A certain bacterium can divideevery 30 min. If you begin with1 bacterium, when will you havemore than 1,000 bacteria?

Critical Thinking

7. Identifying RelationshipsHow are bacteria similar tofungi? How are fungi similar toanimals?

8. Analyzing Methods Why doyou think Linnaeus did notinclude classification kingdomsfor categories of archaea andbacteria?

9. Applying Concepts The Venus’flytrap does not move around. Itcan make its own food by usingphotosynthesis. It can also trapinsects and digest the insects toget nutrients. The flytrap alsohas a cell wall. Into which king-dom would you place the Venus’flytrap? What makes this organ-ism unusual in the kingdom youchose?

Topic: KingdomsSciLinks code: HSM1397

175

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

Animalia ProtistaBacteria PlantaeArchaea classificationtaxonomy

1 Linnaeus founded the science of .

2 Prokaryotes that live in extremeenvironments are in the domain .

3 Complex multicellular organismsthat can usually move around andrespond to their environment are inthe kingdom .

4 A system of can help group ani-mals into categories.

5 Prokaryotes that can cause diseases arein the domain .

Multiple Choice

6 Scientists classify organisms by

a. arranging the organisms in orderlygroups.

b. giving the organisms many commonnames.

c. deciding whether the organisms areuseful.

d. using only existing categories ofclassifi cation.

7 When the eight levels of classifi cationare listed from broadest to narrowest,which level is sixth in the list?

a. classb. orderc. genusd. family

8 The scientifi c name for the Europeanwhite waterlily is Nymphaea alba. Towhich genus does this plant belong?

a. Nymphaea c. water lilyb. alba d. alba lily

9Animalia, Protista, Fungi, and Plantaeare the

a. scientifi c names of differentorganisms.

b. names of kingdoms.c. levels of classifi cation.d. scientists who organized taxonomy.

0 The simple, single-celled organismsthat live in your intestines areclassifi ed in the domain

a. Protista. c. Archaea.b. Bacteria. d. Eukarya.

q What kind of organism thrives inhot springs and other extremeenvironments?

a. fungus c. archaeanb. bacterium d. protist

USING KEY TERMS

UNDERSTANDING KEY IDEAS

178 Chapter 7 Classification

Chapter Review

Short Answer

w Why is the use of scientifi c namesimportant in biology?

e What kind of evidence is used by mod-ern taxonomists to classify organismsbased on evolutionary relationships?

r Is a bacterium a type of eukaryote?Explain your answer

t Scientists used to classify organisms aseither plants or animals. Why doesn’tthat classifi cation system work?

yConcept Mapping Use the followingterms to create a concept map: king-dom, fern, lizard, Animalia, Fungi, algae,Protista, Plantae, and mushroom.

uAnalyzing Methods Explain how thelevels of classifi cation depend on thesimilarities and differences betweenorganisms.

iMaking Inferences Explain why twospecies that belong to the same genus,such as white oak (Quercus alba) andcork oak (Quercus suber), also belong tothe same family.

o Identifying Relationships What char-acteristics do the members of the fourkingdoms of the domain Eukarya havein common?

Use the branching diagram of selectedprimates below to answer the questionsthat follow.

p Which primate is the closest relative tothe common ancestor of all primates?

a Which primate shares the most traitswith humans?

s Do both lemurs and humans havethe characteristics listed at point D?Explain your answer.

d What characteristic do baboons havethat lemurs do not have? Explain youranswer.

CRITICAL THINKING

INTERPRETING GRAPHICS

Bipedal, language

Lemur HumanChimpanzeeBaboon

A

B

C

D

Muchlarger brain

Color vision

Binocular vision,opposable thumbs

179

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

Passage 1 When organizing life on Earth intocategories, we must remember that organisms arenot equally distributed throughout the categoriesof our classification system. We often think ofEarth’s living things as only the plants and animalsthat live on Earth’s surface. However, the largestdomains in terms of the number of individualsand total mass are the domains Archaea andBacteria. And a common home of archaea andbacteria may be deep within the Earth’s crust.

1. In the passage, what does distributed mean?

A dividedB importantC visibleD variable

2. According to the passage, what are most of theorganisms living on Earth?

F plantsG animalsH fungiI archaea and bacteria

3. Which of the following statements is a factaccording to the passage?

A All organisms are equally distributed overEarth’s surface.

B Plants are the most important organisms onEarth.

C Many archaea and bacteria may live deepwithin Earth’s crust.

D Archaea and bacteria are equally distributedover Earth’s surface.

Passage 2 When you think of an animal, whatdo you imagine? You may think of a dog, a cat, ora parrot. All of those organisms are animals. Butthe animal kingdom also includes some membersthat might surprise you, such as worms, insects,corals, and sponges.

1. In the passage, what is coral?

A a kind of animalB a kind of insectC a color similar to pinkD an organism found in lakes and streams

2. What can you infer from the passage?

F All members of the animal kingdom arevisible.

G Parrots make good pets.H Not all members of the animal kingdom

have DNA.I Members of the animal kingdom come in

many shapes and sizes.

3. Which of the following can you infer from thepassage?

A Worms and corals make good pets.B Corals and cats have some traits in

common.C All organisms are animals.D Worms, corals, insects, and sponges are in

the same family.

4. In the passage, what does members mean?

F teammatesG limbsH individuals admitted to a clubI components

180 Chapter 7 Classification

Stand

ardized

Test Prep

aration

Standardized Test Preparation

The Venn diagrams below show two classifica-tion systems. Use the diagrams to answer the questions that follow.

Read each question below, and choose the best answer.

1. Scientists estimate that millions of species have not yet been discovered and classifi ed. About 1.8 million species have been discovered and classifi ed. If scientists think that this 1.8 million makes up only 10% of the total number of species on Earth, how many species do scientists think exist on Earth?

A 180 million B 18 millionC 1.8 millionD 180,000

2. Sequoia trees can grow to more than 90 m in height. There are 3.28 feet in 1 meter. How many feet are in 90 m?

F 27.4 ftG 95.2 ftH 270 ftI 295.2 ft

1. For Classifi cation system A, which of the following statements is true?

A All organisms in group 6 are in group 7.B All organisms in group 5 are in group 4.C All organisms in group 6 are in group 1.D All organisms in group 2 are in group 1.

2. For Classifi cation system A, which of the following statements is true?

F All organisms in group 3 are in group 2.G All organisms in group 3 are in group 4.H All organisms in group 3 are in group 1.I All organisms in group 3 are in every

other group.

3. For Classifi cation system B, which of the following statements is true?

A All organisms in group 1 are in group 6.B All organisms in group 6 are in group 1.C All organisms in group 3 are in group 1.D All organisms in group 2 are in group 5.

4. For Classifi cation system B, which of the following statements is true?

F All organisms in group 4 are in group 1, 2, and 5.

G All organisms in group 4 are in groups 3 and 5.

H All organisms in group 4 are in groups 5and 6.

I All organisms in group 4 are in groups 1, 5, and 6.

5. In Classifi cation system B, which group contains organisms that are not in group 1?

A 2B 4C 5D 6

INTERPRETING GRAPHICS

1 2 3 4 5 6 7

Classification system A

1

2

3 4 5 6

Classification system B

MATH

181