PlantsWhat Yoursquoll LearnChapter 21

What is a plant

Chapter 22 The Diversity of Plants

Chapter 23 Plant Structure and Function

Chapter 24 Reproduction in Plants

Unit 7 Review BioDigest and Standardized Test Practice

Why Itrsquos ImportantAlthough plants have different forms they have commonstructures and functions Over time adaptations of thesestructures and functions resulted in the diversity of plantsfound in the land and water biomes on Earth In thesebiomes plants are an essential resource for many of theother organisms that live there including humans Theseorganisms depend on plants for oxygen and directly orindirectly for food

9000ndash8001 BCWheat and barleyare the first plantsgrown as foodcrops

Understanding the PhotoPlant heights vary from a few millimetersto many meters These conifer trees cangrow to be hundreds of times taller thanthe ferns on the forest floor

556

300ndash291 BCTheophrastusoften called theldquoFather of Botanyrdquodescribes morethan 500 plants inhis book History ofPlants

1667Seed plants areclassified as mono-cots or dicotsaccording to thenumber of seedleaves (1 or 2) intheir seeds

1609ndash1610Spaniards establish a settlementthat will become present-daySanta Fe New Mexico

Carr CliftonMinden Pictures

cabdolglencoecomwebquest

0556-0557 UO7 BDOL-829900 8404 349 PM Page 556

1851It is discovered that alternation of genera-tions is part of the lifecycle of plants such asmosses

1986The first field trialsof a geneticallyaltered plant(tobacco) are carried out

1967Ten thousand-year-oldfrozen lupine seeds arediscovered in the YukonTerritory of CanadaThey germinate within48 hours after theythaw

557

1791The Bill of Rightsis ratified

1930The first packaged sliced bread is intro-duced in the US

0556-0557 UO7 BDOL-829900 8404 350 PM Page 557

558

What Yoursquoll Learn You will identify and evaluate

the structural adaptations of plants to their land environments

You will survey and identifythe major divisions of plants

Why Itrsquos ImportantPlants were the first multicellu-lar organisms to inhabit landover 440 million years ago Sincethen plants have developedinto a diverse group of organ-isms that help provide us withfood oxygen and shelter

Visit to bull study the entire chapter

onlinebull access Web Links for more

information and activities on plants

bull review content with theInteractive Tutor and self-check quizzes

What is a plantWhat is a plant

Because of plant adaptationsover time different plant speciesgrow in the different biomes onEarth The flowering plants andothers growing in this mountainmeadow have structural andphysiological adaptations thatensure their long-term survival inthis environment

Understandingthe Photo

Michelle WestmorlandEarth Scenes

cabdolglencoecom

0558-0558 C21CO BDOL-829900 8504 1200 AM Page 558

558

What Yoursquoll Learn You will identify and evaluate

the structural adaptations of plants to their land environments

You will survey and identifythe major divisions of plants

Why Itrsquos ImportantPlants were the first multicellu-lar organisms to inhabit landover 440 million years ago Sincethen plants have developedinto a diverse group of organ-isms that help provide us withfood oxygen and shelter

Visit to bull study the entire chapter

onlinebull access Web Links for more

information and activities on plants

bull review content with theInteractive Tutor and self-check quizzes

What is a plantWhat is a plant

Because of plant adaptationsover time different plant speciesgrow in the different biomes onEarth The flowering plants andothers growing in this mountainmeadow have structural andphysiological adaptations thatensure their long-term survival inthis environment

Understandingthe Photo

Michelle WestmorlandEarth Scenes

cabdolglencoecom

0558-0558 C21CO BDOL-829900 8504 1200 AM Page 558

Adapting to Life on Land

cuticle from theLatin word cutismeaning ldquoskinrdquoThe cuticle is theoutermost cover-ing of most plants

211 ADAPTING TO LIFE ON LAND 559

SECTION PREVIEWObjectivesCompare and contrastcharacteristics of algae andplantsIdentify and evaluatestructural adaptations of plants to their land environmentsDescribe the alternation of generations in landplants

Review Vocabularyadaptation any structure

behavior or internalprocess that enables anorganism to respond tostimuli and better survivein an environment (p 9)

New Vocabularycuticleleafrootstemvascular tissuevascular plantnonvascular plantseed

211

Origins of Plants What is a plant A plant is a multicellular eukaryote Most plants can

produce their own food in the form of glucose through the process ofphotosynthesis In addition plant cells have thick cell walls made of cel-lulose The stems and leaves of most plants have a waxy waterproofcoating called a cuticle (KYEWT ih kul)

Fossils and other geological evidence suggest that a billion years agoplants had not yet begun to appear on land No ferns mosses treesgrasses or wildflowers existed The land was barren except for some algaeat the edges of inland seas and oceans However the shallow waters thatcovered much of Earthrsquos surface at that time were teeming with bacteriaalgae and other protists as well as simple animals such as corals spongesjellyfish and worms Evidence indicates that green algae eventuallybecame adapted to life on land

Scientists hypothesize that all plants probably evolved from filamen-tous green algae that lived in the ancient oceans Some of the evidencefor their relationship can be found in modern members of both groups Green algae and plants have cell walls that contain celluloseBoth groups have the same types of chlorophyll used in photosynthe-sis and store food in the form of starch All other major groups oforganisms store food in the form of glycogen and other complexsugars andor lipids

Gametophyte

Sporophyte

Illustrate and Explain As you read Section 211 illustrate and explain eachstage under its tab

Alternation of Generations Make the following Foldable to help you illustrate and explain how the lives of all plants have two alternating stages

Draw a mark at the midpoint of a vertical sheet of paper along the side edge

Fold the outside edges in to touch at the midpoint mark

Label the tabs as shown

STEP 1

STEP 3

STEP 2

0559-0563 C21S1 BDOL-829900 8404 931 AM Page 559

BDOL-211

null

4819906

The first evidence of plants in thefossil record began to appear over440 million years ago These earlyplants were simple in structure anddid not have leaves They were prob-ably instrumental in turning barerock into rich soil The earliestknown plant fossils are those of psilo-phytes (SI luh fites) such as thoseshown in Figure 211

Explain how earlyland plants contributed to themovement of other plants to land

Adaptations in PlantsLife on land has advantages as well as

challenges All organisms need water tosurvive A filamentous green alga float-ing in a pond does not need to conservewater The alga is completely immersedin a bath of water and dissolved nutri-ents which it can absorb directly intoits cells For most land plants the onlyavailable supply of water and mineralsis in the soil and only the portion of theplant that penetrates the soil can absorbthese nutrients

When you studied protists youlearned that algae reproduce by releas-ing unprotected unicellular gametes

into the water where fertilization anddevelopment take place Land plantsevolved structural and physiologicaladaptations that help protect thegametes from drying out In someplants the sperm are released near theegg so they only have to travel a shortdistance Other plants have protectivestructures to ensure the survival of thegametes Land plants must also with-stand the forces of wind and weatherand be able to grow against the force ofgravity Over the past 443 million yearsor so plants have developed a hugevariety of adaptations that reflect boththe challenges and advantages of livingon land

Preventing water lossIf you run your fingers over the sur-

face of an apple a maple leaf or thestem of a houseplant yoursquoll probablyfind that it is smooth and slightly slip-pery Most fruits leaves and stems arecovered with a protective waxy layercalled the cuticle Waxes and oils arelipids which are biomolecules that donot dissolve in water The waxy cuticlecreates a barrier that helps prevent thewater in the plantrsquos tissues from evap-orating into the atmosphere

Figure 212 There is great diversity in leaf shapes andsizes Infer What advantage would abroad leaf like this cottonwood leafhave over a narrow leaf like a pineneedle

560 WHAT IS A PLANT

AA

BB

Figure 211 This fossil of Cooksoniais more than 400 mil-lion years old (A)Cooksonia was proba-bly one of the first vas-cular plants The planthad leafless stems (B)

(t)Harlan P Banks (b)Matt Meadows

0559-0563 C21S1 BDOL-829900 8404 932 AM Page 560

Carrying out photosynthesis

The leaf like the one in Figure212 is a plant organ that growsfrom a stem and usually is wherephotosynthesis occurs Leaves differgreatly in size and shape and theycan vary on the same plant Eachplant division has unique leaves orleaflike structures

Putting down roots

Most plants depend on the soil astheir primary source for water andother nutrients Plants can take inwater and nutrients from the soil withtheir roots In most plants a root is aplant organ that absorbs water andminerals usually from the soil Rootscontain tissues that transport thosenutrients to the stem Roots anchor aplant usually in the ground Someroots such as those of radishes orsweet potatoes accumulate starch andfunction as organs of storage Manypeople use these storage roots as afood source Find out more about theuses of plants on pages 1076ndash1079 inthe Focus On

In the MiniLab on this page exploreand evaluate some structural adapta-tions of plants that allow them to sur-vive on land Also practice your labskills by using a dissecting microscope

Transporting materials

Water moves from the roots of atree to its leaves and the sugars pro-duced in the leaves move to the rootsthrough the stem A stem is a plantorgan that provides support forgrowth as shown in Figure 213 Itcontains tissues for transporting foodwater and other materials from onepart of the plant to another Stemsalso can serve as organs for food stor-age In green stems some cells con-tain chlorophyll and can carry outphotosynthesis

Figure 213 Stems can be soft and flexible like the basil stemshown here (A) Other plantssuch as this sugar maple treehave strong thick stems thatprovide support and allow the tree to grow to great heights (B)

BB

AA

(t)Bill BeattyEarth Scenes (bl)Alan amp Linda DetrickPhoto Researchers (br)Lincoln NuttingPhoto Researchers

Apply ConceptsExamining Land PlantsLiverworts are considered to beone of the simplest of all landplants They show many of theadaptations that other land plantshave evolved that enable them tosurvive on a land environment

Procedure Examine a living or preserved sample of

Marchantia CAUTION Wear protective gloves when handling preserved materials

Note and record the following observations Is the plantunicellular or multicellular Does it have a top and bot-tom How do these differ Is it one cell in thickness ormany cells thick Does the plant seem to grow upright likea tree or close to the ground

Use a dissecting microscope to examine its top and bottomsurfaces Are tiny holes or pores present If you answerldquoyesrdquo which surface has pores

Analysis1 Predict How might having a multicellular thick body be

an advantage to life on land2 Observe Are rootlike structures present Evaluate the sig-

nificance of this adaptation to a land environment3 Infer What might be the role of any pores observed on

the plant Why is the location of the pores critical to sur-viving on a land environment

Marchantia

0559-0563 C21S1 BDOL-829900 8404 932 AM Page 561

The stems of most plants containvascular tissues Vascular tissues (VAS

kyuh lur) are made up of tubelike elon-gated cells through which water foodand other materials are transportedPlants that possess vascular tissues areknown as vascular plants Most of theplants you are familiar with includingpine and maple trees ferns rhododen-drons rye grasses English ivy and sun-flowers are vascular plants

Mosses and several other small less-familiar plants called hornworts and

liverworts are usually classified as non-vascular plants Nonvascular plantsdo not have vascular tissues The bod-ies of nonvascular plants are usually nomore than a few cells thick and waterand nutrients travel from one cell toanother by the processes of osmosisand diffusion

The evolution of vascular tissueswas an important structural adapta-tion for plants that allowed them tosurvive in the many habitats on landVascular plants can live farther awayfrom water than nonvascular plantsAlso because vascular tissues includethickened cells called fibers that helpsupport growth vascular plants cangrow much larger than nonvascularplants

Reproductive strategiesAdaptations in some land plants

include the evolution of seeds A seedis a plant organ that contains anembryo along with a food supply andis covered by a protective coat asshown in Figure 214 A seed pro-tects the embryo from drying out andalso can aid in its dispersal Recall thata spore consists only of a haploid cellwith a hard outer wall Land plantsreproduce by either spores or seeds

In non-seed plants which includemosses and ferns the sperm require afilm of water on the gametophyteplant to reach the egg In seed plantswhich include all conifers and flower-ing plants sperm reach the egg with-out using a film of water Thisdifference is one reason why non-seedplants require wetter habitats thanmost seed plants

Alternation of generationsAs in algae the lives of all plants

include two stages or alternating gen-erations as shown in Figure 215The gametophyte generation of aplant results in the development of

Seedcoat

Foodsupply

Embryo

Figure 214A seed consists of an embryoa food supply and a protec-tive seed coat

GAMETOPHYTE (n)

Spores (n)

Meiosis

SPOROPHYTE (2n)

Mitosis andcell division

Fertilization

Femalegamete (n)

Malegamete (n)

Figure 215 The lives of allplants consist oftwo generations

562 WHAT IS A PLANT

0559-0563 C21S1 BDOL-829900 8404 933 AM Page 562

Understanding Main Ideas1 Identify three characteristics that plants share

with algae2 Explain how the development of the cuticle and

the vascular system influenced the evolution ofplants on land

3 How do seeds and spores differ What are thebenefits of producing seeds

4 List the sequence of events involved in the alter-nation of generations in land plants Do all plantshave alternation of generations

Thinking Critically5 Explain why vascular plants are more likely to sur-

vive in a dry environment than nonvascular plants

6 Make and Use Tables Make a table of the differ-ent structural adaptations plants evolved thatallow them to live on land Include an evaluationof how each specific adaptation helped plants sur-vive on land For more help refer to Make and UseTables in the Skill Handbook

SKILL REVIEWSKILL REVIEW

211 ADAPTING TO LIFE ON LAND 563

gametes All cells of the gametophyteincluding the gametes are haploid (n)The sporophyte generation beginswith fertilization All cells of thesporophyte are diploid (2n) and areproduced by mitosis and cell divisionThe spores are produced in the sporo-phyte plant body by meiosis and aretherefore haploid (n)

In non-seed vascular plants such asferns spores have hard outer cover-ings Spores are released into theenvironment where they can growinto haploid gametophyte plantsThese plants produce male and femalegametes Following fertilization thesporophyte plant develops and growsfrom the gametophyte plant

In seed plants such as conifers andflowering plants spores develop insidethe sporophyte and become the game-tophytes The gametophytes consist ofonly a few cells Male and femalegametes are produced by these game-tophytes After fertilization a newsporophyte develops within a seedThe seed eventually is released and thenew sporophyte plant grows

Use the Problem-Solving Lab on thispage to explore further the differ-ences between the gametophyte andsporophyte generations of plants

Analyze InformationHow do gametophytes and sporophytes compareA plant has two stages in its life cycle The stages are calledthe gametophyte generation and the sporophyte generation

Solve the ProblemDiagram A shows the gametophyte generation of a plant This plant has a haploid chromosome number of 6 Examinethe diagram carefully and look for errorsDiagram B shows the sporophyte generation of a plant Thisplant has a diploid chromosome number of 12 Examine thediagram carefully and look for errors

Thinking Critically1 Observe Analyze diagram A identify errors and explain

why they are incorrect2 Observe Analyze diagram B identify errors and explain

why they are incorrect3 Use Models Illustrate diagrams A and B correctly so that

they connect to one another and form a complete life cyclediagram of a plant

Gametophyten = 6

Plant stage

Meiosis

Process Male sporen = 12

Female gameten = 12

Sporophyten = 12

Plant stage

Mitosis and cell division

Processes

Sporesn = 12

cabdolglencoecomself_check_quiz

0559-0563 C21S1 BDOL-829900 8604 1101 AM Page 563

The first evidence of plants in thefossil record began to appear over440 million years ago These earlyplants were simple in structure anddid not have leaves They were prob-ably instrumental in turning barerock into rich soil The earliestknown plant fossils are those of psilo-phytes (SI luh fites) such as thoseshown in Figure 211

Explain how earlyland plants contributed to themovement of other plants to land

Adaptations in PlantsLife on land has advantages as well as

challenges All organisms need water tosurvive A filamentous green alga float-ing in a pond does not need to conservewater The alga is completely immersedin a bath of water and dissolved nutri-ents which it can absorb directly intoits cells For most land plants the onlyavailable supply of water and mineralsis in the soil and only the portion of theplant that penetrates the soil can absorbthese nutrients

When you studied protists youlearned that algae reproduce by releas-ing unprotected unicellular gametes

into the water where fertilization anddevelopment take place Land plantsevolved structural and physiologicaladaptations that help protect thegametes from drying out In someplants the sperm are released near theegg so they only have to travel a shortdistance Other plants have protectivestructures to ensure the survival of thegametes Land plants must also with-stand the forces of wind and weatherand be able to grow against the force ofgravity Over the past 443 million yearsor so plants have developed a hugevariety of adaptations that reflect boththe challenges and advantages of livingon land

Preventing water lossIf you run your fingers over the sur-

face of an apple a maple leaf or thestem of a houseplant yoursquoll probablyfind that it is smooth and slightly slip-pery Most fruits leaves and stems arecovered with a protective waxy layercalled the cuticle Waxes and oils arelipids which are biomolecules that donot dissolve in water The waxy cuticlecreates a barrier that helps prevent thewater in the plantrsquos tissues from evap-orating into the atmosphere

Figure 212 There is great diversity in leaf shapes andsizes Infer What advantage would abroad leaf like this cottonwood leafhave over a narrow leaf like a pineneedle

560 WHAT IS A PLANT

AA

BB

Figure 211 This fossil of Cooksoniais more than 400 mil-lion years old (A)Cooksonia was proba-bly one of the first vas-cular plants The planthad leafless stems (B)

(t)Harlan P Banks (b)Matt Meadows

0559-0563 C21S1 BDOL-829900 8404 932 AM Page 560

Carrying out photosynthesis

The leaf like the one in Figure212 is a plant organ that growsfrom a stem and usually is wherephotosynthesis occurs Leaves differgreatly in size and shape and theycan vary on the same plant Eachplant division has unique leaves orleaflike structures

Putting down roots

Most plants depend on the soil astheir primary source for water andother nutrients Plants can take inwater and nutrients from the soil withtheir roots In most plants a root is aplant organ that absorbs water andminerals usually from the soil Rootscontain tissues that transport thosenutrients to the stem Roots anchor aplant usually in the ground Someroots such as those of radishes orsweet potatoes accumulate starch andfunction as organs of storage Manypeople use these storage roots as afood source Find out more about theuses of plants on pages 1076ndash1079 inthe Focus On

In the MiniLab on this page exploreand evaluate some structural adapta-tions of plants that allow them to sur-vive on land Also practice your labskills by using a dissecting microscope

Transporting materials

Water moves from the roots of atree to its leaves and the sugars pro-duced in the leaves move to the rootsthrough the stem A stem is a plantorgan that provides support forgrowth as shown in Figure 213 Itcontains tissues for transporting foodwater and other materials from onepart of the plant to another Stemsalso can serve as organs for food stor-age In green stems some cells con-tain chlorophyll and can carry outphotosynthesis

Figure 213 Stems can be soft and flexible like the basil stemshown here (A) Other plantssuch as this sugar maple treehave strong thick stems thatprovide support and allow the tree to grow to great heights (B)

BB

AA

(t)Bill BeattyEarth Scenes (bl)Alan amp Linda DetrickPhoto Researchers (br)Lincoln NuttingPhoto Researchers

Apply ConceptsExamining Land PlantsLiverworts are considered to beone of the simplest of all landplants They show many of theadaptations that other land plantshave evolved that enable them tosurvive on a land environment

Procedure Examine a living or preserved sample of

Marchantia CAUTION Wear protective gloves when handling preserved materials

Note and record the following observations Is the plantunicellular or multicellular Does it have a top and bot-tom How do these differ Is it one cell in thickness ormany cells thick Does the plant seem to grow upright likea tree or close to the ground

Use a dissecting microscope to examine its top and bottomsurfaces Are tiny holes or pores present If you answerldquoyesrdquo which surface has pores

Analysis1 Predict How might having a multicellular thick body be

an advantage to life on land2 Observe Are rootlike structures present Evaluate the sig-

nificance of this adaptation to a land environment3 Infer What might be the role of any pores observed on

the plant Why is the location of the pores critical to sur-viving on a land environment

Marchantia

0559-0563 C21S1 BDOL-829900 8404 932 AM Page 561

The stems of most plants containvascular tissues Vascular tissues (VAS

kyuh lur) are made up of tubelike elon-gated cells through which water foodand other materials are transportedPlants that possess vascular tissues areknown as vascular plants Most of theplants you are familiar with includingpine and maple trees ferns rhododen-drons rye grasses English ivy and sun-flowers are vascular plants

Mosses and several other small less-familiar plants called hornworts and

liverworts are usually classified as non-vascular plants Nonvascular plantsdo not have vascular tissues The bod-ies of nonvascular plants are usually nomore than a few cells thick and waterand nutrients travel from one cell toanother by the processes of osmosisand diffusion

The evolution of vascular tissueswas an important structural adapta-tion for plants that allowed them tosurvive in the many habitats on landVascular plants can live farther awayfrom water than nonvascular plantsAlso because vascular tissues includethickened cells called fibers that helpsupport growth vascular plants cangrow much larger than nonvascularplants

Reproductive strategiesAdaptations in some land plants

include the evolution of seeds A seedis a plant organ that contains anembryo along with a food supply andis covered by a protective coat asshown in Figure 214 A seed pro-tects the embryo from drying out andalso can aid in its dispersal Recall thata spore consists only of a haploid cellwith a hard outer wall Land plantsreproduce by either spores or seeds

In non-seed plants which includemosses and ferns the sperm require afilm of water on the gametophyteplant to reach the egg In seed plantswhich include all conifers and flower-ing plants sperm reach the egg with-out using a film of water Thisdifference is one reason why non-seedplants require wetter habitats thanmost seed plants

Alternation of generationsAs in algae the lives of all plants

include two stages or alternating gen-erations as shown in Figure 215The gametophyte generation of aplant results in the development of

Seedcoat

Foodsupply

Embryo

Figure 214A seed consists of an embryoa food supply and a protec-tive seed coat

GAMETOPHYTE (n)

Spores (n)

Meiosis

SPOROPHYTE (2n)

Mitosis andcell division

Fertilization

Femalegamete (n)

Malegamete (n)

Figure 215 The lives of allplants consist oftwo generations

562 WHAT IS A PLANT

0559-0563 C21S1 BDOL-829900 8404 933 AM Page 562

Understanding Main Ideas1 Identify three characteristics that plants share

with algae2 Explain how the development of the cuticle and

the vascular system influenced the evolution ofplants on land

3 How do seeds and spores differ What are thebenefits of producing seeds

4 List the sequence of events involved in the alter-nation of generations in land plants Do all plantshave alternation of generations

Thinking Critically5 Explain why vascular plants are more likely to sur-

vive in a dry environment than nonvascular plants

6 Make and Use Tables Make a table of the differ-ent structural adaptations plants evolved thatallow them to live on land Include an evaluationof how each specific adaptation helped plants sur-vive on land For more help refer to Make and UseTables in the Skill Handbook

SKILL REVIEWSKILL REVIEW

211 ADAPTING TO LIFE ON LAND 563

gametes All cells of the gametophyteincluding the gametes are haploid (n)The sporophyte generation beginswith fertilization All cells of thesporophyte are diploid (2n) and areproduced by mitosis and cell divisionThe spores are produced in the sporo-phyte plant body by meiosis and aretherefore haploid (n)

In non-seed vascular plants such asferns spores have hard outer cover-ings Spores are released into theenvironment where they can growinto haploid gametophyte plantsThese plants produce male and femalegametes Following fertilization thesporophyte plant develops and growsfrom the gametophyte plant

In seed plants such as conifers andflowering plants spores develop insidethe sporophyte and become the game-tophytes The gametophytes consist ofonly a few cells Male and femalegametes are produced by these game-tophytes After fertilization a newsporophyte develops within a seedThe seed eventually is released and thenew sporophyte plant grows

Use the Problem-Solving Lab on thispage to explore further the differ-ences between the gametophyte andsporophyte generations of plants

Analyze InformationHow do gametophytes and sporophytes compareA plant has two stages in its life cycle The stages are calledthe gametophyte generation and the sporophyte generation

Solve the ProblemDiagram A shows the gametophyte generation of a plant This plant has a haploid chromosome number of 6 Examinethe diagram carefully and look for errorsDiagram B shows the sporophyte generation of a plant Thisplant has a diploid chromosome number of 12 Examine thediagram carefully and look for errors

Thinking Critically1 Observe Analyze diagram A identify errors and explain

why they are incorrect2 Observe Analyze diagram B identify errors and explain

why they are incorrect3 Use Models Illustrate diagrams A and B correctly so that

they connect to one another and form a complete life cyclediagram of a plant

Gametophyten = 6

Plant stage

Meiosis

Process Male sporen = 12

Female gameten = 12

Sporophyten = 12

Plant stage

Mitosis and cell division

Processes

Sporesn = 12

cabdolglencoecomself_check_quiz

0559-0563 C21S1 BDOL-829900 8604 1101 AM Page 563

Carrying out photosynthesis

The leaf like the one in Figure212 is a plant organ that growsfrom a stem and usually is wherephotosynthesis occurs Leaves differgreatly in size and shape and theycan vary on the same plant Eachplant division has unique leaves orleaflike structures

Putting down roots

Most plants depend on the soil astheir primary source for water andother nutrients Plants can take inwater and nutrients from the soil withtheir roots In most plants a root is aplant organ that absorbs water andminerals usually from the soil Rootscontain tissues that transport thosenutrients to the stem Roots anchor aplant usually in the ground Someroots such as those of radishes orsweet potatoes accumulate starch andfunction as organs of storage Manypeople use these storage roots as afood source Find out more about theuses of plants on pages 1076ndash1079 inthe Focus On

In the MiniLab on this page exploreand evaluate some structural adapta-tions of plants that allow them to sur-vive on land Also practice your labskills by using a dissecting microscope

Transporting materials

Water moves from the roots of atree to its leaves and the sugars pro-duced in the leaves move to the rootsthrough the stem A stem is a plantorgan that provides support forgrowth as shown in Figure 213 Itcontains tissues for transporting foodwater and other materials from onepart of the plant to another Stemsalso can serve as organs for food stor-age In green stems some cells con-tain chlorophyll and can carry outphotosynthesis

Figure 213 Stems can be soft and flexible like the basil stemshown here (A) Other plantssuch as this sugar maple treehave strong thick stems thatprovide support and allow the tree to grow to great heights (B)

BB

AA

(t)Bill BeattyEarth Scenes (bl)Alan amp Linda DetrickPhoto Researchers (br)Lincoln NuttingPhoto Researchers

Apply ConceptsExamining Land PlantsLiverworts are considered to beone of the simplest of all landplants They show many of theadaptations that other land plantshave evolved that enable them tosurvive on a land environment

Procedure Examine a living or preserved sample of

Marchantia CAUTION Wear protective gloves when handling preserved materials

Note and record the following observations Is the plantunicellular or multicellular Does it have a top and bot-tom How do these differ Is it one cell in thickness ormany cells thick Does the plant seem to grow upright likea tree or close to the ground

Use a dissecting microscope to examine its top and bottomsurfaces Are tiny holes or pores present If you answerldquoyesrdquo which surface has pores

Analysis1 Predict How might having a multicellular thick body be

an advantage to life on land2 Observe Are rootlike structures present Evaluate the sig-

nificance of this adaptation to a land environment3 Infer What might be the role of any pores observed on

the plant Why is the location of the pores critical to sur-viving on a land environment

Marchantia

0559-0563 C21S1 BDOL-829900 8404 932 AM Page 561

The stems of most plants containvascular tissues Vascular tissues (VAS

kyuh lur) are made up of tubelike elon-gated cells through which water foodand other materials are transportedPlants that possess vascular tissues areknown as vascular plants Most of theplants you are familiar with includingpine and maple trees ferns rhododen-drons rye grasses English ivy and sun-flowers are vascular plants

Mosses and several other small less-familiar plants called hornworts and

liverworts are usually classified as non-vascular plants Nonvascular plantsdo not have vascular tissues The bod-ies of nonvascular plants are usually nomore than a few cells thick and waterand nutrients travel from one cell toanother by the processes of osmosisand diffusion

The evolution of vascular tissueswas an important structural adapta-tion for plants that allowed them tosurvive in the many habitats on landVascular plants can live farther awayfrom water than nonvascular plantsAlso because vascular tissues includethickened cells called fibers that helpsupport growth vascular plants cangrow much larger than nonvascularplants

Reproductive strategiesAdaptations in some land plants

include the evolution of seeds A seedis a plant organ that contains anembryo along with a food supply andis covered by a protective coat asshown in Figure 214 A seed pro-tects the embryo from drying out andalso can aid in its dispersal Recall thata spore consists only of a haploid cellwith a hard outer wall Land plantsreproduce by either spores or seeds

In non-seed plants which includemosses and ferns the sperm require afilm of water on the gametophyteplant to reach the egg In seed plantswhich include all conifers and flower-ing plants sperm reach the egg with-out using a film of water Thisdifference is one reason why non-seedplants require wetter habitats thanmost seed plants

Alternation of generationsAs in algae the lives of all plants

include two stages or alternating gen-erations as shown in Figure 215The gametophyte generation of aplant results in the development of

Seedcoat

Foodsupply

Embryo

Figure 214A seed consists of an embryoa food supply and a protec-tive seed coat

GAMETOPHYTE (n)

Spores (n)

Meiosis

SPOROPHYTE (2n)

Mitosis andcell division

Fertilization

Femalegamete (n)

Malegamete (n)

Figure 215 The lives of allplants consist oftwo generations

562 WHAT IS A PLANT

0559-0563 C21S1 BDOL-829900 8404 933 AM Page 562

Understanding Main Ideas1 Identify three characteristics that plants share

with algae2 Explain how the development of the cuticle and

the vascular system influenced the evolution ofplants on land

3 How do seeds and spores differ What are thebenefits of producing seeds

4 List the sequence of events involved in the alter-nation of generations in land plants Do all plantshave alternation of generations

Thinking Critically5 Explain why vascular plants are more likely to sur-

vive in a dry environment than nonvascular plants

6 Make and Use Tables Make a table of the differ-ent structural adaptations plants evolved thatallow them to live on land Include an evaluationof how each specific adaptation helped plants sur-vive on land For more help refer to Make and UseTables in the Skill Handbook

SKILL REVIEWSKILL REVIEW

211 ADAPTING TO LIFE ON LAND 563

gametes All cells of the gametophyteincluding the gametes are haploid (n)The sporophyte generation beginswith fertilization All cells of thesporophyte are diploid (2n) and areproduced by mitosis and cell divisionThe spores are produced in the sporo-phyte plant body by meiosis and aretherefore haploid (n)

In non-seed vascular plants such asferns spores have hard outer cover-ings Spores are released into theenvironment where they can growinto haploid gametophyte plantsThese plants produce male and femalegametes Following fertilization thesporophyte plant develops and growsfrom the gametophyte plant

In seed plants such as conifers andflowering plants spores develop insidethe sporophyte and become the game-tophytes The gametophytes consist ofonly a few cells Male and femalegametes are produced by these game-tophytes After fertilization a newsporophyte develops within a seedThe seed eventually is released and thenew sporophyte plant grows

Use the Problem-Solving Lab on thispage to explore further the differ-ences between the gametophyte andsporophyte generations of plants

Analyze InformationHow do gametophytes and sporophytes compareA plant has two stages in its life cycle The stages are calledthe gametophyte generation and the sporophyte generation

Solve the ProblemDiagram A shows the gametophyte generation of a plant This plant has a haploid chromosome number of 6 Examinethe diagram carefully and look for errorsDiagram B shows the sporophyte generation of a plant Thisplant has a diploid chromosome number of 12 Examine thediagram carefully and look for errors

Thinking Critically1 Observe Analyze diagram A identify errors and explain

why they are incorrect2 Observe Analyze diagram B identify errors and explain

why they are incorrect3 Use Models Illustrate diagrams A and B correctly so that

they connect to one another and form a complete life cyclediagram of a plant

Gametophyten = 6

Plant stage

Meiosis

Process Male sporen = 12

Female gameten = 12

Sporophyten = 12

Plant stage

Mitosis and cell division

Processes

Sporesn = 12

cabdolglencoecomself_check_quiz

0559-0563 C21S1 BDOL-829900 8604 1101 AM Page 563

The stems of most plants containvascular tissues Vascular tissues (VAS

kyuh lur) are made up of tubelike elon-gated cells through which water foodand other materials are transportedPlants that possess vascular tissues areknown as vascular plants Most of theplants you are familiar with includingpine and maple trees ferns rhododen-drons rye grasses English ivy and sun-flowers are vascular plants

Mosses and several other small less-familiar plants called hornworts and

liverworts are usually classified as non-vascular plants Nonvascular plantsdo not have vascular tissues The bod-ies of nonvascular plants are usually nomore than a few cells thick and waterand nutrients travel from one cell toanother by the processes of osmosisand diffusion

The evolution of vascular tissueswas an important structural adapta-tion for plants that allowed them tosurvive in the many habitats on landVascular plants can live farther awayfrom water than nonvascular plantsAlso because vascular tissues includethickened cells called fibers that helpsupport growth vascular plants cangrow much larger than nonvascularplants

Reproductive strategiesAdaptations in some land plants

include the evolution of seeds A seedis a plant organ that contains anembryo along with a food supply andis covered by a protective coat asshown in Figure 214 A seed pro-tects the embryo from drying out andalso can aid in its dispersal Recall thata spore consists only of a haploid cellwith a hard outer wall Land plantsreproduce by either spores or seeds

In non-seed plants which includemosses and ferns the sperm require afilm of water on the gametophyteplant to reach the egg In seed plantswhich include all conifers and flower-ing plants sperm reach the egg with-out using a film of water Thisdifference is one reason why non-seedplants require wetter habitats thanmost seed plants

Alternation of generationsAs in algae the lives of all plants

include two stages or alternating gen-erations as shown in Figure 215The gametophyte generation of aplant results in the development of

Seedcoat

Foodsupply

Embryo

Figure 214A seed consists of an embryoa food supply and a protec-tive seed coat

GAMETOPHYTE (n)

Spores (n)

Meiosis

SPOROPHYTE (2n)

Mitosis andcell division

Fertilization

Femalegamete (n)

Malegamete (n)

Figure 215 The lives of allplants consist oftwo generations

562 WHAT IS A PLANT

0559-0563 C21S1 BDOL-829900 8404 933 AM Page 562

Understanding Main Ideas1 Identify three characteristics that plants share

with algae2 Explain how the development of the cuticle and

the vascular system influenced the evolution ofplants on land

3 How do seeds and spores differ What are thebenefits of producing seeds

4 List the sequence of events involved in the alter-nation of generations in land plants Do all plantshave alternation of generations

Thinking Critically5 Explain why vascular plants are more likely to sur-

vive in a dry environment than nonvascular plants

6 Make and Use Tables Make a table of the differ-ent structural adaptations plants evolved thatallow them to live on land Include an evaluationof how each specific adaptation helped plants sur-vive on land For more help refer to Make and UseTables in the Skill Handbook

SKILL REVIEWSKILL REVIEW

211 ADAPTING TO LIFE ON LAND 563

gametes All cells of the gametophyteincluding the gametes are haploid (n)The sporophyte generation beginswith fertilization All cells of thesporophyte are diploid (2n) and areproduced by mitosis and cell divisionThe spores are produced in the sporo-phyte plant body by meiosis and aretherefore haploid (n)

In non-seed vascular plants such asferns spores have hard outer cover-ings Spores are released into theenvironment where they can growinto haploid gametophyte plantsThese plants produce male and femalegametes Following fertilization thesporophyte plant develops and growsfrom the gametophyte plant

In seed plants such as conifers andflowering plants spores develop insidethe sporophyte and become the game-tophytes The gametophytes consist ofonly a few cells Male and femalegametes are produced by these game-tophytes After fertilization a newsporophyte develops within a seedThe seed eventually is released and thenew sporophyte plant grows

Use the Problem-Solving Lab on thispage to explore further the differ-ences between the gametophyte andsporophyte generations of plants

Analyze InformationHow do gametophytes and sporophytes compareA plant has two stages in its life cycle The stages are calledthe gametophyte generation and the sporophyte generation

Solve the ProblemDiagram A shows the gametophyte generation of a plant This plant has a haploid chromosome number of 6 Examinethe diagram carefully and look for errorsDiagram B shows the sporophyte generation of a plant Thisplant has a diploid chromosome number of 12 Examine thediagram carefully and look for errors

Thinking Critically1 Observe Analyze diagram A identify errors and explain

why they are incorrect2 Observe Analyze diagram B identify errors and explain

why they are incorrect3 Use Models Illustrate diagrams A and B correctly so that

they connect to one another and form a complete life cyclediagram of a plant

Gametophyten = 6

Plant stage

Meiosis

Process Male sporen = 12

Female gameten = 12

Sporophyten = 12

Plant stage

Mitosis and cell division

Processes

Sporesn = 12

cabdolglencoecomself_check_quiz

0559-0563 C21S1 BDOL-829900 8604 1101 AM Page 563

Understanding Main Ideas1 Identify three characteristics that plants share

with algae2 Explain how the development of the cuticle and

the vascular system influenced the evolution ofplants on land

3 How do seeds and spores differ What are thebenefits of producing seeds

4 List the sequence of events involved in the alter-nation of generations in land plants Do all plantshave alternation of generations

Thinking Critically5 Explain why vascular plants are more likely to sur-

vive in a dry environment than nonvascular plants

6 Make and Use Tables Make a table of the differ-ent structural adaptations plants evolved thatallow them to live on land Include an evaluationof how each specific adaptation helped plants sur-vive on land For more help refer to Make and UseTables in the Skill Handbook

SKILL REVIEWSKILL REVIEW

211 ADAPTING TO LIFE ON LAND 563

gametes All cells of the gametophyteincluding the gametes are haploid (n)The sporophyte generation beginswith fertilization All cells of thesporophyte are diploid (2n) and areproduced by mitosis and cell divisionThe spores are produced in the sporo-phyte plant body by meiosis and aretherefore haploid (n)

In non-seed vascular plants such asferns spores have hard outer cover-ings Spores are released into theenvironment where they can growinto haploid gametophyte plantsThese plants produce male and femalegametes Following fertilization thesporophyte plant develops and growsfrom the gametophyte plant

In seed plants such as conifers andflowering plants spores develop insidethe sporophyte and become the game-tophytes The gametophytes consist ofonly a few cells Male and femalegametes are produced by these game-tophytes After fertilization a newsporophyte develops within a seedThe seed eventually is released and thenew sporophyte plant grows

Use the Problem-Solving Lab on thispage to explore further the differ-ences between the gametophyte andsporophyte generations of plants

Analyze InformationHow do gametophytes and sporophytes compareA plant has two stages in its life cycle The stages are calledthe gametophyte generation and the sporophyte generation

Solve the ProblemDiagram A shows the gametophyte generation of a plant This plant has a haploid chromosome number of 6 Examinethe diagram carefully and look for errorsDiagram B shows the sporophyte generation of a plant Thisplant has a diploid chromosome number of 12 Examine thediagram carefully and look for errors

Thinking Critically1 Observe Analyze diagram A identify errors and explain

why they are incorrect2 Observe Analyze diagram B identify errors and explain

why they are incorrect3 Use Models Illustrate diagrams A and B correctly so that

they connect to one another and form a complete life cyclediagram of a plant

Gametophyten = 6

Plant stage

Meiosis

Process Male sporen = 12

Female gameten = 12

Sporophyten = 12

Plant stage

Mitosis and cell division

Processes

Sporesn = 12

cabdolglencoecomself_check_quiz

0559-0563 C21S1 BDOL-829900 8604 1101 AM Page 563

212SECTION PREVIEWObjectivesDescribe the phylogenicrelationships among divi-sions of plantsIdentify the plant king-dom divisions

Review Vocabularyevolution gradual change

in an organism throughadaptations over time(p 10)

New Vocabularyfrondcone

564 WHAT IS A PLANT

Different Plants in Different PlacesUsing Prior Knowledge Members of theplant kingdom are found worldwidePlants survive on the coldtundra in arid deserts inoceans in freshwaterlakes and in your com-munity If you have evertraveled far from homeyou may have seen plantsthat do not grow natu-rally where you live Evennear your home you mayhave noticed that someplants grow only in sunny locations andothers thrive in shady damp areas Infer What structural and physiological adapta-tions do plants such as the cactus and mosses shownhere have that would allow them to survive in different biomes on Earth Compare and then evaluate the significance of these adaptations

Phylogeny of Plants Many geological and climate changes have taken place since the first

plants became adapted to life on land Landmasses have moved fromplace to place over Earthrsquos surface climates have changed and bodies ofwater have formed and disappeared Hundreds of thousands of plantspecies evolved and countless numbers of these became extinct as condi-tions continually changed These processes of evolution and extinctioncontinue to be affected by local and global changes As plant speciesevolved in this changing landscape they retained many of their old char-acteristics and also developed new ones These processes of evolution andextinction continue today

Some botanists use plant characteristics to classify plants into divi-sions Recall that a plant division is similar to a phylum in other king-doms The highlights of plant evolution include origins of plants fromgreen algae the production of a waxy cuticle the development of vascu-lar tissue and roots and the production of seeds The production ofseeds can be used as a basis to separate the divisions into two groupsmdashnon-seed plants and seed plants

Survey of the Plant Kingdom

A Saguaro cactus (right)and mosses (left)

Movement oflandmassesLandmassescontinually moveover Earthrsquossurface Earthrsquosouter layer isbroken into hugesections calledplates Theseplates move slowlyover the materialunderneath Manyscientists thinkthat the motion ofhot material deepwithin Earthgenerates theforces that causeplates to move

(l)Paul WakefieldTony Stone Images (r)David WrobelVisuals Unlimited

PhysicalScience

Connection

0564-0575 C21S2 BDOL-829900 8404 913 PM Page 564

BDOL-212

null

44797583

Non-seed PlantsThe divisions of non-seed plants are

shown in Figure 216 These plantsproduce hard-walled reproductive cellscalled spores Non-seed plants includevascular and nonvascular organisms

Hepaticophyta Hepaticophytes (heh PAH tih koh

fites) include small plants commonlycalled liverworts Their flattenedbodies resemble the lobes of an ani-malrsquos liver Liverworts are nonvascu-lar plants that grow only in moistenvironments Water and nutrients

move throughout a liverwort byosmosis and diffusion Studies com-paring the biochemistry of differentplant divisions suggest that liverwortsmay be the ancestors of all plants

There are two kinds of liverwortsthallose liverworts and leafy liver-worts Thallose liverworts have abroad body that looks like a lobedleaf Leafy liverworts are creepingplants with three rows of thin leavesattached to a stem

Anthocerophyta Anthocerophytes (an THOH ser

oh fites) are also small thallose plants

212 SURVEY OF THE PLANT KINGDOM 565

hepato- from theGreek word heparmeaning ldquoliverrdquoHepaticophyteshave liver-shapedgametophytes

Figure 216The plant kingdom includes severaldivisions of non-seed plants

Selaginella a spike moss is a lycophyte Lycophytesare vascular plants adaptedto moist environments

A

Sphagnum is a bryophyteIt grows in peat bogs

D

Psilotum sporophyteshave simple stemsbut no leaves or roots

G

Equisetum is an arthrophyteIt has roots stems andleaves but the stems arehollow and appear jointed

C

Anthoceros ahornwort is ananthocerophyteIt is found inmoist shadyhabitats

F

Marchantia is ahepaticophyte It isfound on damp rocks

E

All ferns are pterophytesThe cinnamon fernOsmunda cinnamomeagrows in swampy habitatsthroughout the UnitedStates

B

(tl)David T RobertsNaturersquos ImagesPhoto Researchers (tc)Jim StrawserGrant Heilman Inc (tr)James H RobinsonEarth Scenes (bl)Patti MurrayEarth Scenes (bcl)Gregory K ScottPhoto Researchers (bcr)Runk-SchoenbergerGrant Heilman Inc (br)Doug WechslerEarth Scenes

0564-0575 C21S2 BDOL-829900 8404 942 AM Page 565

The sporophytes of these plantswhich resemble the horns of an ani-mal give the plants their commonnamemdashhornworts These nonvascu-lar plants grow in damp shady habi-tats and rely on osmosis and diffusionto transport nutrients

Bryophyta Bryophytes (BRI uh fites) the

mosses are nonvascular plants thatrely on osmosis and diffusion totransport materials However somemosses have elongated cells that con-duct water and sugars Moss plantsare usually less than 5 cm tall andhave leaflike structures that are usu-ally only one to two cells thick Theirspores are formed in capsules

Psilophyta Psilophytes known as whisk ferns

consist of thin green stems Thepsilophytes are unique vascular plantsbecause they have neither roots norleaves Small scales that are flat rigidoverlapping structures cover eachstem The two known genera ofpsilophytes are tropical or subtropi-cal Only one genus is found in thesouthern United States

Describe the maindifference between bryophytes andpsilophytes

Lycophyta Lycophytes (LI koh fites) the club

mosses are vascular plants adaptedprimarily to moist environmentsLycophytes have stems roots andleaves Their leaves although verysmall contain vascular tissue Speciesexisting today are usually less than 25 cm high but their ancestors grewas tall as 30 m and formed a large partof the vegetation of Paleozoic forestsThe plants of these ancient forestshave become part of the coal that is now used by people for fuel

566 WHAT IS A PLANT

AA

BB

Compare and ContrastLooking at Modern and Fossil Plants Many modern plantshave relatives that are known only from the fossil record Aremodern plants similar to their fossil relatives Are there anydifferences

Procedure Examine a preserved or living sample of Lycopodium a

club moss CAUTION Wear protective gloves when han-dling preserved material

Note and record the following observationsa Does the plant grow flat or upright like a tree b Describe the appearance of its leaves and its stemc Measure the plantrsquos height and diameter in centimeters

Repeat step 2 for diagram A a fossil relative$ Repeat steps 1ndash3 using a preserved or living sample of

Equisetum a horsetail and diagram B a fossil relative

Analysis1 Compare and Contrast Describe the similarities and dif-

ferences between Lycopodium and Lepidodendron Do yourobservations justify their closeness as relatives Explain

2 Compare and Contrast Describe the similarities and dif-ferences between Equisetum and Calamites Do yourobservations justify their closeness as relatives Explain

2 meters1 meter

20 meters

30 meters

Representation ofLepidodendron

Representationof Calamites

0564-0575 C21S2 BDOL-829900 8404 943 AM Page 566

212 SURVEY OF THE PLANT KINGDOM 567

Try MiniLab 212 to explore the simi-larities and differences between mod-ern and fossil lycophytes

ArthrophytaArthrophytes (AR throh fites) the

horsetails are vascular plants Theyhave hollow jointed stems sur-rounded by whorls of scalelike leavesThe cells covering the stems of somearthrophytes contain large deposits ofsilica Although primarily a fossilgroup about 15 species of arthro-phytes exist today All modern horse-tails are small but their fossil relativeswere the size of trees

Pterophyta Pterophytes (TER oh fites) ferns are

the most well-known and diversegroup of non-seed vascular plantsFerns were abundant in Paleozoic andMesozoic forests They have leavescalled fronds that vary in length from1 cm to 500 cm The large size andcomplexity of fronds is one differencebetween pterophytes and other groupsof seedless vascular plants Althoughferns are found nearly everywheremost grow in the tropics

Seed Plants Seed plants produce seeds which

in a dry environment are a moreeffective means of reproduction thanspores A seed consists of an embry-onic plant and a food supply coveredby a hard protective seed coat Allseed plants have vascular tissues InProblem-Solving Lab 212 you cancompare a characteristic common toseed plants and non-seed plants

CycadophytaCycads (SI kuds) were abundant

during the Mesozoic Era Todaythere are about 100 species of cycadsThey are palmlike trees with scaly

trunks and can be short or more than20 m in height Cycads produce maleand female cones on separate treesCones are scaly structures that sup-port male or female reproductivestructures Cycad cones can be aslong as 1 m Seeds are produced infemale cones Male cones produceclouds of pollen

Apply ConceptsWhat trend in size is seen with gametophyte and sporo-phyte generations All plants undergo alternation of gener-ations There is a specific trend however that occurs in size asone goes from one plant division to the next

Solve the Problem The following graph shows the trend that occurs within theplant kingdom as one compares the size of sporophyte andgametophyte generations in three major divisions

Thinking Critically1 Analyze Describe the trend that occurs to the size of the

gametophyte generation as one moves from bryophytes toanthophytes

2 Analyze Describe the trend that occurs to the size of thesporophyte generation as one moves from bryophytes toanthophytes

3 Predict Estimate the size of the gametophyte generationcompared with the sporophyte generation ina Coniferophyta Explainb Lycophyta Explain

4 Infer You are looking at a giant redwood tree Whichgeneration is it and how do you know

Gam

etop

hyte

gen

erat

ion

Spor

ophy

te g

ener

atio

n

Increasing sporophyte size

BRY

OPH

YTA

PTER

OPH

YTA

AN

THO

PHY

TA

Decreasing gametophyte size

0564-0575 C21S2 BDOL-829900 8404 944 AM Page 567

GnetophytaThere are three genera of gneto-

phytes (NEE toh fites) and each has dis-tinct characteristics Gnetum (NEE tum)includes about 30 species of tropicaltrees and climbing vines There areabout 35 Ephedra (eh FEH dra) species

that grow as shrubby plants in desertand arid regions Welwitschia (welWITCH ee uh) has only one specieswhich is found in the deserts of south-west Africa Its leaves grow from thebase of a short stem that resembles alarge shallow cap

568 WHAT IS A PLANT

Table 211 Seed Plant Divisions

Division Example Common Names Characteristics

Cycadophyta Sago palm cycad Cycads grow in tropical or subtropical zamia dioon environments These plants are slow-growing

trees with unbranched trunks Their leaves are palmlike Seeds are produced in cones onfemale plants

Gnetophyta Joint fir Gnetum Gnetophytes are usually found in desert or Welwitschia arid environments but some are tropical

They exhibit diverse growth habits from vines to low-growing forms These plants produce seeds in conelike structures

Ginkgophyta Ginkgo maiden- Ginkgoes are tolerant of a wide range of hair tree habitats from urban to open environments

These trees drop their leaves in the fall Their seeds are surrounded by soft fruitlike structures

Coniferophyta Pine spruce Conifers grow in a wide range of habitats juniper redwood Depending on the species conifers can be tall fir yew hemlock trees or ground-covering shrubs The leaves arborvitae cedar of conifers are needlelike or scalelike Seeds

develop in cones or berrylike structures

Anthophyta Rice tomato rose Anthophytes are found worldwide The divisioncorn basil apple includes a great diversity of growth habits oak grass cattail forms and sizes All anthophytes produce grape bluebell flowers from which dry or fleshy fruits with

one or more seeds develop

(1)WH HodgePeter Arnold Inc (2)Gunter ZieslerPeter Arnold Inc (3)Jim StrawserGrant Heilman Inc (4)Runk-SchoenbergerGrant Heilman Inc (5)Jeff LeporePhoto Researchers

0564-0575 C21S2 BDOL-829900 8404 944 AM Page 568

GinkgophytaThis division has only one living

species Ginkgo biloba a distinctivetree with small fan-shaped leavesLike cycads ginkgoes (GING kohs)have male and female reproductivestructures on separate trees Theseeds produced on female trees havean unpleasant smell so ginkgoesplanted in city parks are usually maletrees Ginkgoes are hardy and resist-ant to insects and to air pollution

ConiferophytaThese are the conifers (KAH nuh

furz) cone-bearing trees such as pinefir cypress and redwood Conifersare vascular seed plants that produceseeds in cones Species of conifers canbe identified by the characteristics oftheir cones or leaves that are needle-like or scaly You can learn moreabout how to identify conifers in theBioLab at the end of the chapter

Bristlecone pines the oldestknown living trees in the world aremembers of this plant divisionAnother type of conifer the Pacificyew is a source of cancer-fightingdrugs Read more about medicinalplants in the Connection to Health atthe end of this chapter

AnthophytaAnthophytes (AN thoh fites) com-

monly called the flowering plants

are the largest most diverse group of seed plants living on Earth Thereare approximately 250 000 species of anthophytes Fossils of theAnthophyta date to early in theCretaceous Period Unlike conifersanthophytes produce flowers fromwhich fruits develop like those inFigure 217 A fruit usually containsone or more seeds This division hastwo classes the monocotyledons (mahnuh kah tul EE dunz) and dicotyledons(di kah tul EE dunz) You will learnmore about the distinctions betweenmonocots and dicots when you readabout anthophyte tissues in Chapter 23

Table 211 lists some informationabout the divisions of seed plants Doyou recognize any of the commonnames of the plants Can you add tothe list of common names

Understanding Main Ideas1 What is the primary difference between the seeds

of conifers and anthophytes2 Why are seeds an important structural adapta-

tion What plant divisions produce seeds Whichplant divisions do not produce seeds

3 What structural adaptation allows pterophytes togrow larger than bryophytes

4 Compare and contrast anthophytes and anthocerophytes

Thinking Critically5 In which division would you expect to find apple

trees Why

6 Get the Big Picture Make a table of the plantdivisions Label columns Division Seed PlantsNon-seed Plants Vascular Plants NonvascularPlants and Seeds in Fruits For more help refer toGet the Big Picture in the Skill Handbook

SKILL REVIEWSKILL REVIEW

212 SURVEY OF THE PLANT KINGDOM 569

conifero- from theLatin word conifermeaning ldquoconebearingrdquo Manyplants in the divi-sion Coniferophyta produce theirseeds on cones

Figure 217These fruits and seedsdeveloped from flowersList Can you namethree vegetables thatare really fruits

Matt Meadows

cabdolglencoecomself_check_quiz

0564-0575 C21S2 BDOL-829900 8404 914 PM Page 569

Non-seed PlantsThe divisions of non-seed plants are

shown in Figure 216 These plantsproduce hard-walled reproductive cellscalled spores Non-seed plants includevascular and nonvascular organisms

Hepaticophyta Hepaticophytes (heh PAH tih koh

fites) include small plants commonlycalled liverworts Their flattenedbodies resemble the lobes of an ani-malrsquos liver Liverworts are nonvascu-lar plants that grow only in moistenvironments Water and nutrients

move throughout a liverwort byosmosis and diffusion Studies com-paring the biochemistry of differentplant divisions suggest that liverwortsmay be the ancestors of all plants

There are two kinds of liverwortsthallose liverworts and leafy liver-worts Thallose liverworts have abroad body that looks like a lobedleaf Leafy liverworts are creepingplants with three rows of thin leavesattached to a stem

Anthocerophyta Anthocerophytes (an THOH ser

oh fites) are also small thallose plants

212 SURVEY OF THE PLANT KINGDOM 565

hepato- from theGreek word heparmeaning ldquoliverrdquoHepaticophyteshave liver-shapedgametophytes

Figure 216The plant kingdom includes severaldivisions of non-seed plants

Selaginella a spike moss is a lycophyte Lycophytesare vascular plants adaptedto moist environments

A

Sphagnum is a bryophyteIt grows in peat bogs

D

Psilotum sporophyteshave simple stemsbut no leaves or roots

G

Equisetum is an arthrophyteIt has roots stems andleaves but the stems arehollow and appear jointed

C

Anthoceros ahornwort is ananthocerophyteIt is found inmoist shadyhabitats

F

Marchantia is ahepaticophyte It isfound on damp rocks

E

All ferns are pterophytesThe cinnamon fernOsmunda cinnamomeagrows in swampy habitatsthroughout the UnitedStates

B

(tl)David T RobertsNaturersquos ImagesPhoto Researchers (tc)Jim StrawserGrant Heilman Inc (tr)James H RobinsonEarth Scenes (bl)Patti MurrayEarth Scenes (bcl)Gregory K ScottPhoto Researchers (bcr)Runk-SchoenbergerGrant Heilman Inc (br)Doug WechslerEarth Scenes

0564-0575 C21S2 BDOL-829900 8404 942 AM Page 565

The sporophytes of these plantswhich resemble the horns of an ani-mal give the plants their commonnamemdashhornworts These nonvascu-lar plants grow in damp shady habi-tats and rely on osmosis and diffusionto transport nutrients

Bryophyta Bryophytes (BRI uh fites) the

mosses are nonvascular plants thatrely on osmosis and diffusion totransport materials However somemosses have elongated cells that con-duct water and sugars Moss plantsare usually less than 5 cm tall andhave leaflike structures that are usu-ally only one to two cells thick Theirspores are formed in capsules

Psilophyta Psilophytes known as whisk ferns

consist of thin green stems Thepsilophytes are unique vascular plantsbecause they have neither roots norleaves Small scales that are flat rigidoverlapping structures cover eachstem The two known genera ofpsilophytes are tropical or subtropi-cal Only one genus is found in thesouthern United States

Describe the maindifference between bryophytes andpsilophytes

Lycophyta Lycophytes (LI koh fites) the club

mosses are vascular plants adaptedprimarily to moist environmentsLycophytes have stems roots andleaves Their leaves although verysmall contain vascular tissue Speciesexisting today are usually less than 25 cm high but their ancestors grewas tall as 30 m and formed a large partof the vegetation of Paleozoic forestsThe plants of these ancient forestshave become part of the coal that is now used by people for fuel

566 WHAT IS A PLANT

AA

BB

Compare and ContrastLooking at Modern and Fossil Plants Many modern plantshave relatives that are known only from the fossil record Aremodern plants similar to their fossil relatives Are there anydifferences

Procedure Examine a preserved or living sample of Lycopodium a

club moss CAUTION Wear protective gloves when han-dling preserved material

Note and record the following observationsa Does the plant grow flat or upright like a tree b Describe the appearance of its leaves and its stemc Measure the plantrsquos height and diameter in centimeters

Repeat step 2 for diagram A a fossil relative$ Repeat steps 1ndash3 using a preserved or living sample of

Equisetum a horsetail and diagram B a fossil relative

Analysis1 Compare and Contrast Describe the similarities and dif-

ferences between Lycopodium and Lepidodendron Do yourobservations justify their closeness as relatives Explain

2 Compare and Contrast Describe the similarities and dif-ferences between Equisetum and Calamites Do yourobservations justify their closeness as relatives Explain

2 meters1 meter

20 meters

30 meters

Representation ofLepidodendron

Representationof Calamites

0564-0575 C21S2 BDOL-829900 8404 943 AM Page 566

212 SURVEY OF THE PLANT KINGDOM 567

Try MiniLab 212 to explore the simi-larities and differences between mod-ern and fossil lycophytes

ArthrophytaArthrophytes (AR throh fites) the

horsetails are vascular plants Theyhave hollow jointed stems sur-rounded by whorls of scalelike leavesThe cells covering the stems of somearthrophytes contain large deposits ofsilica Although primarily a fossilgroup about 15 species of arthro-phytes exist today All modern horse-tails are small but their fossil relativeswere the size of trees

Pterophyta Pterophytes (TER oh fites) ferns are

the most well-known and diversegroup of non-seed vascular plantsFerns were abundant in Paleozoic andMesozoic forests They have leavescalled fronds that vary in length from1 cm to 500 cm The large size andcomplexity of fronds is one differencebetween pterophytes and other groupsof seedless vascular plants Althoughferns are found nearly everywheremost grow in the tropics

Seed Plants Seed plants produce seeds which

in a dry environment are a moreeffective means of reproduction thanspores A seed consists of an embry-onic plant and a food supply coveredby a hard protective seed coat Allseed plants have vascular tissues InProblem-Solving Lab 212 you cancompare a characteristic common toseed plants and non-seed plants

CycadophytaCycads (SI kuds) were abundant

during the Mesozoic Era Todaythere are about 100 species of cycadsThey are palmlike trees with scaly

trunks and can be short or more than20 m in height Cycads produce maleand female cones on separate treesCones are scaly structures that sup-port male or female reproductivestructures Cycad cones can be aslong as 1 m Seeds are produced infemale cones Male cones produceclouds of pollen

Apply ConceptsWhat trend in size is seen with gametophyte and sporo-phyte generations All plants undergo alternation of gener-ations There is a specific trend however that occurs in size asone goes from one plant division to the next

Solve the Problem The following graph shows the trend that occurs within theplant kingdom as one compares the size of sporophyte andgametophyte generations in three major divisions

Thinking Critically1 Analyze Describe the trend that occurs to the size of the

gametophyte generation as one moves from bryophytes toanthophytes

2 Analyze Describe the trend that occurs to the size of thesporophyte generation as one moves from bryophytes toanthophytes

3 Predict Estimate the size of the gametophyte generationcompared with the sporophyte generation ina Coniferophyta Explainb Lycophyta Explain

4 Infer You are looking at a giant redwood tree Whichgeneration is it and how do you know

Gam

etop

hyte

gen

erat

ion

Spor

ophy

te g

ener

atio

n

Increasing sporophyte size

BRY

OPH

YTA

PTER

OPH

YTA

AN

THO

PHY

TA

Decreasing gametophyte size

0564-0575 C21S2 BDOL-829900 8404 944 AM Page 567

GnetophytaThere are three genera of gneto-

phytes (NEE toh fites) and each has dis-tinct characteristics Gnetum (NEE tum)includes about 30 species of tropicaltrees and climbing vines There areabout 35 Ephedra (eh FEH dra) species

that grow as shrubby plants in desertand arid regions Welwitschia (welWITCH ee uh) has only one specieswhich is found in the deserts of south-west Africa Its leaves grow from thebase of a short stem that resembles alarge shallow cap

568 WHAT IS A PLANT

Table 211 Seed Plant Divisions

Division Example Common Names Characteristics

Cycadophyta Sago palm cycad Cycads grow in tropical or subtropical zamia dioon environments These plants are slow-growing

trees with unbranched trunks Their leaves are palmlike Seeds are produced in cones onfemale plants

Gnetophyta Joint fir Gnetum Gnetophytes are usually found in desert or Welwitschia arid environments but some are tropical

They exhibit diverse growth habits from vines to low-growing forms These plants produce seeds in conelike structures

Ginkgophyta Ginkgo maiden- Ginkgoes are tolerant of a wide range of hair tree habitats from urban to open environments

These trees drop their leaves in the fall Their seeds are surrounded by soft fruitlike structures

Coniferophyta Pine spruce Conifers grow in a wide range of habitats juniper redwood Depending on the species conifers can be tall fir yew hemlock trees or ground-covering shrubs The leaves arborvitae cedar of conifers are needlelike or scalelike Seeds

develop in cones or berrylike structures

Anthophyta Rice tomato rose Anthophytes are found worldwide The divisioncorn basil apple includes a great diversity of growth habits oak grass cattail forms and sizes All anthophytes produce grape bluebell flowers from which dry or fleshy fruits with

one or more seeds develop

(1)WH HodgePeter Arnold Inc (2)Gunter ZieslerPeter Arnold Inc (3)Jim StrawserGrant Heilman Inc (4)Runk-SchoenbergerGrant Heilman Inc (5)Jeff LeporePhoto Researchers

0564-0575 C21S2 BDOL-829900 8404 944 AM Page 568

GinkgophytaThis division has only one living

species Ginkgo biloba a distinctivetree with small fan-shaped leavesLike cycads ginkgoes (GING kohs)have male and female reproductivestructures on separate trees Theseeds produced on female trees havean unpleasant smell so ginkgoesplanted in city parks are usually maletrees Ginkgoes are hardy and resist-ant to insects and to air pollution

ConiferophytaThese are the conifers (KAH nuh

furz) cone-bearing trees such as pinefir cypress and redwood Conifersare vascular seed plants that produceseeds in cones Species of conifers canbe identified by the characteristics oftheir cones or leaves that are needle-like or scaly You can learn moreabout how to identify conifers in theBioLab at the end of the chapter

Bristlecone pines the oldestknown living trees in the world aremembers of this plant divisionAnother type of conifer the Pacificyew is a source of cancer-fightingdrugs Read more about medicinalplants in the Connection to Health atthe end of this chapter

AnthophytaAnthophytes (AN thoh fites) com-

monly called the flowering plants

are the largest most diverse group of seed plants living on Earth Thereare approximately 250 000 species of anthophytes Fossils of theAnthophyta date to early in theCretaceous Period Unlike conifersanthophytes produce flowers fromwhich fruits develop like those inFigure 217 A fruit usually containsone or more seeds This division hastwo classes the monocotyledons (mahnuh kah tul EE dunz) and dicotyledons(di kah tul EE dunz) You will learnmore about the distinctions betweenmonocots and dicots when you readabout anthophyte tissues in Chapter 23

Table 211 lists some informationabout the divisions of seed plants Doyou recognize any of the commonnames of the plants Can you add tothe list of common names

Understanding Main Ideas1 What is the primary difference between the seeds

of conifers and anthophytes2 Why are seeds an important structural adapta-

tion What plant divisions produce seeds Whichplant divisions do not produce seeds

3 What structural adaptation allows pterophytes togrow larger than bryophytes

4 Compare and contrast anthophytes and anthocerophytes

Thinking Critically5 In which division would you expect to find apple

trees Why

6 Get the Big Picture Make a table of the plantdivisions Label columns Division Seed PlantsNon-seed Plants Vascular Plants NonvascularPlants and Seeds in Fruits For more help refer toGet the Big Picture in the Skill Handbook

SKILL REVIEWSKILL REVIEW

212 SURVEY OF THE PLANT KINGDOM 569

conifero- from theLatin word conifermeaning ldquoconebearingrdquo Manyplants in the divi-sion Coniferophyta produce theirseeds on cones

Figure 217These fruits and seedsdeveloped from flowersList Can you namethree vegetables thatare really fruits

Matt Meadows

cabdolglencoecomself_check_quiz

0564-0575 C21S2 BDOL-829900 8404 914 PM Page 569

The sporophytes of these plantswhich resemble the horns of an ani-mal give the plants their commonnamemdashhornworts These nonvascu-lar plants grow in damp shady habi-tats and rely on osmosis and diffusionto transport nutrients

Bryophyta Bryophytes (BRI uh fites) the

mosses are nonvascular plants thatrely on osmosis and diffusion totransport materials However somemosses have elongated cells that con-duct water and sugars Moss plantsare usually less than 5 cm tall andhave leaflike structures that are usu-ally only one to two cells thick Theirspores are formed in capsules

Psilophyta Psilophytes known as whisk ferns

consist of thin green stems Thepsilophytes are unique vascular plantsbecause they have neither roots norleaves Small scales that are flat rigidoverlapping structures cover eachstem The two known genera ofpsilophytes are tropical or subtropi-cal Only one genus is found in thesouthern United States

Describe the maindifference between bryophytes andpsilophytes

Lycophyta Lycophytes (LI koh fites) the club

mosses are vascular plants adaptedprimarily to moist environmentsLycophytes have stems roots andleaves Their leaves although verysmall contain vascular tissue Speciesexisting today are usually less than 25 cm high but their ancestors grewas tall as 30 m and formed a large partof the vegetation of Paleozoic forestsThe plants of these ancient forestshave become part of the coal that is now used by people for fuel

566 WHAT IS A PLANT

AA

BB

Compare and ContrastLooking at Modern and Fossil Plants Many modern plantshave relatives that are known only from the fossil record Aremodern plants similar to their fossil relatives Are there anydifferences

Procedure Examine a preserved or living sample of Lycopodium a

club moss CAUTION Wear protective gloves when han-dling preserved material

Note and record the following observationsa Does the plant grow flat or upright like a tree b Describe the appearance of its leaves and its stemc Measure the plantrsquos height and diameter in centimeters

Repeat step 2 for diagram A a fossil relative$ Repeat steps 1ndash3 using a preserved or living sample of

Equisetum a horsetail and diagram B a fossil relative

Analysis1 Compare and Contrast Describe the similarities and dif-

ferences between Lycopodium and Lepidodendron Do yourobservations justify their closeness as relatives Explain

2 Compare and Contrast Describe the similarities and dif-ferences between Equisetum and Calamites Do yourobservations justify their closeness as relatives Explain

2 meters1 meter

20 meters

30 meters

Representation ofLepidodendron

Representationof Calamites

0564-0575 C21S2 BDOL-829900 8404 943 AM Page 566

212 SURVEY OF THE PLANT KINGDOM 567

Try MiniLab 212 to explore the simi-larities and differences between mod-ern and fossil lycophytes

ArthrophytaArthrophytes (AR throh fites) the

horsetails are vascular plants Theyhave hollow jointed stems sur-rounded by whorls of scalelike leavesThe cells covering the stems of somearthrophytes contain large deposits ofsilica Although primarily a fossilgroup about 15 species of arthro-phytes exist today All modern horse-tails are small but their fossil relativeswere the size of trees

Pterophyta Pterophytes (TER oh fites) ferns are

the most well-known and diversegroup of non-seed vascular plantsFerns were abundant in Paleozoic andMesozoic forests They have leavescalled fronds that vary in length from1 cm to 500 cm The large size andcomplexity of fronds is one differencebetween pterophytes and other groupsof seedless vascular plants Althoughferns are found nearly everywheremost grow in the tropics

Seed Plants Seed plants produce seeds which

in a dry environment are a moreeffective means of reproduction thanspores A seed consists of an embry-onic plant and a food supply coveredby a hard protective seed coat Allseed plants have vascular tissues InProblem-Solving Lab 212 you cancompare a characteristic common toseed plants and non-seed plants

CycadophytaCycads (SI kuds) were abundant

during the Mesozoic Era Todaythere are about 100 species of cycadsThey are palmlike trees with scaly

trunks and can be short or more than20 m in height Cycads produce maleand female cones on separate treesCones are scaly structures that sup-port male or female reproductivestructures Cycad cones can be aslong as 1 m Seeds are produced infemale cones Male cones produceclouds of pollen

Apply ConceptsWhat trend in size is seen with gametophyte and sporo-phyte generations All plants undergo alternation of gener-ations There is a specific trend however that occurs in size asone goes from one plant division to the next

Solve the Problem The following graph shows the trend that occurs within theplant kingdom as one compares the size of sporophyte andgametophyte generations in three major divisions

Thinking Critically1 Analyze Describe the trend that occurs to the size of the

gametophyte generation as one moves from bryophytes toanthophytes

2 Analyze Describe the trend that occurs to the size of thesporophyte generation as one moves from bryophytes toanthophytes

3 Predict Estimate the size of the gametophyte generationcompared with the sporophyte generation ina Coniferophyta Explainb Lycophyta Explain

4 Infer You are looking at a giant redwood tree Whichgeneration is it and how do you know

Gam

etop

hyte

gen

erat

ion

Spor

ophy

te g

ener

atio

n

Increasing sporophyte size

BRY

OPH

YTA

PTER

OPH

YTA

AN

THO

PHY

TA

Decreasing gametophyte size

0564-0575 C21S2 BDOL-829900 8404 944 AM Page 567

GnetophytaThere are three genera of gneto-

phytes (NEE toh fites) and each has dis-tinct characteristics Gnetum (NEE tum)includes about 30 species of tropicaltrees and climbing vines There areabout 35 Ephedra (eh FEH dra) species

that grow as shrubby plants in desertand arid regions Welwitschia (welWITCH ee uh) has only one specieswhich is found in the deserts of south-west Africa Its leaves grow from thebase of a short stem that resembles alarge shallow cap

568 WHAT IS A PLANT

Table 211 Seed Plant Divisions

Division Example Common Names Characteristics

Cycadophyta Sago palm cycad Cycads grow in tropical or subtropical zamia dioon environments These plants are slow-growing

trees with unbranched trunks Their leaves are palmlike Seeds are produced in cones onfemale plants

Gnetophyta Joint fir Gnetum Gnetophytes are usually found in desert or Welwitschia arid environments but some are tropical

They exhibit diverse growth habits from vines to low-growing forms These plants produce seeds in conelike structures

Ginkgophyta Ginkgo maiden- Ginkgoes are tolerant of a wide range of hair tree habitats from urban to open environments

These trees drop their leaves in the fall Their seeds are surrounded by soft fruitlike structures

Coniferophyta Pine spruce Conifers grow in a wide range of habitats juniper redwood Depending on the species conifers can be tall fir yew hemlock trees or ground-covering shrubs The leaves arborvitae cedar of conifers are needlelike or scalelike Seeds

develop in cones or berrylike structures

Anthophyta Rice tomato rose Anthophytes are found worldwide The divisioncorn basil apple includes a great diversity of growth habits oak grass cattail forms and sizes All anthophytes produce grape bluebell flowers from which dry or fleshy fruits with

one or more seeds develop

(1)WH HodgePeter Arnold Inc (2)Gunter ZieslerPeter Arnold Inc (3)Jim StrawserGrant Heilman Inc (4)Runk-SchoenbergerGrant Heilman Inc (5)Jeff LeporePhoto Researchers

0564-0575 C21S2 BDOL-829900 8404 944 AM Page 568

GinkgophytaThis division has only one living

species Ginkgo biloba a distinctivetree with small fan-shaped leavesLike cycads ginkgoes (GING kohs)have male and female reproductivestructures on separate trees Theseeds produced on female trees havean unpleasant smell so ginkgoesplanted in city parks are usually maletrees Ginkgoes are hardy and resist-ant to insects and to air pollution

ConiferophytaThese are the conifers (KAH nuh

furz) cone-bearing trees such as pinefir cypress and redwood Conifersare vascular seed plants that produceseeds in cones Species of conifers canbe identified by the characteristics oftheir cones or leaves that are needle-like or scaly You can learn moreabout how to identify conifers in theBioLab at the end of the chapter

Bristlecone pines the oldestknown living trees in the world aremembers of this plant divisionAnother type of conifer the Pacificyew is a source of cancer-fightingdrugs Read more about medicinalplants in the Connection to Health atthe end of this chapter

AnthophytaAnthophytes (AN thoh fites) com-

monly called the flowering plants

are the largest most diverse group of seed plants living on Earth Thereare approximately 250 000 species of anthophytes Fossils of theAnthophyta date to early in theCretaceous Period Unlike conifersanthophytes produce flowers fromwhich fruits develop like those inFigure 217 A fruit usually containsone or more seeds This division hastwo classes the monocotyledons (mahnuh kah tul EE dunz) and dicotyledons(di kah tul EE dunz) You will learnmore about the distinctions betweenmonocots and dicots when you readabout anthophyte tissues in Chapter 23

Table 211 lists some informationabout the divisions of seed plants Doyou recognize any of the commonnames of the plants Can you add tothe list of common names

Understanding Main Ideas1 What is the primary difference between the seeds

of conifers and anthophytes2 Why are seeds an important structural adapta-

tion What plant divisions produce seeds Whichplant divisions do not produce seeds

3 What structural adaptation allows pterophytes togrow larger than bryophytes

4 Compare and contrast anthophytes and anthocerophytes

Thinking Critically5 In which division would you expect to find apple

trees Why

6 Get the Big Picture Make a table of the plantdivisions Label columns Division Seed PlantsNon-seed Plants Vascular Plants NonvascularPlants and Seeds in Fruits For more help refer toGet the Big Picture in the Skill Handbook

SKILL REVIEWSKILL REVIEW

212 SURVEY OF THE PLANT KINGDOM 569

conifero- from theLatin word conifermeaning ldquoconebearingrdquo Manyplants in the divi-sion Coniferophyta produce theirseeds on cones

Figure 217These fruits and seedsdeveloped from flowersList Can you namethree vegetables thatare really fruits

Matt Meadows

cabdolglencoecomself_check_quiz

0564-0575 C21S2 BDOL-829900 8404 914 PM Page 569

212 SURVEY OF THE PLANT KINGDOM 567

Try MiniLab 212 to explore the simi-larities and differences between mod-ern and fossil lycophytes

ArthrophytaArthrophytes (AR throh fites) the

horsetails are vascular plants Theyhave hollow jointed stems sur-rounded by whorls of scalelike leavesThe cells covering the stems of somearthrophytes contain large deposits ofsilica Although primarily a fossilgroup about 15 species of arthro-phytes exist today All modern horse-tails are small but their fossil relativeswere the size of trees

Pterophyta Pterophytes (TER oh fites) ferns are

the most well-known and diversegroup of non-seed vascular plantsFerns were abundant in Paleozoic andMesozoic forests They have leavescalled fronds that vary in length from1 cm to 500 cm The large size andcomplexity of fronds is one differencebetween pterophytes and other groupsof seedless vascular plants Althoughferns are found nearly everywheremost grow in the tropics

Seed Plants Seed plants produce seeds which

in a dry environment are a moreeffective means of reproduction thanspores A seed consists of an embry-onic plant and a food supply coveredby a hard protective seed coat Allseed plants have vascular tissues InProblem-Solving Lab 212 you cancompare a characteristic common toseed plants and non-seed plants

CycadophytaCycads (SI kuds) were abundant

during the Mesozoic Era Todaythere are about 100 species of cycadsThey are palmlike trees with scaly

trunks and can be short or more than20 m in height Cycads produce maleand female cones on separate treesCones are scaly structures that sup-port male or female reproductivestructures Cycad cones can be aslong as 1 m Seeds are produced infemale cones Male cones produceclouds of pollen

Apply ConceptsWhat trend in size is seen with gametophyte and sporo-phyte generations All plants undergo alternation of gener-ations There is a specific trend however that occurs in size asone goes from one plant division to the next

Solve the Problem The following graph shows the trend that occurs within theplant kingdom as one compares the size of sporophyte andgametophyte generations in three major divisions

Thinking Critically1 Analyze Describe the trend that occurs to the size of the

gametophyte generation as one moves from bryophytes toanthophytes

2 Analyze Describe the trend that occurs to the size of thesporophyte generation as one moves from bryophytes toanthophytes

3 Predict Estimate the size of the gametophyte generationcompared with the sporophyte generation ina Coniferophyta Explainb Lycophyta Explain

4 Infer You are looking at a giant redwood tree Whichgeneration is it and how do you know

Gam

etop

hyte

gen

erat

ion

Spor

ophy

te g

ener

atio

n

Increasing sporophyte size

BRY

OPH

YTA

PTER

OPH

YTA

AN

THO

PHY

TA

Decreasing gametophyte size

0564-0575 C21S2 BDOL-829900 8404 944 AM Page 567

GnetophytaThere are three genera of gneto-

phytes (NEE toh fites) and each has dis-tinct characteristics Gnetum (NEE tum)includes about 30 species of tropicaltrees and climbing vines There areabout 35 Ephedra (eh FEH dra) species

that grow as shrubby plants in desertand arid regions Welwitschia (welWITCH ee uh) has only one specieswhich is found in the deserts of south-west Africa Its leaves grow from thebase of a short stem that resembles alarge shallow cap

568 WHAT IS A PLANT

Table 211 Seed Plant Divisions

Division Example Common Names Characteristics

Cycadophyta Sago palm cycad Cycads grow in tropical or subtropical zamia dioon environments These plants are slow-growing

trees with unbranched trunks Their leaves are palmlike Seeds are produced in cones onfemale plants

Gnetophyta Joint fir Gnetum Gnetophytes are usually found in desert or Welwitschia arid environments but some are tropical

They exhibit diverse growth habits from vines to low-growing forms These plants produce seeds in conelike structures

Ginkgophyta Ginkgo maiden- Ginkgoes are tolerant of a wide range of hair tree habitats from urban to open environments

These trees drop their leaves in the fall Their seeds are surrounded by soft fruitlike structures

Coniferophyta Pine spruce Conifers grow in a wide range of habitats juniper redwood Depending on the species conifers can be tall fir yew hemlock trees or ground-covering shrubs The leaves arborvitae cedar of conifers are needlelike or scalelike Seeds

develop in cones or berrylike structures

Anthophyta Rice tomato rose Anthophytes are found worldwide The divisioncorn basil apple includes a great diversity of growth habits oak grass cattail forms and sizes All anthophytes produce grape bluebell flowers from which dry or fleshy fruits with

one or more seeds develop

(1)WH HodgePeter Arnold Inc (2)Gunter ZieslerPeter Arnold Inc (3)Jim StrawserGrant Heilman Inc (4)Runk-SchoenbergerGrant Heilman Inc (5)Jeff LeporePhoto Researchers

0564-0575 C21S2 BDOL-829900 8404 944 AM Page 568

GinkgophytaThis division has only one living

species Ginkgo biloba a distinctivetree with small fan-shaped leavesLike cycads ginkgoes (GING kohs)have male and female reproductivestructures on separate trees Theseeds produced on female trees havean unpleasant smell so ginkgoesplanted in city parks are usually maletrees Ginkgoes are hardy and resist-ant to insects and to air pollution

ConiferophytaThese are the conifers (KAH nuh

furz) cone-bearing trees such as pinefir cypress and redwood Conifersare vascular seed plants that produceseeds in cones Species of conifers canbe identified by the characteristics oftheir cones or leaves that are needle-like or scaly You can learn moreabout how to identify conifers in theBioLab at the end of the chapter

Bristlecone pines the oldestknown living trees in the world aremembers of this plant divisionAnother type of conifer the Pacificyew is a source of cancer-fightingdrugs Read more about medicinalplants in the Connection to Health atthe end of this chapter

AnthophytaAnthophytes (AN thoh fites) com-

monly called the flowering plants

are the largest most diverse group of seed plants living on Earth Thereare approximately 250 000 species of anthophytes Fossils of theAnthophyta date to early in theCretaceous Period Unlike conifersanthophytes produce flowers fromwhich fruits develop like those inFigure 217 A fruit usually containsone or more seeds This division hastwo classes the monocotyledons (mahnuh kah tul EE dunz) and dicotyledons(di kah tul EE dunz) You will learnmore about the distinctions betweenmonocots and dicots when you readabout anthophyte tissues in Chapter 23

Table 211 lists some informationabout the divisions of seed plants Doyou recognize any of the commonnames of the plants Can you add tothe list of common names

Understanding Main Ideas1 What is the primary difference between the seeds

of conifers and anthophytes2 Why are seeds an important structural adapta-

tion What plant divisions produce seeds Whichplant divisions do not produce seeds

3 What structural adaptation allows pterophytes togrow larger than bryophytes

4 Compare and contrast anthophytes and anthocerophytes

Thinking Critically5 In which division would you expect to find apple

trees Why

6 Get the Big Picture Make a table of the plantdivisions Label columns Division Seed PlantsNon-seed Plants Vascular Plants NonvascularPlants and Seeds in Fruits For more help refer toGet the Big Picture in the Skill Handbook

SKILL REVIEWSKILL REVIEW

212 SURVEY OF THE PLANT KINGDOM 569

conifero- from theLatin word conifermeaning ldquoconebearingrdquo Manyplants in the divi-sion Coniferophyta produce theirseeds on cones

Figure 217These fruits and seedsdeveloped from flowersList Can you namethree vegetables thatare really fruits

Matt Meadows

cabdolglencoecomself_check_quiz

0564-0575 C21S2 BDOL-829900 8404 914 PM Page 569

GnetophytaThere are three genera of gneto-

phytes (NEE toh fites) and each has dis-tinct characteristics Gnetum (NEE tum)includes about 30 species of tropicaltrees and climbing vines There areabout 35 Ephedra (eh FEH dra) species

that grow as shrubby plants in desertand arid regions Welwitschia (welWITCH ee uh) has only one specieswhich is found in the deserts of south-west Africa Its leaves grow from thebase of a short stem that resembles alarge shallow cap

568 WHAT IS A PLANT

Table 211 Seed Plant Divisions

Division Example Common Names Characteristics

Cycadophyta Sago palm cycad Cycads grow in tropical or subtropical zamia dioon environments These plants are slow-growing

trees with unbranched trunks Their leaves are palmlike Seeds are produced in cones onfemale plants

Gnetophyta Joint fir Gnetum Gnetophytes are usually found in desert or Welwitschia arid environments but some are tropical

They exhibit diverse growth habits from vines to low-growing forms These plants produce seeds in conelike structures

Ginkgophyta Ginkgo maiden- Ginkgoes are tolerant of a wide range of hair tree habitats from urban to open environments

These trees drop their leaves in the fall Their seeds are surrounded by soft fruitlike structures

Coniferophyta Pine spruce Conifers grow in a wide range of habitats juniper redwood Depending on the species conifers can be tall fir yew hemlock trees or ground-covering shrubs The leaves arborvitae cedar of conifers are needlelike or scalelike Seeds

develop in cones or berrylike structures

Anthophyta Rice tomato rose Anthophytes are found worldwide The divisioncorn basil apple includes a great diversity of growth habits oak grass cattail forms and sizes All anthophytes produce grape bluebell flowers from which dry or fleshy fruits with

one or more seeds develop

(1)WH HodgePeter Arnold Inc (2)Gunter ZieslerPeter Arnold Inc (3)Jim StrawserGrant Heilman Inc (4)Runk-SchoenbergerGrant Heilman Inc (5)Jeff LeporePhoto Researchers

0564-0575 C21S2 BDOL-829900 8404 944 AM Page 568

GinkgophytaThis division has only one living

species Ginkgo biloba a distinctivetree with small fan-shaped leavesLike cycads ginkgoes (GING kohs)have male and female reproductivestructures on separate trees Theseeds produced on female trees havean unpleasant smell so ginkgoesplanted in city parks are usually maletrees Ginkgoes are hardy and resist-ant to insects and to air pollution

ConiferophytaThese are the conifers (KAH nuh

furz) cone-bearing trees such as pinefir cypress and redwood Conifersare vascular seed plants that produceseeds in cones Species of conifers canbe identified by the characteristics oftheir cones or leaves that are needle-like or scaly You can learn moreabout how to identify conifers in theBioLab at the end of the chapter

Bristlecone pines the oldestknown living trees in the world aremembers of this plant divisionAnother type of conifer the Pacificyew is a source of cancer-fightingdrugs Read more about medicinalplants in the Connection to Health atthe end of this chapter

AnthophytaAnthophytes (AN thoh fites) com-

monly called the flowering plants

are the largest most diverse group of seed plants living on Earth Thereare approximately 250 000 species of anthophytes Fossils of theAnthophyta date to early in theCretaceous Period Unlike conifersanthophytes produce flowers fromwhich fruits develop like those inFigure 217 A fruit usually containsone or more seeds This division hastwo classes the monocotyledons (mahnuh kah tul EE dunz) and dicotyledons(di kah tul EE dunz) You will learnmore about the distinctions betweenmonocots and dicots when you readabout anthophyte tissues in Chapter 23

Table 211 lists some informationabout the divisions of seed plants Doyou recognize any of the commonnames of the plants Can you add tothe list of common names

Understanding Main Ideas1 What is the primary difference between the seeds

of conifers and anthophytes2 Why are seeds an important structural adapta-

tion What plant divisions produce seeds Whichplant divisions do not produce seeds

3 What structural adaptation allows pterophytes togrow larger than bryophytes

4 Compare and contrast anthophytes and anthocerophytes

Thinking Critically5 In which division would you expect to find apple

trees Why

6 Get the Big Picture Make a table of the plantdivisions Label columns Division Seed PlantsNon-seed Plants Vascular Plants NonvascularPlants and Seeds in Fruits For more help refer toGet the Big Picture in the Skill Handbook

SKILL REVIEWSKILL REVIEW

212 SURVEY OF THE PLANT KINGDOM 569

conifero- from theLatin word conifermeaning ldquoconebearingrdquo Manyplants in the divi-sion Coniferophyta produce theirseeds on cones

Figure 217These fruits and seedsdeveloped from flowersList Can you namethree vegetables thatare really fruits

Matt Meadows

cabdolglencoecomself_check_quiz

0564-0575 C21S2 BDOL-829900 8404 914 PM Page 569

GinkgophytaThis division has only one living

species Ginkgo biloba a distinctivetree with small fan-shaped leavesLike cycads ginkgoes (GING kohs)have male and female reproductivestructures on separate trees Theseeds produced on female trees havean unpleasant smell so ginkgoesplanted in city parks are usually maletrees Ginkgoes are hardy and resist-ant to insects and to air pollution

ConiferophytaThese are the conifers (KAH nuh

furz) cone-bearing trees such as pinefir cypress and redwood Conifersare vascular seed plants that produceseeds in cones Species of conifers canbe identified by the characteristics oftheir cones or leaves that are needle-like or scaly You can learn moreabout how to identify conifers in theBioLab at the end of the chapter

Bristlecone pines the oldestknown living trees in the world aremembers of this plant divisionAnother type of conifer the Pacificyew is a source of cancer-fightingdrugs Read more about medicinalplants in the Connection to Health atthe end of this chapter

AnthophytaAnthophytes (AN thoh fites) com-

monly called the flowering plants

are the largest most diverse group of seed plants living on Earth Thereare approximately 250 000 species of anthophytes Fossils of theAnthophyta date to early in theCretaceous Period Unlike conifersanthophytes produce flowers fromwhich fruits develop like those inFigure 217 A fruit usually containsone or more seeds This division hastwo classes the monocotyledons (mahnuh kah tul EE dunz) and dicotyledons(di kah tul EE dunz) You will learnmore about the distinctions betweenmonocots and dicots when you readabout anthophyte tissues in Chapter 23

Table 211 lists some informationabout the divisions of seed plants Doyou recognize any of the commonnames of the plants Can you add tothe list of common names

Understanding Main Ideas1 What is the primary difference between the seeds

of conifers and anthophytes2 Why are seeds an important structural adapta-

tion What plant divisions produce seeds Whichplant divisions do not produce seeds

3 What structural adaptation allows pterophytes togrow larger than bryophytes

4 Compare and contrast anthophytes and anthocerophytes

Thinking Critically5 In which division would you expect to find apple

trees Why

6 Get the Big Picture Make a table of the plantdivisions Label columns Division Seed PlantsNon-seed Plants Vascular Plants NonvascularPlants and Seeds in Fruits For more help refer toGet the Big Picture in the Skill Handbook

SKILL REVIEWSKILL REVIEW

212 SURVEY OF THE PLANT KINGDOM 569

conifero- from theLatin word conifermeaning ldquoconebearingrdquo Manyplants in the divi-sion Coniferophyta produce theirseeds on cones

Figure 217These fruits and seedsdeveloped from flowersList Can you namethree vegetables thatare really fruits

Matt Meadows

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Before YouBegin

Each conifer species has aunique cone The leaves ofconifer species also havedifferent characteristicsHow would you identify aconifer You would proba-bly use a dichotomous keyDichotomous keys list fea-tures of related organismsin a way that allows youto determine each organ-ismrsquos scientific nameBelow is an example froma dichotomous key thatmight be used to identifytrees

Needles grouped in bundlesNeedles not grouped in

bundlesNeedlelike leavesFlat thin leavesLeaves composed of three

or more leafletsLeaves not made up of

leaflets

Arborvitae

Hemlock

570 WHAT IS A PLANT

Pine needles

How can you make a keyfor identifying conifers

ProblemWhat characteristics can be used to create a dichotomous key for identifying different kinds of conifers

HypothesesState your hypothesis according to the kinds of characteristics you predict will best serve to distinguish among several conifer groups Explain your reasoning

ObjectivesIn this BioLab you will Compare structures of several different

conifer specimens Identify which characteristics can be used

to distinguish one conifer from another Develop a model of a hierarchical classification system

(division genus species) based on similarities and differ-ences using taxonomic nomenclature

Possible Materialstwigs branches and cones from several different conifersthat have been identified for you

Safety PrecautionsCAUTION Always wash your hands after handling biologicalmaterials Always wear goggles in the lab

Skill HandbookIf you need help with this lab refer to the Skill Handbook

PREPARATIONPREPARATION

Matt Meadows

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212 SURVEY OF THE PLANT KINGDOM 571

1 Make a list of characteristics that could be included inyour key You might consider using shape color sizehabitat or other factors

2 Determine which of those characteristics would be mosthelpful in classifying your conifers

3 Determine in what order the characteristicsshould appear in your key

4 Decide how to describe each characteristic

Check the Plan1 The traits described at each step in a key

are often pairs of contrasting characteris-tics For example the first step in a keyto conifers might compare ldquoneedlesgrouped in bundlesrdquo with ldquoneedlesattached singlyrdquo

2 Someone who is not familiar with conifer identification should be able to use your keyto correctly identify any conifer it includes

3 Make sure your teacher has approved your experimental plan before you proceed further

4 Carry out your plan by creating your key5 Return all conifer specimens to

the location specified by your teacher for reuse by otherstudents Wash your hands thoroughly

CLEANUP AND DISPOSAL

PLAN THE EXPERIMENTPLAN THE EXPERIMENT

Spruce

ANALYZE AND CONCLUDEANALYZE AND CONCLUDE

1 Check Your Hypothesis Have someoneoutside your lab group use your key to iden-tify a conifer specimen If he or she cannotidentify it try to determine what the prob-lem is and make improvements to your key

2 Relate Concepts Give one or more exam-ples of situations in which a dichotomouskey would be a useful tool

3 Is there only one correctway to design a dichotomous key for yourspecimens Explain why or why not

ERROR ANALYSIS

Project Design a different dichotomous keythat would also work to identify your speci-mens You may expand your key to includeadditional conifers

Web Links To find out more about conifers visit

(l)Scott NielsenDRK Photo (r)Michel ViardPeter Arnold Inc

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212 SURVEY OF THE PLANT KINGDOM 571

1 Make a list of characteristics that could be included inyour key You might consider using shape color sizehabitat or other factors

2 Determine which of those characteristics would be mosthelpful in classifying your conifers

3 Determine in what order the characteristicsshould appear in your key

4 Decide how to describe each characteristic

Check the Plan1 The traits described at each step in a key

are often pairs of contrasting characteris-tics For example the first step in a keyto conifers might compare ldquoneedlesgrouped in bundlesrdquo with ldquoneedlesattached singlyrdquo

2 Someone who is not familiar with conifer identification should be able to use your keyto correctly identify any conifer it includes

3 Make sure your teacher has approved your experimental plan before you proceed further

4 Carry out your plan by creating your key5 Return all conifer specimens to

the location specified by your teacher for reuse by otherstudents Wash your hands thoroughly

CLEANUP AND DISPOSAL

PLAN THE EXPERIMENTPLAN THE EXPERIMENT

Spruce

ANALYZE AND CONCLUDEANALYZE AND CONCLUDE

1 Check Your Hypothesis Have someoneoutside your lab group use your key to iden-tify a conifer specimen If he or she cannotidentify it try to determine what the prob-lem is and make improvements to your key

2 Relate Concepts Give one or more exam-ples of situations in which a dichotomouskey would be a useful tool

3 Is there only one correctway to design a dichotomous key for yourspecimens Explain why or why not

ERROR ANALYSIS

Project Design a different dichotomous keythat would also work to identify your speci-mens You may expand your key to includeadditional conifers

Web Links To find out more about conifers visit

(l)Scott NielsenDRK Photo (r)Michel ViardPeter Arnold Inc

cabdolglencoecomconifers

0564-0575 C21S2 BDOL-829900 8404 1009 PM Page 571

572 WHAT IS A PLANT

Medicines fromPlants

What comes to mind when you hear theword plant A vase full of flowers A fruit

and vegetable garden An evergreen forestAlthough these examples are what most peoplethink of when they hear the word plant plantsprovide us with much more than bouquets foodand lumber Nearly 80 percent of the worldrsquospopulation relies on medications derived fromplants In fact just fewer than 100 plants providethe active ingredients used in the ten dozen or soplant-derived medicines currently on the market

For thousands of years the words plants andmedicines were used synonymously In the fifthcentury AD doctors of the Byzantine Empireused the autumn crocus to effectively treatrheumatism and arthritis Hundreds of yearsago certain groups of Native North Americansused the rhizomes of the mayapple as a laxativea remedy for intestinal worms and as a topicaltreatment for warts and other skin growths Theoils from peppermint leaves have long been usedto settle an upset stomach Lotions containingthe liquid from the plant Aloe vera are often usedto relieve the pain associated with minor burnsincluding sunburn ldquoHerbalrdquo medicines haveagain begun to play an important role in so-called modern medicine

AspirinmdashThe wonder drug Evidence sug-gests that almost 2500 years ago a Greek physi-cian named Hippocrates used a substance fromthe bark of a white willow tree to treat minorpains and fever The substance which is calledsalicin unfortunately upset the stomach Researchin the late 1800s led to the discovery of acetylsali-cylic acid (ah SEE till sa lih SIH lick bull A sid) oraspirin Aspirin originally was developed bychemist Felix Hoffmann to relieve the joint discomfort associated with rheumatism Salicylic

acidmdasha major component of aspirinmdashwas finallysynthesized in the laboratory in the early 1900sSince then aspirinrsquos use has become widespread

New drugs for cancer Drugs that fight two types of cancermdashHodgkinrsquos disease and leukemiamdashhave been derived from theMadagascar rosy periwinkle Drugs producedfrom the needles and bark of the Pacific yewhave been used to treat breast ovarian lung andother cancers Although the interest in medicinalplants by consumers medical experts and phar-maceutical companies is growing it is estimatedthat less than five percent of the 250 000 differ-ent flowering plant species have been studied fortheir potential use in the field of medicine

Madagascar rosy periwinkle

Project Identify a plant not mentioned in thisfeature that is known to have medicinal proper-ties Research the plantrsquos geographic distributionon Earth its use(s) the active ingredient derivedfrom the plant and whether or not a syntheticform of the active ingredient is available for useAs a class compile all findings and create a class-room display

To find out more about medicines derivedfrom plants visit

Richard ShiellEarth Scenes

cabdolglencoecomhealth

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Section 211

Section 212

Key Concepts Plants are multicellular eukaryotes with

cells that have cell walls containing cellu-lose A waterproof cuticle covers the outer surface of most plants Most plantsundergo photosynthesis which producesglucose a form of food

All plants on Earth probably evolved from filamentous green algae that lived inancient oceans The first plants to eventu-ally move from water to land probablywere leafless forms

Adaptations for life on land include a cuticle the development of leaves rootsstems and vascular tissues alternation ofgenerations and the evolution of the seed

Vocabularycuticle (p 559)leaf (p 561)nonvascular plant

(p 562)root (p 561)seed (p 562)stem (p 561)vascular plant (p 562)vascular tissue (p 562)

Key Concepts The plant kingdom is grouped into major

categories called divisions Nonvascular plants are in the divisions

Anthocerophyta Hepaticophyta andBryophyta They reproduce mainly byusing spores Nonvascular plants do notproduce seeds

Non-seed vascular plants are in the divi-sions Psilophyta Lycophyta Arthrophytaand Pterophyta These plants have tissuesthat conduct water and other materials and reproduce mainly by spores

Vascular seed plants in the divisionsCycadophyta Gnetophyta Ginkgophytaand Coniferophyta produce seeds on conesMale cones and female cones can be onseparate plants or the same plant

The division Anthophyta includes vascularseed-producing plants that flower Fruitswith seeds develop from flowers Antho-phytes are divided into two groupsmdashmonocotyledons and dicotyledons

Vocabularycone (p 567)frond (p 567)Survey of the

Plant Kingdom

CHAPTER 21 ASSESSMENT 573

Adapting toLife on Land

To help you review plant adaptations to land use theOrganizational Study Fold on page 559

STUDY GUIDESTUDY GUIDE

(tl)Matt Meadows (bl)David WrobelVisuals Unlimited (br)James H RobinsonEarth Scenes

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0564-0575 C21S2 BDOL-829900 8604 949 AM Page 573

Review the Chapter 21 vocabulary words listed inthe Study Guide on page 573 Match the wordswith the definitions below

1 plants in which the transport of water andother substances is mainly by osmosis anddiffusion from cell to cell

2 the organ that anchors a plant and absorbsmost of the water and minerals used by aplant

3 for plants such as pines and spruces it is theorgan that contains reproductive structures

4 the plant organ that is usually the site ofphotosynthesis

5 a group of tubelike elongated cells throughwhich water and other materials are trans-ported throughout a plant

6 Which of these traits is NOT common toplants and green algaeA reproduce by fissionB contain cellulose in cell wallsC store food as starchD contain the same kind of chlorophyll

7 Vascular tissues are found in ________A bacteria C fernsB algae D hornworts

8 Which of the following characteristics isNOT found in plantsA eukaryotic cells C prokaryotic cellsB cellulose cell walls D waxy cuticle

9 The plant organ in the photo to the right is from a plant in division ________A AnthocerophytaB ConiferophytaC LycophytaD Anthophyta

10 Which group of organisms is probably theancestor of land plantsA cyanobacteria C bryophytesB archaebacteria D green algae

11 Seeds enclosed in a fruit is a structural adap-tation of ________A Anthophytes C ConiferophytesB Bryophytes D Pterophytes

12 The fern structure to the right is called a________A rhizomeB rootC gametophyteD frond

13 Open Ended Explain why biologistshypothesize that the first plants to adapt to life on land may have been similar to liverworts

14 Open Ended Anthophytes are found world-wide and include the greatest number ofknown plant species Identify describe andevaluate characteristics of this division thatwere important to its success Explain yourchoices

15 Open Ended Observe the plants in Figure 216 D and E Describe the struc-tural adaptations that contribute to theirlong-term survival in moist environments

16 Concept Map Copy the concept map belowthen complete it the using the followingterms leaves roots stems vascular tissuevascular plant

contains

1

which is found in

2

4

3 5

574 CHAPTER 21 ASSESSMENT(tr)Matt Meadows (bl)Ed ReschkePeter Arnold Inc

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17 You areappointed to a committee at school that is toplan and plant a flower garden What factorsmust be considered when selecting plants for

this garden Visit toresearch plants and plan the garden Sketch a plan and list your plant selections Explainwhy each plant was chosen

REAL WORLD BIOCHALLENGE

Constructed ResponseGrid InRecord your answers or fill in the bubbles on your answer document using the correct place value

23 Grid In The sporophyte of corn has 20 chromosomes How many chromosomes would youexpect to find in corn gametes

24 Open Ended Describe the differences between seed and non-seed plants Considering structuraland physiological adaptations of these two plant types infer why seed plants are found in morediverse environments than non-seed plants

Seed plants

Conifers

Gnetophytes

Amborella

Water liliesMagnolias Modern

monocotsModerndicots

Flowering plants

CHAPTER 21 ASSESSMENT 575

Multiple ChoiceStudy the cladogram below and answer questions18ndash20

18 The cladogram shows the evolution of someflowering plants According to the clado-gram modern monocots developed________ AmborellaA at the same time as C afterB before D none of these

19 Amborella is most closely related to________A modern monocots C water liliesB modern dicots D magnolias

20 Which of the following plant types evolvedbefore AmborellaA gnetophytes C magnoliasB modern dicots D water lilies

Use the diagram below to answer questions 21and 22

21 The sporophyte produces spores by theprocess of ________A mitosis C fissionB meiosis D fertilization

22 Which of the following would NOT have ahaploid or n number of chromosomesA gametophyte C sporophyteB spore D gamete

GAMETOPHYTE (n)Spores (n)

Meiosis

SPOROPHYTE (2n) Mitosis andcell division

Fertilization

Femalegamete (n)

Malegamete (n)

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