Chapter 24: Reproduction in Plants Computer Test Bank Essarily Those of the Hybrid

Chapter 24 Organizer Reproduction in Plants

Refer to pages 4T-5T of the Teacher Guide for an explanation of the National Science Education Standards correlations. Teacher Classroom Resources Activities/FeaturesObjectivesSection MastersSection TransparenciesReproducible

Reinforcement and Study Guide, pp. 105-106 L2 Section Focus Transparency 58 L1 ELL Section 24.1 1. Review the steps of alternation of MiniLab 24-1: Growing Plants Asexually, Section 24.1 generation. p. 654 Concept Mapping, p. 24 L3 ELL Basic Concepts Transparencies 38, 39, 40 L2 Life Cycles of Mosses, 2. Describe the life cycles of mosses, Problem-Solving Lab 24-1, p. 659 Life Cycles of BioLab and MiniLab Worksheets, p. 109 L2 ELL Ferns, and Conifers ferns, and conifers. BioTechnology: Hybrid Plants, p. 680 Mosses, Ferns, Content Mastery, pp. 117-118, 120 L1 Reteaching Skills Transparencies 35, 36P L1 National Science Education and Conifers P ELL Standards UCP.1, UCP.2, P UCP.3, UCP.5; A.1, A.2; C.1, P Reinforcement and Study Guide, p. 107 L2 P Section Focus Transparency 59 L1 ELL C.5 (1 session) Section 24.2 P LS Content Mastery, pp. 117, 119-120 L1 Basic Concepts Transparencies 41, 42, 43 L2P LS P Flowers and Inside Story Poster ELL P LSELL Flowering Section 24.2 3. Identify the structures of a flower. Problem-Solving Lab 24-2, p. 663 LS LS Reteaching Skills Transparency 37 L1 P ELL 4. Examine the influence of photo- Inside Story: Parts of a Flower, p. 665 LS Flowers and Flowering periodism on flowering. Investigate BioLab: Examining the P PLS Reinforcement and StudyP Guide, p. 108 L2 SectionP Focus Transparency 60 LSL1 ELL National Science Education Structure of a Flower, p. 678 Section 24.3 LS Critical Thinking/Problem Solving, p. 24 P P Standards UCP.1, UCP.2, L3 LS The Life Cycle of BioLab and MiniLab Worksheets, pp. 110-112 L2 P UCP.5; A.1, C.4-6 (1 session, P 1/ block) a Flowering Plant Laboratory Manual, pp. 171-178 L2LS P LS 2 LS P LS Assessment ResourcesContent Mastery, pp. 117, 119-120 L1 AdditionalLS Resources LS 5. Describe the life cycle of a flowering Careers in Biology: Greens Keeper, p. 673 P P LS Section 24.3 Assessment Resources AdditionalP Resources LS plant. MiniLab 24-2: Looking at Germinating LS LS The Life Cycle of a 6. Outline the processes of seed and fruit Seeds, p. 677 Chapter Assessment, pp. 139-144 Spanish Resources ELL P P Flowering Plant formation and seed germination. MindJogger Videoquizzes English/Spanish Audiocassettes ELL National Science Education P LS LS Performance Assessment in the Biology Classroom CooperativeLS Learning in the Science Classroom COOP LEARN Standards UCP.1, UCP.2, Alternate Assessment in the Science Classroom Lesson Plans/Block SchedulingP UCP.3, A.1, A.2; C.1, C.4-6; LS E.1, E.2; F.3, F.6; G1-3 Computer Test Bank P LS P (2 sessions, 1 block) BDOL Interactive CD-ROM, Chapter 24 quiz LS LS LS LS LS Need Materials? Contact Carolina Biological Supply Company at 1-800-334-5551 KeyKey toto TeachingTeaching StrategiesStrategies or at http://www.carolina.com L1 Level 1 activities should be appropriate Teacher’s MATERIALS LIST for students with learning difficulties. Corner L2 Level 2 activities should be within the The following multimedia resources are available from Glencoe. BioLab Alternative Lab ability range of all students. Products Available From Glencoe p. 678 microscope, microscope slide p. 674 canned kidney beans, paper L3 Level 3 activities are designed for above- Biology: The Dynamics of Life To order the following products, call Glencoe (2), coverslips (2), dropper, water, sin- cup, water, dried kidney beans, wax average students. CD-ROM ELL at 1-800-334-7344: gle-edged razor blade, colored pencils paper, labels, tetrazolium solution, ELL ELL activities should be within the ability Animation: Life Cycle of a Moss CD-ROM (red, green, and blue), hand lens, dropper bottle range of English Language Learners. Video: Fern Development NGS PictureShow: What It Means to Be Green flower (complete) COOP LEARN Cooperative Learning activities Animation:P Life Cycle of a Pine Quick Demos P Curriculum Kit P are designed for small group work. Exploration: Angiosperm MiniLabs p. 657 photomicrographs of gameto- P GeoKit: Plants P P These strategies represent student prod- Video: Blooming Flowers p. 654 potato, garlic clove, carrot, test phytes, metric ruler Transparency Set ucts that can be placed into a best-work Videodisc Program tube, petri dish, beaker, toothpicks, p. 662 flower (rose or daffodil) P NGS PicturePack: What It Means to Be Green portfolio. Double Fertilization water, paper, pencil p. 668 peanut Videodisc LS LS These strategies are useful in a block Fruit Formation p. 677 microscope, corn kernels and p. 672 tomato, peach LS STV: Plants LS LS scheduling format. Seed Dispersal bean seeds (germinating and ungermi- LS Germination nated), paper towels, plastic zipper LS bags, single-edged razor blade

652A 652B ChapterChapter 2424 ChapterChapter SECTION PREVIEW Section Objectives Section 24.1 Review the steps of alternation of genera- 24.1 Life Cycles of Mosses, tion. ETTING TARTED EMO Reproduction in Plants GETTING STARTED DEMO 24 Describe the life cycles Prepare Ferns, and Conifers of mosses, ferns, and Show students pictures of conifers. Key Concepts reproductive structures of Vocabulary Alternation of generations is re- mosses, ferns, and conifers. What You’ll Learn ou may have seen the fine yellow dust vegetative reproduction P that covers everything when pine trees protonema viewed and the life cycles of mosses, Have students discuss ways You will compare and con- release their pollen. As annoying as megaspore ferns, and conifers are presented. trast the life cycles of mosses, Y microspore they are similar. ferns, and conifers. this pollen may seem, it has a valuable func- micropyle You will sequence the life tion. It is an important stage in the life cycle Planning LS cycle of a flowering plant. of pine trees. Other plants have even more Theme Development You will describe the charac- Purchase garlic, carrots, and teristics of flowers, seeds, and dramatic stages of their life cycles, such as potatoes for MiniLab 24-1. Unity within diversity is ex- fruits. exploding moss capsules and fern sporangia. Locate pictures of moss, fern, plored in this chapter as the dif- and conifer reproductive struc- Why It’s Important ferent reproductive strategies of Male pine cone tures for Getting Started Demo. major plant divisions are present- Plants are essential to Earth’s releasing pollen biosphere. The fruits and seeds Locate pictures of moss, fern, ed. The theme of systems and produced by flowering plants and conifer gametophytes for interactions is stressed in the are a major food source for the Quick Demo. study of the life cycles of various humans and animals, and critical plants. Evolution is a theme that for the survival of many species. occurs throughout the chapter, Alternation of mature sporophyte allows the life especially as it relates to the GETTING STARTED cycle to begin again. Figure 24.1 1 Focus coevolution of pollinators and Generations illustrates alternation of generations. Looking at Flowers Bellringer flowers. Look closely at two different As you learned earlier, plants go flowers. How are they similar? through an alternation of generations Before presenting the lesson, How are they different? during their life cycles. Remember Figure 24.1 display Section Focus Trans- that the two phases of the plant life All plants exhibit an alternation of generations. The gametophyte (n) stage produces gametes. parency 58 on the overhead pro- To find out cycle are the gametophyte stage and jector and have students answer If time does not permit teach- more about The sporophyte (2n) produces spores. the sporophyte stage. the accompanying questions. L1 ing the entire chapter, use the plants, visit the Glencoe Science The cells of the sporophyte are all ELL BioDigest at the end of the Web Site. www.glencoe.com/sec/science diploid. Certain cells of the sporo- unit as an overview. Male phyte undergo meiosis and produce gamete (n) haploid spores. These spores grow, Spores (n) Female by mitotic division, into the gameto- gamete (n) P Transparency 58 Fern Life Cycle SECTION FOCUS Use with Chapter 24, Section 24.1 phyte. The multicellular gameto- GAMETOPHYTE (n) phyte that is formed is composed of haploid cells. Some cells of the game- Animals often play an Meiosis Fertilization important role in polli- tophyte will differentiate and form LS P nating flowering plants. haploid gametes. The female gamete Insects, including bees, is the egg, and the male gamete is the SPOROPHYTE (2n) transport pollen from sperm. When a sperm fertilizes an New sporophyte flower to flower. Most Gametophyte nonflowering plants, egg, a diploid zygote is formed. This Mitosis Sporophyte LS such as mosses, rely on zygote divides by mitosis, producing wind or water for the dis- a tiny sporophyte or embryo. The persal of spores. development of the embryo into a Fern Moss

1 Which generation is dominant in the life cycle of this fern?

2 How does this compare with the life cycle of mosses? 652 REPRODUCTION IN PLANTS 653 Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Assessment Planner BIOLOGY: The Dynamics of Life SECTION FOCUS TRANSPARENCIES Look for the following logos for strategies that emphasize different learning modalities. Assessment Planner Kinesthetic Meeting Individual Portfolio, p. 670; Tech Prep, p. 672; Portfolio Assessment Alternative Lab, TWE, pp. 674-675 Multiple Needs, p. 662; Building a Model, Enrichment, p. 673 Assessment, TWE, p. 657 BioLab, SE, pp. 678-679 Learning p. 669; Tech Prep, p. 675; Portfolio, Intrapersonal Enrichment, Portfolio, TWE, pp. 656, 662, 670, 676 Knowledge Assessment ResourceResource p. 676 p. 664; Project, p. 664 Alternative Lab, TWE, p. 675 Section Assessment, SE, pp. 660, 666, 677 ManagerManager Styles Visual-Spatial Biology Journal, Linguistic Meeting Individual Performance Assessment Assessment, TWE, p. 669 p. 657; Meeting Individual Needs, Needs, p. 655; Portfolio, pp. 656, MiniLab, SE, pp. 654, 677 BioLab, TWE, p. 679 Section Focus Transparency 58 pp. 658, 665, 672; Reteach, p. 660; 662; Biology Journal, pp. 663, 668; MiniLab, TWE, pp. 654, 676 Chapter Assessment, SE, pp. 681-683 and Master L1 ELL Display, p. 664; Discussion, p. 666; Extension, p. 666 Problem-Solving Lab, TWE, pp. 659, 663 Skill Assessment Quick Demo, p. 668; Reinforcement, Logical-Mathematical Quick Assessment, TWE, pp. 666, 676, 677 Assessment, TWE, p. 662 652 p. 668; Microscope Activity, p. 668; Demo, p. 657 653 P

LS P

LS Revealing Misconceptions The basic pattern of this life cycle even seen a female gametophyte of a form a structure called a protonema. ing a diploid zygote. The zygote 2 Teach is the same for all plants. However, flowering plant. Botanists usually refer The protonema (proht uh NEE muh) divides by mitosis to form a new Students learned in previous there are many variations on this pat- to the bigger, more obvious plant as is a small green filament of cells that sporophyte. The sporophyte is a stalk chapters that the process of meio- tern within the plant kingdom. For the dominant generation. The domi- develops into either a male or a with a capsule at the top. It grows out sis forms gamete cells. This is true MiniLab 24-1 P instance, recall that in mosses the nant generation lives longer and can female gametophyte. In some of the archegonium and remains for animals. However, in plants, gametophyte is bigger than the sporo- survive independently of the other mosses, the gametophyte can pro- attached to the gametophyte. The spores are produced directly Purpose phyte. In others, such as flowering generation. In most plant species the duce both kinds of reproductive sporophyte receives much of its nutri- though meiosis and then gametes Students will use several different plants, the gametophyte is tiny, even sporophyte is the dominant plant. structures. Remember that the tion from the gametophyte. Meiotic are formed through mitosis of plant parts to demonstrate the microscopic. Most people have never archegonium is the female reproduc- division within the capsule produces these haploid cells. LS Asexual reproduction ability of plants to form new tive structure in which eggs are pro- haploid spores. Why the difference between plants via asexual reproduction. Most plants can also reproduce by duced and that sperm are produced The capsule ripens, bursts, and plants and animals? Actually, a process called vegetative reproduc- in the antheridium. releases the spores, which can be car- Process Skills MiniLab 24-1 Experimenting there is no difference. Plants just tion. Vegetative reproduction is The motile sperm are released from ried great distances by air currents. If have an added stage or step that experiment, analyze information, asexual reproduction in plants where the antheridium and swim through a the spore lands in a favorable envi- results from alternation of gener- collect data, compare and con- Growing Plants Asexually Plants are capable of reproduc- a new plant is produced from an continuous film of rainwater or dew to ronment, it germinates, completing ations. In this process, meiosis trast, draw a conclusion ing asexually. Reproductive cells such as egg or sperm are not existing vegetative structure. For the archegonium. The sperm fertilizes the life cycle. Review the moss life needed in asexual reproduction. Plants are able to use structures instance, liverworts produce asexual the egg inside the archegonium, form- cycle as you examine Figure 24.3. still forms haploid spore cells— Teaching Strategies such as roots, stems, and even leaves to produce new offspring. the gametophyte generation— Have students work in small structures called gemmae that fall Garlic clove Potato with eye off and develop into new plants, that remain haploid. The gameto- groups to conserve materials. (storage leaves) (stem & buds) Figure 24.3 phyte is equivalent to one large Figure 24.2. The new plants have Make sure that the original Toothpick The leafy green gametophyte of a the same genetic make-up as the Developing male or female animal gamete. Water moss produces gametes that fuse root end (blunt end) of the garlic original plant, as if they were Mitosis sporophyte clove is immersed in water. One to form a zygote. The zygote Test tube cloned. You can learn more about develops into the sporophyte. Visual Learning Water garlic head should supply enough Carrot asexual reproduction in the MiniLab The sporophyte produces (root) Beaker Figure 24.3 To reinforce the cloves for an entire class. shown here. spores. The spores germi- Sporophyte (2n) Both garlic and potato may be Water nate and grow into a Zygote (2n) concept of diploid versus haploid, suspended over water using gametophyte, com- ask students to assign a specific pleting the life cycle toothpicks as bracing. Small jars A B C Life Cycle of Mosses chromosome number to each A B C of a moss. Gametophyte (n) (baby food jars, plastic bathroom Mosses belong to one of the few stage in Figure 24.3. Explain that cups) may be used in place of Procedure plant divisions in which the gameto- the diploid number for this beakers or test tubes. ! Prepare three different plant parts for study using diagrams phyte plant is the dominant genera- Sperm species is 18. L2 A, B, and C as a guide. tion. A haploid spore germinates to SPOROPHYTE Make sure that students iden- Egg @ Observe any changes that occur to your plants over the GENERATION Capsule tify their plants by placing labels next two weeks. Fertilization Figure 24.2 2n on the jars and/or dishes. # Design a data table that will provide enough room for Small cups filled with tiny gemmae have Tell students to replace any Antheridium Archegonium Meiosis diagrams of your observations, the number of days since formed on the thallus of this liverwort. lost water from the containers. the start of the experiment should be included. GAMETOPHYTE Open capsule CD-ROM Some potatoes are chemically $ Make your initial diagrams of the plant parts today and GENERATION Biology:P The Dynamics treated to inhibit growth of eyes. label these diagrams as “Day 1.” n of Life This may account for either slow % Observations should be made every three days. Replace any lost water as needed. Animation: Life Cycle of a Moss or no new growth appearing Analysis Disc 3 within the two-week period. Germinating 1. What experimental evidence do you have that: spores VIDEODISCLS Expected Results a. plants use a variety of structures for asexual reproduc- Biology: The Dynamics All plant tissues will produce new tion? of Life growth. The garlic clove will b. asexual reproduction is a rapid process? c. asexual reproduction requires only one parent? Life Cycle of a Moss (Ch. 17) show new root and stem/leaf 2. Describe several advantages of asexual reproduction in Disc 1, Side 2, 1 min. 3 sec. growth. The carrot will show new Male Female plants. gametophyte gametophyte Protonema leaves. The potato will show new (n) (n) Rhizoids !8rÜ" stems and leaves.

Analysis 654 REPRODUCTION IN PLANTS 24.1 LIFE CYCLE OF MOSSES, FERNS, AND CONIFERS 655 1. a. The experimental proce- dure demonstrates that dif MEETING INDIVIDUAL NEEDS ferent plant parts can gen- 2. Student answers may vary; they may what conditions stimulate the appearance of Resource Manager erate new growth. include faster growth and that all off- new plants along the leaf’s edge. Use the English Language Learners/ b.The appearance of new spring are identical to parent. Performance Task Assessment List for Carry- growth occurred within ing Out a Strategy and Collecting Data in Learning Disabled BioLab and MiniLab Worksheets, Linguistic Have students review p. 109 L2 several days. Assessment PASC, p. 25. L3 c. Only one plant was used terms associated with alternation Basic Concepts Transparency 38 and for each experimental setup. Performance Provide students with a of generations by reinforcing the correla- Master L2 ELL plant called Kalanchoe (available in most gar- tion between the name of each generation Reteaching Skills Transparency 35 den shops). Have them use leaves from the and its function. For example, sporophytes and Master L1 ELL plant to grow new plants asexually. Have stu- P P form spores, while gametophytes form P 654 dents conduct an experiment to determine gametes. L1 ELL 655 P P LS P LS P LS LS LS LS P LS P LS LS Revealing Misconceptions Figure 24.4 Figure 24.5 Quick Demo Students frequently think the sori Fern sporophytes are easily seen by a hiker In the life cycle of a present on the underside of fern walking through a forest. However, only the fern, the sporophyte Logical- very observant person would be able to find fronds are some kind of insect generation becomes Archegonia a fern gametophyte. independent of the Spores (n) Mathematical infestation. Explain that these gametophyte. Give students pictures of structures produce spores. moss, fern, and conifer game- Antheridia tophytes that have the magni- Chalkboard Activity fication noted on the photo. Have students write a simple Egg Have them calculate the size of moss life cycle sequence on the each gametophyte. The size of Meiosis board. Help them get started by the drawing (in millimeters) showing them what the cycle may Rhizoids divided by the magnification look like by providing them with Archegonium equals the size of the original this sample: sporophyte ⇒ spores B The clusters of sporangia on the gametophyte (in millimeters). by meiosis ⇒ protonema ⇒ etc. underside of a fern frond are Students will then be able to called sori. Each sporangium con- Antheridium P GAMETOPHYTE compare the size of the game- tains spores that are released, tophytes. sometimes in dramatic fashion. GENERATION L3 Sporangium 2n Sperm Meiosis Fertilization LS Chalkboard Activity CD-ROM Pinna Write the following terms on the Biology: The Dynamics SPOROPHYTE chalkboard: spore,P zygote, egg, of Life GENERATION sporophyte, and sperm. Have Video: Fern Development 2n A Most fern sporophytes students identify whether each Disc 3 C The heart-shaped grow 25 cm or taller. fern gametophyte structure is haploid or diploid. VIDEODISC Zygote is usually less than L2 LS a centimeter across. Sporophytes Biology: The Dynamics (2n) of Life Sorus Fern Development (Ch. 18) Assessment Disc 1, Side 2, 17 sec. sion within the sporangia produces Some mosses also reproduce asex- Fronds Portfolio Have students ually by vegetative reproduction. the spores. When environmental prepare a biological key that will !8|á" They can break up into pieces when conditions are right, the sporangia Rhizome Mitosis enable others to identify mosses, the plant is dry and brittle. With the burst to release haploid spores. ferns,P and conifers based on fea- arrival of wetter conditions, these A spore germinates to form a tures of the plant life cycle, pieces each become a whole plant. heart-shaped gametophyte called a Roots prothallus, as shown in Figure 24.5. including reproductive parts. L2 ResourceResource The prothallus produces both ManagerManager Life Cycle of Ferns archegonia and antheridia on its sur- LS Unlike mosses, the dominant stage face. The flagellated sperm released Concept Mapping, p. 24 L3 of the fern life cycle is the sporo- by the antheridium swim through a ELL phyte plant. The fern sporophytes film of water to the archegonium once the sporophyte produces its fern plants will develop from them by Basic Concepts Transparency include the familiar fronds you see in where the egg is fertilized. The green fronds, it can carry on photo- vegetative reproduction. New spo- 39 and Master L2 ELL Figure 24.4. The fronds of the fern diploid zygote that is the product of synthesis and survive on its own. The rangia develop on the pinnae of the P P grow from the rhizome, which is the this fertilization develops into the prothallus disintegrates as the sporo- fronds, spores will be released, and P underground stem. On the underside sporophyte. Initially, this developing phyte matures, producing a strong the cycle will begin again. The life P of some fronds are the sori, which are sporophyte depends upon the game- rhizome that can support the fronds. cycle of the fern is summarized in clusters of sporangia. Meiotic divi- tophyte for its nutrition. However, If pieces of rhizome break away, new Figure 24.5. LS LS LS 656 REPRODUCTION IN PLANTS 24.1 LIFE CYCLE OF MOSSES, FERNS, AND CONIFERS 657 P LS PortfolioPortfolio BIOLOGYIOLOGY JOURNAL LS Chemistry in Biology Fern Life Cycle Linguistic Have students do research Visual-Spatial Have students dia- and prepare a report about the role gram the stages of the fern life cycle P of chemotaxis in moss and fern reproduc- in their journals for review. Encourage tion. L3 P students to divide the diagram so that all sporophytes are on one side and all gametophytes are on the other. Have P LS them label the diagram Sporophyte stages, 656 LS Gametophyte stages. L1 ELL 657 P LS P LS LS P

LS Using Scientific Terms The Life Cycle the female gametophyte. The female female cone. The pollen grain Problem-Solving Lab 24-1 Challenge students to use their gametophyte consists of hundreds of adheres to a sticky drop of fluid that Problem-Solving Lab 24-1 Making and P knowledge of the prefixes micro- of Conifers cells but is still dependent on the covers the opening of the ovule. As Using Tables and mega- to describe the relative The dominant stage in conifers is sporophyte for protection and nutri- the fluid evaporates, the pollen grain Purpose What traits do mosses, ferns, and conifers share? sizes of microspores and megas- the sporophyte generation. One of tion. Within the female gametophyte is drawn closer to an opening of the Sometimes it helps to organize information in a table. The Students will identify and catego- pores. Microspores are smaller than the more familiar conifer sporo- are two or more archegonia, each ovule called the micropyle (Mi kruh advantage of a table is that it summarizes traits and shows rize the similaritiesLS and differ- megaspores. Have students specu- phytes is shown in Figure 24.6. The containing an egg. The male cones pile). Although pollination has similarities and differences in a simple format. ences among mosses, ferns, and WORD Origin adult conifer produces male and have sporangia that undergo meiosis occurred, fertilization will not take late why it is important for Analysis pines by completing a chart. micropyle female cones on separate branches of to produce male spores called place for at least a year. The pollen microspores to be small. They Copy the following data table. Complete the table using From the Greek develop into pollen grains that must the tree. The cones contain spore- microspores. Each microspore will grain and the female gametophyte “yes” and “no” answers. Process Skills words mikros, producing structures, or sporangia, develop into a male gametophyte, or will mature during this time. be light enough to be dispersed by meaning “small,” compare and contrast, think criti- on their scales. The female cones, pollen grain. Each pollen grain, with As the pollen grain matures, it pro- Data Table wind. L2 ELL and pyle, meaning cally, analyze information, apply “gate.” The micro- which are larger than the male cones, its hard, water-resistant outer cover- duces a pollen tube that grows through TraitMoss Fern Conifer concepts, predict pyle is the small develop two ovules on the upper sur- ing, is a male gametophyte. Look at the micropyle and into the ovule. A Has alteration of generations Visual Learning opening at one end face of each cone scale. Each ovule Figure 24.6 to see examples of male sperm cell from the male gametophyte Film of water needed for fertilization Teaching Strategies Have studentsP identify the of the embryo sac. contains a sporangium with a diploid and female conifer gametophytes. is transported by the pollen tube to Dominant gametophyte You may wish to photocopy haploid structures in Figure cell that produces, by meiosis, four In conifers, pollination is the the egg, where fertilization occurs. the chart and pass out the copies 24.8. microspores, megaspores, megaspores. A megaspore is a transfer of the pollen grain from the The zygote, which is nourished by Dominant sporophyte to your students. pollen grains, egg female spore that eventually becomes male cone to the female cone. the female gametophyte, develops Sporophyte is photosynthetic P Review the meaning of any Have students identify the the female gametophyte. One of the Pollination occurs when a wind- inside the ovule into an embryo with Produces seeds LS terms used in the chart that may structures that make up the four megaspores will survive and borne pollen grain falls near the several cotyledons. The cotyledons Produces sperm be unfamiliar to students. sporophyte and gametophyte grow by mitotic cell divisions into opening in one of the ovules of the nourish the developing sporophyte. Produces pollen grains The ovule provides the seed coat as Allow students to work in generations. Cones and embryo Produces eggs small groups to complete the are LSsporophytes; all other struc- the mature seed is produced. Figure 24.6 The seed is released when the chart. Make sure they use their tures are gametophytes. In conifers, the sporo- A This pine sporophyte Thinking Critically A female cone opens. When conditions phyte is immense can grow more than 1. Which two plant groups share the most characteristics? text as a reference to aid in verifi- compared with the 25 meters tall. are favorable, the seed germinates Which two share the fewest? cation of answers. microscopic gameto- into a new, young sporophyte—a 2. While on a woodland trail, would you easily observe: Review student answers on the phytes. pine tree seedling, Figure 24.7. See a. A pine gametophyte? Sporophyte? Explain. chart prior to them answering the if you can identify the stages of the b. A fern gametophyte? Sporophyte? Explain. questions. life cycle in Figure 24.8. Use the 3. Using information from your table, summarize the repro- CD-ROM B The female Answers going down each column gametophyte Problem-Solving Lab on this page to ductive similarities and differences among mosses, ferns, Biology: The Dynamics and conifers. of the table. in this pine further explore the life cycles of Moss: yes, yes, yes, no, yes, no, yes, of Life ovule is less mosses, ferns, and conifers. Animation: Life Cycle of a Pine than 0.01 mm no, yes Disc 3 long. Fern: yes, yes, no, yes, yes, no, yes, no, yes VIDEODISC Figure 24.7 Conifer: yes, no, no, yes, yes, yes, yes, Biology: The Dynamics Conifer seeds germinate yes, yes of Life into new, young sporo- Life Cycle of a Pine (Ch. 20) phytes such as the pine Thinking Critically Disc 1, Side 2, 1 min. 37 sec. tree seedling shown here. C A pollen grain 1. Mosses and ferns share the is so small it !9,Ä" can be carried most characteristics. Mosses by the wind. and conifers share the least. 2. Both ferns and mosses require a film of water for fertilization. Therefore, both would most likely be found growing in damp or moist environments. 658 REPRODUCTION IN PLANTS 659 3. All three have alternation of generations and produce MEETING INDIVIDUAL NEEDS Assessment sperm and eggs. Both mosses Resource Manager Performance Have students attempt and ferns need water for fer- Learning Disabled to grow fern gametophytes from spores. tilization; conifers do not. Reinforcement and Study Guide, Visual-Spatial Prepare individual Instructions and spores are available through Mosses have a dominant pp. 105-106 cards with a drawing on each show- L2 biological supply houses. Use the Perform- gametophyte; ferns and Content Mastery, p. 118 ing one single stage of the life cycle of the L1 ance Task Assessment List for Carrying conifers have a dominant Basic Concepts Transparency 40 and pine. Provide a packet of cards to students Out a Strategy and Collecting Data in PASC, sporophyte. Conifers produce Master L2 ELL pollen grains and seeds; who are learning disabled. Have students p. 25. L3 ELL arrange the cards in proper sequence to Reteaching Skills Transparency 36 Mosses and ferns do not. P illustrate the complete life cycle for a typi- and Master L1 ELL 658 cal pine. L1 ELL P 659 P P LS P P P P P LS LS LS LS LS LS P LS P

LS LS Figure 24.8 SECTION PREVIEW The life cycle of a conifer Microspore mother cells 3 Assess Male cone Section 24.2 includes the production Section Objectives Check for Understanding of two types of spores by Identify the structures Ask students to explain the rela- the sporophyte. These of a flower. spores develop 24.2 Flowers and Flowering Examine the influence tionships of the following word of photoperiodism on Prepare into the male Female cone Ovule Microspores pairs. L2 ELL and female flowering Megaspores a. gametophyte—sporophyte gametophytes. Vocabulary Key Concepts b. antheridium—sperm petals Flower anatomy and modifica- Male ow would you choose flowers sepals c. archegonium—eggP gametophyte for a garden or a bouquet? stamen tions are discussed in this section. d. megaspore—microspore Perhaps you would start with anther The role of photoperiodism in H pistil anthophyte reproduction is ex- Pollen fragrant roses, jasmine, or gardenias. ovary plained. Reteach GAMETOPHYTE grain You might add color with tall spikes of photoperiodism P short-day plant Visual-Spatial Divide the Young Adult GENERATION gladioli, cushions of marigolds, bright LS seedling sporophyte long-day plant class into small groups and n daisies, or irises. Grasses would con- day-neutral plant Planning assign different groups the task of Two archegonia tribute a graceful shape, though their n Locate flowers for the Quick with egg cells flowers may be so small they are easy making flowcharts of the life SPOROPHYTE Meiosis Demo. cyclesLS of mosses, ferns, and GENERATION Female to overlook. All of these flowers n Purchase flowers for the Bio- conifers. Have them put their 2n gametophyte are beautiful to look at and Lab. flowcharts on the chalkboard or some have delicate scents as n Locate flower model for Meet- poster board for class discussion. well. In what other ways are ing Individual Needs. Fertilization L2 COOP LEARN Seed all of these flowers alike? n Collect pictures of different flowers for the CLOSE activity. ExtensionP Have students research which animals use the cones of conifers Flowers display a variety 1 Focus as a foodLS source. L3 of shapes and colors. P Seed coat Bellringer Egg Assessment Cotyledons Before presenting the lesson, Knowledge Have students Embryo display Section Focus Trans- Pollen grain explain the role of water in moss, parency 59 on the overhead pro- P fern,LS and conifer reproduction. Stored Sperm nucleus The structure of a flower jector and have students answer food What Is a Flower? L2 Germinating pollen Even though there is an almost the accompanying questions. L1 One egg is fertilized The process of sexual reproduction limitless variation in flower shapes ELL LS in flowering plants takes place in the and colors, all flowers share a simple, DECODE flower, which is a complex structure basic structure. A flower is usually Gl /M G Hill Section Assessment 4 Close made up of several parts. Some parts made up of four kinds of organs: P Transparency 59 Seed Dispersal SECTION FOCUS Use with Chapter 24, Biology Journal Understanding Main Ideas Thinking Critically of the flower are directly involved in sepals, petals, stamens, and pistils. Section 24.2 1. Explain how vegetative reproduction can pro- 5. Why is the term alternation of generations fertilization and seed production. The flower parts you are probably HaveP students compare the game- duce a new plant. Provide an example. appropriate to describe the life cycle of a plant? Other floral parts have functions in most familiar with are the petals. A. B. 2. In what way is the sporophyte generation of a tophyte and sporophyte gener- SKILL REVIEWEVIEW pollination. There are probably as Petals are leaflike, usually colorful moss dependent on the gametophyte generation? LS P ations of mosses, ferns, and coni- 3. Describe the formation of the male gametophyte 6. Sequencing Sequence the events in the life of a many different shapes, sizes, colors, structures arranged in a circle around fers. L2 in a conifer. fern, beginning with the prothallus. For more and configurations of flower parts as the top of a flower stem. Sepals are LS 4. What are two differences between the life cycle help, refer to Organizing Information in the Skill there are species of flowering plants. also leaflike, usually green, and encir- of a fern and that of a conifer? Handbook. In fact, features of the flower are cle the flower stem beneath the C. D. often used in plant identification. petals. LS

660 REPRODUCTION IN PLANTS 24.2 FLOWERS AND FLOWERING 661

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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 1 How does the structure of each seed make it suitable Internet Address Book for its method of dispersal? Section Assessment 2 Why is seed dispersal important? 1. Vegetative reproduction is when a new 3. The sporangia within the male pinecone dependent upon the gametophyte. Note Internet addresses that you find useful in the space BIOLOGY: The Dynamics of Life SECTION FOCUS TRANSPARENCIES plantLS is produced from an existing veg- produce microspores. The microspores 5. The sporophyte generation alternates below for quick reference. etative structure. An example would be develop into the male gametophyte or with the gametophyte generation in the growth of liverworts from the gem- pollen grain. the life cycle. mae that fall off a parent plant. 4. The gametophyte is dominant in mosses, 6. Prothallus ⇒ forms egg and sperm ⇒ 2. The sporophyte depends upon the whereas the sporophyte is dominant in fertilization of egg by sperm forms a gametophyte for support and most of ferns. In ferns, the sporophyte can exist young sporophyte ⇒ sporophyte pro- its nutrition. independently of the gametophyte but duces spores ⇒ spores germinate to 660 in mosses the sporophyte remains each form a prothallus. 661 Inside the circle of petals are the floral structure and practice your lab Plants such as sweet corn that are Problem-Solving Lab 24-2 2 Teach stamens. A stamen is the male repro- skills in the BioLab at the end of this adapted for pollination by wind Interpreting Scientific Problem-Solving Lab 24-2 Illustrations P ductive structure of a flower. At the chapter. rather than animal pollinators have tip of the stamen is the anther. The no petals. Figure 24.9 shows some Purpose Quick Demo Modifications in flower structure How do flowers differ? There is considerable variation in anther produces pollen that contains examples of the variety in flower flower shape. This variation occurs when certain flower parts Students will study and interpret Display a flower such as a rose sperm. A flower that has all four organs— forms. Study the structure of a typi- are fused together, parts are rearranged, or when parts may diagrams of flower cross sections. cal flower in the Inside Story. You can be totally missing. However, with all the variation seen in LS or daffodil. Elicit the function At the center of the flower, sepals, petals, stamens, and pistils—is attached to the top of the flower called a complete flower. The morn- explore flower adaptations further in flower shape, there are certain general patterns. Almost all Process Skills of the flower. It is a reproduc- stem, lie one or more pistils. The ing glory and tiger lily shown in the Problem-Solving Lab shown here. dicot plants will have flower parts that are in fours or fives or multiples of these numbers. For example, a plant having think critically, compare and con- tive structure. Ask if grass also There is an amazing amount of pistil is the female structure of the Figure 24.9 are examples of com- eight or ten petals, sepals, and stamens would be a dicot. trast, interpret scientific illustra- reproduces through flowers. flower. The bottom portion of the plete flowers. A flower that lacks one diversity in the structures of antho- Most students will answer no. Almost all monocot plants have flower parts in threes or mul- tions pistil enlarges to form the ovary, a or more organs is called an incom- phyte flowers, seeds, fruits, and vege- tiples of three. Explain that grass is a flower- structure with one or more ovules, plete flower. For example, squash tative structures. Anthophytes are Figure 24.9 Teaching Strategies ing plant but is often not rec- each containing one egg. As you read plants have separate male and female divided into different divisions and Analysis The diversity of Diagram A shows a flower with all of its parts labeled. Review the basic anatomy of ognized as such because its in the previous section, the female flowers. The male flowers have sta- classes based on these differences. P flower forms is evi- Imagine that the flower has been cut along the dashed line. a flower before this activity. flowers do not have showy gametophyte develops inside the mens but no pistils; the female flow- The relationships among the differ- dence of the success Diagram B is a diagrammatic cross-section view seen when Make sure that students petals. of flowering plants. ovule. You can learn more about ers bear pistils but no stamens. ent classes and divisions of antho- looking down onto the cut edge of the bottom half. Diagram phytes are shown in Figure 24.10. B is shown a little larger than A so that any details can be understand the differences See if you can recognize any of the more clearly seen. The flower is from a dicot plant because between complete and incom- A The spotted petals of LS different divisions of plants. there are five sepals, petals, and stamens. plete flowers. The BioLab at the the tiger lily curl away Review the characteristics of INVESTIGATE end of the chapter from the reproductive A B structures at the cen- Pistil monocots and dicots. can be used at this ter of the flower. Photoperiodism Provide examples of flowers Stamen point in the lesson. The relative length of day and having floral structures in multi- night has a significant effect on the Petal ples of three, four, and five. rate of growth and the timing of Illustrate a “cross-section” cut Sepal Assessment flower production in many species of using a cucumber as an example. Assessment flowering plants. For example, Skill Have students con- chrysanthemums produce flowers Thinking Critically Thinking Critically struct a chart that summarizes only during the fall, when the days 1. Diagrams C, D, and E are diagrammatic cross-section views 1. a. monocot; flower parts in flower structures and the function are getting shorter and the nights of flowers. Determine if diagram: B The male flowers of the walnut threes of each part. Their chart should B longer. A grower who wants to pro- a. C is a monocot or dicot. Explain. tree form long catkins. b. D is a monocot or dicot. Explain. b.dicot; flower parts in four include petals, sepals, pistil, and duce chrysanthemum flowers in the c. E is a monocot or dicot. Explain. or multiples of four stamens. L2 middle of summer drapes black cloth C The petals of the morning 2. Do diagrams A, C, D, and E show flowers that are com- C over the plants to artificially increase c. dicot; flower parts in fours glory are fused together to plete or incomplete? Explain. Note: Complete flowers or multiples of four form a bell shape. the length of night. The response of have sepals, petals, stamens, and pistils whereas incom- flowering plants to the difference in plete flowers lack one or more of these parts. 2. A and C are complete flowers the duration of light and dark periods 3. Which flowers are capable of self-pollination? Explain. as all flower parts are present. in a day is called photoperiodism. 4. Which flowers require cross-pollination? Explain. D and E are incomplete flow- CD-ROM Plant biologists originally thought ers as D is missing sepals and Biology:P The Dynamics that day length controlled flowering. E is missing a pistil. However, they now know that it is the of Life D Thistles bear 3. A, C, and D as they have clusters of tiny, length of the night, or dark period, Exploration: Angiosperm both stamens and pistils. tubular flowers that controls flowering. Plants can be Disc 3 Both male and female flower within a mass placed in three categories depending of spiny bracts. LS on the conditions they require for parts are needed for self- C D E fertilization E The location of corn tassels flower production. Plants are either C D E at the top of the plant aids short-day plants, long-day plants, or 4. E requires cross-pollination in wind pollination. day-neutral plants. as it does not have a pistil.

662 REPRODUCTION IN PLANTS 24.2 FLOWERS AND FLOWERING 663 Assessment Performance Have stu- MEETING INDIVIDUAL NEEDS PortfolioPortfolio BIOLOGYIOLOGY JOURNAL dents make a sketch of dia- Resource Manager grams C through D and label the Visually Impaired Flower Modifications Keeping a Plant Diary flower parts. Have them make Kinesthetic Purchase or borrow a Linguistic Have students collect Linguistic Have students imagine that Reteaching Skills Transparency 37 a cross-section diagram of the large flower model. Allow visually pictures of flowers showing differ- they are a chrysanthemum. It is spring- and Master L1 ELL female flower of E. Use the Per- impaired students to manipulate the ent structural modifications. Next to time and they have just started growing. Basic Concepts Transparency 41 and formance Task Assessment List model as you name and describe the func- each picture have the students write a Ask them to describe what they look like, Master L2 ELL for Scientific Drawing in PASC, tion of each part. Have the student then brief paragraph describing the adaptive explain why they are not forming flowers, Section Focus Transparency 59 and P P p. 55. L2 ELL tell you if the part is male, female, or nei- value of the modification. L2 P and indicate the relative lengths of day and Master L1 ELL P P ther in terms of flower function. L1 night. Have students repeat the process for P 662 ELL each of the other seasons. L1 663 P P LS LS LS LS LS P P P LS P LS P LS LSP LS LS P LS LS P LS LS LS Enrichment Figure 24.10 Intrapersonal Advise stu- There are two classes of antho- IINSIDENSIDE IINSIDENSIDE dents that the light that phytes—monocots and dicots. Within triggers flower production does each class there are many different STORY STORY families, which show a great amount P not have to reach the plant’s of variation in their vegetative and flower buds, but must reach and reproductive structures. Parts of a Flower Purpose be detected by the leaves. Have To describe flower anatomy and students design an experiment to f the four major organs of a flower, only two—the identify the role flower parts play Cocoa stamens and pistils—are fertile structures directly LS prove that it is the leaf that must PLANTS O Sterculiaceae in reproduction. be stimulated by light for the involved in seed development. Sepals and petals support Magnolia and protect the fertile structures and help attract pollina- plant to achieve flowering. Cactus Magnoliaceae Teaching Strategies Chicory Cactaceae tors. The structure of a typical flower is illustrated here by Suggest that it is possible to place Asteraceae Ask students to explain why parts of the plant behind light a phlox flower. stamens and pistils are described Blue phlox barriers while other parts of the Critical Thinking How are different flower shapes as the fertile structures in a same plant are exposed to light. important to a plant’s survival? flower. These structures are L3 Petals involved in the production of egg and 1 Petals These are usually brightly colored Anther sperm. Elicit what role is played Reinforcement by flower organs that are not Oak and often have perfume or nectar at their bases to attract pollinators. In Pollen Explain to students that lily grow- Caraway Fagaceae grains important in fertilization. These Milkweed many flowers, the petal also provides Apiaceae Asclepiadaceae organs attract pollinators or protect ers get their greenhouse plants to a surface for insect pollinators to P Coleus young or immature fertile flower flower early in spring by subject- Lamiaceae rest on while feeding. Petals may ing the plant to artificial lighting be fused to form a tube, or parts. L2 that simulates longer days and shaped in ways that make the Visual Learning shorter nights. Ask students if flower more attractive to pollinators. liliesLS are short-day plants or long- Ask students to use the cap- day plants. long-day tions to explain how the fol- lowing pairs of terms are Display 2 Stigma At the top of the related: (a) sepals and calyx; (b) Palm pistil is this sticky or feathery Stigma petalsP and corolla; (c) stamen Visual-Spatial Using Figure Palmae surface on which pollen and anther; (d) stigma and 24.10 as a guide, have stu- grains land and grow. The Raspberry style is the slender stalk of style; (e) ovary and ovule. L1 dents create a giant fan diagram Rosaceae the pistil that connects the Style on the wall or on a bulletin Dicots stigma to the ovary. The Stamen Critical Thinking Pistil LS board. Ask them to bring in pic- pollen tube grows down the The shape of a flower may tures of monocots and dicots to length of the style to reach Filament Grass promote different pollination add to the display. L2 ELL the ovary. The ovary, which Poaceae Monocots will eventually become the Corolla methods. For example, tubular fruit, contains the ovules. flowers are probably pollinated by Ovary Each ovule, if fertilized, will Sepals animals. become a seed. P Lily Ovule Liliaceae Chalkboard Activity P 4 Stamen The pollen-producing Write the following phrases on CD-ROM 3 Sepals A ring of sepals makes up anther at the tip and a thin fila- the chalkboard: contains chloro- Biology: TheP Dynamics Protists the outermost portion of the flower. Calyx ment that attaches the anther phyll, contains anthocyanin, of Life LS The sepals serve as a protective covering to the flower stem make up the stamen. When the pollen grains where meiosis takes place, con-LS Video: Blooming Flowers for the flower bud, helping to protect it Orchid from insect damage and prevent it from developing inside the anther tains gametophyte, is part of the Orchidaceae Disc 3 drying out. Sepals sometimes are reach maturity, the anther splits sporophyte, contains diploid cells, PRESENT CENOZOICMESOZOIC PALEOZOIC PRECAMBRIAN VIDEODISCLS colored and resemble petals. open to release them. forms spores, forms microspores, Biology: The Dynamics forms megaspores. Ask students of Life 664 REPRODUCTION IN PLANTS 24.2 FLOWERS AND FLOWERING 665 to identify the flower organ or Blooming Flowers (Ch. 21) organs described by each phrase. Disc 1, Side 2, 26 sec. MEETING INDIVIDUAL NEEDS L2 !96Å" PROJECT Resource Manager Are Bees the Best? English Language Learners/ Intrapersonal Members of the Learning Disabled Reinforcement and Study Guide, Brassica genus can be pollinated Visual-Spatial Have students create p. 107 L2 ELL with cotton swabs, paint brushes, and a table with the heads Male, Female, Content Mastery, p. 119 L1 dried bees. Have students design an Neither male nor female. Ask students to P experiment to determine whether or list the following structures beneath the P P appropriate head: stamen, pistil, anther, not bees are the most efficient pollina- P tors. L3 calyx, corolla, ovary, stigma, petal, sepal, 664 pollen, egg, ovule, style. L1 ELL 665 P LS LS LS LS P P P LS

LS LS LS P

LS Figure 24.11 SECTION PREVIEW 3 Assess Photoperiodism refers to a Section 24.3 plant’s sensitivity to the Section Objectives Check for Understanding changing length of night. Describe the life cycle of a flowering plant. Ask students to explain the rela- 24.3 The Life Cycle of a Outline the processes tionships of the following word of seed and fruit Prepare groups. L2 ELL Flowering Plant formation and seed germination. Key Concepts a. stamen—anther Vocabulary b. pistil—stigma—ovary ransferring pollen from anther to The formation of anthophyte polar nuclei gametophytes, pollination, and c. ovary—ovuleP stigma is just one step in the life cycle double fertilization of a flowering plant. How does polli- endosperm double fertilization are presented. T dormancy Seed and fruit development are Reteach nation lead to the development of seeds encased germination radicle then discussed. The section ends Obtain a flower model. As you in fruit? How do sperm cells in the pollen P grain reach the egg cells in the ovary? These hypocotyl with an explanation of seed dis- point out structuresLS on the persal and seed germination. model, have students name each steps in the reproductive cycle of anthophytes take place without water—an structure and explain its function. B Spinach and lettuce evolutionary step that Planning L1 B LS (above) are long- enabled flowering plants to Purchase peanuts for the Quick day plants that occupy nearly every envi- Demo. Extension flower in midsum- C Most plants are day-neutral. mer. ronment on Earth. Find flowers for Assessment. Linguistic Have students A Short-day plants, such as pansies Flowering in cucumbers (above), (above) and goldenrod, flower in tomatoes, and corn is not influ- Purchase bean seeds for the determine the meaning of late summer and fall or early spring. enced by a dark period. Bee orchid Ophrys Tech Prep. the terms androecium, gynoe- speculum and ovary Purchase beans and tetrazoli- cium, and perianth. Have them of a flower (inset) Short-day plants are induced to and garden peas. Most plant species um chloride for the Alternative assign the term sterile or non- WORD Origin flower by exposure to a long night. are day-neutral plants, which means Lab. sterileP to each flower part. L3 photoperiodism These are plants that usually form temperature, moisture or environ- Purchase tomato and peach for From the Greek flower buds in the fall when the days mental factors other than day length the Quick Demo. words photos, mean- are getting shorter and the nights are control their flowering times, as Assessment ing “light,” and Purchase corn and bean seeds periodos, meaning long, as shown in Figure 24.11A. shown in Figure 24.11C. The pho- for MiniLab 24-2. the ovary. In the ovule, a cell under- LS Performance Provide stu- “a period.” The Flowering occurs in the spring, as in toperiodism of flowers may ensure The Life Cycle of dents with a diagram of a typicalP flowering response crocuses, or in the fall as in strawberry that a plant produces its flowers at a an Anthophyte goes meiosis, producing haploid flower. Have them label the parts of a plant to periods plants. Long-day plants flower when time when there is an abundant popu- megaspores. One of these mega- of the flower and identify repro- of dark and light is days are longer than the nights, as lation of pollinators. This is important The life cycle of flowering plants spores will produce the female game- photoperiodism. is similar to that of conifers in many 1 Focus ductive parts. L1 shown in Figure 24.11B. Examples of because pollination is a critical event tophyte. The other three spores these are carnations, petunias, potatoes, in the life cycle of a flowering plant. ways. In both coniferophytes and die. In most flowering plants, the Bellringer LS anthophytes, the gametophyte gen- megaspore divides by mitosis three eration is contained within the times, producing eight nuclei. These Before presenting the lesson, sporophyte. Many of the reproduc- display Section Focus Trans- 4 Close Section Assessment eight nuclei are the embryo sac or tive structures are also similar. female gametophyte. Six of the nuclei parency 60 on the overhead pro- Discussion Understanding Main Ideas large shipment of short-day plants. What must However, anthophytes are the only are contained within six haploid cells, jector and have students answer 1. Compare and contrast sepals and petals. the florist do to induce flowering? plants that produce flowers and one of which is the egg cell. The two the accompanying questions. L1 Visual-Spatial Show students 2. Describe the male and female parts of a flower. fruits. Figure 24.12 summarizes the remaining nuclei, which are called ELL 3. Explain why squash flowers are considered SKILL REVIEWEVIEW pictures of flowers with dif- life cycle of flowering plants. polar nuclei, are both in one cell. ferent structuralP modifications. incomplete flowers. 6. Comparing and Contrasting Explain why the 4. How does photoperiodism influence flowering? structure of wind-pollinated flowers is often dif- This cell, the central cell, is located Have them point out the differ- Development of the at the center of the embryo sac. The ECTION OCUS ferent from that of insect pollinated flowers. For Transparency 60 Pollination S F P Use with Chapter 24, ent flower parts and speculate as Thinking Critically more help, refer to Organizing Information in female gametophyte egg cell is near the micropyle. The Section 24.3 to the advantage of the modifica- 5. In the middle of the summer a florist receives a the Skill Handbook. In anthophytes, the female game- other five cells are arranged as shown tion. L2 LS tophyte is formed in the ovule within in Figure 24.13.

666 REPRODUCTION IN PLANTS 24.3 THE LIFE CYCLE OF A FLOWERING PLANT 667 LS P

Section Assessment Resource Manager LS P 1. Both are leaflike structures. Petals are 4. Flowering is controlled by photoperiodism. bright colors. Sepals are usually green. For example, short-day plants flower when Section Focus Transparency 60 and 2. The male part is the stamen, which consists the days are short and nights are long. Master L1 ELL 1 The Brazilian birthwort gives off a scent that often resembles rotting flesh. How would this aid the plant in reproduction? Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. of the anther and filament. The female 5. The florist should cover the greenhouse 2 What other characteristics of this plant may help attract LS part is the pistil, which contains the ovary with tarps each afternoon to shorten the organisms for the purpose of aiding in reproduction?

and ovules. day and lengthen the night. P BIOLOGY: The Dynamics of Life SECTION FOCUS TRANSPARENCIES 3. Squash flowers are incomplete because 6. Wind-pollinated flowers are small and they do not have both pistils and stamens. lack petals. Insect-pollinated flowers have 666 brightly colored petals and nectar. 667 LS P

LS Building a Model Quick Demo Figure 24.12 Figure 24.13 In the life cycle of a flowering plant, the sporophyte gener- The eight nuclei produced by the Kinesthetic Use a plastic Visual-Spatial Show stu- ation nourishes and protects the developing gametophyte. megaspore form the female sandwich bag to represent a After fertilization, the new sporophyte, which is contained gametophyte of anthophytes. female gametophyte. Place three dents the tiny sporo- in a seed or fruit, is released from the parent plant. phyte inside a peanut. It is the small balls of clay of the same structure with two tiny leaves. Embryo sac color within the bag and explain CAUTION: Do not allow stu- that each ball represents a hap- Central cell dents to eat the peanuts as loid nucleus. (One is the egg and P Pollen sac Female gametophy the other two are the central some students may be allergic Anther with microspore Microspores cell.) Introduce two small balls of to them. in fours Ovary mother cells clay of a different color to the bag. Explain that each ball repre- LS Male Ovule sents the two sperm nuclei that Reinforcement gametophyte enter the female gametophyte. Visual-Spatial Provide stu- Egg cell Fuse one sperm with the egg and dents with a black line Sperm Micropyle explain that this represents the drawing of the life cycle of a Ovule with zygote, which is now diploid. flowering plant. Using colored Four Tube megaspore megaspores Development of the male cells within the pollen grain are the Fuse the other three nuclei. mother cell nucleus pencils, have them shade in the gametophyte tube cell and the generative cell. Explain that this represent the gametophyte stage and the Meiosis Female gametophyte The formation of the male gameto- When the pollen grains are mature triploid nucleus that forms with four nuclei sporophyte stage in two different phyte begins in the anther, as seen in the anther splits open. Depending on endosperm. Point out that GAMETOPHYTE colors. L1 ELL Figure 24.14. Haploid microspores the type of flower, the pollen may be together the fusing of the clay GENERATION P n Egg are produced by meiosis within the carried to the pistil by wind, water, or illustrates double fertilization. Microscope Activity anther. The microspores each divide animals. L1 Visual-SpatialP Have students Pollen into two cells. A thick, protective wall tube surrounds these two cells. This two- Pollination view prepared slides of Fertilization LS Lilium ovaries. Ask students to celled structure is the immature male In anthophytes, pollination is the Assessment P gametophyte, or pollen grain. The transfer of the pollen grain from the draw and label an ovule. L1 Knowledge Show students LS a flower pistil that has been cut P open to reveal the ovary. Ask them to point to where the following LS ResourceResource occur: growth of pollen tube, Figure 24.14 P ManagerManager Flowers Meiotic division of development of female gameto- Double each of many cells phyte, and double fertilization. LS fertilization Basic Concepts Trans- SPOROPHYTE within the anther Young Pollen tube L2 parency 42 and Master seedling GENERATION produces four L2 ELL P 2n Microspore microspores. These LS Zygote mother cell (2n) MEIOSIS microspores develop Pollen sac into the male gameto- Germinating Endosperm nucleus phyte or pollen grain seed Tube P nucleus LS Adult sporophyte P plant P LS Generative ANTHER cell Fruit Pollen grain Microspores LS Seed (male gametophyte) (n) LS 668 REPRODUCTION IN PLANTS 24.3 THE LIFE CYCLE OF A FLOWERING PLANT 669

BIOLOGYIOLOGY JOURNAL Internet Address Book

Flowering Plant Life Cycle Note Internet addresses that you find useful in the space Linguistic Have students write a below for quick reference. paragraph in their journal outlining the steps of a flowering plant’s life cycle. P Encourage them to illustrate the concepts with drawings. L2

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LS Reinforcement Revealing Misconceptions Figure 24.15 B The wind-pollinated flowers food. By producing nectar and Fertilization Ask students to explain how a The shape, color, and size of of this ragweed plant are attracting animal pollinators, animal- Once a pollen grain has reached Students may believe that “hay a flower reflect its relation- plant can reproduce sexually if its small and green and lack pollinated plants are able to promote the stigma of the pistil, several events fever” is an allergy to hay. ship with a pollinator. flowers are incomplete. Pollen structures that would block pollination without producing large take place before fertilization occurs. However, hay fever is an allergic wind currents. from the male flower can be car- amounts of pollen. Inside each pollen grain are two hap- reaction to the protein present in ried to the female flower by wind, A The butterfly uses its Some nectar-feeding pollinators are loid cells, the tube cell and the gener- pollen. Often, the pollen is pro- insects, or other animals. long proboscis to sip attracted to a flower by its color or ative cell. The tube cell nucleus duced by plants that bloom in the nectar that bees and scent or both. Some of the bright, directs the growth of the pollen tube early fall or spring. flies cannot reach. vivid flowers attract pollinators such as down through the pistil to the ovary, Tying to Previous C Bats sip nectar Knowledge from night- butterflies and bees. Some of these as shown in Figure 24.16. The gen- Enrichment blooming flow- flowers have markings that are invisi- erative cell divides by mitosis, pro- Ask students to answer the fol- ers with a ble to the human eye but are easily ducing two haploid sperm cells. The There are many different mecha- lowing questions. (a) Why is strong, musty seen by insects. Flowers that are polli- sperm cells are transported by the nisms to ensure pollination. Tell pollen needed for fertilization? It odor, such as nated by beetles and flies have a strong pollen tube through a tiny opening in students about the carrion flowers bananas and the ovule called the micropyle. Figure 24.16 that have a fragrance similar to contains sperm cells. (b) Why must some cacti. scent but are often dull in color. the pollen that fertilizes a flower Many flowers have structural adap- Within the ovule is the female In flowering plants, rotting flesh that attracts its polli- be from the same species as the tations that favor cross-pollination. gametophyte, composed of eight hap- the male gameto- nators—flies and beetles. One phyte grows through loid cells. One of the sperm unites with female flower? Chromosome num- This results in greater genetic varia- the pistil to reach the species of aquatic plant releases its bers and alleles must be identical for tion because the sperm from one the egg cell forming a diploid zygote, female gametophyte. pollen in a “pollen boat” that fertilization to occur. (c) What will plant fertilizes the egg from another. which begins the new sporophyte Double fertilization floats on the water’s surface until happen if pollen lands on the For example, the flowers of certain generation. The other sperm cell fuses involves two sperm it slides down the dimple created cell nuclei. One wrong species of flower? No pollen species of orchids resemble female with the central cell, which contains by the surface tension around wasps. The male wasps visit the the polar nuclei, to form a cell with a sperm cell unites tube will form and fertilization will with the egg nucleus nearby flowers. flower and attempt to mate with it triploid (3n) nucleus. This process, in not occur. and the other sperm and become covered with pollen, which one sperm fertilizes the egg and cell unites with the Concept Development which is deposited on orchids it may the other sperm joins with the central diploid central cell visit in the future. cell, is called double fertilization. of the female Corn has male and female flowers D Flowers polli- gametophyte. found on different parts of the nated by hum- same plant. Have students explain mingbirds are Double Fertilization what a corn tassel is, where the CD-ROM often tubular and colored bright red Pollen grain female corn flower is located, and Biology: The Dynamics or yellow but may The ultraviolet markings of E Stigma what corn silk is. The corn tassel is of Life have little scent. some flowers guide insects composed of all the stamens of many Exploration: Pollination to a flower’s nectar. Two sperm male flowers. The corn silk is com- Disc 3 Style nuclei posed of all the styles of many female anther to the pistil. Plant reproduc- ensure pollination. Most anthophytes flowers. The corn kernels on the cob tion is most successful when the pol- Pollen tube pollinated by animals produce nectar, are fertilized fruits of the plant. lination rate is high, which means which serves as a valuable, highly that the pistil of a flower receives concentrated food for visitors to the Ovary Tube nucleus enough pollen of its own species to flowers. Nectar is a liquid made up of fertilize the egg in each ovule. Many proteins and sugars. It usually col- anthophytes have elaborate mecha- lects in the cuplike area at the base of VIDEODISC One sperm nisms that help ensure that pollen the petals. Animals such as insects fertilizes the STV: Plants Central cell grains are deposited in the right place and birds brush up against the (2n) central cell What is a Seed? at the right time. Some of these are anthers while trying to get to the (3n) Unit 4, Side 3, 3 min. shown in Figure 24.15. Although it nectar. The pollen that attaches to Ovule One sperm Germination may seem wasteful for wind-polli- them can be carried to another fertilizes the Egg nucleus nated plants to produce such large flower, resulting in pollination. Some egg cell (2n) !7gb/Q~Ö" amounts of pollen, it does help insects also gather pollen to use as

670 REPRODUCTION IN PLANTS 24.3 THE LIFE CYCLE OF A FLOWERING PLANT 671

PortfolioPortfolio Cross- and Self-Pollination Visual-Spatial Have students pre- VIDEODISC CD-ROM pare a series of drawings that explain Biology: The Dynamics of Life Biology: The Dynamics of Life the concepts of cross-pollination and self- Double Fertilization (Ch. 24) Animation: Double Fertilization pollination. Instruct students to include Disc 1, Side 2, 49 sec. Disc 3 proper labels and titles for the drawings. Non-artistic students may be provided with P a flower outline that they can trace for !9TÑ" 670 their diagrams. L2 ELL P 671

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LS Quick Demo Double fertilization is unique to Seeds and Fruits Fruit formation CAREERS IN BIOLOGY CAREERS IN BIOLOGY anthophytes and is illustrated in As the seeds develop, the sur- Show students a tomato and a Figure 24.16. The triploid nucleus The embryo contained within a rounding ovary enlarges and Greens Keeper Career Path peach. Ask how the two plant will divide many times, eventually seed is the next sporophyte genera- becomes the fruit. A fruit is the struc- o you like to work outside? Is golf Courses in high school: WORD Origin parts are alike and how they forming the endosperm of the seed. tion. The formation of seeds and the ture that contains the seeds of an D your favorite sport? Then you biology, botany, chemistry, differ. Students may suggest endosperm The endosperm is food storage tis- fruits that enclose them help ensure anthophyte. Figure 24.17 shows how already know the value of a velvety mathematics that both have seeds but that From the Greek sue that supports development of the the survival of the next generation. the fruit of a blueberry develops from green fairway, which is the first College: two- or four-year degree words endon, mean- embryo in anthophyte seeds. requirement in becoming a greens one is a fruit and one is a veg- the ovary inside the flower. keeper. to become a crew supervisor ing “within,” and Many flowers contain more than Seed formation etable. Ask students to provide sperma, meaning A fruit is as unique to a plant as its Other education sources: on- one ovule. Pollination of these flowers After fertilization takes place, most Skills for the Job definitions for fruit and veg- “seed.” The endo- flower, and many plants can be identi- the-job training requires that at least one pollen grain of the flower parts die and the seeds A greens keeper maintains both etable. Use their definitions to sperm is storage fied by examining the structure of tissue found in the land on the stigma for each ovule con- begin to develop. The wall of the ovule the playing quality and the beauty of a Career Issue point out that a tomato is a their fruit. You are familiar with golf course. Beginning keepers usually learn seeds of many tained in the ovary. In a watermelon becomes the hard seed coat, which With so many issues and prob- fruit. If students are still not plants that develop fleshy fruits, such on-the-job and spend their days mowing the greens. Greens anthophytes. plant, for example, hundreds of pollen may aid in dispersal and helps protect lems in today’s world, ask students sure of the relationship, ask as apples, grapes, melons, tomatoes, keepers who want to manage large crews will need a two- or grains are required to pollinate a sin- the embryo until it begins growing and cucumbers. Other plants develop four-year degree in turf management and a certificate in if they think anyone should be how the seeds got inside the gle flower if each ovule is to be fertil- into a new plant. Inside the ovule, the dry fruits such as peanuts, sunflower grounds management. They must be thoroughly familiar concerned about the quality of a two structures and what was with different types of grasses and know how weather and ized. You are probably familiar with zygote divides and grows into the “seeds,” and walnuts. In dry fruits, the golf course. Have them explain present on the plant before the hundreds of watermelon seeds plant embryo. The triploid central wear affect them so they can keep fairways smooth and per- P ovary around the seeds hardens as the fectly green. Other careers in turf management including car- the reasons for their opinions. the tomato or peach appeared. that are the result of this process. cell develops into the endosperm. fruit matures. Some plant foods that ing for the grounds of shopping centers, schools, sports play- we call vegetables or grains are actu- ing fields, cemeteries, office buildings, and other locations. For More Information Figure 24.17 ally fruits, as shown in Figure 24.18. For more information on becom- LS A fruit consists of the seeds and Can you think of any vegetables that For more careers in related fields, be sure ing a greens keeper, students can Concept Development the surrounding mature ovary of are actually fruits? For example, to check the Glencoe Science Web Site. write to: a flowering plant. Fruit www.glencoe.com/sec/science Professional Grounds Show students an apple. Explain tomatoes are fleshy fruits that are often referred to as vegetables. Management Society that an apple is a “false fruit.” A When the eggs in the ovules of 120 Cockeysville Road, Suite 104 Explain that unlike most fruits, a blueberry flower have been Hunt Valley, MD 21031 which form from the ovary wall, fertilized, the petals, stamens, Figure 24.18 the fleshy part of an apple forms and stigma wither and fall A fruit is the ripened ovary of a Enrichment away. from the swollen receptacle. flower that contains the seeds or Visual-Spatial seed of the plant. The most Have students research the type of fruits: Ovary C The remains of the familiar fruits are those we con- Ovules sepals and some dried sume as food. cypsela, berry, pome, follicle, stamens usually can legume, capsule, and aggregate. be seen at the top. Sepals Ask them to create a visual that defines each fruit type and shows CD-ROM Fused examples of each. L3 Biology: The Dynamics petals of Life Stamens Animation: Fruit Formation B Fleshy fruits develop a juicy fruit Disc 3 wall full of water and sugars. VIDEODISC P Biology: The Dynamics B The wall of the ovary in a of Life blueberry becomes fleshy Fruit Formation (Ch. 25) and grows up and around the ovary as the seeds develop. Disc 1, Side 2, 39 sec. A Dry fruits have dry fruit walls. The ovary wall LS may start out with a fleshy appearance, as in !9^Ö" hickory nuts or bean pods, but when the fruit is fully matured, the ovary wall is dry.

672 REPRODUCTION IN PLANTS 24.3 THE LIFE CYCLE OF A FLOWERING PLANT 673

MEETING INDIVIDUAL NEEDS Cultural Diversity

English Language Learners The History of Chocolate seeds into a rich brown drink called choco- Visual-Spatial Have students prepare Fruits and Fiber Theobroma cacao is a native tree from Central late. Researchers are suspicious that the a table with the heads Haploid, Dip- Visual-Spatial Have students prepare America. After flowering, it produces large chemicals in chocolate, theobromine and loid, and Triploid across the top. Ask them a chart comparing the amount of pods that contain about 40 cacao beans. methylxanthin, may have an addictive qual- to group the following terms, phrases, or fiber in five fruits. They should explain why Because of its seeds, cacao was domesticated ity. This may explain why some individuals numbers beneath their correct head: a high fiber diet is considered beneficial. by the Mayas and Aztecs who turned the crave chocolate and chocolate products. sperm, 3n, pollen tube nucleus, egg, n, P L2 endosperm, central cell, fertilized egg, 2n. 672 L1 ELL 673

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LS Tying to Previous Figure 24.19 growth and development of the new A wide variety of seed- Knowledge B Clinging fruits, like plant. This period of inactivity in a Figure 24.20 dispersal mechanisms Ask students to define the term those of the cockle- mature seed is called dormancy. The Seeds can remain have evolved among bur and burdock, dormant for long Water and Seed polyploidy. Explain that it is esti- flowering plants. length of time a seed remains dor- are covered by periods of time. mated that between 35 and 50% hooks that stick to mant can vary from one species to Germination another. Some seeds, such as willow, Lupine seeds like of all flowering plants are poly- the fur or feathers these may germinate Kinesthetic Water must ploid. The most common poly- of passing animals magnolia, and maple remain dor- after remaining dor- be absorbed by seeds or the clothes of mant for only a few weeks after ploid condition is tetraploid or mant for decades. prior to germination in a passing humans. they mature. These seeds cannot 4n. Tetraploids are often bigger process called imbibition. The or more vigorous that the diploid survive harsh conditions for long periods of time. Other plants volume change that occurs plant and thus are more desirable produce seeds that can remain during imbibition can be mea- for agriculture and/or horticul- dormant for remarkably long peri- sured through water displace- ture. C Wind-dispersed seeds have adapta- ods of time, Figure 24.20. Even ment. tions that enable under harsh conditions, the seeds of Place 50 mL of water in a them to be held desert wildflowers and some conifers graduated cylinder. Add 10 aloft while they can survive dormant periods of 15 to For example, some germinate more bean seeds. The new level of drift away from their parent. 20 years. Scientists discovered readily after they have passed Figure 24.21 water less the original volume A The ripe pods of violets snap open ancient seeds of the East Indian through the acid environment of an The seeds of the equals the volume of the 10 CD-ROM with a pop, which sends a shower Lotus, Nelumbo nucifera, in China, animal’s digestive system. Others desert tree Cercidium seeds. Remove the seeds from of small seeds in all directions. Biology: The Dynamics which they have radiocarbon dated to require a period of freezing tempera- floridum have hard the cylinder and soak them in of Life be more than a thousand years old. tures, as do apple seeds, extensive seed coats that must water overnight. The following Seed dispersal pockets in the walls, which enable be cracked open in Animation: Seed Dispersal Imagine their amazement when these soaking in saltwater, as do coconut day, add 50 mL of water to the them to float and drift away from the order to germinate. Disc 3 A fruit not only protects the seeds seeds germinated! seeds, or certain day lengths. Recall graduated cylinder. Add the parent plant. The ripened fruits of This occurs when the VIDEODISC inside it, but also may aid in dispersing that the seeds of some conifers will seeds tumble down soaked beans and calculate those seeds away from the parent plant many plants split open to release Requirements for germination not germinate unless they have been Biology: The Dynamics rocky gullies in sudden their new volume. Have stu- and into new habitats. The dispersal seeds designed for dispersal by the Dormancy ends when the seed is exposed to fire. The same is true of rainstorms. of Life dents use the water-displace- of seeds, Figure 24.19, is important wind or by clinging to animal fur. ready to germinate. Germination is Seed Dispersal (Ch. 26) ment technique to calculate because it reduces competition for Orchid seeds are so tiny that they the beginning of the development of Disc 1, Side 2, 1 min. 9 sec. the percent of volume change sunlight, soil, and water between the resemble dust grains or feathers and the embryo into a new plant. The P parent plant and its offspring. Animals are easily blown about by the wind. absorption of enough water and the that occurs through imbibition. !9hÜ" such as raccoons, deer, bears, and birds The fruit of the poppy flower forms a presence of oxygen and favorable L2 ELL help distribute many seeds by eating seed-filled capsule that releases sprin- temperatures usually end dormancy, dry or fleshy fruits. They may carry kles of tiny seeds like a salt shaker as but there may be other requirements. it bobs about in the wind. Tumble- LS the fruit some distance away from the Water is important because it acti- P ResourceResource parent plant before consuming it and weed seeds are scattered by the wind vates the embryo’s metabolic system. spitting out the seeds. Or they may eat as the whole plant rolls along the Once metabolism has begun, the seed ManagerManager the fruit, seeds and all. Seeds that are ground. must continue to receive water or it CD-ROM Basic Concepts Trans- eaten may pass through the digestive will die. Just before the seed coat P system unharmed and are deposited Seed germination LS Biology: The Dynamics parency 43 and Master breaks open, the plant embryo begins in the animal’s wastes. Squirrels, At maturity, seeds are fully formed. to respire rapidly. Many seeds germi- of Life L2 ELL birds, and other nut gatherers may The seed coat dries and hardens, nate best at temperatures between Video: Germination Laboratory Manual, drop and lose some of the seeds they enabling the seed to survive condi- 25°C and 30°C. Arctic species germi- Disc 3 pp. 171-178 L2 LS collect, or even bury them only to tions that are unfavorable to the par- nate at lower temperatures than do VIDEODISC P forget where. These seeds can then ent plant. The seeds of some plant tropical species. At temperatures Biology: The Dynamics germinate far from the parent plant. species must germinate immediately below 0°C or above 45°C, most seeds of Life Plants, such as water lilies and or die. However, the seeds of some won’t germinate at all. Germination (Ch. 27) coconut palms that live in or near plant species can remain in the soil Some seeds have special require- Disc 1, Side 2, 25 sec. P water produce fruits or seeds with air until conditions are favorable for ments for germination, Figure 24.21. LS !9rá" P 674 REPRODUCTION IN PLANTS LS Alternative Lab Materials seeds in half. use care when working with chemicals. Assessment canned kidney beans, paper cup, water, 2. Place all seeds split-side up onto two LS Analysis Portfolio Design an experiment dried kidney beans, wax paper, labels, sheets of wax paper. Mark each paper Respiring Seeds 1. Tetrazolium indicates cell respiration when it to determine how many seeds in a seed P tetrazolium solution in dark dropper bot- with a label indicating seed treatments. turns pink. Which seed treatment carried on packet are alive. Use the Performance tles (add 1 g of 2,3,5-triphenyl tetrazolium 3. Add a drop of tetrazolium to each cut Purpose cell respiration? Why? Uncanned seeds are Task Assessment List for Designing an chloride to 100 mL distilled water) surface. Wait 20-30 minutes. Record in To compare the rate of respiration in ger- germinating and require energy; canned Experiment in PASC, p. 23. L3 which seeds and where in the seeds a minating and nongerminating seeds. Procedure seeds are dead. LS Give the following directions to students. pink color appears. Note: Tetrazolium 2. The darker the pink color, the greater the 1. Soak ten kidney bean seeds overnight can be diluted and discarded down the rate of respiration. Which seed part carries in water. The next day, split each seed sink, but the bean seeds cannot be dis- on the greatest rate of respiration? Why? in half. Split ten canned kidney bean carded in the sink. Caution students to Embryo; rapid growth requires more energy. 674 P 675

LS MiniLab 24-2 Figure 24.22 certain wildflower species, including cotyledons and the plant’s first leaves. P 3 Assess Many wildflowers require fire for their seeds to germinate. lupines and gentians, Figure 24.22. As the stem grows larger and the MiniLab 24-2 Observing Purpose This is especially true in prairie environments where fires The germination of a typical dicot leaves turn green, the plant can pro- are periodically set to induce the germination of prairie embryo is shown in Figure 24.23. duce its own food through photosyn- Check for Understanding To compare dormant and germi- wildflower seeds. Looking at Germinating Seeds Seeds Have students explain how the nating monocotLS and dicot seed Once the seed coat has been softened thesis. To learn more about germinat- are made up of a plant embryo, a seed embryos. by water, the embryo starts to ing seeds, try the MiniLab shown here. coat, and in some plants, a food- words in each of the following emerge from the seed. The first part storage tissue. Monocot and dicot pairs are related. L2 Process Skills of the embryo to appear is the Vegetative reproduction seeds differ in their internal structures. a. pollen tube—double fertiliza- observe and infer, compare and embryonic root called the radicle The roots, stems, and leaves of Procedure tion contrast (RAD ih kul). The radicle grows down plants are called vegetative structures. ! Obtain from your teacher a soaked, b. epicotyl—hypocotyl Safety Precautions into the soil and develops into a root. When these structures produce a new ungerminated corn kernel (monocot), c. dormancy—germination The portion of the stem nearest the plant, it is called vegetative reproduc- a bean seed (dicot), and corn and Corn seed Advise students to use caution germination seed is called the hypocotyl (HI poh tion. Vegetative reproduction is com- bean seeds that have begun to with razor blades and always to Reteach kaht ul). In some plants, the first part mon among anthophytes. Some mod- germinate. P cut away from the body. of the stem to push above ground is ified stems of anthophytes, such as @ Remove the seed coats from each of the ungerminated Have students indicate when or Teaching Strategies an arched portion of the hypocotyl. potato tubers, can produce a new seeds, and examine the structures inside. Use low-power where in the life cycle each term As the hypocotyl continues growing, plant. Potatoes will grow new stems magnification. Locate and identify each structure of the in the Check for Understanding Soak some seeds 24 hours and embryo and any other structures you observe. it straightens, bringing with it the from their “eyes” or buds. Farmers applies. L2 others 72 hours prior to use. # Examine the germinating seeds. Locate and identify the LS After the 72-hour seeds have make use of this feature when they structures you observed in the dormant seeds. cut potato tubers into pieces and been soaking for 24 hours, wrap Figure 24.23 Extension plant them. The buds on these sec- Analysis them in moist paper towels and Germination of a bean seed is stimulated by Have students research the warm temperatures and water, which softens Hypocotyl tions grow new shoots that produce 1. Diagram the dormant embryos in the soaked seeds, and place them in sealed plastic bags. the seed coat. label their structures. mechanism responsible for roots entire new plants. Advise students to lay the corn Although cloning animals is a rela- 2. Diagram the germinating seeds, and label their structures. growing down and stems growing on its flat side while cutting. A The radicle will Radicle B The hypocotyl tively new phenomenon, gardeners 3. List at least three major differences you observed in the up. L3 internal structures of the corn and bean seeds. P Expected Results become the pri- Cotyledon is the first part have relied for years on cloning to mary root. of the stem to reproduce plants. Using vegetative Germinating seeds have larger Seed coat appear. reproduction to grow numerous plants Assessment embryos. Primary root from one plant it is frequently referred to grow plants by tissue culture. Tiny PerformanceLS Provide stu- Analysis to as vegetative propagation. Some pieces of plants are placed on nutri- dents Pwith a sliced peach or cher- 1. Labels should include cotyle- plants, such as geraniums, can be ent agar in test tubes or petri dishes. ry half and a sliced open flower. don(s), embryo. propagated by planting cuttings, which The plants produced by cuttings and Have them locate and name the 2. Diagrams of dicot should are pieces of the stem or a leaf that tissue cultures contain the same following structures: ovule before include cotyledons, embryo, has been cut off another plant. Even genetic makeup as the original plants. and LS after fertilization, ovary epicotyl, radicle, plumule, smaller pieces of plants can be used Therefore, they are botanical clones. before and after fertilization, and hypocotyl. Diagrams of Epicotyl embryo. L1 monocot should include only cotyledon and embryo. Withered cotyledons Section Assessment 3. Monocot has one cotyledon, Cotyledon Hypocotyl Understanding Main Ideas Thinking Critically small embryo, is slow to ger- 1. What is the relationship between the pollina- 5. Describe the formation of the female gameto- 4 Close minate, and its embryo parts tion of a flower and the production of one or phyte in a flowering plant. are hard to differentiate. C As the hypocotyl D As new leaves more seeds? Discussion SKILL REVIEWEVIEW Dicot seed has two cotyle- straightens, the mature, the 2. What part of an anthophyte flower becomes Watermelons have numerous plant’s first leaves, Secondary cotyledons the fruit? 6. Making and Using Tables Make a table that dons, larger embryo, and eas- the cotyledons, roots wither and black seeds and some small white 3. Describe the process of double fertilization in indicates whether each structure of a flower is P ily seen embryo parts. are exposed to fall away. anthophytes. involved in pollination, fruit formation, seed pro- seeds. Ask students to speculate sunlight. 4. Explain how the production of nectar could duction, or seed dispersal. For more help, refer to what the small white seeds found enhance the pollination of a flowering plant. Organizing Information in the Skill Handbook. in a watermelon might be. They Assessment are unfertilized ovules. L2 Performance Provide stu- LS dents with seeds. Have students 676 REPRODUCTION IN PLANTS 24.3 THE LIFE CYCLE OF A FLOWERING PLANT 677 classify each seed after removing the seed coat. Use the Perform- ance Task Assessment List for PortfolioPortfolio Making and Using a Classification Resource Manager Section Assessment System in PASC, p. 49. L2 Modeling Seed Dispersal 1. Pollination transports sperm to the fuses with the central cell to form a 3n loid megaspores. One of theseP megas- Reinforcement and Study Guide, Kinesthetic Provide students with female gametophyte. Inside the ovule, cell. pores will undergo three mitotic p. 108 L2 ELL a strip of Velcro, a piece of fabric, the sperm cells are involved in double 4. Nectar is a source of nutrition for ani- divisions, producing eight nuclei. These BioLab and MiniLab Worksheets, cotton batting, tape, string, clay, stiff fertilization. One pollen grain is re- mal pollinators such as insects and bats; eight nuclei make up the embryo sac or p. 110 L2 paper, and scissors. Have them use the quired for the production of each seed. they get pollen on them as they try to female gametophyte. LS Content Mastery, pp. 117, 119-120 P materials to prepare models that show 2. the ovary wall reach the nectar. As these animals trav- 6. pollination: anther, stamen, stigma; L1 different means of seed dispersal. Models Double fertilization occurs when one el from flower to flower, they cross-pol- fruit formation: ovary, and ovule; seed P 3. P may imitate attaching to animal fur or sperm unites with the egg cell, forming linate the flowers. production: ovule, egg; seed dispersal: 676 floating in air. L1 ELL the 2n zygote and the other sperm cell 5. In the ovule, meiosis produces four hap- ovary 677 P LS LS P LS P LS P LS LS P LS LS VESTIGATE INVESTIGATE IN E INVESTIGATE Examining the Structure pollen-filled anther on the tip. 5. Examine the anther under low of a Flower Note the number of stamens. and high power of your micro- 3. Locate the pistil. The stigma at scope. The small, dotlike struc- P the top of the pistil is often sticky. tures are pollen grains. lowers are the reproductive structures of anthophytes. Seeds that The style is a long, narrow struc- 6. Slice the ovary in half length- Time Allotment F develop within the flower are carried inside a fruit. Seeds provide ture that leads from the stigma to wise with the razor blade. AANALYZENALYZE ANDAND CCONCLUDEONCLUDE One class period an extremely important form of reproduction in flowering plants. the ovary. Mount one half, cut side fac- LS 4. Place an anther from one of the ing up, on a microscope 1. Stamens, petals, and sepals Process Skills Flowers come in many colors and shapes. Often their colors or shapes are stamens onto a microscope slide slide. related to the manner in which pollination takes place. The major organs will be in multiples of 3 if a observe and infer, use the micro- and add a drop of water. Cut the 7. Examine the ovary section monocot, multiples of 4 or 5 scope, compare and contrast, of a flower include the petals, sepals, stamens, and pistils. Some flowers anther into several pieces with with a hand lens or stere- if a dicot. One pistil and the razor blade. CAUTION: omicroscope. The interpret data are incomplete, which means they do not have all four kinds of organs. ovary will be present. You will study a complete flower. Always take care when using a many, small, dotlike Safety Precautions razor blade. structures that fill the 2. thousands of pollen grains, 10 Some students may be allergic two ovary halves are to 100 ovules to the chemicals used in pre- ovules. Each ovule 3. Yes; the flower increases the REPARATION served specimens. PPREPARATION contains an egg probability of a pollen cell cell that is not landing on the correct stigma Caution students against rub- Problem microscope 2 coverslips bing their eyes with their visible under low by producing and releasing a What do the parts of a flower look single-edged dropper power. A tiny large number of pollen hands because of the preserva- like? How are they arranged? razor blade water stalk connects each grains. tive. Always have students ovule to the ovary wall. Objectives wash their hands thoroughly Safety Precautions 8. Identify the ovary and ovules. after handling preserved speci- In this BioLab, you will: Always wear goggles in the lab. 9. Make a diagram of the flower, Assessment mens. Observe the structures of a flower. Handle the razor blade with extreme labeling all its parts. Color the Identify Handle the razor blade with the functions of flower parts. caution. Always cut away from you. female reproductive parts red. Knowledge Provide stu- extreme caution. Always cut Use caution when working with a dents with diagrams of a flower Materials Color the male reproductive parts away from the body. microscope and slides. Wash your green. Color the remaining parts other than that used in this flower—any complete flower that is hands with soap and water after han- blue. BioLab. Have them label and available locally, such as phlox, lily, REPARATION dling plant material. indicate the general function of all PPREPARATION or tobacco flower important structures. Use the hand lens (or stereomicroscope) Skill Handbook NALYZE AND ONCLUDE Performance Task Assessment Alternative Materials colored pencils (red, green, blue) Use the Skill Handbook if you need AANALYZE AND CCONCLUDE 2 microscope slides List for Making Observations and additional help with this lab. Inferences in PASC, p. 17. L1 Do not use composite species 1. Observing How many stamens are Going Further of flowers such as sunflower, present in your flower? How many daisy, or dandelion. Project Use a field guide to identify com- PPROCEDUREROCEDURE pistils, ovaries, sepals, and petals? Going Further Preserved slides that show 2. Comparing and Contrasting mon wildflowers in your area. Most field identifications are made on the basis of eggs within the ovule are avail- 1. Examine your flower. Locate the Make a reasonable estimate of the color, shape, numbers, and arrangement of Provide students with a compo- able from supply houses. sepals and petals. Note their number of pollen grains in the flower parts. If collecting is permitted, pick a site flower such as a sunflower Preserved flowers are available numbers, size, color, and arrange- anther and the number of ovules in few common flowers to press and make or daisy. Have them determine at any time of the year from ment on the flower stem. an ovary of your flower. into a display of local flora. the locations of the individual 3. Interpreting Data biological supply houses. A 2. Remove the sepals and petals Which pro- To find out more about florets and their various flower from your flower by gently duces more? Pollen grains by one P disadvantage to such flowers is flowers, visit the Glencoe parts. L2 that the preservative tends to pulling them off the stem. Locate anther? Ovules produced by one Science Web Site. www.glencoe.com/sec/science discolor flower parts, espe- the stamens, each of which con- ovary? Give a possible explanation cially petals and sepals, which sists of a thin filament with a for your answer. will appear dull green. LS 678 24.3 THE LIFE CYCLE OF A FLOWERING PLANT 679

P PPROCEDUREROCEDURE Resource Manager Teaching Strategies not attempt to observe ovules under the If necessary, review proper use of the BioLab and MiniLab Worksheets, When preparing the anther wet mount, microscope in order to observe egg cells. stereomicroscope. LS it may be helpful for students to squash the Students can work in groups of two to pp. 111-112 L2 preparation using their thumb and a piece three for this BioLab. Data and Observations of lens paper over the coverslip. Advise stu- Show students how to remove the petals Student diagrams, when colored properly, dents to press down firmly to avoid crack- and sepals. should show the petals and sepals as blue, ing the coverslip, or use plastic coverslips You may wish to appoint certain students as pistil as red, and stamens as green. for this wet mount. lab helpers. These students can be called upon 678 Eggs will not be visible; students should by their classmates for help and guidance. 679 P

LS BIO BIO Chapter 24 Assessment Chapter 24 Assessment Technology Technology Hybrid Plants SSUMMARYUMMARY Main Ideas P Section 24.1 Main Ideas Vocabulary Summary statements can be used by Purpose If you’ve looked through any seed catalogs lately, you may have noticed phrases like “new In mosses, a gametophyte forms archegonia and megaspore (p. 658) students to review the major con- micropyle (p. 659) this season!” or “improved yield,” or “sweeter-tasting.” Sometimes the designation “F1” Life Cycles of antheridia. The gametophyte is dominant. cepts of the chapter. Students explore old and new microspore (p. 658) is given beside the names of some plant varieties. All of these plants are hybrids that methods ofLS plant hybridization. Mosses, Ferns, In ferns, the prothallus forms archegonia and protonema (p. 655) have been produced in experiments conducted by plant breeders. and Conifers antheridia. The sporophyte is dominant. vegetative reproduction Using the Vocabulary Background (p. 654) In conifers, cones produce spores that form To reinforce chapter vocabulary, use male or female gametophytes. The pollen grain Seed saver organizations encour- the Content Mastery Booklet and age home gardeners and farmers or thousands of years, humans have influ- produces sperm, which fertilizes the egg. The embryo is protected by a seed. the activities in the Interactive Tutor to grow open-pollinated, or non- Fenced the breeding of plants, especially food for Biology: The Dynamics of Life on hybrid, varieties of vegetables and crops and flowers. Today’s plant breeders create hybrid strains with a variety of desired character- the Glencoe Science Web Site. flowers. These natural varieties can Section 24.2 Main Ideas Vocabulary www.glencoe.com/sec/science reliably be reproduced from seed istics, such as more colorful or fragrant flowers, tastier fruit, higher yields, or increased resistance Flowers are made up of four organs: sepals, anther (p. 662) pollinated in the wild by wind, Flowers and petals, stamens, and pistils. day-neutral plant (p. 666) to disease. long-day plant (p. 666) insects, or birds. Many growers Flowering Photoperiodism affects the timing of ovary (p. 662) All Chapter like to raise heirloom varieties of The perfect ear of corn The first step in creat- flower production. petals (p. 661) Assessment nonhybrids that are becoming ing a hybrid is the selection of parent plants with photoperiodism (p. 663) questions and answers have been rare because an increasing num- desirable characteristics. A breeder might select a pistil (p. 662) validated for accuracy and suitabili- corn plant that ripens earlier in the season or one sepals (p. 661) ber of hybrid varieties are offered short-day plant (p. 666) ty by The Princeton Review. every year. Open-pollinated vari- that can be sown earlier in the spring because its seeds germinate well in cool, moist soil. stamens (p. 662) eties help maintain genetic diver- The next step is to grow several self-polli- NDERSTANDING AIN DEAS sity in plant populations. Seeds nated generations of each plant to form a true- Technician performing hybridization studies UUNDERSTANDING MMAIN IIDEAS Section 24.3 Main Ideas Vocabulary produced by hybrids are either breeding line that always shows the desired char- sterile or tend to revert to unwant- acteristic. To do this, each plant must be pre- cells of leaves or seedlings, then uses electricity The male gametophyte is produced by a dormancy (p. 675) 1. b The Life Cycle microspore in the anther. The female gameto- double fertilization ed characteristics of the parent vented from cross-pollinating with other corn. or chemicals to fuse cells of two different species. (p. 671) 2. c phyte is produced by a megaspore in the ovule. generation. The female flowers, called silks, grow near the Some of these fused cells have been successfully of a Flowering endosperm (p. 672) middle of the corn stalk. The breeder covers cultured in the lab and grown into adult plants, Plant Sperm are transported by a pollen tube to the germination (p. 675) Teaching Strategies each flower to prevent wind-borne pollen from though none have produced seeds. ovule, where fertilization takes place. hypocotyl (p. 676) fertilizing it. The pollen-producing male tassels Recombinant DNA technology has been used In double fertilization, one sperm joins with the polar nuclei (p. 667) Review with students Mendel’s are removed and the breeder uses their pollen to to insert specific genes into the chromosomes of a radicle (p. 676) experiments with garden peas egg to form a zygote. The second sperm joins hand-pollinate each flower. plant. This technique helps produce plants that the central cell to form endosperm. and the genetic crosses discussed Once each true-breeding line has been estab- are resistant to frost, drought, or disease. The ovary wall becomes the fruit. in Chapter 10. lished, the real experimentation begins. Breeders Fruits and seeds are modified for dispersal. Point out that plant breeders cross different combinations of true-breeding INVESTIGATING THE TECHNOLOGY Seeds can stay dormant for long periods of time. don’t necessarily know whether a lines to see what characteristics the resulting F1 Analyzing Concepts desired characteristic is regulated hybrids will have. These trials show which of the Why do seed companies true-breeding lines reliably pass their desired recommend not saving seeds from hybrid vari- by one gene or many genes. This characteristic to hybrid offspring, and which eties to plant the following year? (Hint: The off- is one reason why field trials of crosses produce seeds that the breeder can mar- spring of self-pollinated hybrids constitute the F2 many different crosses are often ket as a new, improved variety of corn. generation.) UUNDERSTANDINGNDERSTANDING MMAINAIN IIDEASDEAS required to obtain hybrid vari- 2. Flowers that are dull in color and have no eties with specific characteristics. Applications for the future To find out more about hybrid 1. Pollen and nectar produced by flowers pro- nectar yet have a strong scent might be polli- Cell culture and genetic engineering tech- seeds, visit the Glencoe Science vide ______for butterflies and bees. nated by ______. Investigating the Technology nologies are new plant breeding techniques. Web Site. a. protection c. shelter a. bees c. beetles b. d. To ensure that a new crop will Protoplast fusion removes the cell walls from the www.glencoe.com/sec/science b. food d. fruit butterflies hummingbirds have the characteristics of the hybrid, a farmer must purchase 680 REPRODUCTION IN PLANTS CHAPTER 24 ASSESSMENT 681 seeds from the plant breeder each time a new crop is planted. Seed for the desired hybrid can be Going Further Internet Address Book Resource Manager obtained only by cross-pollinat- Ask students to compare and contrast ing the same line of parent plants. Note Internet addresses modern methods of creating hybrids with VIDEOTAPE Chapter Assessment, pp. 139-144 F1 hybrids produce offspring with that you find useful in the techniques used by Gregor Mendel in MindJogger Videoquizzes MindJogger Videoquizzes variable characteristics, not nec- the space below for quick reference. his experiments with garden peas during Chapter 24: Reproduction in Plants Computer Test Bank essarily those of the hybrid. For Have students work in groups as they play the 1800s. L2 BDOL Interactive CD-ROM, Chapter 24 examples, see the Punnet squares the videoquiz game to review key chapter quiz and discussion of F2 hybrids in concepts. Chapter 10. 680 681

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LS Chapter 24 Assessment Chapter 24 Assessment Chapter 24 Assessment Chapter 24 Assessment

3. b 3. Moss gametophytes are ______and form 9. A(n) ______is one that has all four organs: 22. How does dormancy contribute to the sur- 23. The gametophyte is protected AASSESSINGSSESSING KKNOWLEDGENOWLEDGE && SSKILLSKILLS 4. d gametes by ______. sepals, petals, stamens, and pistils. vival of a plant species in a desert ecosystem? and nourished by the sporo- a. diploid; meiosis c. diploid; mitosis a. short-day plant c. incomplete flower 5. a 23. In what ways can the relationship between the The graph below provides data from an phyte. b. haploid; mitosis d. haploid; meiosis b. long-day plant d. complete flower 6. c gametophyte and sporophyte in seed plants experiment that tests the effects of ionizing 24. Mammals may have selected 7. b 4. By eating fruit, mammals help ______. 10. The response of flowering plants to the dif- be regarded as good for the gametophyte? radiation on the germination of seeds. only certain fruits for their diet 8. d a. fertilize flowers c. photoperiodism ference in the duration of light and dark peri- 24. Explain why a scientist might hypothesize and thus aided in dispersal and 9. d b. nastic movement d. disperse seeds ods in a day is called ______. that the eating habits of herbivorous mam- Germination of Beans After survival of these species. a. photoperiodism c. pollination Exposure to Radiation 10. a 5. While feeding, butterflies and bees carry mals affected the evolution of fruits in flow- b. nastic movement d. dormancy 11. endosperm pollen from flower to flower, causing ering plants. 100 ______. 11. A triploid cell resulting from double fertiliza- 12. pistil THINKINGHINKING CRITICALLYRITICALLY a. pollination c. germination tion becomes the ______. T C 13. gametes HINKINGHINKING RITICALLYRITICALLY 50 b. dormancy d. photoperiodism 12. TT CC 14. antheridia, archegonia The structure marked 25. The plant is probably pollinated 6. The heart-shaped structure formed by a A in the photograph 15. microspores 25. Observing and Inferring A plant species by animals. developing fern spore is called a ______. is the ______. Percent germination 16. dormancy produces heavy, spiked pollen grains. What 0 26. The moss and fern sporophytes a. protonema c. prothallus conclusion can you draw about the plant’s Control High Medium Low 17. ovary Exposure level both develop from a diploid b. sporophyte d. frond pollination method? 18. short, long zygote in the archegonium of 7. Which of the following plants do NOT pro- 26. Comparing and Contrasting Compare and 19. micropyle Using a Graph the gametophyte. The moss duce pollen? A contrast the formation of a moss sporophyte Use the graph to answer the 20. vegetative propagation a. pine tree c. apple tree and a fern sporophyte. following questions. sporophyte will remain depen- b. d. dent upon the gametophyte, mosses corn 27. Formulating Hypotheses Form a hypothesis 1. Which group of beans had the highest 8. Which of the following is a fern gameto- 13. The gametophyte produces ______that are that explains why the primary root is the first percentage of germination? whereas the fern sporophyte AAPPLYINGPPLYING MMAINAIN IIDEASDEAS phyte? haploid. part of the plant to emerge from a germinat- a. control will eventually survive on its a. c. 14. In ferns, sperm released by the ______fer- ing seed. b. high-exposure level own. c. medium-exposure level 21. Seeds store food intended for tilize eggs in the ______. 28. Concept Mapping Complete the concept 27. The primary root anchors the d. low-exposure level use by the embryo plant. 15. Male pinecones produce ______that will map by using the following vocabulary terms: seed and obtains needed water 22. Seeds will remain alive until develop into the male gametophyte, or pollen pistil, microspore, anther, stamen, ovary, 2. As the radiation dose increases, germi- from the soil for further growth water becomes available for grain. megaspores. nation ______. and development of the plant. germination. 16. a. increases c. stops 28. 1. Pistil; 2. Megaspores; 3. Ovary; b. d. The period of inactivity in a mature seed is Flowers have called ______. b. decreases d. is not affected 4. Stamen; 5. Microspores; 17. After pollination, a pollen tube grows down- female parts male parts 3. When beans are given a low dose of 6. Anther radiation, ______germinate. ward through the pistil to the ______. 1. 4. a. 25 percent c. none 18. A short-day plant is more likely to flower that produce that produce b. 50 percent d. 100 percent when the days are ______and the nights are ______. 2. 5. 4. When beans are given a medium dose of radiation, ______germinate. 19. in an in an During fertilization in anthophytes, the two a. 12.5 percent c. 37.5 percent 1. a sperm cells enter the ovule through an open- 3. 6. b. 25 percent d. 50 percent 2. b EST AKING IP ing called the ______. TTEST––TTAKING TTIP 5. Designing an Experiment Design an 3. a 20. Growing new plants from cuttings or tissue experiment on bean plants in which the 4. a Plan Your Work and Work Your Plan culture is called ______. CD-ROM 5. Bean plants that have just Set up a study schedule for yourself well in ad– following hypothesis is tested: Bean For additional review, use the assessment plants exposed to ionizing radiation will emerged from the soil are vance of your test. Plan your workload so that you options for this chapter found on the Biology: The not grow as tall as those that are not divided into four groups: do a little each day rather than a lot all at once. AAPPLYINGPPLYING MMAINAIN IIDEASDEAS Dynamics of Life Interactive CD-ROM and on the The key to retaining information is to repeatedly Glencoe Science Web Site. exposed. one the control that is not review and practice it. 21. You eat peas, beans, corn, peanuts, and cere- www.glencoe.com/sec/science irradiated, another given als. Why are seeds a good source of food? a high dose, another given a medium dose, and 682 CHAPTER 24 ASSESSMENT CHAPTER 24 ASSESSMENT 683 another a low does of radiation. The heights of the plants are measured and recorded for the duration of the experi- ment.

682 683 Plants BBIOIODDIGESTIGEST BBIOIODDIGESTIGEST BIOIODIGESTIGEST BBIOIODDIGESTIGEST For a preview of the plant unit, study this BioDigest before you read the chapters. Club Mosses Horsetails National Science Education Standards After you have studied the plant chapters, you can use the BioDigest to review the unit. Club mosses are non-seed plants in the divi- Horsetails are non-seed vascular plants in UCP,.1, UCP.2, UCP.5, C.4, C.5, sion Lycophyta. They possess vascular tissue and the division Sphenophyta. They are commonly 2 Teach C.6, F.4 are found primarily in moist environments. found growing in areas with damp soil, such as Species that exist today are only a few centime- stream banks and sometimes along roadsides. Microscope Activity Plants ters high, but they are otherwise similar to fossil Present-day horsetails are small, but their Lycophytes that grew as high as 30 m and formed ancestors were treelike. Visual-Spatial Have students arth is virtually covered with plants. Plants provide food a large part of the vegetation of Paleozoic view mosses, liverworts, and Prepare forests. The hollow, and shelter for multitudes of organisms. Through the hornworts with a stereomicro- E jointed stems scope. Ask students to describe Purpose process of photosynthesis, they transform the radiant energy Ferns of horsetails are surrounded their observations orally or in This BioDigest can be used as an of sunlight into chemical energy in food and release oxygen Ferns, division Pterophyta, are the most well- by whorls of writing in their journals. If possi- known and diverse of the non-seed vascular introduction to or an overview of to the atmosphere. All plants are multicellular eukaryotes. Mosses often grow in scalelike leaves. ble, supply sporophytes and the structures and functions of plants. They have leaves called fronds that grow Plant cells are surrounded by a cell wall made of cellulose. masses that form thick up from an underground stem called the rhi- gametophytes with male and carpets plants. If time is limited, you may zome. Ferns are found in many different habitats, female reproductive structures As in all vascular wish to use this unit summary to vascular tissues to move water and nutrients from including shady forests, stream banks, roadsides, plants, the sporo- and ask students to compare the teach about plants in place of the Non-Seed Plants one part of the plant to another, they cannot and abandoned pastures. phyte of this club characteristics of these structures Non-seed plants reproduce by forming spores. grow more than a few inches tall. chapters in the Plants unit. moss is the domi- A spore is a haploid (n) reproductive cell, pro- and generations. L2 nant generation. duced by meiosis, which can withstand harsh envi- Fern spores develop Spores develop at Key Concepts ronmental conditions. When conditions become VITALITAL STATISTICS in clustered structures the base of special favorable, a spore can develop into the haploid, Quick Demo Students learn about the charac- Non-Seed Plants called sori, usually leaves that form Quick Demo gametophyte generation of a plant. A spore will teristics of the major plant divi- Numbers of species: found on the under- cone-shaped struc- become either a female or male gametophyte. sions. They are introduced to the Bryophyta—mosses, 20 000 species sides of fronds. tures called strobili. Visual-Spatial If horse- alternation of generations; the Lycophyta—club mosses, 1000 species tails grow in your area, Mosses, Liverworts, and Sphenophyta—horsetails, 15 species bring several stems into the distinctions between non-seed Hornworts P Pterophyta—ferns, 12 000 species classroom. Show students that and seed plants; pollination and Mosses, liverworts, and hornworts are three Anthocerophyta—hornworts, 100 species fertilization; and the adaptive divisions of non-seed, nonvascular plants that live Hepatophyta—liverworts, 6500 species the stems come apart fairly value of flowers, seeds, and fruits. in cool, moist habitats. Because they have no easily at the nodes, and that the stems are hollow.LS Have them examine the strobili, if FFOCUSOCUS ONON AADAPTATIONSDAPTATIONS these are present. Point out 1 Focus Sporophyte that the silica in the stems Alternation of Generations Sperm gives horsetails a scouring-pad Bellringer Capsule Antheridium quality and is the source of Sporophyte Generation The Male reproductive P Visual-Spatial Bring an he life cycle of most plant species Gametophyte Generation zygote develops into an embryo, which organ the common name “scouring assortment of live plants T alternates between two stages, or A gametophyte is haploid (n) and pro- grows into the sporophyte generation of rush.” generations. The sporophyte generation duces eggs and sperm. In mosses, the the moss. The sporophytes grow out of the Egg into the classroom, including produces spores, which develop into the gametophyte is the familiar soft, green tip of the female branches of the gameto- Archegonium mosses, horsetails, and club gametophyte generation. The gameto- growth that covers rotting logs or moist phyte and consist of capsule-topped stalks. Female LS mosses, if available. Include a phyte produces gametes. In nonvascular soil. The tiny moss gametophytes pro- Cells inside each capsule undergo meiosis reproductive organ small potted pine or other plants, the gametophyte is larger and duce male and female branches. Sperm to form haploid (n) spores. Quick Demo more conspicuous than the sporophyte. cells produced by the male branches conifer, and several potted flow- In vascular plants, the sporophyte domi- must swim through rain or dew to reach Visual-Spatial Show ering plants. Ask students to The leafy gameto- nates. The gametophyte of a vascular the egg cells produced by the female The green, leafy phyte is haploid. plant is extremely small and may remain branches. Fertilization takes place inside students young fern fid- observe each plant and make a growth of this moss P The spore stalks buried in the soil or inside the body of the female reproductive organ and a dleheads and sori on the list of its characteristics in their is the gametophyte. and capsules are the sporophyte. diploid (2n) zygote is produced. The brown stalks topped Gametophyte under-side of a fern frond. journals. L1 diploid. with spore-filled capsules In the spring, fiddleheads are 684 are the sporophyte. 685 sometimes available in spe- LS cialty markets as a food item. AssessmentAssessment PlannerPlanner If a live fern is available, show students the underground Look for the following logos for strategies that emphasize different learning modalities. stem (rhizome) from which CD-ROM Multiple Performance Assessment P Kinesthetic Quick Demo, Linguistic Visual Learning, Assessment, TWE, p. 687 roots grow down and fronds Biology: The Dynamics p. 686; Meeting Individual p. 688; Extension, p. 689 of Life Learning Knowledge Assessment grow up. P Needs, p. 686 Naturalist Biology Journal, Assessment, TWE, p. 688 Animation: Life Cycle of a Moss Visual-Spatial Microscope p. 687 Disc 3 Styles BioDigest Assessment, SE, p. 689 LS Activity, p. 685; Quick Demo, Skill Assessment p. 685; Visual Learning, p. 687 Assessment, TWE, p. 689 LS Interpersonal Project, p. 688

684 685 Plants Plants BBIOIODDIGESTIGEST BIOIODIGESTIGEST BIOIODIGESTIGEST BBIOIODDIGESTIGEST Seed Plants Adapted for Cold Flowering Plants Flowers and Dry Climates Flowers are the organs of reproduction in Quick Demo A seed is a reproductive structure that con- The flowering plants, division Anthophyta, Assessment Conifers are common in anthophytes. Sepals enclose the flower bud and tains a sporophyte embryo and a food supply form the largest and most diverse group of plants cold or dry habitats through- protect it until it opens; petals, which are often Performance Have stu- Kinesthetic Bring to class enclosed in a protective coating. The food supply on Earth today. They provide much of the food out the world. Conifer needles brightly colored or perfumed, attract pollinators. dents collect branches or leaves of nourishes the young plant during the first stages eaten by humans. Anthophytes produce flowers and allow students to have a compact shape and a Inside the circle of petals are the pistil and stamens. of growth. Like spores, seeds can survive harsh and develop seeds enclosed in a fruit. local trees and use field guides to handle several varieties of thick, waxy covering that helps conditions. The seed develops into the sporophyte identify them. The lesson can be reduce evaporation and con- conifer cones. Include male generation of the plant. Seed plants include serve water. Conifer stems are Monocots and Dicots The pistil is the female reproductive organ. extended by trading botanical cones if available. Tell students conifers and flowering plants. covered with a thick layer of The Anthophytes are classified into two Inside the ovary at the base of the pistil are specimens with teachers in other the common name and/or Latin the ovules. Ovules contain the female game- bark that insulates the tissues classes: the monocotyledons and the dicoty- areas. L2 name of the tree each cone is Conifers inside. These adaptations ledons. Cotyledons, or “seed leaves,” are con- tophyte generation of the plant. Female from. Ask students to record Conifers, division Coniferophyta, produce enable conifers to carry on life tained in the seed along with the plant embryo. gametes—egg cells—form in each ovule. their observations of each seeds, usually in woody strobili called cones, and processes even when tempera- Monocots have a single seed leaf that absorbs Visual Learning P have needle-shaped or scale-like leaves. Conifer tures are below freezing. food for the embryo. The two seed leaves of Pollen species in their journals. L1 Visual-Spatial Explain to seeds are not enclosed in a fruit. Most conifers dicots store food for the embryo. Stigma Anther are evergreen plants, which means they bear students that monocots have leaves all year round. Pistil Style Stamen leaves with parallel veins and The leaves and branches of conifers Monocots (left) include grasses, Filament flower parts in multiples of three. are flexible. They bend under the orchids, and palms. Dicots Ovary P LS Dicots have leaves with netted Guest Speaker weight of snow and ice, allowing any (below) include many flower- buildup to slide off before it becomes ing trees and wildflowers. veins and flower parts in multi- Have a pharmacist or physi- heavy enough to break the branch. ples of four or five. Have students cian visit the class to discuss use these characteristics to clas- plants that are important in the LS VITALITAL STATISTICS sify photographs or cut flowers production of medicines. P Ovules brought into the classroom. Conifers Extend the lesson by having stu- Examples: Pine, spruce, fir, larch, yew, redwood, juniper. Sepals Numbers: 400 species. dents discuss the sizes and shapes Size range: Giant sequoias of central California, to 99 m Petals The stamen is the male of the flowers and their adapta- LS tall, the most massive organisms in the world; coast red- reproductive organ of a tions for pollination. L1 Seeds of conifers develop at the base woods of California, to 117 m, the tallest trees in the world. flower. Pollen grains con- CD-ROM of each woody scale of female cones. taining male gametes form inside the anther. Biology: The Dynamics of Life OCUS ON DAPTATIONS Animation: Life Cycle of a Pine FFOCUS ON AADAPTATIONS Exploration: Classifying Pines CD-ROM Vascular Plants The stems of most Disc 3 Moving from Water to Land CO plants contain vascular tissues made up of 2 Biology: The Dynamics tubelike, elongated cells through which water, Flower of Life ll plants probably evolved Nonvascular Plants Water and food, and other materials move from one part Flower stalk Animation: Water UptakeP in A from filamentous green In nonvascular plants, water and sugars of the plant to another. One reason vascular Roots algae that lived in the nutrient- nutrients must travel from one cell plants can grow larger than nonvascular plants Sugars ResourceResource rich waters of Earth’s ancient to another by the relatively slow is because vascular tissue is a much more effi- Exploration: Angiosperm ManagerManager oceans. An ocean-dwelling alga processes of osmosis and diffusion. cient method of internal transport than osmo- Disc 3 can absorb water and dissolved As a result, nonvascular plants are sis and diffusion. In addition, vascular tissues LS minerals directly into its cells. As limited to environments where Leaf H2O Reinforcement and Study include thickened fibers that can support taller land plants evolved, new struc- plenty of water is available. upright growth. Guide, pp. 109-110 L2 tures developed for absorbing and Roots Sugars to sink transporting water and minerals Content Mastery, An unbroken column of water from the soil to all the aerial parts pp. 121-124 L1 travels from the roots in xylem of the plant. Plants probably evolved tissues. Sugars formed by from filamentous photosynthesis travel around 686 green algae. the plant in phloem tissues. H2O 687

P MEETING INDIVIDUAL NEEDS BIOLOGYIOLOGY JOURNAL Visually Impaired Identifying and Classifying Kinesthetic As part of the Bellringer Plants P LS VIDEODISC demonstration, have students with Naturalist Have students collect pic- STV: Plants, What Is a Seed? visual impairments handle the plants. tures of different types of plants. Unit 4, Side 3, 13 min. 45 sec. Break off small parts for them to handle. They should identify the plants and classify What Is a Seed? (In its entirety) P LS Ask them to describe what they feel as them as vascular or nonvascular and non- partners write down their observations. seed or seed producing. L2 ELL Make sure students don’t injure them- !7,W=9LÇ" 686 selves by handling the plants. L1 687 LS P

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LS Plants Plants BBIOIODDIGESTIGEST BIOIODIGESTIGEST BIOIODIGESTIGEST BBIOIODDIGESTIGEST Pollen Fruit The phototropic Plant Responses response shown Assessment In seed plants, the sperm are enclosed in the Following fertilization, thick-coated pollen grains, which are the male the ovary develops into a Plants respond to changes in here is the result 3 Assess Knowledge Ask students gametophyte generation of the plant. Pollen fruit with seeds inside. their environment such as light, of increased cell to compare and contrast pollina- is one of the important adaptations that has Some flowering plants temperature, and water availabil- growth on the Check for Understanding ity. Chemicals called hormones side of the stem tion and fertilization in conifers enabled seed plants to live in a wide variety of develop fleshy fruits, land habitats. such as apples, melons, control some of these responses away from the Have students explain the differ- and flowering plants. In conifers, tomatoes, and squash. by increasing cell division and Stems light. ence between the terms in each of growing up pollen is carried by wind to the Pollinators Other flowering plants growth. the following word pairs. L2 female cone. In flowers, pollen may Flowers can be pollinated by wind, insects, develop dry fruits, such a. seed—spores as peanuts, almonds, also be transported by animals. In birds, and even bats. Some flowers have colorful b. vascular—nonvascular or sunflowers. Fruits Roots exhibit flowers, the pollen is carried to the or perfumed petals that attract pollinators. c. cone—fruit Flowers may also contain sweet nectar, as well as help protect seeds positive geotro- stigma. In both conifers and flowers, Maple tress produce pollen, which provides pollinators with food. until they are mature. pism. Stems show Roots d. monocot—dicot the pollen grows a tube through Fruits also help fruits with a winglike a negative geo- growing shape that can be which the sperm travels to reach the scatter seeds into tropic response. down Reteach ovary. In both, sperm and egg unite Plants that depend on the new habitats. carried long distances wind to carry pollen from by the breeze. P to form a zygote that develops into a Have students name plants that anther to stigma tend to are or produce structures, listed seed. have small, inconspicuous BIOIODIGESTIGEST ASSESSMENT in the word pairs of the Check flowers. The flowers of VITALITAL STATISTICS B D A Knowledge grasses and this alder are for Understanding. Ask them to pollinated by the wind. Flowering Plants Understanding Main Ideas 7. Mosses, ferns, and club mosses are alike explain why each plant is LSrepre- After students have observed Examples: Grasses, oaks, maples, palms, because they require ______. sentative of the term. L2 irises, orchids, roses, beans. 1. Which of the following is a Bryophyte? a. water for fertilization flowers and fruits from the same a. moss c. club moss Plants that depend on insects Numbers: 230 000 species (60 000 monocots; b. adaptations for conserving water plants, ask them to discuss which b. horsetail d. conifer for pollination may be brightly 170 000 dicots). c. insects for pollination Extension parts of the flower become which colored and fragrant. Pollen rubs Size range: A few millimeters to 75 m. 2. The term for a mature fern leaf d. warm, sunny habitats Linguistic Have students parts of the fruit, and to identify off on the bee that visits a flower is ______. 8. Lycophytes, sphenophytes, and conifero- research one plant division the parts of the flower that wither to feed on a. leaf c. frond phytes have specialized leaves that form away and do not form part of the nectar. When Pollen is carried to the stigma of a flower. The b. scale d. needle reproductive structures known as ______. of their choice and present a brief it moves pollen grain grows a tube down the style to the 3. Nonvascular plants would most likely be a. sori c. cones oral report to the class. L3 fruit. The ovary swells to become the P to another ovary. Two sperm travel down the tube. found growing ______. b. flowers d. strobili fruit. The ovule may be visible flower, some a. in sandy desert soil 9. Vascular plants do not include the . of the pollen ______around the seeds, as in apples. The b. on an ocean beach a. Lycophytes c. Sphenophytes may rub off Assessment sepals may be visible on the blossom c. on a snowy mountain slope b. Bryophytes d. Pterophytes onto the Pollen tube d. in a shady, moist environment Skill Have students pre- end of the fruit. Petals, pistil, and stigma. 10. Which plant group produces flowers and LS 4. Which plant group has leaves adapted for pare a chart that shows theP differ- stamen wither away. Ovary seeds enclosed in a fruit? life in cold environments? a. Anthophyta c. Pterophyta ent types of plants and their major Sperm nuclei a. Anthophyta c. Pterophyta b. Coniferophyta d. Lycophyta characteristics. L2 Visual Learning b. Sphenophyta d. Coniferophyta Ovule Linguistic Bring into the 5. Dicots have ______. Thinking Critically a. one cotyledon LS classroom several different 1. Compare the spore-bearing structures of Many plants b. two cotyledons fruits, including both dry and c. needlelike leaves ferns with the seed-bearing structures of 4 Close fleshy varieties. If possible, bring produce fruits conifers. that are eaten d. spores borne in cone-shaped strobili fruits that develop from some of by animals. 6. Reproductive structures of conifers are 2. Why do vascular plants have an adaptive Activity advantage over nonvascular plants? the flowers used in the above Egg nucleus ______. Have students prepareP questions activity. Have students examine and endosperm a. flowers c. fruits 3. Describe three ways in which seeds may be about the major characteristics of nucleus b. cones d. sori dispersed. the exterior of each fruit, then plants and write them on the cut it open to observe the In a process called double fertilization, one of chalkboard. Have the class discuss arrangement of seeds. Ask stu- the sperm fertilizes the egg and the other unites each question. LS dents to describe their observa- 688 with the endosperm nucleus. 689 tions in their journals. L1

PROJECT BIOIODIGESTIGEST ASSESSMENT Thinking Critically 3. Seeds may be blown away by the wind. 1. Ferns produce spores in sori on fronds. They may be carried by water when they Street-Tree Census Understanding Concepts fall in the ocean or in streams. They may CD-ROM Coni-fers develop seeds at the base of Interpersonal Have students 1. a 4. d 7. a 9. b also be transported by animals who eat Biology: The Dynamics of Life scalelike leaves that form cones. conduct a street-tree census 2. c 5. b 8. d 10. a the fruit and discard the seeds, or by ani- Animation: Double Fertilization 2. Vascular plants are not limited to moist in their community. They can analyze the 3. d 6. b mals who pass seeds through their diges- Animation: Fruit Formation environments because they do not have results of the census and submit a class tive systems and deposit them with their Exploration: Pollination to rely on osmosis and diffusion for P report to the community government droppings. Disc 3 transport of water and nutrients. Also, with suggestions on locations where addi- vascular tissue provides support so the tional trees could be planted. L3 plants can grow larger. 688 COOP LEARN 689 LS P

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