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Home , Gametangium

Plants,Fun gi,and the Colonizationof Land

Objectives

Introduction Explain the significanceof mycorrhizae to health. l7.l Compare the structure of multicellular and . Explain how plants are adapted to life on land. Plant Evolutionand Diversity 17.2 Explain how the first terrestrialplants evolved. Describe the structureof charophyceans and the plantscalled Coolcsonia. 17.3 Distinguishbetween , seedless vascular plants, gymnospenns, and angiosperms. 17.3 Describethe four key adaptationsfor life on land that evolvedin plants.

Alternation of Generations and Plant Life Cycles 17.4 Describe the alternation of generationslife cycle. Explain why this cycle appearsto have evolved independentlyin different $oups of plants. 17.5,17.6 Describe the key eventsof the moss and life cycles. 17.7 Explain how coal formed. 17.7 Describe the conditions in which the gymnospermsbecame dominant. 17.8 Describe the stagesof the pine tree life cycle. 17.9 Describe the parts of a flower and list their functions. t7.t0 Describe the stagesof the angiospermtree life cycle. t7.tl Describe examplesof adaptationsthat promote seed dispersal. 17.12 Describe the significanceof angiospermsto humans. 17.t3 Explain how flowers are adapted to attract pollinators. L7.14 Describe the human impact on plant diversity. Explain the significance of this loss for humanity. Fungi 17.15 Describethe importantroles of fungi in naturalsystems. Explain why the mutualistic relationshipbetween plants and fungi was vital to the movementof both groupsonto land. 17.16 Describethe main traitsof fungi. 17.17 Describethe most coilrmonlife cycle of fungi. 17.18 Describethe sffuctureand characteristics of lichens. 17.19 Explain how parasiticfungi harmplants and . 17.20 Describethe positiveecological and practical roles of fungi.

161 162 Instructor's Guide to Text and Media

KeyTerms mycorrhiza seed anther kingdomPlantae spore carpel cuticle pollination stigma stoma gymnospenn ovary vasculartissue angiosperm fruit xylem alternationofgenerations kingdomFungi phloem fossil fuel absorption gametangium hypha embryophyte mycelium charophycean grain dikaryoticphase sporangium sepal fruiting body petal mating type vascularplant stamen lichen

Word Roots bryo- : moss;-phyte : plant (bryophytes.'the mosses,liverworts, and hornworts;a groupof nonvascu- lar plants that inhabitthe land but lack many of the terrestrialadaptations of vascularplants) di- : two; -karyo = nucleus(dil

LectureOutline Introduction Plantsand Fungi-A Beneficial Partnership A. The lives of modern plants and fungi are intertwined. 1. We dependon plants and, indirectly, fungi for much of our food. 2. Plants are often harmedby fungi. 3. On the other hand, mycorrhizal fungi aid nearly all plants in the wild. Mycorrhizae are rootlike structuresmade of both fungi and plants. The fungi help plants obtain nutrients and water, and protect plant roots from parasites,in exchangefor food the plantsmake by photosynthesis(Figure 17.0). Preview:Mycorrhizae are also discussedin Module 32.11. 4. Modern agriculturalpractices, such as killing the parasiticfungi with fungicides, may disrupt mycorrhizal fungi, forcing the need for fertilizer. 5. Preview:This kind of dilemmaoften resultswhen humanstry to manipulatecom- plex naturalsystems (Chapter 38). B. Plantsand fungi evolved togetheras life movedonto land over 400 million years ago (mya).This observationis supportedby the earliestplant fossilshaving mycorrhizae. Chapter 17 Plants, Fungi, and the Colonization of l^and t63

Module 17.1 What is a plant? A. Review:In the two-kingdomsystem, Linnaeus classified algae as plants.In the five- kingdom system,algae are (Modules 15.14and 16.25). B. The definitionof plantsas multicellular,eukaryotic photosynthesizers also describes multicellular algae(Modules 16.23 and 16.24). C. Multicellular seaweeds,the most complex algae,are adaptedfor life in water,while plants are adaptedfor life on land (Figure L7.lA). For the former,the resources,includ- ing water,carbon dioxide, and minerals,are in direct contactwith their tissues,and wasteproducts can be washedaway. Water supportsand suspendsthe body of the alga. Holdfasts anchor the alga, and all other parts can be photosynthetic.Water provides a meansof dispersalfor gametesand offspring. D. Life on land imposesproblems. Water and nutrients are concentratedin the ground, while carbondioxide and light are most abundantabove the ground.Air provides no support againstthe force of gravity and will dry out reproductivecells. E. Adaptationsto a tenestrialenvironment in plants include the following: l. Discreteorgans: roots, stems,leaves, and gametangiaspecialized for anchorageand absorption,support, photosynthesis, and reproduction,respectively. 2. Mycorrhizalfungi to increasethe efficiency of absorptionof their roots. 3. A vascularnetwork to move food (phloem) and water (xylem) amongthe pans (Figure17.1B). 4. A cuticle on leavesand stemsto help retain water. 5. Dependencyon wind or animalcarriers to dispersemale (contained in pollen) and offspring. 6. Offspring are kept moist by developing within the female gametangium.

I. Plant Evolution and Divercity Module 17.2 Plantsevolved from greenalgae called charophyceans' A. Plants and green algaehave a number of homologousfeatures, such as identical photo- syntheticpigments, food storagemolecules, cell walls, and mechanismsof cell division (Modules 16.23and 16.24\. B. Plants may have evolvedfrom greenalgae about 500 mya. The ancestoris not known, but analysisof nucleic acid sequences,cell structure, and biochemistryindicate that a group of greenalgae, the charophyceans(Figure 17.2A,a simplecharophycean), and plants shareda commonancestor (Figure 17.2B.,a complexcharophycean.) C. Early plantsthrived on moist shorelineswhere spacewas essentiallylimitless, sunlight was abundant,and where there may not have been any herbivorousanimals. D. Among the earliestplant fossils is Coolcsonia,which have been found in strata datedto 408 mya. This plant had branched,upright, photosyntheticstems and sporesacs (spo- rangia) but lacked leaves(Figure 17.2C). E. Plants more complex than Cooksoniaare known to have been abundant=400 mya. Like Coolcsoniathey lacked leaves,but they had more complex sporangiaand were more firmly anchoredto the soil. F. A large numberand diversityof plantswith well-developedleaves and roots were pres- ent by 375 mya. t@ Instructor'sGuide to Textand Media

Module L7.3 Plant diversityprovides clues to the evolutionaryhistory of the plant kingdom. A. Plant phylogeny showsbranching of severalplant lineages,reflecting major evolutionary steps.These are previewedhere, and detailsare addedin the modulesthat follow (Figure 17.3A). B. Two lineagesof plants arose,most likely from charophyceans,=400 mya. One of these lineagesgave rise to modernbryophytes. The otherlineage gave rise to vascularplants. C. Like other plants, bryophytes have a cuticle and embryosthat develop within gametan- gia. However,many bryophyteslack vasculartissue for waterconduction and internal support.Like their algal ancestors,bryophytes have flagellated spenn and dependon water for reproduction(Figure 17.38). D. Vascular plants have xylem and phloem that transportwater and nutrients and provide support (Figure 17.3C).In addition,these plants have embryonic development within gametangia. E. About 360 mya, vascularplants split into two lineages.One of theselineages gave rise to seedlessplants and the other gaverise to seedplants. are a modern exampleof a seedlessvascular plant and use a haploid spore for reproduction. The leaves(fronds) developfrom stemsthat grow along the ground (Figure 17.3C).Ferns are found in shadytemperate forests and are most diverse in the tropics. G. Seedplants makeup =90Voof all living plant species.Adaptations responsible for the successof this group include seedsthat provide the embryonicplant with a protective coating and a food supply.These plants also produce pollen, vehicles that transfernon- flagellated spenn to the female parts of plants. H. The earliest seedplants to appearwere the gJrmnosperms(naked seed). The nameof theseplants is basedon their seedsnot beingcontained within a fruit. , along with seedlessplants, were dominantfor over 200 million years.The largestliving group of gymnospermsare the . L Flowering plants (angiosperms) evolvedfrom the seedplant line =130 mya. Flowers increasethe efficiency of pollination and developinto fruils that protect seedsand increasethe efficiencyof seeddispersal. The majority of modernplant speciesare angiosperms. Preview: Angiospermsffucture is discussedin detail in Chapter31.

II. Alternation of Generations and Plant Life Cycles Module 17.4 Haploid and diploid generationsalternate in plant life cycles. A. Review: Ulva hfe cycle (Figure 16.24C);human life cycle(Figure 8.13). B. Plant life cyclesalternate between multicellular, diploid (2n) andhaploid (1n) adults, unlike animals that are diploid as adults and producesingle-celled haploid gametes (Figure 17.4). c. Sporophytesgrow from diploid zygotesand producespores by . D. Gametophytesgrow from haploid sporesand producegametes by mitosis. E. Alternation of generations provides two chancesto producelarge numbersof offspring, zygotes,and spores. F. Major changesfrom the algal life cycle that occurredduring the evolution of plants were the changein dominancefrom the gametophyteto the sporophyte,the changein dependencyof sporophyteson gametophytesto the oppositedependency, and the loss of flagellatedsperm except in mossesand ferns. Chapter 17 Ptnnts, Fungi, and the Colonization of l-and 165

NOTE: Comparethe mosses(dominant , semiparasitic sporophytes, flagel- lated sperm)to the conifersor floweringplants (dominant sporophytes, semiparasitic, reducedgametoPhytes, Pollen).

Module 17.5 Mosseshave a dominantgametophyte' A. The greengrowth we seeconsists mostly of gametophytes(Figure 17.3B). NOTE: Adult gametophytesconsist of nonvascularstems and leavesand threadlike holdfasts.For water and minerals, they dependon rain or on water flowing along the stem from the ground surface. B. Gametophytesproduce sperm and eggsin gametangia(Figure 17.5). C. Flagellatedspenn require a film of waterin which to swim from malegametangium to female gametangium. D. The zygote remainsin the female gametangiumand developsinto the sporophyte. E. Meiosis occursin the sporangiumand producesspores. F. Sporesare releasedand later developinto gametophytesby mitosis. NOTE: Adult sporophyteslose their chlorophyll and becomemore dependenton the female gametophytes.The sporangiaare adaptedto dispersingspores by meansof mov- able teeth around the sporangiumopening, on wet/dry cycles'

Module 17.6 Ferns, like most plants, have a dominantsporophyte' A. The fern fronds we seeare sporophytes. NOTE: Ferns haveunderground stems with small roots, and all parts are vascularized. The fronds are the principal organsof photosynthesis. B. Gametophytesproduce flagellated sperm and eggs (like mosses)(Figure 17.6). C. Like mosses,fern zygotesremain in the femalegametangium and developinto adult sporophytes.Eventually the sporophytestake over. D. Sporangiain clusterson the frond's undersideproduce haploid spores by meiosis. NOTE: Fern sporangiahave a unique mechanismto releasetheir spores.As the sporan- "back" gia dry out, thick-walled cells along the of the sporangiumpull the thin-walled ifront" cells into tension.In a fraction of a second,the front cells rupture, scatteringthe sporesinto the air. E. Sporesare dispersedby wind and grow into small, heart-shapedgametophytes by mitosis. F. Today, about957o of all plants have a dominantsporophyte generation. "coal Module 17.7 Seedlessplants formed vast forests." A. During the Carboniferousperiod (=285-360 mya), vast forestsgrew in tropical, swampy areasover what is now Eurasiaand North America' B. The forestsincluded dominant lycopods, horsetails (both seedlessplants more primitive than ferns),and treeferns (Figure 17.7). C. The compressedremains of theseforests survive as depositsof coal and other fossil fuels. D. At the end of the Carboniferousperiod, the climate turned colder and drier, providing the conditions for further plant evolution.The evolutionof pollen was key to the adap- tation of seedPlants to dry land. 166 Instructor's Guideto Tbxtand Media

E. The mostsuccessful of the early seedplants were the gymnospenns.They grew along- sideseedless plants in Carboniferousswamps. Conifers survivedthe drying of these swampsand remain the dominanttype of gymnospenn. F. Gymnospermshave had a wide distributionfor =250 million years. Conifers are the most successfulof severalgroups of gymnospermsbecause they are adaptedto harsh winter climates.They readily shedsnow, their needlesresist drying, and sincethey do l not shedtheir leavesthey are able to start photosynthesizingas soon as the growing seasonbegins.

Module 17.8 A pine tree is a sporophytewith tiny gametophytesin its cones. A. Conesare a significantadaptation to land, protectingall reproductivestructures: sporan- gia, microscopicgametophytes, and zygotes. B. Femalecones are larger.Scales bear a pair of (sporangiawith a covering,or integument).Within the ovule, one of the four products of meiosis developsinto a tiny, multicellular,"female" . C. Male conesare smaller,and scalesbear many sporangiathat make sporesby meiosis. Sporesdevelop into tiny male gametophytes(pollen grains), each consisting of a few cells. Pollen grains housethe cells that will develop into sperm. NOTE: The particular pollen grains in Figure 17.8 are typical of the pine family: The "cells" cenfrd cell and cells within it composethe gametophyte.The two lateral are outgrowthsof the cell wall that function as floats. D. Pollen is dispersedby wind. Pollination occurs when a pollen grain lands near an ovule and growsinto it. E. Meiosis occursin the ovule where a haploid spore cell begins to develop into the femalegametophyte. Months later, a few of the female gametophyte'scells inside the ovule function as eggs.The pollen tube delivers a male gametophyte'snucleus (func- tioning as a nonflagellatedsperm) to fertilize an egg. F. The zygotedevelops into the embryonic sporophyte,and the remaining ovule develops into the other parts of the seed(the integumentbecomes the seed coat, and the female gametophytebecomes a food supply). G. Seeddispersal is by wind or . H. Under favorableconditions, the seedgerminates and the embryo grows into a tree.

Modute 17.9 The flower is the centerpieceof angiospermreproduction. Preview:The life cycle of the floweringplant (Modules31.9-31.15). A. Flowersexpose an angiosperm'ssexual parts and are the sites for pollination and fertil- ization(Figure 17.9A). B. Flowersare short stemswith the following modified leaves:sepals, to protect flower buds;petals, to atffact animal pollinators; stamens, the male parts (holding the anthers, in which pollen develops);carpels, the female parts (consisting of sticky stigma to trap pollen; and the oyary, which bearsovules and later developsinto fruit) (Figure 17.98).

Module 17.10 The angiospermplant is a sporophytewith gametophytesin its flowers (Figure17.10). A. Review:Gymnosperm life cycle (Figure 17.8). B. Flowersprotect all microscopicreproductive structures: sporangia, male and female gametophytes,and zygotes. Chapter 17 Plants, Fungi, and the Colonization of Innd 167

C. Meiosisin the anthersleads to haploid sporesthat undergomitosis and developinto the malegametophytes (pollen grains). D. Meiosisin the ovulesleads to haploid sporesthat undergomitosis and developinto the femalegametophytes, each of which producesffi eEE,inside the ovules. E. Pollenis dispersedby eitherwind or insects.Pollination occurswhen a pollen grain landson the stigma. F. The pollen grows into the ovary and delivers one nucleus (again functioning as a non- flagellatedsperm) to the egg nucleusin the ovule. Fertilizationusually occurs within 12 hoursafter pollination. G. Following fertilization, the zygote developsinto the embryonic sporophytein the seed, and the ovary developsinto the fruit. H. Seeddispersal is alsoby wind or animal and is aided by the envelopingfruit. I. Under favorableconditions, the seed germinatesand the embryo developsinto a mature sporophyte. J. Preview:Further details about the life cycle, includingthe uniqueadap- tationof doublefertilization, are coveredin Modules 31.9-31.15.

Module 17.11The structureof a fruit reflectsits function in seeddispersal. A. Fruits developfrom ovariesand ripen quickly, within one growing season. B. Somefruits are adaptedfor wind dispersalof seeds(Figure 17.11A). C. Othersare adaptedto hitch aride on animals(Figure 17.118). D. Fleshy,edible fruits are attractiveto animals as food. Seedsof thesefruits usually pass unharmedthrough the animal's digestive tract and are deposited,with fertilizer, far from the parentplant (Figurel7.llc).

Module 17.12Connection: Agriculture is basedalmost entirely on angiosperms. A. Gymnospermssupply almost all our lumber and paper, but food comesfrom angiosperms. B. Angiospennsare also usedfor fiber, medication, perfirmes, and as a sourceof fine hardwoods. C. Agriculture beganwhen humansdecided to cultivate grains in an effort to confrol food supplies.Selective breeding produced bener plants and today genetic engineersare developingnew and improvedplants.

Module 17.13 Interactionswith animalshave profoundly influenced angiospermevolution. Preview: Coevolution(Module 36.3). A. Most floweringplants depend on insects,birds, or mammalsfor pollinationand seed dispersal. B. Most land animalsdepend on floweringplants for food. C. Pollenand nectarprovide food for pollinators.Bees are one of the most highly co- evolvedgroups of pollinators(Figure 17.13A). D. Flowersthat arepollinated by birds are usually pink or red (Figure 17.138). E. Flowersthat arepollinated at night by bats or moths are usuallylarge and light-colored (Figure17.13C). F. Thesemutual dependencieshave been favored by natural selection. r68 Instructor's Gui"deto Tbxt and Media

Module 11.14 Cowrection:Plant diversityis a nonrenewableresource. A. Plant biodiversity is being reducedat an unprecedentedrate. The majority of plant geneticdiversity is found in the rain forestsof the world. B. The loss of plants is harmful in a varietyof ways: 1. Tlventy-fivepercent of all prescriptionmedicine comes from plantsand only 5000 of the more than 320,000plant specieshave been researched as possiblemedicines. 2. Animals are perishingalong with the plants. 3. Plant loss reducesair and water quality. c. Approximately 50 million acresof forest are clearedevery year.In an effort to reduce plant diversity loss, scientistshave joined with the UN and an organizationcalled the All SpeciesFoundation in an effort to catalogall speciesin the next 25 years. D. Efforts are also under way to learn how to harvesttimber in an environmentallysound manner.

III. Fungi Module 17.15 Fungi and plants movedonto land together. A. Revian:Mycorrhizae helpedmake colonizationof land possible(Opening Essay, Figure 17.0). B. Fungi are heterotrophic and require externalsources of food molecules.They likely evolved to terrestrial habitatsfrom aquaticancestors, joining their food supply, which were early plants on land. c. Fungi are found in both terrestrial and aquaticenvironments. D. Many fungi are parasitesof plants(Figure 17.15A). Preview:Some fungi and plantshave a mutualisticrelationship (Module 32.11). E. A few fungi have unique adaptationsthat enablethem to trap animalsfor food (Figure17.158). F. A major role of fungi is the decompositionof deadorganisms, particularly plants, and their organic molecular remains. Somefungi can break down other organic materials, includingresidues of pesticidesand cancer-causingchemicals (Figure 17.15C).

Module 17.16 Fungi absorb food after digestingit outsidetheir bodies. A. The kingdom Fungi includes heterotrophiceukaryotes that digest their food externally and absorbthe resulting small moleculesas nutrients.Other characteristics include: cell walls of chitin, spore production, and the absenceof motile stages.Fungi are grouped in their own kingdom. They differ from plants,with which they were once classified, becausethey cannot make food by photosynthesis,and in the details of their cellular and molecular structure. B. Fungi are usually multicellular,but their bodies(mycelia) are composedof extensive networks of hyphae (filamentouscell-like units). Hyphaemay be branched,may be a ,or may be divided into cell-likecompartments (Figure 17.164, D). C. The hyphaeof the mycelium extendrapidly into the food source,developing a huge surfacearea from which digestiveenzymes are secretedand through which the digested food is absorbed.A large mycelium can add as much as a kilometer of hyphae each day (Figure17.168). D. Somefungi produce mushrooms,external reproductive bodies composed of packed hyphae(Figure l7.l6c). Chapter17 Plants, Fungi, and the Colonizationof Land 169

Module 17.17 Many fungi havethree distinct phasesin their life cycle. A. The phasesof mushroom-producingfungi and their relativesare charactenzedby a dikaryotic phase(Figure 17.17). B. Fertilizationof one nucleusin a dikaryotic pair with anotherin the mushroom(fruiting body) producesdiploid zygotes.These are held in terminal cells of the hyphaein the mushroom.Meiosis of this zygoteproduces the haploid nuclei that form spores. C. Haploid sporesare shedfrom the fruiting body, are wind-dispersed(or dispersedby water or animals),and developinto haploid mycelia.Two compatible,haploid mycelia can fuse to form a dikaryoticmycelium. D. The dikaryoticmycelium maintains the compatible(and geneticallydifferent) nuclei, pairedbut separate.This phaseis dominant in the life of the ,often lastingfor many yearsas it continuesto grow into its food source.Dikaryotic hyphae also make up the tissuesof the mushroomsproduced by this myceliumperiodically. "humongous NOTE: The fungus" in Michigan, a speciesof Armillaria, is estimatedto occupy30 acresand be 1500years old. However,the myceliumof Armillaria is a uniqueexception among mushroom-producing fungi. It is diploid for most of its life. An evenlarger fungus was recentlyfound in Oregonthat is spreadout over 22U].acres. E. Somefungi arc very simple.Yeasts are single-celledand mostly reproduceby mitotic cell division. NOTE: The term yeast refers to a growth form and ecological habitat preference(plant saps),not to a taxonomiccategory. There are many typesof yeasts,related by reduction in form to severalnot closelyrelated fungi. Many yeastsexhibit sexualstages.

Module 17.18 Lichensconsist of fungi living mutualisticallywith photosyntheticorganisms. A. Lichens are associationsof millions of green algaeor cyanobacteriaheld in a tangled networkof fungalhyphae (Figure 17.18B). B. The fungusreceives food from the photosynthesisof its partner. C. The alga or cyanobacteriumreceives housing, water, and the mineralstrapped by the hyphal network. D. Alt lichen fungi and most lichen algaeand cyanobacteriacannot grow independently. The relationshipis so completethat they are classifiedtogether as a singlespecies. E. Asexualreproduction of the fungusand alga togetheris advantageous;dispersal of both partnersoccurs, and they can immediatelyreestablish the lichen. F. Lichens are able to survive in habitats where neither partner (nor any other multicellular organism)could grow alone(Figure 17.184). However,they are highly susceptibleto airbornepollutants. G. Lichens play important ecological roles in soil formation on rock surfacesand as food for animals(Figure 17.18C). NOTE: Cyanobacterium-containinglichens fix nitrogen and play important roles in the nitrogencycle (Module 36.16). H. Somelichens are thousandsof yearsold.

Module 17.19 Connection:Parasitic fungi harm plants and animals. A. Of the 100,000species of known fungi, about one-thirdare mutualisticin mycorrhizae and lichens,one-third are decomposers,and one-thirdare parasites. B. Parasiticfungi are the most seriousplant pests.Particularly dangerous are nonnative parasites,such as the fungusthat causesDutch elm disease(Figure l7.l9A). Instructor's Guide to Tbxtand Media

C. Someparasitic fungi attackdeveloping seeds and fruits of grains(Figure I7.l9B). D. Fungi causea few diseasesin humans.Flour madefrom grain infestedwith ergotscan causegangrene and nervoussystem disorders (17.19C). LSD is one of the toxins that has been isolatedfrom ergots.Some infections of lung tissuecan be fatal, particularly in people weakenedby other diseases.Less serious are the fungal infectionsof the outer layers of the skin known as ringwormand athlete'sfoot. Fortunately,fungicidal ointmentscan control most of thesefungal parasites. E. Yeastinfections of the vaginaare usuallycaused by somechemical, microbial, or immunologic changein the body and are classifiedas opportunisticinfections. This type of infection is on the rise due to the emergenceof AIDS, which suppressesthe immune system.

Module 17.20 Connection:Fungi haveenormous ecological and practicalimpact. A. Mushrooms and other fungi are eaten. B. Certain molds lend distinctive flavors and textures to foods such as Roquefort and blue cheese (Figure I7.2OA), and underground truffles (which also are important mycorrhizal tungi). c. Different strains of one kind of yeastare usedin baking, brewing, and winemaking. D. Somefungi are importantcommercial sources for antibiotics(Figure l7.2OB). E. There is evidencethat fungi evolvedfrom the sameprotistan lineage that gave rise to animals.

ClassActivities 1. Haveyour studentscollect andclassify examples of the differentplant and fungal speciesfound in the areain which they live. (It's a classic,but it's still a goodway of familiarizingyour studentswith the diversityof life.) 2. A considerablenumber of wild, cultivated,and cultured fungi arenow availablein many marketsin the United States,both in fresh anddried condition,depending on the seasonand local availability of mushroomfarms or proper habitat.Bring in examplesto stimulatediscussion and interestin the topic "plant" of fungi. Point out that the mushroomyou seeis like the appleof an appleftee: the (mycelium) that producesthe mushroomis invisible to the nakedeye. The myceliumof the most commonly avail- able mushroom,Agaricus campestris,is a litter decomposerof compostedstraw. Oyster mushrooms and the Japanesemushroom, shiitake, are quite cornmonin bettermarkets and are both litter decom- posersof wood (but can be grown on artificial logs madeof sawdust).In season,you may be able to find goldenchanterelles (the mycelium of which forms myconhizae,so theseare not domesticated), truffles (very expensiveand alsomycorrhizal), or morels(a recent,secret process allows theseto be cultued). The moldy cheeses(Brie, Camembert,and blue); wine,beer, and soy saucebottles; and a loaf of breadcan also be usedas propsto shessthe diversityof our dependencyon fungi for food. In health- food storesyou may also be ableto find tempeh,a soybeanproduct fermented with Rhizoptrsmold. 3. Almost everyregion of the United Stateshas at leastone seriousplant-pathogenic fungus. Contact your local agricultural extensionoffice to obtain detailsabout the identity of thesefungi, and their classification,hosts, and controls.Featuring a specificrepresentative will help clarify the generalchar- acteristicsof the kingdom as a whole, particularly the reproductiveadvantage of producing sporesand the easewith which their hyphaeenter plant tissues. In presentingspecial information on local para- sitic fungi, be sure to remind your studentsthat the majority of fungal speciesare beneficial to humans,either in their roles asrecyclers or mycorrhizaformers. Chapter 17 Plants, Fungi, and the Colonization of Land t7l

TransparencyAcetates Figure17.1A Comparinga multicellulargreen alga and a plant Figure 17.2C Cooksonia,one of the earliestvascular land plants (fossil at left) Figure 17.3A Somehighlights of plantevolution Figure17.4 Haploid anddiploid generations(Layer 1) Figure 17.4 Haploid anddiploid generations(Layer 2) Figure 17.4 Haploid anddiploid generations(Layer 3) Figure 17.5 Life cycle of a moss Figure17.6 Life cycle of a fern Figure17.8 Life cycle of a pine ffee Figure 17.98 The parts of a flower Figure17.10 Life cycle of an angiosperm Table17.14 A samplingof medicinesderived from plants Figure 17.164 A mycelium,made of numeroushyphae (in this case,consisting of chainsof cells) Figure17.17 Life cycle of a mushroom

Media

See the beginning of this book for a complete description of all media available for instructors and stu- dents. Animations and videos are available in the Campbell Image Presentation Library. Media Activities and Thinking as a Scientist investigations are available on the student CD-ROM and web site.

Animations and Videos File Name Flowering Plant Life Cycle Time-Lapse Video 17-0 1 -PlantTimelapseVideo-B.mov Flowering Plant Life Cycle Time-Lapse Video 17-0 1 -PlantTimelapseVideo-S.mov Moss Life Cycle Animation I 7-05-MosslifeCycleAnim.mov Fern Life Cycle Animation I 7-06-FernlifeCycleAnim. mov Pine Life Cycle Animation 17-08-PinelifeCycleAnim.mov FlowerBlooming Time-LapseVideo 17-09-FlwrTimelapseVideo-B.mov Flower Blooming Time-LapseVideo I 7-09-FlwrTimeLapseVideo-S.mov Bee Pollinating Video I 7-1 3A-BeePollinatorVideo-B.mov Bee Pollinating Video I 7-1 3A-BeePollinatorVideo-S.mov Bat Pollinating Agave Plant Video I 7-1 3C-BatPollinatorVideo-B.mov Bat Pollinating Agave Plant Video I 7-1 3C-BatPollinatorVideo-S.mov AllomycesZoospore Release Video 17- I 7-AllomyZoosporeVideo-S.mov Phlyctochytrium 7-oosporeRelease Video 17- I 7-PhlycZoosporeVideo-B.mov Phlyctochytrtum 7-oosporeRelease Video 17- 17-Phly cZoosporeVideo- S. mov Saprole g nia OogoniumVideo I 7-1 7-SaproOogoniumVideo-B.mov Sap ro Ie gnia OogoniumVideo I 7-I 7-SaproOogoniumVideo-S.mov -l

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SaprolegniaZoospore Release Video 17- I 7-SaproZoosporeVideo-B.mov SaprolegniaZoospore Release Video I 7- 17-SaproZoosporeVideo-S.mov FungusLife CycleAnimation 17 - 17 -FunguslifeCycleAnim.mov

Activities and Thinking as a Scientist ModuleNumber Web/CDActivity l7A: TbnestrialAdaptations of Plants t7.r Web/CDActivity l7B: Highlightsof Plant Evolution r7.3 Web/CDActivity l7C: MossLife Cycle 17.5 Web/CDActivity I7D: Fern Life Cycle t7.6 Web/CDThinking as a Scientist:What Are the Dffirent Stages of a FernLife Cycle? 17.6 Web/CDActivity t7E: Pine Lift Cycle 17.8 Web/CDActivity I7F: AngiospermLifu Cycle 17.10 Web/CDActivity I7G; Connection:Madagascar and the Biodiversin Crisis 17.t4 Web/CDThinking asa Scientist:How Are Treesldentified by Theirlzaves? 17.14 Web/CDActivity l7H: FungalReproduction and Nutrition 17.16 Web/CDActivity 171:Fungal Life Cycles 17.17 Web/CDThinking as a Scientist;How Does the Fungus PilobolusSucceed as a Decomposer? 17.17