lesson 7: plant adaptations - · pdf filelesson 7: plant adaptations level one ... , the...

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LESSON 7: PLANT ADAPTATIONS

LEVEL ONE

Lifeisseldomideal.Wealllivewithsituationsthataredifficultforusinsomeway.Somepeoplefacesevereproblemssuchasnotbeingabletofindenoughfoodorcleanwater,livinginextremelyhotorcoldclimates,orhavingtodealwithachronicillness.Othersofuslivewithmilderlimitationshavingtodowithourage,oursize,ourfamilysituation,theneighborhoodwherewelive,theworkourparentsdo,thepersonalitiesofoursiblings,andsoon. Wedon’tthinkofplantsashavingthesameproblemsthatwedo,buttoalargeextent,theyreallydo.Theycanexperiencemalnutrition,extremetemperatures,unfriendlyneighbors,competitionforterritory,“parents”whoovershadowthem,“siblings”whoaremoreorlesssuccessfulthantheyare,chronicandacuteillnesses,andproblemsduetoaging.Obviously,theycan’tthinkabouttheirproblemslikewecan.Alloftheirresponsescomenotfromtheirbrains(whichtheydon’thave)butfromtheirpre-programmedDNAthat allows them to adapt and survive.

Let’stakealookattwoofthemostbasicproblemsaplantmightface.Wecouldintroducetheseproblemsasasilly“WouldYouRather...?”question.Inthe“WouldYouRather...?”game,playersareforcedtochoosebetweentwobadoptions.Forexample,“Wouldyouratherbetrappedinouterspaceoratthebottomoftheocean?”Nomatterwhichyouchoose,theoutcomewillnotbegood.Youmustchoosewhatyoufeeltobe“thelesseroftwoevils,”andthenexplainyourchoice.Thegameisintendedtoencourageinterestingdiscussionsandhopefullybringsomelaughteralongtheway.Ifplantswereplayingthisgame,oneofthemcouldaskthisquestion:“Wouldyouratherhavealmostnowateratall,orsomuchwaterthatyouaredrowninginit?”

Assumingthataplanthadabrainandcouldthinkaboutthisquestion,itwouldpondertheconsequencesofeachoption.Nothavingenoughwaterwouldmeanthatastranspirationoccurred,therewouldbenowaytoreplacethewaterlostthroughtheleaves.Theplantwoulddryoutandprobablydie.Beingimmersedinwaterwouldmeanthatthestomata(holes)intheleaveswouldbefilledwithliquidwater,preventingtheplantfrom“breathing,”causingtheplanttodie.Toomuchwatermightalsoencouragethegrowthofharmfulbacteria.Sowhichoptionisworse?It’slikechoosingbetweendyingofthirstanddrowning.Twobadoptions!

Someplantswoulddefinitelychoosethe“toolittlewater”option.Infact,theyliveoutthatscenarioeverydayandmangetosurvive.Desertplantshavespecialadaptationsthatallowthemtoliveinplacesthatgetlessthan10inches(25cm)ofrainayear.Indeserts,rainisoftenseasonal,andmonthscangobywithnorainatall.Howisitpossibleforaplanttosurvivethatlongwithoutwater?Gardenplantsstartwiltingiftheydon’tgetraineveryweek. Anormalplantgrowinginaplacewithadequaterainfallhasaconstantflowofwatergoinginthroughitsroots,upthroughitsstems,andoutthroughitsleaves.(Remember,thebeginningofthisprocessisactuallythe“outthroughtheleaves”part.Thelossofwaterintheleavescauseswatertoflowupthroughthestems,andfinallycomeinthroughtheroots.)Ifthereisnotaconstantsourceofwateravailable,thismodeoflivingdoesn’twork.Whatchangeswouldhavetobemadetoaplant’sanatomy in order to prepare it for life in a desert?

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LEAVES:Thisiswherethewaterlossproblemstarts.Thatpeskytranspirationprocessisconstantlyallowingwatermoleculestogoflyingoffintotheatmosphere.Canthisbeprevented?Couldwejustgetridoftheleaves?Maybe,butleavesarewherephotosynthesisoccurs,sotheplantswouldstarvewithoutphotosynthesis.Ifaplantdidnothaveleaves,itwouldhavetohavephotosynthesisoccurringsomewhereelse.Ormaybewecouldjustreducethesizeoftheleavesinsteadofgettingridofthemaltogether.Smallerleaveswouldmeanlesswaterloss.

STEMS:Whatchangescouldbemadetothestems?Couldphotosynthesisoccurhere?Couldthestemsbeadaptedforwaterstorageinsteadofsimplyholdingtubesforwatertransport?Ifso,thestemsmighthavetobecomeverylargeattimes.

ROOTS:Isthereanywaytomakerootsmoreefficientatgatheringwater?Shouldtherootsgodeeper?Orwoulditbebettertokeepthemshallowandnearthesurfacesothattheycanquicklysoakuprainwhenitcomes?Wouldhavingmoretinyroothairshelp?

Themostfamousofalldesertplantsisthecactus,ofcourse.Cactusplantslookliketheyhavenoleaves.Technically,theirsharpspinesareactuallyleaves,buttheseleaves are so thin that they lose almost no water at all. We saw a similar adaptation in pine trees. Pine needles are actuallyverythinleaves.However,sincepineneedlesaregreen,itiseasiertothinkofthemasleaves.Cactusspinesjustdon’tseemlikeleaves,butbotanistsassureusthatspinesareindeedhighlyadaptedleaves. Whatcouldpossiblybethepurposeofaleafthatcanhardly do photosynthesis and doesn’t initiate transpiration? Whatarecactusspinesgoodfor?Themainthingtheydoishurtlikecrazyifyougettheminyourskin.Sharpspineshelptoprotectcactifromthirstydesertanimalswhomightwanttoquenchtheirthirstwithabigbiteofjuicycactus

stem.Somebotaniststhinkthespinesmightalsohelptocollectwateratnight.Littledropletsofdewformonthespines.Thesedropletsrundownthespinestowardthestems,thentheyflowdownthestems,endingupatthebaseoftheplantwheretherootsnearthesurfacecanabsorbthemoisturequicklybeforethesuncomesup.

Thebodyofacactusistechnicallyastem.Mostcactiaregreen(oratleastgreen-ish),whichtellsyouthatthesebulkystemscontainchlorophyll.Whereverthereischlorophyll,photosynthesisisoccurring.Cactimustuseadaptedformsofphotosynthesis,however.Regularphotosynthesisrequiresaconstantsupplyofwaterandcarbondioxidefromtheair.The“downside”ofnothavingregularleavesisthatyoucan’tuseregularphotosynthesis.Thetypesofphotosynthesisdesertplantsusearecalled“C4”and“CAM.”(Regularphotosynthesisisknownas“C3”sinceitproduces3-carbonsugars.C4produces4-carbonsugars.“CAM”isanabbreviationforagruesomelycomplicatedwordthatevenscientistsdon’tliketousebecauseit’stoolong.Theyjustsay“CAM.”) Cactusstemshavetheabilitytostorealotofwater—enoughwatertokeepthecactusaliveduringdryseasonsthatlastformanymonths.Thebodyofacactususuallylookslikeitismadeof“pleats”thatgoinandout.Thisshapeallowsforeasyexpansionandcontractionwithoutanydisruptionoftherootsatthebaseoftheplant.Therootsystemofacactusisoftenveryshallowand

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extendsoutwardfromtheplantquiteadistance.Whenraincomes,thecactushasthousandsofroothairswaitingandreadyrightnearthesurface.Largecacticantakeinover100gallons(400liters)duringasinglerainstorm. Afewtypesofcactihaveverylongtaprootsinadditiontolotsofsurfaceroots.Thelongcentraltaprootcanbetwiceaslongasthebody(stem)ofthecactus.Thisdeeprootcanstorealotof water. Cactusstemshaveastructurethatotherplantsdonothave:bumpscalledareoles.Botanistsguessthatareolesaremostcloselyrelatedtothebranchesofregularplants.Itisfromtheareolesthatbothspinesandflowersgrow. Onelastimportantcactussurvivalstrategyistogrowslowly.Cactidon’tneedtobeinanyhurry.Growthtakesenergy.Aplant’senergycomesfromsugarsmadeduringphotosynthesis.Desertplantsarealreadyatadisadvantagewhenitcomestophotosynthesisbecausetheyhavetokeeptheirstomatashutalldaytopreventlossofmoisture.Growingslowlyreducestheneedforsugar.

Cactiarenottheonlytypeofplantsthatcansurviveindryclimates.Plantscalledsucculentsaresimilartocactiinmanyways,thoughtheyhaveactualleaves,notspines.Theleavesofsucculentplantsfeelthickand“juicy.”Thestemsareoftenverythickandcanstorewater.Somesucculentshavestemsandleavesthatarefilledwithagooeysubstancecalledmucilage (mew-sell-ahj).Themucilageactslikeaspongeandholdswater.Acommonsucculentplantthatmanypeoplerecognizeisthealoeveraplant.Somepeoplecallitthe“burnplant”becauseyoucanbreakopentheleavesandusethemucilagetosootheburnedskin.Themucilagemayfeelslimyandweird,butitdoesmakeyourskinfeelbetter.

Succulentleavesfeelliketheyarecoveredinawaxysubstance.Thisisbecausetheyare coveredinawaxysubstance.Wemetthiswaxysubstancebackinlessonfivewhensawthecrosssectionofaleaf.Thethintoplayerwascalledthecuticle.Allleaveshaveatleastatinybitofcuticle,butsucculentleaveshavealotofit.Cuticleisfairlywaterproof,soitkeepsmoisturefromgettingoutof(orgoinginto)theleaf. Anothercharacteristicofsucculentleavesisareducednumberofstomata.Thoselittlestomataholesarewhereairandmoisturegetinandoutofaleaf,soifyouhavefewerholesyouhavelessofaproblemwithwatermoleculesescaping.Succulentshavefewerstomatathanregularplants.Also,succulentstendtoclosetheirstomataduringthedaywhenthesunishotandevaporation(andthereforedehydration)willoccurquickly.Theyopentheirstomataatnight,whentheairiscoolerandevaporationislessofaproblem.

Thesestomatatricksareprettyslick,butthere’sadownsidetothem.Thereducednumberofstomataandthedaytimeclosingsalsomeanthatasucculentleafcan’ttakeinasmuchcarbondioxideasanormalleafcan.Likecacti,succulentsneedtousethosealternativeformsofphotosynthesis:“C4”and“CAM.”Intheseformsofphotosynthesis,carbondioxideisbroughtinatnightandthecarbonsaresnippedoffandstoredintheformofanacid.(Youcouldthinkofitlikecanningfood,perhaps?)Thesucculentcellshavetobeveryefficientwiththeircarbonatomsbecausethereisalimitedsupplyofcarbondioxide.

The bumps are areoles.

This beautiful succulent is called aeonium.

This is a photo of a real stoma.

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Onelastsucculentsurvivaltrickworthmentioningishair.Someplantsgrowhairsontheirleavesorstemsinordertoprovidesomeextraprotectionfromthewindandsun.Thehairsactlikealayerofinsulation,slowingdowntherateofevaporation.Oncolddesertnights,dewcancondenseonthehairsandperhapsasmalltrickleofwaterwillreachtherootsbymorning. Areallythicklayerofhairsprobablyalsofunctionsasawaytodeterinsectsfrombitingintotheplant.Theinsectcan’tgetitsmouthpartscloseenoughtothestembecausethehairsgetintheway.Thisfeaturecanbeseenonplantsintemperate(notsohot)areasoftheworld,notjustinsuperdryclimates.Youmighthavesomeplantswithhairystemsandleavesgrowingrightnearyou.Sunflowers,forinstance,haveveryhairystems.Theplantcalled“Lamb’sEar”hasleavessofuzzytheyfeellikeanimalears,notplantleaves. Plant hairs are not made from the same stuff that animal hairs are.Animalhairismadeof“dead”proteinmolecules.Planthairsaremadeoflivingplantcells.Planthairsareproperlycalledtrichomes,andtheyareextensionsofepidermiscells.(Remembertheupperandlowerepidermiscellsfromtheleafcrosssection?)Thesespecializedepidermiscellscangrowtobeverylongandthin.Somehavespecializedcellsatthetipthatcansecretestrong-smellingsubstances.Thestrongsmellofmostherbs(suchasmint)comefromsmellyoilsproducedbyglandcellsonthetipsoftrichomes. Let’sturnnowtotheotherterribleoptionforplants:drowningin

water.Toomuchwaterwillkillmostplants,buttherearesomeplantsthatareadaptedforlivinginwaterallthetime.Whatadaptationswouldaplantneedtohaveinordertosurvivebeinginwaterallthetime?Wouldthestomatabeaproblem?Wouldwaterstillflowupthexylemtubes?Wouldtherootsneedtobeindirt?

Therearemanytypesofaquaticplantsandtheiradaptationsarejustwhattheyneedfortheirspecificenvironment.Someplantshavetheirrootssubmergedinwaterallthetimewhiletheirleavesstayoutofthewater.Otherplantshaverootsandstemsunderthewaterandleavesthatfloatonthesurface.Themostextremewaterplantslivecompletelysubmergedallthetime. Whatadaptationswouldaplantneedtohaveinordertobeabletolivesubmergedinwaterallthetime?Woulditneedstomataorcuticle?Whataboutroots?Woulditbeabletomakeflowers?

Seagrassesspendtheirentirelifeunderthewater.Theylookandactverymuchlikeregulargrass.Theyevenhavethosepeskyrhizomesthatletthemusevegetativereproductiontospreadveryquickly.Thisisannoyinginyourgardenwhenthegrassstartstakingoveryourstrawberrypatch,butalongseashoresthisabilitytospreadquicklyisaverygoodthing.Seagrassesareaveryimportantpartofshorelineecosystems.Seagrassesreproduceusingflowersandseeds,too.Thepolleniscarriedbywaterinstead of wind.

Seagrassleaveshaveneithercuticlenorstomata.It’spointlesstotrytokeepwaterinoroutwhenyouaresurrounded

byitallthetime!Thecellsintheleavesareokaywithbeingsaturatedwithwaterallthetimeandthecellshavemicro-adaptationsthatletthemtakecarbondioxiderightfromthewater.Likeallleaves,seagrassleavesneedsunlightforphotosynthesis.Thismeansthatseagrassescanonlygrowinrelativelyshallowwater.Ifthewaterbecomescloudybecauseofpollution,thedeeperseagrasseswillstarttodieout.Dyinggrassmightnotsoundlikeabigdeal,butseagrassesoccupyaveryimportantplaceinmanyaquaticecosystems.Seagrassbedsarefilledwithallkindsofanimallife.Ifthegrassesdisappear,sodotheanimals. Seagrasseshaveanotheradaptationthathelpsthemtosurviveinthewater.Theyhave

Some trichome cells are long and skinny. The round tips make smelly oils.

A manatee eating seagrass. (USGS photo)

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microscopicairsacsintheirleavesandstemsthatactlikelittlefloaties,keepingtheleavesuprightinthewater.(Ifyoutakeseagrassoutofthewater,itdroopsoveryourhandlikeawetnoodle.Theleavesdon’thavestiffcentralveinslikeregulargrassbladesdo.Seagrassesneedtobeabletobendandflexand“gowiththeflow”inthewater.Iftheirleaveswerestiff,they’dgettornapartbythemotionofthewater.)Thetinyairsacsintheleavesandstemsprovidejusttherightamountofbuoyancysothattheleavesstayuprightinthewater,reachingtowardthesunlight. Waterplantsaresurroundedbywater,sotranspirationisnotnecessary.Cellscangetwhatevertheyneedbyosmosis.(Remember,osmosisiswhenmoleculesgorightthroughthecell’smembrane.)Thecarbondioxide,water,andnutrientsareabundantallaroundthecells,soxylemtubesaren’treallynecessary.Inmostwaterplants,thevascularbundlesareverymuchreduced,andinsomecasestheyarealmostabsent.

Aslightlylessdrasticsituationiswhenaplantisonlypartlysubmergedinwater.Thebottomhalfoftheplantstaysinthewaterwhilethetoppartisallowedtotouchtheair.Agreatexampleofaplantadaptedtothissituationisthewaterlily.Let’stakeaclose-uplookatalilythatholdstheworldrecordforthelargestleafintheplantkingdom:theAmazonlily.

FoundintheAmazonRiverinSouthAmerica,thislilycangrowleavesthatareupto8feet(2.5meters)across.Thesegiantleavesarealmostperfectlyroundandlooklikefloatingplates.Theyarequitestableandcansupporttheweightofsmallbirdsandanimals.Theirstrengthisduetoanetworkofstrongveinsontheundersideoftheleaf.Theirabilitytofloatisduetosmallairpocketsinsidetheveins.Inadditiontobeingstrong,theseveinscanalsobedeadly—theyarecoveredinsharpspines.Fishlearnveryquicklythatnibblinglilyveinsisabadidea! Thebottomsidesofthelilyleaveshavetwootherfeaturesthatareworthmentioning.Likeseagrasses,theyhavenostomataandnocuticle.Unlikeseagrasses,theseundersideshavelotsofredpigmentinthem.Theredpigmentmoleculeshelptocatchwavelengthsoflightthataremissedbythegreenchlorophyllpigmentsontop. Thetopsideofalilyleafisnothinglikethebottomside.It’sgreen,iscoveredwithwaxycuticle,andcontainsstomata.Thetopsideisadaptedtolivinginair,thebottomsidetowater.

These three different types of seagrasses all have leaves that fl ex and bend with the water currents.

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ThelifecycleoftheAmazonwaterlilysoundslikesomethingfromafantasystory.Itsflowersbloomforonlytwodays.Thefirstnightitblooms,theflowerisfemale.It’swhiteandsmellslikefragrantperfume,anodorthatscarabbeetlesfindirresistible.Oncetheflowerhasattractedbeetles,itclosesup,trappingthebeetlesinside.Duringthenight,theflowerchangesitsgenderfromfemaletomale,anditscolorfromwhitetopink.Italsostopsmakingperfume.Whenthefloweropensupattheendofthesecondday,thebeetlesarefreedfromtheirfloweryprisonbutarecoveredwithpollengrains.Theflowernolongersmellsgood,sotheyflyofftofindanotherwhitelilyflower,carryingthepinkpollengrainswiththem. Oncefertilized,theflowerclosesandfallstothebottomoftheriverwhereitformsaseed.Theseeddoesnotbegintogrowuntilthenextyear.LilyseedsusuallygerminaterightastheAmazonRiverisreachingitsannualfloodstage,withthewaterrisingseveralinchesaday.Thenewlysproutedwaterlilystemmustgrowatanunbelievablyfastrateinordertokeepits“head”abovetherisingwater.Thestemiscapableofgrowingupto20feet(7meters)tallinjustafewweeks.Whenthewatersstoprising,thelilystartsgrowinggiantleaves(lilypads). It’sthenabattleoflilyversuslily,witheachplantattemptingtodominateitsarea.(Siblingrivalryhappensevenamongplants!)Onceagiantleafhasspreaditselfoutoverthewater,anyplantunderneathitwilldiefromlackofsunlight.Asidebenefitofthissituationisthatalgaeisalsopreventedfromgrowing.Thisiswhywaterlilies(usuallyvarietiesotherthanAmazon)areplantedinoutdoorwatergardens.Peoplewouldratherlookatlilyleavesthanalgae“scum.”

Oneofthesmallestaquaticplantsonearthiscalled“duckweed”or“waterlentils.”Duckweedlooksliketinygreendotsfloatingonthesurfaceofalakeorpond.Theyarebrightgreenandlookveryclean.Truetoitsname,

ducksloveduckweed.Otherwaterbirdseatittoo,aswellaspeopleinsomepartsoftheworld.It’sagreatsourceofprotein,evenbetterthansoybeans,anditproducesmorestarchperacrethancorn!It’spossiblethatduckweedcouldbeturnedintoethanolfuel,justlikecornis.Somedayourcarsmightrunonfuelmadefromduckweed! Aduckweedplantconsistsofjustatinyleaf,withnovisiblestemsorroots.(Insomespecies,theleaveshaveverysmallroothairsdanglingfromtheunderside.)Ifduckweeddoesn’thavestemsorrootscanitstillbeclassifiedasaplant?Wedecidedwaybackatthebeginningoflessononethatthereareonlytworequirementsforbeingaplant:1)youmustdophotosynthesis,and2)youmustbemadeofmorethanonecell.Duckweedqualifiesonbothcounts.Infact,it’sevenclassifiedasanangiospermsinceitoccasionallyproducesflowers—thetiniestflowersintheplantkingdom,nolargerthanthewidthofapieceofthread!

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ACTIVITY 1: SIT LIKE A LUMP ON YOUR CHAIR OR COUCH AND WATCH VIDEOS

Thisactivityshouldnotbetoodifficult.Logontowww.YouTube.com/TheBasementWorkshopandenjoythevideosaboutdesertplantsandwaterlilies.

ACTIVITY 2: PLANT PUZZLE

Fillinthemissingwordsintheclues,thentransfertheletterstothenumberedslotsunderneaththepictures.Assumingyou’vefilledinthecluescorrectly,you’llfindoutthenamesofthesucculentplantsinthepictures.(We’recountingcactiassucculents.Sometimesthewordsucculentisusedasamoregeneralterm,withcactibeingasubcategory.)

1)Succulentshavefewer_____________________andmore_____________________.6818941311122654536Theyalsohavegooeystuffcalled________________________intheirstemsandleaves.52549328422)Cactihavebumpscalled_____________________ontheir_______________.5938749553)Desertplantsmustusetwootherformsofphotosynthesis:“___4”and“_________.”9053394)Thewaterplantcalled________________________looksliketinygreendots.Eventhough7128664857itdoesnothavestemsorroots,itisstilla_______________becauseitdoesphotosynthesisandismadeofmorethanonecell.86310

5)Duckweedisverynutritious.Likesoy,itisagoodsourceof_____________________andlikecorn,itisagoodsourceof__________________.47719962067494162566)Likeallplants,whenaduckweedflowerispollinated,a__________________isformed.354670247)Thistypeofanimallovestoeatseagrass:_____________________.7216558)Planthairsarecalled___________________________andoriginatefromthe5087136333___________________________layer.21933478429)The__________________sideofanAmazonlily_________isthecolor_________and371597812587961hassharp__________________ontheveins.88602610)Whenwaterevaporatesoutthroughtheleaves,causinganupwardflowofwaterfromtheroots,thisiscalled_______________________________________.73692740297776641411)Thealoeplantissometimesusedtotreatthistypeofinjury:____________6925812)___________________________plantshavevery_______________stems.Thislets9123438075304451themstorewatersotheycan_____________________indesertclimates.178248913)Thiswordrootmeans“naked”inGreek:_______________839812

Z

BS

S

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____________________cactus____________plant__________plant123456789101112131415161718192021

______plant____________cactus________plant__________plant222324252627282930313233343536373839

____________________________________404142434445465152535455565758596061____________________47484950626364656667

______________________________________________________686970717273747576777879808182838485909192939495969798 cactus________cactusplant 86 87 88 89

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LEVELTWO

Wenowturntothemacabre(darkandspooky)sideofplantadaptations—plantsthateatanimals,makepoisons,andparasitizeotherplants.We’llmeetseveralofthestrangestplantsonearth. Whatwouldcauseaplanttobecarnivorous?(“Carn”means“fleshormeat,”and“vor”means“eat.”)Plantsusephotosynthesistomakeallthefoodtheyneed.Theydon’tneedanoutsidesourceoffoodenergy.Whatelsedoesaplantneedbesidescarbondioxide,water,andsunlight?Thinkaboutachlorophyllmolecule.Wheredoesaplantgetthosenitrogenandmagnesiummolecules?Asmitosisoccursandplantsmakenewcells,theyhavetogettherawingredientsneededtomanufacturemorechlorophylls,plusmanyothertypesofmolecules.Someofthesemoleculescontainatomssuchassodium,phosphorus,potassiumandcalcium.Carbondioxideandwateronlyprovidecarbon,oxygenandhydrogenatoms. Undernormalconditions,planttakethesemineralsfromthesoil.Plantsdon’t“eat”dirt,buttheydotakemineralsoutofit.Ifthesoildoesn’tcontainenoughminerals,theplantswon’tbeabletogrowthereunlesstheyhavesomealternatemeansofgettingminerals.Onealternativeistogetthemineralsfromthebodiesofanimals(mainlyinsectsandspiders). ThemostfamousofthecarnivorousplantsistheVenus flytrap.It’snotuncommontofindtheseflytrapsforsaleingreenhousesinmanypartsoftheworld,butifyouwanttofinda“wild”flytrapgrowinginitsnaturalenvironment,youwillhavetogototheAmericanstateofNorthCarolinaandfindabogwithin60milesofthecityofWilmington.Bogsareplacesthatarewetandsoggyallthetime.Thebogswheretheflytrapsgrowhaveverylittlenitrogenandphosphorousinthesoil.Theflytrapsareoneofthefewplantsthatthriveinthesebogs.Theygetverylittlecompetitionfromotherplantsbecauseofthislackofmineralsinthesoil.Theflytrapsappreciatenothavinganyrivalsinthearea.Infact,Venusflytrapsappreciateanoccasionalwildfireonceinawhile,too,justasaback-uptoremoveotherplantsfromthearea! Theleafofaflytrapisthesnappytrapontheend.Thelongflatpartthatlookslikealeafisactuallythepetiole.Thepetiolesaretheprimarysiteofphotosynthesis.Aswementionedintheopeningparagraph,flytrapsdon’teatfliestogetenergy.Theyusephotosynthesisjustlikeallplantsdo.Theflytrapisafloweringplant,asyoucanseeinthepicture.It’sevenadicot.Soinsomeways,it’s a very normal plant.

Thehingedleafontheendhastwouniquefeaturesthatworktogethertocatchflies.Thefirstisasetofthreetrichomes(“hairs”)ontheinsideofeachlobe,whichfunctionasmotiondetectors.Thesetriggerswillcausethetraptoclosesuddenlyifoneofthehairsistouchedtwiceveryquickly,oriftwoseparatehairsaretouchedwithin20seconds.Thesecondfeatureistheabiltyofthetwolobestosnaptogetherinabout1/10ofasecond. Plantsdon’thavemuscles,sohowistheflytrapabletodothis?Scientistsarestillinvestigating,butitseemsthattheanswerinvolvesthesuddenflowofwaterintoandoutofcells.Protonsareakeytothisrapidmovementofwatermolecules.Asuddenincrease

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ordecreaseintheamountofwaterinacellchangesitsshape.Anoverallchangeinshapecanbeseeninaflytrapleafafteritcloses.Whiletheleafisopen,thelobescurveoutward;afterclosingtheyarebentinward. Oncethelobeshaveclosedandthepreyistrapped,digestiveglandsonthesurfaceofthelobesbegintomakedigestiveenzymes.Basically,theclosedleafbecomesastomach!Theleafstaystightlyshutforabouttendays.Duringthistimethebodyofthepreyisreducedtoapuddleofmolecules,withmaybesomebitsofoutershellleftover.Afterthetrapopens,therainwillwashawaytheremainsofthemeal.Ifthepreyistoosmallandmanagestoescape,thetrapwillre-openinabout12hours.

Almostaswell-knownastheflytrapsarethepitcher plants.Theirleavesareshapedinsuchawaythata“pitcher”isformed.Likewaterpitchers,theseplantpitcherscancollectandholdwater.Pitcherplantsattracttheirpreyusingcolors,odors,andnectars.Theunsuspectingbugscrawlalongtheslipperyedgeofthepitcherandinevitablyslipandfallintothewaterpitbelow.Iftheymanagetoswimovertotheedgeofthepitcherandtrytoclimbout,theyfindthewallsofthepitcherextremelyslipperyorcoveredwithdownward-pointinghairsthatpreventthemfromescaping.Thebugsdrowninthewaterandtheirbodieseventuallydissolvewithsomehelpfromdigestiveenzymessecretedbytheplantcells.

Thepitcherplantsshownintheillustrationabovearethekindyoufindgrowinginthewarm,humidpartsoftheAmericancontinents.AverydifferenttypeofpitcherplantgrowsinIndonesia,southChina,andnorthernAustralia.Thescientificname(thegenus)forthesepitchersisNepenthes.ThisnamecanbetracedbacktoabookwrittenbyCarlLinnaeusin1737.ItcomesfromGreekmythology(Homer’sOdyssey),inastorywhereanEgyptianqueengivesHelenamagicpotionthatcauseshertoforgetallhersorrows.(“Ne”means“not,”and“penthe”means“grief.”)CarlLinneausexplainshischoiceofthisnameforthisplant: If this is not Helen’s Nepenthes, it certainly will be for all botanists. What botanist would not be filled with admiration if, after a long journey, he should find this wonderful plant. In his astonishment past ills would be forgotten when beholding this admirable work of the Creator!

TheNepenthesdoesnothavetorelyonraintofillitstraps.Itproducesathickfluidthatmakesescapeimpossiblefortheunluckyvictimsthatfallintoit.EvensmalllizardsandmammalscandrowninNepenthespitchers.However,afewspecieshavemanagedtooutwittheNepenthesandareabletostealsomeofitsfood.Carpenterantsliketonestinsidethetendrilsfromwhichthepitchershang.Thetendrilsarehollowsothisdoesnotharmtheplant.Theantsabletoswiminthepitcherfluidandwillworktogetherforhourstopulldeadpreyoutofthetrap.(Yes,theantsarecarnivorous,too!)Theplantactuallybenefitsfromthislivingsituationbecausetheantscleanupafterthemselvesandleavetheedgesofthepitcherspotless.Pitchersinhabitedbyantssurvivelongerthanthosethatare not.

Insomepartsoftheworld,theNepenthesiscalledthe“monkeycup.”Monkeysandlargeapesareknowntodrinkfromthesecups.(Ants?Yum,yum!)

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Anotherlargefamilyofcarnivorousplantsisthesundews.Thesundewshavetrichomesontheirleavesthatproducedropletsofclearstickyliquid.Theylookabitlikewaterdroplets,asifdewdropletshadformedonthetipsofthetrichomes.Thedropletssparkleinthesun.(The“sun”partofthenamecouldalsocomefromthefactthatthesundewsaresaidtohaveflowersthatturntowardsthesun.) Thedropletsproducedbythesundew’strichomesarebothsweetandsticky.Insectsareluredinbythesweetnessandtrappedbythestickiness.Aftertheinsectisstuck,thetrichomesbegintocoilaroundit,trappingitevenfurther.The

motioncanoccurquickly,withthetrichomesreactinginamatterofseconds.Withinseveralminutes,thewholeleafcanbecompletelycurledup.Digestiveglandsontheleavesthenreleaseenzymesthatdissolvethebodiesoftheinsects,eventheirtoughoutershell. Otherthantheirabilitytotrapanddissolveinsects,thesundews(likeallcarnivorousplants)arenormalfloweringplants.Theydophotosynthesisandtranspiration,theymakeflowersthatgetpollinatedbyinsects(differentspeciesthantheonesthatgettrapped)andmakeseedsthatgrowintonewplants.

Thelastcarnivorousplantonourlististhebladderwort. Thisplanthasdoubleadaptations.Notonlyisitcarnivorous,itisalsoaquatic.Inmostbladderworts,theonlypartoftheplantthatsticksupabovethewateristhestemthathasflowersonit.Theflowersareshapedabitlikesnapdragonsandcomeinawidevarietyofbrightcolors.

Thebladdersaretinylittlesacsthatgrowamongtheunderwaterleaves.Howtiny?Onaverage,theyareonlyabout1/4inch(1/2cm)indiamenter.Thewordbladderisaverygeneraltermthatmeansawater-filledorair-filledbag.Thecorrectnameforthebladderinyourbodyistheurinarybladder.Thewordbladderitselfdoesn’thaveanyconnectiontourine.Inthebladderwort,thebladdersarepouchesthatactashigh-speedtraps.Theycatchaquaticanimalssmallenoughtofitinsidethetrap.Pondwaterisusuallyfilledwithsemi-microscopiccrustaceans(relatedtocrabs)andinsectlarvae.

Thebladdershaveadesignthatallowsthemtotemporarilyforcetheirshapetocurveinward,causingstructuraltensionthatisabitlikepullingbackaspring.(Remember,plantsdon’thavemsucles,sothismovementiscausedbywaterandmineralsflowinginandoutofcells.)Thetraphassometriggerhairsaroundtheopening.Whenasmallanimalbumpsintothetriggerhairs,theshapeofthetrapsuddenlypopsbacktoits

normalopenstate,causingwatertorushin.Theanimalissweptalongwiththemini-currentandissuckedintothetrap.Thetrapcansnapshutinonly1/10,000ofasecond! Asyoumightguess,therearedigestiveglandsinsidethetrapthatdissolvetheanimal’sbody.Whendigestionisfinished,thetrapcanejecttheremainsandresetitself,pullingitsshapeinwardagain.

The things that look like roots are actually leaves. Both leaves and bladders remain under the water all the time. Only the flower sticks up out of the water. The plant does not need roots because the leaves are surrounded by water.

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Somebotaniststhinkofaplant’sabilitytomaketoxins(poisons)asanadaptationbecauseithelpstheplantsurvive.Plantshaveveryfewwaystoprotectthemselvesfromgettingeaten.Remember,plants“want”tosurvive,too,justasmuchasanimalsdo.PlantDNAisengineeredtocausethemtotrytoreproduceasmuchaspossible,andtoadaptthebesttheycaninordertothriveintheirenvironment.(Infact,inapastchapter,weaccusedthemofbeingbentonworlddomination!)

Toxinsareaveryeffectivewayforaplanttomakeitselflesslikelytobeeaten.Aplant’sprimaryenemiesareinsects,sothetoxinsarereallytargetedatthem,notatanimalsorhumans.Since

insectsareverysmall,ittakesonlyasmalldoseofthetoxintokillthem.Thedosethatkillsabugwon’tdomuchdamageatalltoalargeanimaloraperson.However,therearesomeplantsthatproducetoxinsstrongenoughtodamageevenalargemammal. Itwouldbeveryboring(orperhapsalittlescary)foryoutoreadalistoftoxicplants,sowe’lljustlookattwoplantsthatplayedapartinGreekandRomanhistory.

Perhapsthemostfamouspoisonousplantinhistoryisthehemlock.TheGreekphilosopherSocrateswasforcedtodrinkacupofpoisonhemlockaspunishmentforhis“impiety”(meaninghewasteachingyoungpeopletothinkforthemselvesinsteadofjustacceptingwhateverthemembersoftherulingclasstoldthem).Thishemlockplantisnotrelatedtothetreecalledthehemlock.Theyareentirelydifferent.Thescientificname(genus)forSocrates’hemlockis Conium.ThiswordcomesfromtheGreekword“konas,”meaning“towhirl.”Apparently,beingdizzy(feelinglikeyouarewhirling)isoneofthesymptomsofamildcaseofhemlockpoisoning.

Thescientificnameofthisplant,Atropa belladonna,soundsbeautiful,butit’scommonnamestellyouallyouneedtoknowaboutit:“devil’sberries,”or“devil’sherb.”Morerecently,ithasbeencalled“deadlynightshade.”Itbelongstothesamefamilyofplantsasthetomatoandthepotato(solanaceae,the“nightshades”).Thename“belladonna”comesfromItalianandmeans“beautifulwoman.”Whenthejuicesofthisplantareusedaseyedrops,theycausethepupilstodilate.AncientItalianwomenlikedtohavetheirpupilsdilatedwhentheymetanattractiveyoungman.Theythoughtthismadethemlookmorebeautiful.

Whengroundupandmixedintoapotion,thisplantdoesmorethandilateyourpupils—itkillsyou.ThewivesoftheRomanemperorsAugustusandClaudiusareknowntohaveusedthisplanttopoisontheirenemies.Beforetheydied,the

victimswouldhaveexperiencednotonlydilatedpupilsbutalsomentalconfusion,rashes,headache,lossofbalance,blurredvision,racingheart,sweating,hallucinationsandconvulsions.Notfun. Interestinglyenough,cowsandrabbitscaneatthisplantandhavenoilleffects.Fortherestofus,ahandfuloftheseberriescankillus.Sincetheberrieslookprettyandtastesweet,thisisadangerforsmallchildren.Fortunately,treatmentisavailableifyougettoamedicalfacilityquickly.AchemicalproducedbytheAfricancalabarbeanplantcanreversetheeffectsofthebelladonnatoxin.Butdon’ttaketoomuchofthisbeanchemical,becauseinhighdosesthiscurecanbetoxic,too.Thecalabarbean’stoxinisconsideredtobeoneofthemostpotentintheplantkingdom.

A GENERAL GUIDELINE FOR AVOIDING POISONOUS BERRIES: Don’teatanyberriesyoufindgrowinginthewildiftheyhaveasimple,roundshape.Berriesthatarelumpy,likeraspberries,areneverpoisonous.Somesmoothberriesareokay,butlotsofthemaretoxic.Don’ttakechances—juststayawayfromsmoothberries!

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Ourtourofthecreepysideofbotanyendswithalookatplantsthathavebecomeparasites. Aparasiteisanyorganismthatmustliveinoronanotherorganism.Manyparasitesendupharmingtheirhosttosomedegree,butnotsomuchthattheykilltheirhost—oratleastnotuntiltheparasitehashadachancetoreproduce.Wetendtohaveverynegativefeelingsaboutparasites,butaswewillsee,someparasiticplantscanbebeneficialtotheecosystemtheylivein.

Themostwell-knownparasiticplantisthemistletoe,theplantthathasbeenpartofChristmascelebrationsinwesternculturesforhundredsofyears.Abranchofmistletoeishungatthetopofadoorwayorsuspendedfromtheceiling.Coupleswho“happen”tocrosseachother’spathsunderthemistletoearepermittedakiss.Foreachkiss,aberryispluckedoffthebranch.Whentheberriesrunout,sodothekisses.

Youdidn’tknowmistletoewasaparasite?Mostpeopledon’t.Thename“mistletoe”(originally“mistiltan”)mostlikelycomesfromtheAnglo-Saxonwords“mistel”meaning“dung,”and“tan”meaning“twig.”Sothatmakestherealnameforthisplant“dung-on-a-twig.”Thedunginquestioncomesfrombirds.Birdseattheberries,andsomeoftheirdroppingfallontreebranches.Mistletoeseedshappentobeverysticky,sotheyquicklyadheretothebranch.Whentheseedsgerminate,theycangrowforawhileinthebirddropping,asifitwasdirt.Asquicklyastheycan,though,thebabymistletoeplantsstartputtingoutspecial“roots”calledhaustoria (hoe-STORE-ee-ah).Thehaustoriasomehowgrowtheirwaythroughthetree’sbarkandgetintothesapwoodwherethelivingxylemandphloemtubesare.Theyputtheirthinroot-liketubesintothetree’sxylemandphloem,asifputtingadrinkingstrawintosomeoneelse’sglass.Themistletoeslurpsaway,suckingwater,mineralsandsugarsfromthetree’svascularsystem.Thus,themistletoeispermanentlyattachedtoatree,insteadofgrowingintheground. Themistletoeiswhatbotanistscalledahemiparasite(“hemi”

meaning“halfway”).Theleavescanstilldophotosynthesis,soitisnotcompletelyreliantonthehosttree.Atfirst,thetreehardlynoticesthemistletoeandisn’tespeciallybotheredbyit.Ifrainfallisadequate,thereisenoughwaterforbothplants.However,asthemistletoegrowslargerandlarger,thereisagreaterpossibilitythatthetreewon’tbeabletokeepupwiththeincreasingdemandsthemistletoeplacesonit.Sometreesdoeventuallydiefrommistletoeinvasion,and,ingeneral,gardenersseemistletoeasathreat.Theyusuallypruneoffanytreebranchesthatshowmistletoe infestation.

Onlyrecentlyhaveresearchersdiscoveredthatinsomeplaces(Australiabeinganotableexample)somespeciesofmistletoearequiteabenefitto

thenaturalenvironment.Thoughmistletoeberriesaremildlypoisonoustohumans,birdslovethem.Areaswithalotofmistletoewillhaveadensepopulationofnestingbirds.Also,theleavesandyoungshootsofmistletoeareafavoritesnackforcertaintypesofanimals.Thus,areaswithmistletoetendto have more wildlife than areas without mistletoe. Biodiversity(thepresenceofmanydifferentformsoflifeinsteadofjustafew)isconsideredtobeagoodthing.Ecologistsallovertheworldareinagreementthatit’shealthyforanecosystemtohavelotsofdifferentspecieslivingtogether.

Otherparasiticplantsarewhatscientistscallobligate parasites.Theword“obligate”isrelatedtothewords“obliged”and“obligated.”Theseparaitesarecompletelydependentupontheirhostplant.Infact,theseplantshavelosttheabilitytodophotosynthesis.

A mistletoe starting to grow on a tree branch.

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]

Umm...well,howelsecanweclassifythem?They’renotfungi,bacteria,animalsorsingle-celledorganisms.Theymakeflowerswithpistilsandstamens—that’splant-like.Botanistsguessthatonceuponatimetheseplantsdiddophotosynthesis.Oncetheystartedfeedingonotherplants,theirneedforphotosynthesisdisappeared.Thecellssomehowsensedthisandstoppedmakingchlorophyll.Thisisjustaguess,ofcourse,asnoonewastheretowitnessthiswhenithappened.It’sjustatheory.However,thepossibilitythatthiscouldhavehappenedgivesuslicensetogoaheadandclassifyobligateparasiticplantsasplants.

ThemostfamousobligateparasitegrowsontheislandsofBorneoandSumatra.ItsscientificnameisRafflesia, (andmanypeopleusethisname),butitisalsocommonlycalledthe“carrionflower.”“Carrion”isapolitenamefordeadanimals.Yes,thisflowerstinkslikerottinganimalcarcasses.Why?Becauseanyinsectcanpollinateaflower.Itdoesn’thavetobecutelittlebutterfliesandbumblebees.Inthiscase,thestinkingflowerdrawsflies.Thefliesarefooledintothinkingthatthereisrottingmeatinsidetheflower,andpollinationisaccomplished.

TheRafflesiaholdstheworldrecordforbeingthelargestflowerintheworld—whichiskindoffunnywhenyoulearnthatthefloweristheonlypartthisplantreallyhas.Ithasnoleaves,nostemsandnoroots!(Atleastyouknewthatthosepartsaren’tincludedinthedefinitionofwhatmakesaplantaplant.)TheonlyotherparttheRafflesiahasisanetworkofhaustoria.Thehaustoriaareembeddedintotheveinsofavineplant,and

areinvisiblefromtheoutside.TheonlytimeyoucanbesuretheRafflesiaplantisthereiswhenitputsoutaflowerbud.Otherwise,youneverseethisplant!

Oursecondandlastobligateparasiteisthe“snowflower.”(Thebudsoftenpopupearlyintheyear,pokingupthroughthesnow.)LikeRafflesia,thistypeofplanthasnoleaves,nostemsandnoroots.Itconsistsofnothingbuthaustoriathreadslivinginsideafungusthatlivesonotherplants.Sincetheseplantsliveonafungus,somepeopleliketocallthem“fungusflowers.”Thesnowflowertakesitsnourishmentfromafungusthatistakingitsnourishmentfromaplant.Soindirectly,thesnowflowersarefeedingonaplant,butthroughthefungus.Verystrange,indeed. These snow flower buds were found in Yosemite

National Park in California.

Picture credits: Rafflesia by ma_suka on Wikimedia Commons, snow flower by Walter Seigmund, posted on Wikipedia article: Sarcodes.

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ACTIVITY 1: “O” THAT RAGWORT IS A PROBLEM!

Ragwortisawildflowerintheasterfamily(samefamilyasdaisies).Ithasprettyyellowflowersandlooksnicegrowingbytheroadside.ItisnativetoNorthernEurope,butcannowbefoundinplacesallovertheworld,includingAustralia,NewZealand,Argentina,India,northernAfricaandsomestatesinAmerica.Therearecertainmothsandfliesthatlovetofeastontheleavesandnectar.Infact,theywon’teatanythingelse.Theseinsectsdon’treflecttheopinionsoftheanimalkingdomingeneral,however.Ragwortisverybitterandmostanimalswon’twillinglyeatit.

Farmersallovertheworldareonamissiontotrytomakethisplantextinct(muchtothedismayofinsectenthusiasts).Thebittertasteofragwortisduetotoxins(poisonouschemicals)itproduces.Thesetoxinshelptheplantbykeepingitsafefromhungryanimals.However,astheplantdriesout,thetoxicchemicaltastelessbitter.Ifdriedragwortgetsmixedinwithhorseorcow’shaysupply,theanimalwon’tbeabletodetecttheragwortinitsfood.Theywillaccidentallyeattheragwortandthetoxinswillgetintotheirbloodstreamandpoisontheirlivers,makingthemverysick.Insomeplaces(suchastheUKandsomeUSstates)ifyoufindragwortgrowingonyourpropertyyouarerequiredbylawtodestroyit. Onewayyoucanidentifyragwortisbycountingthepetalsofitsflowers.Ragwortflowershave13petals.Therearen’ttoomanythingsinthenaturalworldthatcomein13’s.Oneofthefewplaceswherethenumber13showsupinflowerpetals.Othercommonpetalnumbersare4,5,8,10,and21.Mathematiciansthinkitisinterestingthatpetalnumbersroughlycorrespondto“Fibonacci”numbers:1,2,3,5,8,13,21,34...(addthetwopreviousnumberstogetthenextone).

Thisragwort’s13petalscorrespondto13botanical“rootwords”fromLatinorGreek.Theeasypartisthatalloftheserootwordsendintheletter“O”whichalreadyappearsinthecenteroftheflower.Fillintherestofthelettersstartingattheoutsideofthepetalandgoingtowardsthe“O.”Youmayhavetoturnyourpapersidewaysandupsidedown!(Ifyouneedahint,apagenumberisgivenwhereyoucanfindtheanswer.)

1)light(pg 1) 2)verysmall(think of a scientific instrument that lets you see very small things)3)green (pg 8)4)middle(pg 38)5)one(pg 31)6)turn(pg 36)7)tree(pg 40)8)life(think of the branch of science that studies life)9)flower(pg 44)10)naked(pg 50)11)vesselorcontainer (pg 52)12)yellow(pg 39)13)airorbreath(pg 8)

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ACTIVITY 2: MORE VIDEOS! (unless you watched them already)

Getcomfy,gotowww.YouTube.com/TheBasementWorkshop,andwatchsomefascinatingvideosoncarnivorousplants.

ACTIVITY 3: TRUE OR FALSE?

Canwetrickyou?Seeifyoucandeterminewhethereachstatementistrueorfalse.

1)___Flytrapscansurvivewildfires.

2)___Bogshavemineral-richsoil.

3)___Variousspeciesofflytrapsliveallovertheworld.

4)___Flytrapleaveshavenopetioles.

5)___Flytrapshavemusclecells.

6)___Nepentheshaveparasiticantsthatdestroytheirpitchers.

7)___Nepentheswerenotdiscovereduntilthe20thcentury.

8)___Allcarnivorousplantshavedigestiveglands.

9)___Pitcherplantscanbefoundgrowingonseveralcontinents.

10)___Nepenthesplantshaveasymbioticrelationshipwithaparticularspeciesoftropicalspider.

11)___Sundewtrichomescanmove.

12)___Carnivorousplantsproducepoisonouschemicalstoparalyzetheirprey.

13)___Thebladderwort’strapisprobablythefastest-actingmechanisminnature.

14)___Bladderwortshavenoroots.

15)___Bladderworttrapscanbeusedonlyonce.

16)___Socratesdiedbydrinkingapotionmadefromthehemlocktree.

17)___AConiumplantmakescones.

18)___Someanimalscaneatdeadlynightshadeandsurvive.

19)___Sometimesanimalsarenotbotheredbyplanttoxinsthatarefataltohumans.

20)___Nevereatwildraspberries.

21)___Themistletoeplantdoesnothaveroots.

22)___Ahemi-parasiticplantcanstilldophotosynthesis.

23)___Mistletoeplantsruinwildhabitats.

24)___TheRafflesiahasonlytwoparts:haustoriaandflowers.

25)___“Snowplants”arereallyatypeoffungi.

This is a species of pitcher plant called the cobra lily.

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LESSON 7Level1Activity1:1)stomata,cuticle2)areoles3)C4,CAM4)duckweed,plant5)protein,starch6)zygote7)manatee8)trichomes,epidermis9)bottom,pad,red,spines10)transpiration11)burn12)succulent,bulky,survive13)gymno PLANTSfromlefttoright,toptobottom:Firstrow:agave,brain,cocoon,stoneSecondrow:ice,pencil,aleo,zebraThirdrow:pricklypear,yucca,henandchicksFourthrow:saguaro,barrel,organpipe,curiosityLevel 2Activity1:1)photo2)micro3)chloro4)meso5)mono6)tropo7)dendro8)bio9)antho10)gymno11)angio12)xantho13)spiroActivity2:1)T2)F3)F4)F5)F6)F(pitcherisnotdestroyed7)F8)T9)T10)F11)T12)F13)T14)T15)F16)F(notthehemlocktree,butrathertheconiumhemlock)17)F18)T19)F20)F21)T(haustoriainsteadofroots)22)T23)F24)T25)F

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LESSON 7

1) FUN GAME: “Don’t Sink the Lily Pad!”

You will need: •Aluminumfoil •Apanorlargebowlofwater(severalinchesdeepisbest) •Scissors •Alargebowlofpennies(acoupleofdozenforasmallpad,severalhundredforapadthatisthesizeofadinnerplate)Youcouldalsouseddriedlimabeansorothersmallobjects.

How to prepare: Cutthreefoilcircles:asmallone(justafewinchesacross),amedium-sizedone(morelike4or5inchesacross)andalargeone(7to10inchesacross).FolduptheedgestomakeitlooklikearealAmazonlilypad.Refertothepictureinthechaptertoseethatthesepadshaveaverysteep“lip”allaroundtheedge.(Tip:Thehigherthelip,themorepenniesyouwillbeabletoplaceonthepadbeforeitsinks.)

How to play: Placethesmallestpadinthepanofwater.Itshouldfloatverywell.Lettheplayerstaketurnsplacingpenniesonthepad.Theideaistobeabletoplaceapennywithoutsinkingthepad.(Youcouldpretendthatthepenniesarefrogsorbirdsthatmightbefoundsittingonalilypad.)Thepersonwhosepennysinksthepadistheloser.(Youcanavoidhavingaloserbyjustmakingitfuntoseehowmanypennieseachlilypadwillhold.)Asthegameprogress,theplayerswillstartseeingstrategy—howtoaddpennieswithoutupsettingthebalanceofthepad.Playerswholikephysicalsciencewilllikethisgame. Aftertryingthesmallpad,moveuptothemediumpad,thenthelargepad. Duringthegame,asktheplayerswhattheynoticeabouthowthepadholdsweight.Whathappenswhenthepadfinallygivesway?Whereistheweakestpointonthepad?(Usuallythelowestpointonthelip.) Asanadditionalinvestigation,punctureasmallholeinoneofthepadsandtryitagain.Howmuchdifferencedoesasmallholemake?Punctureafewmoretinyholes.Anydifference?Whataboutalargehole?

2) MAKE A PAPER MODEL THAT SHOWS HOW A CACTUS STEM EXPANDS

You will need: •Paper •Scissors •Tape

Cuttwolongstripsofpaper(fromthelongsideofapieceofpaper).Foldthembackandforth(“accordion”style).Tapetheendstogetherandadjusttheshapesoitlookslikeoneinthepicture. Experimentwiththemodel.Demonstratehowacactusisabletoexpandsuddenly.

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3) PLAY A GAME ABOUT POISONOUS PLANTS: “Where Sheep May Safely Graze”

ThenameofthisgamecomesfromapieceofmusicwrittenbyJ.S.Bach(CanonNo.208).Heprobablywasn’tthinkingaboutpoisonousplantswhenhewroteit,butthetitlewasjusttootemptingtoresist. Theboardisdesignedfor1-4players,soifyouwillhavemorethan4players,maketwocopiesofthegameboard. Allplayerscanstillplayasagroup,butonseparateboards.

You will need: •Copiesofthegameboardpiecesandcopiesofthesheeptokens(onesheepperplayer) •Tape(agluestickmightalsobehelpfulforassemblingthesheeptokens) •Scissors •Optional:coloredpencilsormarkerssoplayerscancolortheirsheepinordertoidentifyit

How to set up the game: Tapetogetherthetwogameboardpages.Cutout,foldandassemblethesheeptokens.Eachplayershouldeitherwritehisnameonthesheep,orcolorthefleecesothathewillbeabletokeeptrackofhissheep.

How to play the game: Theobjectofthegameistogetyoursheepacrossthelongmeadowwithouteatinganypoisonousplants.Thiswillbedifficultbecausethreeoutoffourplantsineachrowaretoxictosomedegree.Onlyoneisconsideredbybotaniststobeedible.Notallthetoxicplantsareequallytoxic.Somewilljustcausestomachupsetorheadaches,otherswillkillyou.Aswithallthings,“Thedosemakesthepoison,”asParacelsusstatedbackinRenaissancetimes.Inmostcases,theamountyoueathasalottodowiththeoutcome.Eachplanthasbeengivenanumericalestimateofhowtoxicitis,usingascaleof1to3.(Thisisnotanofficialnumberyou’llfindanywhere.Thesenumberswerecreatedforthisgameandshouldnotbeconstruedasscientificallyvalidtoxicityestimates.)Edibleplantshaveatoxicityscoreof0,sothegoalistoendupwithascoreascloseto0aspossible.

Disclaimeratthispoint:Eventhoughthetokenisasheep,we’veerredonthesideofchoosingtodefineedibilitybyhumanstandards,notgrazinganimalstandards.Inmostcases,humansandanimalswillreactinasimilarmanner,butiftherewasanydiscrepancy,thehumanfactorwasgivenmoreconsiderationsincetheplayersarehumanswhomightfindthisinformationhelpfulatsomepointinthefuture.

Thisgamerequiresaleader(mostlikelytheteacher/adultincharge,butitcouldbeastudent,especiallyifyouhaveanolderstudentandsomeyoungerones).Theleaderwillgivethecorrectanswersaftereachmoveandwillalsobeabletoaddsomeextrainformationathis/herdiscretionfromtheextrainfosheet.

Allplayersmoveatthesametime.Theleadercallsoutthenumberoftherowthesheepwillbegrazing,movingfrom1to12.Theplayersthenplacetheirsheepontheplantinthatrowthattheyhopeisedible.Afterallsheephavebeenplaced,theleaderreadstheanswersandgivesthetoxicityratingforeachplant.Theplayerswritedowntheirscoreforthatrow.Astheyprogressuptherows,theykeepaddinguptheirpointssothatafterrow12theywillhaveafinalscore.Thelowestscorewins.

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azalea hibiscus rhododendron hydrangea

gooseberries asparagusberries pokeweedberries yewberries

tulipbulbs orchidbulbs daffodilbulbs hyacinthbulbs

maple tree leaves

dogwoodtree leaves

cherrytree leaves

oaktree leaves

rawkidneybeans rawlimabeans rawgreenbeans rawMungbeans

cherrypits grapeseeds apple seeds pear seeds

Where Sheep May Safely Graze

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8

9

10

11

12

azalea hibiscus rhododendron hydrangea

gooseberries asparagusberries pokeweedberries yewberries

tulipbulbs orchidbulbs daffodilbulbs hyacinthbulbs

maple tree leaves

dogwoodtree leaves

cherrytree leaves

oaktree leaves

rawkidneybeans rawlimabeans rawgreenbeans rawMungbeans

cherrypits grapeseeds apple seeds pear seeds

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potato leaves

tiger lily

violets

ferns

whitesnakeroot

wildcarrots

Threeoftheplants(orplantparts)ineachrowaretoxic.Oneisedible.

Goodluck,sheep!

1

2

3

4

5

6

Trimoffthetopofthispagethentapeorgluethispagetothebottomofpreviouspage.

potato leaves

potato stems

greenpotatoes red potatoes

tiger lily

lily of the valley Jack-in-the-pulpit callalily

violets buttercups foxglove larkspur

ferns ivy holly cattails

whitesnakeroot jimsonweed ragwort nettles

wildcarrots

dandelion leaves

rhubarb leaves

tomato leaves

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Where Sheep May Safely Graze

Thispageisanextraincaseyouwanttomakeyourowngame,oraddadditionalrowstotheotherpages.

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potatoleaves(1)PotatoesbelongtotheSolana-ceaefamily,thenightshades.Allnightshadesproduce

solaninechemicals,atleasttosomedegree.Thischemicalismostabundantinthegreen

parts of the plant.

potatostems(1)

Sincepotatostemsaregreen,theycontainsomesolanine,achemicalthatcanaffectboththedigestivesystemandthe

nervoussystem.Cookingdoesnotdestroythischemical.

greenpotatoes(1)

Eatingafewbitesofgreenpotatowon’tmakeyouterriblysick,buteatingalotofthemisn’tgoodforyou.Thegreencolorindicatesthepresenceofsolanine,atoxicchemical.

redpotatoes(0)

Thetubersofpotatoplantsdonotcontainmuchsolanineaslongastheyarewhiteorredin

color.

tigerlily(0)

Tigerliliesareedibleandaresometimesusedtogarnishsal-adsanddesserts.Theybelongtothefamilyofdaylilies,whicharechemicallydifferentfromotherplantswecalllilies.

lilyofthevalley(2)

Thoughitlooksgreatinyourflowergarden,allpartsofthisplantcancauseabdominalpain,vomiting,andreducedheartrate.Eatingalargeamountcanbedeadly.

Jack-in-the-pulpit(1.5)Thisplantcontainssaponins,whichcausesevereirritationtothemouth,throatandstom-ach.Inseverecases,swellingcausesproblemswithbreath-ing.Whencookedproperly,the

rootcanbeedible.

callalily(3)Thistypeoflilycontainsoxalicacid(alsofoundinrhubarbleaves)andcausesdigestivedistress.Theacidcanaffectotherorgans,also,andadoseofaslittleas5gramscanbe

fataltosmallchildren.

violets(0)

Violets are often used to add colortoagreensalad.They

arehighinvitaminC.

buttercups(1)

Theselovelyflowerscanbeadangertograzinganimals.Theycancausecholicin

hoofedanimalsanddigestivedistressinallanimals.Theycanalsoirritatetheskin.

foxglove(2)

Thisplantcontainsdigitoxin,achemicalthatwillmakeyounauseated,thencauseseriousheartproblems.However,insmalldosesthischemicalisusedasaheartmedication.

larkspur(2)

Thetoxinsinthisplantcauseproblemstomusclesand

nerves,andcanbefatal.Thisplantcausesproblemsingraz-inganimals.Inlatesummer,theplantbecomeslesstoxic.

ferns(.5)

PeopleinAsiaeatfernfiddle-heads with no apparent ill ef-fects.However,allfernshavebeenshowntobecarcinogenicandtheyareprobablycontrib-utingtoJapan’shighratesof

digestivecancers.

ivy(1)

Ivyleavesandberriesaremild-lypoisonous,causingdigestivediscomfortandlaboredbreath-ing.Theirbittertastehelpstokeephumansfromeatingthem.

holly(1)

Hollylooksniceasaholidaydecoration,butdon’teatit.Itwillgiveyounausea,vomiting

and diarrhea.

cattails(0)

Allpartsofthecattailareed-ible.Somepeoplegrindtherootsintoaflour.Thestemsaretenderandtastelikecu-

cumber.Thebrownspikescanbeeatenlikecornonthecob.

whitesnakeroot(2)Allpartsofthisplantare

toxicduetoachemicalcalledtremetol,whichcausesseveretremblingandvomitingandcanbefatal.Thetoxincanpass

throughacow’sudderandintoitsmilkcausing“milksickness.”

jimsonweed(3)Likedeadlynightshade,jimsonweedcontainsachemical

calledatropine,whichinterfereswiththenormalfunctioningofthenervoussystem.Inverysmallamounts,thischemicalcanbeusedasamedicine.

ragwort(2)

Thisplantismostdangeroustograzinganimals.Itisbitterandthereforeunlikelytobecon-sumedbyhumans.Itcausesliverdamagebecauseofitsmanyalkaloidchemicals.

nettles(0)

Thoughtheyhaveareputa-tionforbeingnastystingers(becauseofthehairsontheirstems),cookingthemremovesthestingandmakesthemcom-

pletelyedible.

wildcarrots(1)Thecarrotswegrowinourgar-dens are far removed from their wildcousins.Itisadvisablenottoeatthingsyoufindinthewildthatlooklikecarrots.Theycan

bepoisonous.

dandelionleaves(0)Dandelionleavesareagreatsourceofvitamins,minerals,andfiber.Allpartsoftheplantareedible,eithercookedorraw.Manypeopleusetheleavesassaladgreens.

rhubarbleaves(1)Rhubarbleavescontainoxalicacid,whichcancausekidneydamage,convulsionsand

coma.However,you’dhavetoeatquiteafewofthemto

achievetheseextremeeffects.

tomatoleaves(1)Thesecontainsolanin,whichcancausestomachupset

and nervous system distress. Tomatoesareinthenightshadefamilyofplants,Solanaceae,alongwithAtropabelladonna,jimsonweed,andpotatoes.

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azalea(2)

Theazaleaisasmallrhododen-dron.Thenectaroftheazaleaflowersisalsotoxic,soifbeesmakehoneyfromazaleas,the

honeywillbetoxic.

hibiscus(0)

Hibiscusplantsarefamousfortheirhugeflowers.Sincetheflowersareedible,theycanbeusedasdisposableplates!

rhododendron(2)Rhododendronsarethelargergroupofplantstowhichazaleasbelong.Rhododendronsarelargebusheswithhugeball-

shapedflowers.Aslongasyoulookanddon’ttaste,you’reOK!

hydrangea(1.5)Hydrangeaaredistantlyrelatedtorhododendrons,butcontainthesametoxicchemicalsfoundin the Prunusfamily(fruitswithpits).Thesechemicalsmainlyaffectthedigestivesystem.

gooseberries(0)

Gooseberriesareoneofthefewsimple,roundberriesthatareedible.Theyarerelatedtocur-rants and are native to Europe andAfrica.Theyareusedinsalads,dessertsandjams.

asparagusberries(.5)

Asparagusberriesaresome-whatcontroversial,butthegen-eralconsensusistorefrainfromeatingthem,astheyhavebeenreportedtocausetoxiceffects.

pokeweedberries(1.5)

Thepokeweedplantisacom-monweed.Theripeberriesaredarkpurpleandcanbeusedasanaturaldye.Eatingmorethanafewberriescancausenausea

andheadache.

yewberries(2)Thesebrightredberriesare

foundonbushesthathavesoft,flatneedles,likeanevergreen.Eatingmorethanafewberriescancausevomiting,diarrheaanddizziness.Eatingalotof

themcanbefatal.

tulipbulbs(1)Mostofthetulipbulbismod-eratelytoxic.DuringWWII

peopleinHollandatetheouterpartsoftulipbulbswhenfacedwithstarvation.Theknewthecentralpartofthebulbwastoxic

and did not eat it.

orchidbulbs(0)

Orchidsarenotcloselyrelatedtotheseotherbulbs,sotheir

chemistryisdifferent.Allpartsoftheorchidplantareedibleandtheflowersareoftenusedin

salads and desserts.

daffodilbulbs(2)

Daffodilsarerelatedtotulipsbuttheirbulbsseemtobemoretoxicthantulipbulbs.Eatingdaffodilbulbscausesintense

vomitinganddiarrhea.

hyacinthbulbs(2)

Related to tulips and daffo-dils,hyacinthsarealsotobeavoided.Thealkaloidchemi-calscauseintensedigestive

misery,andcanalsoaffectothersystemsofthebody.

mapleleaves(2)Thesearemoreofadangertograzinganimalsthanpeople,ashorsesfindthemtastyandpeopledonot.Theleavesgetmoretoxicastheywiltandturncolors.Onlyafewpoundsof

them will poison a horse.

dogwoodleaves(0)

Theleavesandberriesofthedogwoodtreearenon-toxic.

cherryleaves(2)

Theleavesofthecherrytreecontainthesametoxicchemi-calsfoundintheseeds.Horseownersareverycarefultokeepcherrytreeleavesoutoftheir

animals’ pastures.

oakleaves(1)

Oakleavescontainhighlevelsoftannicacid,whichcausesdigestiveupsetandpossiblyothersymptomsathighdoses.Itcancausegrazinganimalstocholic.Pigsarenotaffected.

rawkidneybeans(2)Rawkidneybeanscontainasubstancecalledlectin,whichisbeneficialtotheplant,butnottoyou.Even4-6rawbeanscancausegreatdistresstoyour

digestivesystem.Boilingbeansfor10min.destroysthelectins.

rawlimabeans(1)

Rawlimabeanscontainasub-stancecalledlinamarin,whichisfairlytoxic.Whenboiledforjust10minutes,thischemicalisbrokendownandbecomes

harmless.

rawgreenbeans(.5)We’vealleatenafewrawgreenbeansonceinawhile.Don’tpanic!Afewwon’tharmyou.Justdon’teatabushelofrawbeansoryou’llgetsomedis-

tressingdigestivedisturbances.

rawMungbeans(0)Mungbeansbelongtothege-

nus VignaandcomefromIndia.TheotherbeansinthisrowaregenusPhaseolus and are native totheAmericas.Mungbeanscanbeeatenraworcooked.

cherrypits(1)AllmembersofthePrunus fam-ilyhavecyanogenicglycosidechemicalsthatattackthecellsinyourdigestivesystem.Alargedoesofthesechemicalscanaffectotherorgans,aswell.

grapeseeds(0)Grapeseedsarenotonlynon-toxicbuttheyarebeneficial.

Grapeseedextractisapowerfulanti-oxidant,protectingyour

cellsfromdangerousmoleculescalled“freeradicals.”

appleseeds(.5)

Appleseedscontainsmallamountsofatoxiccyanide

chemical,butyou’dhavetoeathundredsofseedstoproduceanynoticeablesymptoms.

pearseeds(.5)

Pear seeds have the same is-sueasappleseeds,sincetheyaresomewhatrelated.Again,eatinganoccasionalappleorpearseedisnotaproblem.