Batsusesonartohuntinsectsatnight.Somelizardshavetailsthatbreakoffandre

Adaptation

Batsusesonartohuntinsectsatnight.Somelizardshavetailsthatbreakoffandre‐growinafewmonths.Thewingsofcertainnon‐poisonousbutterflieslookexactlylikethoseoftheirpoisonousrelatives.Allthesestrangecharacteristicsaretheresultofoneimportantbiologicaltrait:adaptation.

Adaptationistheprocessbywhichorganisms—fromplantstoinsectstohumanbeings—adapttotheirenvironment.Theprocessenablesorganismsthatarebestsuitedtotheirenvironmenttosurvive.ThebetteranArcticfoxadaptstothefreezingtemperaturesintheArctic,forexample,thebetterhischancesareforsurvival.Similarly,thelesssunlightaspeciesoftreeneedsinajunglecrowdedwithtallertrees,themoresuccessfulthattreewillbe.Inordertosurvive,thetreewillneedtoadapttoitsshadyenvironment.

Adaptationscomeinthreemaintypes.Structuraladaptationsareonesyoucansee,likethesharpquillsthatpreventotherwiseslowandsmallporcupinesfrombeingeaten.Behavioraladaptationsconsistofbehaviorsthatspecieslearnedovertime,suchastheBlue‐FootedBoobiesontheGalapagosIslands,whoperformahigh‐steppingdanceduringmatingseason toshowofftheirbrightbluefeet.Finally,therearephysiologicaladaptations,whichallowspeciestoperformdifferentfunctions.Theproductionofvenombyasnake,forinstance,isanadaptationthatallowsittopoisonitspreywhenitbitesthem.

Lately,scientistshavebeentalkingalotaboutadaptation.Climatechangehascreatedsignificantchangesinourenvironment.Thepolaricecapsaremelting.Flowersarebloomingearlier.Lakesandriversaredryingup,causingdroughtsandforestfiresandpushinganimals

intocloserproximitywithhumanbeings.Climatechangehashadanegativeeffectonsomespecies,butapositiveeffectonothers.

Takethemountainpinebeetle.Thissmallblackbeetlehasdecimatedaround170,000squarekilometers(almost66,000squaremiles)ofpineforestinBritishColumbia,Canada.Fortyyearsago,themountainpinebeetlewasongoodtermswiththeforestsofNorthAmerican.Itlivedbelow9,000feet,abovewhichittendedtofreezetodeathduringthewinter.Butwarmerwinterscausedbyclimatechangehaveallowedittoexistatheightsofover11,000feet,wherewhitebarkpinesgrow.

Inthepast,whitebarkpinesneverhadtodealwithmountainpinebeetles.Asaresult,theyneverdevelopedawaytoprotectthemselvesagainstthem.Meanwhile,warmersummershavetrickedthemountainpinebeetleintoleavingtheirnestsandlayingeggstwomonthsaheadofschedule.Theiroffspringwindupinfestingawholenewcropofwhitebarkpinesbeforethesummerends.

Ifnothingisdonetoslowthespreadofthemountainpinebeetle,theymaywindupdestroyingeverywhitebarkpineinBritishColumbia.Thatis,unlessthepinefiguresoutawaytoadapttothebeetle’spresence.

Anotherreasonscientistsaretalkingaboutadaptationisduetotheriseininvasivespecies.Invasivespeciesarespeciesthathavetakenupresidenceinanenvironmentwheretheydonotbelong.Atthemoment,theBurmesepython—atypeofsnakenativetopartsofIndiaandSoutheastAsia—isaninvasivespeciesinthesouthofFlorida.TheBurmesepythoniswipingoutthepopulationofraccoons,possumsanddeerintheEverglades.ThatisbecausethesemammalsneverhadtoadapttothepresenceofBurmesepythons.

HowdidBurmesepythonswindupinFlorida?Somescientiststhinkpeoplewhokeepthesnakesaspetsreleasedthemintothewildyearsago,allowingthemtobreedandspreadthroughoutthestate.Howeverithappened,theremaynowbeover100,000BurmesepythonsintheEverglades.AndsincetheclimateinSouthFloridaissimilartothatofthesnake’snativehabitatinAsia,itisperfectlysuitedtotheenvironment.Therefore,itposesariskalltypesofspecieswholivethere—evendogsandcats.

Theriseinairtraveloverthelastfiftyyearshascausedspeciestobecomeestablishedinpartsoftheworldthatnaturedidnotintendthemtobe.Thecaseofthebrowntreesnakeonthe

islandofGuam,aterritoryoftheUnitedStatesinthemiddleofthePacificOcean,isonewell‐knownexample.BrowntreesnakesarenativetoAustraliaandPapuaNewGuinea.Atsomepoint,however,biologistsbelievetheysnuckintothecargoholdsofshipsormilitaryairplanesandhitchedaridetoGuam.

Initsnativearea,browntreesnakeseatbirds,lizards,bats,ratsandsmallrodents.Butanumberofnaturalpredatorshavealwayskeptitsnumbersdown.Withtheexceptionoftheoccasionalferalpigormangrovelizard,however,thebrowntreesnakehasnopredatorsinGuam.Thishasallowedittodevastatemostofthenativebirdspeciesontheisland.Andsincethesnakeshaveplentyofbirdsandothercritterstoeat,theyhavestartedtogrowlargerthantheirnormalsize.Thebrowntreesnake,inotherwords,isslowlyadaptingtoanewstyleof lifeonGuam.

Ofcourse,speciescanbethreatenedsimplybychangesintheweather.TheU.S.FishandWildlifeServicefirstplacedpolarbearsontheEndangeredSpeciesListin2008.WarmertemperaturesintheArctichavecausedmoreicetomelteachsummer,makingitharderforthemtosurvive.

Traditionally,polarbearsspendthewinterandspringmonthshuntingforsealsonicefloesintheocean.Duringthistimetheybulkupasmuchastheycan.Whentheicemeltsinthesummer,theymovetosolidlandandliveoffthereservesoffattheybuiltupallwinter.Whenfallarrives,theygatherneartheedgeofthesea,waitingfortheicetore‐form.Atthatpoint,theyventurebackoutandstarthuntingforseals.

TheproblemisthaticeisstartingtorunoutintheArctic.Itmeltsearlierandre‐formslatereachyear,forcingthepolarbeartosubsistoffenergyreservesforlongerperiods.Scientistsdescribeseeingrailthinpolarbearssittingonland,waitingandwaitingfortheicetoform.Mostbearslosearoundtwopoundseachdaythatthey’reonland.Someloseasmuchtwothirdsoftheirbodyweightduringthecourseofaseason.Forcomparison,thatwouldbelikeahealthy120‐poundwomandroppingdowntojust40poundsduringthesummermonths.Asaresult,thepopulationofpolarbearsinsomereachesofnorthernCanadahasdeclinedmorethantwentypercentoverthelasttwentyyears.

Theeffectofdisappearingicehasconsequencesforyoungergenerationsofpolarbears,too.Lean,sickly‐lookingpolarbearsgivebirthtosmallercubs,whichareunlikelytosurvivefor long.Andmotherpolarbearsweakenedbylackofsealmeathaveatoughtimecaringfortheiroffspring,whichalsomakesittoughfornewbornstosurvive.Infact,duetotherapiddecline

inthepolarbearpopulation,anewkindoftourismhaspoppedup,knownas“LastChanceTourism.”PeoplearestartingtotraveltoremoteregionsoftheArcticnotjusttophotographpolarbears,buttogetalookatthembeforetheydisappear.

Whateffectdoesthedecreasingpopulationofpolarbearshaveonotherspecies?Well,fewerpolarbearstopreyuponsealsmeansanuptickinthenumberofseals.Butitalsomeansthatpolarbears—previouslynomadic,isolatedanimals—arestartingtoencroachonhuman terrain.Starvingpolarbearsarebeingforcedtoraidgarbagecansintownsontheedgeofthetundra.Inthisway,theyarenotunlikegrizzlybearswanderingthroughacampsitescroungingforleftoverpizza.Assuch,theymaybedangerousforhumanslivingintheirvicinity.

Fortunately,manyanimals,plantsandinsectshavealreadybegunadaptingtoclimatechange.AccordingtoarecentstudypublishedinthejournalScience,manyspecieshaveadaptedtoincreasedglobaltemperaturesbymovingnorthorintohigherelevations.Overthelast40years,thecommabutterflyhasrelocatedfromcentralEnglandtothecityofEdinburgh,Scotland,adistanceofover130miles.(That’salongwayforabutterfly.)AsmallbirdnativetoEngland,knownasCetti'swarbler,hasmovedasimilardistance.

Andyetmanyspeciesareincapableofadaptingtosignificantchangesinclimate.Thisisbecausethosespecieshadadaptedtospecialized—or“niche”—environments.Oncetheenvironmentchanges,thesespeciescannothandlethehardshipandtypicallydieoff.

Thedisappearanceofanimalspeciesmayseemlikearemoteconcernforhumanbeings,atleastcomparedtothingslikewarandeconomiccollapse.Butwetendtoforgetthatallthingsareconnected.Asaresultofclimatechangeoceantemperaturesarerising.Warmeroceantemperaturesturnthewatermoreacidic.Andhigheracidityintheoceancausescoralreefstodie.

Over500speciesoffishliveinFlorida’scoralreefsalone.Ifreefsaroundtheworldstarttodieoff,sowillallthefish.Andaround75percentoftheworld’sfishcatchgetseatenbyhumanbeings.Somecountries,especiallyislandnations,relyalmostentirelyonfishfortheirdailydiet.Intheend,humansarealsogoingtohavetoadapttoourchangingenvironment.

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1.Adaptationenables species of animals to

Adeveloptraitsthat willonly affectonegenerationof thespecies

Bdeveloptraitsthatonlya fewmembersof thespecies willever have

Cdeveloptraitsthat willhelpthemsurviveintheirenvironments

Ddeveloptraitsthat willhelpthemchange theirenvironments

2.Whichofthefollowingisnotgivenas aneffectof climate andweatherchanges?

ABurmesepythons killingraccoons,possums,anddeer

Bmountainpinebeetles infestingwhite bark pines

Cpolarbears’ decreasedweight

Dthecomma butterfly relocatingtoScotland

3.Invasivespecies threatenthespecies oftheenvironment they havemovedto.Whichevidencefromthe textsupportsthis statement?

AThecomma butterfly has relocatedfromEnglandtoScotland.

BMountainpinebeetles thatareabletoliveathigherelevations areinfestingwhitebark pines.

CPolarbears forcedtoraidtowns ontheedge of thetundra lookingforfoodmaybe a threatto humans livingthere.

DBrowntreesnakes thathavebeentransportedtoGuamhavedevastatedmostof thenativebirdspecies ontheisland.

4.Thepassagesuggests that

Aallspecies of animals areindangerbecause of climatechange

Bsomespecies of animals areindangerbecause of climatechange

Cmostanimalsareunabletoadapttochanges intheirenvironment

Dinvasivespecies endupimprovingthe environments whichthey moveto

5.Themainideaofthis passageis

Asomeanimalscanadaptinordertosurvivechanges totheirenvironment

Bscientists andenvironmentalistshaveanimportanttaskinreversingclimatechange

Cclimatechangehascausedthedisappearance of toomanyspecies

Dadaptationusually has negativeconsequences foranimalspecies

6.Paragraph5 begins,“Takethemountainpinebeetle.” Theauthoruses this sentencetoindicatethathe

Awouldlikethereadertotakehome a mountainpinebeetle

Bwillnextdiscussthemountainpinebeetle

Cdesires scientists tomoveforwardonwork withthe mountainpinebeetle

Dhas finisheddiscussingthemountainpinebeetle

7.Choosetheanswerthatbestcompletes thesentence below.

climatechangeandinvasivespecies putdifferentanimalspecies atrisk,animals do have a chancetosurviveifthey canadapt.

ABut

BSo

CForexample

DWhile

8.Whichsnakeis originallyfromIndiaandsoutheastAsiabuthas nowadaptedtolivewithgreatsuccess insouthFlorida?

9.Why hasitbeensoeasy fortheBurmesepythonto adapttolife inFlorida eventhoughthenaturalhome of theBurmesepythonis sofaraway fromFlorida?

10.Explainwhetheronespecies canbenefitfromthe inability of anotherspecies toadaptto its changingenvironment.Useevidencefromthe texttosupportyouranswer.