endangered species | National Geographic Society

An endangered species is a type of organism that is threatened by extinction. Species become endangered for two main reasons: loss of habitat ... Skiptocontent Donate Account Menu Close Account ThisliststhelogosofprogramsorpartnersofNGEducationwhichhaveprovidedorcontributedthecontentonthispage. Poweredby Twitter Facebook Pinterest GoogleClassroom Email Print EncyclopedicEntry Vocabulary SelectTextLevel: 3rdGrade 6thGrade 8thGrade 12thGrade Anendangeredspeciesisatypeoforganismthatisthreatenedbyextinction.Speciesbecomeendangeredfortwomainreasons:lossofhabitatandlossofgeneticvariation.LossofHabitatAlossofhabitatcanhappennaturally.Dinosaurs,forinstance,losttheirhabitatabout65millionyearsago.Thehot,dryclimateoftheCretaceousperiodchangedveryquickly,mostlikelybecauseofanasteroidstrikingtheEarth.Theimpactoftheasteroidforceddebrisintotheatmosphere,reducingtheamountofheatandlightthatreachedEarth’ssurface.Thedinosaurswereunabletoadapttothisnew,coolerhabitat.Dinosaursbecameendangered,thenextinct.Humanactivitycanalsocontributetoalossofhabitat.Developmentforhousing,industry,andagriculturereducesthehabitatofnativeorganisms.Thiscanhappeninanumberofdifferentways.Developmentcaneliminatehabitatandnativespeciesdirectly.IntheAmazonrainforestofSouthAmerica,developershaveclearedhundredsofthousandsofacres.To“clear”apieceoflandistoremovealltreesandvegetationfromit.TheAmazonrainforestisclearedforcattleranches,logging,andurbanuse.Developmentcanalsoendangerspeciesindirectly.Somespecies,suchasfigtreesoftherainforest,mayprovidehabitatforotherspecies.Astreesaredestroyed,speciesthatdependonthattreehabitatmayalsobecomeendangered.Treecrownsprovidehabitatinthecanopy,ortoplayer,ofarainforest.Plantssuchasvines,fungisuchasmushrooms,andinsectssuchasbutterfliesliveintherainforestcanopy.Sodohundredsofspeciesoftropicalbirdsandmammalssuchasmonkeys.Astreesarecutdown,thishabitatislost.Specieshavelessroomtoliveandreproduce.Lossofhabitatmayhappenasdevelopmenttakesplaceinaspeciesrange.Manyanimalshavearangeofhundredsofsquarekilometers.ThemountainlionofNorthAmerica,forinstance,hasarangeofupto1,000squarekilometers(386squaremiles).Tosuccessfullyliveandreproduce,asinglemountainlionpatrolsthismuchterritory.Urbanareas,suchasLosAngeles,California,andVancouver,BritishColumbia,Canada,grewrapidlyduringthe20thcentury.Astheseareasexpandedintothewilderness,themountainlion’shabitatbecamesmaller.Thatmeansthehabitatcansupportfewermountainlions.BecauseenormouspartsoftheSierraNevada,Rocky,andCascademountainrangesremainundeveloped,however,mountainlionsarenotendangered.Lossofhabitatcanalsoleadtoincreasedencountersbetweenwildspeciesandpeople.Asdevelopmentbringspeopledeeperintoaspeciesrange,theymayhavemoreexposuretowildspecies.Poisonousplantsandfungimaygrowclosertohomesandschools.Wildanimalsarealsospottedmorefrequently.Theseanimalsaresimplypatrollingtheirrange,butinteractionwithpeoplecanbedeadly.Polarbears,mountainlions,andalligatorsareallpredatorsbroughtintoclosecontactwithpeopleastheylosetheirhabitattohomes,farms,andbusinesses.Aspeoplekillthesewildanimals,throughpesticides,accidentssuchascollisionswithcars,orhunting,nativespeciesmaybecomeendangered. LossofGeneticVariationGeneticvariationisthediversityfoundwithinaspecies.It’swhyhumanbeingsmayhaveblond,red,brown,orblackhair.Geneticvariationallowsspeciestoadapttochangesintheenvironment.Usually,thegreaterthepopulationofaspecies,thegreateritsgeneticvariation.Inbreedingisreproductionwithclosefamilymembers.Groupsofspeciesthathaveatendencytoinbreedusuallyhavelittlegeneticvariation,becausenonewgeneticinformationisintroducedtothegroup.Diseaseismuchmorecommon,andmuchmoredeadly,amonginbredgroups.Inbredspeciesdonothavethegeneticvariationtodevelopresistancetothedisease.Forthisreason,feweroffspringofinbredgroupssurvivetomaturity.Lossofgeneticvariationcanoccurnaturally.CheetahsareathreatenedspeciesnativetoAfricaandAsia.Thesebigcatshaveverylittlegeneticvariation.Biologistssaythatduringthelasticeage,cheetahswentthroughalongperiodofinbreeding.Asaresult,thereareveryfewgeneticdifferencesbetweencheetahs.Theycannotadapttochangesintheenvironmentasquicklyasotheranimals,andfewercheetahssurvivetomaturity.Cheetahsarealsomuchmoredifficulttobreedincaptivitythanotherbigcats,suchaslions.Humanactivitycanalsoleadtoalossofgeneticvariation.Overhuntingandoverfishinghavereducedthepopulationsofmanyanimals.Reducedpopulationmeanstherearefewerbreedingpairs.Abreedingpairismadeupoftwomaturemembersofthespeciesthatarenotcloselyrelatedandcanproducehealthyoffspring.Withfewerbreedingpairs,geneticvariationshrinks.Monoculture,theagriculturalmethodofgrowingasinglecrop,canalsoreducegeneticvariation.Modernagribusinessreliesonmonocultures.Almostallpotatoescultivated,sold,andconsumed,forinstance,arefromasinglespecies,theRussetBurbank.Potatoes,nativetotheAndesMountainsofSouthAmerica,havedozensofnaturalvarieties.Thegeneticvariationofwildpotatoesallowsthemtoadapttoclimatechangeanddisease.ForRussetBurbanks,however,farmersmustusefertilizersandpesticidestoensurehealthycropsbecausetheplanthasalmostnogeneticvariation.Plantbreedersoftengobacktowildvarietiestocollectgenesthatwillhelpcultivatedplantsresistpestsanddrought,andadapttoclimatechange.However,climatechangeisalsothreateningwildvarieties.Thatmeansdomesticatedplantsmayloseanimportantsourceoftraitsthathelpthemovercomenewthreats.TheRedListTheInternationalUnionforConservationofNature(IUCN)keepsa“RedListofThreatenedSpecies.”TheRedListdefinestheseverityandspecificcausesofaspecies’threatofextinction.TheRedListhassevenlevelsofconservation:leastconcern,nearthreatened,vulnerable,endangered,criticallyendangered,extinctinthewild,andextinct.Eachcategoryrepresentsadifferentthreatlevel.Speciesthatarenotthreatenedbyextinctionareplacedwithinthefirsttwocategories—leastconcernandnear-threatened.Thosethataremostthreatenedareplacedwithinthenextthreecategories,knownasthethreatenedcategories—vulnerable,endangered,andcriticallyendangered.Thosespeciesthatareextinctinsomeformareplacedwithinthelasttwocategories—extinctinthewildandextinct.Classifyingaspeciesasendangeredhastodowithitsrangeandhabitat,aswellasitsactualpopulation.Forthisreason,aspeciescanbeofleastconcerninoneareaandendangeredinanother.Thegraywhale,forinstance,hasahealthypopulationintheeasternPacificOcean,alongthecoastofNorthandSouthAmerica.ThepopulationinthewesternPacific,however,iscriticallyendangered. LeastConcernLeastconcernisthelowestlevelofconservation.Aspeciesofleastconcernisonethathasawidespreadandabundantpopulation.Humanbeingsareaspeciesofleastconcern,alongwithmostdomesticanimals,suchasdogsandcats.Manywildanimals,suchaspigeonsandhouseflies,arealsoclassifiedasleastconcern.NearThreatenedAnearthreatenedspeciesisonethatislikelytoqualifyforathreatenedcategoryinthenearfuture.Manyspeciesofviolets,nativetotropicaljunglesinSouthAmericaandAfrica,arenearthreatened,forinstance.Theyhavehealthypopulations,buttheirrainforesthabitatisdisappearingatafastpace.Peoplearecuttingdownhugeareasofrainforestfordevelopmentandtimber.Manyvioletspeciesarelikelytobecomethreatened.VulnerableSpeciesThedefinitionsofthethreethreatenedcategories(vulnerable,endangered,andcriticallyendangered)arebasedonfivecriteria:populationreductionrate,geographicrange,populationsize,populationrestrictions,andprobabilityofextinction.Threatenedcategorieshavedifferentthresholdsforthesecriteria.Asthepopulationandrangeofthespeciesdecreases,thespeciesbecomesmorethreatened.1)PopulationreductionrateAspeciesisclassifiedasvulnerableifitspopulationhasdeclinedbetween30and50percent.Thisdeclineismeasuredover10yearsorthreegenerationsofthespecies,whicheverislonger.Agenerationistheperiodoftimebetweenthebirthofananimalandthetimeitisabletoreproduce.Miceareabletoreproducewhentheyareaboutonemonthold.Mousepopulationsaremostlytrackedover10-yearperiods.Anelephant'sgenerationlastsabout15years.So,elephantpopulationsaremeasuredover45-yearperiods.Aspeciesisvulnerableifitspopulationhasdeclinedatleast50percentandthecauseofthedeclineisknown.Habitatlossistheleadingknowncauseofpopulationdecline.Aspeciesisalsoclassifiedasvulnerableifitspopulationhasdeclinedatleast30percentandthecauseofthedeclineisnotknown.Anew,unknownvirus,forexample,couldkillhundredsoreventhousandsofindividualsbeforebeingidentified.2)GeographicrangeAspeciesisvulnerableifits“extentofoccurrence”isestimatedtobelessthan20,000squarekilometers(7,722squaremiles).Anextentofoccurrenceisthesmallestareathatcouldcontainallsitesofaspecies’population.Ifallmembersofaspeciescouldsurviveinasinglearea,thesizeofthatareaisthespecies’extentofoccurrence.Aspeciesisalsoclassifiedasvulnerableifits“areaofoccupancy”isestimatedtobelessthan2,000squarekilometers(772squaremiles).Anareaofoccupancyiswhereaspecificpopulationofthatspeciesresides.Thisareaisoftenabreedingornestingsiteinaspeciesrange. 3)PopulationsizeSpecieswithfewerthan10,000matureindividualsarevulnerable.Thespeciesisalsovulnerableifthatpopulationdeclinesbyatleast10percentwithin10yearsorthreegenerations,whicheverislonger.4)PopulationrestrictionsPopulationrestrictionisacombinationofpopulationandareaofoccupancy.Aspeciesisvulnerableifitisrestrictedtolessthan1,000matureindividualsoranareaofoccupancyoflessthan20squarekilometers(8squaremiles).5)Probabilityofextinctioninthewildisatleast10percentwithin100years.Biologists,anthropologists,meteorologists,andotherscientistshavedevelopedcomplexwaystodetermineaspecies’probabilityofextinction.Theseformulascalculatethechancesaspeciescansurvive,withouthumanprotection,inthewild.VulnerableSpecies:EthiopianBananaFrogTheEthiopianbananafrog(Afrixalusenseticola)isasmallfrognativetohigh-altitudeareasofsouthernEthiopia.Itisavulnerablespeciesbecauseitsareaofoccupancyislessthan2,000squarekilometers(772squaremiles).Theextentandqualityofitsforesthabitatareindecline.Threatstothishabitatincludeforestclearance,mostlyforhousingandagriculture.VulnerableSpecies:SnaggletoothSharkThesnaggletoothshark(Hemipristiselongatus)isfoundinthetropical,coastalwatersoftheIndianandPacificOceans.Itsareaofoccupancyisenormous,fromsoutheastAfricatothePhilippines,andfromChinatoAustralia.However,thesnaggletoothsharkisavulnerablespeciesbecauseofaseverepopulationreductionrate.Itspopulationhasfallenmorethan10percentover10years.Thenumberofsharksisdecliningduetofisheries,especiallyintheJavaSeaandGulfofThailand.Thesnaggletoothshark’sflesh,fins,andliverareconsideredhigh-qualityfoods.Theyaresoldincommercialfishmarkets,aswellasrestaurants.VulnerableSpecies:GalapagosKelpGalapagoskelp(Eiseniagalapagensis)isatypeofseaweedonlyfoundneartheGalapagosIslandsinthePacificOcean.Galapagoskelpisclassifiedasvulnerablebecauseitspopulationhasdeclinedmorethan10percentover10years.ClimatechangeistheleadingcauseofdeclineamongGalapagoskelp.ElNino,thenaturalweatherpatternthatbringsunusuallywarmwatertotheGalapagos,istheleadingagentofclimatechangeinthisarea.Galapagoskelpisacold-waterspeciesanddoesnotadaptquicklytochangesinwatertemperature. EndangeredSpecies1)PopulationreductionrateAspeciesisclassifiedasendangeredwhenitspopulationhasdeclinedbetween50and70percent.Thisdeclineismeasuredover10yearsorthreegenerationsofthespecies,whicheverislonger.Aspeciesisclassifiedasendangeredwhenitspopulationhasdeclinedatleast70percentandthecauseofthedeclineisknown.Aspeciesisalsoclassifiedasendangeredwhenitspopulationhasdeclinedatleast50percentandthecauseofthedeclineisnotknown.2)GeographicrangeAnendangeredspecies’extentofoccurrenceislessthan5,000squarekilometers(1,930squaremiles).Anendangeredspecies’areaofoccupancyislessthan500squarekilometers(193squaremiles).3)PopulationsizeAspeciesisclassifiedasendangeredwhentherearefewerthan2,500matureindividuals.Whenaspeciespopulationdeclinesbyatleast20percentwithinfiveyearsortwogenerations,itisalsoclassifiedasendangered.4)PopulationrestrictionsAspeciesisclassifiedasendangeredwhenitspopulationisrestrictedtolessthan250matureindividuals.Whenaspecies’populationisthislow,itsareaofoccupancyisnotconsidered.5)Probabilityofextinctioninthewildisatleast20percentwithin20yearsorfivegenerations,whicheverislonger.EndangeredSpecies:SiberianSturgeonTheSiberiansturgeon(Acipenserbaerii)isalargefishfoundinriversandlakesthroughouttheSiberianregionofRussia.TheSiberiansturgeonisabenthicspecies.Benthicspeciesliveatthebottomofabodyofwater.TheSiberiansturgeonisanendangeredspeciesbecauseitstotalpopulationhasdeclinedbetween50and80percentduringthepast60years(threegenerationsofsturgeon).Overfishing,poaching,anddamconstructionhavecausedthisdecline.Pollutionfromminingactivitieshasalsocontributedtoabnormalitiesinthesturgeon’sreproductivesystem.EndangeredSpecies:TahitiReed-warblerTheTahitireed-warbler(Acrocephaluscaffer)isasongbirdfoundonthePacificislandofTahiti.Itisanendangeredspeciesbecauseithasaverysmallpopulation.Thebirdisonlyfoundonasingleisland,meaningbothitsextentofoccurrenceandareaofoccupancyareverysmall.TheTahitireed-warblerisalsoendangeredbecauseofhumanactivity.ThetropicalweedMiconiaisanon-nativespeciesthathastakenovermuchofTahiti’snativevegetation.Thereed-warblerlivesalmostexclusivelyinTahiti’sbambooforests.Thebirdnestsinbambooandfeedsonflowersandinsectsthatlivethere.AsdevelopmentandinvasivespeciessuchasMiconiadestroythebambooforests,thepopulationofTahitireed-warblerscontinuestoshrink. EndangeredSpecies:EbonyEbony(Diospyroscrassiflora)isatreenativetotherainforestsofcentralAfrica,includingCongo,Cameroon,andGabon.Ebonyisanendangeredspeciesbecausemanybiologistscalculateitsprobabilityofextinctioninthewildisatleast20percentwithinfivegenerations.Ebonyisthreatenedduetooverharvesting.Ebonytreesproduceaveryheavy,darkwood.Whenpolished,ebonycanbemistakenforblackmarbleorotherstone.Forcenturies,ebonytreeshavebeenharvestedforfurnitureandsculpturalusessuchaschesspieces.Mostebony,however,isharvestedtomakemusicalinstrumentssuchaspianokeysandthefingerboardsofstringedinstruments.CriticallyEndangeredSpecies1)PopulationreductionrateAcriticallyendangeredspecies’populationhasdeclinedbetween80and90percent.Thisdeclineismeasuredover10yearsorthreegenerationsofthespecies,whicheverislonger.Aspeciesisclassifiedascriticallyendangeredwhenitspopulationhasdeclinedatleast90percentandthecauseofthedeclineisknown.Aspeciesisalsoclassifiedasendangeredwhenitspopulationhasdeclinedatleast80percentandthecauseofthedeclineisnotknown.2)GeographicrangeAcriticallyendangeredspecies’extentofoccurrenceislessthan100squarekilometers(39squaremiles).Acriticallyendangeredspecies’areaofoccupancyisestimatedtobelessthan10squarekilometers(4squaremiles).3)PopulationsizeAspeciesisclassifiedascriticallyendangeredwhentherearefewerthan250matureindividuals.Aspeciesisalsoclassifiedascriticallyendangeredwhenthenumberofmatureindividualsdeclinesbyatleast25percentwithinthreeyearsoronegeneration,whicheverislonger.4)PopulationrestrictionsAspeciesisclassifiedascriticallyendangeredwhenitspopulationisrestrictedtolessthan50matureindividuals.Whenaspecies’populationisthislow,itsareaofoccupancyisnotconsidered.5)Probabilityofextinctioninthewildisatleast50percentwithin10yearsorthreegenerations,whicheverislonger.CriticallyEndangeredSpecies:BolivianChinchillaRatTheBolivianchinchillarat(Abrocomaboliviensis)isarodentfoundinasmallsectionoftheSantaCruzregionofBolivia.Itiscriticallyendangeredbecauseitsextentofoccurrenceislessthan100squarekilometers(39squaremiles).Themajorthreattothisspeciesislossofitscloudforesthabitat.Peopleareclearingforeststocreatecattlepastures. CriticallyEndangeredSpecies:TranscaucasianRacerunnerTheTranscaucasianracerunner(Eremiaspleskei)isalizardfoundontheArmenianPlateau,locatedinArmenia,Azerbaijan,Iran,andTurkey.TheTranscaucasianracerunnerisacriticallyendangeredspeciesbecauseofahugepopulationdecline,estimatedatmorethan80percentduringthepast10years.Threatstothisspeciesincludethesalination,orincreasedsaltiness,ofsoil.Fertilizersusedforagriculturaldevelopmentseepintothesoil,increasingitssaltiness.Racerunnersliveinandamongtherocksandsoil,andcannotadapttotheincreasedsaltintheirfoodandshelter.Theracerunnerisalsolosinghabitataspeoplecreatetrashdumpsontheirareaofoccupancy.CriticallyEndangeredSpecies:WhiteFerulaMushroomThewhiteferulamushroom(Pleurotusnebrodensis)isacriticallyendangeredspeciesoffungus.Themushroomiscriticallyendangeredbecauseitsextentofoccurrenceislessthan100squarekilometers(39squaremiles).ItisonlyfoundinthenorthernpartoftheItalianislandofSicily,intheMediterraneanSea.Theleadingthreatstowhiteferulamushroomsarelossofhabitatandoverharvesting.Whiteferulamushroomsareagourmetfooditem.Farmersandamateurmushroomhuntersharvestthefungusforfoodandprofit.Themushroomscanbesoldforupto$100perkilogram(2.2pounds).ExtinctInTheWildAspeciesisextinctinthewildwhenitonlysurvivesincultivation(plants),incaptivity(animals),orasapopulationwelloutsideitsestablishedrange.Aspeciesmaybelistedasextinctinthewildonlyafteryearsofsurveyshavefailedtorecordanindividualinitsnativeorexpectedhabitat.ExtinctintheWild:Scimitar-hornedOryxThescimitar-hornedoryx(Oryxdammah)isaspeciesofantelopewithlonghorns.ItsrangeextendsacrossnorthernAfrica.Thescimitar-hornedoryxislistedasextinctinthewildbecausethelastconfirmedsightingofonewasin1988.Overhuntingandhabitatloss,includingcompetitionwithdomesticlivestock,arethemainreasonsfortheextinctionoftheoryx’swildpopulation.CaptiveherdsarenowkeptinprotectedareasofTunisia,Senegal,andMorocco.Scimitar-hornedoryxesarealsofoundinmanyzoos.ExtinctintheWild:BlackSoft-shellTurtleTheblacksoft-shellturtle(Nilssonianigricans)isafreshwaterturtlethatexistsonlyinoneman-madepond,attheBaizidBostamiShrinenearChittagong,Bangladesh.The150to300turtlesthatliveatthepondrelyentirelyonhumansforfood.Until2000,blacksoft-shellturtleslivedthroughoutthewetlandsoftheBrahmaputraRiver,feedingmostlyonfreshwaterfish.Unlikeotheranimalsthatareextinctinthewild,blacksoft-shellturtlesarenotfoundinmanyzoos.Theshrine’scaretakersdonotallowanyone,includingscientists,totaketheturtles.Thereptilesareconsideredtobethedescendantsofpeoplewhoweremiraculouslyturnedintoturtlesbyasaintduringthe13thcentury. ExtinctintheWild:Mt.KaalaCyaneaTheMt.Kaalacyanea(Cyaneasuperba)isalarge,floweringtreenativetotheislandofOahu,intheU.S.stateofHawaii.TheMt.Kaalacyaneahaslarge,broadleavesandfleshyfruit.Thetreeisextinctinthewildlargelybecauseofinvasivespecies.Non-nativeplantscrowdedthecyaneaoutofitshabitat,andnon-nativeanimalssuchaspigs,rats,andslugsateitsfruitmorequicklythanitcouldreproduce.Mt.Kaalacyaneatreessurviveintropicalnurseriesandbotanicalgardens.Manybotanistsandconservationistslookforwardtoestablishinganewpopulationinthewild.ExtinctAspeciesisextinctwhenthereisnoreasonabledoubtthatthelastremainingindividualofthatspecieshasdied.Extinct:CubanMacawTheCubanmacaw(Aratricolor)wasatropicalparrotnativetoCubaandasmallCubanisland,IsladelaJuventud.Huntingandcollectingthebirdsforpetsledtothebird’sextinction.ThelastspecimenoftheCubanmacawwascollectedin1864.Extinct:Ridley’sStickInsectRidley’sstickinsect(Pseudobactriciaridleyi)wasnativetothetropicaljungleoftheislandofSingapore.Thisinsect,whoselong,segmentedbodyresembledatreelimb,isonlyknownthroughasinglespecimen,collectedmorethan100yearsago.Duringthe20thcentury,Singaporeexperiencedrapiddevelopment.Almosttheentirejunglewascleared,deprivingtheinsectofitshabitat.Extinct:SriLankanLegumeTreeTheSriLankanlegumetree(Crudiazeylanica),nativeonlytotheislandofSriLankaintheIndianOcean,wasagiantspeciesoflegume.Peasandpeanutsaresmallertypesoflegumes.Habitatlossfromdevelopmentinthe20thcenturyisthemainreasonthetreewentextinctinthewild.AsinglespecimensurvivedattheRoyalBotanicalGardeninPeradeniya,SriLanka,until1990,whenthat,too,waslost. EndangeredSpeciesandPeopleWhenaspeciesisclassifiedasendangered,governmentsandinternationalorganizationscanworktoprotectit.Lawsmaylimithuntinganddestructionofthespecies’habitat.Individualsandorganizationsthatbreaktheselawsmayfacehugefines.Becauseofsuchactions,manyspecieshaverecoveredfromtheirendangeredstatus.Thebrownpelicanwastakenofftheendangeredspecieslistin2009,forinstance.ThisseabirdisnativetothecoastsofNorthAmericaandSouthAmerica,aswellastheislandsoftheCaribbeanSea.ItisthestatebirdoftheU.S.stateofLouisiana.In1970,thenumberofbrownpelicansinthewildwasestimatedat10,000.Thebirdwasclassifiedasvulnerable.Duringthe1970sand1980s,governmentsandconservationgroupsworkedtohelpthebrownpelicanrecover.Youngchickswererearedinhatchingsites,thenreleasedintothewild.Humanaccesstonestingsiteswasseverelyrestricted.ThepesticideDDT,whichdamagedtheeggsofthebrownpelican,wasbanned.Duringthe1980s,thenumberofbrownpelicanssoared.In1988,theIUCN“delisted”thebrownpelican.Thebird,whosepopulationisnowinthehundredsofthousands,isnowinthecategoryofleastconcern. Unlikemanyendangeredspecies,therearestillmoregiantpandasinthewildthanthereareinzoos. PhotographbyBrandonBeccarelli,YourShot LonesomeGeorgeUntil2012,LonesomeGeorgewasthemostendangeredspeciesontheplanet.HewastheonlylivingspeciesofPintaIslandtortoiseknowntoexist.ThePintaIslandtortoisewasonlyfoundonPinta,oneoftheGalapagosIslands.TheCharlesDarwinResearchStation,ascientificfacilityintheGalapagos,offereda$10,000rewardtoanyzooorindividualforlocatingasinglePintaIslandtortoisefemale.OnJune25,2012,LonesomeGeorgedied,leavingonemoreextinctspeciesintheworld. ConventiononBiologicalDiversityTheConventiononBiologicalDiversityisaninternationaltreatytosustainandprotectthediversityoflifeonEarth.Thisincludesconservation,sustainability,andsharingthebenefitsofgeneticresearchandresources.TheConventiononBiologicalDiversityhasadoptedtheIUCNRedListofendangeredspeciesinordertomonitorandresearchspecies'populationandhabitats.ThreenationshavenotratifiedtheConventiononBiologicalDiversity:Andorra,theHolySee(Vatican),andtheUnitedStates. abnormality Noun deformityorconditiondifferentfromthenormalorexpectedstateofbeing. abundant Adjective inlargeamounts. adapt Verb toadjusttonewsurroundingsoranewsituation. agribusiness Noun thestrategyofapplyingprofit-makingpracticestotheoperationoffarmsandranches. agriculture Noun theartandscienceofcultivatinglandforgrowingcrops(farming)orraisinglivestock(ranching). altitude Noun thedistanceabovesealevel. antelope Noun grazingmammal. anthropology Noun scienceoftheorigin,development,andcultureofhumanbeings. areaofoccupancy Noun geographicareawhereaspecificpopulationofaspeciesresides,usedtodetermineaspecies'levelofconservation. asteroid Noun irregularlyshapedplanetarybody,rangingfrom6meters(20feet)to933kilometers(580miles)indiameter,orbitingthesunbetweenMarsandJupiter. atmosphere Noun layersofgasessurroundingaplanetorothercelestialbody. bamboo Noun typeofhuge,woodygrass. ban Verb toprohibitornotallow. benthic Adjective havingtodowiththebottomofadeepbodyofwater. bigcat Noun largepredators,includingtigers,lions,jaguars,andleopards. biologist Noun scientistwhostudieslivingorganisms. botanicalgarden Noun placewhereplantsandflowersaregrownanddisplayedforeducationandstudy. breedincaptivity Verb tomateanimalsinacontrolledenvironment. breedingpair Noun animalswhocooperateoveraperiodoftimetoproducegenerationsofoffspring. calculate Verb toreachaconclusionbymathematicalorlogicalmethods. canopy Noun oneofthetoplayersofaforest,formedbythethickleavesofverytalltrees. cattlepasture Noun largeareaofgrasslandwherecattlegraze. cattleranch Noun largefarmwherecattleareraisedandbredformeatorleather. cheetah Noun large,spottedcatnativetoAfrica. chess Noun gameofstrategyplayedbytwoplayers,eachwith16piecesmovedacrossacheckeredboard. chinchilla Noun rodentnativetoSouthAmerica. classify Verb toidentifyorarrangebyspecifictypeorcharacteristic. climate Noun allweatherconditionsforagivenlocationoveraperiodoftime. climatechange Noun gradualchangesinalltheinterconnectedweatherelementsonourplanet. cloudforest Noun woodedarea,usuallyhigh-altitude,almostalwayscoveredbycloudsandfog. coast Noun edgeoflandalongtheseaorotherlargebodyofwater. conservation Noun managementofanaturalresourcetopreventexploitation,destruction,orneglect. ConventiononBiologicalDiversity Noun internationaltreatytosustainandprotectthediversityoflifeonEarth. Cretaceousperiod Noun 145millionto65millionyearsago.Theperiodendedwithextinctionofthedinosaursandtheriseofmammals. criticallyendangered Noun levelofconservationbetween"endangered"and"extinctinthewild." crop Noun agriculturalproduce. cultivate Verb toencouragethegrowthofsomethingthroughworkandattention. cyanea Noun typeofplantnativetoHawaiiwithlarge,broadleaves. dam Noun structurebuiltacrossariverorotherwaterwaytocontroltheflowofwater. DDT Noun (dichloro-diphenyl-trichloroethane)toxicchemicalusedasaninsecticidebutillegalformostusesintheU.S.since1972. debris Noun remainsofsomethingbrokenordestroyed;waste,orgarbage. decline Verb toreduceorgodowninnumber. descendant Noun children,grandchildren,andotheroffspring. development Noun constructionorpreparationoflandforhousing,industry,oragriculture. dinosaur Noun verylarge,extinctreptilechieflyfromtheMesozoicEra,251millionto65millionyearsago. diversity Noun difference. domesticanimal Noun animalthathasbeentamedforworkortobeapet. dwarf Verb tomakesomethingappearsmallbyhavingitappearnexttosomethingmuchlarger. ebony Noun treenativetoAfricathatproducesdark,hardtimber. eliminate Verb toremove. ElNiño Noun irregular,recurringweathersystemthatfeaturesawarm,eastern-flowingoceancurrentintheeasternPacificOcean. encounter Verb tomeet,especiallyunexpectedly. endangeredspecies Noun organismthreatenedwithextinction. enormous Adjective verylarge. extentofoccurrence Noun smallestareathatcouldcontainallthesitesofaspecies'population,usedtodetermineaspecieslevelofconservation. extinct Adjective nolongerexisting. extinctinthewild Noun highestlevelofconservationofalivingspecies,whentheonlylivingmembersofthatspeciesareprotectedincaptivitysuchaszoosoraquariums. extinction Noun processofcompletedisappearanceofaspeciesfromEarth. farm Noun landcultivatedforcrops,livestock,orboth. fertilizer Noun nutrient-richchemicalsubstance(naturalormanmade)appliedtosoiltoencourageplantgrowth. fine Verb topunish,usuallybycharginganeconomicpenaltyorfee.Or,thepenaltyorfeeitself. fingerboard Noun flatpartofastringedinstrumentwherethemusicianpressesthestringdowntocreateanote. fishery Noun industryoroccupationofharvestingfish,eitherinthewildorthroughaquaculture. frequent Adjective often. fungi PluralNoun (singular:fungus)organismsthatsurvivebydecomposingandabsorbingnutrientsinorganicmaterialsuchassoilordeadorganisms. generation Noun groupinaspeciesmadeupofmembersthatareroughlythesameage. geneticvariation Noun differencesinthegenesamongindividualmembersofaspecies. gourmet Adjective high-quality,expensive,ordifficult-to-preparefood. habitat Noun environmentwhereanorganismlivesthroughouttheyearorforshorterperiodsoftime. hatch Verb toemergefromanegg. hippopotamus Noun largemammalnativetoAfricathatlivesnearrivers. iceage Noun longperiodofcoldclimatewhereglacierscoverlargepartsoftheEarth.Thelasticeagepeakedabout20,000yearsago.Alsocalledglacialage. impact Noun collisionorcrash. inbreed Verb toproduceoffspringwithclosefamilymembers. industry Noun activitythatproducesgoodsandservices. internationalorganization Noun unitmadeupofgovernmentsorgroupsindifferentcountries,usuallyforaspecificpurpose. InternationalUnionfortheConservationofNature(IUCN) Noun environmentalorganizationconcernedwithpreservingnaturalecosystemsandhabitats. invasivespecies Noun typeofplantoranimalthatisnotindigenoustoaparticularareaandcauseseconomicorenvironmentalharm. island Noun bodyoflandsurroundedbywater. jungle Noun tropicalecosystemfilledwithtreesandunderbrush. kelp Noun typeofseaweed. leastconcern Adjective lowestlevelofconservation,usedwhenthepopulationandhabitatofaspeciesarehealthy. legume Noun typeofplantwithapodthatsplits,withseedsinthemiddle,suchaspeanuts. levelofconservation Noun oneofsevencategoriesofaspecies'threatofextinction,assignedbytheInternationalUnionfortheConservationofNature:leastconcern,nearthreatened,vulnerable,endangered,criticallyendangered,extinctinthewild,andextinct. livestock Noun animalsraisedfor humanuse. logging Noun industryengagedincuttingdowntreesandmovingthewoodtosawmills. LonesomeGeorge Noun lastsurvivingPintaIslandtortoise. macaw Noun long-tailedparrotnativetotheAmericas. marble Noun typeofmetamorphicrock. mature Adjective adultmemberofaspecieswhoisabletoreproduce. meteorologist Noun personwhostudiespatternsandchangesinEarth'satmosphere. mining Noun processofextractingorefromtheEarth. monitor Verb toobserveandrecordbehaviorordata. monoculture Noun thesystemofgrowingonetypeofcrop. mountainlion Noun largecatnativetoNorthandSouthAmerica.Alsocalledacougar,puma,catamount,andpanther. mountainrange Noun seriesorchainofmountainsthatareclosetogether. nearthreatened Noun levelofconservationbetween"leastconcern"and"vulnerable." nestingsite Noun placewherebirdsbuildnestsandraisetheiryoung. non-nativespecies Noun atypeofplantoranimalthatisnotindigenoustoaparticulararea.Non-nativespeciescansometimescauseeconomicorenvironmentalharmasaninvasivespecies. offspring Noun thechildrenofapersonoranimal. oryx Noun antelopenativetoAfrica. overfish Verb toharvestaquaticlifetothepointwherespeciesbecomerareinthearea. overharvest Verb tousemoreofaresourcethancanbereplacednaturally. overhunt Verb tocaptureandkillenoughanimalstoreducetheirbreedingpopulationbelowsustainablelevels. parrot Noun typeofbirdwithalargebeak. patrol Verb tosurveyandmonitoranareabypassingthroughit. pelican Noun largemarinebirdwithabigbill. pesticide Noun naturalormanufacturedsubstanceusedtokillorganismsthatthreatenagricultureorareundesirable.Pesticidescanbefungicides(whichkillharmfulfungi),insecticides(whichkillharmfulinsects),herbicides(whichkillharmfulplants),orrodenticides(whichkillharmfulrodents.) pet Noun animalkeptasahelperorcompanion. pianokey Noun lever,eitherblackorwhite,whichtriggersahammertohitaspecificstringinsidethebodyofapiano. plateau Noun largeregionthatishigherthanthesurroundingareaandrelativelyflat. poach Verb tohunt,trap,orfishillegally. poisonous Adjective toxicorcontainingdangerouschemicals. pollution Noun introductionofharmfulmaterialsintotheenvironment. populationreductionrate Noun rateatwhichthenumbersofaspecificspeciesareshrinking. populationrestrictions Noun calculationofaspecies'populationanditsareaofoccupancythathelpsdetermineitsconservationstatus. probabilityofextinction Noun calculationofhowlongaspeciescansurvivewithouthumanprotection. racerunner Noun smalllizard. rainforest Noun areaoftall,mostlyevergreentreesandahighamountofrainfall. ratify Verb toformallyapproveorconfirm. RedList Noun listdefiningtheseverityandcausesofeachspecies'threatofextinction.TheRedListismaintainedbytheInternationalUnionfortheConservationofNature(IUCN). reduce Verb tolowerorlessen. reproduce Verb tocreateoffspring,bysexualorasexualmeans. reproductivesystem Noun organsinvolvedinanorganism'sreproduction. rodent Noun orderofmammalsoftencharacterizedbylongteethforgnawingandnibbling. RussetBurbank Noun large,brown-skinnedpotatooftenusedformakingfrenchfriesinfastfoodrestaurants. salination Noun processwheresoilsbuilduphighsaltcontent. scimitar Noun long,curvedswordwithasharpouteredge,developedintheMiddleEast. seabird Noun birdnativetoanaquaticenvironment. seaweed Noun marinealgae.Seaweedcanbecomposedofbrown,green,orredalgae,aswellas"blue-greenalgae,"whichisactuallybacteria. seep Verb toslowlyflowthroughaborder. severe Adjective harsh. shrine Noun placeofworshiporspiritualdevotion. soil Noun toplayeroftheEarth'ssurfacewhereplantscangrow. songbird Noun birdwitharecognizablevocalpattern. speciesrange Noun native,geographicareainwhichanorganismcanbefound.Rangealsoreferstothegeographicdistributionofaparticularspecies. specimen Noun individualorganismthatisatypicalexampleofitsclassification. sturgeon Noun typeofmarineorfreshwaterlarge,long,bonyfish. sustainability Noun useofresourcesinsuchamannerthattheywillneverbeexhausted. tendency Noun habitorpredictablewayofbehaving. threatenedcategories Noun threelevelsofendangeredspecies:vulnerable,endangered,andcriticallyendangered. threatenedspecies Noun organismthatmaysoonbecomeendangered. threshold Noun pointinaprocessthatmustbemettostartanewstageintheprocess. timber Noun woodinanunfinishedform,eithertreesorlogs. tortoise Noun land-basedturtle,usuallywithatall,roundedshell. treecrown Noun topbranchesofatree. tropical Adjective existinginthetropics,thelatitudesbetweentheTropicofCancerinthenorthandtheTropicofCapricorninthesouth. turtle Noun typeofreptilewithashellencasingmostofitsbody. urbanarea Noun developed,denselypopulatedareawheremostinhabitantshavenonagriculturaljobs. vegetation Noun alltheplantlifeofaspecificplace. violet Noun plantwithsmallflowers. virus Noun pathogenicagent thatlivesandmultipliesinalivingcell. vulnerablespecies Noun levelofconservationbetween"nearthreatened"and"endangered."Vulnerableisthelowestofthe"threatened"categories. warbler Noun typeofsmallsongbird. weatherpattern Noun repeatingorpredictablechangesintheEarth'satmosphere,suchaswinds,precipitation,andtemperatures. weed Noun unwantedplant. wetland Noun areaoflandcoveredbyshallowwaterorsaturatedbywater. zoo Noun placewhereanimalsarekeptforexhibition. Audio&Video IUCN:HowtoSearchtheRedList Interactives NationalGeographicMagazine:EndangeredSpeciesPhotoMap Websites SmithsonianNationalZoologicalPark:EndangeredSpeciesScience U.S.Fish&WildlifeService:EndangeredSpeciesProgram IUCN:RedListofThreatenedSpecies Credits MediaCredits Theaudio,illustrations,photos,andvideosarecreditedbeneaththemediaasset,exceptforpromotionalimages,whichgenerallylinktoanotherpagethatcontainsthemediacredit.TheRightsHolderformediaisthepersonorgroupcredited. Writers KimRutledge TaraRamroop DianeBoudreau MelissaMcDaniel SantaniTeng ErinSprout HilaryCosta HilaryHall JeffHunt Illustrators MaryCrooks,NationalGeographicSociety TimGunther Editors JeannieEvers,EmdashEditing KaraWest EducatorReviewer NancyWynne Producer Caryl-Sue,NationalGeographicSociety Sources Dunn,MargeryG.(Editor).(1989,1993)."ExploringYourWorld:TheAdventureofGeography."Washington,D.C.:NationalGeographicSociety. LastUpdated March17,2011 UserPermissions Forinformationonuserpermissions,pleasereadourTermsofService.Ifyouhavequestionsabouthowtociteanythingonourwebsiteinyourprojectorclassroompresentation,pleasecontactyourteacher.Theywillbestknowthepreferredformat.Whenyoureachouttothem,youwillneedthepagetitle,URL,andthedateyouaccessedtheresource. Media Ifamediaassetisdownloadable,adownloadbuttonappearsinthecornerofthemediaviewer.Ifnobuttonappears,youcannotdownloadorsavethemedia. Text TextonthispageisprintableandcanbeusedaccordingtoourTermsofService. Interactives Anyinteractivesonthispagecanonlybeplayedwhileyouarevisitingourwebsite.Youcannotdownloadinteractives. RelatedResources Extinction ExtinctionisthecompletedisappearanceofaspeciesfromEarth.Speciesgoextincteveryyear,buthistoricallytheaveragerateofextinctionhasbeenveryslowwithafewexceptions.Thefossilrecordrevealsfiveuniquelylargemassextinctioneventsduringwhichsignificanteventssuchasasteroidstrikesandvolcaniceruptionscausedwidespreadextinctionsoverrelativelyshortperiodsoftime.Somescientiststhinkwemighthaveenteredoursixthmassextinctioneventdrivenlargelybyhumanactivity.Ourplanetisdependentonaninterconnectedsystem.Ifweloseonespecies,howdoesthatimpactthewholesystem?Whatifwelosehundreds? Helpyourstudentsunderstandthegravityofextinctionwiththeseclassroomresources. ViewCollection NaturalSelection Thetheoryofnaturalselectionwasexploredby19th-centurynaturalistCharlesDarwin.Naturalselectionexplainshowgenetictraitsofaspeciesmaychangeovertime.Thismayleadtospeciation,theformationofadistinctnewspecies.Selectfromtheseresourcestoteachyourclassroomaboutthissubfieldofevolutionarybiology. ViewCollection Genetics Heredity,orthepassingofcharacteristicsfromonegenerationtothenext,isaconceptthathumanshaveusedforthousandsofyearsaswe’vecultivatedcropsandselectivelybredanimals.ButthefirstformalgeneticstudywasundertakenbyamonknamedGregorMendelinthemiddleofthe19thCentury.Mendelbredpeasandnoticedhecouldcross-pollinatethemincertainwaystogetgreenoryellowseeds.Today,thefieldofgeneticsisbreakingnewgroundsearchingfornewwaystotreatdiseaseordevelopcropsmoreresistanttoinsectsordrought. Empoweryourstudentstolearnaboutgeneticswiththiscollectionofresources. ViewCollection EndangeredSpeciesCategoriesandCriteria ScientistsattheInternationalUnionfortheConservationofNature(IUCN)usethesecriteriatogroupanimalpopulationsworldwide. ViewArticle SOS—SavingOurSpecies ThisactivitylaunchestheExtinctionStinks!unit.Studentswatchavideoexploringtherisingplightofendangeredspeciesaroundtheworld.TheythenusethelensofthecriticallyendangeredSumatranrhinotoidentifywhattheyneedtoknowtoanswertheunit’sdrivingquestion,“Howcanwepreventaspeciesfromgoingextinctwhilealsomeetingtheneedsofhumansandotherlocalspecies?” ViewActivity Conservation ConservationistheactofprotectingEarth’snaturalresourcesforcurrentandfuturegenerations. ViewArticle RelatedResources Extinction ExtinctionisthecompletedisappearanceofaspeciesfromEarth.Speciesgoextincteveryyear,buthistoricallytheaveragerateofextinctionhasbeenveryslowwithafewexceptions.Thefossilrecordrevealsfiveuniquelylargemassextinctioneventsduringwhichsignificanteventssuchasasteroidstrikesandvolcaniceruptionscausedwidespreadextinctionsoverrelativelyshortperiodsoftime.Somescientiststhinkwemighthaveenteredoursixthmassextinctioneventdrivenlargelybyhumanactivity.Ourplanetisdependentonaninterconnectedsystem.Ifweloseonespecies,howdoesthatimpactthewholesystem?Whatifwelosehundreds? Helpyourstudentsunderstandthegravityofextinctionwiththeseclassroomresources. ViewCollection NaturalSelection Thetheoryofnaturalselectionwasexploredby19th-centurynaturalistCharlesDarwin.Naturalselectionexplainshowgenetictraitsofaspeciesmaychangeovertime.Thismayleadtospeciation,theformationofadistinctnewspecies.Selectfromtheseresourcestoteachyourclassroomaboutthissubfieldofevolutionarybiology. ViewCollection Genetics Heredity,orthepassingofcharacteristicsfromonegenerationtothenext,isaconceptthathumanshaveusedforthousandsofyearsaswe’vecultivatedcropsandselectivelybredanimals.ButthefirstformalgeneticstudywasundertakenbyamonknamedGregorMendelinthemiddleofthe19thCentury.Mendelbredpeasandnoticedhecouldcross-pollinatethemincertainwaystogetgreenoryellowseeds.Today,thefieldofgeneticsisbreakingnewgroundsearchingfornewwaystotreatdiseaseordevelopcropsmoreresistanttoinsectsordrought. Empoweryourstudentstolearnaboutgeneticswiththiscollectionofresources. ViewCollection EndangeredSpeciesCategoriesandCriteria ScientistsattheInternationalUnionfortheConservationofNature(IUCN)usethesecriteriatogroupanimalpopulationsworldwide. ViewArticle SOS—SavingOurSpecies ThisactivitylaunchestheExtinctionStinks!unit.Studentswatchavideoexploringtherisingplightofendangeredspeciesaroundtheworld.TheythenusethelensofthecriticallyendangeredSumatranrhinotoidentifywhattheyneedtoknowtoanswertheunit’sdrivingquestion,“Howcanwepreventaspeciesfromgoingextinctwhilealsomeetingtheneedsofhumansandotherlocalspecies?” ViewActivity Conservation ConservationistheactofprotectingEarth’snaturalresourcesforcurrentandfuturegenerations. ViewArticle EducationalResourcesinYourInbox JoinourcommunityofeducatorsandreceivethelatestinformationonNationalGeographic'sresourcesforyouandyourstudents. signup EducationalResourcesinYourInbox JoinourcommunityofeducatorsandreceivethelatestinformationonNationalGeographic'sresourcesforyouandyourstudents. signup