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1、bailiedu.comTPO36Passage1阅读文章和题目为了方便大家学习，这是小编为大家从模考软件里整理出来的TPO36Passage1的阅读文章和题目，这是最新的TPO了，大家还在等什么？Habitatsandchipmunkspecies♦ThereareeightchipmunkspeciesintheSierraNevadamountainrange,andmostofthemlookprettymuchalike.Buteightdifferentspeciesofchipmunksscurryin
2、garoundapicnicareawillnotbefound.NowhereintheSierradoalleightspeciesoccurtogether.Eachspeciestendsstronglytooccupyaspecifichabitattype,withinanelevationalrange,andtheoverlapamongthemisminimal.♦TheeightchipmunkspeciesoftheSierraNevadarepresentbutafewofthe15speci
3、esfoundinwesternNorthAmerica,yetthewholeofeasternNorthAmericamakesdowithbutonespecies:theEasternchipmunk.WhyaretheresomanyverysimilarchipmunksintheWest?ThepresenceoftallmountainsinterspersedwithvastareasofariddesertandgrasslandmakestheWestecologicallyfardiffere
4、ntfromtheEast.TheWestaffordsmuchmoreopportunityforchipmunkpopulationstobecomegeographicallyisolatedfromoneanother,aconditionofspeciesformation.Also,therearemoreextremesinwesternhabitats.IntheSierraNevada,highelevationsareclosetolowelevations,atleastintermsofmil
5、eage,butecologicallytheyareverydifferent.♦Mostecologistsbelievethatancientpopulationsofchipmunksdivergedgeneticallywhenisolatedfromoneanotherbymountainsandunfavorableecologicalhabitat.These地址：北京市海淀区海淀北二街8号中关村SOHOA区2层电话：400-890-6000传真：010-82607462网址：bailiedu.com
6、邮编:100080bailiedu.comscatteredpopulationsfirstevolvedintoraces—adaptedtothelocalecologicalconditions—andthenintospecies,reproductivelyisolatedfromoneanother.Thisperiodofevolutionwasrelativelyrecent,asevidencedbythesimilarappearanceofallthewesternchipmunkspecies
7、.EcologistshavestudiedthefourchipmunkspeciesthatoccurontheeasternslopeoftheSierraandhavelearnedjusthowthesespeciesinteractwhileremainingseparate,eachoccupyingitsownelevationalzone.Thesagebrushchipmunkisfoundatthelowestelevation,amongthesagebrush.Theyellowpinech
8、ipmunkiscommoninlowtomid-elevationsandopenconiferforests,includingpinonandponderosaandJeffreypineforests.Thelodgepolechipmunkisfoundathigherelevations,amongthelodgepoles,fir
