【威学教育】王鑫托福阅读TPO27-3阅读文本

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1、【王鑫托福阅读】托福TPO全集之TPO27-3TPO27TP027-3PredatorPreyCycles1.Inparagraph1,whydoestheauthordiscussthemooseandwolvesonIsleRoyale?AToprovideanexampleofpredatorsmovingtonewhabitatsbyfollowingmigratingpreyBToshowthattheinteractionsbetweenpredatorpopulationsandprey

2、populationsarenotalwaysmightbeexpectedCTosuggestthatpreypopulationsaremoreinfluencedbypredationthanfoodavailabilityanddiseaseDToarguethatstudiesofgeographicallyisolatedpopulationstendnottobeusefultonaturalists2.Theword"rebound”inthepassageisclosestinmea

3、ningtoAescapeBrecoverCsurviveDresist3.Paragraph2implieswhichofthefollowingaboutexperimentalenvironmentsinwhichpredatorsbecomeextinct?ATheymayyieldresultsthatdonotaccuratepredictchangesofpopulationsinthewild・BIntheseenvironments,thepreyspeciesisbetterada

4、ptedthanthepredatorspecies.CTheseenvironmentsareappropriateonlyforstudyingsmallpopulationsofpredatorsandprey.DTheyareunrealisticbecausesomepredatorsarealsothepreyofotherpredators・1.Whichofthefollowingcanbeinferredfromparagraphs2and3aboutthesmal1mammalst

5、hatexperieneepopulationcycles?ATheirpopulationcyclesarenotaffectedbypredators.BTheirpredators^populationsperiodicallydisappear・CTheytypicallyundergoten-yearcycles・DTheyhaveaccesstoplacessafefrompredators-Howdopredatorsaffectpopulationsofthepreyanimals?T

6、heanswerisnotassimpleasmightbethought・MoosereachedIsleRoyaleinLakeSuperiorbycrossingoverwintericeandmultipliedfreelythereinisolationwithoutpredators・Whenwolveslaterreachedtheisland,naturalistswidelyassumedthatthewolveswouldplayakeyroleincontrollingthemo

7、osepopulation.Carefulstudieshavedemonstrated,however,thatthisisnotthecase.ThewolveseatmostlyoldordiseasedanimaIsthatwouldnotsurvivelonganyway.Ingeneral,themoosepopulationiscontrolledbyfoodavailability,diseaseandotherfactorsratherthanbywolves-Whenexperim

8、entalpopulationsaresetupundersimplelaboratoryconditions,thepredatoroftenexterminatesitspreyandthenbecomesextinctitself,havingnothinglefttoeat・However,ifsafeareaslikethosepreyanimalshaveinthewiIdareprovided,thepreypopulationdropst