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为了帮助大家高效备考托福,为大家带来托福TPO29阅读Passage2原文文本+题目+答案 解析,希望对大家备考有所帮助。 Competition Whenseveralindividualsofthesamespeciesorofseveraldifferentspecies dependonthesamelimitedresource,asituationmayarisethatisreferredtoas competition.Theexistenceofcompetitionhasbeenlongknowntonaturalists;its effectsweredescribedbyDarwininconsiderabledetail.Competitionamong individualsofthesamespecies(intraspeciescompetition),oneofthemajor mechanismsofnaturalselection,istheconcernofevolutionarybiology.Competition amongtheindividualsofdifferentspecies(interspeciescompetition)isamajor concernofecology.Itisoneofthefactorscontrollingthesizeofcompeting populations,andextremecasesitmayleadtotheextinctionofoneofthecompeting species.ThiswasdescribedbyDarwinforindigenousNewZealandspeciesofanimals andplants,whichdiedoutwhencompetingspeciesfromEuropewereintroduced. 当同一物种的不同个体或不同的物种都依靠同一有限资源时,这种情况往往会引发成所 谓的竞争。竞争的存在已为生物学家们所熟知,其结果也已被达尔文详尽叙述过。同一物种 不同个体之间的竞争(种内竞争),作为自然选择的一个主要原理,现在属于进化生物学。不 同物种个体之间的竞争(种间竞争)是生态学的主要部分。它是控制有竞争关系的种群数量的 一个因素,而其极端情况可能导致竞争的一方灭绝。达尔文在描述新西兰本土动植物物种在 与引进的欧洲物种的竞争中灭绝时讲到该情况。 Noseriouscompetitionexistswhenthemajorneededresourceisinsuperabundant supply,asinmostcasesofthecoexistenceofherbivores(plant eaters).Furthermore,mostspeciesdonotdependentirelyonasingleresource,ifthe majorresourceforaspeciesbecomesscarce,thespeciescanusuallyshiftto alternativeresources.Ifmorethanonespeciesiscompetingforascarceresource,the competingspeciesusuallyswitchtodifferentalternativeresources.Competitionis usuallymostsevereamongcloserelativeswithsimilardemandsontheenvironment.But itmayalsooccuramongtotallyunrelatedformsthatcompeteforthesame resource,suchasseed-eatingrodentsandants.Theeffectsofsuchcompetitionare graphicallydemonstratedwhenalltheanimalsoralltheplantsinanecosystemcome intocompetition,ashappened2millionyearsagoattheendofPliocene,whenNorth andSouthAmericabecamejoinedbytheIsthmusofPanama.NorthandSouthAmerican speciesmigratingacrosstheIsthmusnowcameintocompetitionwitheachother.The resultwastheextermination