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1、新GRE阅读机经:鸟叫研究 下面是小编为大家整理的新GRE机经的阅读部分,这篇是关于“鸟叫研究”的新GRE阅读机经,希望可以帮助各位考生打开阅读思路,提高新GRE阅读能力。 鸟叫研究 Overtheyears,biologistshavesuggestedtwomainpathwaysbywhichsexualselectionmayhaveshapedtheevolutionofmalebirdsong.Inthefirst,malecompetitionandintrasexualselectionproduce
2、relativelyshort,simplesongsusedmainlyinterritorialbehavior.Inthesecond,femalechoiceandintersexualselectionproducelonger,morecomplicatedsongsusedmainlyinmateattraction;likesuchvisualornamentationasthepeacock’stail,elaboratevocalcharacteristicsincreasethemale’schance
3、sofbeingchosenasamate,andhethusenjoysmorereproductivesuccessthanhislessostentatiousrivals.Thetwopathwaysarenotmutuallyexclusive,andwecanexpecttofindexamplesthatreflecttheirinteraction.Teasingthemaparthasbeenanimportantchallengetoevolutionarybiologists. Earlyresear
4、chconfirmedtheroleofintrasexualselection.Inavarietyofexperimentsinthefield,malesrespondedaggressivelytorecordedsongsbyexhibitingterritorialbehaviornearthespeakers.Thebreakthroughforresearchintointersexualselectioncameinthedevelopmentofanewtechniqueforinvestigatingf
5、emaleresponseinthelaboratory.Whenfemalecowbirdsraisedinisolationinsound-proofchamberswereexposedtorecordingsofmalesong,theyrespondedbyexhibitingmatingbehavior.Byquantifyingtheresponses,researcherswereabletodeterminewhatparticularfeaturesofthesongweremostimportant.I
6、nfurtherexperimentsonsongsparrows,researchersfoundthatwhenexposedtoasingle24songtyperepeatedseveraltimesortoarepertoireofdifferentsongtypes,femalesrespondedmoretothelatter.Thebeautyoftheexperimentaldesignisthatiteffectivelyrulesoutconfoundingvariables;acousticisola
7、tionassuresthatthefemalecanrespondonlytothesongstructureitself. Ifintersexualselectionoperatesastheorized,maleswithmorecomplicatedsongsshouldnotonlyattractfemalesmorereadilybutshouldalsoenjoygreaterreproductivesuccess.Atfirst,however,researchersdoingfieldworkwiths
8、ongsparrowsfoundnocorrelationbetweenlargerrepertoiresandearlymating,whichhasbeenshowntobeoneindicatorofreproductivesuccess;further,commonmeasures