资源描述：
《新gre阅读机经：鸟叫研究》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
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
