首页
登录
职称英语
Over the years, biologists have suggested two main pathways by which sexual
Over the years, biologists have suggested two main pathways by which sexual
游客
2023-12-11
52
管理
问题
Over the years, biologists have suggested two main pathways by which sexual selection natural selection for characters that confer success in competition for a mate as distinguished from competition with other species; also: the choice of a mate based on a preference for certain characteristics may have shaped the evolution of male birdsong. In the first place, male competition and intrasexual selection produce relatively short, simple songs used mainly in territorial behavior. In the second place, female choice and intersexual selection produce longer, more complicated songs used mainly in mate attraction; like such visual ornamentation as the peacock’s tail, elaborate vocal characteristics increase the male’s chances of being chosen as a mate, and he thus enjoys more reproductive success than his less ostentatious rivals. The two pathways are not mutually exclusive, and we can expect to find examples that reflect their interaction. Teasing for microscopic examination them apart has been an important challenge to evolutionary biologists.
Early research confirmed the role of intrasexual selection. In a variety of experiments in the field, males responded aggressively to recorded songs by exhibiting territorial behavior near the speakers. The breakthrough for research into intersexual selection came in the development of a new technique for investigating female response in the laboratory. When female cowbirds raised in isolation in sound-proof chambers were exposed to recordings of male song, they responded by exhibiting mating behavior. By quantifying the responses, researchers were able to determine what particular features of the song were most important. In further experiments on song sparrows, researchers found that when exposed to a single song type repeated several times or to a repertoire of different song types, females responded more to the latter. The beauty of the experimental design is that it effectively rules out confounding variables; acoustic isolation assures that the female can respond only to the song structure itself.
If intersexual selection operates as theorized, males with more complicated songs should not only attract females more readily but should also enjoy greater reproductive success. At first, however, researchers doing fieldwork with song sparrows found no correlation between larger repertoires and early mating, which has been shown to be one indicator of reproductive success; further, common measures of male quality used to predict reproductive success, such as weight, size, age, and territory, also failed to correlate with song complexity.
The confirmation researchers had been seeking was finally achieved in studies involving two varieties of warblers. Unlike the song sparrow, which repeats one of its several song types in bouts before switching to another, the warbler continuously composes much longer and more variable songs without repetition. For the first time, researchers found a significant correlation between repertoire size and early mating, and they discovered further that repertoire size had a more significant effect than any other measure of male quality on the number of young produced. The evidence suggests that warblers use their extremely elaborate songs primarily to attract females, clearly confirming the effect of intersexual selection on the evolution of birdsong. [br] The passage is primarily concerned with______.
选项
A、showing that intrasexual selection has a greater effect on birdsong than does intersexual selection
B、contrasting the role of song complexity in several species of birds
C、describing research confirming the suspected relationship between intersexual selection and the complexity of birdsong
D、demonstrating the superiority of laboratory work over field studies in evolutionary biology
答案
C
解析
主旨题。根据全文判断,主要是研究intersexual selection和the complexityof birdsong之间关系的,所以选C项。
转载请注明原文地址:https://tihaiku.com/zcyy/3263582.html
相关试题推荐
Allovertheworld,moreboysarebornthangirls.Evolutionarybiologistsb
Allovertheworld,moreboysarebornthangirls.Evolutionarybiologistsb
TheU.S.CentersforDiseaseControlsuggestedroutineHIVtestsfor[br][ori
TheU.S.CentersforDiseaseControlsuggestedroutineHIVtestsfor[originalt
Why"time-out"isNOTsuggestedasameanstostopchildrenfromdoingsomething
Why"time-out"isNOTsuggestedasameanstostopchildrenfromdoingsomething
Why"time-out"isNOTsuggestedasameanstostopchildrenfromdoingsomething
Itissuggestedthatuniversitiesshouldrequireeverystudenttotakeavar
Overtheyears,biologistshavesuggestedtwomainpathwaysbywhichsexual
______hadanevidentinfluenceonnaturalism,whichsuggestedmanwasdominated
随机试题
PartⅡReadingComprehension(SkimmingandScanning)Directions:Inthispart,y
围挡的高度:市区主要路段不宜低于2.2m;一般路段不低于1.5m。
下列各项,关于中央型肺癌叙述,错误的是A、发生在段支气管至主支气管 B、发生在
关于基金信息披露的说法,不正确的是( )。A.有利于提高基金的投资业绩 B.
患者主诉骨痛,血浆蛋白质电泳图谱的变化为ALB减少,β-γ区带出现典型M蛋白,此
执行慢性胃炎患者的医嘱时,使用前应着重与医生进行沟通的药物是A.消胆胺 B.山
在带电的电流互感器二次回路上工作时,以下做法正确的是()。A.禁止将电流
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定规律性: A.如上
小刚生活在一个充满家庭暴力的家庭,父亲经常殴打他和母亲,为此,小刚向社区工作者求
一个人在解决问题时能触类旁通,说明这个人的思维具有()。 A.流畅性B.变通
最新回复
(
0
)