首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Birds that are literally half-asleep—with one brain hemisphere alert and the other sleeping—control which side of the brain rema
Birds that are literally half-asleep—with one brain hemisphere alert and the other sleeping—control which side of the brain rema
admin
2019-06-23
61
问题
Birds that are literally half-asleep—with one brain hemisphere alert and the other sleeping—control which side of the brain remains awake, according to a new study of sleeping ducks.
Earlier studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemisphere’s eye stays open and alert. Birds also can sleep with both hemispheres resting at once.
Decades of studies of bird flocks led researchers to predict extra alertness in the more vulnerable, end-of-the-row sleepers. Sure enough, the end birds tended to watch carefully on the side away from their companions. Ducks in the inner spots showed no preference for gaze direction.
Also, birds doping(打盹)at the end of the line resorted to single-hemisphere sleep, rather than total relaxation, more often than inner ducks did. Rotating 16 birds through the positions in a four-duck row, the researchers found outer birds half-asleep during some 32 percent of dozing time versus about 12 percent for birds in internal spots.
"We believe this is the first evidence for an animal behaviorally controlling sleep and wakefulness simultaneously in different regions of the brain," the researchers say.
The results provide the best evidence for a long-standing supposition that single-hemisphere sleep evolved as creatures scanned for enemies. The preference for opening an eye on the lookout side could be widespread, he predicts. He’s seen it in a pair of birds dozing side-by-side in the zoo and in a single pet bird sleeping by a mirror. The mirror-side eye closed as if the reflection were a companion and the other eye stayed open.
Useful as half-sleeping might be, it’s only been found in birds and such water mammals(哺乳动物)as dolphins, whales, and seals. Perhaps keeping one side of the brain awake allows a sleeping animal to surface occasionally to avoid drowning.
Studies of birds may offer unique insights into sleep. Jerome M. Siegel of the UCLA says he wonders if birds’ half-brain sleep "is just the tip of the iceberg(冰山)." He speculates that more examples may turn up when we take a closer look at other species.
The example of a bird sleeping in front of a mirror indicates that _____.
选项
A、the phenomenon of birds dozing in pairs is widespread
B、birds prefer to sleep in pairs for the sake of security
C、even an imagined companion gives the bird a sense of security
D、a single pet bird enjoys seeing its own reflection in the mirror
答案
C
解析
第6段最后两句提到“研究者看见一只鸟儿靠着镜子睡觉。那只鸟对着镜子的那只眼睛是闭着的,仿佛镜中的影像是它的同伴,而它的另外一只眼则是睁开的”,C与此一致。A和B中的in pairs是对原文的误读:鸟儿喜欢结群(而不一定是成双成对)睡眠,文章前几段对此有说明。D中的enjoy属于无中生有。
转载请注明原文地址:https://kaotiyun.com/show/N3X7777K
0
大学英语六级
相关试题推荐
A、Theycan’ttalksotheycan’tproduceanyspeech.B、Theycanonlyproducethesoundof"R"atfirst.C、Theycan’tdiscriminate
VideogameshavebecomeincreasinglypopularinbotharcadesandtheaverageAmericanhome.Peopleofallagesandfromallwalk
EatingOurYoung[A]AtFeltonvilleSchoolofArtsandSciences,amiddleschoolinapoorneighborhoodofPhiladelphia,thesch
EatingOurYoung[A]AtFeltonvilleSchoolofArtsandSciences,amiddleschoolinapoorneighborhoodofPhiladelphia,thesch
KyleMaguirewantedtoattendtheUniversityofNebraskaassoonashegraduatedfromhighschoolyearsago.AnaspiringWebdev
Afterdecadesofdecline,theshareofmotherswhostayhomewiththeirchildrenhas【C1】______risenoverthelastseveralyears
Everyotherweekitseemsanewstudycomesoutthataddstoouralready-formidablestoreofparentalworries.Butevenbythose
TheFutureIsAnotherCountry[A]AcoupleofmonthsorsoafterbecomingBritain’sprimeminister,DavidCameronwantedafewt
A、Thepopulationwillincreaseuncontrollably.B、Peoplewillsufferfrommoreseriouslackoffood.C、800millionpeoplewilldi
随机试题
按分段责任制规定,多式联运经营人的责任范围以各区段运输原有责任危险认定,如海上区段办理依据是()
女性,52岁,因结节性甲状腺肿接受了甲状腺大部切除术。术中顺利,术后安返病房。护士指导该病人在术后当天进温凉流食的目的是()
A.伊贝母B.麻黄C.杜仲D.牡丹皮E.甘松在新疆维吾尔聚居区维医常用的维药是
C声级由国际标准化组织(ISO)推荐,用作噪声卫生评价的指标。()
房地产投资项目财务评价主要采用盈亏平衡分析法、敏感性分析法和概率分析法等。()
某商业中心地上4层、地下1层,建筑高度20m,耐火等级一级,每层层高均为5m,每层建筑面积均为10000m2,按有关国家工程建设消防技术标准配置了自动喷水灭火系统、火灾自动报警系统等消防设施及器材。某歌舞厅位于该商业中心的地下一层至地上四层,每层歌舞厅的建
货运企业定价的主要方法有()。
编制银行存款余额调节表时,下列未达账项中,会导致企业银行存款日记账的账面余额小于银行对账单余额的有()。
班级组织
设X~b(25,p1),Y~b(25—X,p2),求:EY,DY.
最新回复
(
0
)