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
2016-04-30
69
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.
While sleeping, some water mammals tend to keep half awake in order to_____.
选项
A、alert themselves to the approaching enemy
B、emerge from water now and then to breathe
C、be sensitive to the ever-changing environment
D、avoid being swept away by rapid currents
答案
B
解析
第7段末句提到“也许一边大脑保持清醒是为了让睡眠中的动物不时浮出水面以免被淹死”,B与文中所提及的观点一致。
转载请注明原文地址:https://kaotiyun.com/show/DxG7777K
0
大学英语六级
相关试题推荐
Birdsthatareliterallyhalfasleep—withonebrainhemispherealertandtheothersleeping—controlwhichsideofthebrain
A、Rainusuallycomeswithoutthunderandlightning.B、ItisusuallydryinApril.C、Childrenpaynoattentiontonaturalphenome
A、Theyarelookingforanapartmenttolivein.B、Theyarediscussinglivingplacesandchildren’seducation.C、Theyarecomplai
万里长城是中华民族的象征,中国人的骄傲。长城全长6350多千米,是世界上规模最大的军事防御工程(militarydefenseproject),被列为世界七大建筑奇迹(thesevenancientarchitecturalwonders)之一
A、Piracyisaneasythingtocommit.B、Inventionusuallyneedsheavycost.C、Patentisusefulbutnotpractical.D、Inventionsar
Cosmeticorplasticsurgeryoftenevokesimagesoffamouspersonalitieswantingtoaltertheirappearancesthrough【B1】______surg
Whatifclothingwasmorethanjustanaccessory?Thegreenmovementisnotnewtofashion,andmanydesignersandmanufacturers
Whatifclothingwasmorethanjustanaccessory?Thegreenmovementisnotnewtofashion,andmanydesignersandmanufacturers
Ahundredyearsago,itwasassumedandscientifically"proved"byeconomiststhatthelawsofsocietymadeitnecessarytohave
Architectsanddesignershaveutilized3Dprintingtechnologyaspartoftheirworkformanyyears,butitisonlynowthatana
随机试题
简述律师事务所被取消会员资格的情形。
在改革开放具体政策措施上之所以不能陷入姓“资”还是姓“社”的抽象争论,是因为()。
以( )为标的合同,其数量主要表现为智力成果的价值。
下列不属于制定执业质量制度应遵循原则的是()。
某煤矿企业为了赶进度,违反安全生产程序进行超量挖掘,这种行为不符合安全生产的()要求。
国务院证券监督管理机构依照法定条件负责核准股票发行申请,下列有关核准程序的说法正确的是()。
班主任崔老师想要了解本班学生所有学科的学习情况,负责安排此项工作的学校职能部门是()。
设f(x)在[0,π]上连续,在(0,π)内可导,证明:至少存在一点ξ∈(0,π),使得f’(ξ)=一f(ξ)cotξ.
Thehours______thechildrenspendintheirone-wayrelationshipwithtelevisionpeople,undoubtedlyaffecttheirrelationships
WhenwasMargaretThatcherborn?MargaretThatcherwasborn__________.
最新回复
(
0
)