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
38
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
A、Studyinghistory.B、Buyinglotterytickets.C、Registeringforcourses.D、Goingtoanartgallery.C对话中女士说电子工程学(thedoubleEele
Historically,humansgetseriousaboutavoidingdisastersonlyafteronehasjuststruckthem.Bythatlogic,2006shouldhaveb
Historically,humansgetseriousaboutavoidingdisastersonlyafteronehasjuststruckthem.Bythatlogic,2006shouldhaveb
WhenIwasachild,myteethusedto【B1】______inseveraldifferentdirections,and【B2】______thatinvolvedratherexpensive【B3】__
WhenIwasachild,myteethusedto【B1】______inseveraldifferentdirections,and【B2】______thatinvolvedratherexpensive【B3】__
A、Themeaningoffacialexpressionsdependsonsituations.B、Facialexpressionscancausemisunderstandingacrossculture.C、Peo
Cosmeticorplasticsurgeryoftenevokesimagesoffamouspersonalitieswantingtoaltertheirappearancesthrough【B1】______surg
Cosmeticorplasticsurgeryoftenevokesimagesoffamouspersonalitieswantingtoaltertheirappearancesthrough【B1】______surg
A、Themanshouldbuyavacuumcleaner.B、Theman’sparentsareeagertoseetheirson.C、Theman’sparentsshouldcomeatanothe
随机试题
某有限责任公司的自然人股东甲死亡,公司章程对于股权继承无特别规定。根据公司法律制度的规定,甲的合法继承人享有的权利是()。
Pickouttheappropriateexpressionsfromtheeightchoicesbelowandcompletethefollowingdialoguebyblackeningthecorrespo
何谓输卵管癌“三联征”?
下列关于肝肾综合症的叙述正确的是()
A、堇菜科,含苷类和黄酮类成分B、报春花科,水浸后,对光可见黑色或褐色条纹C、菊科,含抗疟有效成分D、唇形科,含有橙皮苷结晶E、爵床科,含钟乳体青蒿的来源及特征为
背景资料:某施工单位承包了东风水库工程施工,制定的施工方案中部分内容如下:(1)水库大坝施工采用全段围堰法导流。相关工作内容有:①截流;②围堰填筑;③围堰拆除;④导流隧洞开挖;⑤下闸蓄
企业自行建造固定资产过程中发生的下列事项,应计入营业外支出的有()。
1998年诺贝尔经济学奖得主阿马蒂亚.森在《伦理学与经济学》一书中,对经济学与伦理学的关系问题进行了可贵的探索。他认为,从亚里士多德开始,经济学本来就具有两种根源,即两种人类行为的目的:一种是对财富的关注,一种是更深层次上的目标追求。由此产生两种方法,一种
社会治理是社会建设的重大任务,是国家治理的重要内容。我国现阶段要构建的社会治理体制的特点有()
今天的电影别提多没劲了,我看着看着都睡着了。
最新回复
(
0
)