首页
登录
职称英语
Birds that are literally half-asleep—with one brain hemisphere alert and the
Birds that are literally half-asleep—with one brain hemisphere alert and the
游客
2024-04-09
46
管理
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. [br] 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:http://tihaiku.com/zcyy/3547953.html
相关试题推荐
Birdsthatareliterallyhalf-asleep—withonebrainhemispherealertandthe
Birdsthatareliterallyhalf-asleep—withonebrainhemispherealertandthe
[originaltext]Amobileofficeis,quiteliterally,anofficewhichiscapab
[originaltext]Amobileofficeis,quiteliterally,anofficewhichiscapab
[originaltext]Amobileofficeis,quiteliterally,anofficewhichiscapab
Birdsthatareliterallyhalf-asleep—withonebrainhemispherealertandthe
Birdsthatareliterallyhalf-asleep—withonebrainhemispherealertandthe
Birdsthatareliterallyhalf-asleep—withonebrainhemispherealertandthe
Birdsthatareliterallyhalf-asleep—withonebrainhemispherealertandthe
Birdsthatareliterallyhalf-asleep—withonebrainhemispherealertandthe
随机试题
Whendiditbegintorain?[br][originaltext]W:John,wasitrainingwhenyou
Thenew(nation)______museumwillbeopentothepublicnextweek.national本题考查词
[originaltext]W:Hey,Mark,couldyoutellmeaboutthefirstjobyoueverhad?
[originaltext]M:Doyougoouttowork?W:Notregularly.Iworkathomemosto
对建设项目方案设计招标投标活动实施监督管理的部门为( )。A.乡镇级以上地方人
教育者按照一定社会或阶级的要求,有目的、有计划、系统地对受教育者施加思想、政治和
A.脂肪管型 B.蜡样管型 C.透明管型 D.颗粒管型 E.白细胞管型肾
《新型玻璃》 《新型玻璃》 夜深了,从一座陈列珍贵字画的博物馆里,突然传出了
梅毒螺旋体感染的抗体检测试验中,下列哪项检测的是非特异性抗体?( )A.FTA
当采购部门在节约成本上处于领先地位时,较倾向于使用的采购成本控制方法是()。A
最新回复
(
0
)