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
专升本
Birds that are literally half asleep—with one brain hemisphere alert and the other sleeping— control which side of the brain rem
Birds that are literally half asleep—with one brain hemisphere alert and the other sleeping— control which side of the brain rem
admin
2016-03-05
25
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 companies. Ducks in the inner spots showed no preference for gaze direction.
Also, birds dozing 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 was accompanied, and the other eye stayed open.
Useful as half sleeping might be, it’s only been found in birds and such water mammals 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
". He speculates that more examples may turn up when we take a closer look at other species.
According to the passage, birds often half sleep because______.
选项
A、they have to watch out for possible attacks
B、their brain hemispheres take turns to rest
C、the two halves of their brain are differently structured
D、they have to constantly keep an eye on their companions
答案
A
解析
根据第五段The results provide the best evidence for a long—standing supposition thatsingle hemisphere sleep evolved as creatures scanned for enemies.可知研究表明这种睡眠时保持半个大脑清醒的进化结果是为了防御天敌,故A正确。
转载请注明原文地址:https://kaotiyun.com/show/1UHC777K
本试题收录于:
英语题库普高专升本分类
0
英语
普高专升本
相关试题推荐
Alanguageisasignalingsystemwhichoperateswithsymbolicvocalsounds(语声),andwhichisusedbyagroupofpeopleforthep
Alanguageisasignalingsystemwhichoperateswithsymbolicvocalsounds(语声),andwhichisusedbyagroupofpeopleforthep
Stillnotsurewhyyoushouldbelearningaforeignlanguage?Herearesomeverygood【B1】______.First,aforeignlanguagemake
Stillnotsurewhyyoushouldbelearningaforeignlanguage?Herearesomeverygood【B1】______.First,aforeignlanguagemake
Ifyou_____5minutesearlier,you_____him.
AfterlivinginPairsforfiftyyearshereturnedtothesmalltown____hegrewupasachild.
Newspapersarenotnearlyaspopulartodayastheywereinthepast.Therearenotverymanypeoplewhoseriouslyreadanewspap
Incitieswithrentcontrol,thecitygovernmentsetsthemaximumrentthatalandlordcanchargeforanapartment.Supporterso
Technologyistheapplicationofknowledgetoproduction.Thankstomoderntechnology,wehavebeenabletoincreasegreatlythe
Technologyistheapplicationofknowledgetoproduction.Thankstomoderntechnology,wehavebeenabletoincreasegreatlythe
随机试题
洋地黄治疗房颤,减慢心室率的最主要作用是
调整有配血禁忌的处方,必须经
题2~6:某底层为钢筋混凝土框架一抗震墙的五层砌体房屋,抗震设防烈度为7度,设计基本地震加速度为0.1g。假定各层质点集中在楼层标高处,其各层重力荷载代表值及各层层高如图3-12。底层横向所有框架柱的横向侧向刚度为9.0×105kN/m,底层横向所有钢筋混
属于第二类压力容器的是()。
某教师在一次阶段测验中,设计了如下试题考查学生。将标准状况下336LHCl气体溶解在1L水中,得到密度为1.17g/cm3的盐酸,求此盐酸的物质的量浓度。其中有42.6%的学生按下述思路解题。【解题过程】试根据上述解题过程回答下列问题:(1)该题
学生努力学习是为了改变自己在班级中的排名,此成就动机属于()
9岁的田田是一个很聪明的孩子,语言表达能力比较突出,思维清晰,反应敏捷。在学校里有时与同学有小纠纷,他总说是别人的错而不反思自己的问题。他平时喜欢做手工和小种植,在学习上却不愿意花精力投入。家长对孩子的管理是粗放和随意的,管得紧一点时,孩子的表现就好一些,
下列有关饮食的说法错误的是()。
专家与知识分子这两个概念并不重合。术业有专攻,固然是重要的,但未必就能从中形成一个知识分子的精神气质、天下关怀的人生态度和敢于怀疑、敢为天下先的批判精神。如果大学只能培养出与社会的多元职业结构相一致的各类专家,那么,我们民族的精神存在将不再可能在一个特定的
把数学表达式表示为正确的VB表达式应该是( )。
最新回复
(
0
)