Birds that are half-asleep—with one brain hemisphere (半球) 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 groups led researchers to predict extra alertness in the end-of-the-row sleepers which tend to be attacked more easily. 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 napping at the end of the line depend on single-hemisphere sleep, rather than total relaxation, more often than inner ducks did. Turning 16 birds through the positions in a four-duck row, the researchers found that compared with 12 percent for birds in internal spots, outer birds half-asleep during some 32 percent of napping time.

    “We believe this is the first evidence for an animal behaviorally controlling sleep and wakefulness at the same time in different regions of the brain,” the researchers say.

    The results provide the best evidence for a long-standing assumption 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 napping 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 animals 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 supposes that more examples may turn up when we take a closer look at other species.

According to the passage, birds often half sleep because ______.

       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

What is implied about the example of a bird’s sleeping in front of a mirror?

       A. An imagined companion gives the bird a sense of security.

       B. Birds prefer to sleep in pairs for the sake of their security.

       C. The phenomenon of birds napping in pairs is widespread.

D. A single pet bird enjoys seeing its own reflection in the mirror.

While sleeping, some water animals tend to keep half awake in order to ______.

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

By saying “just the tip of the iceberg”, Siegel suggests that ______.

       A. half-brain sleep has something to do with icy weather

       B. the mystery of half-brain sleep is close to being solved

       C. most birds living in cold regions tend to be half sleepers

       D. half-brain sleep may exist among other species

【小題1】A

【小題2】A

【小題3】B

【小題4】D


解析:

練習(xí)冊系列答案
相關(guān)習(xí)題

科目:高中英語 來源: 題型:閱讀理解

Birds that are half-asleep—with one brain hemisphere (半球) 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 groups led researchers to predict extra alertness in the end-of-the-row sleepers which tend to be attacked more easily. 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 napping at the end of the line depend on single-hemisphere sleep, rather than total relaxation, more often than inner ducks did. Turning 16 birds through the positions in a four-duck row, the researchers found that compared with 12 percent for birds in internal spots, outer birds half-asleep during some 32 percent of napping time.

    “We believe this is the first evidence for an animal behaviorally controlling sleep and wakefulness at the same time in different regions of the brain,” the researchers say.

    The results provide the best evidence for a long-standing assumption 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 napping 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 animals 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 supposes that more examples may turn up when we take a closer look at other species.

According to the passage, birds often half sleep because ______.

       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

What is implied about the example of a bird’s sleeping in front of a mirror?

       A. An imagined companion gives the bird a sense of security.

       B. Birds prefer to sleep in pairs for the sake of their security.

       C. The phenomenon of birds napping in pairs is widespread.

D. A single pet bird enjoys seeing its own reflection in the mirror.

While sleeping, some water animals tend to keep half awake in order to ______.

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

By saying “just the tip of the iceberg”, Siegel suggests that ______.

       A. half-brain sleep has something to do with icy weather

       B. the mystery of half-brain sleep is close to being solved

       C. most birds living in cold regions tend to be half sleepers

       D. half-brain sleep may exist among other species

查看答案和解析>>

科目:高中英語 來源:牛津版2010年高一英語同步輔導(dǎo)練習(xí)資料 題型:閱讀理解


D  
Every August on the island of Heimaey, young people often take a walk along the street throughout the night. Why their parents allow them to stay out ? The children of Heimaey are going to save young puffins ---- small black-and-white seabirds.
The cliffs(懸崖)above the town are home to a large group of puffins . The birds dig holes all around the cliffs . These holes are their homes. The young stay in the holes for about seven weeks. Then they begin to leave . Some move slowly on their undeveloped wings and feet down to the sea around Heimaey. There they swim, which they can do naturally , and learn to dive for fish . Others, however, may lose their way at night and find themselves in the town instead. On the ground, the young birds are in trouble. Because their wings are fully developed, they cannot take off quickly to sea and safety. The birds then become a good meal for cats and other animals .
For many years, islanders have help the young puffins. At night in late August, children carrying thick paper boxes and lights hurry out to catch puffins . They spend most of the night running after the birds. They put the birds they've caught into boxes and take good care of them .
The next morning the children take the puffins to the sea and set them free. The bird will live at sea until they are at least two years old. Then they will return to the cliffs to build homes of their own.
The children of Heimaey look forward to August !
16.Every August the children of Heimaey are allowed to stay out all night.    
A.to catch puffins and take them home  B.to save puffins from danger
C.to drive puffins away  D.to run after puffins for pleasure
17.The young puffins that lose their way are in the danger of ______.
A.being killed by hunters  B.knowing nothing about the sea
C.being eaten by animals  D.having no fish to eat
18.The children put the seabirds into boxes and ______.     
A.look after them carefully for several days, then set them free
B.set them free when they grow bigger and can take off to sea and safety
C.carry them to the sea right away to set them free
D.they don' t set them free until the next morning
19.The children look forward to August because ______.     
A.they enjoy playing the game of running after seabirds
B.it' s time for them to go out at night to save puffins
C.it' s time for them to catch seabirds
D.they like to stay out at night to catch puffins
20.According to the passage, which of the following is NOT TRUE?   
A.Once a year the children are allowed to stay out at night to have a good time .
B.The earlier home for the young puffins is in the cliffs, not in the sand of shores .
C.Young puffins make their way down to the sea when they are about seven weeks old.
D.The young birds that get to the sea will stay there for at least two years before they return to the cliffs .

查看答案和解析>>

科目:高中英語 來源:2012-2013學(xué)年江蘇漣水中學(xué)高三第一次質(zhì)量檢測英語卷(解析版) 題型:閱讀理解

Blackbird (畫眉)

★A good sign

★Paradise

★Magic

Seeing a blackbird for most is a good sign. It can also mean shyness and insecurity, which directly means a lack of self-confidence. The color black, as we know, is connected with supernatural power.

Bluebird (藍(lán)知更鳥)

★The arrival of spring

★Hard work

★Joy

Bluebirds are connected with joy, and they most often mean a happy condition or good news coming your way. They may also refer to the hope of an individual for their inner child, which means innocence (單純).

Bluejay (冠藍(lán)鴉)

★Fearless

★Truthful

★Talkative

A bluejay can mean being faithful to others. Seeing a bluejay either in its natural habitat or in your dreams could also send across a message to develop an innate (先天的) talent.

Canary(金絲雀)

★Joy

★Freedom

★Intellectual development

Canaries are happy birds that spread joy and a sense of well-being. For some, a flying canary can be a sign of the spread of unwanted information. It can also mean that you are the cause of the gossip (閑話) as an individual. A canary is also a symbol of selflessness.

1.Both the bluebird and the canary can be a sign of      .

A.innocence         B.joy               C.the coming of spring D.shyness

2.Which bird can be a sign that someone is not confident?

A.The blackbird.      B.The bluebird.       C.The bluejay.        D.The canary.

3.What does it mean when you see a bluejay in your dream?

A.It means you spread unwanted information.

B.It means you man develop an innate talent.

C.It means you will have joy.

D.It means someone is missing you.

4.Which bird can mean selfessness?

A.The blackbird.      B.The bluebird.       C.The bluejay.        D.The canary.

 

查看答案和解析>>

科目:高中英語 來源:2015屆吉林省高一上學(xué)期期中考試英語試卷(解析版) 題型:閱讀理解

If you’d like to go sightseeing, the following World Heritage Sites may be your best choices.

Jiuzhaigou Valley Scenic and Historic Interest Area

The Jiuzhaigou Valley, which lies in the northern part of Sichuan Province, reaches a height of more than 4,800 meters, with a series of different forest ecosystems(生態(tài)系統(tǒng)). There you can enjoy watching excellent waterfalls. Some 140 kinds of birds also live in the valley, as well as a number of endangered plants and animals, including the giant panda. For more information, please visit http://whc.unesco.org/en/list/637.

Khami Ruins National Monument

The city of Khami, which developed after the capital of Great Zimbabwe had been given up in the mid-16th century, is of great archaeological(考古的)interest. The discovery of objects from Europe and China shows that Khami was a major centre for trade over a long period of time. For more information, please visit http://whc.unesco.org/en/list/365.

Henderson Island

Henderson Island, which lies in the eastern South Pacific, is one of the few atolls(環(huán)礁)in the world whose ecology(生態(tài))has not been touched by human beings. It is especially famous for the ten plants and four land birds that can only be seen on the island. For more information, please visit http://whc.unesco.org/en/list/487.

The Old City of Jerusalem

As a holy city for three different religions in the Middle East, Jerusalem has always been of great religious importance. It was given a World Heritage Status in 1981 and placed on the “List of World Heritage in Danger” the following year. For more information, please visit http://whc.unesco.org/en/list/148.

1.What can we know about the Jiuzhaigou Valley?

A.It sits at the foot of a 4,800-meter-high mountain.

B.It has different forest ecosystems.

C.Most of China’s endangered plants can be found there.

D.In all about 140 kinds of birds and animals live there.

2.The discovery of some of the objects in Khami shows that the city              .

A.had a very short history

B.was ruined in the mid-16th century

C.was once Great Zimbabwe’s largest city

D.once played a great role as a trade center

3.From the passage we can learn that Henderson Island              .

A.hasn’t been greatly influenced by human activities

B.isn’t suitable for humans to live on

C.has been open to visitors for years

D.is made up of a few large atolls

4.If you are interested in religion, you should visit              .

A.http://whc.unesco.org/en/list/148

B.http://whc.unesco.org/en/list/365

C.http://whc.unesco.org/en/list/487

D.http://whc.unesco.org/en/list/637

 

查看答案和解析>>

科目:高中英語 來源:江蘇省2010屆高三下學(xué)期課堂測試練習(xí)試題英語(二) 題型:閱讀理解

III.閱讀理解

The blue tits(山雀) have been inspecting the nest-box again this year. The male is the house-hunter but the female will make the final choice. He lands at the hole and turns his head to expose his white cheeks as a signal to attract the female from where she has been feeding.

Among many birds that nest in holes, the male has a light-coloured patch on its plumage(鳥羽) which acts as signal for drawing the female’s attention to a suitable nesting-place. Unlike the blue tit, the redstart(紅尾鴝) may be only the male that strikingly coloured and the female is not beautiful.

A few years ago I was lucky enough to spot a pair of redstarts in action in a Walsh wood. The male was leading an interested female to holes that he had previously(先前) checked out. He sat at the entrance of each hole and put his head on to show off his white forehead, or his head in to reveal(顯露) his tail.

If the female failed to react to his visual signals, the male sometimes sang for extra effect, while gliding towards her on spread wings and tail. Once the female accepts by following the male through the hole the displays stop, you must be at the right place at the right time to watch them.

36. How do the blue tits choose their nest?

A. They choose their nest together.     

B. The male chooses their nest.

C. The house-hunter chooses their nest.

D. The female chooses their nest.

37. The writer was lucky to see ________.

A. how the male made his tricks

B. how an interested female played with the male happily

C. what the male displayed and won the female

D. that the male tried his best but failed to attract the female

38. You can spot a pair of redstarts in a Walsh wood ________.

A. at any time        B. regularly    C. in April    D. occasionally

39. The writer is probably ________.

A. a bird expert     B. a bird-hunter   C. a bird raiser   D. a scientist

 

查看答案和解析>>

同步練習(xí)冊答案