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Orientation and Navigation  

2013-02-19 16:49:08|  分类: 【英语资料】 |  标签: |举报 |字号 订阅

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Orientation and Navigation

To South Americans, robins are birds that fly north every spring. To North Americans, the robins simply vacation in the south each winter. Furthermore, they fly to very specific places in South America and will often come back to the same trees in North American yards the following spring. The question is not why they would leave the cold of winter so much as how they find their way around. The question perplexed people for years, until, in the 1950s, a German scientist named Gustave Kramer provided some answers and, in the process, raised new questions.

 

Kramer initiated important new kinds of research regarding how animals orient and navigate. Orientation is simply facing in the right direction; navigation involves finding ones way from point A to point B.

 

Early in his research, Kramer found that caged migratory birds became very restless at about the time they would normally have begun migration in the wild. Furthermore, he noticed that as they fluttered around in the cage, they often launched themselves in the direction of their normal migratory route. He then set up experiments with caged starlings and found that their orientation was, in fact, in the proper migratory direction except when the sky was overcast, at which times there was no clear direction to their restless movements. Kramer surmised, therefore, that they were orienting according to the position of the Sun. To test this idea, he blocked their view of the Sun and used mirrors to change its apparent position. He found that under these circumstances, the birds oriented with respect to the new "Sun." They seemed to be using the Sun as a compass to determine direction. At the time, this idea seemed preposterous. How could a bird navigate by the Sun when some of us lose our way with road maps? Obviously, more testing was in order.

 

So, in another set of experiments, Kramer put identical food boxes around the cage, with food in only one of the boxes. The boxes were stationary, and the one containing food was always at the same point of the compass. However, its position with respect to the surroundings could be changed by revolving either the inner cage containing the birds or the outer walls, which served as the background. As long as the birds could see the Sun, no matter how their surroundings were altered, they went directly to the correct food box. Whether the box appeared in front of the right wall or the left wall, they showed no signs of confusion. On overcast days, however, the birds were disoriented and had trouble locating their food box.

 

In experimenting with artificial suns, Kramer made another interesting discovery. If the artificial Sun remained stationary, the birds would shift their direction with respect to it at a rate of about 15 degrees per hour, the Sun's rate of movement across the sky. Apparently, the birds were assuming that the "Sun" they saw was moving at that rate. When the real Sun was visible, however, the birds maintained a constant direction as it moved across the sky. In other words, they were able to compensate for the Sun's movement. This meant that some sort of biological clock was operating-and a very precise clock at that.

 

What about birds that migrate at night? Perhaps they navigate by the night sky. To test the idea, caged night-migrating birds were placed on the floor of a planetarium during their migratory period. A planetarium is essentially a theater with a domelike ceiling onto which a night sky can be projected for any night of the year. When the planetarium sky matched the sky outside, the birds fluttered in the direction of their normal migration. But when the   dome was rotated, the birds changed their direction to match the artificial sky. The results clearly indicated that the birds were orienting according to the stars.

 

There is accumulating evidence indicating that birds navigate by using a wide variety of environmental cues. Other areas under investigation include magnetism, landmarks, coastlines, sonar, and even smells. The studies are complicated by the fact that the data are sometimes contradictory and the mechanisms apparently change from time to time. Furthermore, one sensory ability may back up another.

 

Paragraph 1: To South Americans, robins are birds that fly north every spring. To North Americans, the robins simply vacation in the south each winter. Furthermore, they fly to very specific places in South America and will often come back to the same trees in North American yards the following spring. The question is not why they would leave the cold of winter so much as how they find their way around. The question perplexed people for years, until, in the 1950s, a German scientist named Gustave Kramer provided some answers and, in the process, raised new questions.

 

1. Which of the following can be inferred about bird migration from paragraph 1?3

Birds will take the most direct migratory route to their new habitat.

The purpose of migration is to join with larger groups of birds.

Bird migration generally involves moving back and forth between north and south.

The destination of birds' migration can change from year to year.

 

2. The word “perplexed in the passage is closest in meaning to (3)

defeated

interested

puzzled

occupied

 

Paragraph 3: Early in his research, Kramer found that caged migratory birds became very restless at about the time they would normally have begun migration in the wild. Furthermore, he noticed that as they fluttered around in the cage, they often launched themselves in the direction of their normal migratory route. He then set up experiments with caged starlings and found that their orientation was, in fact, in the proper migratory direction except when the sky was overcast, at which times there was no clear direction to their restless movements. Kramer surmised, therefore, that they were orienting according to the position of the Sun. To test this idea, he blocked their view of the Sun and used mirrors to change its apparent position. He found that under these circumstances, the birds oriented with respect to the new "Sun." They seemed to be using the Sun as a compass to determine direction. At the time, this idea seemed preposterous. How could a bird navigate by the Sun when some of us lose our way with road maps? Obviously, more testing was in order.

 

 

3. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.4

Experiments revealed that caged starlings displayed a lack of directional sense and restless movements.

Experiments revealed that caged starlings were unable to orient themselves in the direction of their normal migratory route.

Experiments revealed that the restless movement of caged starlings had no clear direction.

Experiments revealed that caged starlings' orientation was accurate unless the weather was overcast.

 

4. The wordpreposterous in the passage is closest in meaning to 1

unbelievable

inadequate

limited

creative

 

5. According to paragraph 3, why did Kramer use mirrors to change the apparent position of the Sun?2

To test the effect of light on the birds' restlessness

To test whether birds were using the Sun to navigate

To simulate the shifting of light the birds would encounter along their regular migratory route

To cause the birds to migrate at a different time than they would in the wild

 

6. According to paragraph 3, when do caged starlings become restless?3

When the weather is overcast

When they are unable to identify their normal migratory route

When their normal time for migration arrives

When mirrors are used to change the apparent position of the Sun

 

Paragraph 4: So, in another set of experiments, Kramer put identical food boxes around the cage, with food in only one of the boxes. The boxes were stationary, and the one containing food was always at the same point of the compass. However, its position with respect to the surroundings could be changed by revolving either the inner cage containing the birds or the outer walls, which served as the background. As long as the birds could see the Sun, no matter how their surroundings were altered, they went directly to the correct food box. Whether the box appeared in front of the right wall or the left wall, they showed no signs of confusion. On overcast days, however, the birds were disoriented and had trouble locating their food box.

 

7. Which of the following can be inferred from paragraph 4 about Kramer s reason for filling one food box and leaving the rest empty? 2

He believed the birds would eat food from only one box.

He wanted to see whether the Sun alone controlled the birds' ability to navigate toward the box with food.

He thought that if all the boxes contained food, this would distract the birds from following their migratory route.

He needed to test whether the birds preferred having the food at any particular point of the compass.

 

Paragraph 5: In experimenting with artificial suns, Kramer made another interesting discovery. If the artificial Sun remained stationary, the birds would shift their direction with respect to it at a rate of about 15 degrees per hour, the Sun's rate of movement across the sky. Apparently, the birds were assuming that the "Sun" they saw was moving at that rate. When the real Sun was visible, however, the birds maintained a constant direction as it moved across the sky. In other words, they were able to compensate for the Sun's movement. This meant that some sort of biological clock was operating-and a very precise clock at that.

 

8. According to paragraph 5, how did the birds fly when the real Sun was visible?1

They kept the direction of their flight constant.

They changed the direction of their flight at a rate of 15 degrees per hour.

They kept flying toward the Sun.

They flew in the same direction as the birds that were seeing the artificial Sun.

 

9. The experiment described in paragraph 5 caused Kramer to conclude that birds possess a biological clock because 1

when birds navigate they are able to compensate for the changing position of the Sun in the sky

birds innate bearings keep them oriented in a direction that is within 15 degrees of the Suns direction

birds' migration is triggered by natural environmental cues, such as the position of the Sun

birds shift their direction at a rate of 15 degrees per hour whether the Sun is visible or not

 

Paragraph 6: What about birds that migrate at night? Perhaps they navigate by the night sky. To test the idea, caged night-migrating birds were placed on the floor of a planetarium during their migratory period. A planetarium is essentially a theater with a domelike ceiling onto which a night sky can be projected for any night of the year. When the planetarium sky matched the sky outside, the birds fluttered in the direction of their normal migration. But when the dome was rotated, the birds changed their direction to match the artificial sky. The results clearly indicated that the birds were orienting according to the stars.

 

10. According to paragraph 6, how did the birds navigate in the planetarium's nighttime environment?3

By waiting for the dome to stop rotating

By their position on the planetarium floor

By orienting themselves to the stars in the artificial night sky

By navigating randomly until they found the correct orientation

 

11. Which of the following best describes the author's presentation of information in the passage? 1

A number of experiments are described to support the idea that birds use the Sun and the night sky to navigate.

The author uses logic to show that the biological clock in birds is inaccurate.

A structured argument about the importance of internal versus external cues for navigation is presented.

The opposing points of view about bird migration are clarified through the study of contrasting experiments.

 

Paragraph 7: There is accumulating evidence indicating that birds navigate by using a wide variety of environmental cues. Other areas under investigation include magnetism, landmarks, coastlines, sonar, and even smells. The studies are complicated by the fact that the data are sometimes contradictory and the mechanisms apparently change from time to time. Furthermore, one sensory ability may back up another.

 

12. The word “accumulating in the passage is closest in meaning to 2

new

increasing

convincing

extensive

 

 

Paragraph 4: So, in another set of experiments, Kramer put identical food boxes around the cage, with food in only one of the boxes. The boxes were stationary, and the one containing food was always at the same point of the compass. However, its position with respect to the surroundings could be changed by revolving either the inner cage containing the birds or the outer walls, which served as the background. As long as the birds could see the Sun, no matter how their surroundings were altered, they went directly to the correct food box. Whether the box appeared in front of the right wall or the left wall, they showed no signs of confusion. On overcast days, however, the birds were disoriented and had trouble locating their food box.

 

13. Look at the four squares [] that indicate where the following sentence could be added to the passage.

He arranged the feed boxes at various positions on a compass.

Where would the sentence best fit?1

 

14.Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

 

Gustave Kramer conducted important research related to the ability of birds to orient and navigate.

Because caged birds…

Kramer demonstrated that…

Kramer showed that...

Answer Choices

Because caged birds become disoriented when the sky is overcast, Kramer hypothesized that birds orient themselves according to the Sun's position.

In one set of experiments, Kramer placed the box containing food at the same point of the compass each time he put food boxes in the birds’ environment.

Kramer demonstrated that an internal biological clock allows starlings to compensate for the Sun's movement.

After several studies, Kramer surmised that an internal biological clock allows some species of birds to navigate at night.

The role of environmental cues in birds' navigation is clear, for on overcast days, birds use objects besides the Sun to orient themselves.

Kramer showed that night-migrating birds use the sky to navigate by the stars.


 

  

参考答案:

1. 3

2. 3

3. 4

4. 1

5. 2

6. 3

7. 2

8.1

9. 1

10. 3

11. 1

12. 2

13. 1

14. Because caged birds…

Kramer demonstrated that…

Kramer showed that...


 

参考译文:定位和导航

在南美,知更鸟每年春天都会飞往北方。而在北美,知更鸟每个冬天又都会往南飞。而且,他们会飞往几个固定的位于南美的地方,然后在第二年春年又会回到在北美原来的那些树上。问题是他们为什么会在寒冷的冬天离开,然后又是怎样找到迁徙的路径的。这个问题困扰了人们很久,直到1950年,一个叫做Gustave Kramer 的德国科学家回答了这个问题。但同时,又提出新的问题。

 

Kramer提出了新的重要的关于动物如何定位和航行的研究。定位就是面朝正确的方向,航行包括了找到从A点到B点的路径。

 

在这些研究的早期,Kramer发现被关在笼子里有迁徙习惯的鸟在他们往常在野外应该开始迁徙的时候变得好动。而且,他注意到,当这些鸟在笼子里躁动不安时,他们通常将自己推向通常的迁徙路径的方向。他于是将星椋鸟关在笼子里做实验,然后发现了他们的方向。事实上,他们有在适当的迁徙方向,除了天空多云时,因为这个时候往往使得他们的骚动不安的活动没有了清楚地方向指向。因此,Kramer猜测道,他们时通过太阳的方位来确定方向的。为了验证这个猜想,他蒙住他们的眼睛并且用镜子改变太阳的自然方位。他发现,在这种环境下,这些鸟按照新的太阳来定位。似乎他们把太阳作为一个罗盘来决定他们的方向。在那个时候,这种猜想看上去是荒谬的,当我们中的一些在有地图的情况下都会走失他们又怎么能够用太阳进行导航呢?显而易见的,接下来会有更多的实验。

 

所以,在另外一组试验中,Kramer在鸟笼周围放置了相同的餐盒,但是只有一个餐盒中有食物。这些餐盒是静止的,装有食物的那个餐盒始终在罗盘的同一个地点。但是,这个点会由于周围的环境而发生相对改变,那就是既可以通过旋转装有鸟的内部笼子或者旋转作为背景的外墙。只要这些鸟可以看见太阳,无论他们身处的环境如何变化,他们都为径直找到那个正确的餐盒。无论这些盒子是在左墙还是右墙前方,他们都没有表现出迷惑的样子。但是,在阴天,他们就不能定位并且有困难发现盛有食物的餐盒。

 

在关于人造太阳的试验中,Kramer又有一些有意思的发现。如果人工太阳保持静止,这些鸟会每小时以15°的速度去改变他们的方向,这个速度正是太阳在天空中运动的速度。显然,这些鸟认为他们所看见的“太阳”是按照这个速度移动的。但是,当看见真正的太阳时,这些鸟保持了连贯的方向,正如太阳在天空中移动一样。也就是说,他们可以适应太阳的运动。这就意味着,有一种非常精准的生物钟在起着作用。

 

那些在夜晚迁徙的鸟又是怎样的呢?也许他们通过夜晚的天空来航行。为了验证这个猜想,这些在夜晚迁徙的鸟被关进笼子里,并在他们的迁徙期放置在一个天文馆里。这个天文馆是一个具有穹顶状的天花板的剧场,并且这些天花板可以放映出一年中任何夜晚的样子。当天文馆的屋顶与外面的天空相吻合时,这些鸟就会朝着往常迁徙的方向振翅。但是当这个圆屋顶旋转的时候,这些鸟改变方向以适应这个人造天空。这就清楚地表明这些鸟是通过星星来进行方向定位的。

 

这些不断积累的证据表明鸟是通过非常多的外界环境信息来引导他们的航行的。包括磁场、地理标识、海岸线、声波甚至气味也同样被作为实验对象进行观察。由于这些数据常常是相反的并且磁场经常随着时间的改变而改变的事实,使得这些研究非常的复杂。此外,一种知觉能力可能会支持另一种。


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