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?
○ 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
○ 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.
○ 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 word "preposterous" in the passage is closest in meaning to
○ unbelievable
○ inadequate
○ limited
○ creative
5. According to paragraph 3, why did Kramer use mirrors to change the apparent position of the Sun?
○ 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?
○ 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?
○ 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?
○ 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
○ 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?
○ 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?
○ 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
○ 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?
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.
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●
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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.#p#副标题#e#
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...
参考翻译：定位和导航
在南美，知更鸟每一年都会飞往春天时的北方。对于北美而言，知更鸟每年冬天又都会在南美度过简单的"假期"。甚至，它们会飞往南美几个特定的地方，然后在第二年春年又飞回到北美相同的树界范围内。问题是它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年代，一位名叫Gustave Kramer 的德国科学家给出了一些回答，意想不到地又提出新的问题。
就动物如何定位和航行的问题，Kramer发起了意义重大的新类型的研究。定位仅仅就是朝向正确的方向，而航行还涉及寻找从点A到点B的路径。
在研究早期，Kramer发现被关在笼子里的侯鸟同往常去野外开始迁徙的时候变得焦躁不安。而且，他注意到，当这些鸟在笼子里躁动不安时，它们通常会飞向迁徙路径的方向。于是，Kramer用星椋鸟做实验，将它们关在笼子里，总结出了它们的迁徙方向。事实上，它们基本都能朝向正确的迁徙方向，阴天除外。因为阴天的时候它们的骚动不安使得它们难以清楚分辨方向。因此，Kramer推测，星椋鸟 是通过太阳方位来确定方向的。为了证实这一推测，他将这些鸟的眼睛蒙住，并且用镜子改变太阳的自然方位。他发现，在这种环境下，这些鸟会依照新的"太阳"来定位。似乎它们把太阳作为一个罗盘来决定它们的方向。当时人们认为这种观点非常荒谬可笑，有些人在有地图的情况下都有可能迷路，鸟儿又怎么能够用太阳进行导航呢?很显然，接下来还需要做更多的实验。
因此，Kramer又做了外一组试验，他在鸟笼周围摆放上相同的鸟食罐，但是只有一个食罐中有食物。所有食罐的位置都是固定的，而且装有食物的那个食罐始终置于罗盘的同一个方位。但是，这个位置会随周围环境而发生变化，转动关着鸟的笼子或者背景墙都会使得这个食罐的位置相对改变。可是，只要这些鸟能够看见太阳，不管周围环境如何变化，它们都能立即找到那个装有食物的食罐。不论这些食罐是在右侧还是左侧墙壁前方，它们都没有表现出一丝疑惑。可是阴天的时候，它们就无法定位方向，很难找到装有食物的食罐。
在关于人工太阳的试验中，Kramer还有一些很有意思的发现。如果人工的太阳位置保持不变，这些星椋鸟会以每小时15°角的速度改变它们的方向，而这一速度正好是太阳在天空中运行的速度。显然，这些鸟认为它们看见的"太阳"是按照这个速度移动的。但是，当它们看见真正的太阳时，却保持了恒定的方向，正如太阳在天空中移动一样。也就是说，它们可以适应太阳的运行。这就意味着，它们形成了非常精准的生物钟。
那些在夜间迁徙的侯鸟又是怎样的呢?也许它们通过观察夜晚的天空来定向飞行。为了证实这一推测，把在夜间迁徙的侯鸟关进笼子里，并在它们的迁徙的时间段，将笼子置于一个天文馆的地板上。这个天文馆实际上是一个剧场，天花板呈穹顶状可以投射出一年四季所有夜晚的景象。当天文馆的穹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拍打着翅膀。但是当穹顶旋转时，这些鸟就会改变方向以适应这个人造天空。这就清楚地表明这些夜间迁徙的侯鸟是通过星宿位置来定位方向。
这些不断积累的证据表明鸟是通过广泛多样的外界环境信息来引导它们迁徙的。而包括磁场、地标、海岸线、声波甚至气味也被作为实验对象进行观察。由于这些数据有时会自相矛盾并且物理过程经常随着时间发生变化，使得这些研究非常的复杂。此外，一种感知能力可能会支持另一种。
星椋(liang)鸟，羽毛蓝色，有光泽，带乳白色斑点，嘴小带黄色，眼靠近嘴根，性好温暖，常群居，吃植物的果实或种子。
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