托福 托福 11 - Orientation and Navigation
题目
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1.Which of the following can be inferred about bird migration from paragraph 1?
  • A.Birds will take the most direct migratory route to their new habitat.
  • B.The purpose of migration is to join with larger groups of birds.
  • C.Bird migration generally involves moving back and forth between north and south.
  • D.The destination of birds' migration can change from year to year.
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    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.

    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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    最新提问
    • wx_6697
      觉得B C 意思一样,不知道选哪个
    • wx_5576
      这道题C为什么对,E为什么不对?
    • wx_5576
      B为什么不能选啊?
    • wx_6697
      TPO30 passage 2 Q5我选的 D,不明白为啥不对?
    • wx_6697
      鑫哥,TPO6passage3Q5 答案是给错了吗?好多人都选A
    • wx_6697
      这题也很容易选错选成了D
    • wx_6697
      这道题A为什么错了
    • 芊儿
      为什么这道题不选c??a中的variety不是应该对应文中的differentiating 吗??求解!
    • wx_1000
      这道题不选E是因为太细节了吗
    • 王金阁
      这个题为什么不选C啊。。。
    • 芊儿
      这道题的D选项不是和文中的better able to reproduce in open settings相对应么??
    • 风荨火
      有大佬解释一下这个为啥选D嘛?
    • 以沫
      请问这个D 在哪里提现?为什么D错?
    • 芊儿
      第六题 的C选择为什么不对,感觉A是明显驳斥啊...
    • wx_6697
      鑫哥,这道题D是从哪里看出来的
    • wx_6697
      这题选的A,根据是Joly’s calculations clearly supported those geologists who insisted on an age for Earth far in excess of a few million years.想问鑫哥为啥不选A
    • wx_6697
      这题我选的是C依据是into a new habitat outside of its natural range, it may adapt to the new environment and leave its enemies behind.C为啥错了呢?鑫哥
    • wx_8861
      F选项的weather-related destruction在哪里体现了呢?原文最后一段的开头Among the costs里的costs是不是打错了?应该是coast?
    • wx_6697
      求问这道题B为啥不选,原文依据:viable seeds of pioneer species can be found in large numbers on some forest floors.
    • 与托福的斗争史
      与托福的斗争史 去解答 去解答
      这题为什么选C?
    • 小雨淅沥哗啦的下
      小雨淅沥哗啦的下 去解答 去解答
      B哪里错了
    • 小雨淅沥哗啦的下
      小雨淅沥哗啦的下 去解答 去解答
      B为啥不对
    • 李浩然
      B选项错误,是因为残缺么?
    • wx_100
      请问在做题的时候如何排除c呢。看了答案,感觉是该选a的,但是当时做题脑子一热,就特别钟爱c,也没看其他选项。。求敲醒。。
    • wx xxxxx
      请问鑫哥,这段开头有写As one pesticide replaces another为什么不是对应a new pesticide is developed?
    • wx_7695
      鑫哥,从哪里看出来这个masks 不是use呀,原文说了wear呀
    • haiyuqiao
      @鑫哥,这题the damage will continue 不应该对应前面的 the target species evolves resistance to it,然后As one pesticide replaces another,不应该是结束了time cycle 吗
    • wx_2065
      鑫哥,想知道E错在哪里?
    • wx_7695
      鑫哥,B选项 cannot extended to earlier geological periods. 原文说的意思是后来的进化无法估计吧
    • wx_2163
      B为什么不选
    • wx_7780
      鑫哥,这个哪里看不use了。BD是修饰错,C是无中生有,怎么能直接选出A?
    • 100
      看到第一句话,以为是中心句就选了A... 为什么不能选A呢
    • 100
      为什么选b?
    • gu33
      请问下 这里选D的原因是 因为 evolutionary approach 对应着 原文的 Rates of evolution 嘛? 这里我选了C。。不是很懂 插入句和 D的关系 求解答
    • 我是啦啦啦
      我是啦啦啦 去解答 去解答
      这个题A哪里错了?是因为主语不对吗?这个C比A多一步推理啊
    • haiyuqiao
      鑫哥,D选项里的19世纪出现了很多假设,原文中并没有提到啊
    • wx_7060
      为什么选a 呢。我觉得a是细节。F哪错了?
    • wx_1105
      我想问一下,这道题为什么不能选A呢?
    • wx_8122
      D为什么不选
    • wx_1655
      f选项哪里说了
    • chaulaw
      鑫哥,原文是below经济损害水平,D是一触发经济损害就用,这也对吗?
    • chaulaw
      interclan婚姻是对的吗?不是只在自己的family结婚扩大家族吗?
    • wx_6697
      鑫哥,这道题答案是不是错了,好多人选D 我也选的D求解答
    • wx_6697
      这道题应该是一道易错题,每个选项的都有,然而我选的A错了,求解
    • wx_6697
      鑫哥,这题的C是怎么得到的?B也没有找到啊?难道不是应该选B
    • wx_6697
      鑫哥,还有这个,好多人选A答案是不是错了
    • wx_6697
      求问D是从哪里得出来的,我选的B呀哎呀
    • wx_4185
      it is difficult to say how far they were intended to be portraits rather than generalized images 这句话怎么理解呢
    • 此楠楠
      请问下这个插入题怎么选的呢?
    • 此楠楠
      求鑫哥讲解下A选项。。。 Even though in error, Joly’s calculations clearly supported those geologists who insisted on an age for Earth far in excess of a few million years.