托福 新托福 58 - Pinyon Pines and Pinyon Jays
题目
1 2 3 4 5 6 7 8 9 10 11 12 13 14
13.Look at the four squares [■]that indicate where the following sentence could be added to the passage.Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.
As a result, less energy will be needed to produce a crop of seeds large enough to flood the reduced market for them.
正确答案:
答案解析:
答题统计
答题统计

登录 后才可以查看答案解析,还没有账号?

还没有账号?马上 注册 >>

阅读原文 中文译文

Organisms of different species frequently evolve adaptations that make them utterly and specifically dependent on each other for resources. For example, many trees must have mycorrhizal fungi living in their root systems, fungi that are indispensable to the tree because they facilitate mineral uptake from the soil. In turn, the fungi rely on the trees to photosynthesize: they use some of the tree's chemical food as their only energy source. Such intimate relationships are examples of coevolution through which two species become so interdependent that they can thrive only in each other' s presence.

At first glance, the relationship between pinyon pine trees and the pinyonJay does not appear to be one of coevolution. Pinyon pines produce cones and seeds that attract seed predators, especially the pinyon jay. A seed, of course, contains an embryonic plant for the next generation. Why sacrifice it to an animal? Some plants have poisonous seeds, an obvious adaptation to reduce loss to animals. Pinyons, however, have an array of characteristics that combine to encourage jays to visit the pines and help themselves to the seeds. Cones are positioned upward and outward on the tree, so the seeds inside are in plain sight of the jays, essentially inviting them to partake: Pinyon seeds are unusually large, and each seed is high in energy. The seed coat is thin, meaning that birds such as pinyon jays can not only ingest the seeds but also digest them. In many plants, an indigestible seed coat permits the seed to pass unharmed through the bird' s alimentary system. Pinyon seed coats differ in color between edible and nonviable seeds, signaling the jays as to which they should select.

Attracting seed predators would not seem to be a successful survival strategy for pinyon pines. However, pinyon jays are behaviorally adapted to bury any seeds in excess of their immediate survival needs. This is a useful behavior for the jays, providing they can retrieve some of the buried seeds during winter, and good for the trees, as the unretrieved seeds are ready to germinate. Still, for the jays to bury any seeds, there must be an abundance of seeds far beyond the jays' immediate needs. One tree could never produce ,so many seeds, but if all the pinyons in a region produced heavy seed crops at once, they would indeed "flood the market" with vastly more pinyon seeds than the local population of jays could consume In fact, that is exactly what the pinyon pines do.

It requires a great deal of energy to make so many seeds, so much energy that it is unlikely that a pinyon population could produce such a bumper seed crop every year. More important, however, it would be to the severe disadvantage of the trees to produce large seed crops annually, even if they could. Doing so would make the resource not only abundant but also predictable Seed predators could, over the years, steadily build their populations, eventually increasing so much that they could, indeed, consume virtually all of the seeds. It is much more adaptive for the plants to produce seed cornucopias intermittently. Doing so has several major advantages. First, energy can be stored for some years and then devoted to cone and seed production, ensuring adequate energy to produce a large seed crop. Second, seed­predator populations will decline in years of low seed production, either through starvation, reduced reproduction, or emigration. Pinyons in most areas have a roughly six-year interval between heavy seed crops.

Pinyan jays have so completely adapted to the cycle of the pinyons that their reproduction is tied to it. Most species of birds mature sexually in response to changes in day length. In pinyon jays, however, day length is only one stimulus for reproduction. The other cue is availability of pinyon seeds. When seeds are abundant, jays can breed very early in spring continue breeding through summer, and reenter breeding condition as early as the winter solstice. So the jay population temporari'ly enlarges in response to one of the intermittent large crops of pinyon seeds. But the increase in the population of jays is less than the increase in the size of the seed crop. Thus many of the seeds of a bumper crop are buried and subsequently germinate, many more than would germinate without planting by the jays.

留言区中有很多我们对问题的解答喔, 登录后可以查看

还没有账号?马上 注册 >>

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.