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标题: prep cr-48.。。。更看不懂了。。。。 [打印本页]

作者: wakesleep2011 时间: 2011-4-27 20:26
标题: prep cr-48.。。。更看不懂了。。。。
Parasitic wasps lay their eggs directly into the eggs of various host insects in exactly the right numbers for any suitable size of host egg. If they laid too many eggs in a host egg, the developing wasp larvae would compete with each other to the death for nutrients and space. If too few eggs were laid, portions of the host egg would decay, killing the wasp larvae.

Which of the following conclusions can properly be drawn from the information above?

(A) The size of the smallest host egg that a wasp could theoretically parasitize can be determined from the wasp's egg-laying behavior.
(B) Host insects lack any effective defenses against the form of predation practiced by parasitic wasps.
(C) Parasitic wasps learn from experience how many eggs to lay into the eggs of different host species.
(D) Failure to lay enough eggs would lead to the death of the developing wasp larvae more quickly than would laying too many eggs.
(E) Parasitic wasps use visual clues to calculate the size of a host egg.
求大牛分析解答。。。。。

作者: Kb24 时间: 2011-4-27 21:18
PW把它的蛋下在宿主的的大蛋里面（太卑鄙了）。如果小蛋下太多了，那会在大蛋里面互相竞争有限的空间和营养（注意！空间。。。）。如果小蛋下太少了，那大蛋会腐败烂掉，杀死里面的PW小蛋儿子们。
A. 根据这个PW的习惯，理论上大蛋的最小体积应该是可以推算出来的 - 正确。因为题目说了太多太少都不行，受到的是空间的限制
B. 宿主对PW的这种侵略行为无力抵抗。。。错，因为没提到
C. PW是根据经验来决定下多少蛋合适的。。。错，没提到，说不定是基因决定，WHO KNOWS
D. 下太少小蛋比下太多小蛋来说，下的太少死的更快。。。错，WHO KNOWS，说不定死的一样快
E. PW是靠视觉来计算宿主的蛋的大小。。。错，没提到，（说不定靠触觉嗅觉听觉

)

所以只有A了。。。。

作者: cptbtptp 时间: 2011-5-13 21:19
本人非NN啊，
我只能抛砖引玉说说我自己的理解
wasps 会根据eggs的大小来产下合适数量的卵，如果eggs的SIZE不合适，wasps就不会产卵，
所以wasps 产不产卵这个行为的临界点就是最小size的eggs或者是最大size的eggs。
所以选(A) The size of the smallest host egg that a wasp could theoretically parasitize can be determined from the wasp's egg-laying behavior.

作者: yangbaozi 时间: 2011-6-8 11:28

本人非NN啊，
我只能抛砖引玉说说我自己的理解
wasps 会根据eggs的大小来产下合适数量的卵，如果eggs的SIZE不合适，wasps就不会产卵，
所以wasps 产不产卵这个行为的临界点就是最小size的eggs或者是最大size的eggs。
所以选(A) The size of the smallest host egg that a wasp could theoretically parasitize can be determined from the wasp's egg-laying behavior.

-- by 会员 cptbtptp (2011/5/13 21:19:23)

为什么我的思维会这样？我觉得wasps会根据eggs的大小来下合适的数量的卵，只能说明wasps下蛋能力，但没说“如果eggs的SIZE不合适，wasps就不会产卵”。也就是我理解成“是eggs的大小影响着wasps产卵的数量，而不是wasps产卵行为选择合适大小的蛋”，所以我觉得A是推不出来的。而B，文章中都说wasps怎么确定产卵的数量，听起来让人认为宿主虫没能力抵抗wasps的产卵。

作者: sdcar2010 时间: 2011-6-8 11:57
This is a must be true type of question.

A is the correct answer. The stimulus says "

arasitic wasps lay their eggs directly into the eggs of various host insects in exactly the right numbers for any suitable size of host egg." If so, the wasp can adjust the number of eggs laid according to the size of the host egg. So you simply sit next to the host eggs and count how many eggs the parasitic wasp lays. Make a chart and compare. The host eggs receiving the lowest amount of parasit eggs would be the smallest host egg.

作者: hldada 时间: 2011-6-8 17:23
#3 楼
我觉得关键在于这句for “any ”suitable size of host egg 大黄蜂都会下自己的卵；也就是说理论上大黄蜂在所有适合尺寸的宿主的蛋里都会下卵；那也就是理论上把这些蛋集起来找打那个最小的就行啦！
而且wasp的行为怎么就体现产卵能力了能，难道宿主的蛋太小它就没能力产卵啦，不是吧！

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