GMAT考试 4月9日更新GMAT阅读机经(六).

GMAT考试已于2012年4月2日更换题库，以下是2012年4月的GMAT阅读机经更新，更新日期从2012年4月2日起，澳际留学小编将为您提供最新的GMAT阅读机经。说明：*代表考古，绿色代表考古标志，凡是未确认的都有红标，没红标的就是已经确认了；粉色代表参考答案；红色代表重要提示；靛蓝代表参考文献，各种底色代表问题答案所对应的原文段落，详情请见问题后面的粉色描述。澳际留学在此祝大家GMAT考试顺利，得胜归来!　　

9*. 共生现象(长)

　　本篇考古非常丰富，英文原文的内容涵盖很全面，务必要看懂。整理者本人在去年11月的考试中也碰到过，请注意变体

　　V1：by walayilansusu

　　.还有一篇说两种生物共生的的现象，把生物名字忘了...有个单词不认识，说这两种生物的共生与其他的共生不一样，其他的共生比如两方都受益，或者一方建立在另一方牺牲的前提下，而这种好像是一方收益，一方无害但不受益。

　　考古(重复的很多，以下是总结)

　　P1: 科学家发现HD种类的一种P**动物喜欢抓sea butterfly放背上。这个行为很让人不解，因为P**动物这么做了之后，sea butterfly不能够吃东西，而且P**动物自己的mobility会受影响, 会在捕食和躲追杀的时候都有不便。那为什么P**动物还喜欢把sea butterfly放背上呢?

　　P2: 科学家作了一个实验，把X(捕食P**动物的一种动物)，P**还有sea butterfly三个动物放在同一个容器里，结果发现X即不吃P**动物也不吃sea butterfly，原因是sea butterfly会发出一种有毒的化学物质，所以X也就不吃背了seabutterfly的P**动物了。

　　P3，然后说他们的这个relationship 不是以及广为人知的parasitism(寄生共生), commensalism(互利共生),还有个无关共生(英文记不得了)。parasitism是一方是以另一方的伤害一次收益，commensalism是说双方相互获利，那个无关共生说他们的存在对彼此不造成影响(neutral)然后解释了下这三个的关系。然后说这个鱼和他背上的这个虾的这种关系不属于这三个范畴类，应该是个antagonism,然后说了下为什么不属于parasitism 和无关共生。这个sea butterfly和 decorator crabs还不一样，crab 随便捡周围有的东西，而seabutterfly 只捡这个虾。因为那个鱼把虾子背在背上，但是没有伤害它，不过由于虾子被背在背上，它就不能feed了。 而研究者发现，这个鱼背的虾都是活的，说明它过段时间就换个虾子。

　　Q1：.主旨题 全文应该是解释了一种phenomenon//category???

　　Q2：有个infer 题：就是通过HA不是 1 或2 种寄生你能得出什么结论? Lz选的是一个得利另一个不受伤害

　　Q3：问动物抓别的动物背着这种行为会对自己产生什么后果，A:it will bemoresubject to predation. E: it will not move as quickly as it could.主要就是这两个中间一个。

　　Q4：高亮题，全段高亮，解释第三段的作用。第三段就是解释这种现象的，说了这个现象跟之前发现的3种理论都不符合。然后给出一个新的解释

　　Q5：框架：提出现象，解释现象，总结新category

　　原题：

　　参考文献(非常重要)

　　The nature of this relationship is puzzling. It is difficult to discern how carrying another organism around can be advantageous.We speculated that in fact, amphipods mustbe considerably slowed down. By carully measuring the swimming speeds of amphipods with and without seabutterflies, we found that amphipods carrying seabutterflies moved only half as quickly as similarly sized solitary amphipods.The situation simply made nosense. In reducing their mobility, the amphipods became more vulnerable topredators and less adept at capturing prey. Why, then,would amphipods go out of their way to abduct and carry sea butterflies?

　　Our experiments clearly demonstrated that something about the sea butterflies was repelling the fish, and we suspected that this deterrence was chemical. To find out, we conducted a second set of feeding experiments. We homogenized the seabutterflies and mixed the homogenate withfish-meal powder to make food pellets. As a control, we also made food pellets containing just the fish-meal powder. We offered both the experimental and the control pellets to fish, whichalways ate the control pellets and always rejected the pellets containing the homogenate. This provided compelling evidence that compounds might beresponsible for the feeding chemical deterrence.

　　中间删去一段~没什么用

　　Our experiments demonstrated to us that the sea butterflyC. antarctica synthesizes a deterrent substance that the amphipod H. dilatata exploits for its own protection. This unique association - the abduction of one species by another - is unprecedented in the annals of behavioral and chemical ecology. Some decorator crabs are chemical ecology known to cover their upper carapace with a variety of objects,including the occasional sponge that might harbor densive chemistry. But this appears to be a nonselective behavior.Crabs haphazardly decorate themselveswith whatever is at hand.

　　The association between the sea butterfly and the amphipod falls within the dinition of symbiosis共生, where two dissimilar species live together in an intimate association. However, none ofthe relationships dined within the broad context of symbiosis - parasitism,comensalism or mutualism -appear to suitably describe the seabutterfly-amphipod relationship.

　　Parasitism寄生 implies that one species associates with another to the detriment伤害of one of them. Often, the parasite feeds off the tissues or body fluids of its host. Mutualism共生describes a relationship where both species benit from the association.Commensalism describes organisms that live in benign and neutral中立or良性association with one another. Neither of the latter two interactions appropriately describes what we have observed, and parasitism provides only avery weak analogy to it. We feel that a new term might be needed to describethe "antagonistic symbiosis" that seems to describe most accurately this unique interaction.

　　寄生:一个伤害另一个，吃对方组织和体液。共生:双方都获利。commensalism共栖:中立，互相不干扰。实际(如果加上下一段的文章):一个获利，另一个间接受害,若没有下面这段,得看选项怎么说了.网上的定义是the association is disadvantageous or destructive to one of the organisms, but ordinarily it is used of cases where the association is advantageous, or often necessary, to oneor both, and not harmful to either.

　　In this association the antagonist benits greatly from the relationship. Remember that the amphipod must sacrifice its mobility andspeed. Clearly the dense it acquires offsets these drawbacks. The seabutterfly, on the other hand, is atthe mercy of the amphipod. While it isbeing carried around, it cannot feed tosustain its energy.

　　Seabutterfly很惨.没得吃饭

　　以上就是4月9日更新的GMAT阅读机经，考生可以适当借鉴，并通过练习来掌握GMAT阅读的解题规律，从而在GMAT考试中发挥出更好的水平。 相关链接：

1.GMAT机经汇总 3月29日更新GMAT阅读机经

2.GMAT机经汇总 4月06日更新GMAT数学机经

3.GMAT考试 4月9日更新GMAT阅读机经(三)

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