2015年湖北考研英語模擬試題：閱讀理解（一）

湖北2015年考研英語模擬試題：閱讀理解（一）

　　Flatfish, such as the flounder, are among the few vertebrates that lack approximate bilateral symmetry (symmetry in which structures to the left and right of the body’s midline are mirror images). Most striking among the many asymmetries evident in an adult flatfish is eye placement: before maturity one eye migrates, so that in an adult flatfish both eyes are on the same side of the head. While in most species with asymmetries virtually all adults share the same asymmetry, members of the starry flounder species can be either left-eyed (both eyes on the left side of head) or right-eyed. In the waters between the United States and Japan, the starry flounder populations vary from about 50 percent left-eyed off the United States West Coast, through about 70 percent left-eyed halfway between the United States and Japan, to nearly 100 percent left-eyed off the Japanese coast.

　　Biologists call this kind of gradual variation over a certain geographic range a “cline” and interpret clines as strong indications that the variation is adaptive, a response to environmental differences. For the starry flounder this interpretation implies that a geometric difference (between fish that are mirror images of one another) is adaptive, that left-eyedness in the Japanese starry flounder has been selected for, which provokes a perplexing question: what is the selective advantage in having both eyes on one side rather than on the other?

　　The ease with which a fish can reverse the effect of the sidedness of its eye asymmetry simply by turning around has caused biologists to study internal anatomy, especially the optic nerves, for the answer. In all flatfish the optic nerves cross, so that the right optic nerve is joined to the brain’s left side and vice versa. This crossing introduces an asymmetry, as one optic nerve must cross above or below the other. G. H. Parker reasoned that if, for example, a flatfish’s left eye migrated when the right optic nerve was on top, there would be a twisting of nerves, which might be mechanically disadvantageous. For starry flounders, then, the left-eyed variety would be selected against, since in a starry flounder the left optic nerve is uppermost.

　　The problem with the above explanation is that the Japanese starry flounder population is almost exclusively left-eyed, and natural selection never promotes a purely less advantageous variation. As other explanations proved equally untenable, biologists concluded that there is no important adaptive difference between left-eyedness and right-eyedness, and that the two characteristics are genetically associated with some other adaptively significant characteristic. This situation is one commonly encountered by evolutionary biologists, who must often decide whether a characteristic is adaptive or selectively neutral. As for the left-eyed and right-eyed flatfish, their difference, however striking, appears to be an evolutionary red herring.

　　1. According to the text, starry flounder differ form most other species of flatfish in that starry flounder

　　[A] are not basically bilaterally symmetric.

　　[B] do not become asymmetric until adulthood.

　　[C] do not all share the same asymmetry.

　　[D] have both eyes on the same side of the head.

　　2. Which of the following best describes the organization of the text as a whole?

　　[A] A phenomenon is described and an interpretation presented and rejected.

　　[B] A generalization is made and supporting evidence is supplied and weighed.

　　[C] A contradiction is noted and a resolution is suggested and then modified.

　　[D] A series of observations is presented and explained in terms of the dominant theory.

　　3. The text supplies information for answering which of the following questions?

　　[A] Why are Japanese starry flounder mostly left-eyed?

　　[B] Why should the eye-sidedness in starry flounder be considered selectively neutral?

　　[C] Why have biologists recently become interested in whether a characteristic is adaptive or selectively neutral?

　　[D] How do the eyes in flatfish migrate?

　　4. Which of the following is most clearly similar to a cline as it is described in the second paragraph of the text?

　　[A] A vegetable market in which the various items are grouped according to place of origin.

　　[B] A wheat field in which different varieties of wheat are planted to yield a crop that will bring the maximum profit.

　　[C] A flower stall in which the various species of flowers are arranged according to their price.

　　[D] A housing development in which the length of the front struts supporting the porch of each house increases as houses are built up the hill.

　　5. Which of the following phrases from the text best expresses the author’s conclusion about the meaning of the difference between left-eyed and right-eyed flatfish?

　　[A] “Most striking” (line 3, paragraph 1)

　　[B] “variation is adaptive” (line 2, paragraph 2)

　　[C] “mechanically disadvantageous” (line 7, paragraph 3)

　　[D] “evolutionary red herring” (line 9, paragraph 4)

　　[答案與考點解析]

　　1. 【答案】C

　　【考點解析】這是一道細(xì)節(jié)推導(dǎo)題。根據(jù)本題題干中的“most other species”可以把本題的答案信息來源確定在第一段的第三句，從第三句的主從句中可以歸納推導(dǎo)出本題的正確答案C。本句中的“while”一詞的含義是“雖然、盡管”，用來表達(dá)事物之間的對照對比?？忌诮忸}時一定要首先學(xué)會審題定位的基本功。

　　2. 【答案】A

　　【考點解析】這是一道文章具體寫作手法題。這是一道比較難的題型，需要考生對文章的敘述結(jié)構(gòu)有深刻的理解。本文第一段介紹了一種現(xiàn)象，第二段和第三段是生物學(xué)家對這種現(xiàn)象的解釋，第四段是本文作者對生物學(xué)家的解釋提出否定。可見本題的正確選項是A?？忌诮忸}時一定要注意文章的發(fā)展脈絡(luò)。

　　3. 【答案】B

　　【考點解析】本題是一道審題定位題型。本題的題干沒有具體給出尋找答案信息的任何線索。在這種情況下考生一定要牢記原文作者的主要意圖。具體來說，本文作者的主要意圖是要否定一些生物學(xué)家對某種生物現(xiàn)象的解釋。相關(guān)的內(nèi)容出現(xiàn)在原文第四段的首句。如果考生能夠認(rèn)識到原文第四段首句在全文中的重要性，就找到了破解本題的方法，再把第三段的尾句和第四段的第二、三句通讀并且仔細(xì)理解就會找出本題的正確答案B。當(dāng)然這是一道比較難的題目，需要考生良好的答題素質(zhì)。希望考生在迷失答題思路的時候，一定要多想一想從原文的中心主旨句和每段的段首句設(shè)法破解難題。

　　4. 【答案】D

　　【考點解析】這是一道詞匯理解題。根據(jù)原文中的“cline”一詞可迅速把本題的答案信息確定在第二段第一句。第二段第一句中的“gradual”、“geographic”、“adaptive”和“environmental differences”等詞提供了本題的正確答案D。考生在閱讀原文回答問題時，一定要學(xué)會識讀原文中的相關(guān)重要詞語。

　　5. 【答案】D

　　【考點解析】這是一道審題定位題。根據(jù)題干中的“the author’s conclusion”可將本題的答案信息迅速確定在尾段，確切地說就是尾段的最后一句?？忌欢ㄒ宄淖髡叩慕Y(jié)論一般會出現(xiàn)在全文的尾段。本題的正確答案應(yīng)該是涉及到尾段的選項D。

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