托福阅读TPO30(试题 答案 译文)

托福阅读原文

【1】A heated debate has enlivened recent studies of evolution. Darwin's original thesis, andthe viewpoint supported by evolutionary gradualists, is that species change continuously butslowly and in small increments. Such changes are all but invisible over the short time scale ofmodern observations, and, it is argued, they are usually obscured by innumerable gaps in theimperfect fossil record. Gradualism, with its stress on the slow pace of change, is a comfortingposition, repeated over and over again in generations of textbooks. By the early twentiethcentury, the question about the rate of evolution had been answered in favor of gradualism tomost biologists' satisfaction.

【2】Sometimes a closed question must be reopened as new evidence or new argumentsbased on old evidence come to light. In 1972 paleontologist Stephen Jay Gould and NilesEldredge challenged conventional wisdom with an opposing viewpoint, the punctuatedequilibrium hypothesis, which posits that species give rise to new species in relativelysudden bursts, without a lengthy transition period. These episodes of rapid evolution areseparated by relatively long static spans during which a species may hardly change at all.

【3】The punctuated equilibrium hypothesis attempts to explain a curious feature of thefossil record—one that has been familiar to paleontologist for more than a century but hasusually been ignored. Many species appear to remain unchanged in the fossil record for millionsof years—a situation that seems to be at odds with Darwin's model of continuous change.Intermediated fossil forms, predicted by gradualism, are typically lacking. In most localities agiven species of clam or coral persists essentially unchanged throughout a thick formation ofrock, only to be replaced suddenly by a new and different species.

【4】The evolution of North American horse, which was once presented as a classic textbookexample of gradual evolution, is now providing equally compelling evidence for punctuatedequilibrium. A convincing 50-million-year sequence of modern horse ancestors—eachslightly larger, with more complex teeth, a longer face, and a more prominent central toe—seemed to provide strong support for Darwin's contention that species evolve gradually.But close examination of those fossil deposits now reveals a somewhat different story. Horsesevolved in discrete steps, each of which persisted almost unchanged for millions of years andwas eventually replaced by a distinctive newer model. The four-toed Eohippus preceded thethree-toed Miohippus, for example, but North American fossil evidence suggests a jerky,uneven transition between the two. If evolution had been a continuous, gradual process,one might expect that almost every fossil specimen would be slightly different from every year.

【5】If it seems difficult to conceive how major changes could occur rapidly, consider this: analteration of a single gene in files is enough to turn a normal fly with a single pair of wings intoone that has two pairs of wings.

【6】The question about the rate of evolution must now be turned around: does evolutionever proceed gradually, or does it always occur in short bursts? Detailed field studies of thickrock formations containing fossils provide the best potential tests of the competing theories.

【7】Occasionally, a sequence of fossil-rich layers of rock permits a comprehensive look atone type of organism over a long period of time. For example, Peter Sheldon's studies oftrilobites, a now extinct marine animal with a segmented body, offer a detailed glimpse intothree million years of evolution in one marine environment. In that study, each of eightdifferent trilobite species was observed to undergo a gradual change in the number ofsegments—typically an increase of one or two segments over the whole time interval. Nosignificant discontinuous were observed, leading Sheldon to conclude that environmentalconditions were quite stable during the period he examined.

【8】Similar exhaustive studies are required for many different kinds of organisms from manydifferent periods. Most researchers expect to find that both modes of transition from onespecies to another are at work in evolution. Slow, continuous change may be the normduring periods of environmental stability, while rapid evolution of new species occurs duringperiods of environment stress. But a lot more studies like Sheldon's are needed before we cansay for sure.

托福阅读试题

1.The word "innumerable" in the passage is closest in the meaning to

A.countless.

B.occasional.

C.large.

D.repeated.

2.According to paragraph 1, all of the following are true EXCEPT

A.Darwin saw evolutionary change as happening slowly and gradually.

B.Gaps in the fossil record were used to explain why it is difficult to see continuous smallchanges in the evolution of species.

C.Darwin's evolutionary thesis was rejected because small changes could not be observed inthe evolutionary record.

D.By the early twentieth century, most biologists believed that gradualism explainedevolutionary change.

3.Which of the sentences below best expresses the essential information in thehighlighted sentence in the passage paragraph 2 ? Incorrect choices change themeaning in important ways or leave out essential information.

A.The punctuated equilibrium hypothesis challenged gradualism, which holds that speciesevolve in relatively sudden bursts of brief duration.

B.The punctuated equilibrium hypothesis developed by Stephen Jay Gould and Niles Eldredgewas challenged in 1972.C.In 1972 Stephen Jay Gould and Niles Eldredge challenged gradualismby positing that change from one species to another cannot occur without a lengthytransition period.

D.The punctuate equilibrium hypothesis, in opposition to gradualism, holds that transitionsfrom one species to another occur in comparatively sudden burst.

4.According to paragraph 1 and paragraph 2, the punctuated equilibrium hypothesisand the gradualism hypothesis differed about

A.Whether the fossil record is complete.

B.Whether all species undergo change.

C.Whether evolution proceeds an a constant rate.

D.How many new species occur over long periods of time.

5.According to paragraph 3, the lack of intermediate fossils in the fossil record of somespecies

A.has been extensively studied by paleontologist for over a century.

B.contradicts the idea that most species have remained unchanged for millions of years.

C.challenges the view that evolutionary change is gradual.

D.is most common in the fossil records of clam and coral species.

6.The word "compelling" in the passage paragraph 4 is closest in the meaning to

A.surprising.

B.persuasive.

C.controversial.

D.detailed.

7.Paragraph 4 mentions that North American horses have changed in all the followingways EXCEPT in

A.the number of toes they have.

B.the length of their face.

C.their overall size.

D.the number of years they live.

8.The word "alteration" in the passage paragraph 5 is closest in meaning to

A.imperfection.

B.replacement.

C.change.

D.duplication.

9.According to paragraph 7, Peter Sheldon's studies demonstrated which ofthefollowing about trilobites?

A.They underwent gradual change over a long time period.

B.They experienced a number of discontinuous transitions during their history.

C.They remained unchanged during a long period of environmental stability.

D.They evolved in ways that cannot be counted for by either of the two competing theories.

10.The word "occasionally" in the passage paragraph 7 is closest in meaning to

A.undoubtedly.

B.basically.

C.once in a while.

D.to some extent.

11.The main purpose of paragraph 7 is to

A.Describe one test of the competing theories.

B.Provide an example of punctuated equilibrium.

C.Describe how segmented animals evidence both competing theories.

D.Explain why trilobites became extinct.

12. Look at the four squares [■] that indicate where the following sentence can beadded to the passage.Where could the sentence best fit? They believe thatenvironmental conditions may play a crucial role in determining which of the twomodes will be in operation over a given period.

■【A】Similar exhaustive studies are required for many different kinds of organisms from manydifferent periods. ■【B】Most researchers expect to find that both modes of transition fromone species to another are at work in evolution.■【C】Slow, continuous change may be thenorm during periods of environmental stability, while rapid evolution of new species occursduring periods of environment stress. ■【D】But a lot more studies like Sheldon's are neededbefore we can say for sure.

13.Directions: selected from the seven phrases below the phrases that correctlycharacterize punctuated equilibrium and the phrases that correctly characterizegradualism. Two of the phrases will not be used. This question is worth 3 points.

A.States that new species emerge from existing species during relatively brief period of time.

B.Was first formulated by Charles Darwin.

C.Explain why North American horses have become smaller over time.

D.States that new species evolve slowly and continuously from existing species.

E.Explain the lack of intermediate fossil forms in the fossil record of many species.

F.Competition is usually strongest when the density of the competing populations is the same.

G.States that a species will not change unless its environment changes.

1 )

Gradualism

A B C D E F G

2 )

punctuated equilibrium

A B C D E F G

托福阅读答案

1.innumerable是不可计数的，A是无数的，B是偶然的，C是大的，D是重复的。这个单词是numerable加否定前缀，很容易就能推出意思来。

2.A答案对应第一段第二句， B对应第一段第三句，D对应一段最后一句。C与原文冲突，原文一直在说darwin理论被人们广泛接受。

3.高亮句子的主干部分是断点平衡论挑战了原来的渐进论，然后解释了断点平衡论的内容。A选项which修饰不明，容易产生误解;B选项与原文矛盾，C与原文不符，原文S和N的观点是change的发生是withoutlengthy transition的。D和原文意思相符，并且也包含了所有的主干部分。

4.根据原文，渐进论是说物种演变是通过长时间的缓慢改变发生的;断点平衡论是说物种演变是短期爆发的。所以选择C，进化是否是匀速发生的。

5.根据lack of intermediate fossils定位到第三段倒数第二句，在往前看一句说，这一情况对于达尔文学说是不和的，而达尔文学说正是渐进论，这一段的最后也说原来的物种突然被替换，而不是渐渐进化改变的。所以C符合原文意思。 A与原文第一句破折号后矛盾，原文说这一现象一直被Ignored，B选项原文矛盾，该现象应该是反对了达尔文学说，支持了物种有长期不改变的论点。D虽然正确但是只是本段的细节，不能表达主题，所以不选。

6.Compel本身是强迫，此处作为evidence的形容词可以延伸为说服力强的。因此答案选B 有说服力的。A是惊奇的，C是有争议的，D是细节的。都不沾边。另外通过句义可以判断，前文说马的进化was once 是经典的渐进论的证明，is now(轻微转折)提了"equally"怎么样的证据证明了点断平衡论，前文既然说对gradualevolution很支持，那么后文出现equally，那应该对点断论也是有力证据。因此选B。

7.对应部分在第四段的第二句和第五句，只有D选项没有出现。

8.这一句话说一个怎么样的单一基因就足以变一个普通飞禽的一对的正常翅为两对翅膀，所以有推理应该是要改变这个基因。所以选C，Alteration是修改，变更，A选项是不完美，B是替换，D是复制 带入后都改变了原文的意思。

9.根据Peter Sheldon定位到原文第二句。后面对trilobites进行了描述，A选项对应了原文第三句，后文又继续说没有明显的断点。所以A正确。 B与原文第四句冲突。C与第三句冲突，D原文没有这种说法。而且上文也表明它符合gradual evolvement。

10.occasionally，是偶然偶尔的意思。A是毫无疑问的，B是基本上，C是偶尔有一次。D是在一定程度上。因此应该选C。并且上文提出问题说是否有过逐渐进化?那么下文给的是一个逐渐进化的例子，所以应该是在表达偶尔有一两个的意思。

11.上文说实地勘测会给competing theories提供test，第七段就给了试验例子，那么就证明是A正确。B与原文冲突，这个例子是支持渐进论的。C也不对，理由同上。D与原文目的不符。

12.首先句子开头出现了They，那么我们应该能在前文找到一个提到人物的地方，句子又提出environmentalcondition的作用，那么后文应该会出现对这一理论的解释，那么C是符合的，也可以进行代入验证。

13.A断点平衡论论点为物种变化发生突然，快速，符合。B对应文章第一段第一句话，符合渐进论。C与原文第四段第二句矛盾，原文说马进化会变大。不选。D原文第一段第一句，符合渐进论。E对应原文第三段。符合点断平衡论。F原文没提到，不选。G原文最后一段，说渐进论应该会是环境比较稳定的情况下的进化规则。符合渐进论。

托福阅读译文

【1】最近的一个关于进化的研究引发了激烈的争论。达尔文的原始论点和进化渐进主义者支持的观点是物种会持续地改变，但非常缓慢，增量也很小。这种改变是普遍的，但是现在短时间的观察是不能察觉的，并且，这个观点声称，它们通常被掩盖于不完美的化石记录的不可计数的缺失中。渐进主义及其对物种缓慢变化的引力让人欣然接受，并在世代的教科书中重复出现。在20世纪早前之前，令大部分的生物学家满足于利用渐进主义来回答关于进化速率的问题。

【2】有时，已经有了结论的问题必须由在已有证据基础上出现的新的证据和新的论点使其重新展开讨论。在1972年，古生物学者Stephen Jay Gould和 Niles Eldredge用相反的论点挑战了世俗的结论，即断点平衡说，它假设了物种演变为新的物种是通过相对突然的爆发，并非通过长时间的过渡时期。迅速的进化期被时间相对更长的静态期分开，而在静态时期，物种是几乎完全不变的。

【3】断点平衡论试着去解释化石记录的一个古怪的特点----在超过一个世纪的时间里它已经为古生物学者所熟悉，但一直被忽视。许多物种似乎在上百万年的化石记录中一直没有改变，这个情况与达尔文的模型所支持的物种的持续变化相悖。进化渐进论的支持者所预测的中间状态的化石一直没有出现。在大部分蛤和珊瑚的聚集地，其化石在很厚的岩石中都实际上没有变化，只是突然被另一新的并且不同的物种而取代。

【4】北美马的进化曾经被用作经典的教科书案例来证明渐变进化论，现在却为断点平衡学提供了同样有说服力的证据。一个有说服力的5千万年的马祖先的进化模型----每一代都稍稍大一点，有更复杂的牙齿，更长的脸，和中间更突出的脚趾----这一切都看似强有力的支持了达尔文的论点，物种是逐步地进化的。但是，对这些化石更严谨的验证现在揭示了一个不太一样的故事。马是在不连续的步骤中进化的，其中每个进化步骤中间都有上百万年时间保持不变，在最后被一个不同的更新的模型取代。比如四只脚趾的Eohippus 在三只脚趾的moihippus之前，但北美化石证据表明在这之间有一个不平稳的，不均衡的转换过程。如果进化一直都是连续，渐进的过程，人们应该预期到的是每年的化石样本都会存在细微的差别。

【5】如果很难设想大的改变会迅速发生，想想这些：一个单一基因的改变就足以将有一对翅膀的苍蝇变成两对翅膀。

【6】关于进化速度的问题现在发生了转变：进化过程是逐渐发生的么，还是总是突然短时间的爆发?对含有化石的厚岩层的细致的现场调查可以检验这两个备受争论的理论。

【7】偶尔，有一个系列的化石丰富的岩石可以允许人们综合性的观察一种生物在很长一段时间中的变化。比如，Peter Sheldon对于三叶虫，一种已灭绝的身体分节的海洋生物，的研究提供了其对三百万年来在同一海洋环境下进化的一些细节。研究中，八种三叶虫都观察到了其身体节数数量逐渐改变的过程，在整个时间段中，一般身体都增加了一到两节。没有明显的不连贯，这使sheldon得出结论：海洋环境在那段时间是比较稳定的。

【8】很多来自不同时期的不同的生物都需要开展相似的相近研究。大多数研究者希望发现物种进化的这两种模式都存在。缓慢的，连续的变化可能是在环境稳定的时间段下的规律，而快速进化的新物种则发生在环境变化时期的压力下。但是，我们需要更多的想Sheldon所做的研究以证明这个观点。
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