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《考研英语阅读理解100篇 高分版》 Unit 18 - TEXT TWO

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2019年02月17日

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Sex is a mystery—and not just to those who indulge in it. By combining her genes with a male's, a female halves her genetic contribution to her offspring, and subsequent generations see it halved again and again. On top of that, the need for each individual to have two parents means the population can grow only half as rapidly as it otherwise might. Why, therefore, bother with the whole messy business in the first place?
Julia Jones of the University of Wales, Bangor, and her colleagues may soon have the answer to that question. They have found a species of crayfish that follows the logic of asexuality and does, indeed, clone itself. Though Dr. Jones did not actually discover this species, she was the person who identified it in the wild—in Madagascar. Her interviews suggest it was imported in about 2003, by people working on a road bypassing Antananarivo, the country's capital. As a result of this accidental import, the stage is set for an unplanned evolutionary experiment. Brute mathematics predict the new species, known as the marbled crayfish, will outcompete the locals. Those who ponder the purpose of sex, though, think the newcomer will eventually face its come-uppance.
The reason, according to those ponderers, is that the genetic diversity promoted by sex is a protection against disease. An asexual female who clones herself ten times is like someone who buys ten raffle tickets, each with the same number. A female who reproduces sexually gets only five tickets for her effort, but they are all different. This, however, is a raffle that the female wants to lose. That is because the prize is premature death for her descendants at the hands of an infection particularly adapted to the winning number—or, rather, the losing combination of genes. If this explanation is right, the marbled crayfish will do very well for an indeterminate period, and will then suddenly vanish.
At the moment, those who work in the paddy fields outside Antananarivo are enjoying the upward part of the trajectory. They are selling marbled crayfish by the condensed-milk-tin load along all the main roads from the city. And the rest of the country is likely to follow suit soon, as the crustacean now appears to be striking out from its bridgehead.
A group of experts has gathered in Antananarivo to draw up a list of questions that need researching. One of their concerns is that the marbled crayfish's sexual cousins have caused havoc elsewhere. The red swamp crayfish, for example, has tucked into the paddy fields of the Iberian peninsula with gusto, eating rice seedlings and burrowing into the banks of drainage channels, causing them to collapse. The enthusiasm that many Malagasies seem to have for spreading their new and fecund friends around the country, to provide an additional “crop”, may thus backfire.
Another worry is that the red swamp invader has helped unleash a deadly fungal disease on native crayfish populations around Europe—a plague to which it is, itself, resistant. That bodes ill for Madagascar's local species. If the theoreticians are correct, a plague will be exactly what gets rid of the newcomer, but it could also spread to the natives, reducing their numbers as well. Until then, however, the researchers can look forward to an experiment involving many a tasty barbecue.
1. The import of the marbled crayfish leads to an unplanned evolutionary experiment because _____.
[A] the reproduction model of the new species is totally different from the other existing species
[B] the new species was originally living in the wild in Madagascar which is different from the new environment
[C] the new species has never been identified before Dr. Jones' research
[D] the new species will threat the existence of the other species
2. Towards the marbled crayfish, those who ponder the purpose of the sex hold the view that _____.
[A] the marbled crayfish will outnumber the locals finally
[B] the marbled crayfish will die out after they exist for a period of time
[C] the marbled crayfish will have a lot of problems in the future
[D] the marbled crayfish will get the upper hand eventually
3. Reproduction is compared to buying raffle tickets in order to illustrate that _____.
[A] the asexual reproduction is of high risk
[B] the sexual reproduction promotes the genetic diversity
[C] the sexual reproduction is of more evolutionary advantage than the asexual reproduction
[D] the asexual reproduction is no better than the sexual reproduction
4. At present, the marbled crayfish in Antananarivo _____.
[A] is living in the upward part of the trajectory outside Antananarivo
[B] is enjoying promising market prospect in the city of Antananarivo
[C] is shrinking in quantity due to the spread of their cousin crayfish
[D] is spreading from Antananarivo to the rest of the country being packed with condensed milk
5. Which one of the following statements is TRUE of the red swamp crayfish?
[A] The red swamp crayfish is a subtype of the marbled crayfish.
[B] The red swamp crayfish carries the virus of a deadly fungal disease.
[C] Malagasy originally planned to grow the red swamp crayfish to increase the crop output.
[D] There is no doubt that the red swamp will get rid of the local species eventually.

1. The import of the marbled crayfish leads to an unplanned evolutionary experiment because _____.
[A] the reproduction model of the new species is totally different from the other existing species
[B] the new species was originally living in the wild in Madagascar which is different from the new environment
[C] the new species has never been identified before Dr. Jones' research
[D] the new species will threat the existence of the other species
1. 有大理石花纹的龙虾会引发没有预料到的进化实验,这是因为 _____。
[A] 新物种的繁殖模式和其他现存物种的模式完全不同
[B] 新物种最开始生活在马达加斯加的野外,这种环境和新环境截然不同
[C] 在Jones博士之前从未发现过这种新物种
[D] 新物种会威胁到其他物种的生存
答案:A 难度系数:☆☆
分析:细节题。根据第二段:They have found a species of crayfish that follows the logic of asexuality and does, indeed, clone itself. 说明这个物种主要是因为其繁殖方式跟以前的任何物种都不相同,是无性繁殖,也就是说,和其他现存物种的繁殖模式完全不同。选项A最为符合。选项B和D在文章中都没有对应的内容。而选项C具有一定的迷惑性,文章中指出:Though Dr Jones did not actually discover this species, she was the person who identified it in the wild—in Madagascar. 说明Jones博士不是第一个发现这个物种的人。
2. Towards the marbled crayfish, those who ponder the purpose of the sex hold the view that _____.
[A] the marbled crayfish will outnumber the locals finally
[B] the marbled crayfish will die out after they exist for a period of time
[C] the marbled crayfish will have a lot of problems in the future
[D] the marbled crayfish will get the upper hand eventually
2. 那些思考性别目的的人对于有大理石花纹的龙虾的看法是 _____。
[A] 有大理石花纹的龙虾的数量最后会超过本地龙虾
[B] 有大理石花纹的龙虾在生存一段时间后会灭绝
[C] 有大理石花纹的龙虾未来会有许多问题
[D] 有大理石花纹的龙虾最终会取得优势
答案:C 难度系数:☆☆☆☆
分析:细节题。根据第二段,这些思考研究性别作用的人认为,新物种最终需要面对自己的未来,而前面提到,数学上认为新物种的数量最终会超过老物种,末句中的though表明,这和他们的想法是相反的。因此,这些人认为有大理石花纹的龙虾未来可能会有许多问题。因此,选项C最为符合题意。
3. Reproduction is compared to buying raffle tickets in order to illustrate that _____.
[A] the asexual reproduction is of high risk
[B] the sexual reproduction promotes the genetic diversity
[C] the sexual reproduction is of more evolutionary advantage than the asexual reproduction
[D] the asexual reproduction is no better than the sexual reproduction
3. 繁殖被比喻为买彩票,这是为了说明 _____。
[A] 无性繁殖存在高风险
[B] 有性生繁殖促进基因的多样性
[C] 有性繁殖比无性繁殖在进化意义上来说具有更大的优势
[D] 无性繁殖和有性繁殖差不多
答案:A 难度系数:☆☆☆
分析:推力题。根据第三段:An asexual female who clones herself ten times is like someone who buys ten raffle tickets, each with the same number. A female who reproduces sexually gets only five tickets for her effort, but they are all different. This, however, is a raffle that the female wants to lose. 提到买彩票是为了说明遗传的多样性会降低风险,而无性繁殖就存在高风险,因此,选项A是正确答案。其他几项都与文章无关,尤其是选项C,看似符合常识,但是选择时必须以文章的内容为依据。
4. At present, the marbled crayfish in Antananarivo _____.
[A] is living in the upward part of the trajectory outside Antananarivo
[B] is enjoying promising market prospect in the city of Antananarivo
[C] is shrinking in quantity due to the spread of their cousin crayfish
[D] is spreading from Antananarivo to the rest of the country being packed with condensed milk
4. 目前,在安塔那那利佛的有大理石花纹的龙虾 _____。
[A] 生活在安塔那那利佛以外的好地方
[B] 在安塔那那利佛会有很好的市场前景
[C] 由于它们的近亲龙虾的分布范围广泛,有大理石花纹的龙虾的数量在减少
[D] 与炼乳一起包装,从安塔那那利佛扩散到这个国家的其余地区
答案:B 难度系数:☆☆☆
分析:细节题。根据第四段,第一句话说:At the moment, those who work in the paddy fields outside Antananarivo are enjoying the upward part of the trajectory”. 其实是说他们现在销量不错,随着Antananarivo市这种情况的出现,其他地方也会这样,因此,答案为B选项。A和C选项都没有依据,是对文章的误读。D选项的“condensed milk”有一定的迷惑性,但是要注意第四段提到的是“condensed-milk-tin”,是完全不一样的,与炼乳并没有关系。
5. Which one of the following statements is TRUE of the red swamp crayfish?
[A] The red swamp crayfish is a subtype of the marbled crayfish.
[B] The red swamp crayfish carries the virus of a deadly fungal disease.
[C] Malagasy originally planned to grow the red swamp crayfish to increase the crop output.
[D] There is no doubt that the red swamp will get rid of the local species eventually.
5. 关于红色沼泽龙虾,下列哪个陈述是正确的?
[A] 红色沼泽龙虾是有大理石花纹的龙虾的一种。
[B] 红色沼泽龙虾带有一种致命的真菌疾病。
[C] 马达加斯加最开始计划培育红色沼泽龙虾来增加作物的收成。
[D] 毫无疑问,红色沼泽龙虾最终会消灭其他的本地品种。
答案:B 难度系数:☆☆☆
分析:根据第五段,红色沼泽龙虾是有大理石花纹龙虾的有性繁殖近亲,因此并不是有大理石花纹龙虾的一种,选项A是错误的。选项B,第六段提到,红色沼泽龙虾入侵会带来一种致命的真菌疾病,那么可以推测,应该是它本身携带有这样的病毒。选项C, 第五段提到的“粮食”不是真正的作物。选项D,第六段提到,红色沼泽龙虾会减少本地其他物种的数量,但不一定会消灭它们。因此,选项B为正确答案。

性是个谜——不仅仅对于那些研究者来说是这样。通过将自己的基因和一个男性的基因相结合,女性就可以将自己的一半基因传给后代,而其后代又会将其基因不断二分。最为重要的是,父母两人才能繁衍出一个后代,意味着人口只能以减半的速度来繁衍。那么,为什么首先要处理这些杂乱的问题呢?
班戈区威尔士大学的Julia Jones及其同事可能很快就能给出答案了。他们发现了一种无性繁殖的龙虾,事实上,这种龙虾可以克隆自己。虽然Jones博士并不是第一个发现这个物种的人,她却是第一个在马达加斯加岛认出该物种的。她在采访中说,该物种是2003年前后由修建横穿该国首都安塔那那利佛大路的人带进来的。这种意外的进入为一个事先没有计划的进化实验创造了条件。冷冰冰的数学预言,这种长着大理石花纹的新品种龙虾的数量可能会超出本地龙虾。但是,那些思考性别目的的人认为,该新物种最终要面对自己的将来。
这些研究者认为,原因在于性别促进了遗传的多样性,这是防止疾病的一种保护措施。克隆自己10次的无性物种的雌性,就好像某人买了10注彩票,每张彩票的号码都相同。有性物种的雌性通过自己的努力只拿到5注彩票,但都是不同的。这却是雌性想要丢掉的彩票,因为奖品就是她的后代在感染疾病后会夭折,特别是对于那几张中奖的彩票来说,或者是没有基因组合。如果这种解释是正确的话,有大理石花纹的龙虾会在不确定的时期内做得非常好,然后就突然消失了。
目前在安塔那那利佛外的稻田中工作的人们享受着这其中的好处。他们使用炼乳罐沿着城市所有的主干道来售卖有大理石花纹的龙虾。这种甲壳纲动物似乎正在崭露头角,这个国家的其他地方可能很快也会效仿。
一些专家聚集在安塔那那利佛,他们列出了一系列需要研究的问题。其中一个备受关注的问题就是,这种龙虾那些有性繁殖的近亲在别的地方引起了大破坏。比如,红色沼泽龙虾已经藏到了伊比利亚岛的稻田中,吃稻米,挖下水管道,把管子弄爆。许多马达加斯加人似乎希望自己繁殖能力极强的新朋友能遍布整个国家,从而提供一种新的“粮食”,这种热情却可能事与愿违。
另外一个担忧就是,随着这种红色沼泽龙虾的侵入,一种致命的真菌疾病入侵欧洲本地龙虾,这种瘟疫本身是有抵抗力的。这预示着马达加斯加的本土物种会染上这种疾病。如果这些理论家是正确的话,那么瘟疫就是消灭这些新来物种的原因,但是也可能蔓延到本地物种的身上,从而也会减少它们的数量。但是到那时,研究者就能期望能够做一项包括了很多美味烧烤的实验。
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