GRE阅读题目解析:寄生性胡蜂种群

　　P1

　　Questions 1 to 3 are based on the following reading passage.

　　Immediately relevant to game theory are the sex ratios in certain parasitic wasp species that have a large excess of females. In these species, fertilized eggs develop into females and unfertilized eggs into males. A female stores sperm and can determine the sex of each egg she lays by fertilizing it or leaving it unfertilized. By Fisher‘s genetic argument that the sex ratio will be favored which maximizes the number of descendants an individual will have and hence the number of gene copies transmitted, it should pay a female to produce equal numbers of sons and daughters. Hamilton, noting that the eggs develop within their host—the larva of another insect—and that the newly emerged adult wasps mate immediately and disperse, offered a remarkably cogent analysis. Since only one female usually lays eggs in a given larva, it would pay her to produce one male only, because this one male could fertilize all his sisters on emergence. Like Fisher, Hamilton looked for an evolutionarily stable strategy, but he went a step further in recognizing that he was looking for a strategy.

　　1. The author suggests that the work of Fisher and Hamilton was similar in that both scientists

　　(A) conducted their research at approximately the same time

　　(B) sought to manipulate the sex ratios of some of the animals they studied

　　(C) sought an explanation of why certain sex ratios exist and remain stable

　　(D) studied game theory, thereby providing important groundwork for the later development of strategy theory

　　(E) studied reproduction in the same animal species

　　(For the following question, consider each of the choices separately and select all that apply)

　　2. The passage contains information that would answer which of the following questions about wasps?

　　A How many eggs does the female wasp usually lay in a single host larva?

　　B Can some species of wasp determine sex ratios among their offspring?

　　C What is the approximate sex ratio among the offspring of parasitic wasps?

　　3. Which of the following is NOT true of the species of parasitic wasps discussed in the passage?

　　A) Adult female wasps are capable of storing sperm.

　　B) Female wasps lay their eggs in the larvae of other insects.

　　C) The adult female wasp can be fertilized by a male that was hatched in the same larva as herself.

　　D) So few male wasps are produced that extinction is almost certain.

　　E) Male wasps do not emerge from their hosts until they reach sexual maturity.

　　P1

　　1

　　Immediately relevant to game theory are the sex ratios in certain parasitic wasp species that have a large excess of females.

　　某些寄生性胡蜂种群内雌性的数量远超雄性，这种性别比与博弈论紧密相关。

　　(game theory：博弈论)

　　2

　　In these species, fertilized eggs develop into females and unfertilized eggs into males.

　　在这些种群内，受精卵发育为雌蜂，而未受精卵发育为雄蜂。

　　3

　　A female stores sperm and can determine the sex of each egg she lays by fertilizing it or leaving it unfertilized.

　　雌蜂携带精子，能够通过选择是否让其受精，来决定它产的每一枚卵的性别。

　　4

　　By Fisher‘s genetic argument that the sex ratio will be favored which maximizes the number of descendants an individual will have and hence the number of gene copies transmitted, it should pay a female to produce equal numbers of sons and daughters.

　　F 的遗传学观点认为，让每一个体产生最多后代，且因此(最大程度)传播自身基因的性别比，最具竞争优势，生育数量相当的两种性别的后代，对雌蜂是最有利的。

　　(pay 【MWC】to return value or profit to 回报…，有利于…)

　　5

　　Hamilton, noting that the eggs develop within their host — the larva of another insect — and that the newly emerged adult wasps mate immediately and disperse, offered a remarkably cogent analysis.

　　注意到卵都在宿主体内 —— 另一种昆虫的幼虫 —— 发育，而且新生的蜂成熟后立刻交配并离开，H 提出了一种相当有说服力的分析。

　　6

　　Since only one female usually lays eggs in a given larva, it would pay her to produce one male only, because this one male could fertilize all his sisters on emergence.

　　既然每只被寄生的幼虫里只有一只雌蜂产卵，则只生产一只雄蜂最有利，因为这只雄蜂已经足够为它所有的姐妹提供精子。

　　7

　　Like Fisher,Hamilton looked for an evolutionarily stable strategy, but he went a step further in recognizing that he was looking for a strategy.

　　H 和 F 都寻找一种进化论意义上的稳定策略，但 H 更进一步，他意识到自己在寻找这样一种策略。

　　1. The author suggests that the work of Fisher and Hamilton was similar in that both scientists

　　(A) conducted their research at approximately the same time

　　(B) sought to manipulate the sex ratios of some of the animals they studied

　　(C) sought an explanation of why certain sex ratios exist and remain stable

　　(D) studied game theory, thereby providing important groundwork for the late development of strategy theory

　　(E) studied reproduction in the same animal species

　　选 C

　　根据句 7：

　　Like Fisher,Hamilton looked for an evolutionarily stable strategy, but he went a step further in recognizing that he was looking for a strategy.

　　所以选 C，“他们都尝试解释为什么这些寄生蜂种群内有特定的性别比，且能保持这个比例稳定。”

　　A 未知。

　　B 错在 manipulate 。

　　D 说反了，应该说他们都试图用博弈论来解释同一种科学发现。

　　E 这项没什么错，但显然不是最佳答案，正如我们不应该把 “他们都是人” 或 “他们都是科学家” 作为他们的共同点一样。

　　For the following question, consider each of the choices separately and select all that apply

　　2. The passage contains information that would answer which of the following questions about wasps?

　　A How many eggs does the female wasp usually lay in a single host larva?

　　B Can some species of wasp determine sex ratios among their offspring?

　　C What is the approximate sex ratio among the offspring of parasitic wasps?

　　不定项选择，有时候真的会选3个。

　　选 B

　　A 未知信息。

　　B 根据句 3：

　　A female stores sperm and can determine the sex of each egg she lays by fertilizing it or leaving it unfertilized.

　　C 我们知道一个寄主内有一只雄蜂，但不知道寄主内雌蜂的数量，所以不能确定性别比。

　　3. Which of the following is NOT true of the species of parasitic wasps discussed in the passage?

　　(A) Adult female wasps are capable of storing sperm.

　　(B) Female wasps lay their eggs in the larva of other insects.

　　(C) The adult female wasp can be fertilized by a male that was hatched in the same larva as herself.

　　(D) So few male wasps are produced that extinction is almost certain.

　　(E) Male wasps do not emerge from their hosts until they reach sexual maturity.

　　选 D

　　A

　　句 3：

　　A female stores sperm and can determine the sex of each egg she lays by fertilizing it or leaving it unfertilized.

　　B

　　句 5：

　　…… within their host — the larva of another insect — and that ……

　　C

　　句 6：

　　Since only one female usually lays eggs in a given larva, it would pay her to produce one male only, because this one male could fertilize all his sisters on emergence.

　　D

　　… extinction is almost certain，一看就废了。

　　E

　　句 5：

　　… newly emerged adult wasps mate immediately and disperse …