首页
登录
职称英语
The evolution of sex ratios has produced, in most plants and animals with se
The evolution of sex ratios has produced, in most plants and animals with se
游客
2025-04-05
28
管理
问题
The evolution of sex ratios has produced, in most plants and animals with separate sexes, approximately equal numbers of males and females. Why should this be so? Two main kinds of answers have been offered. One is couched in terms of advantage to population. It is argued that the sex ratio will evolve so as to maximize the number of meetings between individuals of the opposite sex. This is essentially a " group selection" argument. The other, and in my view correct, type of answer was first put forward by Fisher in 1930. This "genetic" argument starts from the assumption that genes can influence the relative numbers of male and female offspring produced by an individual carrying the genes. That sex ratio will be favored which maximizes the number of descendants an individual will have and hence the number of gene copies transmitted. Suppose that the population consisted mostly of females, then an individual who produced sons only would have more grandchildren. In contrast, if the population consisted mostly of males, it would pay to have daughters. If, however, the population consisted of equal numbers of males and females, sons and daughters would be equally valuable. Thus a one-to-one sex ratio is the only stable ratio; it is an "evolutionarily stable strategy. " Although Fisher wrote before the mathematical theory of games had been developed, his theory incorporates the essential feature of a game that the best strategy to adopt depends on what others are doing.
Since Fisher’s time, it has been realized that genes can sometimes influence the chromosome or gamete in which they find themselves so that the gamete will be more likely to participate in fertilization. If such a gene occurs on a sex-determining(X or Y)chromosome, then highly aberrant sex ratios can occur. But more 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 argument, it should still 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 eggs in a given larva, it would pay her to produce one male only, because this one 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. [br] The author suggests that the work of Fisher and Hamilton was similar in that both scientists______.
选项
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 reproduction in the same animal species
答案
C
解析
从文中的最后句话“Like Fisher,Hamilton looked for an evolutionarily stable strategy,but he went a step further in recognizing that he was looking for a strategy.”可知,C项为正确答案。
转载请注明原文地址:http://tihaiku.com/zcyy/4027373.html
相关试题推荐
AtleastsincetheIndustrialRevolution,genderroleshavebeeninastate
AtleastsincetheIndustrialRevolution,genderroleshavebeeninastate
AtleastsincetheIndustrialRevolution,genderroleshavebeeninastate
AtleastsincetheIndustrialRevolution,genderroleshavebeeninastate
AtleastsincetheIndustrialRevolution,genderroleshavebeeninastate
AtleastsincetheIndustrialRevolution,genderroleshavebeeninastate
AtleastsincetheIndustrialRevolution,genderroleshavebeeninastate
AtleastsincetheIndustrialRevolution,genderroleshavebeeninastate
Theearthiswitnessinganurbanrevolution,aspeopleworldwidecrowdinto
Theearthiswitnessinganurbanrevolution,aspeopleworldwidecrowdinto
随机试题
Youmustremembernotto______fromthepointwhenyouwriteanessay.A、revolveB
Inanefforttosustaincommercialandrecreationalfishingforthenextsev
(1)JoanofArcwouldbeproud.EdithCresson,France’sfirstwomanPrimeMin
AnewstudyfromtheUniversityofNewSouthWaleshasdiscoveredthatdurin
线性光束感烟探测器按照说明书提供的方法模拟火警,探测器应发出火灾报警信号,并点亮
若f(x)为[a,b]上的连续函数,()A..小于0 B.大于0 C.等于0
测靛基质用的蛋白胨,含有大量的A.酪氨酸 B.精氨酸 C.鸟氨酸 D.苯丙
制定精神药品年度生产计划的部门为A.国务院药品监督管理部门 B.国务院卫生行政
()是税收规划最基本的原则,是税收规划与偷税漏税区别开来的根本所在。A:规划性原
如果用预置小数位数的方法输入数据时,当设定小数是“2”时,输入56789表示()
最新回复
(
0
)