首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
The evolution of sex ratios has produced, in most plants and animals with separate sexes, approximately equal numbers of males a
The evolution of sex ratios has produced, in most plants and animals with separate sexes, approximately equal numbers of males a
admin
2005-11-28
67
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)chromo-some, 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 strategy.
According to the passage, successful game strategy depends on______.
选项
A、the ability to adjust one’s behavior in light of the behavior of others
B、the degree of stability one can create in one’s immediate environment
C、the accuracy with which one can predict future events
D、the success one achieves in conserving and storing one’s resources
答案
A
解析
从文中第一段的最后一句话中“his theory incorporates the essential feature of a game--that the best strategy to adopt depends on what others are doing.”可知,A项为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/IFIO777K
0
考博英语
相关试题推荐
ElectronicCommerceAtthebeginningofthe1990s,noonehadheardoftheInternet,apartfromafewresearchersandacadem
Readthearticlebelowaboutmarketresearch.Inmostofthelines(34-45),thereisoneextraword.Itiseithergrammatical
Readthearticlebelowaboutmarketresearch.Inmostofthelines(34-45),thereisoneextraword.Itiseithergrammatical
HowtoapproachSpeakingTestPartTwo•Inthispartofthetestyougiveashorttalk(approximatelyoneminute)onabusine
HowtoapproachListeningTestPartTwo•ThispartoftheListeningTesttestsyourunderstandingofnumbers,namesandspelling
HowtoapproachListeningTestPartTwo•ThispartoftheListeningTesttestsyourunderstandingofnumbers,namesandspelling
HowtoapproachListeningTestPartTwo•ThispartoftheListeningTesttestsyourunderstandingofnumbers,namesandspell
HowtoapproachListeningTestPartTwo•ThispartoftheListeningTesttestsyourunderstandingofnumbers,namesandspell
随机试题
砂仁、白豆蔻皆可用治
除了哪味药物,入汤剂都宜先煎
A.含牙囊肿B.黏液囊肿C.牙源性钙化囊肿D.婴儿龈囊肿E.牙旁囊肿滤泡囊肿是
输卵管妊娠的根治性手术适应证不包括
波长为λ的X射线,投射到晶格常数为d的晶体上,取k=1,2,3,…,出现X射线衍射加强的衍射角θ(衍射的X射线与晶面的夹角)满足的公式为()。
()是应急救援工作的核心内容之一,其目的是为尽快地控制事故的发展,防止事故的蔓延和进一步扩大,从而最终控制住事故,并积极营救事故现场的受害人员。
某股份有限公司注册资本为5000万元人民币,董事会有5名成员,该公司应在2个月内召开临时股东大会的情形有( )。
良好的师生关系是教育教学取得成功的()。
某小型微利工业企业2012年度的相关情况如下:①产品销售收入50万元。②其他应征税的收入10万元。③销售成本、销售税金及附加45万元。④有关费用、其他支出5万元,经审查企业所得税前费用列支罚款4万元。要求:
下列古文中没有体现矛盾普遍性的是
最新回复
(
0
)