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
2013-01-28
40
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 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.
It can be inferred from the passage that the author considers Fisher’s work to be ______.
选项
A、definitive and thorough
B、inaccurate but popular, compared with Hamilton’s work
C、accurate, but trivial compared with Hamilton’s work
D、admirable, but not as up-to-date as Hamilton’s work
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/MR1O777K
0
考博英语
相关试题推荐
Thereisastoryofaverywickedmanwhodies.Beforehedied,hewas【C1】______theworstbecausetherewere【C2】______sinsheha
Onthelargeboardinthemainhalloftheairport.youcaneasilyfindthedifferentDestinations_____whichairlinescantakeyo
TheCommercialRevolutionwasnotconfined,ofcourse,tothegrowthoftradeandbanking.Includedinitalsowerefundamental
TheCommercialRevolutionwasnotconfined,ofcourse,tothegrowthoftradeandbanking.Includedinitalsowerefundamental
WhenIwaswalkingdownthestreettheotherday,Ihappenedtonoticeasmallbrownleatherwalletlyingonthesidewalk.Ipic
Thewealthofacountryshouldbemeasured_____thehealthandhappinessofitspeopleaswellasthematerialgoodsitcanprodu
EdithSmithofNewYorkwasconcernedabouther18-month-olddaughter,Amanda.Thedaughterdidnotrespondwhenherparentsspok
ThereisnoquestionbutthatNewtonwasahighlycompetentMinisteroftheMint.Itwasmainlythroughhisefforts【41】theEngli
Thegreatchariotofsociety,whichforsolonghadrundownthegentleslopeoftradition,nowfounditselfpoweredbyaninterna
Weshould______withthedoctor’srequest.
随机试题
运用成本分析模型确定最佳现金持有量时,只考虑因持有一定量现金而产生的______成本及______成本,而不考虑______和______。
舌的发育来源于
在投资决策时,投资者应当正确认识每一种证券在风险性、收益性、( )和时间性方面的特点。
公允价值是指市场参与者在计量日发生的有序交易中,出售一项资产所能收到或者转移一项负债所需支付的价格。()
A注册会计师是J公司2005年度会计报表审计的外勤审计负责人,在审计过程中,需对负责年度会计报表审计的助理人员提出的相关问题予以解答,并对其编制的有关审计工作底稿进行复核。请代为做出正确的专业判断。
旅游者的要求履约权体现在()。
简报的主体部分是报核,完整的报核包括()。
有一则箴言:“在溪水和岩石的斗争中,胜利的总是溪水,不是因为力量,而是因为坚持。”“坚持就是胜利”的哲理在于()
阅读程序:OptionBase1PrivateSubForm_Click()Dimarr,SumSum=0art=Array(1,3,5,7,9,11,13,15,17,19
ThechartbelowshowsthenumbersofChinesetouristsvisitinginBritain.Writeareportoftheinformationshownbelowabout1
最新回复
(
0
)