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
2013-01-18
57
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.
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
本题中,A、B、C三项都与文章的意思不符。综观全文,可知作者支持 Fisher的观点,但Hamilton的观点更新。因此D项为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/hH2O777K
0
考博英语
相关试题推荐
Treesthat______theviewoftheoncomingtrafficshouldbecutdown.
Sleepisafunnything.We’retaughtthatweshouldgetsevenoreighthoursanight,butalotofusgetbyjustfineonless,
Thenewspaperdidnotmentionthe______ofthedamagecausedbythefire.
Amongthemanywaysinwhichpeoplecommunicatethroughspeech,publicspeakinghasprobablyreceivedmorestudyandattractedm
Youcan______differentkindsofpeople,dictionariesorencyclopediatofindoutwhatyouwishtoknow.
Theneighbors______youverymuchforyoutospeakinthatwayaboutthem.
Ifitwereonlynecessarytodecidewhethertoteachelementarysciencetoeverycneonamassbasisortofindthegiftedfewa
TestshaveconfirmedthatfourpeopleinWisconsincontractedthemonkeypoxvirusaftercomingintoclosecontactwithpetprair
Therearethreegeneralmethodspeopleusetoexplainandunderstandtheirworld:beliefs,pseudo-science,andscience.Whata
Whyaresomeofusgoodatmath,orwriting,whileothers_____atartorbasketball?
随机试题
联合试运转费是指按照设计规定的工程质量标准,进行整个车间的有负荷和无负荷联合试运转时发生的()。
B100~50单级悬臂式离心水泵的规格是( )。
某拟建项目的建筑安装工程费为500万元,设备及工器具购置费为30万元,工程建设其它费为20万元,则该项目涨价预备费的计算基数为()万元。
《企业会计准则》包括基本准则和具体准则。()
下列关于投资冷静期的表述,说法不正确的是()。
根据我国《企业所得税暂行条例》的规定,下列各项中纳税人在计算应纳税所得额时准予扣除的税金有( )。
教育法律规范是指由国家机关制定或认可.通过国家强制力保证实施的关于教育方面的()。
国民经济效益分析中,项目的内部效益包括:()
Linux在安装了Web服务器后;当在inted下启动时,在系统文件etc/services中要添加(30),在单独运行时,命令是(31)。Web系统的系统配置文件(32)定义了服务器在DNS数据库中注册的主机名,这是通过(33)命令定义的。测试WWW服务
Tibetis______inundergroundthermalpower.
最新回复
(
0
)