Evolutionary Theory

• Sexual selection explains the evolution of characteristics that confer a reproductive advantage rather than a survival advantage
• This refers to characteristics that allow an individual to have more offspring
• Reproductive success can be measured in terms of how many offspring are left behind and their probable fitness
• Anisogamy refers to the differences between male and female sex cells
• Male gametes are small, highly mobile and created continuously in vast numbers. Sperm is produced from puberty to age which means males are fertile through their lives
• Female gametes are relatively large, static and produced at regular intervals. They’re only produced for a limited number of fertile years which means female fertility declines with age
• A consequence of anisogamy for mate selection is that there’s no shortage of fertile males, but a fertile woman is a rarer ‘resource’
• Due to anisogamy, men and women are subject to different evolutionary pressure which give rise to different strategies and behaviours to maximise their reproductive potential
• Intra-sexual selection is when members of the same sex compete for the attentions of and access to members of the opposite sex. the winner is then able to mate with the female, passing on his genes to the next generation
• Inter-sexual selection is when one sex is choosy about picking a partner, therefore the opposite sex develops traits that are attractive so they’re chosen
• Males look for females with characteristics that suggest fertility and features that suggest suitability for pregnancy
• Natural selection favours male behaviours maximising the number of potential pregnancies
• Women invest a great deal in every child they have, therefore it’s important to mate with a partner who can help the child to survive
• Women are interested in mates with resources or abilities to gain resources which suggests that the male is able to take care of the female and their children
• Natural selection favours female behaviours maximising the number of potential pregnancies through careful mate selection and monogamy
• Females use courtship rituals to select males on the basis of reproductive fitness through males demonstrating strength, health and the ability to provide resources. Prolonged courtship rituals also benefit females as they make males invest time, effort and resources increasing the chances of a male not deserting her after successful mates
• Due to the fact that men and women experience different evolutionary pressure, this leads to different behavioural strategies in men and women to ensure reproductive success
• Buss (1989) aimed to investigate the characteristics people value in potential mates and whether these correspond to evolutionary theory. He found that males in all 37 cultures rated ‘good looking’ to be the most important and in 36/37 cultures females wanted their mate to have ‘good financial prospects’
• Singh (1993) used data from 50 years of beauty contest winners and playboy centrefolds to assess the waist to hip ratio of women. They found that WHR of 0.7 was a consistent feature of female attractiveness which suggests that WHR is an important bodily feature associated with physical attractiveness in women, as well as their reproductive potential
• Swami and Furnham (2006) found that the optimum WHR ratio of 0.7 corresponds closely to popular supermodels, therefore supporting Singh’s findings
• Davies (1990) found that men looked for health and attractiveness, while offering wealth and resources. Females however, looked for resources and status, while offering beauty and youth
• Dunbar (1995) analysed 900 personal advertisements from four US newspapers. 42% of males and 25% of females sought youthfulness. 44% of men and 22% of women sought attractiveness