Sexual Selection in Males and Females

Sexual selection was an idea proposed by Darwin and refers to the process in which males and females attempt to maximize their chances of reproductive success. Within a species there are certain characteristics that make individuals attractive to potential mates. An example of this is in peacocks, female peacocks are attracted to males with long brightly colored tails, even though this makes them easier to be spotted by predators. This characteristic then evolves within the species due to how males with this characteristic have a higher chance of reproductive success and their characteristics being passed on to surviving offspring.
There are 2 types of sexual selection. Intersexual selection takes place when males compete for the attention of a female. The female will play an active role in choosing her mate and will choose the mate with the best characteristics in order to produce the offspring with the best characteristics. The other type is Intrasexual selection. This takes place when males compete against each other and are rewarded with the female. The female plays a passive role in this. An example of intrasexual selection is Short’s sperm competition.
This suggests that males are motivated to ensure that their sperm is successful in fertilization and can compete against other males. This is essential due to how in some species the female will mate with a number of different males so the male with the best fertilizing sperm will win. In humans this has resulted in men evolving to release much larger amounts of sperm after ejaculation to help increase the likelihood of fertilization. Harvey and May suggested that ethic differences in testicle size may reflect adaptive differences in mating strategies within different populations.

Samples showed that Chinese mens testicles were approximately half the size Danish mens testicles. This means a chinese man will be at a disadvantage if the female mates with a numerous amount of males and will most likely enter a long term relationship in order to create offspring. Males are more likely to use short term mating strategies as a form of producing offspring due to how they have an unlimited amount of sperm compared to women who have limited amount of reproductive opportunities.
Clark and Hatfield helped support this by getting female and male experiments to ask male and female participants if they would like to engage in casual sex. 75% of males said yes while every female participant said no. This helps support the sexual selection theory as it shows that females have to be more careful with mating as they only have a limited amount of opportunities therefore are more likely to enter a longterm mating strategy. Males can have casual sex with little investment so are more likely to then females. This study helps to show the gender differences.
Much of the research documenting sex differences in mate choice focus on preferences rather than on real life choices. So a male may have a preference but may have to settle for much less. Mate choice is a product of mate preferences form in the environment of evolutionary adaptiveness (EEA). Sexual selection suggests that females prefer males who they can gain benefits from such as gifts. This is shown in male birds who make nests for females in order to mate with them and also in insects who give nuptial gifts. Sexual selection also suggests that females prefer males who have a strong jawline and prominent cheekbones.
These characteristics arise because of a strong presence of testosterone which also helps to indicate fertility within males. Penton-voack found that during a women’s most fertile time in her menstrual cycle they preferred a male whose face shape was more masculinised (strong jawline etc.. ) Suggesting that females like males who show high levels of testosterone, supporting sexual selection theory. Buss explored whether there were universals of human mate preference. His research pned across 37 cultures and involved 10 thousand participants of different religion,ethnic and economic groups, increasing the validity of the study.
He then made the study even more ecologically valid by varying the sampling procedure per culture. Results showed that women in all cultures show a preferences for men with resources while males placed more emphasis on women’s attractiveness as it is an emphasis on their physical health. This supports the claims made by the sexual selection theory that women will form relationships with men for resources as it will benefit them and increase the survivability of their offspring which is a woman’s main evolutionary goal.
A problem is in some cultures arranged marriages is the normal and individuals have no choice on their mate as it is already chosen by their parents, so the studies validity can be questioned as this will affect the results obtained. Buss further helped to supported mate choice by looking at real marriages. He found that when males divorce many of them go for younger women when they choose to marry again. This is due to how men will want to be in a relationship with women in their most fertile age and the younger the woman is the more chance of reproductive success the male his.
This helps to support the evolutionary theory that a mans main goal is to produce as many surviving offspring as possible. The evolutionary approach can be seen as deterministic due to how it suggests our genes specify exactly how we will behave. The approach fails to take into account that our genes are not the only thing that determine how we behave, the environment in which we grew up in will also have an effect on us. This is known as the nature vs nurture debate where it is argued if our biological factors or the way in which we are brought up makes up how we behave when we grow up.
The evolutionary theory suggests that rape is an evolved and adaptive behaviour which enhance reproductive success. Sterglanz and Nash suggest that the theory offers justification for rape as it explains why males who can’t compete with other males for resources and women will produce offspring. This is socially sensitive and has been met by much hostility from the general public and women psychologists due to how it is an issue which negatively affects the lives of many.
The evolutionary theory is also seen as reductionist as it explains humans reproductive behaviors as a result of our genes, ignoring the environmental actors which also decide our behavior. The approach also ignores homosexual relationships and only accounts for heterosexual relationships and the roles in which men and women take. To conclude the sexual selection theory helps to explain that males and females attempt to maximize their reproductive success by getting with a partner with certain characteristics, these characteristics will then evolve over time due to how individuals in a species with these characteristics will have a higher chance of reproductive success