Relationships- Sexual Selection & Human Reproductive Behaviour Flashcards
Sexual selection -
An evolutionary explanation of partner preference. Attributes or behaviours that increase reproductive success are passed on and may become exaggerated over succeeding generations of offspring.
Human reproductive behaviour -
This refers to any behaviours which relate to opportunities to reproduce and thereby increase the survival chances of our genes. It includes the evolutionary mechanisms underlying our partner preferences, such as mate choice and mate competition.
What is sexual selection?
Sexual selection explains why some characteristics that might appear disadvantageous actually confer an advantage in human reproductive behaviour because the characteristics are attractive to potential mates or provide an advantage over competitors for reproductive rights. Examples in humans include greater height, secondary sexual characteristics, and certain facial and bodily features.
What is anisogamy?
Anisogamy refers to the differences between male and female sex cells (gametes). Male gametes (sperm) are small, highly mobile, produced continuously in vast numbers, and require little energy to produce. Female gametes (eggs or ova) are large, static, produced at intervals for a limited number of fertile years, and require a significant energy investment.
What are the consequences of anisogamy for mate selection?
Anisogamy leads to a shortage of fertile females compared to fertile males, making fertile females a rare ‘resource’. It also gives rise to two different mating strategies, resulting in two types of sexual selection: inter-sexual and intra-sexual selection.
What is inter-sexual selection?
Inter-sexual selection is the preferred strategy of females, focusing on quality over quantity. Females select genetically fit partners who can provide resources, as they invest more time, energy, and resources in reproduction. This leads to males competing for the opportunity to mate with fertile females.
What is intra-sexual selection?
Intra-sexual selection is the preferred strategy of males, focusing on quantity over quality. It involves competition among males to mate with females. The winner passes on characteristics that contributed to his victory, leading to dimorphism in humans, such as larger male size.
What is the runaway process in sexual selection?
The runaway process, encapsulated by Ronald Fisher’s sexy sons hypothesis, occurs when females mate with males possessing desirable traits. These traits are inherited by their sons, increasing the likelihood that future generations of females will mate with them, thus perpetuating the traits.
What did David Buss (1989) find in his cross-cultural study on partner preferences?
David Buss found that females valued resource-related characteristics like good financial prospects and ambition, while males valued reproductive capacity, such as good looks and youth. These findings reflect sex differences in mate strategies due to anisogamy and support sexual selection theory.
What did Clark and Hatfield (1989) demonstrate about female choosiness?
Clark and Hatfield found that no female students agreed to a request for casual sex, while 75% of males did. This supports the idea that females are choosier than males in selecting sexual partners, aligning with evolutionary predictions.
How do social and cultural influences affect partner preferences?
Social and cultural changes, such as women’s increased role in the workplace and availability of contraception, have influenced partner preferences. These changes occur faster than evolutionary timescales, leading to shifts in mate preferences that may no longer align with traditional evolutionary predictions.
What did Singh (1993, 2002) find about waist-hip ratio (WHR) and male preferences?
Singh found that males prefer a waist-hip ratio of about 0.7, as it signals fertility and non-pregnancy. This preference is consistent across cultures and supports evolutionary predictions about male partner preferences.
What did Waynforth and Dunbar (1995) find in their study of lonely hearts advertisements?
Waynforth and Dunbar found that women tended to offer physical attractiveness and youth, while men offered resources and sought youth and physical attractiveness. These findings support predictions from sexual selection theory about sex differences in mate preferences.
What did Singh (1993, 2002) find about waist-hip ratio (WHR) and male preferences?
Singh found that males prefer a waist-hip ratio of about 0.7, as it signals fertility and non-pregnancy. This preference is consistent across cultures and supports evolutionary predictions about male partner preferences.
What did Waynforth and Dunbar (1995) find in their study of lonely hearts advertisements?
Waynforth and Dunbar found that women tended to offer physical attractiveness and youth, while men offered resources and sought youth and physical attractiveness. These findings support predictions from sexual selection theory about sex differences in mate preferences.
