Sexual selection

Definition

Sexual selection is a mode of natural selection where individuals with certain inherited traits are more likely than others to obtain mates. This process can lead to the evolution of traits that improve mating success, even if they may not necessarily benefit survival. In the context of human origins, sexual selection plays a significant role in shaping behaviors, physical characteristics, and social structures that have influenced human evolution.

5 Must Know Facts For Your Next Test

1. Charles Darwin first introduced the concept of sexual selection in his work 'The Descent of Man', arguing that certain traits evolve not just for survival but to attract mates.
2. Sexual selection can lead to the development of exaggerated traits, such as peacock feathers or antlers in deer, which may increase visibility to predators but also enhance mating opportunities.
3. In humans, factors influenced by sexual selection include physical attractiveness, social status, and intelligence, all of which can affect mate choice.
4. Sexual selection can create strong pressures on population dynamics, affecting genetic diversity and influencing evolutionary pathways.
5. The effects of sexual selection are observable in both physical traits (like body size) and behavioral traits (like courtship rituals) across different cultures and societies.

Review Questions

• How does sexual selection differ from natural selection in terms of evolutionary outcomes?
  • Sexual selection differs from natural selection primarily in its focus on traits related to mating success rather than survival. While natural selection emphasizes adaptations that enhance survival in a given environment, sexual selection drives the evolution of features that improve an individual's chances of attracting a mate. This means that some traits may evolve even if they pose risks to survival, as their reproductive benefits outweigh potential downsides.
• Discuss the implications of sexual dimorphism in human origins and how it relates to sexual selection.
  • Sexual dimorphism in humans illustrates how sexual selection has influenced our species' evolution. Observable differences between males and females, such as body size and physical features, often arise from selective pressures related to mate choice and competition. These differences provide insights into past mating strategies and social structures that likely played roles in shaping human behavior and societal roles throughout history.
• Evaluate the role of cultural factors in shaping sexual selection among humans and their evolutionary consequences.
  • Cultural factors significantly shape sexual selection by influencing preferences for certain traits or behaviors within mate choice. For example, cultural norms around beauty standards can affect which individuals are considered desirable partners, ultimately influencing reproductive success and gene flow within populations. This interplay between culture and biological evolution leads to diverse expressions of sexuality and mating practices across different societies, highlighting how cultural evolution can drive changes in human evolutionary trajectories.

Related terms

Mate choice: The process by which an individual selects a partner based on specific traits or characteristics, often linked to perceived genetic quality or fitness.

Intrasexual competition: A form of sexual selection where members of the same sex compete for access to mates, often resulting in the evolution of physical or behavioral traits that enhance competitive success.

Sexual dimorphism: The differences in size, shape, or coloration between males and females of the same species, often a result of sexual selection pressures.