Sexual selection

Definition

Sexual selection is a form of natural selection where individuals with certain traits are more likely to attract mates and reproduce. This process can lead to the evolution of traits that may seem disadvantageous for survival but enhance reproductive success, such as elaborate plumage in birds or displays of strength. Understanding sexual selection sheds light on the complexities of reproductive behaviors and social dynamics in various species.

5 Must Know Facts For Your Next Test

1. Sexual selection can result in traits that are not necessarily advantageous for survival, such as peacock feathers that attract predators but help attract mates.
2. Mate choice can be influenced by factors like symmetry, coloration, and behavioral displays, which signal health and genetic fitness.
3. Intrasexual competition often leads to the evolution of pronounced physical traits in males, like larger antlers in deer, to outcompete rivals.
4. Sexual dimorphism often manifests in size, coloration, and ornamentation, showcasing how males and females adapt differently through sexual selection.
5. Sexual selection can drive evolutionary change rapidly compared to natural selection due to the strong pressures associated with mating success.

Review Questions

• How does sexual selection differ from natural selection in terms of its impact on reproductive strategies?
  • Sexual selection differs from natural selection in that it specifically focuses on traits that enhance an individual's chances of attracting a mate rather than solely on survival. While natural selection promotes adaptations that improve overall fitness in an environment, sexual selection encourages the development of characteristics that may be extravagant or risky but boost reproductive success. For instance, a brightly colored male might attract more females despite being more visible to predators.
• What role does mate choice play in the process of sexual selection and its effects on evolutionary outcomes?
  • Mate choice is central to sexual selection as it allows individuals to select partners based on desirable traits that indicate genetic fitness or health. This selective pressure influences which traits become more pronounced over generations, leading to evolutionary changes within a population. For example, if females consistently choose mates with vibrant coloration, this trait becomes more prevalent in subsequent generations, showcasing how mate choice directly shapes evolutionary pathways.
• Evaluate the consequences of sexual dimorphism on social behaviors and mating systems across different species.
  • Sexual dimorphism can significantly affect social behaviors and mating systems by establishing distinct roles for males and females within a species. In many cases, pronounced differences lead to complex mating strategies, such as polygyny or monogamy. For example, in species where males are larger and more ornamented, their competitive behaviors may drive males to engage in fights or displays to win female attention. Conversely, females may be more selective, leading to variations in parental investment and social structures that ultimately shape how species interact with one another within their ecosystems.

Related terms

mate choice: The process by which an individual selects a partner based on certain desirable traits, influencing the genetic diversity and fitness of future generations.

intrasexual competition: A form of sexual selection where members of one sex compete with each other for access to mates, often leading to the development of traits like larger size or weaponry.

sexual dimorphism: The differences in appearance and behavior between males and females of the same species, often resulting from sexual selection processes.