Sexual selection

Definition

Sexual selection is a form of natural selection where certain traits increase an individual's chances of attracting mates and reproducing. This concept helps explain the evolution of various traits that may not necessarily enhance survival but improve mating success, like elaborate plumage or vocal displays. It highlights the dynamic interplay between mate choice and competition, leading to diverse reproductive strategies and behaviors in different species.

5 Must Know Facts For Your Next Test

1. Sexual selection can lead to the development of secondary sexual characteristics, such as peacock tails or antlers in deer, which may hinder survival but enhance mating success.
2. Mate choice often involves female preference for males with specific traits, which can drive the evolution of those traits through selective pressures.
3. In some species, males will engage in elaborate displays or competitive behaviors to attract females, showcasing their strength or genetic fitness.
4. Sperm competition occurs when the sperm from multiple males compete to fertilize a female's eggs, leading to evolutionary adaptations in sperm size, quantity, and quality.
5. Cryptic female choice refers to females having mechanisms that allow them to influence which male's sperm successfully fertilizes their eggs after mating has occurred.

Review Questions

• How does sexual selection differ from natural selection, and what are some implications for animal behavior?
  • Sexual selection is specifically focused on traits that affect mating success rather than survival. While natural selection favors traits that help an individual survive and thrive in its environment, sexual selection may promote traits that are beneficial for attracting mates even if they pose risks. This distinction leads to behaviors and characteristics in animals that prioritize reproductive success over other survival aspects, illustrating the complex dynamics of evolutionary pressures.
• What role do sensory integration and multimodal communication play in sexual selection across different species?
  • Sensory integration and multimodal communication significantly enhance sexual selection by allowing individuals to utilize multiple senses when assessing potential mates. For instance, animals may combine visual displays, auditory signals, and chemical cues to communicate fitness levels effectively. This interplay increases the likelihood of mate choice being influenced by comprehensive assessments rather than relying on a single signal type, which can lead to more informed decisions about reproductive partners.
• Evaluate how parental investment strategies interact with sexual selection mechanisms in shaping mating systems among species.
  • Parental investment strategies directly influence sexual selection mechanisms by determining how much time and energy each sex allocates to offspring care versus seeking additional mating opportunities. In species where one sex invests heavily in parental care, such as birds where females incubate eggs, the other sex often competes for mating opportunities through displays or aggressive interactions. This dynamic shapes mating systems like monogamy or polygyny, as the balance of investment and competition can lead to differing reproductive strategies that maximize fitness for both sexes.

Related terms

Mate choice: The process by which one sex selects a partner based on specific traits or behaviors, influencing the genetic diversity and fitness of offspring.

Intrasexual competition: A form of competition where individuals of the same sex compete for access to mates, often resulting in the evolution of traits that help one individual outcompete another.

Sexual dimorphism: The differences in appearance or behavior between males and females of the same species, often as a result of sexual selection.