Sexual Selection, Types of Selection, and Species Concepts

Sexual Selection Review and Types of Selection

Sexual Selection

• Definition: Selection caused by factors related to mating and behavior, generally observed in animals.

  • Contrast with Natural Selection: Natural selection is driven by the impact of the environment (biotic components like interactions between organisms, or abiotic factors like temperature) on survival and reproduction.

• Fundamental Asymmetry of Sex:

  • In most organisms, females invest more energy into producing gametes (eggs are costlier than sperm) and raising offspring.

  • Consequence: Males typically compete for access to female mates; females generally do not have to compete for access to mates.

• Types of Sexual Selection:

  • Intersexual Selection: Females choosing mates drives the evolution of male traits that make them more showy (e.g., elaborate displays, bright colors).

  • Intrasexual Selection: Competition between males (within one sex,