Sexual Selection

Sexual selection is a mechanism in evolution that drives the development of certain traits or behaviors in order to increase an organism’s chances of mating and reproducing successfully.


Natural selection favors traits that enhance an organism’s survival and ability to adapt to its environment. However, sexual selection specifically acts on traits that increase an organism’s attractiveness to potential mates.

Types of Sexual Selection

Sexual selection can be divided into two main types:

  1. Intrasexual selection: This form of sexual selection involves competition between members of the same sex for access to mates. It often results in the evolution of traits that improve competitive abilities, such as elaborate weaponry or displays.
  2. Intersexual selection: Intersexual selection occurs when individuals of one sex choose mates based on certain preferred traits. This type of selection can lead to the development of traits that are attractive to the opposite sex, such as bright colors, extravagant plumage, or elaborate courtship behaviors.

Factors Influencing Sexual Selection

Several factors can influence sexual selection:

  • Competition: Intense competition between individuals of the same sex can lead to the evolution of traits or behaviors that increase chances of winning competitions and gaining access to mates.
  • Female choice: Females often have the final say in selecting a mate. They may choose males with specific traits that indicate good genetic quality, health, or have the ability to provide resources for offspring.
  • Male-male competition: Males may compete with each other directly to gain the attention or favor of females. This competition can take various forms, including physical contests or displaying elaborate courtship rituals.

Impact on Evolution

Sexual selection can have significant impacts on the evolution of species:

  • It can lead to the development of exaggerated traits that may, at times, seem impractical or even detrimental to survival. These traits are often indicators of the individual’s fitness and can attract potential mates.
  • Sexual selection can create sexual dimorphism, where males and females of a species exhibit distinct physical or behavioral differences.
  • It can drive rapid evolutionary changes in certain populations, as the competition for mates puts selective pressure on specific traits.


Sexual selection is a crucial evolutionary process that helps shape the diversity of life on Earth. By favoring traits that enhance reproductive success, sexual selection plays a significant role in the evolution of organisms, their behaviors, and their adaptations.