Sexual Selection Shapes Reproductive Success
- Traits that improve mating success, rather than survival, are shaped by sexual selection.
- These traits, such as vibrant feathers or elaborate dances, evolve because they enhance the likelihood of attracting a mate.
Sexual Selection Focuses on Mating, Not Survival
- Sexual selection is a type of natural selection, but its focus is different:
- Natural selection favors traits that improve survival.
- Sexual selection favors traits that increase reproductive success, even if they reduce survival chances.
Two Pathways of Sexual Selection
1. Mate Choice (Intersexual Selection)
- One sex (often females) chooses mates based on traits signaling health or genetic fitness.
Female guppies prefer males with brighter coloration, associating it with good health.
2. Competition for Mates (Intrasexual Selection)
- Individuals of the same sex (usually males) compete for access to mates.
- This can involve physical contests or visual displays of dominance.
Stags use their antlers in battles to win access to females
Why Females Are Picky About Mates
- In many species, females invest more resources in reproduction (e.g., producing eggs, gestation, or raising offspring).
- This makes them selective, choosing mates that maximize the survival and fitness of their offspring.
Male traits, like bright colors or elaborate displays, may increase predator attention but are favored because they boost mating success.
Examples of Sexual Selection in Action
Birds of Paradise: Dancing for Attention
- Male birds of paradise are famous for their extravagant plumage and courtship dances.
