Frequency-dependent selection

Definition

Frequency-dependent selection is an evolutionary process where the fitness of a phenotype depends on its frequency relative to other phenotypes in a population. This type of selection can lead to diverse strategies in populations, as the success of one phenotype can change depending on how common or rare it is. As a result, this dynamic can drive the evolution of traits and behaviors in various species, often seen in population games where interactions between individuals play a crucial role.

5 Must Know Facts For Your Next Test

1. In frequency-dependent selection, rare phenotypes may have a fitness advantage over more common ones, encouraging diversity within the population.
2. The concept is closely tied to predator-prey dynamics, where predators may become more efficient at catching common prey types, favoring less common ones.
3. This selection mechanism is often illustrated through examples like mimicry, where less common mimics can thrive because they are not easily recognized by predators.
4. Frequency-dependent selection can contribute to the maintenance of genetic variation within populations, as different traits can become advantageous depending on their prevalence.
5. In population games, players might adapt their strategies based on the frequency of opponents' strategies, leading to shifts in behavior that reflect the competitive landscape.

Review Questions

• How does frequency-dependent selection influence the evolution of strategies in a population?
  • Frequency-dependent selection influences strategy evolution by changing the fitness outcomes for phenotypes based on their relative abundance. When a phenotype becomes too common, its fitness may decline as competitors adapt or predators become more efficient at targeting it. This dynamic encourages diversity as rare phenotypes gain an advantage, ensuring that no single strategy dominates the population for too long.
• Discuss the role of frequency-dependent selection in shaping genetic diversity within populations and provide an example.
  • Frequency-dependent selection plays a crucial role in maintaining genetic diversity within populations by allowing different traits to have varying fitness advantages based on their frequency. For example, in predator-prey interactions, if one prey type becomes very common, predators may learn to recognize it easily. As a result, less common prey types may survive better and proliferate, leading to a balance of traits and promoting overall genetic variation within the population.
• Evaluate the implications of frequency-dependent selection for modeling behaviors in strategic interactions using game theory.
  • Frequency-dependent selection significantly impacts game theory models by highlighting how players adjust their strategies based on the prevalence of others’ strategies. In scenarios where a particular strategy becomes dominant, players may shift to less common strategies to exploit the weaknesses associated with the popular choice. This constant adaptation creates a dynamic environment where optimal strategies are continuously evaluated and re-evaluated based on the ever-changing landscape of player interactions, ultimately shaping competitive behavior in various contexts.

Related terms

Evolutionary stable strategy (ESS): A strategy that, if adopted by a population, cannot be invaded by any alternative strategy because it yields the highest fitness when it is common.

Game theory: A mathematical framework for modeling situations in which players make decisions that affect each other's outcomes, often used to analyze strategic interactions among competing individuals.

Replicator dynamics: A mathematical model that describes how the frequency of strategies or traits changes over time in a population based on their relative payoffs.