EVOLUTIONARILY STABLE STRATEGY Meaning and
Definition
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Evolutionarily Stable Strategy (ESS) is a concept in game theory and evolutionary biology that refers to a behavioral strategy that, once established in a population, resists invasion by any other alternative strategies. An ESS represents an equilibrium point in a population where individuals' behaviors maximize their fitness, in the sense that it allows them to leave the highest number of viable offspring.
To be considered an ESS, a strategy should satisfy two essential conditions. Firstly, when implemented by a significant proportion of the population, the strategy should fare better in terms of fitness compared to alternative strategies. This ensures that individuals adopting the ESS will pass down their genetic material to subsequent generations more effectively. Secondly, the ESS should be resistant to invasion by mutation or the introduction of alternative strategies. This implies that individuals adopting other strategies should not be able to invade and displace those using the ESS.
An ESS is a dynamic equilibrium, meaning that it can evolve and change over time due to environmental or population conditions. However, these fluctuations typically only result in minor adjustments to the ESS, rather than a complete replacement.
The concept of an ESS is essential in explaining the evolution of various traits observed in nature, such as fighting behavior among animals, mating strategies, foraging tactics, and territoriality. Overall, the ESS concept provides a framework for understanding how natural selection shapes the behavior of individuals within a population in order to optimize their reproductive success and survival.
