What is the effect of strong selection combined with low migration on a population?

The effect of strong selection combined with low migration leads to significant differentiation of a population from others, facilitating local adaptation. When strong selection pressures, such as those arising from environmental factors or resource competition, act on a population, they favor individuals with traits well-suited to their specific environment. This selection process enhances the traits that contribute to survival and reproduction in that particular ecological context.

Low migration means that fewer individuals from other populations can interbreed with this selected population. As a result, the genes that provide an adaptive advantage are more likely to become fixed within the population due to the lack of incoming genetic variability that could counteract the local adaptations. Consequently, over time, the genetic divergence between this population and others increases. Local adaptation helps the population become better suited to its environment, while also reducing gene flow with neighboring populations, reinforcing the divergence process.

This scenario emphasizes the dynamic interplay between natural selection and gene flow in evolutionary processes. The outcome is a distinct, locally adapted population that may evolve traits specifically suited to its unique circumstances.