What effect does gene flow generally have on populations?

Gene flow generally has the effect of increasing genetic diversity within a population. This occurs because gene flow involves the transfer of genetic material between populations, typically through the movement of individuals or their gametes. When individuals from different populations interbreed, they introduce new alleles into the gene pool, which enhances genetic variability. This influx of new genetic material can provide a broader range of traits upon which natural selection can act, potentially leading to more adaptive responses to environmental changes.

Additionally, increased genetic diversity can enhance a population's resilience to diseases and environmental stresses, making it better equipped for survival over time. Hence, the correct understanding emphasizes that gene flow serves as a mechanism for enhancing the genetic diversity of populations, fundamentally contributing to evolutionary processes.