Which theory supports the notion that environmental changes drive gradual evolution?

Gradualism is the theory that proposes that evolution occurs slowly and steadily through small, incremental changes over long periods of time, driven by environmental changes. This concept suggests that adaptations arise as organisms gradually respond to fluctuating environmental conditions, leading to the development of new species through a continuous and uniform process.

The idea of gradualism emphasizes the importance of time and environmental pressures in shaping the evolution of species. By accumulating small variations over countless generations, populations can slowly diverge from their ancestral forms, leading to speciation. This theory aligns with observable evidence in the fossil record, where transitional forms demonstrate the gradual changes in species.

In contrast to gradualism, other theories like mutation theory focus on sudden genetic changes, and reproductive isolation theory addresses the mechanisms by which species remain distinct once they have diverged. The extraterrestrial impact theory suggests radical shifts in evolution due to external catastrophic events, which is not compatible with the gradual shifts proposed by gradualism.