What concept refers to slow, gradual changes in species over time?

The concept that refers to slow, gradual changes in species over time is called gradualism. This theory posits that evolutionary changes occur steadily and continuously, reflecting the cumulative effects of small genetic variations and environmental factors over long periods. It suggests that new species arise as a result of these incremental changes rather than through sudden, dramatic transformations.

Gradualism contrasts with punctuated equilibrium, which proposes that species remain relatively stable for long periods, interrupted by short bursts of rapid evolution. Adaptive radiation refers to the process where a single ancestral species diversifies into a variety of forms to exploit different ecological niches. Convergent evolution describes a scenario where unrelated organisms develop similar traits or adaptations due to analogous environmental pressures, rather than a shared ancestry. These distinctions highlight why gradualism specifically emphasizes the slow, steady evolutionary change over time.