Differences between Gradualism and Uniformitarianism

Question

From what I understand, gradualism is the idea that small changes affect species over time. Uniformitarianism argues that the same processes that occurred in the past are the same as those in the present.

Does gradualism state that these small changes are constant over time? In that case, it isn't much different from uniformitarianism.

I'm thinking that the difference that uniformitarianism allows for catastrophes and supports Aristotle's scala naturae, while gradualism makes a point for evolution due to its theory of slow processes.

Answer 1

Gradualism is the view that large-scale changes occurs by the accumulated effects of small changes over long periods of time, rather than by rare cataclysmic events of massive effect.

Uniformitarianism is the view that the same forces that shaped the world in the past continue to operate today. Historically, uniformitarianism has often included aspects of gradualism (i.e. definitions by Lyell), e.g. by assuming uniformity of rates. Uniformitarianism was also originally proposed as the opposite of Catastrophism. However, in modern use, the focus lies on uniformity of processes, and rapid catastrophic changes are allowed under uniformitarianism. Also note that the term Actualism is sometimes used for modern interpretations of uniformitarianism.

If we posited that early evolution occurred by small Lamarckian changes and current evolution occurs by small Darwinian changes, we have a model that is gradualist but not uniformitarian.

If we posited that the earth's topography was formed by meteor impacts and massive tsunamis, in sharp sudden strokes of massive effect, but acknowledged that these same processes occur today, we would have a theory that is uniformitarian but not gradualist.

(I don't understand what you are asking in your last paragraph, or how this relates to your main question.)