Knowra Gradualism Gradualism Gradualism is the view that major geological and biological changes generally accumulate through slow, continuous processes rather than sudden transformations.
Deep time : The immense span of geological time, extending across billions of years of Earth history. Long durations let rates too slow to notice produce large geological effects.
James Hutton : A Scottish geologist whose work argued that Earth’s features reflect long-running natural processes. His account of a slowly changing Earth helped establish gradual geological explanation.
Catastrophism : The view that major geological features and changes result chiefly from sudden, large-scale events. It emphasizes abrupt events where gradualism emphasizes cumulative processes.
Stratigraphy : The study of rock layers and their sequence, distribution, and relationships. Layered rocks help reconstruct histories assembled through successive geological events.
Rate of evolution : The speed at which heritable characteristics change in populations over time. Evolutionary rates vary, raising questions about when gradual models fit best.
Erosion : The wearing away and transport of rock or soil by water, wind, ice, or gravity. Persistent erosion slowly reshapes landscapes without requiring a single catastrophic event.
Charles Lyell : A nineteenth-century geologist who argued that present-day geological processes explain Earth’s past. His geological arguments made gradual change influential in Darwin’s intellectual environment.
Punctuated equilibrium : An evolutionary model in which species show long periods of relative stability interrupted by comparatively rapid change. It challenges the expectation that evolutionary change proceeds at a steady, visible pace.
Geological time scale : A system that divides Earth’s history into chronologically ordered eons, eras, periods, and epochs. It gives gradual geological change the vast timescale needed to accumulate.
Mass extinction : An interval in which an unusually large proportion of Earth’s species becomes extinct worldwide. These abrupt losses test accounts that emphasize slow, continuous biological change.
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