Darwin's original thesis, and the viewpoint supported by evolutionary gradualists, is that species change continuously but slowly and in small increments.
达尔文最初的论点以及进化渐进主义者所支持的观点是，物种的变化是持续的，但非常缓慢，增量也很小。
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Surveyors marched inland from the coast for thousands of miles, stopping at increments of as little as a few feet to measure their elevation, and marking each increment with two poles.