Final answer:
Uniformitarianism refers to the 17th and early 18th-century belief in a short geological history, which was challenged by James Hutton's proposal of long-term gradual geological changes and further popularized by Charles Lyell, influencing evolutionary theory.
Step-by-step explanation:
Uniformitarianism, a popular natural philosophy of the 17th and early 18th centuries, was based on a firm belief in a very short geologic history for Earth. This concept was challenged by Scottish geologist James Hutton who proposed that geological changes occurred gradually over long periods, which contrasted with the then-dominant belief in a young Earth shaped by catastrophic events. Hutton's ideas were further popularized by Charles Lyell, who supported the principle of uniformitarianism, suggesting that the Earth was much older than previously thought. Lyell's work had a significant influence on Charles Darwin and his development of evolutionary theory.