Final answer:
Charles Lyell was a pivotal figure in geology, who proposed the theory of uniformitarianism and influenced Charles Darwin's work on evolution by suggesting a much older Earth than previously thought.
Step-by-step explanation:
Scottish geologist Charles Lyell, known as the father of modern geology, significantly contributed to evolutionary thinking with his work Principles of Geology. Lyell championed the theory of uniformitarianism, suggesting that the geological processes shaping the Earth today have been the same throughout Earth's history. This principle indicates that the Earth must be far older than the then-widely accepted few thousand years, altering the perceived timeframe necessary for significant geological and biological changes to take place. Lyell's concepts were essential for Charles Darwin, as they provided the understanding of an Earth old enough for the gradual evolution of species through natural selection.
In Principles of Geology, Lyell stated that landscapes such as mountains, lakes, and rivers were all created by slow-moving geological processes like wind and rain. His arguments for a much older Earth and the ongoing nature of geological change directly influenced Darwin's development of the theory of evolution by natural selection, giving scientific credence to the idea of extended periods for the evolution of life on Earth.
By promoting the idea of a much older Earth and refuting the belief in a young Earth based on Biblical chronology, Lyell's work laid the groundwork for modern geology and evolutionary biology, impacting scientific thought profoundly.