Final answer:
Charles Lyell, the father of modern geology, influenced the understanding of Earth's age and geological processes with his work on uniformitarianism, contributing to the foundation for evolutionary theory.
Step-by-step explanation:
Scottish geologist Charles Lyell is a key figure in the field of geology and greatly influenced evolutionary thought. As the father of modern geology, Lyell wrote the seminal work Principles of Geology, arguing for the principle of uniformitarianism — the idea that the geological processes we observe today, such as erosion from wind and rain, were the same in the past. This principle, in turn, suggested that the Earth is much older than the few thousand years previously believed, providing a timescale that supports the gradual changes in species.
Lyell's concepts of an older Earth and continuous geological processes were important to the development of Charles Darwin's theory of evolution by natural selection. Darwin, a friend of Lyell, was influenced by the idea that Earth's age allowed ample time for the slow process of evolution to occur. Lyell's work helped forge the framework for understanding the Earth's geological past and the evolution of life.