Final answer:
Comte de Buffon was significant in evolutionary thought as he suggested species change over time and that Earth is older than believed, influencing future theories of evolution and natural selection.
Step-by-step explanation:
Comte de Buffon was important in the development of evolutionary thought because he proposed that species changed over time and that the Earth was much older than previously believed (option D). During the 18th century, Buffon reintroduced ideas on animal evolution and suggested that geographical regions have distinct plant and animal populations, contributing to the foundation upon which later scientists like Charles Darwin would build. Buffon challenged the then-accepted age of the Earth, around 6,000 years, arguing for a much longer historical timeline that would allow for the gradual changes in species that he and others observed.
Buffon's considerations on species diversity and Earth's age harmonized with geological theories proposed by James Hutton and later popularized by Charles Lyell. These geological insights provided a broader temporal context in which biological evolution could plausibly occur, thus setting the stage for Darwin and others to develop the theory of natural selection.