What was Thomas Malthus known for?

Thomas Malthus is primarily known for his contributions as a biologist and political economist, particularly for his theories regarding population growth and its implications for resources and society. In his influential work "An Essay on the Principle of Population," Malthus argued that population tends to increase exponentially while food production increases arithmetically, leading to a point where resources could become insufficient to support the population. This concept has had a lasting impact on discussions around economics, population dynamics, and environmental sustainability.

The other options do not accurately represent Malthus's contributions. He was not recognized as a famous author or poet, nor is he associated with ancient Greek philosophy. While he may have had influences on environmental science, his foundational work was primarily situated in political economy and demographics rather than being a historical figure explicitly labeled in the field of environmental science.