Whose work revolutionized the study of biology and ethology?

The work of Charles Darwin revolutionized the study of biology and ethology through his theory of evolution by natural selection. His groundbreaking publication, "On the Origin of Species," introduced the idea that species evolve over time through a process where individuals with advantageous traits are more likely to survive and reproduce. This concept fundamentally changed how scientists understand the development and adaptation of species in the natural world.

Darwin's ideas not only provided a unifying framework for the biological sciences but also laid the groundwork for the emerging field of ethology, which studies animal behavior. By demonstrating how behaviors could be influenced by evolutionary pressures, Darwin’s work connected biology and the observation of behavior in living organisms, leading to a deeper comprehension of the natural instincts and social structures that animals demonstrate.

Mendel's work focused on inheritance and genetics, which has influenced biology significantly but does not encompass the broader implications of evolutionary theory. Pasteur made critical contributions to microbiology and the germ theory of disease, while Einstein is known for his contributions to physics rather than biology. Thus, Darwin’s insights are foundational in the study of both biology and ethology.