Who is primarily known for independently developing a theory of natural selection similar to Darwin's?

Alfred Wallace is primarily known for independently developing a theory of natural selection that is remarkably similar to Charles Darwin's. Wallace's work involved extensive field studies and observations of species in the Malay Archipelago, leading him to formulate his ideas about natural selection around the same time as Darwin was developing his own theory. In fact, Wallace's paper on the subject prompted Darwin to present his findings to the scientific community. Their ideas shared key principles about how species evolve through the process of natural selection acting on variations within populations.

The contributions of figures such as Gregor Mendel and James Watson are vital in the broader field of genetics but do not relate specifically to the theory of natural selection. Stanley Miller is best known for his experiments that investigated the origin of life, rather than evolutionary theory itself. Wallace's contributions solidify his role as a co-founder of the theory of evolution by natural selection alongside Darwin, making him a pivotal figure in the history of biology.