Recall how Alfred Russel Wallace's theory compared to Darwin's theory of evolution by natural selection.

If people were to be asked who developed the natural selection theory, almost always, Charles Darwin would be the name associated with it. But, Alfred Wallace is also the co-author or co-discoverer of the theory of evolution by natural selection. He was a naturalist that collected several species of plants and animals for experimental purposes. Both men actually published a joint paper arguing the theory of evolution and natural selection. But eventually Wallace faded when Darwin wrote the book the Origin of the Species.