Jerry Coyne has a guest post by Andrew Berry recognizing the history of Alfred Russel Wallace, co-innovator of the concept of natural selection: "A guest post for Wallace Day".
The reasons for Wallace’s relative obscurity are many and complex but it’s worth noting two things. It started early: his eclipse by Darwin is not solely a function of hindsight’s preference for one over the other. During the years after the publication of On the Origin of Species, when Darwin was at the height of his powers and Wallace was scientifically at his most productive, it was Darwin, and Darwin alone, who was co-identified in the public eye with the theory of evolution. A survey of contemporary cartoons and caricatures lampooning the idea reveals a plethora of Darwin-themed (or Darwin-apeing) images, and none—zero—that feature Wallace.
Second, Wallace himself was partially responsible for this. His wonderful account of his 8 years in Southeast Asia, The Malay Archipelago, which recounts what he did and what he saw in some considerable detail (a contemporary review in The Atlantic Monthly put it a little unkindly, “Mr. Wallace apparently exhausts a very copious diary in the production of his book, and seems almost to have made it a point of conscience not to leave anything out”), does not mention, even in passing, the events surrounding his evolutionary discoveries. In The Malay Archipelago Wallace refers repeatedly to the idea of natural selection, but always calls it “Mr. Darwin’s theory”. There is something pathologically modest about Wallace.
Anthropologists often note the importance of Wallace. During the decade following Darwin's publication of the Origin, Darwin himself was publicly silent about the implications of his theory for understanding humans. During this time, Wallace took the fore, delivering public lectures and publishing on the importance of natural selection as applied to people. Wallace unfortunately disagreed strongly with Darwin's perspective on human evolution. Wallace argued that natural selection had ceased affecting humans in any important way very long ago, and that the divergence of the present races of humans must go very far back in time -- as far as the Eocene. This was not an outlandish view relative to the physical anthropologists of the day. But it laid the groundwork for a scientific polygenism -- the idea that human races have long separate origins. Darwin by contrast was a fervent monogenist, and believed that natural selection has been operating in the recent past to generate human differences.
Wallace would soften to some extent in his interpretation of human evolution, but retained throughout his life a conviction that natural selection by itself was not sufficient to explain many of the qualities of humans today.