Alfred Wallace ... has a stronger claim to the theory of evolution by natural selection than has Darwin. In 1855, Wallace's first paper on evolution prompted Charles Lyell to warn Darwin that Wallace seemed close to solving the "species problem" and to urge him to publish his own theory.Jerry Coyne tells of a new paper that says Darwin did not get the Wallace letter until June 18, but the letter has been lost and we do not know for sure what it said.
Three years later, while studying the fauna of the Malayan archipelago, Wallace completed his theory and sent it to Darwin from the island of Ternate on 9 March 1858. Sent to England on the same boat was a letter to Frederick Bates, who received it on 3 June. It seems that Darwin wrote to Joseph Hooker on 8 June, saying he had found the "missing keystone" that enabled the completion of his evolution theory, while on 18 June, he wrote that he had just received a letter from Wallace proposing a theory of evolution identical to his own – a very suspicious chronology! Although it initially became known as the Darwin-Wallace theory, Darwin took the glory and Wallace was largely forgotten. Lacking Darwin's establishment connections, Wallace was shabbily treated and should be recognised as at least an equal in the Wallace-Darwin theory of evolution.
This is the wrong dispute. Natural selection was not a new idea. Credit should go for new ideas, or showing that some idea is measurably better than some competing idea. Darwin collected a lot of good observations and arguments, but natural selection and "survival of the fittest" were more slogans than science.