Scientist of the Day - Alfred Russel Wallace
Alfred Russel Wallace, a Welsh naturalist, died Nov. 7, 1913, at the age of 90. We wrote a post on Wallace almost 8 years ago, when this series was just getting started, and it was a decent post, but it was overly brief, as those early pieces tended to be. We did make the point that Wallace was the co-discoverer, with Charles Darwin, of evolution by natural selection, and that, unlike the well-heeled Darwin, he earned his living as a naturalist, selling exotica to dealers that in turn sold Wallace’s goods to stay-at-home collectors. Our post was illustrated with four lovely plates from Wallace's The Malay Archipelago (1869), a book almost as popular as Darwin's Voyage of the Beagle, as Darwin’s narrative would later be called. But we said nothing about the events of the 1850s, when Wallace inadvertently prodded Darwin into action, twice. The Origin of Species might not have been written at all, without the stimulus provided by Wallace. We are going to tell this story today, and on a later occasion, we will come back to look at Wallace the evolutionist of the 1860s and 1870s, since he went off in quite a different direction from Darwin, believing that natural selection could never account for the human species. We also need to say something about Wallace’s work in biogeography and his discovery of “Wallace’s line.”
Wallace entered Darwin’s world in 1855, when he published an article in the Annals and Magazine of Natural History. Wallace had been in Indonesia for two years (the beginning of an eight-year sojourn), and in his paper, he claimed to have discovered a fundamental law of nature, namely that "every species has come into existence coincident both in space and time with a closely allied species," in effect observing that there is a succession of types in the animal and plant world – that species are connected, chronologically and geographically.
Darwin read the article and realized that Wallace had observed what Darwin himself had first noticed in 1837, and he further understood that Wallace was close to stumbling on natural selection, which Darwin had been sitting on since 1838. With another runner now in the race, Darwin decided it was time to get his ideas into print, and he began work on a massive treatise on evolution by natural selection that we call “The Big Book,” since it was never published with a title of its own. Work proceeded slowly, because Darwin was being very thorough, and he had hardly gotten beyond the subject of artificial selection when he heard from Wallace again, on June 18, 1858.
This time Wallace wrote Darwin directly, and enclosed a manuscript he had written, asking Darwin if he approved of the argument, and if so, wondering if Darwin could forward it to a suitable journal for publication Darwin read the short article, called “On the Tendency of Varieties to depart indefinitely from the Original Type, ” and his heart must have sunk to the floor, for Wallace now had the whole enchilada, having come to exactly the same conclusions that Darwin had 14 years earlier, when he wrote down an outline of his theory of evolution by natural selection.