Happy Birthday Charles Darwin

and Abraham Lincoln too. Not to disrespect Lincoln, it's just that I can't offhand think of an information graphic hook to hang his birthday on. Darwin has this:



The tree format can't have been new; it's inherent in the Linnaean classification system (although the tree diagram's logical equivalent, the system of nested boxes, is probably closer to the original thought there) but the picture from Darwin's notebooks is a fascinating snapshot of a mind groping toward a mechanism for the descent of species from species. And the resemblance to a family tree can't have been lost on a scion of the famous Darwin-Wedgewoods.