50 Years of Inordinate Fondness

摘要

When theologians inquired whether anything could be concluded about the creator from studying the creation, evolutionary biologist J.B.S. Haldane allegedly replied that the creator must have “an inordinate fondness for beetles”, as there are more kinds of beetles than any other insect. One might similarly conclude that the creator is not particularly fond of the two species of colugo, which are sister to more than 350 primate species (Bininda-Emonds et al. 2007), or the osprey, which is the single sister species to more than a 100 hawks and eagles (Sibley and Ahlquist 1990; Sibley and Monroe 1990). Of course, few evolutionary biologists would endorse the view that numbers of species re?ect the interest of a divine creator, but there is no consensus on an alternative explanation. We can distinguish three broad categories of explanations for distributions of species over taxa: (1) random chance, (2) ecological opportunity, and (3) key innovations of species. All three explanations have garnered substantial support, but none accurately explains distributions of species over taxa by itself. Here we explain how these different explanations can be conceptually combined in a theory that yields accurate predictions of distributions of species over taxa.