Data from: 50 years of inordinate fondness

When theologians inquired whether anything could be concluded about the
creator from studying the creation, evolutionary biologist J.B.S. Haldane
allegedly replied “an inordinate fondness for beetles”, as there are more
kinds of beetles than any other insect. We may similarly conclude that the
creator is not particularly fond of the two species of colugos (that 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 hundred
hawks and eagles (Sibley and Ahlquist 1990; Sibley and Monroe 1990)⁠. Of
course, few evolutionary biologists would endorse the view that numbers of
species reflect 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: (i)
random chance, (ii) ecological opportunity, and (iii) key adaptations 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.