by Greg Mayer
Created by Mike Rosulek, he is selling t-shirts and posters of this, and several other designs, with proceeds to benefit the National Center for Science Education, a most worthy recipient. I might quibble with “very gradual”, which might evoke memories of the old punctuated equilibrium debate. Darwin was certainly a gradualist, but as understood by Darwin, and succunctly characterized in chapter 1 of WEIT, gradualism is not incompatible with highly varying rates of change across time and among lineages. The best summary of Darwin’s views on the subject is a paper by Frank Rhodes entitled ‘Gradualism, punctuated equilibrium and the Origin of Species‘ published in Nature (305:269-272) in 1983.
(hat tip: Andrew Sullivan)