The Origin of Species

“blogging the origin” criticizes Darwin for emphasizing selection, rather than separation, as the primary cause of speciation. But we now know that Darwin was, as usual, right, and the latest fashions were, as usual, wrong again.

Until recently the evidence for *any* speciation was thin, and in the absence of evidence, people liked to imagine speciation by physical separation, in large part due the rhetoric of Gould, who argued that absence of evidence was evidence for presence of the events he wished were happening.

The research on three spined sticklebacks, shows that for three spined sticklebacks, sympatric speciation is extremely common, and allopatric speciation is insignificant in the sense that: if two physically separated groups of three spined sticklebacks adapt to similar environments, they become similar, and can and will interbreed if given the opportunity, but if they adapt to different environments, then, whether separated or not, they become different, and disinclined to interbreed if given the opportunity.

Science. 2000 Jan 14;287(5451):306-8

“Populations of sticklebacks that evolved under different ecological conditions show strong reproductive isolation, whereas populations that evolved independently under similar ecological conditions lack isolation.”

Which implies that:  separation and drift does not matter in speciation, does not cause speciation; Differential adaption matters, does cause speciation, as Darwin argued.

Our most complete record on speciation events is that for foraminifera, because we have a humungous number of fossils neatly stacked in layers at the sea bottom.
For foraminifera, all observed speciation events that have been observed in sufficient detail are sympatric.

Gould wanted to discredit sympatric speciation, and argued for the primacy of allopatric speciation, because if adaption, rather than separation, is primary, then this has disturbing implications for our own species. From the supposed primacy of separation over adaption, Gould argued in his essay “human equality is a contingent fact of history” that the races of man must be equal in mean and distribution of abilities, thus the primacy of adaptive speciation over allopatric speciation that we do in fact observe today is as disturbingly politically incorrect as Darwin’s comments on the races of man.

If it is possible for sticklebacks that share a single lake to divide into two species, despite substantial interbreeding, then it is probable that humans whose ancestors lived for the last fifty thousand years or so in an environment where lack of future orientation would result in freezing in bad weather and starving in winter, have considerably greater future orientation than humans whos ancestors lived in an environment where failure to prepare for the future was considerably less likely to be lethal.