Donald Prothero: In evolution, stasis was general, gradualism rare, and that’s the consensus 40 years on
|February 15, 2012||Posted by News under Darwinism, stasis, News|
The “punctuated equilibrium” paper is a masterpiece of writing and incisive thinking, which poses a number of interesting issues. The first part is a general discourse on the philosophy of science, which argues that all scientists are products of their time and culture and tend to see what they expect to see. In this context, Darwin led paleontologists to expect phyletic gradualism, which they vainly tried to document for over a century before the allopatric speciation model came along.
It’s not clear that abundant evidence followed the model – more like a few aha! moments in the general bleakness.
For the first decade after the paper was published, it was the most controversial and hotly argued idea in all of paleontology. Soon the great debate among paleontologists boiled down to just a few central points, which Gould and Eldredge (1977) nicely summarized on the fifth anniversary of the paper’s release. The first major discovery was that stasis was much more prevalent in the fossil record than had been previously supposed. Many paleontologists came forward and pointed out that the geological literature was one vast monument to stasis, with relatively few cases where anyone had observed gradual evolution. If species didn’t appear suddenly in the fossil record and remain relatively unchanged, then biostratigraphy would never work—and yet almost two centuries of successful biostratigraphic correlations was evidence of just this kind of pattern. As Gould put it, it was the “dirty little secret” hidden in the paleontological closet. Most paleontologists were trained to focus on gradual evolution as the only pattern of interest, and ignored stasis as “not evolutionary change” and therefore uninteresting, to be overlooked or minimized. Once Eldredge and Gould had pointed out that stasis was equally important (“stasis is data” in Gould’s words), paleontologists all over the world saw that stasis was the general pattern, and that gradualism was rare—and that is still the consensus 40 years later. – “Darwin’s Legacy,”eSkeptic , February 15, 2012 (scroll down)
If stasis is the general pattern, why do we hear so little about it?
For that matter, if “stasis was the general pattern, and that gradualism was rare—and that is still the consensus 40 years later” why does the Darwin lobby oppose allowing students to learn about stasis?
Better still, reflecting on some of his own work, Prothero tells us,
In four of the biggest climatic-vegetational events of the last 50 million years, the mammals and birds show no noticeable change in response to changing climates. No matter how many presentations I give where I show these data, no one (including myself) has a good explanation yet for such widespread stasis despite the obvious selective pressures of changing climate. Rather than answers, we have more questions—and that’s a good thing! Science advances when we discover what we don’t know, or we discover that simple answers we’d been following for years no longer work.
Is that really how science advances? Good to know. To judge from typical evolutionary biologists of Prothero’s vintage, their form of science supposedly advanced by closing ranks and spouting Darwinian gradualism at the public – even though they knew it wasn’t true.
And then wittering to the world that people didn’t believe them, when they didn’t even believe themselves.
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