IDiots Don't Understand Punctuated Equilibria

Intelligent Design Creationism is a movement dedicated to discrediting evolution and attacking the rational explanation of nature.¹ The evidence is in the books and blogs and the propaganda distributed to local school boards and state legislators. The attack on science and scientists makes up about 99% of their activities.

Given their dedication to disproving evolution, you'd think that the IDiots must at least understand it. Maybe not all of them—because there are some really, really, stupid IDiots—but certainly some of the most prominent IDiots should know what they're talking about? Right? Doesn't that seem reasonable?

The facts say otherwise. Off hand, I can't think of a single IDiot who has an adequate understanding of the science they attack. Believe me, I've tried harder than most to find an intelligent believer.

The latest example of an IDiot is Raymond (Ray) Bohlin [Encycleopedia of American Loons]. He has a Ph.D. in molecular cell biology from the University of Texas (Dallas). The post is on Evolution News & Views (sic) and it announces The Quiet Passing of Punctuated Equilibrium, Finally!.

Some of you may have forgotten about punctuated equilibria so let me give you a brief lesson. Punctuated equilibria refer to a general observation about the fossil record. In those cases where there's a continuous record for millions of years, the observation is that many species exist for millions of years without substantive change (stasis) then over a short period of time (thousands of years) new species form by cladogenesis (splitting of one species into two).

Most of the examples are small marine species, like trilobites, because those fossil records are extensive and well-documented. The speciation event involves small changes like those between modern species (i.e. different species of fruit flies or different species of pine trees). In fact, most of us wouldn't be able to tell the species apart if we looked at the fossils.

What we're seeing, according to Gould and Eldredge, is normal allopatric speciation in the fossil record. Here's Gould, writing in The Structure of Evolutionary Theory.

The theory asserts no novel claim about modes or mechanisms of speciation; punctuated equilibrium merely takes a standard microevolutionary model and elucidates its expected expression when properly scaled onto geological time. (p. 778)

This is important because many people—including, unfortunately, many scientists—have mistakenly assumed that punctuated equilibria have something to do with large-scale morphological changes (macromutation).

Gould, Eldredge, and others have written extensively about this confusion between punctuated equilibria and saltations. I think most scientists now realize that punctuated equilibria involve normal speciation events. It's correctly described in all the evolutionary biology textbooks.

This brings us to Ray Bohlin and his latest post. Here's what he says ...

From the beginning, punctuated equilibrium was primarily an observation from paleontology that most species seemed to stay the same over millions of years (stasis or equilibrium) and suddenly a new species appeared with no smooth transition (punctuation) from the previous species. Gould, Eldredge, and Stephen Stanley wrote numerous articles and books over twenty years summarizing and applying their ideas to different types of organisms in numerous geological time frames.

This was all fine and good as a paleontological observation, but how was this rapid punctuation supposed to happen biologically? Gould, in particular, was careful to point out that punctuated equilibrium was a descriptive theory of large-scale patterns over geological time, not a theory of genetic process. But if genetic process could not accomplish large-scale patterns, the observation becomes mute.

One of the candidates for explaining rapid change through speciation was some kind of developmental change. At the time it was called a bifurcation. A bifurcation is defined as a series of small changes that suddenly reveals a major shift. A child’s metal cricket or frog is a good example. These toys consist of a short piece of metal, grounded at one end. As the opposite end is bent, it eventually buckles emitting the desired “click.” So perhaps with populations, mutations in a particular adaptation could accumulate over time and suddenly result in a major morphologic shift.

Note the talk of "major morphological shift." It's clear that Ray Bohlin is confused about the speciation events that take place in the fossil record.

You know what's coming next, don't you? Watch for hopeful monsters.

But even in 1984 (when evolutionary developmental biology "evo-devo" was in its infancy) nearly all discussions of developmental gene mutations were discussions of lethal or near lethal changes. As we said in Natural Limits, “Mutations of genes intricately involved in development are what produce hopeless, not hopeful monsters.” In Darwin’s Doubt, following a helpful discussion of punctuated equilibrium along with its many difficulties, Meyer quotes Gould from 2002, “I recognize that we know no mechanisms for the origin of such organismal features other than conventional natural selection at the organismic level” (p. 149).

I bet you were surprised that this creationist post got around to defending Darwin's Doubt! (Not.) What we're seeing is a full court press to promote and defend Stephen Meyer. It's a little embarrassing to watch. I'm actually beginning to feel sorry for them.

You probably weren't surprised that hopeful monsters reared their ugly heads because that's just what you'd expect from IDiots who don't understand what they are talking about. (BTW, I don't know where the Gould quote comes from. Does anyone have a copy of Meyer's book?)²

It doesn't get any better ...

Indeed, in 1993 Gould and Eldredge published a review paper in Nature announcing that punctuated equilibrium had come of age. But towards the end of the paper under the heading of Difficulties and Prospects, they highlight the questions raised by evolutionary biologists. After dismissing a few of those objections, they admit “But continuing unhappiness, justified this time, focuses upon claims that speciation causes significant morphological change, for no validation of such a position has emerged.”

The question posed by Gould & Eldredge refers to an explanation of the coupling between speciation events (cladogenesis) and morhological change in the fossil record. Why do the, often minor, morphological changes associated with new species arise suddenly during cladogenesis rather than gradually as one species transforms into another?

They offer an explanation in the very next paragraph of the 1993 paper and it's the same explanation that Gould prefers ten years later in The Structure of Evolutionary Theory. Here's what they said in 1993 ...

We believe that the solution to this dilemma may be provided in a brilliant but neglected suggestion of Futuyma. He holds that morphological change may accumulate anywhere along the geological trajectory of a species. But unless that change be "locked up" by acquisition of reproductive isolation (that is, speciation), it cannot persist or accumulate and must be washed out during the complexity of interdigitation through time among varying populations of a species. Thus, species are not special because their origin permits a unique moment for instigating change, but because they provide the only mechanism for protecting change. Futuyma writes: "In the absence of reproductive isolation, differentiation is broken down by recombination. Given reproductive isolation, however, a species can retain its distinctive complex of characters as its spatial distribution changes along with that of its habitat or niche. . . Although speciation does not accelerate evolution within populations, it provides morphological changes with enough permanence to be registered in the fossil record. Thus, it is plausible to expect many evolutionary changes in the fossil record to be associated with speciation."

That sounds quite reasonable to me. I wonder why Ray Bohlin didn't mention it? Gould devotes five pages (798-802) to it in The Structure of Evolutionary Theory. It's inconceivable that Ray Bohlin didn't study that big book before posing as an expert on punctuated equilibria, isn't it?

Ray Bohlin continues ....

As Meyer spells out, Eldredge and Gould postulated that the speciation event itself was involved in bringing about abrupt morphological change. But as Meyer makes clear, there was no biology behind the claim, just an observation of the fossil record. Using development as the location of such change has proven extremely difficult, as Meyer also points out, especially when discussing the origin of the major body plans that appear in the Cambrian explosion. Body plans are set early in development and mutations in these early processes are universally disadvantageous.

Puntuated equilibria have nothing to do with the Cambrian explosion. Conflating the two is the mark of .... an idiot.

Punk Eek was dead over twenty years ago but persisted on the coattails of Stephen Gould’s considerable and deserved celebrity. But with him gone, his and Elderdege’s unique contribution to evolutionary theory is finally passing quietly away.

Now do you know why we call them IDiots?

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1. It's a part of a bigger war between rationalism and superstition.

2. UPDATE A reader, Paul C. Anagnostopoulos, supplied the reference. It's on page 710. Here's the complete quote from Gould in context. It's part of a discussion about the possibility of species selection.

Several Darwinian strict constructionists, Richard Dawkins and Daniel Dennett in particular, hold that almost everything of interest in evolutionary biology either inheres in, or flows form, natural selection's power to craft the intricate and excellent design of organisms—"organized adaptive complexity," in Dawkins's favorite phrase. ... I do not deny the wonder, or the powerful importance, or organized adaptive complexity. I recognize that we know no mechanism for the origin of such organismal features other than conventional natural selection at the organismal level—for the sheer intricacy and elaboration of good biomechanical design surely preclude either random production, or incidental origin as a side consequence of active processes at other levels. But I decry the parochialism of basking so strongly in the wonder of organismal complexity that nothing else in evolution seems to matter. Yet many Darwinian adaptationists adopt this narrow and celebratory stance in holding, for example, that neutrality may reign at the nucleotide level, but still be "insignificant" for evolution because such changes impose no immediate effects upon organismal phenotypes; or that species selection can regulate longstanding and extensive trends in single characters, but still maintains no "importance in evolution because such a process can't construct an intricate organismal phenotype or numerous, developmentally correlated traits.

Gould, S.J. and Eldredge, N. (1993) Punctuated equilibrium comes of age. Nature 366:223-227. [Text]

Gould, S.J. (2002) The Structure of Evolutionary Theory. Harvard University Press.