On November 7-9 there was a special meeting of London’s Royal Society on “New Trends in Evolutionary Biology: Biological, Philosophical, and Social Science Perspectives.” I believe it was organized by Denis Noble, a physiologist who believes that modern views about evolution are ripe for a thorough revision. Many of the speakers at the meeting are part of the “Third Way of Evolution” group, in which various mechanisms, supposedly ignored by the rest of us hidebound neo-Darwinists, are said to play major roles in evolution (the other two “ways” are creationism and Neo-Darwinism).
I’ve criticized Noble and the views of his colleagues before (see here and here, for instance). Here I’ll briefly reprise the themes of this new conference, and why I think that, while the mechanisms discussed are of interest, they pose no danger to the existing evolutionary paradigm; nor is there enough data to show that these mechanisms are common in nature—or even operate at all.
First, though, it’s worth noting that of the 26 presenters at the meeting, 10 were funded by Templeton’s “extended evolutionary synthesis” grant—an 8 million dollar grant over three years. Further, a representative of the Templeton Foundation was present at the meeting, presumably making sure his stable of prized thoroughbreds were running well. The grant and the meeting seem to me to represent one aim of Templeton: to show the weakness of the current evolutionary paradigm. Why they want to do this is beyond me, but it’s clear that the researchers funded by the grant are enthusiasts who have an agenda, one that partly includes self-promotion.
A good summary of the meeting, by the estimable Carl Zimmer, appears in Quanta Magazine as a longish piece, “Scientists seek to update evolution.” I won’t go through the issues raised, except to say they include the following four claims; and the critical take on these is not Zimmer’s but mine:
Epigenetics: This is the new “Lamarckian” view that environmentally-induced changes in the DNA, often affecting the methylation of DNA bases, could be an important contributor to evolution. The problem with this is that these changes are not permanent, and are often effaced after one or two generations. The record, I think, now stands at 31 generations before the environmentally-induced changes are wiped clean. But this provides no permanent basis for permanent adaptive change, which is the huge problem with the epigenetics “paradigm.” Further, when real adaptations can be genetically mapped in organisms, they always reside in the DNA sequence itself and not in the temporary alterations of DNA bases produced by the environment. Further, because environmentally induced epigenetic changes are temporary, they can’t participate in evolution by genetic drift, either.
Now there are adaptive epigenetic changes that are coded in the DNA itself: genes that code for instructions like, “Methylate bases at positions X, Y, and Z.” But those instructions evolved by conventional natural selection, and are not the types of epigenetic changes touted by promoters of the New Paradigm.
Development. Zimmer says some speakers emphaszied that development can constrain evolution: only certain evolutionary changes are possible given the evolved developmental system of organisms. (Haldane once used the example that humans couldn’t evolve into angels because they had neither the limb buds for wings nor the moral precursors!). But this is nothing new, and has been discussed for decades in the Modern Synthesis.
Plasticity. As is well known, organisms can change their appearance, behavior, and physiology depending on their environment. Some of this is simply a “shock response” with no adaptive value, while other forms of plasticity are evolved adaptations that reside in the DNA (cats grow longer fur when it’s cold, rotifers develop predator-deterring spines when put in water with fish “odor”, etc.). But the New Paradigmists say that nonadaptive plasticity can actually initiate an adaptive evolutionary change. It’s not really clear how this would happen, and in fact we have no good examples of it happening. We have, on the other hand, plenty of examples of adaptive plasticity that evolved by conventional natural selection: organisms regularly exposed to different environments can, over time, evolve switchable genetic programs (as in cat fur length) to respond to a new environment.
Niche construction. This is the argument that an organism, by adapting to its current environment, actually changes the selective pressures that impinge on it, thus opening up further evolutionary pathways. The classic example, as Zimmer notes, is the beaver: by adapting to build a pond by cutting down trees and making dams, the beaver now occupies a new habitat, which also includes its lodge. That could present new ways for the beaver to evolve as it now lives in a pond-ish environment.
But this is not new, either, and fits well within the Modern Synthesis. As Ernst Mayr once pointed out, many new adaptations evolve not by a change in the external environment itself, but by the organism behaviorally entering a new environment when that environment offers adaptive advantages. By making forays on land, for instance, lobe-finned fish suddenly were able to access a bunch of new food types previously unavailable. And of course once you’re moving about on land, selection will favor all kinds of new adaptations, like shelled eggs and big lungs that handle air. Similarly, warm-blooded animals, by evolving homeothermy, acquire a thin layer of warm air around their bodies, providing a good niche for ectoparasites, to which the animal must now adapt. I am in fact surprised that niche construction is seen as something radically new, since it follows ineluctably from adaptation itself.
While most of the participants in the Royal Society meeting espoused these kinds of revisions, you can see that they’re neither new nor nor have much EVIDENCE supporting them as strong challenges to the existing evolutionary paradigm.
After Carl Zimmer summarizes some of these matters, he mentions the pushback that people had against the idea that evolution is in trouble. I’ll just give one excerpt from his piece, involving a claim by Dennis Noble that organisms have an ability to detect stress and then rapidly rearrange their genomes to respond adaptively to that stress:
To illustrate this new view, Noble discussed an assortment of recent experiments. One of them was published last year by a team at the University of Reading. They did an experiment on bacteria that swim by spinning their long tails.
First, the scientists cut a gene out of the bacteria’s DNA that’s essential for building tails. The researchers then dropped these tailless bacteria into a petri dish with a meager supply of food. Before long, the bacteria ate all the food in their immediate surroundings. If they couldn’t move, they died. In less than four days in these dire conditions, the bacteria were swimming again. On close inspection, the team found they were growing new tails.
That didn’t sound right to Shuker [David Shuker of the University of St Andrews], and he was determined to challenge Noble after the applause died down.
“Could you comment at all on the mechanism underlying that discovery?” Shuker asked.
Noble stammered in reply. “The mechanism in general terms, I can, yes…” he said, and then started talking about networks and regulation and a desperate search for a solution to a crisis. “You’d have to go back to the original paper,” he then said.
While Noble was struggling to respond, Shuker went back to the paper on an iPad. And now he read the abstract in a booming voice.
“‘Our results demonstrate that natural selection can rapidly rewire regulatory networks,’” Shuker said. He put down the iPad. “So it’s a perfect, beautiful example of rapid neo-Darwinian evolution,” he declared.
This exemplifies the problem: enthusiasts for the Third Way blather on about new mechanisms, and write dataless paper after dataless paper about them, but when the mechanisms are examined closely they’re found to be not so revolutionary after all.
Why, then, are people suddenly touting a revision of evolutionary theory? (This isn’t all new; Steve Gould tried it with punctuated equilibrium, proposing a mechanism for episodic evolutionary change that has now been discarded.) One reason is, of course, that Templeton is funding this project big time. Where the money goes, so goes the research. The other was suggested at the meeting by my friend Doug Futuyma, not only an evolutionist but someone with a deep knowledge of the history of evolutionary thought. As Zimmer reports:
“We must recognize that the core principles of the Modern Synthesis are strong and well-supported,” Futuyma declared. Not only that, he added, but the kinds of biology being discussed at the Royal Society weren’t actually all that new. The architects of the Modern Synthesis were already talking about them over 50 years ago. And there’s been a lot of research guided by the Modern Synthesis to make sense of them.
Take plasticity. The genetic variations in an animal or a plant govern the range of forms into which organism can develop. Mutations can alter that range. And mathematical models of natural selection show how it can favor some kinds of plasticity over others.
If the Extended Evolutionary Synthesis was so superfluous, then why was it gaining enough attention to warrant a meeting at the Royal Society? Futuyma suggested that its appeal was emotional rather than scientific. It made life an active force rather than the passive vehicle of mutations.
“I think what we find emotionally or aesthetically more appealing is not the basis for science,” Futuyma said.
Still, he went out of his way to say that the kind of research described at the meeting could lead to some interesting insights about evolution. But those insights would only arise with some hard work that leads to hard data. “There have been enough essays and position papers,” he said.
Doug is right–new insights could be in the offing. But, like him, I’d say, “Where’s the beef?” (The “beef” constitutes data and evidence.)
Doug has written a paper that summarizes and rebuts many of the supposedly serious challenges to modern evolutionary biology, and you can get it free by going to this link. The screen provides three items that can be read on SpringerLink for free; the second is Doug’s chapter. Just go to “Download Sample Pages 2 PDF” at the bottom of the page, and you’ll get Doug’s whole paper for free. If you’re an evolutionist, this is a must-read paper, but I’d suggest that evolution-friendly readers have a look as well. The whole paper is worth reading, but if you want to just get Doug’s take on challenges to modern evolutionary theory, read section 4, from pages 53-70.
Finally, Suzan Mazur, a journalist who has long touted a total scrapping of modern evolutionary theory, wrote a piece about the conference at PuffHo (wouldn’t you know?) called “Pterosaurs hijack Royal Society Evo meeting.” It’s a bizarre piece, all over the map, but Mazur seems to have given up her crusade against modern evolutionary biology, now appearing to be on another (and better) crusade against Templeton’s funding of this kind of nonsense.
Bottom line: Modern evolutionary theory is not in trouble–far from it. Maybe sometime a New Paradigm will come around, but this isn’t it. The noise we heard from London, outside of a few papers by people like Futuyma, is the noise of Templeton’s prize horses jockeying for money and fame.