|Feature Article - October 2008|
|by Do-While Jones|
At a small meeting on the future of evolutionary thought taking place at the Konrad Lorenz Institute for Evolution and Cognition Research in Altenberg, Austria, evolutionists unveiled yet another version of the theory of evolution.
If the theory of evolution were a computer operating system, the Postmodern Synthesis would be “Evolution 3.0.” By way of review, here are the release notes for previous versions of the theory of evolution.
Evolution 1.0, of course, was Darwinian Evolution. It was built on the notion that climate, diet, and exercise cause inheritable changes that are filtered by natural selection, resulting in a gradual progression from one species to another. It had to be abandoned when subsequent studies of genetics showed that acquired characteristics are not inherited.
Evolution 2.0 was Neo-Darwinian Evolution, also sold under the name, Modern Synthesis. It featured the radical new idea that random mutations (not climate, diet, and exercise) cause inheritable changes that are filtered by natural selection. But, like Darwinian evolution, it suffered from the problem that it was inconsistent with the fossil record. So, Evolution 2.1 incorporated the Hopeful Monster theory. This was the notion that the random mutations were so great that a dinosaur could lay an egg, and a bird might hatch out. This would explain why there are no transitional forms in the fossil record. But the Hopeful Monster theory was not a huge success in the evolutionary marketplace, so it was quickly replaced with Evolution 2.2. Evolution 2.2 replaced the Hopeful Monster theory with Punctuated Equilibrium. Punctuated Equilibrium suggested that there are periods when evolution takes lots of small steps in a short period of time, but then remains stable for long periods of time. As evolutionists put it,
Pigliucci and Kirschner think that the capacity of small genetic changes to trigger large shifts results in waves of innovation separated by seeming lulls in which evolution stablizes [sic] and integrates the new arrangements. This matches some aspects of the fossil record, where bursts of innovation and diversification are interspersed by much longer periods of stasis — a pattern known as punctuated equilibrium, first described by the late Stephen Jay Gould and Niles Eldredge of the American Museum of Natural History in the 1970s. Gilbert, who studies turtles, sees something similar: "Turtle biologists joke that one Tuesday in the late Triassic there weren't any turtles, and by the weekend the world was full of turtles. One reason why might be that it's not all that hard to make a shell — all the genes are probably there already, and it doesn't take many changes to get a shell." 1
One wonders why he thinks “all the genes are probably there already,” and that it isn’t hard to make a shell, but let’s not get distracted.
So now we come to postmodern synthesis, which we like to call “Evolution 3.0.”
Its agenda is, pretty explicitly, to go beyond the 'modern synthesis' that has held sway in evolutionary theory since the middle of the twentieth century. 2
Later the same day, Günter Wagner, an evolutionary theorist at Yale University in New Haven, Connecticut, puts up a slide bearing the words 'Postmodern Synthesis'. Pigliucci is moved to make an editorial suggestion from the floor: "I'd really rather we didn't use that term." Wagner says the slide was intended to be tongue-in-cheek, but Pigliucci is worried about the impression the word creates: "If there's one thing we don't want, it's for people to get the idea that there's a bunch of evolutionary theories out there, and that they're all equal." 3
Despite his desire, people should get that idea because there really are a bunch of evolutionary theories out there, and they are all equally inadequate.
We are going to let evolutionists explain postmodern synthesis to you in their own words. Unfortunately, their own words are words like, “pluralist, multilevel causality”, “decentering”, “phenotype” and “genotype.” Don’t worry. We will explain these terms after you have seen them used in context.
Pigliucci expresses his hope of "moving from a gene-centric view of causality in evolution to a pluralist, multilevel causality". Postmodernists in the humanities call this 'decentering', and they are all for it. 4
Translation: Pigliucci disagrees with the notion that changes to genes are the one and only thing that cause evolution. He thinks there are several different causes. So, instead of centering attention on the genes, he wants to “decenter” and spread out attention on a number of different factors. (We will get to those different factors later.)
Between about 1920 and 1940, researchers such as the American Sewall Wright and the Englishmen Ronald Fisher and J. B. S. Haldane took Charles Darwin's ideas about natural selection and Gregor Mendel's insights into how traits pass from parents to offspring — which many biologists of the time believed antithetical — and fused them into a mathematical description of the genetic makeup of populations and how it changes. That fusion was the modern synthesis. It treats an organism's form, or phenotype, as a readout of its hereditary information, or genotype. Change is explained as one version of a gene being replaced by another. Natural selection acts by changing the frequency of genes in the next generation according to the fitness of phenotypes in this one. In this world view, the gene is a black box, its relationship to phenotype is a one-way street, and the environment, both cellular and external, is a selective filter imposed on the readout of the genes, rather than something that can influence an organism's form directly. 5
You can think of a phenotype as something that gets built, and the genotype as the blueprint for building it. In other words, the genotype is the information stored in the DNA molecule, and the phenotype is the kind of animal that gets built from that DNA.
With that in mind, we can explain the previous paragraph. Darwin had some goofy ideas that characteristics acquired by an individual through diet, exercise, and climate could be passed on to children. Gregor Mendel, however, did some experiments with pea plants that led to the discovery of genes. Modern scientists now know the difference between acquired characteristics and inherited characteristics. So, the modern synthesis is the combination of Mendel’s understanding of genetics with Darwin’s concept of natural selection.
In reality, most characteristics are determined by combinations of genes. But, to simplify the discussion, let’s pretend there is just one gene that determines eye color. There are several variations of this gene. One produces brown eyes. One produces blue eyes. One produces green eyes. When they say, “Natural selection acts by changing the frequency of genes in the next generation according to the fitness of phenotypes in this one,” here’s what they mean: If there is some reason why blue eyes are more conducive to survival than brown eyes or green eyes, then the percentage of the population with blue eyes will increase at the expense of the other colors. So, if most of the population had brown eyes to begin with, but survival of the fittest caused the proportion of individuals with blue eyes to increase, then the population “evolved.” The important thing to realize is that they are using the term “evolve” to mean “change in percentage” not “change in characteristics.” There were individuals with brown, blue, and green eyes to begin with. No new colors evolved. All that changed was the ratios of the existing colors to each other.
Natural selection really does (to some limited extent) change the relative numbers of individuals with existing characteristics in a population.
The sentence that evolutionists are arguing about is, “In this world view, the gene is a black box, its relationship to phenotype is a one-way street, and the environment, both cellular and external, is a selective filter imposed on the readout of the genes, rather than something that can influence an organism's form directly.” What that sentence means is that genes completely determine the characteristics of the creature. The environment and life experiences of the creature don’t change the genes. That’s a problem because, if that is true, then the only thing that can change genes is a reproductive error that introduces a random change to the gene. Let’s let them explain why this is a problem.
What's wrong with this picture, say the would-be extenders at Altenberg and elsewhere, is what it leaves out. Molecular biology, cell biology and genomics have provided a much richer picture of how genotypes make phenotypes. The extenders claim that enough insights have now come from this and other research for it to be time to re-examine problems that the modern synthesis doesn't address. These problems include some of the key turning points in evolution: the patterns and changes seen in the fossil record as new branches spring from the tree of life and new anatomies — skeletons, limbs, brains — come into being. "When the public thinks about evolution, they think about the origin of wings and the invasion of the land," says Graham Budd, a palaeobiologist at the University of Uppsala, Sweden. "But these are things that evolutionary theory has told us little about." 6
Here’s what they are saying: Random changes to genes just can’t explain remarkable innovations like the origin of winged creatures and the evolution of land creatures from sea creatures. Evolutionary theory honestly has no explanation for innovation. Dumb luck just doesn’t cut it. But, we are starting to learn things about embryonic development that suggest that maybe the environment can change how genes are expressed in the womb. So, maybe (they hope) there is some way that the environment might affect the genes.
"The modern synthesis is remarkably good at modelling the survival of the fittest, but not good at modelling the arrival of the fittest." To explain the production of novel features, such as limbs and feathers, Gilbert and like-minded biologists want a theory in which the environment is defined broadly enough to include the developing body, which is the primary context in which the genes are expressed. Genes shape this developing environment, but the dynamic environment also shapes the expression of the genes. And it does so directly, rather than through some later selection. "The gene will continue to be centre stage," says Gilbert, "but it will be seen as both active and acted upon. It's not going to be the unmoved mover." 7
It was so long ago that I don’t remember which creationist first said it, but I know I have heard creationists say that natural selection explains survival of the fittest but not arrival of the fittest. This is the first time I’ve seen an evolutionist admit it in print.
It is amusing that, after all these years, evolutionists are starting to go back to Darwin’s idea that diet, exercise, and climate can produce inheritable changes. They don’t say so explicitly, but Gilbert was beating around that bush in the previous quote.
It is important to note that they don’t have any positive reason to believe that the environment can cause genetic changes. They finally have to admit that random chance is not sufficient to do the job, and there must be some other explanation. The environment must be that other explanation by default because they just can’t think of anything else.
The importance of the environment acting on the genome can be seen in plasticity, the ability of the same genes to give rise to radically different phenotypes in different conditions — as studied by several of the Altenberg group. 8
Microbiologists have discovered that a gene that produces a certain structure in one animal produces a different structure in a different animal. At least, it appears that way. It’s hard to tell because of complex gene interaction. But this apparent ability for a gene to produce different structures is called “plasticity.” A gene isn’t so rigid that it can only produce one thing. Genes appear to be flexible, or plastic.
In 1896 James Baldwin, an American psychologist, suggested that over the generations, tricks that at first have to be learned can become hard-wired as genes fix variations caused by the environment. "It could be that the plants arrive in a new environment and hang on thanks to plasticity — it gains time for natural selection to kick in," says Pigliucci. 9
The idea that learned behavior can be inherited is without factual support, and seems improbable. Baldwin suggested the idea 112 years ago, and nobody has confirmed it yet, so that would suggest it isn’t true. But still, Pigliucci says, “it could be.”
The problem is testing such ideas. Newman suggests that knocking out the genes that stabilize development in model laboratory organisms might provide insights, but extrapolating back from modern organisms to their distant ancestors is fraught with problems. It is difficult to see how such an approach can get beyond the theoretical, says Budd, adding that what evidence there is weighs against Newman's hypothesis. 10
Knocking out genes might prove that it is possible for something to happen, but it doesn’t prove that it did happen. Of course, the real problem is not getting rid of existing genes. The real problem is explaining how those genes arose in the first place.
Confusing what can happen and what did happen is a common criticism of the ideas raised at Altenberg. 11
And, of course, it is a valid criticism of most of the theory of evolution. Just because something can happen doesn’t mean it did happen. Furthermore, most evolutionary ideas are based on the argument that maybe, somehow, through some process we don’t really understand, it could happen—therefore it must have happened.
Since there really isn’t any good evidence to suggest that the postmodern synthesis is the correct explanation of evolution, the defenders of modern synthesis are holding their ground.
But there is little evidence so far that genetic change in wild populations takes this course, says Wagner. "The idea that environmentally induced changes are the path-breaker for genetic fixation is an old one, but I'm not yet convinced that's how it works in real populations," he says. 12
Yes, the notion that environmentally induced changes can be inherited goes back to Darwin, and has been rejected by geneticists from the time of Mendel to the present.
"These notions haven't forced us to change the neo-darwinian paradigm," says Jerry Coyne, an evolutionary geneticist at the University of Chicago. Coyne has little time for "evo-devotees" who think that the discipline will cause a revolution in biology. Researchers coming at evolution from population genetics are particularly resistant to any attempt to displace natural selection from the place at the heart of evolutionary theory that the modern synthesis provided it with. "The whole thing about natural selection being an insufficient paradigm seems grossly overblown," says Coyne. "There are a lot of interesting new things coming out that will change our view of evolution. But to say the modern synthesis is incomplete or fatally flawed is fatuous." 13
We described evo-devo in the June, 2006, newsletter, so we won’t cover that ground in detail again. Suffice it to say that evo-devo is based on the unsubstantiated notion that the first living thing had remarkably versatile DNA that could build just about anything. Creatures differ not in the “tools” in their DNA “tool kit.” They differ in how those common tools are used during development.
Here is what some evolutionists are now saying about evo-devo.
The true message of evo-devo, Carroll says, is that developmental processes have evolved in a way that allows small aspects of form to be tweaked without affecting the whole organism — something which tends to reinforce the modern synthesis's view of evolution as incremental. "Because we can get large effects when we manipulate genes in development, the spectre that these things have happened in history is out there," says Carroll. "But just because we can make freaky-looking animals in one step, I'm unwilling to say that evolution works that way." 14
The differences of opinion suggest that, although evo-devo may once have looked as if it would unify population genetics and development, so far it has done more to give new voice to important problems that had been pushed to the margin — this was a strong note at Altenberg, making the meeting as much about revivalism as revolution. "Originally, the idea was that evo-devo was going to be the synthesis between evolution and development — now it is part of what needs to be done to get there," says Alan Love, a philosopher of science at the University of Minnesota in Minneapolis who attended Altenberg. "There is still a lot of outstanding work to do on fitting the pieces together, but no consensus on how to go about that right now." Nevertheless, he says, that's no cause for alarm. 15
Translation: It is cause for alarm!
You aren’t going to hear any of this in public schools or in the mainstream media. Here’s why:
As Gould discovered, creationists seize on any hint of splits in evolutionary theory or dissatisfaction with Darwinism. In the past couple of decades, everyone has become keenly aware of this, regardless of their satisfaction or otherwise with the modern synthesis. "You always feel like you're trying to cover your rear," says Love. "If you criticize, it's like handing ammunition to these folks." So don't criticize in a grandstanding way, says Coyne: "People shouldn't suppress their differences to placate creationists, but to suggest that neo-Darwinism has reached some kind of crisis point plays into creationists' hands," he says. 16
They don’t dare let the truth out. They have to present a brightly painted façade to the public to hide the rotting structure behind it. That’s why they have to censor the public school science curriculum.
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John Whitfield, Nature, 18 September 2008, “Biological theory: Postmodern evolution?”, pp. 281-284