#1 Why everything you've been told about evolution is wrong
03-22-2010, 02:47 AM
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- Jun 2008
....Inevitably, those of us who aren't professional scientists have to take a lot of science on trust. And one of the things that makes it so easy to trust the standard view of evolution, in particular, is amply illustrated by the legend of the Nasa astronomers: the doubters are so deluded or dishonest that one needn't waste time with them. Unfortunately, that also makes it embarrassingly awkward to ask a question that seems, in the light of recent studies and several popular books, to be growing ever more pertinent. What if Darwin's theory of evolution – or, at least, Darwin's theory of evolution as most of us learned it at school and believe we understand it – is, in crucial respects, not entirely accurate?
.....Take, to begin with, the Swedish chickens. Three years ago, researchers led by a professor at the university of Linköping in Sweden created a henhouse that was specially designed to make its chicken occupants feel stressed. The lighting was manipulated to make the rhythms of night and day unpredictable, so the chickens lost track of when to eat or roost. Unsurprisingly, perhaps, they showed a significant decrease in their ability to learn how to find food hidden in a maze.
The surprising part is what happened next: the chickens were moved back to a non-stressful environment, where they conceived and hatched chicks who were raised without stress – and yet these chicks, too, demonstrated unexpectedly poor skills at finding food in a maze. They appeared to have inherited a problem that had been induced in their mothers through the environment. Further research established that the inherited change had altered the chicks' "gene expression" – the way certain genes are turned "on" or "off", bestowing any given animal with specific traits. The stress had affected the mother hens on a genetic level, and they had passed it on to their offspring.
The Swedish chicken study was one of several recent breakthroughs in the youthful field of epigenetics, which primarily studies the epigenome, the protective package of proteins around which genetic material – strands of DNA – is wrapped. The epigenome plays a crucial role in determining which genes actually express themselves in a creature's traits: in effect, it switches certain genes on or off, or turns them up or down in intensity. It isn't news that the environment can alter the epigenome; what's news is that those changes can be inherited. And this doesn't, of course, apply only to chickens: some of the most striking findings come from research involving humans.
One study, again from Sweden, looked at lifespans in Norrbotten, the country's northernmost province, where harvests are usually sparse but occasionally overflowing, meaning that, historically, children sometimes grew up with wildly varying food intake from one year to the next. A single period of extreme overeating in the midst of the usual short supply, researchers found, could cause a man's grandsons to die an average of 32 years earlier than if his childhood food intake had been steadier. Your own eating patterns, this implies, may affect your grandchildren's lifespans, years before your grandchildren – or even your children – are a twinkle in anybody's eye.
It might not be immediately obvious why this has such profound implications for evolution. In the way it's generally understood, the whole point of natural selection – the so-called "modern synthesis" of Darwin's theories with subsequent discoveries about genes – is its beautiful, breathtaking, devastating simplicity. In each generation, genes undergo random mutations, making offspring subtly different from their parents; those mutations that enhance an organism's abilities to thrive and reproduce in its own particular environment will tend to spread through populations, while those that make successful breeding less likely will eventually peter out.
As years of bestselling books by Dawkins, Daniel Dennett and others have seeped into the culture, we've come to understand that the awesome power of natural selection – frequently referred to as the best idea in the history of science – lies in the sheer elegance of the way such simple principles have generated the unbelievable complexities of life. From two elementary notions – random mutation, and the filtering power of the environment – have emerged, over millennia, such marvels as eyes, the wings of birds and the human brain.
Yet epigenetics suggests this isn't the whole story. If what happens to you during your lifetime – living in a stress-inducing henhouse, say, or overeating in northern Sweden – can affect how your genes express themselves in future generations, the absolutely simple version of natural selection begins to look questionable......
Epigenetics is the most vivid reason why the popular understanding of evolution might need revising, but it's not the only one. We've learned that huge proportions of the human genome consist of viruses, or virus-like materials, raising the notion that they got there through infection – meaning that natural selection acts not just on random mutations, but on new stuff that's introduced from elsewhere. Relatedly, there is growing evidence, at the level of microbes, of genes being transferred not just vertically, from ancestors to parents to offspring, but also horizontally, between organisms. The researchers Carl Woese and Nigel Goldenfield conclude that, on average, a bacterium may have obtained 10% of its genes from other organisms in its environment.
To an outsider, this is mind-blowing: since most of the history of life on earth has been the history of micro-organisms, the evidence for horizontal transfer suggests that a mainly Darwinian account of evolution may be only the latest version, applicable to the most recent, much more complex forms of life. Perhaps, before that, most evolution was based on horizontal exchange. Which gives rise to a compelling philosophical puzzle: if a genome is what defines an organism, yet those organisms can swap genes freely, what does it even mean to draw a clear line between one organism and another? "It's natural to wonder," Goldenfield told New Scientist recently, "if the very concept of an organism in isolation is still valid at this level." In natural selection, we all know, the fittest win out over their rivals. But what if you can't establish clear boundaries between rivals in the first place?
.......And now, if epigenetics and other developments are coming to suggest that environment can alter heredity, the very terms of the debate – of nature versus nurture – suddenly become shaky. It's not even a matter of settling on a compromise, a "mixture" of nature and nurture. Rather, the concepts of "nature" and "nurture" seem to be growing meaningless. What does "nature" even mean if you can nurture the nature of your descendants?
This is one central argument of Shenk's new book, subheaded Why Everything You've Been Told About Genetics, Talent and IQ is Wrong. All our popular notions about talent and "genetic gifts", he points out, start to collapse if the eating habits of Tiger Woods's ancestors, for example, might have played a role in Woods's golfing abilities. (Woods always crops up in discussions on the origins of genius; more recently, he has started cropping up in evolutionary psychology discussions about whether promiscuity is inevitable.)
"What all this evidence shows is that we need a much more subtle and nuanced understanding of Darwinism and natural selection," Shenk says. "I think that's inevitably going to happen among scientists. The question is how much nuance will carry over into the public sphere . . . it's really funny how difficult it is to have this conversation, even with a lot of people who understand the science. We're stuck with a pretty limited way of viewing all this, and I think part of that comes from the terms" – such as nature and nurture – "that we have."
Among the arsenal of studies at Shenk's disposal is one published last year in the Journal of Neuroscience, involving mice bred to possess genetically inherited memory problems. As small recompense for having been bred to be scatterbrained, they were kept in an environment full of stimulating mouse fun: plenty of toys, exercise and attention. Key aspects of their memory skills were shown to improve, and crucially so did those of their offspring, even though the offspring had never experienced the stimulating environment, even as foetuses.
"If a geneticist had suggested as recently as the 1990s that a 12-year-old kid could improve the intellectual nimbleness of his or her future children by studying harder now," writes Shenk, "that scientist would have been laughed right out of the hall." Not so now.
03-22-2010, 02:48 AM
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- Jun 2008
And then there is Jerry Fodor, the American philosopher. I started reading What Darwin Got Wrong, the new book he has co-authored with the cognitive scientist Massimo Piattelli-Palmarini, one morning, along with that day's first coffee. A few pages later, as the coffee kicked in, I grasped with astonishment what Fodor had done. He hadn't just identified evidence that natural selection was more complicated than previously thought – he'd uncovered a glaring flaw in the whole notion! Natural selection, he explains, simply "cannot be the primary engine of evolution". I got up and refilled my cup. But by the time I returned, his argument had slipped from my grasp. Suddenly, he seemed obviously wrong, tied up in philosophical knots of his own creation. I alternated between these two convictions. Was Fodor's critique so devastatingly correct that his critics – Dawkins, Dennett, the Cambridge philosopher Simon Blackburn, and many others – simply couldn't see it? Had he actually managed to . . . but then it slipped away again, vanishing into mental fog.
I called Fodor and asked him to explain his point in language an infant school pupil could understand. "Can't be done," he shot back. "These issues really are complicated. If we're right that Darwin and Darwinists have missed the point we've been making for 150 years, that's not because it's a simple point and Darwin was stupid. It's a really complicated issue."
Fodor's objection is a distant cousin of one that rears its head every few years: doesn't "survival of the fittest" just mean "survival of those that survive", since the only criterion of fitness is that a creature does, indeed, survive and reproduce? The American rightwing noisemaker Ann Coulter makes the point in her 2006 pro-creationist tirade Godless: The Church of American Liberalism. "Through the process of natural selection, the 'fittest' survive, [but] who are the 'fittest'? The ones who survive!" she sneers. "Why, look – it happens every time! The 'survival of the fittest' would be a joke if it weren't part of the belief system of a fanatical cult infesting the Scientific Community."
This argument, perhaps uniquely among all arguments ever made by Coulter, feels persuasive, not least because it is a reasonable criticism of some pop-Darwinism. In fact, though, it's entirely possible for scientists to measure fitness using criteria other than survival, and thus to avoid circular logic. For example, you might hypothesise that speed is a helpful thing to have if you're an antelope, then hypothesise the kind of leg structure you'd want to have, as an antelope, in order to run fast; then you'd examine antelopes to see if they do indeed have something approximating this kind of leg structure, and you'd examine the fossil record, to see if other kinds of leg died out.
Fodor's point is more complex than this, although it's also possible that it is not really a point at all: several reviews of the book by professional evolutionary theorists and philosophers have concluded that it is, indeed, nonsense. As far as I can make out, it can be summarised in three steps.
Step one: Fodor notes – undeniably correctly – that not every trait a creature possesses is necessarily adaptive. Some just come along for the ride: for example, genes that express as tameness in domesticated foxes and dogs also seem to express as floppy ears, for no evident reason. Other traits are, as logicians say, "coextensive": a polar bear, for example, has the trait of "whiteness" and also the trait of "being the same colour as its environment". (Yes, that's a brain-stretching, possibly insanity-inducing statement. Take a deep breath.)
Step two: natural selection, according to its theorists, is a force that "selects for" certain traits. (Floppy ears appear to serve no purpose, so while they may have been "selected", as a matter of fact, they weren't "selected for". And polar bears, we'd surely all agree, were "selected for" being the same colour as their environment, not for being white per se: being white is no use as camouflage if snow is, say, orange.)
Step three is Fodor's coup de grace: how, he says, can that possibly be? The whole point of Darwinian evolution is that it has no mind, no intelligence. But to "select for" certain traits – as opposed to just "selecting" them by not having them die out – wouldn't natural selection have to have some kind of mind? It might be obvious to you that being the same colour as your environment is more important than being white, if you're a polar bear, but that's because you just ran a thought-experiment about a hypothetical situation involving orange snow. Evolution can't run thought experiments, because it can't think. "Darwin has a theory that centrally turns on the notion of 'selection-for'," says Fodor. "And yet he can't give an account – nobody could give an account – of how natural selection could distinguish between correlated traits. He waffles."
Those of us baffled by this argument can take solace in the fact that we're not alone. The general response to Fodor among evolutionary thinkers has been a mixture of derision and awkwardness, as if one of their previously esteemed colleagues had entered the senior common room naked. Says Dennett, via email: "Jerry Fodor's book is a stunning demonstration of how abhorrence of an idea (Jerry's visceral dislike of evolutionary thinking) can derange an otherwise clever thinker . . . a responsible academic is supposed to be able to control irrational impulses, [but] Fodor has simply collapsed in the face of his dread and composed some dreadfully bad arguments." What Darwin Got Wrong, Dennett concludes, is "a book that so transparently misconstrues its target that it would be laughable were it not such dangerous mischief".
It would be jawdroppingly surprising, to say the least, were Fodor to be right. A safer, if mealy-mouthed, conclusion to draw is that his work acts as an important warning to those of us who think we understand natural selection. It's probably not a bankrupt concept, as Fodor claims. But nor should laypeople assume that it's self-evidently simple and exhaustively true.
The irony in all this is that Darwin himself never claimed that it was. He went to his deathbed protesting that he'd been misinterpreted: there was no reason, he said, to assume that natural selection was the only imaginable mechanism of evolution. Darwin, writing before the discovery of DNA, knew very well that his work heralded the beginning of a journey to understand the origins and development of life. All we may be discovering now is that we remain closer to the beginning of that journey than we've come to think.
03-22-2010, 10:46 AM
I read a few pieces last week about this. It's interesting.
I'm always struck by how "settled" various issues in science and medicine become once the media (and various interest groups) get done translating them for the general population. This idea about selection and how quickly genes can be turned on or off has actually been around for some time. It raises some doubts about the current direction of evolutionary biology (not about the field itself but about its role).
Likewise, we always hear a lot about some popular pronouncement ("high" cholesterol causes heart disease, for instance) but little about the actual science behind the association (inflammation damages arterial walls, plaque is the repair system). This leads to all kinds of misunderstandings and really bad public policy such as the drive to reduce dietary fat to reduce plaque. When cholesterol numbers decline on draconian diets (and they need to be fairly strict), the cause is a reduction of triglycerides and inflammatory factors (due to low calories) which can also be achieved by reducing carbohydrate metabolism or by short term periodic fasting.
But there is no special interest group in line to receive funding, fame, or glory by telling people to skip eating one day a week or by telling them to drop the toast and fruit for breakfast and stick with eggs or a leftover pork chop. So we drug people to achieve the "right" numbers and bully them when they fail.
03-22-2010, 11:14 AM
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- Mar 2010
Also, people love their fats and their sweets. For example, beef seems to be addictive for me, and as hard as I try there is not substitute for a good old hamburger or a piece of roast beef. Beef and pork are both very rich in calories and in cholestoral, and if we could reduce our intake by half or so we might be healthier and live longer.
I don't wish to diss Darwin considering the fact that he was working long before the miracles of modern science let us look at genes and the like in a quantitative manner. At least the author did not throw intelligent design into the discussion.
03-22-2010, 11:22 AMStep three is Fodor's coup de grace: how, he says, can that possibly be? The whole point of Darwinian evolution is that it has no mind, no intelligence. But to "select for" certain traits – as opposed to just "selecting" them by not having them die out – wouldn't natural selection have to have some kind of mind?
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- May 2008
03-22-2010, 11:31 AM
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- Oct 2009
- Southwest Michigan (in Exile)
What is needed is an open, honest, and civil discussion about both Theories. but unless God or w/e Intelligence is discovered that wont happen.
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- May 2008
03-22-2010, 12:03 PM
Your body is full of parasites that the body has adapted to and actually need. The deadly ecoli bacteria lives in your intestines and helps to regulate the amount of water in your body. The mouth is one of the most germy areas of the body but biologiests are starting to realize that most of the germs in the mouth serve on important purpose. To take up space and keep other more troublesome germs out. No room at the inn, so to speak.
Please don't shoot me
03-22-2010, 12:05 PM
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- May 2008
In any case, what ID "says" tends to vary with the time of day, but it makes more specific claims than what you suggest. Its two foundational ideas are specified complexity, and irreducible complexity.
IC has basically been falsified, or at least shown to have no positive evidence. And this idea certainly does really state that the type of evolution proposed by TTOE is not possible. The big example for a long time was our blood clotting cascade. It was claimed that such a complex interaction of parts could not have evolved, because removing any of the parts would result in a non-functional system. If it would be rendered useless by a single missing peice, no small incremental changes as a result of a mindless process could have produced it. Well, guess what happened when ID'ists proposed this idea? Scientists considered the arguments, then went looking for blood clotting cascades similar to ours in other organisms. and found many examples of blood clotting cascades that functioned with all kinds of missing parts, and were even able to produce a plausible hypothesis for how our cascade formed in a step-wise fashion, using real world examples. Meanwhile, ID'ists pretend their arguments were not addressed.
SC, well... no one has quite figured it out yet, because Dembski himself (it was his brainchild) can't even figure out how to apply his formulas to real world scenarios. But without IC, its useless anyhow.
Last edited by wilbur; 03-22-2010 at 12:09 PM.
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