Give neo-atheist blowhard PZ Myers some credit: when he says it's wrong to tolerate nonsense, he doesn't just mean creationist numbnuttery. Myers also takes a dim view of the way people who affirm the validity of species evolution misrepresent it. In a lecture at the Center For Inquiry in LA earlier this year, he took aim at bad evolutionary biology that equates adaptation with evolution.
So you say natural selection is the driving force behind species evolution? That traits or features in living organisms have each been selected for in a vast, ongiong, billion-year-old tournament between selfish genes? In that case, Myers wants a word with you.
Im watching this video but I don't really understand this stuff....why is he taking such a staunch position on it all, anyway? What agenda is he pushing?
Chance as a real force is a myth. It has no basis in reality and no place in scientific inquiry. For science and philosophy to continue to advance in knowledge, chance must be demythologized once and for all. —RC Sproul
"A lie can travel half way around the world while the truth is putting on its shoes." —Mark Twain
Fair enough, but if you've actually studied biology at all, you'd know he's not saying anything new, just trying to put some internet idiots right about a few things.
He's also being somewhat disingenuous and I think very misleading about selection. Most of the time when he's taking about it he's referring to trivial changes between individuals that don't get selected for, but the major stuff - he refers to arms and legs - DO rely on selection over long periods of time inside populations. He really needs to get into that if he wants to make the point better.
I'm not sure what your reference to the Selfish Gene is, Dawkins would have no issue with anything said here.
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Life, don't talk to me about life - Marvin the Paranoid Android
"Science adjusts it's views based on what's observed. Faith is the denial of observation so that Belief can be preserved." - Tim Minchin, in his beat poem, Storm.
why is he taking such a staunch position on it all, anyway? What agenda is he pushing?
This is a debate that has gone on for ages, but it's not as high-profile (or lucrative) a battle in the culture wars as that of creationism.
Long story short, progress in population genetics has led to the realization among biologists that there are forces that are more important to evolutionary change than natural selection: non-selective processes like mutation, recombination, and genetic drift. Nevertheless, many writers mislead the public with the notions that natural selection is the sole relevant driver of species evolution, and that all biological traits are by definition adaptations, the product of selective wars between selfish genes in their inexorable drive toward self-perpetuation in the struggle for existence, etc. etc. For example, in The Ancestor's Tale, Richard Dawkins asserted: "Natural selection is all-powerful with respect to those visible changes that affect survival and reproduction. Natural selection is the only explanation we know for the functional beauty and apparently "designed" complexity of living things." If that's not unapologetic adaptationism, I don't know what is.
Stephen Jay Gould and Richard Lewontin published a paper in 1979 titled The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme that took this adaptationist thinking to task as the facile oversimplification that it is. One metaphor they used was the spandrel, a feature of a cathedral that was only the decorative workaround necessary for the way a dome fit onto supporting columns, not the main artistic element of the structure. The other metaphor was Dr. Pangloss, the nutty philosopher from Voltaire's Candide whose explanations of everything from human clothing to the horrifying destruction wreaked by the Lisbon earthquake was predicated on the self-validating assumption that things were the way they were because they couldn't be otherwise.
Coming up with plausible scenarios for how traits evolved is as easy as shooting fish in a barrel. As Gould and Lewontin wrote:
quote:We fault the adaptationist programme for its failure to distinguish current utility from reasons for origin (male tyrannosaurs may have used their diminutive front legs to titillate female partners, but this will not explain why they got so small); for its unwillingness to consider alternatives to adaptive stories; for its reliance upon plausibility alone as a criterion for accepting speculative tales; and for its failure to consider adequately such competing themes as random fixation of alleles, production of nonadaptive structures by developmental correlation with selected features (allometry, pleiotropy, material compensation, mechanically forced correlation), the separability of adaptation and selection, multiple adaptive peaks, and current utility as an epiphenomenon of nonadaptive structures. We support Darwin's own pluralistic approach to identifying the agents of evolutionary change.
As Myers points out, a much more disturbing problem with adaptationist thinking is that it forms the basis for racist and sexist ideas that make it seem like there are scientific rationales for social inequities and that cultural biases have their roots not in personal prejudice but in biological fact.
"Natural selection is all-powerful with respect to those visible changes that affect survival and reproduction. Natural selection is the only explanation we know for the functional beauty and apparently "designed" complexity of living things." If that's not unapologetic adaptationism, I don't know what is.
No, no, give Dawkins credit. He says "those visible changes that affect survival and reproduction". Not for all changes. And then he goes on "for the functional beauty and "apparently "designed" complexity of living things." Not for every feature of living things. What he's doing is taking an adaptationist view ... of things which actually are adaptations! This is no vice.
He does not say (a) that all features are adaptive (b) that, failing that, we can always know which features are adaptive (c) that it is always clear what a feature that is adaptive was adapted for; it is these that I take to be the faults of adaptationism.
Having said which, I'm not sure that there are any adaptationists in the sense of someone who would affirm (a) or (b) or (c): there are merely particular cases where biologists have convinced themselves of an adaptive story behind a particular feature of an organism when they are not really warranted in doing so.
What he's doing is taking an adaptationist view ... of things which actually are adaptations! This is no vice.
What it is is a tautology: Natural selection is important in terms of adaptations, which are the result of natural selection. No one, not even Myers, disputes that certain traits are adaptations. It's the emphasis on selection that's the problem.
The second sentence in the Dawkins quote is typical of the overstatement inherent in adaptationist thinking: how does he know that natural selection is the only explanation for the phenomena he mentioned? As Myers points out, there are many non-selective processes involved in species evolution, so by definition there are more explanations for features in biology than natural selection.
What it is is a tautology: Natural selection is important in terms of adaptations, which are the result of natural selection.
It's not a tautology, adaptive features could have been, oh, let's say magicked that way by some sort of deity. Or produced by front-loaded orthogenesis. Or Lamarkian evolution.
The second sentence in the Dawkins quote is typical of the overstatement inherent in adaptationist thinking: how does he know that natural selection is the only explanation for the phenomena he mentioned?
Well, that which is functional will in fact be favored by natural selection over that which is less functional.
adaptive features could have been, oh, let's say magicked that way by some sort of deity. Or produced by front-loaded orthogenesis. Or Lamarkian evolution.
Um, but no one is disputing that adaptive features are the result of natural selection. What's being refuted here is the notion that natural selection is all-important to evolution because it's responsible for adaptation. Adaptation is not synonymous with evolution.
that which is functional will in fact be favored by natural selection over that which is less functional.
Another point no one disputes. But the question I asked is, How does Dawkins know natural selection is the only explanation for the phenomena he described?
How does Dawkins know natural selection is the only explanation for the phenomena he described?
But that is not his position - it's what you claim his position is. Quite different.
Dawkins knows more about evolution than almost anybody on the planet, you can take it that he knows and understands that, for instance, genetic drift may be responsible for much of evolutionary change.
Je suis Charlie. Je suis Ahmed. Je suis Juif.
Life, don't talk to me about life - Marvin the Paranoid Android
"Science adjusts it's views based on what's observed. Faith is the denial of observation so that Belief can be preserved." - Tim Minchin, in his beat poem, Storm.
Um, but no one is disputing that adaptive features are the result of natural selection. What's being refuted here is the notion that natural selection is all-important to evolution because it's responsible for adaptation. Adaptation is not synonymous with evolution.
It really depends on what you are trying to explain. Darwin was originally trying to explain why life physically changed through time. Natural selection is the main driver of those observations.
If you are trying to explain how junk DNA in two species diverges over time, then selection is obviously not going to be as important.
Darwin was originally trying to explain why life physically changed through time. Natural selection is the main driver of those observations.
Even Darwin said "natural selection has been the main but not the exclusive means of modification," and spent the rest of his career battling misrepresentations of his theory. Contemporary biologists know a lot more about population genetics than Darwin did, and realize that natural selection has been given pride of place for many reasons aside from scientific evidence.
The notion of adaptation lends itself very easily to theorizing about what a trait or feature is "for," and the allure of this boundless horizon has led to a lot of bad thinking in a self-validating Panglossian fashion. Unfortunately, this bad thinking has also taken the form of scientific rationales for prejudices about race and gender. The idea of competition among organisms (or genes, in Dawkins's view) jibes with our Western democratic ideal of a meritocracy, the best of all possible worlds coming about not through divine fiat but individual success. Last but not least, the concept of selection satisfies the need for simplification of the staggeringly complex matter of the development of life on Earth. In Stephen Jay Gould's words:
quote:There is something immensely beguiling about strict adaptationismthe dream of an underpinning simplicity for an enormously complex and various world. If evolution were powered by a single force producing one kind of result, and if life’s long and messy history could therefore be explained by extending small and orderly increments of adaptation through the immensity of geological time, then an explanatory simplicity might descend upon evolution’s overt richness. Evolution then might become algorithmic, a surefire logical procedure, as in Daniel Dennett’s reverie. But what is wrong with messy richness, so long as we can construct an equally rich texture of satisfying explanation?
Contemporary biologists know a lot more about population genetics than Darwin did, and realize that natural selection has been given pride of place for many reasons aside from scientific evidence.
Then what is the main driver of changes in morphology through time?
The notion of adaptation lends itself very easily to theorizing about what a trait or feature is "for," and the allure of this boundless horizon has led to a lot of bad thinking in a self-validating Panglossian fashion. Unfortunately, this bad thinking has also taken the form of scientific rationales for prejudices about race and gender.
Then how do you explain the correlation between skin color (as determined by alleles) and latitude?
but no one is disputing that adaptive features are the result of natural selection.
Maybe I'm reading this wrong but isn't this exactly what Prof. M is disputing? Adaptationists insist there is a fitness value to all adaptations in your body or they wouldn't be there. This leads most adaptationists to posit selective pressures (natural selection) on the most flimsy of bases.
What Prof. M is saying, by my reading, is that having or not having a nose may be a major adaptation which helps define a species and is a major selective determinant in passing through the sieve of natural selection (fitness), but the (beautiful) angle of the bridge of his nose has little to no selective value to fitness and this adaptation merely drifts through the future population as a function of the probabilities in meiosis and fecundity.
Not all adaptations are the result of natural selection. The majority of the cosmetic features we see in a human phenome are adaptions born of mutation, have little to no selective value for fitness and increase or decrease their presence in a population by drift alone, not natural selection.
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