Darwin: The Evolution Revolution is currently on at the Royal Ontario Museum (until August 4, 2008). There was a review of the exhibit by Peter Calamai in yesterday's Toronto Star [Darwin still battling creationists]. It seems like an excellent review. I haven't yet seen the exhibit so I can't comment on the details but everything that Peter Calamai says rings true. One of the criticisms of the exhibit is that there are too many things to read. Calamai estimates that it would take five hours to read all the explanatory panels. Another criticism is that the written information tilts heavily toward defending Darwin's ideas, and that sometimes this zeal trumps the truth ...
For make no mistake about it, parts of "Darwin: The Evolution Revolution" are an exercise in anti-creationist persuasion, usually subtle but often blatant.Calamai makes a good point. The statement on the exhibit is clearly incorrect and that's embarrassing.
Take this statement from a panel headed "Creationism" at the close of the exhibit:
"For 150 years since the publication of Darwin's Origin of Species, the theory of evolution by natural selection has not been seriously challenged by any other scientific explanation."
The weasel word here is "seriously," since that's very much a qualitative judgment. Yet, even setting Creationism aside, well-respected historians of science such as Peter Bowler (The Non-Darwinian Revolution) have maintained that alternate scientific theories of evolution, such as mutation and Lamarckism, were resolutely championed by mainstream scientists until after World War I.
Evolution through the mechanism of natural selection, the core of Darwin's approach, was simply not a "slam-dunk" scientific revolution after On the Origin of Species was published in 1859, as the ROM exhibit repeatedly implies.
Yet Darwin's thesis is widely accepted by today's scientific community. So why all the defensive proselytizing, as though his ideas were under siege?
Why is there such an emphasis on defending Darwin when such a defense is serious overkill in Canada?
Because they are – at least in the United States, where this "show-in-a-box" originates. ROM officials acknowledge that they had minimal input on the thematic level to the travelling exhibit from the American Museum of Natural History in New York.Finally, I'm glad that Peter Calamai closed his article by mentioning the problem of funding.
Where evolution is concerned, a chasm yawns between the U.S. and Canada. Polling by Angus Reid published two years ago found that one in five Canadians surveyed agreed with the statement that God created human beings in their present form within the last 10,000 years. Nearly half the Americans surveyed chose this option.
The resulting anti-creationist mindset, while at times annoying, cannot ruin an exhibit that will reward multiple visits at several different levels.
Perhaps we haven't progressed as far from such times as we'd like to believe. The Darwin exhibit opened without an outside sponsor, although several groups have since rallied to the cause, including the Humanist Association of Canada.I know the members of the Humanist group who put up the money. Thank
But there's still no major corporate sponsor. They're all too spooked by the prospect of the one-in-five minority of Canadians who believe – despite an Everest of evidence to the contrary – that human beings sprang upon the Earth in their current form a mere 10,000 years ago.
Is it true that some of these potential sponsors have declined because evolution is too controversial? Yes, in some cases that's true. There are members of the Gairdiner family, for example, who have doubts about evolution.
There's a sentence in the Star's review that gives me pause:
ReplyDelete[Historians of science] have maintained that alternate scientific theories of evolution, such as mutation and Lamarckism, were resolutely championed by mainstream scientists until after World War I.
"Mutation" was an alternative theory to Darwin's that is no longer seriously championed? That seems to be the meaning, especially with the implied equation to Lamarckism.
Wouldn't it be more correct to say that mutation is an agent causing variation (upon which natural selection and other factors act) that was unknown to, but not contradicted by, Darwin's version of evolutionary theory?
@Jud
ReplyDeleteActually, if you go back and read turn-of-the-20th-century writings, you'll find that many scientists actually found Mendelian genetics (i.e., studying the inheritance of mutations and natural variants) irreconcilable with Darwinian selection. Fisher's The Genetical Theory of Natural Selection, 1930, is often credited with being the final nail in the coffin leading to the synthesis of genetics and evolutionary biology.
As an aside, there's some validity to the statement:
For 150 years since the publication of Darwin's Origin of Species, the theory of evolution by natural selection has not been seriously challenged by any other scientific explanation.
The only scientific explanation would have been Lamarckism, I suppose. However, Lamarckism was on a steady decline since the publication of Origin, and while some notable individuals held out until the ~1930s, it's pretty safe to say that it was never a serious challenge.
Mind you, such broad sweeping statements practically invite criticism, and thus I agree that it was probably a poor choice.
"Mutation" was an alternative theory to Darwin's that is no longer seriously championed?
ReplyDeleteI think that he is referring to the "hopeful monster" theory of evolution, which, as I understand it, was fairly widely accepted in the early 20th century.
I know Gould argued that Goldschmidt has been caricatured and that his model was more accurate than is usually claimed, but whether that's true or not I think its general reading was as an alternative to Darwin.
@iayork
ReplyDeleteI think that at that point, one would have to be careful about how one defines 'Darwinism'. I believe that Goldschmidt's work is more of an alternative to anagenic gradualism rather than natural selection and evolution as a whole (Goldschmidt himself did argue that his position was against 'neo-Darwinian' theory), according to the back of his book, The Material Basis of Evolution.
However, it's a fair assessment that the 'hopeful monster' theory was an alternative, given that Darwin did view strict gradualism as a necessary feature of his theory. However, very few scientists took/take it seriously, and thus it couldn't really be proposed as a 'serious alternative' to Darwinian evolution.
I had the chance to see this exhibit last weekend.
ReplyDeleteI agree that there was quite a lot of text to read, but I don't think it took away from the exhibit as a whole. Some of the text was in the form of written documents (facsimiles) so showing them was more of a historical curiosity. To balance out all the reading, there were several video stations, interactive computer displays, models of fossils that could be touched, the (mostly) live animals, and the recreation of Darwin's study (which was roped off).
The defense against creationism wasn't obvious to me until the end of the tour. Earlier on, they made many references to Darwin's roots in the clergy. They had some plaques discussing creationism and included intelligent design creationism in the mix. There was a video of prominent figures like Ken Miller, Francis Collins, Eugenie Scott, Niles Eldridge, etc. discussing the relevance of Darwin's theory and evolution in general.
My overall impression was that it was well done, and included a mix of media to keep the mind and the eye occupied. I was happy to see many children going through. I could have done without the gift shop at the end, but in light of the funding issues for the exhibit I don't blame them.
Oh ya, the Dinosaur exhibit on the second floor is awesome! If you're going to the ROM, the Dinos are a MUST SEE.
"'Mutation' was an alternative theory to Darwin's that is no longer seriously championed?"
ReplyDeletePerhaps they are referring to transmutation or saltations, which is the sudden emergence of a new feature or a sudden change from one defined "type" into another "type".
I don't think the article is referring to mutation like we think of it today, ie mutations in DNA.
It does seem like the article is making a broad claim about Darwin's theory being accepted from the get-go, which is inaccurate. Wasn't the period after WWI when Darwin's theory became largely accepted known as "the great synthesis" or some such thing?
Perhaps they are referring to transmutation or saltations
ReplyDeleteChris (or Larry), is that different from the "hopeful monster" concept? I had thought they were the same thing, but I think that's just based on the name.
Carlo, I think that in some of Mayr's books he says, or at least implies, that the hopeful monster/saltation concepts were the dominant theory in the early 1900s. Am I misremembering, or otherwise confused? Do you have any sense of how well accepted the various concepts were in that period (say, 1910-1930-ish)?
I had the chance to see this exhibit last weekend.
I went to it in early April, via a special trip to Toronto (the fact that the Red Sox were playing the Blue Jays that week had nothing to do with it, really). (http://www.iayork.com/MysteryRays/2008/04/09/darwin/)
I thought it was well done, with a good balance between targeting people off the street, and those seriously interested in the subject. I had my kids (4 and 7 years) there, and they found it moderately interesting -- the 7 year old picked up some of the concepts and asked lots of questions, so it worked to that extent.
jud asks,
ReplyDelete"Mutation" was an alternative theory to Darwin's that is no longer seriously championed? That seems to be the meaning, especially with the implied equation to Lamarckism.
Wouldn't it be more correct to say that mutation is an agent causing variation (upon which natural selection and other factors act) that was unknown to, but not contradicted by, Darwin's version of evolutionary theory?
He's referring to mutationism. This is the idea that evolution is primarily determined by mutation and not by natural selection on existing variation. This was the view held by scientists like Thomas Hunt Morgan, Hugo de Vries, and William Bateson.
You can read about it in my essay Evolution by Accident. The modern version of mutationism is gaining in popularity. I'm one of those people who think it deserves a lot more credit that it currently receives.
Here's a quotation from the Wikipedia article on mutationism.
At the time of the Darwin centennial in Cambridge in 1909, Mutationism and Lamarckism were contrasted with Darwin's “Natural Selection” as competing ideas; 50 years later, at the University of Chicago centennial of the publication of The Origin of Species[1], mutationism (like Lamarckism) was no longer seriously considered. However, with the arrival of molecular biology, some scientists proposed that mutational pressure was the basic process of evolution [2] [3], a view that Nei has referred to as "neo-mutationism"
Nei, is Masatoshi Nei. It's his modern view of mutationism that is going to change our perspective on evolution, in my opinion.
The hegemony of neodarwinism is fading, if anything: juts how importnat and explicative natural selection really is still lively discussed. The "malthusian" notion of progressist natural selection defended by Darwin is probably simply false, despite its enduring popularity among amateurs and right-wing economists.
ReplyDeleteBoth mutationism and lamarckism have experienced "revivals".
In fact, many of the ridiculed claims of lamarckists were correct, such as the experiments with daphnia (see Agrawal 1999). The verbal description of "inheritance of an acquired caracteristic" used in the 20's and 30's is simply a different verbal description for the same kid of phenomenon that thereafter Waddinton would have to rechristen "genetic assimilation" This did not succeed in making it more palatable to neodarwinians, who ignored waddington and continued simply continued with a truly stupid and frivolous knee-jerk demonization as a reaction to lamarckism. Same thing with Goldschmidt (who was a truly great scientist)
When Darwin wrote The Origin of Species, he had no mechanism by which the variation required by his hypothesis could be generated; however, it was obvious that it did exist. The explanatory power of selection with regards to adaptation was so powerful that a form of extreme 'selectionism' emerged, and still finds adherents to this day.
ReplyDeleteI read your essay Dr. Moran and found it quite interesting - I've come to the same conclusions based on my own reading and graduate work.
I think that what you and Sanders are pointing out is the death-grip that some evolutionary biologists are holding out against a proper acceptance of contingency and stochastic processes that must underlie the basic foundation of evolutionary principles. I've read several speculative papers that continue to make selectionist claims without an appropriate test to reject simple neutral models of change - a biological concept that's been rigorously tested time and time again, only to pass muster.
From speaking to several colleagues, it can still be challenging to publish papers exploring punctuational concepts (such as the possibility of rapid genetic divergence immediately following speciation, when population sizes are small and subject to stronger random evolutionary 'forces').
However, with the exception of Lamarckism, I'm not sure that these alternative theories were really incompatible with Darwinian theory, or 'alternative theories of evolution' (mutationism is an alternative view of how variation is generated and made available to selection). They strike me more as examples of the natural, scientifically healthy 'controversies' that persist in the field.
No comment that one of the exhibit patrons is the (United Church of Canada) Observer? :-)
ReplyDeleteNo, Darwin was lamarckian, too.
ReplyDeleteThe biggest problem with Lamarckism is that it was adaptationist. With a progressist touch, too.
In the facts, whether a trait is adaptive or not is not fundamental as to whether it can go from environmentally induced, to genetically induced.
About natural selection; ask any fan of dawkins if he thinks it is a satisfactory explanation to how the vertebrate eye or the mammalian middle ear evolved. They will say yes.
But anyone that has studied closely how a complex structure evolves will come to a very different conclusion. Exaptation is crucial. From bacterial flagellum to middle ear. All this insight is lost with the "satisfactory" answer of simply pointing to the structure and saying "NS did it". It's a much more ideological than structural explanation.
Consider this. How does NS help us to understand how did bones that were connecting the jaw to the skull, ended up in the middle ear?How did the ancestors of mammals manage to move those bones, and still be able to bite and chew functionally?
What insight does population genetics give us on this issue?
Is saying "it was natural selection and gene change in the population" a truly satisfactory answer to this question?
Now, the question does indeed have a TRUE, non-ideological answer, which is well documented in the fossil record (the double-jaw articulation)
No, Darwin was lamarckian, too.
ReplyDeleteNo he was not. Lamarckism is not simply 'Inheritance of acquired characters'. People are in the habit of forgetting the whole 'Individuals lose characteristics they do not require (or use) and develop characteristics that are useful.' If an organism cannot hear, how can it strive to use its hearing until it resolutely develops the apparatus for hearing itself?
Back to the inheritance of acquired characters, how is exaptation Lamarckian? It does not require that characters acquired during an organism's lifetime be passed on to its descendants, but rather that existing structures and genetic variation be selected upon in order to produce novel phenotypes. Feathers used as insulators that were exapted for flight need not be passed on by parents who strove harder to fly - those whose existing genetics variation that predisposed them to remain aloft longer, on average, tended to leave more offspring.
Maybe I'm not following your meaning but I don't understand how this requires Lamarckism.
I was just making a point of the ideological use of the notion of natural selection. Separate that bit form my comment on lamarckims. PLease: I am NOT relating exapation to alamrckism.
ReplyDeleteYou said that lamarckism is incompatible with darwinism. This is a well-repeated mantra. All I'm doing is reminding you that darwin adscribed to the inheritance of acquired trait. Plus, as I pointed out, both darwinism and lamarckism are adaptationist and progressist. Thus, perhaps not so incompatible a as you may think.
"exaptation (requires) that existing structures and genetic variation be selected upon in order to produce novel phenotypes"
ReplyDeleteNo. In fact it susually requires a non-adaptive structural "spandrel". You took it back to selection right away...no, man. That's not what expataion is about. If you study the term a bit closer you will find that non-adpative spandrels, a phenomenon totally unexplained by natural selection, is often fundamental to exaptation. Second, exaptation is not simply stating that some tructure comes from the modification of a previous one (that is just homology). Exapataion implies a SHIFT IN FUNCCTION that, again, has NOTHING TO DO with NS; it's lie saying that if I can hold a window open with a scfewdriver, that's a wonderful example of NS.
Read what Gould has to say about the logic of expatation (redundancy of structure, roverlap of function). It's simply a totally different game than NS.
@Sanders
ReplyDeleteI have no idea what you're talking about, and I've read at least 10 of Gould's books, including the first seven in his collected essay series. According to evolution 101 at UC Berkeley:
* Exaptation—a feature that performs a function but that was not produced by natural selection for its current use. Perhaps the feature was produced by natural selection for a function other than the one it currently performs and was then co-opted for its current function. For example, feathers might have originally arisen in the context of selection for insulation, and only later were they co-opted for flight. In this case, the general form of feathers is an adaptation for insulation and an exaptation for flight.
The feature that has been co-opted may have arisen by neutral processes or via selection, but nothing about this contradicts the statement that exaptation co-opts existing structures and genetic variation, irrespective of how they arose. There is nothing about this that is contradictory to modern evolutionary theory - modern Darwinian theory takes into account both selective and neutral processes in shaping genotypic and phenotypic variation.
If your only point was that exaptation can work on non-adaptive structures, then I agree. But there's nothing about this that's somehow a major revolution among modern evolutionary theorists.
"a feature that performs a function but that was not produced by natural selection for its current use"
ReplyDeleteAlos read "eight little piggie", the essay aboiut fish lungs,be cuase its obiocu you don't understand what I said about redundant structures and functional overlap.
Is this incosistent with natural selection? No. Natural selection is incosistent with nothing (whihc is one of the problems with its inapproaite reification as "central" mechansim of evolution)
Is it simply natural selection? Nope. But as long as people feel sooo satisfied with selective explantion, they will tend to ignore that.
Larry, et al., I'm sorry that I missed this discussion! I have had numerous discussions on the status of mutationism, all of them failures.
ReplyDeleteEveryone today is familiar with certain historical facts, namely that mutationism (and indeed, genetics) was understood as contrary to Darwin, and that mutationism was opposed by the architects of the "Modern Synthesis".
The problem, in my experience, is that some people refuse to accept the scientific reasons for these historical facts, even when they are easy to establish by reading the works of the scientists involved.
The first key issue is why mutationism or "Mendelism" was understood as a contradiction to Darwin's view. The answer is clear from reading Darwin and the founders of genetics, which every scientist did a century ago. The answer is NOT that Mendelism denied the principle of selection (a myth promoted by Ernst Mayr et al), but that Darwin denied mutation. Darwin knew that mutants or "sports" arise in nature, and that they sometimes have heritable effects. But he denied them any important role in evolution. In Darwin's view, change is gradual. He said explicitly that evolution did not begin with the abrupt appearance of a lone mutant (which, in his view, would be deleterious, and whose effects would be diluted by "blending"). Instead, he invoked a mass-action process of "fluctuation" induced by "altered conditions of life", a process that can act in many individuals at once, generating abundant "infinitesimal" modifications in all features.
Importantly, Darwin's fluctuation-selection process (a.k.a. "Natural Selection") was not just gradual, but automatic: whenever the old adaptive status quo is disrupted by "altered conditions", infinitesimal fluctuations emerge, and selection results in a new adaptive status quo. This is why everyone saw Darwin's theory as something incredibly clever-- it provides a mechanism for automatic adaptation!
The mutationist conception of evolution, by contrast, does allow evolution to begin with a single discrete event of mutation. Because of this, the process of evolution was no longer seen as a deterministic process, nor even as an automatic process. The mutationists even said that a beneficial mutation was not assured of success-- it might get lost by chance!
Clearly then, genetics *did* refute Darwin's mechanism of evolution. There is no environment-induced process of "fluctuation" that produces heritable variation. The true process of origination for heritable variation, mutation, is a discrete event and it is not induced by "altered conditions of life". The mutationist view, based on genetics, was profoundly different from the view of Darwin and his followers, indeed mutationism was disturbing to those who like to find order and determinism in the universe.
Now, we come to the second issue, which is, why did the architects of the Modern Synthesis deny mutationism?
Again, all we need to do to find the answer to this question is to read what was written by the scientists involved at the time this issue was in play. The architects of the Modern Synthesis, like Darwin, simply did not accept the notion that evolution begins with a single mutation. They parodied mutationism as the "lucky mutant" view. For them "evolution" is "shifting gene frequencies" in a "gene pool" full of abundant infinitesimal variation. Just like Darwin, they said this explicitly: evolution does not begin with a new mutation. They actually redefined "evolution" as "shifting gene frequencies" and taught this as a kind of catechism to their students, in order to instill the idea that evolution begins with abundant variation and not with a new mutation. For many years, nearly every model in theoretical population genetics ignored new mutations and began instead with pre-existing variation. Its only in the past few years that mainstream evolutionary geneticists are starting to confront new mutations, and as a result, they are coming up with some bold new ideas.
If we accept the historically valid answers to these two questions, then we must see mutationism as an alternative to neo-Darwinism. Mutationist ideas are not dead, and they are receiving more and more attention all the time. The problem is that they do not get labelled correctly! Alas, we are over-run by DINOs (Darwinians-in-name-only) who have diverse views of evolution (e.g., some of them are mutationists, a few are classic neo-Darwinians) and a mixed up understanding of history, but remain steadfast in their attachment to the "neo-Darwinism" label.