Pittsburgh Professors Challenge Darwin

Syberghost writes "Darwin's Theory of Evolution comes under an interesting attack from an American anthropologist and an Italian biochemist, according to an article from University of Pittsburgh's school newspaper. In a nutshell, Schwartz and Maresca argue that change is not gradual as Darwin stated, but comes rapidly in response to drastic mutations caused by shifting environmental conditions."

Comments

Pardon my ignorance but

[BitterAndDrunk]

Isn't that simply punctuated equilibrium? I'd thought it was already considered part of current evolutionary theory. I'm a neophyte so I'm probably way off; someone correct me. (and no FSM references please; they're already hack and it's under a year old)

Re:Pardon my ignorance but

[lgw]

I agree with your analysis. How is this new at all? We've know for decades that simple mutation-and-selection doesn't drive change anywhere near fast enough to account for history. The current theory as I know it as a layman is that occasional periods of rapid change are needed, and no biologist has believed in "Darwinian" evolution for generations.

I suspect these fellows have some interesting new postulate, and the Pitt News just got it wrong.

Re:Pardon my ignorance but

[the gnat]

It takes drastic environmental change to knock everyone out of that local maximum and maybe look for a new one.

I've never been clear on the distinction between P.U. and catastrophism (not in the Velikovsky sense, though). When I first learned about the fossil record, a major point was the mass extinctions that have occurred throughout history. The "Cambrian explosion" is thought to have followed the extinction of >80% of all species, where entire phyla were wiped out. Perhaps not coincidentally, all modern phyla were present in the Cambrian era. (If memory serves there were several even worse extinctions that followed.) The naive but obvious conclusion I drew from this is that massive changes in ecosystem and depopulation of niches increased the potential for adaptive radiation as organisms moved into new niches. This would also mean that more mutations might yield an increase in fitness, since what determines fitness would be so drastically different. In a stable ecosystem, in contrast, niches don't get emptied or added and hence populations stay more static.

Is this part of the modern evolutionary theory? (I am a biophysicist, but I don't know much about evolutionary theory.)

Re:Pardon my ignorance but

[gansch]

Although this is similar to punctuated equilibria, it is not appear to be identical. In punctuated equilibria, there are periods of statis with little evolution of new species, interspersed with periods of rapid speciation in many species. This theory seems to apply more to single species, in which the number of individuals with a recessive mutation reach some sort of critical mass, at which time the recessive trait manifests itself and speciation occurs.

Misleading, sensationalist headline.

[TripMaster Monkey]

The title of TFA reads, "Professor Challenges Evolution", when in fact he is doing nothing of the sort.

From TFA:

Schwartz refuted Darwin's theory of gradual evolution in organisms with one that states that evolution occurs quickly and suddenly as the result of cell mutations.

While Schwartz is challenging a specific premise of evolutionary doctrine, he is by no means refuting the entire theory. Apparently, Nan Ama Sarfo felt the story would be read more if it appeared to jump on the anti-evolution ID bandwagon.

Shame on you, Nan.

Re:Misleading, sensationalist headline.

[greginnj]

Shame on you, Nan.

Don't blame Nan, the prof set her up:

"Darwinism's presence in science is so overwhelming," Schwartz said. "For the longest time, there was no room for alternative thinking among the scientific community."

Point one, he's feeding her the extremism, she isn't including it herself. Second, his second line is complete and utter bs. As others have noted, this warm-over of punctuated equilibria is a challenge to Natural Selection as the mechanism of evolution, not to evolution itself. Doing science is always about challenging the previous order -- it's only the stuff that's new and different that even gets published.

But why is he doing this? Here's a clue:

Jeffrey Schwartz -- a Pitt professor in the department of anthropology and the department of history and philosophy of science ...

Hmm, interesting fields he's in. Just like Steve Fuller did in the Dover ID trial, some people in philosophy of science have a vested interest in creating the appearance of warring camps of ideas rather than evidence-based epistemology. To paraphrase them, 'science is about persuading people, not proving ideas'.

One more thing,Schwartz has been pushing this idea for 6 years, it's not new news even for him:

Book Review published in 7/2000

Before this devolves into an ID blast-fest ...

[MrFlibbs]

... please RTFA. All the guy is saying is that sudden changes are brought about by environmental stress creating recessive genes, and these bring about rapid changes in a population after the recessives start combining in offspring.

The only feature of classic Darwinism that he's refuting is about a single organism's offspring being the only one with the new trait. Interesting notion, but hardly revolutionary.

-1, deceptive headline

[Stoutlimb]

How much more inflammatory can one get? The article should read "Scientists debate the details of how evolution happens." Talk about being deliberately inflammatory.

Punctuated Equilibrium

[CODiNE]

As has already been posted, this is a well known theory and as far as I know what the currently accepted evolutionary model suggests.

I think the point he's making is that it's simply not being taught. I know plenty of people (especially on Slashdot) who still believe the old "millions of years of small gradual changes" bit. Natural selection and gradual modification MAKE SENSE to most people and seems fairly persuasive, but it's not really what happened. Honestly I think it's a bit of bait 'n switch... explain evolution one way to a person, then later on "Oh by the way nobody really believes that."

Re:Punctuated Equilibrium

[JohnFluxx]

And I know lots of people who still think that momentum = mass * velocity. Maybe we should write an article saying that I've proved physics wrong because schools teach it incorrectly. Or maybe we should realise that people learn things in stages - simplistic explanation first.

Poppycock

[the eric conspiracy]

The concept that the idea of rapid change is a revolutionary attack on Darwinism is poppycock.

Darwin's thesis is in two parts - that evolution occurs, and that the mechanism is natural selection. The first part is not under any scientific debate. The second part, the proposal that natural selection is the mechanism has been understood to be not the best mechanism for the process of evolution has been understood for nearly 100 years. Darwin did not understand genes, genetics, nor the mechanisms of genetic drift that occur within populations. This knowedge postdates Darwin's original work.

The understanding of evolutionary mechanism works at the level of genes, and populations whereas Darwinism was concerned mainly with species.

This view of the mechanism of evolution is widely misunderstood in the creationistic and anti-evolution communities, and ignorant articles often appear trying to discredit evolution based on a fundamental misappropriation of the topic.

It's a shame that this sort of article was published on Slashdot - it shows a great ignorance of the topic.

ID will miss the lesson

[MuNansen]

What's funny is that this article is a great example of how evolution isn't a dogma. The scientific community is constantly seeking to improve or amend it. Insteal the ID'ers (funny how close that is to "idolaters") will just use the headline "Scientists disprove Evolution."

Whether or not you consider evolution to...

[Expert Determination]

...be "gradual" or "sudden" is a function of the granularity you work at. If you take a broad overview of evolutionary history then it looks very gradual. An expert in bivalves might consider the lengthening of a shell by 2mm in a time too small to discern from the fossil record as something sudden whereas most people, in particular those studying evolution for the first time, would be entirely justified in considering the change to be gradual. So please, if you're going to argue about this, define your terms.

I wrote a reply to that effect:

[Morosoph]

Given the modern controversy over the role of natural selection, the article is misleading, and the headline is wrong.

The professor hasn't challenged evolution by natural selection, but rather gradualism, as did Steven J. Gould. Darwin did posit gradualism, so an accurate headline would have been to say that the professor had challenged Darwin. As it is, it appears that it is the theory of evolution, rather than the detail of Charles Darwin's theories that is being challenged.

The article is to be commended upon the elucidation of the "dual mutation theory"; is it a shame that it did not make clearer that this theory restores natural selection to the driving seat.

This is important, since responsible editing that promotes truth over political advantage should seek avoid false inferences from being drawn by the less sophisticated.

Faithfully,

Not a challenge at all

[955301]

Please, stop with the sensationalism.

All this means is that the size of a step in a particular direction an animal can take can be large to accomodate a large environmental impulse. But most environmental changes are gradual and therefore most responses are as well. Otherwise there would be big oscillations, e.g., an ostrich has a parakeet which has a penguin, etc.

Control system 101. The guy just thinks the steps can be greater than we imagine. Makes sense since we don't get many opporunities to experience significant changes.

One tooth at a time

[gorrepati]

It is common knowledge that Darwins theory does not specifically goes into details, but gives a general framework to think evolution of organisms in. Though it is not proved, people in the community have a sense that some mutations are not gradual, and evolution does not solve some problems twice. Genetic code contains a lot of junk, but people do feel that junk has a purpose like memory about past problems. Coming to the funny part, as this guy states about evolution, fish did not ever try to grow one tooth at a time. It probably occured by hardening the jaw first, having some divisions in the jaw, having harder parts on top of the jaw(Called the tooth) and having many tooth. I seriously doubt wether this guy knows Darwins evolution at all..

Evolution of theories

[VincenzoRomano]

I think that none should trash any theory, unless there are some clear evidences and, much better, when there is one theory able to provide answers when the other ones cannot.
Evolution theory seems to be quite reasonable because it seems to rely on very few postulates when compared to other theories.
If other theories need fewer postulates and provide more answers, then chances there are that they will succeed.
I'd suggest a quick read of "The Fabric of reality" by David Deutsch for deeper details about this philosophy.
In any case theories about evolution are themselves subject to evolution whenever the objective is to provide answers.

Playing with words

[MarkusQ]

Changes in the statistics of the presence of genes in a population over time is evolution.

No, this is a meme of the anti-evolution crowd (part of the "scientists dispute evolution" nonsense) that is to often repeated by loose-thinking scientists and popularizations. You are confusing one of the intermediate effects of evolution (an effect which, as you note, could have multiple causes apart from evolution) with evolution itself. Lets see how that sort of fuzzy thinking looks like in another environment:

Changes in the statistics of the presence of the sun in a the sky over time is the heliocentric theory of the solar system.

To which, of course, you reply: No, no, no! The heliocentric theory of the solar system explains why we see the sort of pattern of sunlight that we do--it isn't just the change in sunlight, but a specific theory that predicts why we see the sort of patterns of change of sunlight that we do.

Same deal in evolution. Or to bring it on home: giraffes, bats and whales all had a reasonably recent common ancestor. There is no reason what so ever for genetic drift to have taken this common ancestor towards any of the three forms in particular. The amazing fact is, we do not find whales grazing the savanna, bats swimming in the open sea, and giraffes hanging upside down in caves. The odds against the situation we do see are already pretty steep, and when you throw in polar bears, monkeys, elephants, house cats, foxes, and so on it gets down right amazing that every population seems to have "drifted" from the common ancestor in a way that suited its environment.

Now, the genetic drift idea just leaves this hanging out there, and doesn't even attempt to offer an explanation (which is why the closet Intelligent Design people keep trying to keep it in play). But Darwin makes a bold prediction; this directed change is not the result of any magical force, but rather the effect of a simple, natural process; the change was random, but the maladapted variants died off at a faster rate than the rest. In the ocean, bat-like mutations just didn't do as well as the whale-like mutations.

There are many studies of such populations in absence of at least known natural selection factors that show evolution (changes in gene distribution statistics).

Same problem: evolution isn't just change, it's adaptive change.

While genetic drift is a stochastic process, an allele is truth state, and eventually it will propagate throughout the population, or disappear completely.

Granted. But it's a string of nonsequitors.

The power of genetic drift effects can be seen in a striking example in the human race - every living human has mitochondrial DNA originating from a single female. There are many other examples of human populations (where natural selection is generally not a factor) that for one reason or another are genetically isolated and are quite divergent in their genetic statistics.

This is another Intelligent Design meme: that some how, humans are magically out of reach of natural selection now. It is completely unfounded--unless you are claiming that something like "everyone has exactly the same number of children" or "people's inherited characteristics have no effect on their breeding success", you'll see it as soon as you stop to think about it.

But in any case, even if it wasn't begging the question, why should we be the least bit surprised about the mitochondrail DNA?

The evidence is pretty clear that genetic drift is an important cause of evolution. Some feel it is more important than natural selection.

The evidence is smoke and mirrors and the people who have been taken in by it either 1) have an agenda or 2) aren't thinking very clearly. You can trot out all the "experts" that you want, but if an idea doesn't hold water (or, as in this case, needs a supernatural entity to care the w

Re:Playing with words

[MarkusQ]

evolution isn't just change, it's adaptive change.

Sorry, that is just not correct. Evolution is NOT defined in modern biology as adaptive change. Your basic premise is wrong, making your arguments specious.

Funny, I feel the same way about your argument. A quick google shows about a 50/50 split in the definitions which specify "adaptive change" (in some form or another) as opposed to the ones such as you site. To give just a few examples:

• a process in which something passes by degrees to a different stage (especially a more advanced or mature stage)
• The change in life over time by adaptation, variation, over-reproduction, and differential survival/reproduction, a process referred to by Charles Darwin and Alfred Wallace as natural selection.
• The long-term process through which a population of organisms accumulates genetic changes that enable its members to successfully adapt to environmental conditions and to better exploit food resources
• In Darwinian terms a gradual change in phenotypic frequencies in a population that results in individuals with improved reproductive success.

But, as I pointed out, this isn't a problem that can be solved with dueling citations; even starting down that path misses the fundamental point that genetic drift alone can't explain any of the key observations about life:

• It is very diverse
• The diversity is (to a good first approximation) perfectly adaptive
• When you drill down to a more detailed accounting it is still adaptive, but at the level of genes, not individuals or populations (e.g. see Dawkins "Extended Phenotype")
• It is optimal, in the sense that permuting the diversity in any way (e.g. hanging giraffes from cave roofs) would destroy one or more of the points above.

So if you define "evolution" as above, you wind up faced with the fact (from your source) that "Drift produces evolutionary change, but there is no guarantee that the new population will be more fit than the original one. Evolution by drift is aimless, not adaptive." and you have done nothing but muddy the waters. By calling every change "evolution" you admit more causes which can do nothing to explain anything that needed explaining.

For example, suppose a new school of "economic biologists" broadened the definition of evolution still further, to include (say) a change in the average market value of a member of the species or the number of books in which it is mentioned. What good would that do? Now there would be a whole bunch more things that could cause "evolution" but they would have done nothing to clarify the question--instead, they would have confused things horribly.

And that, pretty much, is what "population genetics" has done. The questions are murky enough at the level of the individual organisms, but by considering populations you effectively average out all the interesting questions and wind up making vacuous statements such as "genetic drift causes evolution" where "genetic drift" is defined (again from your source) as what happens when, by chance "the frequency of an allele may begin to drift toward higher or lower values."

Combining this with your definition of evolution, we have:

The frequency of an allele drifting toward higher or lower values causes changes in the statistics of the presence of genes in a population over time.

Which, as I hope you can see, has no explanatory value whatsoever and makes no testable predictions to speak of (though the converse would be world shaking news).

--MarkusQ