Skip to comments.Pitt Professor's Theory of Evolution Gets Boost From Cell Research [Sudden Origins]
Posted on 01/26/2006 11:47:13 AM PST by PatrickHenry
Jeffrey H. Schwartz's Sudden Origins closed Darwin's gaps; cell biology explains how.
An article by University of Pittsburgh Professor of Anthropology Jeffrey H. Schwartz and University of Salerno Professor of Biochemistry Bruno Maresca, to be published Jan. 30 in the New Anatomist journal, shows that the emerging understanding of cell structure lends strong support to Schwartz's theory of evolution, originally explained in his seminal work, Sudden Origins: Fossils, Genes, and the Emergence of Species (John Wiley & Sons, 2000).
In that book, Schwartz hearkens back to earlier theories that suggest that the Darwinian model of evolution as continual and gradual adaptation to the environment glosses over gaps in the fossil record by assuming the intervening fossils simply have not been found yet. Rather, Schwartz argues, they have not been found because they don't exist, since evolution is not necessarily gradual but often sudden, dramatic expressions of change that began on the cellular level because of radical environmental stressors-like extreme heat, cold, or crowding-years earlier.
Determining the mechanism that causes those delayed expressions of change is Schwartz's major contribution to the evolution of the theory of evolution. The mechanism, the authors explain, is this: Environmental upheaval causes genes to mutate, and those altered genes remain in a recessive state, spreading silently through the population until offspring appear with two copies of the new mutation and change suddenly, seemingly appearing out of thin air. Those changes may be significant and beneficial (like teeth or limbs) or, more likely, kill the organism.
Why does it take an environmental drama to cause mutations? Why don't cells subtly and constantly change in small ways over time, as Darwin suggests?
Cell biologists know the answer: Cells don't like to change and don't do so easily. As Schwartz and Maresca explain: Cells in their ordinary states have suites of molecules- various kinds of proteins-whose jobs are to eliminate error that might get introduced and derail the functioning of their cell. For instance, some proteins work to keep the cell membrane intact. Other proteins act as chaperones, bringing molecules to their proper locations in the cell, and so on. In short, with that kind of protection from change, it is very difficult for mutations, of whatever kind, to gain a foothold. But extreme stress pushes cells beyond their capacity to produce protective proteins, and then mutation can occur.
This revelation has enormous implications for the notion that organisms routinely change to adapt to the environment. Actually, Schwartz argues, it is the environment that knocks them off their equilibrium and as likely ultimately kills them as changes them. And so they are being rocked by the environment, not adapting to it.
The article's conclusions also have important implications for the notion of fixing the environment to protect endangered species. While it is indeed the environment causing the mutation, the resulting organism is in an altogether different environment by the time the novelty finally escapes its recessive state and expresses itself.
You just can't do a quick fix on the environment to prevent extinction because the cause of the mutation occurred some time in the past, and you don't know what the cause of the stress was at that time, Schwartz said.
This new understanding of how organisms change provides us with an opportunity to forestall the damage we might cause by unthinking disruption of the environment, added Schwartz. The Sudden Origins theory, buttressed by modern cell biology, underscores the need to preserve the environment-not only to enhance life today, but to protect life generations from now.
Schwartz, with his colleague Ian Tattersall, curator of anthropology at the American Museum of Natural History in New York, also authored the four-volume The Human Fossil Record (Wiley-Liss, 2002-05). Together, the volumes represent the first study of the entire human fossil record. Volume 1 was recognized by the Association of American Publishers with its Professional Scholarly Publishing Award. In 1987, Schwartz's The Red Ape: Orang-utans and Human Origin (Houghton Mifflin Company) was met with critical acclaim.
Schwartz, who also is a Pitt professor of the history and philosophy of science, was named a fellow in Pitt's Center for the Philosophy of Science and a fellow of the prestigious World Academy of Arts and Science.
The journal, The New Anatomist, is an invitation-only supplement to the Anatomical Record.
Has a lot to recommend it, as an adjunct to evolution.
My question is, why would cells 'suddenly' change instead of a gradual change over time, as Darwin suggested?
Sudden climatic change?
Only if the goal is to protect the current set of species. If the goal is to encurage species change, then environmental changes are a good thing.
This sentence is merely a bone to the environmental lobby, the authors no doubt hoping to get a few bucks thrown their way. Such raw pandering to the political left is why many conservatives don't trust science.
"Environmental upheaval causes genes to mutate,"
Need to read more thoroughly instead of stopping on certain 'points'.
The answer's in the article. Stress causes mutations, which are often recessive. But some time after the mutation, and the recessive gene is propagated through the population, it becomes more likely to double up and become the expressed gene in an individual, rather than the old dominant gene.
Were evolution driven randomly, there would be sudden emergences on all time scales. WTP?
Lots of neutral mutations occur, and they don't get selected in or out. They just persevere in the gene pool. Every now and then, a change in the environment makes such mutations advantageous to have. If they didn't exist, the species might go extinct -- most of them do. But sometimes, some of them may possess just the right characteristics (previously neutral mutations) for continued survival.
"Rather, Schwartz argues, they have not been found because they don't exist, since evolution is not necessarily gradual but often sudden, dramatic expressions of change"
Someone on another thread today was trying to explain to me that evolution was gradual and now this guy says it's often sudden. And you wonder why people have a hard time accepting TOE.
Ah, but evolution isn't driven randomly. Billions of mutations are happening all the time, most of them either harmful (they get washed out) or neutral (they're ignored). Given that raw material to work with, the changing environment rather ruthlessly filters out whatever isn't right for the time. And that's not random. It can be modeled, with great advantage.
Specific examples of Genetic Algorithms. Practical applications galore!
Looks like the soft sciences (biology, genetics, etc.) are taking over from the hard sciences (paleontology, geology, etc.).
At least paleontologists, geologists and archaeologists aren't afraid of getting their hands dirty!
> Someone on another thread today was trying to explain to me that evolution was gradual and now this guy says it's often sudden.
Yes? There's no conflict here. Gradual change with occasional leaps. This is only a problem for those who refuse to recognize that nature tends to be a tad chaotic.
Biology isn't a soft science. Just squishy. It's not as austere as physics and astronomy, but I regard it as one of the "hard sciences."
Biology! Bah! Those folks never even leave the lab. Bunch of softies.
Now archaeology, that a hard science. Can't tell you how many rattlers I have had to kick off the trails (they're pretty good sauteed in white wine, a little olive oil, etc.--but the little ones are way too bony).
Maybe the cancer analogy is more apt than you think. Perhaps cancer is one form, albeit a lethal one, of expression of such 'new' genes. Two paths are present - one that leads to new adaptation, the other to illness and frailty. Then, obviously, the adaptable form will persist. The cancer forms are just dead ends. So the mutation occurs at one point in time, then at some future point, it becomes manifestly dominant under the pertinent situation.
Maybe I am missing something here, but is this guy suggesting that environmental factors cause not just one gene to alter in the DNA of one cell but the same gene to alter in every cell in an organism at the same time and in the same way to the extent that even new reproductive cells that pass on genetic information to the offspring duplicate the mutation? Moreover, is he suggesting that these genetic mutations, which have taken place in every cell of the organism and even in future reproductive cells, are duplicated in other similar organism to the extent that when two of these organism that have indipentently undergone the same genetic mutation mate, the genetic mutations are passed on into the genetic pool as viable genetic variants? Natural selection I understand. This, on the other hand, is LAUGHABLE!!!!
You know that environmental factor? His name is GOD.
This guy's going to have a hard time getting his theory accepted if he calls it "sudden origins theory". But it may catch on in creationist circles. :-)
Certainly, Molecular Biology is a pretty 'hard' science.
Wonder how much grant money is involved?
Heck, I do well to add and subtract! :)
Agreed. Alas for Jeffrey H. Schwartz, the creationists and ID-ers have pretty much already reserved that term for the next incarnation of their hocus-pocus. He'd be well advised to call it something like "latent characteristics" or something.
Hard? You ever see a molecular biologist at work with dirt under his/her fingernails? Worse problem they probably have to cope with is the air conditioning set too high.
That's right. Some of us really throw ourselves into our work!
It's a crappy job, but someone has to do it! :)
That would seem to open gaps in the Natural Selection areas in evolution, rather than close them. If the changes are due to an ice age, and don't show up for a long time after, then it would have double the trouble of being viable.
The guy made a nice try, but as Casey learned, even a mighty swing can miss the ball.
this thread has gone to sh--
Interesting theory. Has nothing to do with Darwin, however.
No, he's not, and yes, you are missing something.
Moreover, is he suggesting that these genetic mutations, which have taken place in every cell of the organism and even in future reproductive cells,
are duplicated in other similar organism to the extent that when two of these organism that have indipentently undergone the same genetic mutation mate, the genetic mutations are passed on into the genetic pool as viable genetic variants?
That's not how new mutations get spread through the population. The old "a new mutation would need an identical mutation to mate with" canard exists only in creationist pamphlets, and bears no resemblance to how things actually work in biology.
Natural selection I understand.
Somehow I doubt that.
This, on the other hand, is LAUGHABLE!!!!
Not at all, although your misunderstanding of the article, and of biology in general, is rather amusing.
You know that environmental factor? His name is GOD.
No, not unless you call environmental stressors "God". See for example: Bradshaw, A.D. (1965). "Evolutionary significance of phenotypic plasticity in plants," Advances in Genetics vol 13 pp 115-155, [West-Eberhard, M.J. (1986) "Alternative adaptations, speciation, and phylogeny (A Review)," Proceedings National Academy of Science USA vol 83 pp 1388-1392] [Harrison R.G. (1980) "Dispersal polymorphisms in insects," Annual Reviews of Ecological Systems vol 11 pp 152-153.] [Schlichting, C.D. (1986) "The evolution of phenotypic plasticity in plants," Annual Review of Ecological Systems, vol. 17 pp 667-693] [Stearns S.C. (1989) "The evolutionary significance of phenotypic plasticity" Bioscience vol 39 pp 436-445].
LOL! Dirt under the finger-nails is not the definition of hard science, unless car mechanics are scientists. Scrabbling around in the dirt might be fun, but it ain't Physics.
You've claimed I am wrong but you have not explained how these things could possibly be true. How could these mutated genes be passed on as recessive genes as the author claims unless they entered the genetic information of reproductive cells? If I am missing something, please, explain it to me.
P.S. Unlike you, I have never read creationist literature. This is pure logical analysis and evolution has never added up in my book.
Of course they don't exist.
How can evolutionists claim their 'theory' is a fact when they can't even decide if change was gradual or sudden?
This article is nothing more than wild speculation presented in an attempt to overcome the obvious weaknesses of the many theories of evolution speculated about by others.
If anything, this article casts further doubt on evolution.
Environmental stress isn't the only factor in natural selection. Sexual selection is well-recognized. Environmental stress is one of the causes of mutation, but not the only cause.
And the great hypocrisy of promoting environmental stasis in the name of maximizing the gene pool and species diversity.
Because, like *all* inheritable mutations, they first occurred *in* reproductive cells. This is such basic biology that the article didn't bother to spell it out -- it would be like an article on a new airplane design not bothering to mention that aircraft need an atmosphere to fly and don't work in a vacuum.
Nothing in the article suggests the strange scenario you described, involving all the cells in a body mutating simultaneously. That such mutations must take place in germ cell lines is a "given".
If I am missing something, please, explain it to me.
P.S. Unlike you, I have never read creationist literature.
Then it's odd that your argument is a direct repetition of one of their standard canards. If you haven't read creationist sources, you've picked up their arguments indirectly.
This is pure logical analysis and evolution has never added up in my book.
If it were "pure logical analysis", it would not contain such elementary fallacies. For a description of how new mutations enter the population and eventually lead to speciation without there ever being a point where an individual has a problem mating with the members of the population to which he/she belongs, see this.
You might also try this. Not as authoritative as Ichneumon, but it's readable.
How can you claim to have anything of value to add to these discussions if, after all this time, you're *still* unclear on the distinction between the fact of evolution and the theories about how it proceeds in specific instances?
Hint: Evolution is slow in some instances, not so slow in others, depending on the circumstances. This article addresses some particular types of circumstances which affect the tempo and mode of evolutionary change. There's no contradiction with prior research.
This article is nothing more than wild speculation
It's based on a great deal of work, which puts it far beyond "wild speculation". It may or may not turn out to hold water when further investigated, but your desperate creationist habit of trying to hand-wave away all research and considered conclusions based on a thorough examination of the real-world evidence as "nothing more than wild speculation" just makes you guys look goofy. Sorry, but "wild speculation" is what *creationists* do when they make up things based on their total ignorance of actual biology and then mistake their presumptions for established facts. For example, like *you* did here when you made wildly incorrect assumptions about how biology "must" work... Now *that* was "wild speculation"!
presented in an attempt to overcome the obvious weaknesses of the many theories of evolution speculated about by others.
And what exactly would those "obvious weaknesses" be? Be specific, let's see if you have any clue what you're talking about. Be sure not to repeat any of these other long debunked creationist canards about the "weaknesses" in evolutionary biology.
If anything, this article casts further doubt on evolution.
It doesn't, but your post casts further doubt on your ability to keep up with technical discussions.
I like the idea of mutations remaining recessive over time until drift makes them co-recessive at which point the trait gets expressed; but I don't think a saltation event even in this scenario would be likely to have a high survival index. I suspect this is more like what happens with segmentation where a simple mutation on a HOX gene can confuse enzyme production resulting in multiple segments. Or multiple wings for that matter.
Interesting when viewed together with gene duplication followed by a partial-gene mutation on the regulatory gene.
BTW, my mind is a toaster right now, so don't blame me if'n I'm incoherent.
True, but randomly occuring mutations (random with respect to the selection function) will yield a system that moves with jumps of all sizes.
There is also the genotype-phenotype relationship. It may take several small changes in genotype to make any change at all in phenotype. Likewise, some small genotypical changes may result in large phenotypical change.
I think that "random" here would be shorthand for "mutation not necessarily related to selection."
Dear Lady, don't get the idea this concept is saying a large scale saltational event is occurring, it is more like a slow 'partially or totally hidden' bit of evolution occurring before its relatively sudden expression.
If this mechanism, or process if you prefer, is the active process in a population... oh, evolving legs let's say, the legs would not end up being full blown legs like yours or mine, but simply a larger scale 'change' to existing features, such as fins, than we would normally expect, or it could result in 'leg buds' where an existing skeletal feature is replicated in another place or modified in place - such as an additional segment of bone is added. For true legs to result from these 'buds' it would still take hundreds of generations. Remember what geological time really means.
Neither do farmers.
Don't ask me, I don't know...
2x2=4 4x4=8 8x8=16 16x16=....
Well I only 'stinct' a little.
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