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.
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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,"
Never mind.
Need to read more thoroughly instead of stopping on certain 'points'.
:0(
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. :-)
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