Posted on 10/07/2006 9:08:18 AM PDT by PatrickHenry
Evidence for punctuated equilibrium lies in the genetic sequences of many organisms, according to a study in this week's Science. Researchers report that about a third of reconstructed phylogenetic trees of animals, plants, and fungi reveal periods of rapid molecular evolution.
"We've never really known to what extent punctuated equilibrium is a general phenomenon in speciation," said Douglas Erwin of the National Museum of Natural History in Washington, D.C., who was not involved in the study. Since its introduction by Stephen Jay Gould and Niles Eldredge in the 1970s, the theory of punctuated equilibrium -- that evolution usually proceeds slowly but is punctuated by short bursts of rapid evolution associated with speciation -- has been extremely contentious among paleontologists and evolutionary biologists.
While most studies of punctuated equilibrium have come from analyses of the fossil record, Mark Pagel and his colleagues at the University of Reading, UK, instead examined phylogenetic trees generated from genetic sequences of closely related organisms.
Based on the number of speciation events and the nucleotide differences between species in each tree, the researchers used a statistical test to measure the amount of nucleotide divergence likely due to gradual evolution and the amount likely due to rapid changes around the time of speciation.
They found statistically significant evidence of punctuated evolution in 30% to 35% of the phylogenetic trees they examined. The remaining trees showed only evidence of gradual evolution.
Among the trees showing some evidence of punctuated equilibrium, the authors performed further tests to determine the size of the effect. They found that punctuated evolution could account for about 22% of nucleotide changes in the trees, leaving gradual evolution responsible for the other 78% of divergence between species.
Pagel and his colleagues were surprised that rapid evolution appears to contribute so much in some lineages, he said. "I would have maybe expected it to be half that much," he told The Scientist.
The researchers also found that rapid bursts of evolution appear to have occurred in many more plants and fungi than animals. Genetic alterations such as hybridization or changes in ploidy could allow rapid speciation, Pagel said, and these mechanisms are much more common in plants and fungi than in animals.
"Their result is pretty interesting, particularly the fact that they got so much more from plants and fungi than they did from animals, which I don't think most people would expect," Erwin told The Scientist.
However, it's possible that the analysis could be flawed, because the authors didn't take into account extinction rates in different phylogenetic trees when they determined the total number of speciation events, according to Douglas Futuyma of the State University of New York at Stony Brook, who was not involved in the study. But "they've got a very interesting case," he added. "I certainly think that this warrants more attention."
According to Pagel, the results suggest that other studies may have misdated some evolutionary events. Dates derived from molecular clocks assumed to have a slow, even tempo will place species divergences too far in the past, he said, since genetic change assumed to take place gradually may have happened very quickly.
"These kinds of events could really undo any notion of a molecular clock -- or at least one would have to be very careful about it," Futuyma told The Scientist.
Well known evolutionary mechanisms could account for rapid genetic change at speciation, Pagel said. Speciation often takes place when a population of organisms is isolated, which means that genetic drift in a small population or fast adaptation to a new niche could induce rapid evolutionary change.
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[Lots of links are in the original article, but not reproduced above.]
IT should be obvious to most people that punctuated equilibria is NOT science. All this theory does is try and explain that ancestry should not be discernible in the fossil record (why? Because it's not in the fossil record so they have to come up with some explanation) Some scientists think punctuated equilibria and neo-Darwinism are nearly the same. That view is mistaken. The two theories are totally different. They share only their commitment to common descent. New darwinists believed in gradual evolution through phyletic lineages. they expected to see gradual intergradations and identifiable phylogeny. But the fossil record did not display either. So what do they do? They claim the fossil record is incomplete
The punctuationists are convinced the fossil record is not that incomplete and must be taken more literally. So, they invented a theory that expects neither gradual intergradations nor identifiable phlogeny.
These two theories could hardly be more different and still be common descent. They cut straight to the center of the origins controversy.
The funny thing about this is that punctuationists say their idea is testable. They feel that gradual fossil series would refute their theory. Gould said, if morphological adaptations usually accumulate with no tendency to any rapid initial setting and stabilization, then punctuated equilibrium is wrong.
Get it?
One can refute punctuated equilibria only by providing convincing evidence that evolution has occurred. What does this say? Evolutionary descent with modification has at last descended, modified, and adapted itself right out of science.
Who are these punctuated equilibria guys? not biologists but generally paleontologists - like Stephen Gould.
In short, the whole towering theoretical enterprise of punctuated equilibria was driven by problems with the fossil record. It does not predict genetics or any other well-understood biological process. It simply constructs a theory to adapt evolutionary theory in explaining the observed fossil record.
What's really funny is that punctuated equilibria is what creationists have always said. So evolutionists are trying to steal the creationists prediction
Weinbert, an evolutionists even said "So the creationist prediction of systematic gaps in the fossil record has no value in validating the creationist model, since evolution theory makes precisely the same prediction."
But .........hmmmmmmm........who knew this even before information was accumulated about the fossil record? The fossil record broke Darwin's heart and it's still a problem for for the evolutionary illusionists today.
Excellent!
Bravo!
Take a bow!
Why should anyone be interested in your attempt to define punctuated equilibrium into something which it isn't, a rejection of evolution? Gould had utter contempt for people like you, who twisted his work and his words.
I know that's a metaphorical expression, but let's look at it in a literal sense. Tons = 4000 pounds or more. At 150-200 pounds per average scientist, that would be at least 20-30 "ID scientists". I seriously doubt there are that many in the entire world, even if you leave off "brilliant".
Don't try to counter this with that list the DI people cooked up; it was scientists who said they don't think Darwinian evolution is the whole story, and that more research is needed; that is not the same as saying they agreed with ID in any way shape or form.
Mute? Do you mean "moot?
No, actually you didn't respond to any of my remarks. I took the time out to answer you point for point and you dismissed it as a rant which I so graciously proved it wasn't.
Don't bring a comic book to an encyclopedia fight
How about "mute" and "moot"
Well, except that I didn't "write" the link, I cut and pasted what I was provided by P.K. I'll check out the link you posted here, thanks.
It's because your a heck of a nice guy, that's why.
Thanks, for whatever this is suppose to be. All I have is a box with a red X in the center. Thanks anyway.
Whatever... I highly recommend the next time you decide to debate me actually come prepared. Or better yet, just don't do it.
I cut and pasted the first link directly from Professor Kill's post. I cut and pasted the second link directly from your post. The two are very clearly different.
Is your PC playing tricks on you?
He'll probably get around to it at about the same time as he gets around to My post 291 Curiously he extols the wonders of the brilliant scientists who endorse ID, while posting evolution rejecting rants; yet Behe, Denton, and Meyer all endorse evolution.
I think he ran for the hills...
Possibly, but the original that I received from P.K. was not "lite up" as a directional link - it was black and did not have the "click-on" function (not sure how else to describe). Since you've sent the link such that I can click and get sent to that site, then I can access what was originally provided - thanks.
I'm a she and I don't believe I ever said I was an ID person. I said I believe ID should be taught in schools as it is in my daughter's private school. Atleast ID'ers scientifically poke holes in the Darwin school and consider that intelligence appears to be behind creation. I'm a total young earth creationist and proud of it.
Now, if you want to discuss my post about the topic..check post # 361
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