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.]
Oops!
I think you meant evolutionists' loss of direction.
Well, one example is their understanding that apes eventually evolved into humans, which is not my understanding of the ToE.
See above.
"What ape species do you believe that those who accept evolution believe eventually evolved into humans, and why do you believe tha the theory of evolution implies that no other ape species should exist today?
The one and only ape species that, again, according to evolutionists, evolved into humans. I'm not the one making the assertion that apes in general or a single species evolved into humans. Evolutionists do.
Wife is calling.
I gotta go now, but I can come back tomorrow during your allotted time and continue this discussion.
LOL. Love your reply and you screen name too!
LOL, now that you put it that way. I don't really have a dog in this fight, but I've always found that the arguments focus on the wrong thing. If evolution is true, how did the very first molecule appear in the universe? What/who created it? And if it was God, how/who created him. In the end, this very simple question leads me back to one conclusion. The other details aren't as important once you can answer this question.
From your screen name alone I can tell you belong here. Don't let the individual personalities here tell you if you belong. Do you believe in the basic tennants espoused ont he home page here? That's the question.
Weren't some of the astronomers who believed the planets revolved around the sun and not earth also castigated?
However... there is one line in the statement that I wished would be clearer. He said, "We oppose all forms of liberalism, socialism,...,government enforced atheism,...
Now I don't approve of government enforced atheism, but many people on this forum probably equate that line with teaching Evolution, right? If that is what he meant, then that would be about the only part I take issue with.
I don't know what he means, but it's not what I get from it.
I sure wish I knew the answer to that question. When you get right down to it several things that are pretty darn miraculous have happened to result in us being here. Both the scientific and religious theories regarding the origins of the universe and life sound pretty implausable from a rational perspective. In my own experience things don't just pop out of nowhere, inanimate objects don't come alive and supernatural dieties are nowhere to be found, but the fact remains that both the universe and life are here and something pretty fantastic must have happened to account for them.
Well neither do I... and maybe he doesn't either because so far the posters in favor of teaching Evolution have not Zotted.
To compare Scientology to ID is well, just as ridiculous, as saying man evolved from apes . ID has tons of brilliant scientists who support their evidence more scientifically than so called "evolutionary scientists." And yes, I do want ID, creationism taught as competing theories to the ridiculous assertion that somehow man evolved from pond water . I actually believe evolutionary theory has more in common with the Church of Scientology than ID does.
It's also true that most American people agree with me.
There is no scientific proof for evolution despite the illusion.
My kids attend private schools known for academic excellence and guess what? They present ID and your basic fish to man theories.
As for a detailed discussion of the science, try reading all the other threads on these topics or perhaps go buy some ID books or books that go into huge detail about the evolving lies of evolution .
Boxen,
Everything I said was true - when I said pond water, I suppose I could be more specific and site the famous Stanley Miller prebiotic soup experiment that the scientific community embraced. If you read about this model, I would suggest I was being kind in using that description.
Well, I believe if you actually study all the evolutionary theories , for example, the specific topic of this post, punctuated equilibria, you will understand my assertion.
I believe all polls taken support this - you could use your search engine to confirm this.
Again, just a few decades ago, scientists believed organic molecules collected in the oceans and formed a primordial soup, thick with nutrients "like a chicken broth." Pond water actually would have had more validity.
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