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.]
Well, there may be some evidence, but the trick is in the interpretation, and those demented Darwinists are always interpreting it to support their diabolical theory. But two can play that game. So if you take their "evidence" and lay out all their "fossils" in chronological order, and then look at the creatures in that sequence, what you see is ...
Well ... I mean ... it's all in how you interpret it. You know what I mean.
Ahhh, you were doing okay until that little backhanded slap. Then you went and blew it by throwing in another attempt at argument by insult. I have no problem with being "corrected" for my mischaracterizing something; just with the way in which it has been done.
Taking someones words out of context of other statements made, and ignoring those other statements in your attempt to "prove" whatever it is you believe you "need" to prove, is the argument of the weak. If there is "empirical evidence" to support the contention of ToE that one animal species "evolved" into a completely different animal species, then please, by all means, provide the "empirical evidence". Show me this has happened between two different species. Don't give me biologic, or anthropologic, or paleologic, or DNA guesswork. Demonstrate with actual empirical data (that which is demontrated to occur). Just pointing to pictured which pictorially present the "guesswork" of a theory is not empirical evidence that what ToE says happended, happended. It is just a guess based on fossilized remains. Maybe what you and ToE scientists are claiming is true. But don't just make the claim - back it up by demonstration of that happening.
People also commonly forget biogeography, a third great line of confirming evidence for evolutionary descent (though less sensational, perhaps...)
Don't be absurd. I supplied the a link to the full context of your words, which were absolutely clear. That you want to back away from what you said (as it was ignorant folly) is hardly surprising.
If there is "empirical evidence" to support the contention of ToE that one animal species "evolved" into a completely different animal species, then please, by all means, provide the "empirical evidence". Show me this has happened between two different species. Don't give me biologic, or anthropologic, or paleologic, or DNA guesswork.
I haven't supplied you with any guesswork. That you choose to see vast quantities of carefully studied data, predictions, and conclusions as "guesswork" says more about you, and your determination to not examine the issue properly, than the data and conclusions drawn. You have been supplied links to so much empirical data that you could spend months reading it. Presumably you'll believe electrons when someone has shown you one, you'll believe that stars are suns like ours when someone has taken you to visit one, and you'll believe in quantum events when you've seen one directly. Science deals in inference. Almost nothing is ever directly observed. To demand direct observation of processes that take millenia is simply (and wilfully) to set an impossibly high standard for proof, so you can avoid confronting the real evidence that does exist that convinces well over 99% of practicing biologists that evolution is a fact described by the theory.
It isn't just a guess, and the reasons why it is far more concrete than a guess have been explained to you ad nauseam. But you continue to misrepresent it as such. Intellectual dishonesty of this kind is so common amongst creationists that it no longer surprises me.
See 299.
There are only two viable political parties. You must vote straight ticket for the only party in which you have a voice.
Want to affiliate yourself with the political party in which NAMBLA, terrorist sympathizers, chickified males and other dim-wits and low-lifes have a voice, be my guest.
Oh please! Does anyone know what this really means. Please don't say I'm just too dumb to get. It takes understanding of a subject to be able to explain it.
No I have other options. I can decide NOT to vote or I can vote Libertarian.
You have no other options, sorry. You sit home, or you vote third party, you are casting your vote for a DemocRAT.
How so? He said he didn't believe in evolution or "punctuated equilibrium," and I agreed with him. In what possible way was that an "inaccurate portrayal"?
How should I be blunt about this... if the Republican party's platform includes putting ID into schools as science... then they damned well do not get my vote.
Voting for a third party is NOT the same as voting for Democrats. That is like Coke saying that drinking any other brand of soda is the same as drinking Pepsi.
You seem to be confused about the term "empirical". Sorry I confused you.
I do not believe in either evolution or punctuated equilibrium. However, I do accept the evidence that creates these models of how nature works. Such is science. Science is not a "belief". It is a series of rigorously tested models (theories) that describe the universe.
Then again, perhaps you weren't propagating an "inaccurate portrayal" of his position at all, and you were in fact agreeing with his position as precisely stated and qualified. Were you?
American Heritage says "empirical" means "Relying on or derived from observation or experiment".
Do you have a different definition? Because the one in the dictionary accurately describes the type of data the poster was referring to.
And, where exactly in any post I've made have I claimed that I believe the planet is only 6000 years old? My original question was much more scientific than that, as you well know. I asked (one more time into the breach) WHERE ARE THOSE FOSSIL TRANSITIONALS WHICH SHOW DIFINITIVELY THE MICRO- OR MACRO-CHANGES OF ONE SPECIES BECOMING A DIFFERENT SPECIES? I've yet to see those fossils anywhere in the fossil record. What has been presented are fossils which are similar in structure, but obviously from different animal species. As for the rest, well, as a fisherman I really enjoy putting bait out there for the little fishies to bite on. And, boy have they bit hard;)
Perhaps you should read this, which is a pretty good start on the issue of transitional fossils:
http://www.talkorigins.org/faqs/faq-transitional.html
The RAT party is the natural home of those who exhibit the "reasoning" abiliities of the dupes who were suckered into voting for Ross Perot. I think you would feel more at home with the one-armed boat-rowers on DU where everyone goes in circles like you do.
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