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.]
Methinks ol' Pete should just stick to singing. "I'm 'enry the Eighth, I am..."
Thanks for the info and link.
So, because of my questions regarding certain "assumptions" made be TOE, I'm ignorant about the TOE, right?
If you have time, please see the article on the "Santorum Amendment" to the No Child Left Behind act.
http://en.wikipedia.org/wiki/Santorum_Amendment
As is the amount of genetic evdence, if you believe the article
No, actually I was not calling you ignorant at all and I am not sure where that came from. I just wanted to know should I bother citing any evidence whatsoever. I really don't want to get into a debate because it always turns out the same; an exhausting effort to explain to someone something they will always refuse to believe no matter what.
You asked "is Evolution real". The answer is Micro Evolution is most certainly real. The evidence for Macro evolution is "harder" for people to agree on because of the number of generations it takes for it to happen but the fossil record heavily suggests it.
I would recommend you look here: http://www.freerepublic.com/~patrickhenry/
Why don't you provide evidence that the things you want proof of are not happening?
Order your Unknowledge Troll Kit today; and we'll throw in a companion manual "Anti-Science for Luddites" as a free bonus. And remember, no edjucashun or intellectual ability is required to be an "Unknowledge Troll -- an obnoxious sense of entitlement to disrupt discussions of people far smarter and better edjukated that you are is all you need! ORDER TODAY, AND BE ALL YOU CAN BE!"
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That is very good, except for the below.
Btw, it should read: "...required to be an "Unknowledged Troll."
LOL!
That is funny.
Nay, that's not funny...it's humorous.
"That's the proper thing to do.
Yes, I understand about giving credit to the author. Just wanted permission from you to use it.
Thank you.
Sure. Use it all you like. Just tell 'em where it came from.
Well, if you don't post the evidence, how do you expect us non-believers to be converted to evolution.
Theories must be backed with evidence if they are to be believed, I believe.
Theories must be backed with evidence if they are to be believed, I believe.
The evidence is enough to convince hundreds of thousands of scientists around the world. The theory of evolution has withstood repeated tests for 150 years.
It isn't the "non-believers" who have trouble seeing the evidence. It is believers. Particularly believers in a literal interpretation of Genesis. They are blinded to the world of science by their religious belief, and will oppose anything that contradicts that belief--no matter how well documented.
That in of itself is not a problem. They are free to believe anything they want. The problem comes when they try to override science with religious belief.
Rather than say, "My religion teaches that this is the way things started" they are more apt to attempt to use science to show, for example, that evolution is based on unwarranted assumptions, radiometric dating is wrong, geology proves a global flood, and the earth is only 6000 years old. But to do this they have to distort the methods and results of science. The simplest of these distortions are "Its just a theory!" and "Teach the controversy!"
Not surprisingly, these distortions and, on occasion, outright fabrications, tend to annoy scientists who have spent decades studying and learning their fields.
No sh*t, sherlock.
The problem is, -- how to put this delicately?
Try it like this: there are a number of components to what we call "evolution" including sudden changes in environment, sudden fortuitous changes propagating in a more stable environment or to spread into an environmental niche, and drift.
Without knowing "enough" details about both a species and its environmental niche, how much confidence can one have in the molecular clock--not "see, it's all nonsense" but "what *are* the error bars on that estimate?"
Eagerly reading the rest of the piece...
Cheers!
The same way that the children of Sam Walton are all billionaires despite the meager profit margin at Wal-Mart.
There have been so *many* animals and plants, that even though the chance of any particular one being fossilized is small, the total number of fossils is stil considerable...
Cheers!
Not always. That's what got Pope Benedict in trouble during his recent comments on Islam.
Scholasticism and reliance on ancient texts and the teachings of those around before you is not *empiricism*; but it does share some similarities in that one cannot make things up on one's own "out of whole cloth".
Hence Newton's famous quote that "If I have seen farther than others, it is by standing on the shoulders of giants."
...and the lament of many a grad student, "If I cannot see as far as others, it is because students are standing on my shoulders."
PS...sorry that the Twins lost to the A's.
Cheers!
Obviously you're an antievolutionist, but I still don't understand why you react to strongly to this specific research. Note the the analysis was only done on "closely related species," doubtless in nearly all cases those that even the strictest creationists consider members of the same "created kinds." IOW creatures that even creationists think are related by normal biological reproduction, i.e. evolution.
"It isn't the "non-believers" who have trouble seeing the evidence. It is believers."
Well, a believer is someone who already believes, or has faith, in evolution. The non-belivers are the ones who need to be converted to evolution.
Why convert the already converted? It don't make no sense.
I agree with some of the points you make, but evolution is not a hard science as, say, mathematics or physics is. Hence, the reason why many people don't believe in it until there is solid, unshakable evidence that proves what it purpots to claim.
Btw, I don't believe the earth to be 6,000 years old. I believe it to be much older but have doubts to the estimated 4.5 billion years. But that's understandable. Could be 3 billion years or 2.5.
Anyway, my objection to evolution's claims is that it is not a precise science, far from it. Also -- and this is the primary reason why I must presently discard it -- it goes against a God or a creator, or the mystery of life, if you will. Moreover I believe that supporters and believers in evolution are very zelous about it, which tells me that they must have an agenda. I reason that this agenda is one that goes against the survival of Western Culture and Christianity. Were they not so zealous and anti-Christians, I may allow allow myself to be coaxed into their camp and "see the light." Until then, any theory that attempts to destroy my culture and people, I will fight them, even if there is solidity to it and not mere wind.
And that's where I stand.
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