"You do not have links to that evidence!"
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.]
That didn't work either.
http://www.talkorigins.org/index/CC/CC200.html (what you wrote)
http://www.talkorigins.org/indexcc/CC/CC200.html (what Professor Kill wrote)
See the difference?
I really don't know why I'm bothering, but:
http://www.talkorigins.org/indexcc/CC/CC200.html
http://en.wikipedia.org/wiki/List_of_transitional_fossils
http://www.asa3.org/asa/resources/Miller.html
http://members.aol.com/darwinpage/transitionals.htm#Transitionals
http://members.aol.com/darwinpage/hominid.htm
Pearls to swine placemarker
Yes, but never forget, the lurkers can see who presents evidence, and who responds, "You can't make me see!"
Not just the lurkers. Everyone can see it. Except, maybe, the person who has his hands over his eyes so he can't see anything.
How punctuated do you have to believe it was before you become an evil Creationist.
Bookmarked
Lead a horse - Placemarker -
It has everything to do with it actually. You choose to go back to time X+1 and determine how Y evolved from this point. I am asking where X came from. I am going to the crux of the matter. Saying this has nothing to do with evolution is foolish.
I once calculated using the temperature of the cosmic background radiation, the temperature of quark confinement, the volume of a sphere, and rough estimates of cosmological and geological timescales to find that 6 days = 15.4 billion years, and the end of the 7th day is in a few hundred thousand years. (Yes this is based on Gerald Shroeder)
Not as cool as the 2012 Mayan end of the world date, and both sides have shredded Shroeder's argument for the alignment of Genesis timing (I find the critiques misunderstand either the science involved or the Bible). I would like to think though, that humanity will fully explore the universe before time is up.
Dunno.
The universe is a BIG place, a few hundred thousand years is such a short time.
"The universe is a BIG place, a few hundred thousand years is such a short time."
A couple thousand years ago, the Earth was a huge place. I suspect that eventually, getting TV from across the universe will only have a 5-second delay for bleeping out profanity.
"Robertson? I mention Robertson only once and use him to prove the point that ID is Creationism, not science. I did not discuss Robertson at all in my post afterward. Therefore, I did not rant about him at all did I?
Nice spin... you avoided all the points I brought up by deceptively claiming my post was a rant about Robertson. I really don't like it when people pull that crap on me. I feel it is dishonest."
According to your definition, your comments above demonstrate a rant.
Are you still here spinning? You lost OK? I caught your deception and you couldn't address any of my points. Now quit digging that hole you are in any deeper... it is embarrassing to watch.
Red X!
How did you do that?
"I am asking where X came from."
See post #350.
I answered your questions. Obviously not the answers you wanted but that's rather mute isn't it? Your obvously an egotistical control freak.
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