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Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
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Author | Topic: Punctuated Equilibria | |||||||||||||||||||||
Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
I just did a search of this site's forums, and didn't find any mention of the punctuated equilibria (PE) topic.
As stated at http://www.talkorigins.org/faqs/punc-eq.html , this is often a badly misunderstood concept. Indeed, before reading the above cited, I was under the impression that PE was when a radical mutation managed to survive as a new species. This idea has been referred to as the "fortunate monster" concept. Rather than that, PE actually states that a species population evolves over time in the standard way of mutations and natural selection. It, however, does this in a restricted geographical area (This restricted geographic area makes difficult the finding of the fossil remains that document the evolution). After some period of evolution, the now new species spreads to a broader geographic area. As such, it suddenly appears in the stratigraphy of those other areas, seemingly without any evidence of decent from the earlier species. See the above citation for more info. Regards, Moose ------------------Old Earth evolution - Yes Godly creation - Maybe
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Percy Member Posts: 22506 From: New Hampshire Joined: Member Rating: 5.4 |
I've more often heard Goldschmidt's idea described as the "hopeful monster" scenario. The big problem with this view is that the monster, hopeful or fortunate or otherwise, has no mate. Not only does this approach require a highly unlikely macro-mutation rendering the organism better suited to his environment, but it requires it to happen to at least two individuals, and they must be of the opposite sex.
Gould once wrote an article defending Goldschmidt by explaining that he was advancing the idea when evolutionary theory was at a lesser level of understanding, and that he wasn't actually advancing the precise idea that modern ears think he was. But I read the article some time ago and no longer remember the details. --Percy
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
quote: It would be nice to see the fossil record that Gould was studying to come up with the evidence supporting PE. Feeling to lazy to do a web search myself Regards, Moose Added by edit: I should also give Niles Eldredge credit for his part in the PE study. Guess Gould has the BIG name, and the good PR> ------------------Old Earth evolution - Yes Godly creation - Maybe [This message has been edited by minnemooseus, 01-12-2002]
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
Seems to me, that PE is due for a bump to the top.
Moose Added by edit: Just refound this link in another topic.
http://www.cs.colorado.edu/~lindsay/creation/punk_eek.html Havn't explored it deeply, but it seems to show much promice. Still Moose ------------------BS degree, geology, '83 Professor, geology, Whatsamatta U Old Earth evolution - Yes Godly creation - Maybe [This message has been edited by minnemooseus, 03-06-2002]
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
More info on PE:
Did a Scirus web search, and got these results:
http://scirus.com/... One of the links cited at the above is: All you need to know about Punctuated Equilibrium (almost)Common misconceptions concerning the hypothesis of Punctuated Equilibrium Copyright 2001 by Douglas Theobald [Last Update: January 24, 2002] At:
http://ucsu.colorado.edu/~theobal/PE.html Still Moose ------------------BS degree, geology, '83 Professor, geology, Whatsamatta U Old Earth evolution - Yes Godly creation - Maybe {Shortened display form of first link, to restore page width to normal - AM} [This message has been edited by Adminnemooseus, 02-09-2004]
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
The following is message 106 of the Great Debate topic "QUESTIONS". It was there posted by joz.
quote: MMM (Message Moving Moose) ------------------BS degree, geology, '83 Professor, geology, Whatsamatta U Old Earth evolution - Yes Godly creation - Maybe
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joz Inactive Member |
Hey Moose found this on Freds site is this you?
http://www.evolutionfairytale.com/images/moose1.jpg
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Dr_Tazimus_maximus Member (Idle past 3247 days) Posts: 402 From: Gaithersburg, MD, USA Joined: |
quote: Another aspect of this limited geographical area and limited population size is that this helps to perturb the Hardy-Weinburg genetic constraints concerning stability of allelic frequencies. This would allow for a more rapid accumulation of modified/mutated alleles without the "wash-out" effect, ie more genetic drift towards lower frequency alleles w.r.t. the mean frequency in the original parent population. I have Gould and Eldredges original PE paper here somewhere, I need to dig it up now. ------------------"Chance favors the prepared mind." L. Pasteur Taz UBB quote code fixed by Adminnemooseus [This message has been edited by Adminnemooseus, 10-12-2002]
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
This topic if relevent to another active topic, so I'm giving it a bump.
Two essential aspects of punk eek: 1) Happens in a geographicly restricted area. Thus, a widespread fossil record of the changes would not be expected to be found. 2) As pointed out by Taz, this results in a restricted species population size, which results in a faster evolution rate (to probably oversimplify the concept). I think this topic deserves far more discussion that what it has gotten. Moose ------------------BS degree, geology, '83; Professor, geology, Whatsamatta U; Old Earth evolution - Yes; Godly creation - Maybe My big page of Creation/Evolution Links
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Quetzal Member (Idle past 5902 days) Posts: 3228 Joined: |
Although I won't claim it's a peer-reviewed article ('cause I don't think Actionbioscience is peer-reviewed), I thought the group might like to read this article by none other than Niles Eldredge himself: Species, Speciation and the Environment. The article contains an excellent, non-technical discussion of PE from one of the originators of the idea. Enjoy.
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Mammuthus Member (Idle past 6506 days) Posts: 3085 From: Munich, Germany Joined: |
quote: ++++++++++++++++++++++++++++ Lenski has been doing work on this topic for about 10 years now using bacteria and lots and lots of generations of observations. Of course the punctuation would be much longer for multicellular organisms that have a longer generation time...but in relative terms it would be punctuated. CheersM Proc Natl Acad Sci U S A 1999 Mar 30;96(7):3807-12 Related Articles, Links Genomic evolution during a 10,000-generation experiment with bacteria. Papadopoulos D, Schneider D, Meier-Eiss J, Arber W, Lenski RE, Blot M. Abteilung Mikrobiologie, Biozentrum, CH-4056 Basel, Switzerland. Molecular methods are used widely to measure genetic diversity within populations and determine relationships among species. However, it is difficult to observe genomic evolution in action because these dynamics are too slow in most organisms. To overcome this limitation, we sampled genomes from populations of Escherichia coli evolving in the laboratory for 10,000 generations. We analyzed the genomes for restriction fragment length polymorphisms (RFLP) using seven insertion sequences (IS) as probes; most polymorphisms detected by this approach reflect rearrangements (including transpositions) rather than point mutations. The evolving genomes became increasingly different from their ancestor over time. Moreover, tremendous diversity accumulated within each population, such that almost every individual had a different genetic fingerprint after 10,000 generations. As has been often suggested, but not previously shown by experiment, the rates of phenotypic and genomic change were discordant, both across replicate populations and over time within a population. Certain pivotal mutations were shared by all descendants in a population, and these are candidates for beneficial mutations, which are rare and difficult to find. More generally, these data show that the genome is highly dynamic even over a time scale that is, from an evolutionary perspective, very brief. : Science 1996 Jun 21;272(5269):1802-4 Related Articles, Links Comment in:Science. 1996 Dec 6;274(5293):1748-50. Science. 1996 Jun 21;272(5269):1741. Punctuated evolution caused by selection of rare beneficial mutations. Elena SF, Cooper VS, Lenski RE. Center for Microbial Ecology, Michigan State University, East Lansing, 48824, USA. selena@ant.css.msu.edu For more than two decades there has been intense debate over the hypothesis that most morphological evolution occurs during relatively brief episodes of rapid change that punctuate much longer periods of stasis. A clear and unambiguous case of punctuated evolution is presented for cell size in a population of Escherichia coli evolving for 3000 generations in a constant environment. The punctuation is caused by natural selection as rare, beneficial mutations sweep successively through the population. This experiment shows that the most elementary processes in population genetics can give rise to punctuated evolution dynamics.
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
This link has recently shown up at the "NEWSFLASH: School..." topic ( http://EvC Forum: NEWSFLASH: Schools In Georgia (US) Are Allowed To Teach About Creation -->EvC Forum: NEWSFLASH: Schools In Georgia (US) Are Allowed To Teach About Creation ) :
It is the Kurt Wise article "PUNC EQ CREATION STYLE".Geoscience Research Institute | I think we need more research on that... I couldn't follow much of what he was trying to say, be it bad writing on his part, or, more likely, poor comprehension on my part. But, nothing jumped out at me, as being profoundly absurd. I just thought it would be a good thing, to get this creationist perspective view into the "Punctuated Equilibria" topic, before I lost track of it. Perhaps Kurt Wise deserves a topic of his own, somewhere here. Mr. Wise sure seems to have kept a low profile, considering his stature as a YEC paleontologist. Moose ps: In case it hasn't made this here topic before, Punctuated Equilibria was also mentioned in that message 118.
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
There seems to be some "punk eek" content showing up in a new topic, so I thought I'd supply a link to it.
It's the "Dawkins" topic, atEvC Forum: Dawkins Moose ------------------Professor, geology, Whatsamatta U Evolution - Changes in the environment, caused by the interactions of the components of the environment. My big page of Creation/Evolution Links |
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
MrHambre posted the following at http://EvC Forum: Always talking about micro-evolution? -->EvC Forum: Always talking about micro-evolution?
I thought it to be most worthy of being in the "Punk Eek" topic. ----- Skeptick asks:quote:I don't see what's so ludicrous about it. Gould and Lewontin combined the patterns of change paleontologists recognize in the fossil record with the results of population studies from people like R. A. Fisher. He demonstrated that the gaps in the fossil record are just where we would expect them. To use an analogy, think of the flip-movies you can draw on note pads. You draw a character on one side of the pad walking over to the other side by making each page a slight progression from the previous one. That was how we used to see the fossil record: species were each a slight progression from the last, in a smooth gradation from one to the other. The only reason the flip-movie of species wasn't gradual, people assumed, was that most of the pages were missing. Gould showed us a different flip-movie, where the character stays on the left side of the page for a long time, then suddenly he disappears when a new character appears in the middle of the page. Then he stays there for a long time, before suddenly he disappears when a third character appears on the right side of the page. The transitionals are still there, but the pages chronicling them are so few (and elapse so quickly) that we don't even notice them. The small populations where the real changes take place are not well represented in the fossil record because they weren't very numerous and weren't around for long. Fossils come instead from the large, stable species that don't show much change over time. And even recently extinct species like the passenger pigeon (which once numbered in the billions) don't seem to have left any fossils, so we can't assume there's paleontological record of every significant species.
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
Punctuated Equilibria keeps coming up in other topics.
It is an important and contentious issue, yet I seem to never be able to get this topic to go anywhere. I point out Punctuated Equilibria at EvoWiki. Now, I'm not a biologist and thus am not heavily into this stuff, but the illustration at the above cite strikes me as being somewhere between (for lack of a better term) deceptive and flat out wrong. It shows punctuated equilibria (PE / Punk Eek) as being "dotted line" gradualism. Comments from biologists? Moose
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