The Creationist Variation Barrier

I would like to know whether any creationist has ever supplied a mechanism that explains how variation within organisms is limited to "micro-evolution" but somehow cannot produce "macro-evolution". I've heard some arguments along the lines of "natural selection restricts the variation to within a certain limit, killing off those that are *too* different", but surely this would only apply in an unchanging environment where the selection pressures remain the same.Contributions from either side of the debate are welcome. Thanks.------------------
"Ah, there's nothing more exciting than science. You get all the fun of... sitting still, being quiet, writing down numbers, paying attention... Science has it all."-- Seymour Skinner, The Simpsons[This message has been edited by Eximius, 09-01-2003]

Eximus,Another I've heard is that protein families are immutable, since folding cannot occur via NS, allegedly.Mark

I would also like to know the biological basis of this supposed limit..for example has corn reached a limit?Proc Natl Acad Sci U S A. 2002 Jul 9;99(14):9573-8. Epub 2002 Jun 11. Related Articles, LinksIntraspecific violation of genetic colinearity and its implications in maize.Fu H, Dooner HK.The Waksman Institute, Rutgers University, Piscataway, NJ 08855, USA.Although allelic sequences can vary extensively, it is generally assumed that each gene in one individual will have an allelic counterpart in another individual of the same species. We report here that this assumption does not hold true in maize. We have sequenced over 100 kb from the bz genomic region of two different maize lines and have found dramatic differences between them. First, the retrotransposon clusters, which comprise most of the repetitive DNA in maize, differ markedly in make-up and location relative to the genes in the bz region. Second, and more importantly, the genes themselves differ between the two lines, demonstrating that genetic microcolinearity can be violated within the same species. Our finding has bearing on the underlying genetic basis of hybrid vigor in maize, and possibly other organisms, and on the measurement of genetic distances.Even within species there can be tremendous variation...this is within a species so it is "microevolution" (whatever that is supposed to imply...where are the limits to variation at higher taxanomic levels?Even in an unchanging environment with steady selection pressures one could expect a lot of variations on parts of the genome that are neutral...they would be free to drift apart randomly.cheers,
M

You all think that the question (Is Meso evolution BETWEEN micro and macro evolution?)by each of the three posters here (no mechanism to prevent transition thru meso, folding limiting the mating selection of protein family morphospace, positionally affected heterozygotes) indictes a BOUNDARY to biological change- prima facie denial of Bauplane/vertical changing formations of biological tissue.I think this is simply the wrong way to think thru the data of form of the offspring. I do not say how many partent generations are involved at all but it is not that I have a psychologically deviant synapse etc only that I READ this literature yet again in another way. We all know that there is SOME horizontal gene flow but I am not saying empirically that this amount is sufficient to hold up my writing as the reading itself is simply that you all are FINDING the boundary as a limit in your particularly interesting subjectivity and hence by locating it first within your one ideas you project this to the taxa involved in each individual thought and this indeed may make the supposed boundary that is indubitably common to all three to have limitations in the various cases. In modern biological terminology it is like finding an invarinace in the constraints but I also do not think this is the proper langague to SEE the complex as simple.What I meant was simply that even if the creationists supported a kinematics against long time changes (no-I do knot think or know of any MECHANICS that actually prohibits macroevolution trendy thinking(for one we need a better language that seperates mechanics and geometry (from artithemetic))
it may not limit in any way the quantity of change in taxogeny but it could alter how we think about speciation ( dont really try to second guess me here unless you are interested in getting into my own idosyncratic notion of Gould's contribution)
thus taxogeny simply is being misrepresented if not presented in these posts simply because I suspect there is INFINTE potential infinity in each lineage (to change-differences)
but one has to learn to see what kind of fractal"" changes may be indigenous, endemic, and particular to a particular part of biology (levels of selection vs levels of organization)
for there may indeed be manifold changes still going on only we need to learn to read not only the simple descriptions of biology differently but (also) the classical terms and retain some that have been provisionally put to the side (wild type, Leibig's law of the minimum,genic balance).I for one am not comfortable with all the traditional terminology of classical genetics because not coming to biology first from a moleuclar perspective I spent my time learning the shapes of whole organisms. This does not mean that I or you THINK about biology in any wrong way. Thinking biology is the first but reading it is not the last.[This message has been edited by Brad McFall, 09-01-2003]

Many people, including me, have problems with definitions like micro and macroevolution. There aren't any concise boundries between the two terms. It is almost like saying "near" and "far." If a person is walking away from you, at what point are they near you and at what point are they far away? Same thing with a building. At what point is a building short, tall, and skyscraper? Micro and macro seem too vague to serve any purpose.

Ex, had in the thread head logically rasied an issue that is crucial for me, namely whether a PRIOR Death is required in the molecular biology of "programmed" cell death or not. For if death before the program is required biologically then it is not at all clear that by merely using the Darwinin Individual will provide the science that nature may have already supplied to Mendel but this does not make the concept of "macro" evolution indicrimiante for it is precisely because the relations ARE percieved at this term that discussion indeed ensued but as far as I read is stopped up on evos developement of Woodgerian fucntor logic with or without Bauplanes. Certainly Huxley's notions of trends are not too hard to not understand. Part of this confusion undoubtedly arose historically in the biometric-mendelian difference of INTEERPREtation as indeed when Olby said it is AS IF"" development 'develops" the binomial it is only "as if" for I can perceive in Mendel the same in Pascal (DID MENDEL READ PASCAL?) as to any mathematical induction that keeps SOME math bionomial SEPRERATE from the combinations. Mendel had biology uppermost. Pascal had a binomial Galton could have kept clean too just as Mendel had the combinations broader than then signs he allowed himself the freedom to "type" (format) in but Ex asked what was the CREATIONIST MECHANSIM. Note a difference, I have not seen one. This unlike the evo-devo cardinality does not mean that it does not exist. I think it does. Evolutionists concentrating on trends and stuck with Morgan genetics could not do better than advance in West beyond anti-Morgan-mendelists abroad. It is time for creation biology even if it is not taught under this name. Let us simply understand that biological change whether with a mechanism explict or implicit need NOT be talked only under evolution. and who ever is changing my spellin transit please stop confusing people who may not catch all of the changes if I do not take the time research my own posts.-- I am sorry friends but someone is actually changing my transmssions in transit and I am quite mad about it.[This message has been edited by Brad McFall, 09-02-2003]