dubois@uwmacc.UUCP (Paul DuBois) (05/15/85)
>> In article <942@uwmacc.UUCP> dubois@uwmacc.UUCP (Paul DuBois) writes: >> Pierre Grasse', "Evolution of Living Organisms: Evidence for a New >> Theory of Transformation". Academic Press, New York, 1977. >> >> "Some contemporary biologists, as soon as they observe a mutation, >> talk about evolution. They are implicitly supporting the following >> syllogism: mutations are the only evolutionary variations, all living >> beings undergo mutations, therefore living things evolve. >> "This logical scheme is, however unacceptable: first, because its >> major premise is neither obvious nor general; second, because its >> conclusion does not agree with the facts. No matter how numerous they >> may be, mutations do not produce any kind of evolution. > [Mike Huybensz] > Grasse' is correct here, in the same sense that wood does not produce a > house. Mutations are thought to be the raw material of evolution: > recombination and selection compose the actual process. > However, his syllogism is a straw horse. Partly because of the distinctions > between microevolution and macroevolution. I don't understand what you mean. >> "We add that it would be all too easy to object that mutations have >> no evolutionary effect because they are eliminated by natural >> selection. [Note that this is exactly the role natural selection plays >> according to many creationists - pd] Lethal mutations (the worst kind) >> are effectively eliminated, but others persist as alleles. The human >> species provides a great many examples of this, e.g., the color of the >> eyes, the shape of the auricle, dermatoglyphics, the color and texture >> of the hair, the pigmentation of the skin. Mutants are present within >> every population, from bacteria to man. There can be no doubt about >> it. But for the evolutionist, the essential lies elsewhere: in the >> fact that mutations do not coincide with evolution." [p88] > Population genetics has explained for decades that mutations (excepting > dominant lethals) are NOT eliminated from populations: they are maintained > at a relatively constant low level. This is the idea of genetic load > (for harmful mutations.) Yes, that's what Grasse' said. I don't understand your point. >> (Note to Mike Huybensz: the above is the answer to your question "what >> did he say?" that you posted in response to the citation of Grasse' in >> one of the "Case for Creation" articles.) > And as can be seen from the above, it certainly doesn't refute evolution > nor support creationism. Nor does it give any positive support to evolution. But in my comment I was merely pointing out that this was the passage which provides you with the information you asked for. I wasn't trying to argue with you. >> Earlier he says regarding bacteria: "Bacteria, the study of which has >> formed a great part of the foundation of genetics and molecular >> theory, are the organisms which, because of their huge numbers, produce >> the most mutants ... The bacillus _Escherichia coli_, whose mutants >> have been studied very carefully, is the best example. The reader >> will agree that it is surprising, to say the least, to want to prove >> evolution and to discover its mechanisms and then to choose as a >> material for this study a being which practically stabilized a billion >> years ago! > Why will I agree? The choice of bacteria was made because (pragmatically) > they have relatively simple genetic systems with fewer variables, and > thus are easier to experiment upon. It would be foolish to experiment ONLY > on them: but this hasn't happened. And the mechanisms discovered have been > confirmed in eucaryotic organisms as well. > The information discovered also reveals that bacteria have not "stabilized": > they are in constant genetic flux, exchanging chromosomal material through > viruses and sex. And they are still bacteria, which was his point. >> "What is the use of their unceasing mutations if they do not change? >> In sum, the mutations of bacteria and viruses are merely hereditary >> fluctuations around a median position; a swing to the right, a swing >> to the left, but no final evolutionary effect." [p87] > How does he know they do not change? How would they refrain from mutating? He does not mean that "they do not change because they do not mutate." He means that they mutate ad nauseum and they remain bacteria. > The idea of fluctuations around a local optimum is an important one for > explaining stability of species, but overlooks the possibility of new > and changing environments providing new local optimums. And since it is possible, it must be true? The fallacy of the possible proof. -- | Paul DuBois {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois --+-- | In the human instantiation, the image is the substance. |
keithd@cadovax.UUCP (Keith Doyle) (05/17/85)
[..............] >> The information discovered also reveals that bacteria have not "stabilized": >> they are in constant genetic flux, exchanging chromosomal material through >> viruses and sex. > >And they are still bacteria, which was his point. [DuBois] > >>> "What is the use of their unceasing mutations if they do not change? >>> In sum, the mutations of bacteria and viruses are merely hereditary >>> fluctuations around a median position; a swing to the right, a swing >>> to the left, but no final evolutionary effect." (p87) > >> How does he know they do not change? How would they refrain from mutating? > >He does not mean that "they do not change because they do not mutate." >He means that they mutate ad nauseum and they remain bacteria. > >> The idea of fluctuations around a local optimum is an important one for >> explaining stability of species, but overlooks the possibility of new >> and changing environments providing new local optimums. > >And since it is possible, it must be true? The fallacy of the >possible proof. I might agree with you if it weren't for the other supporting evidence that speciation occurs, i.e., all mammals have related bone structures, other features etc., and their DNA is more closely related to each other than to reptiles, fishes, bacteria, etc. The mutations that we are all talking about, take place as changes in the DNA. Some changes may have profound effects on the organism, producing an animal that may be unable to survive. Other changes may be so slight as to not be noticed at all. Since DNA determines charateristics of an organism, including species, there is no reason to believe that enough mutations cannot occur over a period of time as to effectively transform one species into another. And, there is plenty of reason to believe that species transformation CAN occur. In fact, there is no evidence of dividing lines that you can use to determine exactly where an animal becomes a new species. The only potential criteria that has been proposed, is that different species cannot mate and produce fertile offspring, or perhaps cannot mate and produce offspring at all. Reproductive isolation is not a particulary good criteria for determining species. It may be, that the difference in DNA required to prohibit cross-species reproduction may actually be very slight, while the difference in DNA allowed while still maintaining inter-fertility could be significant. What then, is the actual criteria for differing species? Reproductive isolation may *encourage* similar species to diverge, but it is not necessarily a mandate. At the same time, using some percentage of DNA similarity is probably not a good mechanism for determining species. What this all boils down to, is that any percieved lines between species kind of dissolve, and perhaps the entire notion of species is pretty darn fuzzy. How do you tell when yellow becomes green in the electromagnetic spectrum? At 49% yellow and 51% green? That may only be because you have an exact definition of what yellow is and what green is. Keith Doyle # {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd