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"PROBLEMS OF EVOLUTION": 9. MECHANISMS (1) 1. Evolutionists cannot agree on 2. Time 3. Mutations 1. Random 2. Neutral 1. Haldane's Dilemma 3. Genetic drift 4. Competition 5. Natural selection 6. Adaptation 7. Speciation 8. Macroevolution 9. Stasis 10. Convergence 11. Contingency (chance)
"PROBLEMS OF EVOLUTION": 9. MECHANISMS (1) 1. Evolutionists cannot agree on This is not the only, nor the best, example of quotes I have on evolutionists appealing the fact of evolution (by which they mean common ancestry-which is not necessarily evolution) to paper over the cracks of their inability, after 140+ years, to agree on the mechanisms of evolution. Actually, it is the evolutionsts like Shermer who "will not get it". Without a mechanism of evolution, they really do not have a scientific theory of evolution, and indeed, they do not know that it was evolution! Note by the way that Shermer's admission that with a mechanism of evolution, "the theory of evolution will be stronger than ever", which must mean that without a mechanism of evolution, "the theory of evolution" is weaker than ever!:"Of the five points of Darwin's theory, the most controversial today are gradualism, with Niles Eldredge (1971, 1985; Eldredge and Gould 1972) and Stephen Jay Gould (1985, 1989, 1991) and their supporters pushing for a theory called punctuated equilibrium, which involves rapid change and stasis, to replace gradualism; and the exclusivity of natural selection, with Eldredge, Gould, and others arguing for change at the level of genes, groups, and populations in addition to individual natural selection (Somit and Peterson 1992). Ranged against Eldredge, Gould, and their supporters are Daniel Dennett (1995), Richard Dawkins (1995), and those who opt for a strict Darwinian model of gradualism and natural selection. The debate rages, while creationists sit on the sidelines hoping for a double knockout. They will not get it. These scientists are not arguing about whether evolution happened; they are debating the rate and mechanism of evolutionary change. When it all shakes down, the theory of evolution will be stronger than ever. ." (Shermer M.B., "Why People Believe Weird Things: Pseudoscience, Superstition, and Other Confusions of Our Time," W.H. Freeman & Co: New York NY, 1997, p.141. Emphasis in original) [top]2. Time Evolutionists commonly write as though time itself was a mechanism. For example, the late George Wald, Harvard Professor of Biology and Nobel laureate wrote of the origin of life that "Time is in fact the hero of the plot. ... Given so much time, the `impossible' becomes possible, the possible probable, and the probable virtually certain. One has only to wait: time itself performs the miracles" (Wald, 1954, pp.47-48). Similarly Dawkins wrote that: "... provided we postulate a sufficiently large series of sufficiently finely graded intermediates, we shall be able to derive anything from anything else, without invoking astronomical improbabilities. We are allowed to do this only if there has been sufficient time to fit all the intermediates in" (Dawkins, 1986, pp.317-318). However, this is fallacious if time is claimed, or implied, to be itself a mechanism. As Darwin himself pointed out: "The mere lapse of time by itself does nothing, either for or against natural selection. I state this because it has been erroneously asserted that the element of time has been assumed by me to play an all- important part in modifying species, as if all the forms of life were necessarily undergoing change through some innate law. Lapse of time is only, so far important, and its importance in this respect is great, that it gives a better chance of beneficial variations arising, and of their being selected accumulated, and fixed" (Darwin, 1872, p.101). [to be continued] [top] 3. Mutations 1. Random It is just assumed by evolutionists that all mutations in the 4 billion-year history of life have been random in the sense of undirected, because "no mechanism is known (to put the point mildly) that could guide mutation in directions that are non-random ... It is selection, and only selection, that directs evolution in directions that are nonrandom" (Dawkins, 1986, p.312). But quite clearly God could guide mutation in directions that are non-random, and in fact the leading Harvard botanist Asa Gray in Darwin's day proposed this as a scientific hypothesis (Dupree, 1959, p.296), which was however rejected by Darwin on theological grounds, but supported by the great geologist Charles Lyell (Darwin, 1875, pp.371-372; Wilcox, 1990, p.2:20). Quite clearly Darwinists cannot possibly know this, but just assume it on materialist- naturalist philosophical grounds, because even "the mutations studied in genetics laboratories" are too "macro" and therefore "less likely it is to be incorporated in the evolution of a species" (Dawkins, 1986, p.233), let alone mutations producing 'evolutionary novelties" which have "decreased in scope and in extent" with Homo sapiens, the last in line ... 100,000 years" ago (Grasse, 1977, pp.70-71). The actual experimental evidence that all mutation have been random in the sense of undirected is based on a mere handful of experiments over 50 years ago by Lederberg and Lederberg (1952), Luria and Delbruck (1943), and Demerec and Fano (1945), with bacteria and Darwinists take that as having "settled this question definitely" (Dobzhansky, et al. 1977, p.65)! In fact these crucial experiments which were employed by the Darwinists were based on a "falsehood", and the biological community, instead of pausing to ascertain whether all adaptive mutations in nature occur purely by chance", "jumped to the conclusion that they do and stuck to it," with "The consequence of that hasty act ... that a very damaging dogma came into being", namely "The dogma that all favourable variations which natural selection preserves arise purely by chance" (Opadia-Kadima, 1987, p.127; Corey, 1994, pp.252-253). But in any event, even if these experiments were valid, the fact that some mutations today in bacteria appear to be undirected does not necessarily mean that every mutation in all organisms throughout the entire 4 billion year history of life have been undirected (Denton, 1998, pp.285-286). In the final analysis, Darwinism (i.e. the modern Neo-Darwinian theory of evolution) is just a belief that "chance alone produced the favourable variations which natural selection preserved", and this has "equalled or surpassed the Christian belief in the creative power of God" (Opadia-Kadima, 1987, p.129; Corey, 1994, p.251)! [top] 2. Neutral"The neutral theory asserts that the great majority of evolutionary changes at the molecular level, as revealed by comparative studies of protein and DNA sequences, are caused not by Darwinian selection but by random drift of selectively neutral or nearly neutral mutants. The theory does not deny the role of natural selection in determining the course of adaptive evolution, but it assumes that only a minute fraction of DNA changes in evolution are adaptive in nature, while the great majority of phenotypically silent molecular substitutions exert no significant influence on survival and reproduction and drift randomly through the species." (Kimura M., "The Neutral Theory of Molecular Evolution," [1983], Cambridge University Press: Cambridge UK, 1990, reprint, p.xi)"This is the province of population genetics, a discipline given a remarkably sophisticated formulation in the 1930's and 40's by Ronald Fisher, J.B.S. Haldane, and Sewall Wright. Excellent mathematicians, these men were interested in treating evolution as a process expressed by some underlying system of equations. In the 1970's and 80's, the Japanese population geneticist Motoo Kimura revived and then extended their theories. Kimura's treatise, The Neutral Theory of Molecular Evolution (1983), opens with words that should prove sobering to any evolutionary psychologist: `The neutral theory asserts that the great majority of evolutionary changes at the molecular level, as revealed by comparative studies of protein and DNA sequences, are caused not by Darwinian selection but by random drift of selectively neutral or nearly neutral mutants.' If Darwin's theory is a matter of random variation and natural selection, it is natural selection that is demoted on Kimura's view. Random variation is paramount; chance is the driving force. This is carefully qualified: Kimura is writing about `the great majority of evolutionary changes,' not all. In addition, he is willing to accept the Darwinian disjunction: either complex adaptations are the result of natural selection or they are the result of nothing at all. But the effect of his work is clear: insofar as evolution is neutral, it is not adaptive, and insofar as it is not adaptive, natural selection plays no role in life." (Berlinski D., "On the Origins of the Mind,," Commentary, Vol. 118, No. 4, November 2004. Emphasis original)"Neutral sequences are by definition outside the surveillance of natural selection but this leads to a serious dilemma. As we have seen above, there is no conceivable way in which a uniform rate of drift could have occurred in organisms as diverse as mouse and man and yet the fibrinopeptides in rodents are isolated to exactly the same degree as those in primates. Drift seems be excluded. But selectionist explanations seem to lead to absurd conclusions. because the spacer sequences such as the fibrinopeptides exhibit the highest interspecies divergence of all proteins, if this is to be accounted for on purely selectionist grounds it is necessary to propose that they must have suffered adaptive changes very much more often than proteins such as the haemoglobins or the cytochromes. In other words, they must have been under the intense scrutiny of natural selection. Not only must such sequences have suffered more adaptive changes than other proteins but in addition, these substitutions must have occurred regularly. The difficulties associated with attempting to explain how a family of homologous proteins could have evolved at constant rates has created chaos in evolutionary thought. The evolutionary community has divided into two camps - those still adhering to the selectionist position, and those rejecting it in favour of the neutralist The devastating aspect of this controversy is that neither side can adequately account for the constancy of the rate of molecular evolution yet each side fatally weakens the other. The selectionists wound the neutralists position by pointing to the disparity in the rates of mutation per unit time, while the neutralists destroy the selectionist position by showing how ludicrous it is to believe that selection would have caused equal rates of divergence in " junk" proteins or along phylogenetic lines so dissimilar as those of man and carp. Both sides win valid points, but in the process the credibility of the molecular clock hypothesis is severely strained and with it the whole paradigm of evolution itself is endangered. There is simply no way of explaining how a uniform rate of evolution could have occurred in any family of homologous protein by either chance or selection; and, even if we could advance an explanation for one particular protein family, we would still be left with the mystifying problem of explaining why other protein families should have evolved at different rates." (Denton M., "Evolution: A Theory in Crisis", Burnett Books: London, 1985, p305)"I well remember how the synthetic theory beguiled me with its unifying power when I was a graduate student in the mid-1960's. Since then I have been watching it slowly unravel as a universal description of evolution. The molecular assault came first, followed quickly by renewed attention to unorthodox theories of speciation and by challenges at the level of macroevolution itself. I have been reluctant to admit it-since beguiling is often forever-but if Mayr's characterization of the synthetic theory is accurate, then that theory, as a general proposition, is effectively dead, despite its persistence as textbook orthodoxy." (Gould S.J., "Is a new and general theory of evolution emerging?," Paleobiology, Vol. 6, No. 1, January 1980, p.120)"Despite its biological importance, positive selection is seldom observed at work in nature. A few well- known, and constantly cited examples are industrial melanism in moths (Kettlewell, 1955, 1956, 1958), DDT resistance in insects and antibiotic resistance in bacteria. As compared with these, examples of negative selection are abundant; it is popular to associate unfavourable effects and deformities with mutations, as so many textbook examples of mutants are of this nature. Furthermore, intensive studies of recessive lethals and detrimental mutants in Drosophila populations have shown beyond doubt that the majority of these mutant genes are unconditionally deleterious both in homozygous and heterozygous states (Mukai and Yamaguchi, 1974; Mukai et al., 1972). (Kimura M., "The Neutral Theory of Molecular Evolution," [1983], Cambridge University Press: Cambridge UK, 1990, reprint, p.118)[top] 1. Haldane's Dilemma"Kimura's estimate is based essentially on an argument first put forward by Haldane 4 (Haldane J.B.S., J.Genet., Vol. 55, 1957, p511); it is this argument which I believe to be erroneous. Haldane bases his argument on the idea of the "cost" of natural selection. The unit step in evolution is the substitution of one allele, say A, for another, a, in a population. This happens because individuals carrying the gene a are killed selectively or because they have a lower fertility. The larger the number of selective deaths, the more rapidly will gene frequencies change. Haldane estimated the total number of selective deaths (that is, deaths of individuals who would have survived had they had the optimum genotype) required to substitute one allele for another. He concluded that, for a diploid population with moderate selective advantage, the total 'cost" of selection would be between 10 and 100 times the population size, per gene substitution. Now there is an upper limit to the number of selective deaths which can occur in one generation. Thus if, for example, a population consisting wholly of individuals of optimal genotype could in favourable circumstances increase by a factor R. then the fraction of selective deaths cannot be greater than (R-1)/R per generation. This places an upper limit on the rate of evolution." (Smith J.M., "`Haldane's Dilemma' and the Rate of Evolution," Nature, Vol. 219, 1968, p.1114)"HALDANE'S DILEMMA Consider a population in which a gene A1 confers on its carriers a Darwinian fitness greater than in the carriers of A2. Natural selection acts to enhance the frequency of A1 and to reduce that of A2. This may happen because the progeny of A1 survive more frequently than of A2, or because the former have a greater fecundity, sexual activity, longevity, or any combination of these and other advantages. Whatever the cause, one may say that carriers of A2 are eliminated by `genetic deaths.' Substitution of more favorable for less favorable alleles by natural selection occurs at a `cost,' and imposes upon the population a `substitutional' genetic load. The concept of substitutional load has a paradox at its core. Imagine a population in which every member has a high Darwinian fitness; a new and still more favorable mutation arises; now every member except the carrier of the mutant has a new genetic load that must be eliminated for the population to reach a still higher level of fitness. In 1957 Haldane analyzed the consequences of this situation. During the passage of a favorable mutant from its origin to fixation many individuals have to suffer genetic death; the number of such individuals is generally much greater than the number of individuals alive in any one generation. Crow and Kimura (1970) give the following example of gene substitution `if the typical allele has an initial frequency of l0-4, a population of one million individuals will have to have nine million genetic deaths each generation if it is to substitute an average of one allele per generation. Or more probably, if there is to be a gene substitution every 100 generations, the average fitness will be lowered by 0.09.' Now, in evolution many genes must be changed to transform one species into another. Granted that most living species produce numbers of progeny far in excess of those needed to have the population survive, it is difficult to understand how evolution can happen at such an enormous cost in genetic deaths. Haldane saw clearly that he was confronted by a dilemma. In his words, `I am quite aware that my conclusions will probably need a drastic revision. But I am convinced that quantitative arguments of the kind here put forward should play a part in all future discussions of evolution." (Dobzhansky T., Ayala F.J., Stebbins G.L. & Valentine J.W. "Evolution," W.H. Freeman & Co: San Francisco CA, 1977, pp.163-164)"A new selection pressure is added whenever directional selection favors the replacement of an existing allele by a new allele. How rapidly can such a replacement take place and how much of a "cost" does it involve? Haldane (1957) was the first to recognize this problem and to try to supply a quantitative answer to it. He assumed that gene substitution in a species occurred through the "death" in each generation of a constant fraction of individuals carrying the particular gene. On that basis he calculated that the total number of "selective deaths" required to complete one substitution is of the order of 30 times the population size, independent of the intensity of selection. Haldane concluded from this that the replacement of one gene by another had to be a slow process, requiring an average of 300 generations per substitution. Furthermore, he and Kimura (1960) estimated that the survival of the population would be jeopardized if gene substitution took place at more than about a dozen loci at any one time. The more general conclusion was that evolutionary change is an exceedingly slow process. If two species differ at 1000 loci, Haldane estimated that it may have taken at least 300,000 generations to complete speciation." (Mayr E., "Populations, Species and Evolution," [1963], Harvard University Press: Cambridge MA, 1974, reprint, p.158) [top]See http://groups.yahoo.com/group/CreationEvolutionDesign/message/11499 3. Genetic drift 4. Competition"Is There Evidence That Evolution Based on Reduction of Competition Has Been Widespread? Many authors have suggested that current competition is no more obvious than it is because prior competition has produced communities composed of species that now live harmoniously. An absence of current strong competition is not evidence against the importance of competition, but for it. Joseph Connell (1980 [Connell J.H. "Diversity and the coevolution of competitors, or the ghost of competition past," Oikos, Vol. 35, 1980, pp.131-138]) termed this result `the ghost of competition past,' a phrase that captures the spirit of the idea. A process of divergence would occur such as we have described and illustrated earlier .... If this process is a frequent one, we ought to be able to find cases in which two species, when they occur separately (allopatric), are similar but differ when they occur together (sympatric). ... termed character displacement ... One of the best examples of character displacement involves the small and medium ground finches (Geospiza fuliginosa and Geospiza fortis) of the Galapagos studied by David Lack (1947). ... How many other clear-cut examples of morphological character displacement are known? Their answer is, surprisingly few. " (Brewer R., "The Science of Ecology," [1988], Saunders College Publishing: Ft. Worth TX, Second Edition, 1994, p.290)."Two aspects of animal life impressed me most during the journeys which I made in my youth in Eastern Siberia and Northern Manchuria. One of them was the extreme severity of the struggle for existence which most species of animals have to carry on against an inclement Nature; the enormous destruction of life which periodically results from natural agencies; and the consequent paucity of life over the vast territory which fell under my observations. And the other was, that even in those few spots where animal life teemed in abundance, I failed to find -although I was eagerly looking for it-that bitter struggle for the means of existence, among animals belonging to the same species, which was considered by most Darwinists (though not always by Darwin himself) as the dominant characteristic of struggle for life, and the main factor of evolution. ... I conceived since then serious doubts-which subsequent study has only confirmed-as to the reality of that fearful competition for food and life within each species, which was an article of faith with most Darwinists, and, consequently, as to the dominant part which this sort of competition was supposed to play in the evolution of new species. On the other hand, wherever I saw animal life in abundance ... I saw Mutual Aid and Mutual Support carried on to an extent which made me suspect in it a feature of the greatest importance for the maintenance of life, the preservation of each species, and its further evolution." (Kropotkin P., "Mutual Aid: A Factor of Evolution," [1902], Freedom Press: London, 1987, pp.12-14)"Influenced by Malthus and by the social philosophy of his time, Darwin emphasized the negative aspect of biotic interaction. He painted a picture of species aiming at mutual destruction in their struggle for life. Misled by the Malthusian implication of the finite area on the surface of the Earth, Darwin (1859, p. 67) compared it to `a yielding surface, with ten thousand sharp wedges packed close together and driven inwards by incessant blows, sometimes one wedge being struck, and then another with greater force,' forcing out a previously struck wedge. `The boat is full,' as the Swiss said in justifying the closure of their borders to refugees during World War II. But the boat is not full. Darwin's younger contemporary, Peter Alexander Kropotkin, advocated the opposite view of mutual aid and symbiosis in evolution. Darwin's view of killing the competition reflected the philosophy of his time. The motto of our age is peaceful coexistence and symbiosis. Niklas (1986) pointed out that increase of species could be absorbed through a `partition of ecologic niches.' In the evolution of fossil communities, we see a picture of interdependence of plants, insects, and terrestrial animals. This evolutionary pattern indicates the constructive aspect in the history of life. The Earth was probably made inhabitable through the effort of anaerobic bacteria that gave us oxygen in the atmosphere. New groups evolved, but they did not always ride over the dead bodies of the old. They ventured out and created new ecologic niches for themselves and for others as well (Lovelock, 1980)." (Hsu K.J., "Darwin's three mistakes," Geology, 1986, Vol. 14, pp.533-534) [top]
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Created: 3 November, 2003. Updated: 12 March, 2006.