Creation/Evolution Quotes:
Origin of Life #5: Simulations Creation/Evolution Quotes:
Origin of Life #5: Simulations"In sum the ease of synthesis of 'the molecules of life' has been greatly exaggerated. It only applies to a few of the simplest and in no case is it at all easy to see how the molecules would have been sufficiently unencumbered by other irrelevant or interfering molecules to have allowed further organisation to higher-order structures of the kinds that would be needed: message tapes, selective control structures, etc. Finally, even if I am wrong about all this and primitive geochemistry had shown a precision in organic reaction control quite unlike modern geochemistry; even if it had produced all 'the molecules of life' and nothing but 'the molecules of life' in ample amounts; even then it would still only have reached the edges of the real problem as outlined in the first four chapters. Still, somehow, an evolving machine had to be made." (Cairns-Smith, A. Graham, [Reader in Chemistry, University of Glasgow], "Seven Clues to the Origin of Life: A Scientific Detective Story," Cambridge University Press: Cambridge UK, 1993, reprint, p.44)
[top of page]"At a recent meeting in Chicago, a highly distinguished international panel of experts was polled. All considered the experimental production of life in the laboratory imminent, and one maintained that this has already been done-his opinion was not based on a disagreement about the facts but on a definition as to just where, in a continuous sequence, life can be said to begin." (Simpson, George Gaylord [Professor of Vertebrate Paleontology, Museum of Comparative Zoology, Harvard University], "The World into Which Darwin Led Us," Science, Vol. 131, No. 3405, 1 April 1960, pp.966- 974, p.969).
[top of page]"Creationists have looked forward to the day when science may actually create a "living" thing from simple chemicals. They claim, and rightly so, that even if such a man-made life form could be created, this would not prove that natural life forms were developed by a similar chemical evolutionary process. The scientist understands this and plods on testing theories." (Stansfield, William D. [Professor of Biological Sciences, California Polytechnic State University], "The Science of Evolution," [1977], Macmillan: New York NY, 1983, Eighth Printing, pp10-11).
[top of page]"All this is dreadfully wrong, however. The methane used by Urey and Miller was almost surely obtained from natural gas, and so was of biological origin. The ammonia was also of suspect origin, just as it was in Wohler's experiment. So what was actually done was to start with biomaterials and from them produce other biomaterials, a far less impressive outcome than it seemed at the time. If Urey and Miller, and their successors, had used only materials that were genuinely inorganic in the terrestrial context and had obtained similar results, the achievement would have been more impressive. The correct materials to use would have been water, nitrogen, and carbon monoxide and dioxide, for the reason that these substances might have occurred quite naturally on the early Earth before the onset of biological processes." (Hoyle, Fred [late mathematician, physicist and Professor of Astronomy, Cambridge University], & Wickramasinghe, Chandra, [Professor of Applied Mathematics & Astronomy, University of Wales], "Our Place in the Cosmos: The Unfinished Revolution," Phoenix: London, 1993, pp.28-29).
[top of page]"It is true that some of the simpler amino acids have been found in complex mixtures generated under conditions simulating those that might have been present on the primitive Earth. Even nucleotide letters have been found in mixtures that are said to be plausible simulations of probiotic products. But all such 'molecules of life' are always minority products and usually no more than trace products. Their detection often owes more to the skill of the experimenter than to any powerful tendency for the 'molecules of life' to form." (Cairns-Smith, A. Graham, [Reader in Chemistry, University of Glasgow], "Seven Clues to the Origin of Life: A Scientific Detective Story," Cambridge University Press: Cambridge UK, 1993, reprint, pp.44-45).
[top of page]"Difficulties arise when we try to take the simulation process any farther, by leaving the amino acids, nucleic acids, fats and carbohydrates lying around in the conditions expected to have prevailed on primitive Earth. Genes, enzymes, molecules of transfer RNA and living cells do not, of course, arise with as much ease as their basic components. The ultimate proof of the modern theory of genesis-the emergence of life from the "test tube"cannot be made to work. At least not yet." (Scott, Andrew [biochemist and science writer], "Update on Genesis," New Scientist, Vol. 106, No. 1454, 2 May 1985, pp.30-33, p.30)
[top of page]"Assuming that terrestrial life did evolve on the earth, what was the planet like when the process began? One thing is certain: the atmosphere contained little or no free oxygen and hence was not strongly oxidizing as it is today. The organic matter that must accumulate as the raw materials from which life could evolve is not stable in an oxidizing atmosphere. One tends to forget that oxygen is a dangerously corrosive and poisonous gas, from which human beings and other organisms are protected by elaborate chemical and physical mechanisms. Many bacteria and all higher forms of life "burn" their food by combining it with oxygen, because this process yields far more energy per gram of fuel than simple anaerobic (nonoxygen) fermentation. Enzymes such as catalase, peroxidase and superoxide dismutase have evolved to protect oxygen-using organisms from toxic side effects. Anaerobic bacteria lack these protective systems; for them oxygen is both useless and lethal. J. B. S. Haldane, the British biochemist, seems to have been the first to appreciate that a reducing atmosphere, one with no free oxygen, was a requirement for the evolution of life from nonliving organic matter." (Dickerson, Richard E. [Professor of Molecular Biology, University of California, Los Angeles]., "Chemical Evolution and the Origin of Life," Scientific American, Vol. 239, No. 3, September 1978, p.62) .
[top of page]"The Chemical Evolution Theory requires that an oxygen-free atmosphere existed for a considerable period of time on the early Earth. Geological evidence from the early PreCambrian, however, suggests that such primitive and secondary atmospheres did not exist for any appreciable length of time. Supporting evidence for this comes from studies of the ultraviolet photolysis of methane to give polymeric materials. These studies suggest that under primitive-Earth conditions the temperature around the Earth might have been so high that methane would have disappeared. It would have broken down into high- molecular-mass carbon polymer-deposited on the Earth's surface, and hydrogen-escaping instantaneously into space. So an oxygen- free atmosphere on primitive Earth, if it existed, would probably have broken down in too short a time for a living system or chemicals of life to have formed in it." (Brooks, Jim [geochemist, former Vice-President, Geological Society]., "Origins of Life," Lion: Tring, Hertfordshire UK, 1985, pp.117-118) .
[top of page]"It was a Russian biochemist, A. I. Oparin, who in 1936 first suggested how inert chemicals might link together into an organic chain. Although it was impossible to create life from non-life in our present oxygen- heavy environment, he said (oxygen literally eats up any primitive organic chemical such as an amino acid), this might not have been the case in conditions billions of years ago. He suggested that there was a 'reducing' atmosphere - free of oxygen, and consisting of such gases as methane, ammonia, water and hydrogen. All experiments, including Stanley Miller's, have been based on this hypothesis. Without oxygen, there is no ozone canopy to protect Earth from the sun's ultraviolet rays. Nowadays, as established by NASA's early space probes, this canopy blankets us between fifteen and thirty miles above Earth's surface, effectively shielding us from certain death. So with oxygen in the air, the first amino acid would never have got started; without oxygen, it would have been wiped out by cosmic rays. Imaginative and elaborate solutions have been written to this conundrum. Perhaps the amino acid was formed at the edge of a volcano, and then sank into a lake where it dropped the few metres below the surface necessary to protect it from radiation; perhaps the Earth's waters were covered by a layer of tar-like chemicals which stopped ultraviolet light; perhaps the amino acid was protectively dehydrated or 'frozen' in some way on dry rock or clay, waiting for an improvement in the atmosphere. For every suggestion, there is a seemingly insuperable objection: beneath the surface of the water there would not be enough energy to activate further chemical reactions; water in any case inhibits the growth of more complex molecules; unlike conditions in laboratory experiments, the amino acids and their constituents could not be kept pure and isolated. In other words, the theoretical chances of getting through even this first and relatively easy stage in the evolution of life are forbidding." (Hitching, Francis, [Writer], "The Neck of the Giraffe: Or Where Dar
[top of page]"Further, it was supposed, simple organic molecules in the atmosphere, along with other more complex ones, would be expected to dissolve slowly in the newly formed oceans, creating a prebiotic soup. From this soup, it was hoped, life would somehow form spontaneously. This hypothesis continues to have many adherents, though it suffers from considerable difficulties. Chief among them is the fact that the soup would be extremely dilute. The rate of chemical reactions depends on how rapidly the reacting molecular species encounter one another-and that depends on how high their concentrations are. If the concentration of each is low, the chance that they will collide is very much lower. In a dilute prebiotic soup, reactions would be very slow indeed. A wonderful cartoon I recently saw captures this. It was entitled `The Origin of Life.' Dateline 3.874 billion years ago. Two amino acids drift close together at the base of a bleak rocky cliff; three seconds later, the two amino acids drift apart. About 4.12 million years later, two amino acids drift close to each other at the base of a primeval cliff.... Well Rome wasn't built in a day." (Kauffman, Stuart A. [Theoretical biologist, Santa Fe Institute, New Mexico, USA], "At Home in the Universe: The Search for Laws of Self-Organization and Complexity," [1995], Penguin: London, 1996, reprint, pp.34-35. Ellipses in original.).
[top of page]"And then what of the ' primitive soup' required for Chemical Evolution? If such an environment ever existed on Planet Earth for any appreciable time, it would require relatively large quantities of nitrogen- containing organic compounds (amino-acids, nucleic acid bases and so on). It is likely that such nitrogen- rich soups would have given significant quantities of 'nitrogenous cokes', trapped in various PreCambrian sediments. (The formation of such 'cokes' is the normal result obtained by heating organic matter rich in nitrogenous substances.) No such nitrogen-rich materials have yet been found in early Pre-Cambrian rocks on this planet. In fact the opposite seems to be true: the nitrogen content of early PreCambrian organic matter is relatively low (less than 0.15%). From this we can be reasonably certain that: there never was any substantial amount of 'primitive soup' on Earth when ancient PreCambrian sediments were formed; if such a 'soup' ever existed it was only for a brief period of time. Subtract from the basic concept of the Chemical Evolution Theory the ideas of substantial amounts of 'primitive soup' and a long period of time, and there is very little left." (Brooks, Jim [geochemist, former Vice-President, Geological Society]., "Origins of Life," Lion: Tring, Hertfordshire UK, 1985, p.118) .
[top of page]"Summarizing, one is left with ambivalent feelings. On the positive side, one is amazed by the ready formation of several biologically significant compounds, but it is discouraging that many important molecules resist prebiotic synthesis in acceptable quantities." (Maynard Smith, John [Emeritus Professor of Biology at the University of Sussex] & Szathmary, Eors [Institute for Advanced Study, Budapest], "The Major Transitions in Evolution," W.H. Freeman: Oxford UK, 1995, p.32).
[top of page]"The origin of sugars, including ribose, seems readily explicable by the prebiotic functioning of the formose reaction... In fact we are dealing here with a complex network of reactions, producing sugars from pre-existing sugars and formaldehyde.... There are two problems with this network that should be mentioned. First, the sugars formed are rather unstable, so, if they are to be present in significant amounts, this can only be in a steady state of formation and decay. It is imperative, therefore, that the end products of sugar decay be recycled to formaldehyde. Second, it is not at all obvious how ribose, among the more than 40 sugars could have been sufficiently prevalent under prebiotic conditions." (Maynard Smith, John [Emeritus Professor of Biology at the University of Sussex] & Szathmary, Eors [Institute for Advanced Study, Budapest, "The Major Transitions in Evolution," W.H. Freeman: Oxford UK, 1995, pp.30-31).
[top of page]"Sugars are particularly trying. While it is true that they form from formaldehyde solutions, these solutions have to be far more concentrated than would have been likely in primordial oceans. And the reaction is quite spoilt in practice by just about every possible sugar being made at the same time - and much else besides. Furthermore the conditions that form sugars also go on to destroy them. Sugars quickly make their own special kind of tar - caramel - and they make still more complicated mixtures if amino acids are around." (Cairns-Smith, A. Graham, [Reader in Chemistry, University of Glasgow], "Seven Clues to the Origin of Life: A Scientific Detective Story," Cambridge University Press: Cambridge UK, 1993, reprint, p.44).
[top of page]"But as researchers continue to examine the RNA-world concept closely, more problems emerge. How did RNA arise initially? RNA and its components are difficult to synthesize in a laboratory under the best of conditions, much less under plausible prebiotic ones. For example, the process by which one creates the sugar ribose, a key ingredient of RNA, also yields a host of other sugars that would inhibit RNA synthesis. Moreover, no one has yet come up with a satisfactory explanation of how phosphorus, which is a relatively rare substance in nature, became such a crucial ingredient in RNA (and DNA)." (Horgan, John [Senior Writer, Scientific American], "In The Beginning...," Scientific American, February 1991, p.103. Ellipses in original).
[top of page]"Setting aside the problem of the origin of ribose, the synthesis of nucleosides (base and sugar linked together as in present-day nucleotides) also poses problems. Purines react with ribose to yield the corresponding nucleosides in small amounts. The analogous reaction with pyrimidines seems hopeless. The phosphorylation of nucleosides to nucleotides can be done in dry- phase with relatively good yield, but all sorts of isomers with varying degrees of phosphorylation emerge. This lack of purity is important because accurate replication of a polymer depends on chemical purity." (Maynard Smith, John [Emeritus Professor of Biology at the University of Sussex] & Szathmary, Eors [Institute for Advanced Study, Budapest, "The Major Transitions in Evolution," W.H. Freeman: Oxford UK, 1995, pp.31-32).
[top of page]"Lipid formation again could have been preceded by the appearance of their constituents: fatty acids, glycerol and phosphate. While the abiogenic reaction between these three seems plausible, we have trouble with the formation of membranogenic lipids: no long-chain (C6-C18) linear (nonbranched) fatty acids have been synthesized in electric discharge reactions, although they would be indispensable for prebiotic membrane formation." (Maynard Smith, John [Emeritus Professor of Biology at the University of Sussex] & Szathmary, Eors [Institute for Advanced Study, Budapest], "The Major Transitions in Evolution," W.H. Freeman: Oxford UK, 1995, p.32).
[top of page]* Authors with an asterisk against their name are believed not to be evolutionists.
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