For each book I buy, I try to find at least one quote in it to add to my quotes database (i.e. Unclassified Quotes) and from there to be selected in my 1,000 best quotes for my "Evolution Quotes Book".
[Above (click to enlarge): Genome map of Mycoplasma genitalium, the simplest living cell (with a genome of `only' 580,070 base pairs!), but which however is a parasite that cannot survive apart from its host- us, so it is not the true minimum cell for a free-living organism.
The latter would be more like the "1.66-megabase pair genome sequence of" the primitive free-living bacterium, Methanococcus jannaschii" with its "total of 1738 ... protein-coding genes" (Science, 23 August 1996) and which the late Colin Patterson considered was "close to the minimum necessary for independent life" (see `tagline' quote at end)!
Above (click to enlarge): Genome map of Methanococcus jannaschii. Both graphics from BacMap, University of Alberta.]
This quote is by the late William H. Thorpe (1902-1986) was Professor of Animal Ethnology at Cambridge University, and a pioneering animal behaviourist. He was also a Darwinist and a theist, but I gather Thorpe's was the limited god of the process theology of Alfred North Whitehead rather than the omnipotent and omniscient God of Christianity.
However, regarding the "origin of living matter from nonliving," to his credit Thorpe admitted that "The crux of the whole problem" is not just "to explain how the ... building blocks of living organisms, might have been formed on earth" (although that is problem enough!) but how "to envisage the origin of the cell" "which reduplicates itself, leaving offspring," bearing in mind that "All the cells that we know are of fantastic complexity" (my emphasis):
"In recent years there has been a spate of speculation about the possible origin of living matter from nonliving. Many ingenious and not unreasonable hypotheses have been proposed during its early history when water was condensing to make rivers and oceans, and when we might suppose that here and there rich solutions and suspensions of a variety of chemicals might have enabled interaction with sunlight to set in train, by lucky accident, the first steps leading to the birth of life. Many of these suggestions are plausible and indeed attractive; but even supposing them to be true, the `life' that we can conceive of as being formed in this way could, it seems, have been only something of the general type which we can loosely call viruses. Now, important though this could have been, it is of limited help in envisaging the origin of life as we now know it. The `life' which might have been formed in this so-called `primeval soup' has yet to be linked to life which reduplicates itself, leaving offspring to carry on the race. The crux of the whole problem, as we understand it, is to envisage the origin of the cell; for all the life which we now study, from bacteria to man, is cellular in almost all its stages. As we have already seen, the cell is a chemical `laboratory' of immense complexity. The cell itself could not possibly function without the cell membranes which contain and selectively isolate the working parts of this laboratory. Biologists have long hoped to find a really `primitive' cell illustrative of the stages between the supposed primitive acellular life and life as we know it now. But there seems little doubt today that there are no primitive cells living on the earth. All the cells that we know are of fantastic complexity. I believe that no biologist or physicist has yet been able to propose even the outlines of a theory as to how such a cell might have been `evolved'. Monod himself sees that the evolution of even the simplest cell `presents herculean problems' [Monod, J., "Chance and Necessity," Penguin: London, 1997, p.143]." (Thorpe, W. H., "Purpose in a World of Chance: A Biologist's View," Oxford University Press: Oxford UK, 1978, p.20).
Stephen E. Jones, BSc (Biol).
"In July 1995 the entire DNA sequence of the bacterium Haemophilus influenzae, 1.8 million base-pairs, was elucidated, followed three months later by the sequence of a second parasitic bacterium. In April 1996 the complete sequence (12 million base-pairs) of yeast was announced, and in August 1996 the first complete sequence of a free-living bacterium, Methanococcus, which has 1.7 million base-pairs and about 1700 genes, perhaps close to the minimum necessary for independent life." (Patterson, C., "Evolution," [1978], Cornell University Press: Ithaca NY, Second Edition, 1999, p.23)
Posts
No comments:
Post a Comment