Some Modern
Speculations
George Wald, "Fitness of the Universe," Origins
of Life, Vol. 5, 1974, p. 26.
In this strange paper I have ventured to suggest that natural selection
of a sort has extended even beyond the elements, to determine the properties of protons
and electrons. Curious as that seems, it is a possibility worth weighing against the only
alternative I can imagine, Eddington's suggestion that God is a mathematical physicist. It
is the old biological problem of supernatural creation as against `spontaneous--i.e.,
natural--generation'. Back of the spontaneous generation of life under other conditions
than now obtain upon this planet, there occurred a spontaneous generation of elements of
the kind that still goes on in the stars; and back of that I suppose a spontaneous
generation of elementary particles under circumstances still to be fathomed, that ended in
giving them the properties that alone make possible the universe we know.
Isaac Asimov, Science Digest, Vol. 69, April
1971, p. 69.
Where did the substance of the universe come from? ...If 0 = +1 + (-1),
then something which is 0 might just as well become 1 and -1. Perhaps in an infinite sea
of nothingness, globs of positive and negative energy in equal-sized pairs are constantly
forming, and after passing through evolutionary changes, combining once more and
vanishing. We are in one of these globs in the period of time between nothing and nothing,
and wondering about it.
Robert Ardrey, Territorial Imperative (Athenium
Publishers, New York, 1966), p. 280.
...The [prairie dog] kiss came about, I should assume, as a means of
identification in the dark recesses of one's burrow to make sure by proper flavor that no
stranger has sneaked in. Whatever its origin or selective value may be, whenever the
members of a coterie meet, they exchanger what is very nearly a human kiss, open-mouthed,
and they seem to enjoy it.
Libbie Henrietta Hyman, Invertebrates: Protozoa
Through Ctenophora (McGraw-Hill, New York, 1940), p. 252.
The gastraea theory of Haeckel won acceptance at the time and has since
been promulgated in practically every textbook of zoology and embryology. It and its
corollaries represent a masterly simplification of the embryologic and phylogenetic
history of animals and furnish a clear and plausible explanation of the stages by which
complex metazoan structure might have been achieved. But it is probably one of those
simplifications that too beautiful to be true.
Theodosius Dobzhansky, "Changing Man," Science,
Vol. 155, 27 Jan. 1967, p. 409.
...Evolution is not predestined to promote always the good and the
beautiful. Nevertheless, evolution is a process which has produced life from non-life,
which has brought forth man from an animal, and which may conceivably continue doing
remarkable things in the future. In giving rise to man, the evolutionary process has,
apparently for the first and only time in the history of the Cosmos, become conscious of
itself. This opens at least a possibility that evolution may some day be directed by man,
and that the prevalence of the absurd may be cut down.
Leslie E. Orgel, The Origins of Life: Molecules and
Natural Selection (John Wiley & Sons, New York, 1973), pp. 230-231.
The major intellectual problem presented by the origins of life is
concerned with the next stage, the evolution of biological organization. How did a complex
self-replicating organism evolve from an unorganized mixture of polymeric molecules?
Little experiment evidence is available, so one is forced to attempt a speculative
reconstruction of this phase in the origins of life.
The key to the understanding of the evolution of biological organization
is the theory of natural selection. Before the evolution of complicated self-replicating
organisms, natural selection must have acted on something much simpler, probably on
polymeric molecules resembling nucleic acids. It is believed that nucleic acid-like
molecules were formed in the prebiotic soup and were able to reproduce without the help of
enzymes. The theory of natural selection then shows that those molecules that could
replicate fastest would have become dominant in the prebiotic soup.
As the competition became fiercer, the more successful
families of self-replicating molecules must have "learned" to
make use of small molecules in their environment to help them to replicate
even faster. The most important of these
adaptations involved the amino acids; ultimately a family of self-replicating
nucleic acids evolved to the point where they could begin to control
the synthesis of polypeptide
sequences that had useful catalytic properties. This adaptation led ultimately
to the evolution of protein synthesis and the genetic code.
The evolution of protein synthesis is not understood in detail. One of
the great challenges of the problem of the origins of life is to demonstrate in the
laboratory how polynucleotides, without the help of preformed enzymes, could have
replicated and begun to control the synthesis of peptides with determined sequences. Once
this has been done we shall be well on our way to understanding the origins of the first
living cells.
Stanley Miller and Leslie Orgel, The Origins of Life
on the Earth (Prentice-Hall, Englewood Cliffs, N.J., 1974), pp. 33-52.
Chapter Four. The Composition of the Primitive Atmosphere
Geological and geophysical evidence is insufficient to allow us to state
with any precision what conditions were like on the surface of the primitive earth.
Arguments concerning the composition of the primitive atmosphere are particularly
controversial. It is important, therefore, to state our own prejudice clearly. We believe
that there must have been a period when the earth's atmosphere was reducing, because the
synthesis of compounds of biological interest takes place only under reducing conditions.
There is...some..evidence...none of it is conclusive. ...It is at least
possible. ...Fortunately, everyone agrees...
(p. 34)...it probably would occur... (p. 38)...if we
assume... (p. 39)...we suppose...assumes... If...would be...must have
been... We assume... If...must
have been...two further assumptions...assumption... ...we have supposed...
...we have assumed... We are not certain that either assumption is
correct for the primitive earth.
However, we believe...that is, we believe... (p. 41)...It seems reasonable...
If so...must have controlled... (p. 42)...if...must have been... ...so
we cannot be sure...However...we
think it likely... ...We assume... ...arbitrarily...and we suppose... (p.
43)...we again assume... ...additional assumption... (p. 44)...assumption...since
we think... It may...
...assume... If we make the more realistic assumption... Since we assumed...
(p. 45)...it is not likely... ...if...would... Presumably it could
have been...provided...
...unlikely...could have... ...must have involved... ...hence, we believe...
We believe... (p. 46)...would not have been... ...might have occurred...the
proposal... ...supposed to
have been formed... ...would have...would precipitate... ...would have
accumulated... ...would be... ...would absorb... We think... This could
have been... (p. 47)...could
have... ...would have...if... ...it seems likely... There could have been...
...if we are prepared to assume... (p. 48)...If we assume... ...seems
reasonable... ...if we assume...
...would undoubtedly (p. 49)...would probably not... However, we think...might
have been... ...not unreasonable. ...would have led... ...a number
of
assumptions...assumption... ...may have evolved...tentative. ...must have
been... ...would have been... It is generally believed... (p. 50)...Beyond
the fact that there was no
oxygen in the primitive atmosphere[Remember that on page 33 the authors
said that this was their "prejudice."]...there is little
agreement... ...could have been...or as high as...(or even outside
these bounds). ...may have been... ...must have been... ...may
not be... ...may have been... ...probably... ...probably...could have been...or
it could have been much more. ...may have been... ...would have...
...would then have...which would
have... (p. 51)...It is also possible... It probably requires... ...supposing...or
by assuming... ...may imply... On the other hand, it may not. ...may
have... We may,
therefore, feel confident... There is clearly a wide range of choices of
intermediate models. (p. 52)...These models have all assumed... It
is also...possible... The reader may
wish to construct his own scenario for the time course of development of
O2 in the atmosphere.
Editor's note: We do not mean in
any way to ridicule the excellent publication by Professors Miller and Orgel from which
the above expressions were extracted, for we consider it to be one of the best and
certainly the most honest and discerning books on the subject of abiogenesis theories
written from the evolutionary perspective. However, the language they are forced to use by
their own scientific objectivity and honesty clearly reveals the indefinite, misty,
slippery character of the hypotheses and data which they must handle.
|