How did life begin? The answer from textbooks, most learned journals and the media directs our attention to a warm pool in the primitive earth, well-endowed with organic chemicals, from which the first self-replicating living thing spontaneously arose. If you want to see what it might have looked like - go to the Royal Botanic Gardens at Kew, London. Here is how John Lucas describes it (Weekend Telegraph, 1 July 1996):
`In the beginning was the raw material of life: rocks and boiling, bubbling
mud, small pools and puffs of subterranean steam ... all were features of
an unstable world. They help to set the stark scene of 4,000 million years
ago that greets you as you enter Evolution House.'
A modern advocate of this route to chemical evolution is Richard Dawkins. In his view, life is an amazingly lucky accident:
`...We go to a chemist and say...fill your head with formulae, and your
flasks with methane and ammonia and hydrogen and carbon dioxide and all
the other gases that a primeval nonliving planet can be expected to have;
cook them all up together; pass strokes of lightning through your simulated
atmospheres, and strokes of inspiration through your brain; bring all your
clever chemist's methods to bear, and give us your best chemist's estimate
of the probability that a typical planet will spontaneously generate a self-replicating
molecule. Or, to put it another way, how long would we have to wait before
random chemical events on the planet, random thermal jostling of atoms and
molecules, resulted in a self- replicating molecule? ... we'd have to wait
a long time by the standards of a human lifetime, but perhaps not all that
long by the standards of cosmological time....even if the chemist said that
we'd have to wait for a "miracle", have to wait a billion years - far longer
than the universe has existed, we can still accept this verdict with equanimity.
There are probably more than a billion available planets in the universe.
If each of them lasts as long as Earth, that gives us about a billion planet-years
to play with. That will do nicely! A miracle is translated into practical
politics by a multiplication sum.' (Dawkins, R., The Blind Watchmaker,
Penguin: London, 1991, page 145)
Modern theories of abiogenesis are traced back to the Russian biochemist Alexander Oparin who, in 1924, proposed a scheme of chemical evolution. Others picked up the theme: Haldane (1928), Bernal (1947) and Urey (1952). The latter's main contribution was to suggest an initial, hydrogen-rich, reducing atmosphere for the early earth.
Stanley Miller provided experimental data on the synthesis of organic materials which might be collected in a primeval pool. He worked initially (1952) with an atmosphere of methane, ammonia, hydrogen and water vapour (later experiments added other gases, notably carbon dioxide). Electrical discharges produced organic compounds. Numerous research investigations have taken place since Miller began, and in the products of the reaction, ten of the twenty amino acids found in living things have been synthesised naturally. Numerous other compounds were also detected, but these were not deemed so interesting as they do not occur in the proteins of life. It should perhaps be noted that these experiments have produced equal quantities of right-handed and left-handed organic molecules. This is quite different to the amino acids in living systems, where only left-handed molecules occur. The production of left-handed molecules is routine for living systems - but it is a fundamental problem to get them from a primeval soup.
Charles Darwin is often credited with having anticipated the modern chemical evolution scenario, based on ideas he expressed privately in a letter to Joseph Hooker in 1871.
`It is often said that all the conditions for the first production of a
living organism are now present, which could ever have been present. But
if (and oh! what a big if!) we could conceive in some warm little pond,
with all sorts of ammonia and phosphoric salts, light, heat, electricity,
&c., present, that a proteine (sic) compound was chemically formed ready
to undergo still more complex changes, at the present day such matter would
be instantly absorbed, which would not have been the case before living
creatures were found.'
`Darwin, bending somewhat to the religious biases of his time, posited in
the final paragraph of The Origin of Species that "the Creator" originally
breathed life "into a few forms or into one." Then evolution took over:
"From so simple a beginning endless forms most beautiful and most wonderful
have been, and are being evolved." In private correspondence, however, he
suggested life could have arisen through chemistry, "in some warm little
pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity,
etc. present".'(Orgel L.E., `The Origin of Life on the Earth',
Scientific American, October 1994, p.53).
`But the closing paragraph of The Origin of Species offered a sop
to the Christian tradition. There Darwin admits the possibility of a divine
origination of the first living cells from whence all else came.'(Henry
C.F.H., `Science and Religion', in Henry C.F.H., ed., Contemporary
Evangelical Thought: A Survey, Baker: Grand Rapids MI, 1968, p.253)
1. There is no evidence for an early earth with a reducing atmosphere. The consensus now is that the early atmosphere was neutral: composed of carbon dioxide, nitrogen, water and perhaps 1% hydrogen. There is a strong case to be made for the presence of oxygen also. The neutral atmosphere makes the stability of organic molecules a matter of doubt - they would be degraded and lost very quickly.
2. Results from revised Miller-type experiments are quite different. With a neutral atmosphere of water, nitrogen and carbon dioxide, the reaction products are ammonia and nitric acid. Using the most favourable mix of gases, the yield is only about 0.01% amino acid, almost all lysine.
3. Biogenic carbon (derived from living cells) has been detected in the earliest rocks yet discovered in the earth -so there is no record of a time when life was not present! (This is why the date of 4,000 million years was used by John Lucas in his report of the Kew exhibition - there are no rocks known of this age). The origin of life has to be pushed back to where no data is available to constrain models.
Thaxton, Bradley & Olsen have a chapter entitled `The Myth of the Prebiotic Soup' in their book: The Mystery of Life's Origin. This summarises the evidence for the statements given above.
`Based on the foregoing geochemical assessment, we conclude that both in
the atmosphere and in the various water basins of the primitive earth, many
destructive interactions would have so vastly diminished, if not altogether
consumed, essential precursor chemicals, that chemical evolution rates would
have been negligible. The soup would have been too dilute for direct polymerization
to occur. Even local ponds for concentrating soup ingredients would have
met with the same problem. Furthermore, no geological evidence indicates
an organic soup, even a small organic pond, ever existed on this planet.
It is becoming clear that however life began on earth, the usually conceived
notion that life emerged from an oceanic soup of organic chemicals is a
most implausible hypothesis. We may therefore with fairness call this scenario
"the myth of the prebiotic soup."' (Thaxton, C.B., Bradley, W.L.
& Olsen, R.L., The Mystery of Life's Origin: Reassessing Current
Theories, Lewis & Stanley: Dallas TX, 1992, p.66).
The naturalist rejects intelligent causation - but this explanation is exactly what Christians have come to expect from their reading of the Bible. The creation approach to origins explains why the earth carries evidence of life from its earliest history.
David J. Tyler (1996)