New Theory On Nature Of Organic Life

Press, Volume CVIII, Issue 31763, 21 August 1968, Page 17

New Theory On Nature Of Organic Life

(By

ROBERT C. COWEN.

natural science editor of the “Christian Science Monitor’’)

A decade of discovery has forced scientists to take a new view of the fundamental nature of organic life.

Once, they marvelled that anything so materially complex could arise from simple chemicals. Only chance and infrequent changes, taking place over billions of years, would allow this to happen, they thought.

Now they know better. In standing in awe of biochemistry, they were, to quote Dr Richard Lemmon, “being amazed at the inevitable, at the way things naturally are.”

Like others who study the origin of earthly life, the University of California chemist bases his view on laboratory experience as well as on theory. He and others have found how some natural materials, such as a clay, may act as catalysts to speed the build-up of complex organic molecules from simpler forms. They have seen how these complicated molecules naturally take the shapes they need for life processes. A protein molecule, for example, is a long chain of thousands of sub-units called amino acids. To be biologically active, this chain has to fold up in one particular way and in no other. Natural Tendency Scientists have realised for some time that the primitive earth, a rather common type of new planet, would be rich in simple organic chemicals. These should include amino acids. The “miracle” of organic life, to them, lay in the build-up, from these simple chemicals, of large molecules that have to have very specific compositions and shapes to do their job.

This, Dr Lemmon said in discussing it recently, is just what scientists should have expected to happen. “A few years ago,” he explained, “we all saw calculations showing it would take a long time to make somethink so beautifully complex as a protein. The fact of the matter is, in nature or in the laboratory, a chain of amino acids has a natural tendency to assume just those forms we see in nature. This comes from residual electrical forces which make the chains take particular shapes rather than random forms. “Also, among individual amino acids, some tend more readily than others to form chains. These seem to be the ones most abundant in living systems." “Life," he added, “is a likely thing, certainly. I know of few in the field who don’t think it likely now.

Life “Inevitable”

“Given a ‘soup’ of amino acids (like the early oceans), the emergence of life is virtually inevitable. This is only a theory, only a notion. But I think it is a good one. “Ten years ago, we didn’t know enough about these tendencies for certain amino acids to form chains and the chains spontaneously to assume certain forms. There has been a gradual dawning that this is the case. It is one of the biggest conclusions to come out

of research into the origin of life.”

The conclusion has helped chemists like Dr Lemmon adjust their theories to the fact that life on earth simply didn’t have billions of years to get going. Discoveries of palaeobotanists, especially of Professor Elso S. Barghoorn, of Harvard University, show that organic life was a going concern very early in earth's history. Evidence In Fossils Dr Barghoorn and others have found fossil evidence of bacteria and algae in the oldest rocks yet known. These rocks are part of the Fig Tree cherts of South Africa which date from 3.1 billion years ago. Bacteria or algae already represent fairly advanced life forms. They are as far ahead of the first living systems as modem plants are advanced beyond these one-celled forms. There must have been a fairly long evolutionary period during which the early bacteria arose. Since the solid earth dates to only 4.5 billion years ago, this leaves less than a billion years for the rise of its first life forms. Realising this, and aware of the chemical discoveries Dr Lemmon described, Dr Barghoom said this spring that the rise of organic life must be a highly probable and geologically rapid event. “I say this flatly,” he remarked, “given the proper temperatures, and given water and carbon and nitrogen in some form (that is, conditions of the primitive earth) then life is almost inevitable. This represents a very profound change in philosophical outlook for palaeontology.” Limited Views One of the world's great chemists, and a Nobel prize winner. Dr Harold Urey, of the University of California, I feels scientists have been blinded by their own limited views in thinking about organic life. He has observed: “I think those who have made the most extensive study of the very complicated chemistry of living organisms are those who are most amazed that life could have evolved at all. But in coming to this emotional conclusion, I think there are features of the natural process we do not appreciate. . . . “We have no concept as to what can happen in a million years. We have no concept as to how large an ocean is and what an enormous amount of experimentation can take place in a large body of water over long periods of time. Clues Gathered 1 "It seems to me that it may be that life originated even during the time before one could definitely say that the accumulation of the earth was complete ... say 100 million years or possibly even less." Dr Lemmon agrees with such a short time scale. He explained: "If the right catalysts came together, the rise of life might have happened in one year. I see no reason, certainly, to feel crowded with 100 million years.” In trying to reconstruct possible ways this may have happened, chemists have some clues. But they still have a long way to go. They can produce amino acids and other simple life-related chemicals under primitiveearth conditions. But they have yet to link up more than a few amino acids into chains in the laboratory. They have yet to reproduce a plausible chemical route by which earthly life may have arisen. Intellectual Game This doesn’t discourage the researchers. Dr Lemmon and his colleagues have little doubt that such a scheme will be worked out eventually. Even then, he says, scientists won’t know if it is the right one. “You must realise that this whole origin-of-life research is just an intellectual game,” he said. “The human race is never going to know the answers definitely enough to say ‘This is how it was done.’ It will only be able to say ‘Here’s a likely way to do it.' And we won’t even be able to do this in our life time.

“As mankind becomes more sophisticated about science, it will realise that hard-and-fast answers don’t exist. Only probabilities exist It's Important that people know science is more this kind of effort to assess probabilities than it is a search for absolute truth.”

Manager's Certificate.—The hotel mentioned during the hearing of Mr Duncan Weir's application for a hotel manager’s certificate was the Lyttelton Hotel and not the British Hotel as was reported in “The Press” yesterday. The i error is regretted.

Natural scientists once thought organic life was so unlikely it could arise only after billions of years of slow evolution. Now they believe its appearance would be fast and virtually inevitable on any favourable planet This, the first of two articles, reports the change in viewpoint.