The Beginnings of Life on Earth
A Cosmic Imperative
I have tried here to review some of the facts and ideas that are being considered to account for the early stages in the spontaneous emergence of life on earth. How much of the hypothetical mechanisms considered will stand the test of time is not known. But one affirmation can safely be made, regardless of the actual nature of the processes that generated life. These processes must have been highly deterministic. In other words, these processes were inevitable under the conditions that existed on the prebiotic earth. Furthermore, these processes are bound to occur similarly wherever and whenever similar conditions obtain. This must be so because the processes are chemical and are therefore ruled by the deterministic laws that govern chemical reactions and make them reproducible.
It also seems likely that life would arise anywhere similar conditions are found because many successive steps are involved. A single, freak, highly improbable event can conceivably happen. Many highly improbable events—drawing
a winning lottery number or the distribution of playing cards in a hand of bridge—happen all the time. But a string of improbable events—the same lottery number being drawn twice, or the same bridge hand being dealt twice
in a row—does not happen naturally.
All of which leads me to conclude that life is an obligatory manifestation of matter, bound to arise where conditions are appropriate. Unfortunately, available technology does not allow us to find out how many sites offer appropriate conditions in our galaxy, let alone in the universe. According to most experts who have considered the problem—notably, in relation with the Search for Extraterrestrial Intelligence project—there should be plenty of such sites, perhaps as many as one million per galaxy. If these experts are right, and if I am correct, there must be about as many foci of life in the universe. Life is a cosmic imperative. The universe is awash with
- de Duve, C. 1991. Blueprint for a Cell: The Nature and Origin of Life. Burlington, N.C.: Neil Patterson Publishers, Carolina Biological Supply Company.
- de Duve, C. 1995. Vital Dust: Life as a Cosmic Imperative. New York:Basic Books.
- Gilbert, W. 1986. The RNA World. Nature 319: 618.
- Gilbert, W. 1987. The exon theory of genes. Cold Spring Harbor Symposium on Quantative Biology 52: 901-905.
- Keefe, A. D., G. L. Newton and S. L. Miller. 1995. A possible prebiotic synthesis of pantetheine, a precursor of coenzyme A. Nature 373:683-685.
- Miller, S. L. 1953. A production of amino acids under possible primitive earth conditions. Science 117: 528-529.
- Noller, H. F, V. Hoffarth and L. Zimniak. 1992. Unusual resistance of peptidyl transferase to protein extraction procedures. Science 256: 1416-1419.
- Schopf, J. W. 1992. The oldest fossils and what they mean. In Major Events in the History of Life, ed. J. W. Schopf. Boston: Jones and Bartlett, pp. 29-63.
- Schopf, J. W. 1993. Microfossils of the early Archaean apex chert: new evidence of the antiquity of life. Science 260: 640-646.