Evolution.

Society for Experimental Biology

Date:: 1953

Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Evolution. Source: Wellcome Collection.

27/484 (page 3)

THE ORIGIN OF LIFE 3 would lead to the settling of the elements and compounds which are solid or liquid at the highest temperatures—carbon, metallic carbides, silicates and water in approximately that order, leading to the first appearance of carbon compounds in reduced form (Oparin, 1938). Alternatively, and more commonly, it is supposed that the primitive atmosphere contained carbon dioxide, but Jones (1950) finds grounds for thinking that this first atmosphere may have been blown off the face of the planet at the high temperatures resulting from the 'green-house' effect of an atmosphere of carbon dioxide, which is transparent to light but not to heat. It seems to be impossible on geochemical evidence to find even a starting point for the discussion. With this measure of disagreement about the initial conditions from which any synthesis of organic molecules must have started, it may be felt to be a hopeless task to seek for any understanding of the origin of the peculiar chemical systems which occur in living organisms. The subject can, however, be approached in a different way by focusing attention less on the organic and inorganic chemical aspects of the problem, and more on the dynamic aspects—on the processes involved in life rather than on the substances in which we see the processes at work in biochemical labora¬ tories. In simpler chemical systems the study of processes falls within the domain of physical chemistry, and the object of this paper is to try to relate the phenomenon of evolution to physical and physico-chemical processes which can safely be assumed to have been at work before anything which could be called 'life' appeared on the earth's surface. The basic thesis is broadly this—that the phenomenon of evolution is a general type of process, some of whose characteristics can now be defined in a sufiiciently precise way for them to be identified in organic chemical and even in inorganic and physical systems ; and that just as we suppose the course of evolution of living organisms to have been continuous from the simpler to the more complex forms of life, so the extrapolation can be pushed further back, beyond the point at which coherent organisms first appeared, into the realm of the chemical evolution of matter and (though that is hardly relevant here) perhaps even beyond that to the evolution of planets, of elements and even of ultimate particles. II. THE EVOLUTIONARY PROCESS The idea of a continuous form-building process at work throughout the history of matter and not merely during the biological phase is not, of course, new. It is almost inherent in any attempt to argue intelligently about the origin of anything, whether it be life, the solar system or matter itself. The fundamental concept was stated clearly by Herbert Spencer 1-2