LIMITATIONS ON PREBIOLOGICAL SYNTHESIS

Chemical evolution toward life would have involved a series of spontaneous reactions, and thus, by definition, non-equilibrium conditions. External energy inputs would have been needed to maintain such conditions. The concentrations of interesting intermediates like formaldehyde, hydrogen cyanide, amino acids and organic phosphates in such a system would have depended on the balance between synthesis under the influence of the energy sources and degradation in the universal approach to equilibrium. A look at possible energy sources in the primitive environment of the earth indicates that they could have furnished enough energy to maintain only very small concentrations of intermediates. Concentrations would have been highest at low temperatures because of slower degradation of the compounds produced. A primary requirement for continuous chemical evolution is the availability of means to couple incoming energy into specific synthetic pathways. © 1969 Academic Press Inc. (London) Ltd. All rights reserved.