Thermodynamics of Biological Growth

Abstract

ACCORDING to some recent opinions, living organisms are nearer to open systems in the thermodynamic sense than to classical closed systems, although an organism plus its environment constitute a system which must be regarded as closed. While closed systems eventually reach equilibria characterized by minimum Gibbs free energy and maximum entropy, Prigogine¹ and de Groot² have predicted that open systems will approach steady states of minimum entropy production. On this basis, Prigogine and Wiame³ have inferred that living organisms grow towards a state of minimum metabolism per unit mass, but this view and other discussions⁴ on this theme are subject to two criticisms. On one hand, the theorem of minimum entropy production holds only for open systems very near to the steady state⁵ and, on the other, it has never been tested experimentally for living organisms so that conclusions derived from it are weakened to some extent.