[Equilibrium thermodynamics of quasi-closed biological systems. Cell differentiation and development of organisms]

The law of temporal hierarchies makes it possible to identify quasi-closed systems in open biological systems and to use the approaches of hierarchical quasi-equilibrium thermodynamics to establish the direction of ontogenesis and evolutionary processes. A short review of the achievements in the field of evolution biological thermodynamics and the thermodynamics of aging are presented. Cell differentiation, the development of multicell organisms, and the emergence of the structures of the higher hierarchies of the biological world are assumed to be determined by the thermodynamic direction of these processes. Cell organisms contain identical genes. Only some of them, however, function in the course of differentiation and development. Gene induction and repression during differentiation are determined by the position of newly emerging cells, whose properties depend on their functional position. These properties are determined by thermodynamic parameters of the cells' environment (thermostat), whose components and physicochemical characteristics affect gene induction and repression. A holographic (three-dimensional) design of the future organism (higher structures of the biological world) is determined by the thermodynamic demand for certain genes. The latter's operation is stimulated by their environment. One of the well-known examples that corroborates the presented model is the change of gene transcription when the nature of lipids and other metabolites contained in cells are changed. Application of the principle of stability of matter to the structures of adjacent hierarchies constitutes additional proof that quasi-equilibrium thermodynamics can be applied to the biological systems of the real world.