Second, a steady state of an ORN can evolve toward highly ordered structures. Indeed, a steady state is stabilized through a full balance between the irreversible reaction and diffusion processes but it is a dynamic non-equilibrium state and is always forced to approach equilibrium. Therefore, the steady state should soon move toward equilibrium when such a possibility is introduced through interaction with the environment. Note here that this argument means that an approach of a steady state of an ORN to equilibrium occurs only in a part of an ORN in which such an approach is possible. If we consider the aforementioned ORN formed near the bottom of a small, long pore in a mineral precipitate in the vicinity of a hydrothermal vent in a deep sea as an example, the inflows or outflows of chemical substances are expected to make almost no contribution to an approach of a steady state of an ORN to equilibrium, except a passive contribution resulting from a change in the concentrations of chemical substances in an ORN, because the rate constants of these processes will be kept nearly constant. Thus, a remaining possibility of an approach of a steady state of an ORN to equilibrium is a change in reactions in an ORN.