End-directed evolution and the emergence of energy-seeking behavior in a complex system.

Self-organization in a voltage-driven nonequilibrium system, consisting of conducting beads immersed in a viscous medium, gives rise to a dynamic tree structure that exhibits wormlike motion. The complex motion of the beads driven by the applied field, the dipole-dipole interaction between the beads and the hydrodynamic flow of the viscous medium, results in a time evolution of the tree structure towards states of lower resistance or higher dissipation and thus higher rates of entropy production. Thus emerges a remarkably organismlike energy-seeking behavior. The dynamic tree structure draws the energy needed to form and maintain its structure, moves to positions at which it receives more energy, and avoids conditions that lower available energy. It also is able to restore its structure when damaged, i.e., it is self-healing. The emergence of energy-seeking behavior in a nonliving complex system that is extremely simple in its construct is unexpected. Along with the property of self-healing, this system, in a rudimentary way, exhibits properties that are analogous to those we observe in living organisms. Thermodynamically, the observed diverse behavior can be characterized as end-directed evolution to states of higher rates of entropy production.