Figure 1

The Benard instability. Establishing an increasing vertical temperature gradient (ΔT) across a thin layer of liquid leads to heat transfer through the layer by conduction (organizational state #1). Exceeding a certain critical value of temperature gradient (ΔT_C) leads to an organizational state transition within the liquid layer. As a result of the transition, conduction is replaced by convection (organizational state #2) and the rate of heat transfer through the layer increases in a stepwise manner. Organizational state #2 (convection) is a more ordered state (higher negative entropy) than organizational state #1 (conduction). The more ordered state requires and, at the same time, supports a higher rate of energy/matter flow through the system. For this reason, the transitions between organizational states in nonequilibrium systems tend to be all-or-none phenomena. As a consequence, nonequilibrium systems are inherently quantal, absorbing and releasing energy/matter as packets. Organizational state #2 (convection) will relax into organizational state #1 (conduction) upon decreasing the temperature gradient (not shown). The Benard instability is an example of a nonequilibrium system illustrating a number of universal self-organizational processes shared by all nonequilibrium systems, including living cells and organisms (see discussion in the text). Reproduced from [8].