1 - Thermodynamics and Living Systems

Abstract

This book examines complex biotic systems such as organisms, ecological systems, and the Earth in light of the principle of thermodynamics, especially the Second Law. (The First Law is discussed in appendix.) Thermodynamics is adequate for the study of macroscopic objects without equivocal and nondefinitive results inherent in many studies of reductionistic viewpoints. At the core of the Second Law of Thermodynamics is the entropy concept. However, entropy itself cannot be measured and calculated for biological systems, even for very small organisms. Contrarily, process variables, entropy flow, and entropy production can be quantified by the use of energetic data and physical methods. To hold to the Second Law, entropy production should be positive for open systems, as shown by Prigogine. This book examines entropy productions for biological organisms, ecological systems, and the Earth, and it shows that numerically they are all positive and hence that the Second Law is valid for these systems. Thus, Maxwell’s demon, a hypothetical agent that violates the Second Law, does not exist for these systems, and they cannot be perpetual-motion machines of the second kind. Net entropy that flows into biotic systems turn out to be negative, showing the validity of the concept of negative entropy in the context of Schrödinger.