Thermodynamic Foundations of Life Sciences
Author: Avshalom C. Elitzur

Thermodynamic Foundations of Life Sciences

A. C. Elitzur
Guest lectures: U. Alon, E. Cohen, A. Horwitz, Y. Pilpel, S. Safran, A. Yonath

Thermodynamics studies energy transformations and entropy changes across the entire realm of micro- and macroscopic processes. Entropy's probabilistic measure, given by statistical mechanics, turns out to be equally useful for measuring information and complexity, revealing the affinity between the three. As such, thermodynamic laws are independent of the system's specific chemistry or types of energies involved. This ubiquity makes thermodynamics a powerful framework for studying all organic processes, even where the system's specific details are not accessible.

We begin with introducing the concepts of energy, work and entropy. The laws of thermodynamics are then explained. Energy's various types and transformations are presented, and energy conservation, dictated by the First Law, is demonstrated. Next, illustrated by Carnot's cycle, comes the non-conserved quantity, namely, entropy. The Second Law is thus introduced. Entropy is studied by all its manifestations and measures: probability, disorder, irreversibility, heat, etc. Students are urged to explore their differences and overlaps until comprehending all of them, both intuitively and mathematically. We next proceed to the concepts of information and complexity, shown to be hallmarks of all living systems. With the aid of "Maxwell's Demon" paradox, their thermodynamic measures are shown to follow from those of entropy.

The energy-information tradeoff thus serves as an introduction to the course's second part. Basic biological notions are introduced from evolutionary theory, population genetics, nanotechnology and environmental sciences, showing how their entropy, information content and complexity can be measured with predictive power for other biological measures. Critical discussion of open questions, fallacies and misuses of thermodynamics are added. We conclude with pointing out further possible applications of thermodynamics to life sciences.

Guest lecturers will illuminate these topics from the viewpoints of their disciplines.

Students will be graded by the final examination based on class material as well as articles and textbooks. An option is given to prepare a home-assignment instead of 50% of the exam.

Upon finishing this course you should be able to:

  1. Trace energy input, output, processing and transformations within a living system and show how energy is conserved.
  2. Show that entropy along these transformations is not conserved, understanding what it takes for it to increase/decrease.
  3. Comprehend, both mathematically and intuitively, the affinities and tradeoffs between energy, entropy, information and complexity.
  4. Assess the role and importance of all the above phenomena in biological processes.


  1. Di Cera, E., Ed. (2000) Thermodynamics in Biology. Oxford: Oxford University Press.
  2. Dill, K.A., & Bromberg, S. (2003) Molecular Driving Forces: Statistical Thermodynamics in Chemistry and Biology. New York: Garland Science.
  3. Edsall, J. T., & Gutfreund, H. (1983). Biothermodynamics: The Study of Biochemical Processes at Equilibrium. Chichester, West Sussex: Wiley.
  4. Elitzur, A. C. (1996) Life’s emergence is not an axiom: A reply to Yockey. J. Theor. Biol., 180, 175-180.
  5. Fanchon, E., Neori, K-H., & Elitzur, A.C. (2011) What does Maxwell's demon select, and how? In Ben-Menahem, Y. & Hemmo, M. [Eds.] Probability in Physics: Essays in Memory of Itamar Pitowsky. New York: Springer, 135-148.
  6. Frenkiel-Krispin, D. & Minsky A. (2002) Biocrystallization: A last-resort survival strategy in bacteria. ASM NEWS 68: 277-283
  7. Gordon, G., & Elitzur, A.C. (2009) The ski-lift pathway: Thermodynamically unique, biologically ubiquitous. Preprint.
  8. Haynie, Donald T. (2001) Biological Thermodynamics. Cambridge: Cambridge University Press.
  9. Kittel C. & Kroemer H. (2000) Thermal Physics. San-Francisco: Freeman and Co., Ch. 8, pp 225-259.
  10. Landau L.D. & Lifshitz E.M. (1980) Course of Theoretical Physics Volume 5: Statistical Physics, Part 1, third edition revised and enlarged, Oxford: Pergamon Press, Ch.1-2, pp. 1-78.
  11. Leff, H. S., & Rex, A. F. (2003) Maxwell’s Demon 2: Entropy, Classical and Quantum Information, Computing. Bristol: Institute of Physics Publishing.
  12. Minsky A, Shimoni E, Frenkiel-Krispin D. (2002) Stress, order and survival. Nat. Rev. Mol. Cell Biol. 3: 50-60.
  13. Nelson, P. (2004) Biological Physics. NY: Freeman.
  14. Zotin, A. I. (1990). Thermodynamic Bases of Biological Processes: Physiological Reactions and Adaptations. New York: Walter de Gruyter.