International Journal of Astrobiology

Research Article

Why did life emerge?

Arto Annilaa1 and Erkki Annilaa2

a1 Department of Physics, Institute of Biotechnology and Department of Biosciences, POB 64, University of Helsinki, Finland e-mail:

a2 Finnish Forest Research Institute, Finland


Many mechanisms, functions and structures of life have been unraveled. However, the fundamental driving force that propelled chemical evolution and led to life has remained obscure. The second law of thermodynamics, written as an equation of motion, reveals that elemental abiotic matter evolves from the equilibrium via chemical reactions that couple to external energy towards complex biotic non-equilibrium systems. Each time a new mechanism of energy transduction emerges, e.g., by random variation in syntheses, evolution prompts by punctuation and settles to a stasis when the accessed free energy has been consumed. The evolutionary course towards an increasingly larger energy transduction system accumulates a diversity of energy transduction mechanisms, i.e. species. The rate of entropy increase is identified as the fitness criterion among the diverse mechanisms, which places the theory of evolution by natural selection on the fundamental thermodynamic principle with no demarcation line between inanimate and animate.

(Received April 06 2008)

(Accepted September 26 2008)