SELF-ORGANIZED CRITICALITY IN LIVING SYSTEMS

We suggest that ensembles of self-replicating entities such as biological systems naturally evolve to a self-organized critical state in which fluctuations, as well as waiting times between phase transitions (''epochs''),are distributed according to a 1/f(alpha) power law. Such distributions can explain observed frequency distributions in extinction events as well as fractal population structures, and support the punctuated equilibrium picture of evolution. We demonstrate these concepts by analyzing a population of coexisting self-replicating strings (segments of computer code) subject to mutation and survival of the fittest, which constitutes an artificial living system.