Self-Organized Criticality and Punctuated Equilibria

TL;DR

This paper discusses how many natural systems exhibit punctuated equilibria, evolving through critical states that cause intermittent bursts of activity, which are essential for the development of complex phenomena.

Contribution

It links punctuated equilibria to self-organized criticality and reviews simple models illustrating this behavior in dynamical systems.

Findings

Systems tend to evolve towards critical states.

Intermittent bursts of activity are characteristic of such systems.

Punctuated equilibria enable systems to remember past states while evolving.

Abstract

Many natural phenomena evolve intermittently, with periods of tranquillity interrupted by bursts of activity, rather than following a smooth gradual path. Examples include earthquakes, volcanic eruptions, solar flares, gamma-ray bursts, and biological evolution. Stephen Jay Gould and Niles Eldredge have coined the term "punctuated equilibria" for this behavior. We argue that punctuated equilibria reflects the tendency of dynamical systems to evolve towards a critical state, and review recent work on simple models. A good metaphoric picture is one where the systems are temporarily trapped in valleys of deformable, interacting landscapes. Similarities with spin glasses are pointed out. Punctuated equilibria are essential for the emergence of complex phenomena. The periods of stasis allow the system to remember its past history; yet the intermittent events permit further change.