Punctuated equilibrium

Complex systems exist in punctuated equilibrium, repeatedly evolving through distinct phases of randomness, growth, consolidation, and collapse.

(Phase 1) Random: The system is unstructured. Random events occur without particularly changing the structure.

(Phase 2) Growth: An innovation causes a major phase transition within the structure of the system. The innovation catalyzes other innovations in a positive feedback loop.

(Phase 3) Consolidation: Growth rates saturate. The ecosystem consolidates into a highly organized network, optimized for efficiency, as each agent seeks to eke out as much as it can from its position in the value chain. Hubs (keystone species) appear at critical points.

(Phase 4) Collapse: A random shock, or new innovation demolishes one of the keystone species, causing cascade failure within the highly structured network. The ecosystem collapses into a random structure.

(Repeat): The system begins a slow crawl back up the evolutionary ladder toward a new metastable state.

Insights from the work of Sanjay Jain, Sandeep Krishna:

• Large extinctions in an evolutionary model: The role of innovation and keystone species
• A model for the emergence of cooperation, interdependence, and structure in evolving networks