Punctuated equilibrium

[[Complex systems]] exist in punctuated equilibrium, repeatedly [[evolution | 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 [[evolution | 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