Complex systems exist in punctuated equilibrium, repeatedly evolving through distinct phases of randomness, growth, consolidation, and collapse.
Phase 1, Randomness: the system is unstructured. Randomness 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 catalyses other innovations in a positive feedback loop.
Phase 3, Consolidation: growth rates saturate. The ecosystem consolidates into a highly organised network, optimised for efficiency as each agents seeks to eye 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.