# Punctuated Equilibrium > **Machine-Evolution Nexus:** [[articles/Digital Darwinism and the Invisible World of Machine Evolution|Digital Darwinism and the Invisible World of Machine Evolution]] places this node within the history and governance of substrate-independent evolution. **Domain:** Evolution / Paleontology **Doc Type:** Canonical Wiki Node **Maturity:** Developed ## Definition Punctuated equilibrium is a model of evolutionary tempo in which species often show long intervals of relative morphological stability interrupted by geologically rapid change associated with speciation. ## Nexus Context Barricelli’s early artificial populations reportedly displayed long stasis followed by abrupt lineage replacement, a formal resemblance to the pattern Eldredge and Gould later described from fossils. ## Evidence Boundary The theory does not claim instantaneous creation, universal stasis or rejection of natural selection. Digital resemblance does not establish historical influence. ## Relationships [[wiki/Niles Eldredge|Niles Eldredge]], [[wiki/Stephen Jay Gould|Stephen Jay Gould]], [[wiki/Fossil Record|Fossil Record]], [[wiki/Nils Aall Barricelli|Nils Aall Barricelli]] ## Sources / Provenance - Eldredge and Gould (1972); IAS Barricelli archive.