# Major Evolutionary Transitions > **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 / Organizational Change **Doc Type:** Canonical Wiki Node **Maturity:** Developed ## Definition Major evolutionary transitions are changes in which independently reproducing units become integrated into a new higher-level unit of heredity, cooperation and selection. ## Nexus Context Examples include chromosomes, eukaryotic cells and multicellular organisms. The 2026 evolvable-AI paper asks whether interacting AI systems could participate in another substrate and unit transition. ## Evidence Boundary The label requires more than increasing capability or dependence. Reproduction, conflict mediation, inheritance and a changed unit of selection must be shown. ## Relationships [[wiki/Unit of Selection|Unit of Selection]], [[wiki/Eörs Szathmáry|Eörs Szathmáry]], [[wiki/John Maynard Smith|John Maynard Smith]], [[wiki/Evolvable AI|Evolvable AI]] ## Sources / Provenance - Maynard Smith and Szathmáry, _The Major Transitions in Evolution_ (1995); PNAS (2026).