# Differential Reproductive Success > **Machine-Evolution Nexus:** [[articles/Digital Darwinism and the Invisible World of Machine Evolution|Digital Darwinism and the Invisible World of Machine Evolution]] places this concept within the history and governance of substrate-independent evolution. **Domain:** Evolution / Selection **Doc Type:** Canonical Wiki Node **Maturity:** Developed ## Definition Differential reproductive success occurs when variants leave unequal numbers of viable descendants because their heritable characteristics interact differently with an environment. ## Machine-Evolution Context It is the selection term that turns variation and heredity into Darwinian population change. In digital ecologies, access to CPU time, memory or space can change reproductive rates. ## Continuity and Evidence Boundary Persistence without reproduction may produce cultural or market selection, but the stricter Darwinian claim requires an identified descendant-generating process. ## Relationships [[wiki/Natural Selection|Natural Selection]], [[wiki/Fitness Landscape|Fitness Landscape]], [[wiki/Resource Constraint|Resource Constraint]], [[wiki/Digital Population|Digital Population]] ## Sources / Provenance - Darwinian and population-genetic definitions of fitness and selection.