Development that lets a system adapt, or grow, from less well adapted to its requirement to more well adapted. Perhaps (straining the metaphor) to be contrasted with UniqueCreationDevelopment.
ED would seem to be largely orthogonal to IncrementalDelivery. But EvolutionaryDelivery maybe suggests otherwise (to my muddled early morning brain) --KeithBraithwaite
See also OrganicSimplicity.