- Biology. the theory that an embryo develops from the successive differentiation of an originally undifferentiated structure (opposed to preformation).
- Genetics. the approximately stepwise process by which genetic information is modified and translated into the substance and behavior of an organism.See also epigenetics.
- Geology. ore deposition subsequent to the original formation of the enclosing country rock.
- the widely accepted theory that an individual animal or plant develops by the gradual differentiation and elaboration of a fertilized egg cellCompare preformation (def. 2)
- the formation or alteration of rocks after the surrounding rock has been formed
- alteration of the mineral composition of a rock by external agents: a type of metamorphism
- The theory that an individual is developed by successive differentiation of an unstructured egg rather than by a simple enlarging of a preformed entity.