Epimorphosis

epimorphosis [‚ep·ə′mȯr·fə·səs]

(physiology)

Regeneration in which cell proliferation precedes differentiation.

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Epimorphosis 

(1) Direct postembryonic development of animals whose larvae lack larval organs and differ little from adults. Epimorphosis is the opposite of indirect postembryonic development, or metamorphosis.

(2) A method of regeneration in animals by which the part of an organism or organ surviving after an injury becomes whole without substantial reorganization, as a result of growth and tissue differentiation at the wound surface. Epimorphosis occurs in many invertebrates, such as planarians and annelid worms, as well as in fish, amphibians, and reptiles, whose tails and extremities are capable of regenerating.

(3) A term (in Russian, epimorfoz) introduced by I. I. Shmal’gauzen in 1939 to designate the transition from biological evolution, that is, adaptation to environmental conditions, to social evolution, to dominance over the environment. Epimorphosis has occurred just once as an evolutionary trend in the history of the biosphere, that is, when as a result of the development of the brain and second signaling system man’s arms were no longer needed for locomotion.