What is "caenogenesis"

Kenogenesis \Ken`o*gen"e*sis\, n. [Gr. ? new + E. genesis.] (Biol.) Modified evolution, in which nonprimitive characters make their appearance in consequence of a secondary adaptation of the embryo to the peculiar conditions of its environment; -- distinguished from palingenesis. [Written also cenogenesis and c[ae]nogenesis.]

cenogenesis \cen`o*gen"e*sis\ n. [Gr. ? new + E. genesis.] (Biol.) The introduction during embryonic development of characters or structure not present in the earlier evolutionary history of the strain or species (as addition of the placenta in mammalian evolution); a modified evolution, in which nonprimitive characters make their appearance in consequence of a secondary adaptation of the embryo to the peculiar conditions of its environment; -- distinguished from palingenesis. [Also spelled caenogenesis and formerly kenogenesis.]

alt. (context biology English) The embryotic development of cross-species structures or characteristics. n. (context biology English) The embryotic development of cross-species structures or characteristics.

n. introduction during embryonic development of characters or structure not present in the earlier evolutionary history of the strain or species (as addition of the placenta in mammalian evolution) [syn: cenogenesis, kenogenesis, cainogenesis, kainogenesis] [ant: palingenesis]

Caenogenesis (also variously spelled cainogenesis, cenogenesis, kainogenesis, kenogenesis) is the introduction during embryonic development of characters or structure not present in the earlier evolutionary history of the strain or species, as opposed to palingenesis. Notable examples include the addition of the placenta in mammals.

Caenogenesis constitutes a violation to Ernst Haeckel's biogenetic law and was explained by Haeckel as adaptation to the peculiar conditions of the organism's individual development. Other authorities, such as Wilhelm His, Sr., on the contrary saw embryonic differences as precursors to adult differences.