Caenogenesis (also variously spelled 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
Palingenesis (; also palingenesia) is a concept of rebirth or re-creation, used in various contexts in philosophy, theology, politics, and biology. Its meaning stems from Greek , meaning 'again', and , meaning 'birth'.
In biology, it is anothe ...
.
Notable examples include the addition of the
placenta in
mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s.
Caenogenesis constitutes a violation to
Ernst Haeckel
Ernst Heinrich Philipp August Haeckel (; 16 February 1834 – 9 August 1919) was a German zoologist, naturalist, eugenicist, philosopher, physician, professor, marine biologist and artist. He discovered, described and named thousands of new sp ...
's
biogenetic law
The theory of recapitulation, also called the biogenetic law or embryological parallelism—often expressed using Ernst Haeckel's phrase "ontogeny recapitulates phylogeny"—is a historical hypothesis that the development of the embryo of an ani ...
and was explained by Haeckel as adaptation to the peculiar conditions of the
organism's individual development. Other authorities, such as
Wilhelm His, Sr.
__NOTOC__
Wilhelm His Sr. (9 July 1831 – 1 May 1904) was a Swiss anatomist and professor who invented the microtome. By treating animal flesh with acids and salts to harden it and then slicing it very thinly with the microtome, scientists were ...
, on the contrary saw embryonic differences as precursors to adult differences.
See also
*
Ontogeny
*
Recapitulation theory
References
Bibliography
Gould, S.J. 1977. Ontogeny and Phylogeny. Cambridge: Harvard University Press.
Developmental biology
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