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Preformation


preformationism - 17th century theory of inheritance that hypothesized that all the organs of an adult were prefigured in miniature within either the sperm or the ovum.
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preformation The erroneous idea that gametes contain miniaturized versions of all of the elements present in an adult.
prehensile Adapted for grasping.
premating isolation When behaviors or other factors prevent animals from mating.
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Related Terms: Preformation
Theory that every germ cell contains the organism of its kind fully formed and that development involves merely an increase in size. Cf. epigenesis.
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Biological problem of today: preformation or epigenesis? The basis of a theory of organic development. W. Heinemann: London, 1896.
R. Jaenisch and A.
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"Biological problem of today: preformation or epigenesis? The basis of a theory of organic development". W. Heinemann: London, 1896.
Eva Jablonka and Marion J. Lamb. The Changing Concept of Epigenetics.
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(This contrasts with preformationism, which holds that the organism is already present in the gamete(s), merely growing and unfolding during development.) For example, ...
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