preformation

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Related to Preformationism: Germ-Plasm Theory

pre·for·ma·tion the·o·ry

archaic theory that the embryo was fully formed in miniature within a gamete at the time of conception.
See also: homunculus. Compare: epigenesis.
Farlex Partner Medical Dictionary © Farlex 2012

preformation

(prē′fôr-mā′shən)
n.
1. The act of shaping or forming in advance; prior formation.
2. A theory popular in the 1700s that all parts of an organism exist completely formed in the germ cell and develop only by increasing in size.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

preformation

(prē-fawr-mā′shŭn)
In embryology, the development of structures from pre-existing templates, e.g., of bones from cartilage templates.
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
"Preformationism," Gould says he learned in school, "was a nonsensical doctrine espoused by men who could not bear to give up the dream of a static world order ruled by an omnipotent God--and who therefore could not admit the plain evidence of their senses when watching the development of the chick in the egg."
(70) Conrad Hal Waddington's coining of the term 'epigenetics' took into account aspects of both 'preformationism' and 'epigenesis', synthesizing them together.
This is a principle which the materialisms, pangenesis and preformationism, do not comprehend.
Aristotle will have more arguments to offer in book 2 against preformationism, the view that an animalcule or homunculus is transferred from the father and planted in the mother's body, with her functions being strictly incubation and feeding.(23) His mention of it at this point (722b5), however, permits us to note that preformationism had been employed in Greek cultural life to deny women any role in generation, and consequently to deny them any significant connection with their children and any connection of their children with them.
Aristotle's opposition to preformationism is not founded on the grounds that it demeans women's part in generation.
Some of Aristotle's feminist critics have misread him on this fundamental issue, mistaking Aristotle's theory for a version of preformationism, and hence they have assigned to him the sexist consequences of that theory.
Recall that he rejected preformationism on just such grounds: How could the father's body supply the sex-specific body parts for female offspring?