preformation


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Related to preformation: Preformation theory

pre·for·ma·tion

 (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.

preformation

(ˌpriːfɔːˈmeɪʃən)
n
1. the act of forming in advance; previous formation
2. (Biology) biology the theory, now discredited, that an individual develops by simple enlargement of a fully differentiated egg cell. Compare epigenesis1

pre•for•ma•tion

(ˌpri fɔrˈmeɪ ʃən)

n.
1. previous formation.
2. a former biological theory that the individual preexists fully formed in the germ cell and grows from microscopic to normal proportions during the embryo phase.
[1725–35]

preformation

the theory that germ cells contain every part of the future organism in miniature form, future development being only a matter of increase in size. Cf. epigenesis.
See also: Biology
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.preformation - a theory (popular in the 18th century and now discredited) that an individual develops by simple enlargement of a tiny fully formed organism (a homunculus) that exists in the germ cell
theory - a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; "theories can incorporate facts and laws and tested hypotheses"; "true in fact and theory"
Translations
References in periodicals archive ?
(75) For more on preformation, see Bowler (1982), especially 60-62.
Describing how this new scientific paradigm can reshape our present sense of what Romanticism--and particularly Romantic poetry--is, Gigante draws upon an analogy proposed by Helmut Muller-Sievers, who suggested in 1997 that "the multifacted inquiry into the phenomena of life at this time placed the biological concepts of preformation and epigenesis 'in the same relation to each other as allegory and symbol,'" and that the struggle between them haunts us today (33).
Reimbursements of preformation capital expenditures.
1.704-3(c)(2)(iii) are allocations and distributions of operating cash flow, certain preferred returns and guaranteed payments, and reimbursements of certain preformation expenditures.
Egg and Sperm and Preformation (University of Chicago Press, 1997) and which, also unfortunately, includes his own unpublished master's thesis!
preformation, generatio aequivoca, and epigenesis) concerning the generation and development of organisms.
Another debate concerned whether embryos exhibited essential structure from the outset (preformation) or whether their structure developed only gradually, varying with context (epigenesis).
Amongst the scientific theories, she points to preformation, blended heredity, and reproduction as being pertinent to Dickens's work, and, in the area of cultural beliefs, she highlights the models of heredity advanced by classical Greece and the ancient Hebrews.
Il y a eu plusieurs acquis: une equipe jeune et competitive, un centre de preformation qui va bientot demarrer, et un stade equipe desormais d'un systeme d'eclairage[beaucoup plus grand que], a-t-il souligne.
(37.) The mention of preformation in PJ suggests that Godwin was at least partially aware of the debate in biology between preformation and epigenesis begun in 1759 by embryologist Caspar Friedrich Wolff.
The NAIB recommends that those selling ownership interests in risk retention groups should be specifically exempted from a requirement to be a licensed securities broker-dealer and specifying that all preformation promotional activities are covered by securities law exemptions."
They reveal no cumulative abnormal return for either the preformation sub-period or the post-formation one.