preformation

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pre·for·ma·tion

(prē′fôr-mā′shən)

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.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

preformation

(ˌpriːfɔːˈmeɪʃən)

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

Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

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

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Noun

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 of preformation

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"

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preformazione

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References in periodicals archive ?

(75) For more on preformation, see Bowler (1982), especially 60-62.

Skepticism concerning causality: an evolutionary epistemological perspective

Reimbursements of preformation capital expenditures.

IRS issues disguised sale guidance

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.

Accounting for book-tax differences of property contributed to a partnership

Egg and Sperm and Preformation (University of Chicago Press, 1997) and which, also unfortunately, includes his own unpublished master's thesis!

The Life Sciences in Eighteenth-Century French Thought

preformation, generatio aequivoca, and epigenesis) concerning the generation and development of organisms.

Skepticism concerning causality: an evolutionary epistemological perspective

Another debate concerned whether embryos exhibited essential structure from the outset (preformation) or whether their structure developed only gradually, varying with context (epigenesis).

Monsters & the tyranny of normality: how do biologists interpret anomalous forms?

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.

Dickens and Heredity: When Like Begets Like

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.

Laib veut partir

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."