preformation

(redirected from preformationists)
Also found in: Dictionary, Thesaurus, Encyclopedia.
Related to preformationists: Preformation 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.

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.

preformation

[-fôrmā′shən]
Etymology: L, prae + formatio, formation
an early theory in embryology in which the organism is contained in minute and complete form within the germ cell and after fertilization grows from microscopic to normal size. Compare epigenesis.

preformation

(prē-fawr-mā′shŭn)
In embryology, the development of structures from pre-existing templates, e.g., of bones from cartilage templates.
References in periodicals archive ?
Like the ancients, the preformationists assigned the father this role, and they pointed to the active, swimming sperm as the vehicle for placing the new being inside the passive mother.
Preformationists believed that the little being inside the sperm "develop[ed] in the mother just as the seed does in the field.
Female inferiority continued to function as an axiom to justify preformationist theory.