preformation
/priːfɔːˈmeɪʃ(ə)n
/noun [mass noun]
1The action or process of preforming something.The classification also encompasses physiological processes that are underlying phenomena of preformation and neoformation....
- Moreover, information concerning both the co-occurrence of preformation and neoformation within the same shoot system is virtually non-existent.
- If ‘seeing is believing,’ most still wanted to believe in preformation, and so they convinced themselves that they saw little men and tiny animals when they peered into their microscopes.
1.1 Biology, historical The theory, now discarded, that an embryo develops from a complete miniature version of the organism. Often contrasted with epigenesis.Accordingly, near the turn of this century, many biologists who espoused or contested theories of evolution, meant, among other things, to support or undermine theories of the preformation of species according to a developmental plan....
- Each in turn examined the theory of preformation in the light of natural philosophy and religion.
- Development could not therefore be based on preformation but must be epigenetic, because during development many new cells are generated by division from the egg, and new types of cell are formed.
Derivatives
preformationist
- We should not accuse the preformationists of stupidity for placing the right idea into the wrong substance.
- In the first chapter, ‘Genesis of the gene,’ Moss traces the emergence of the modern conception of the gene back to the 18th century debate between preformationists and epigeneticists.
- Yet other preformationists believed that the sperm contained the embryo and some even claimed to be able to see a tiny human - a homunculus - in the head of each human sperm.