Wolff had risen up as an opponent of the so-called preformation theory, still widespread at that time, according to which the entire plant with all its different parts is already present in embryonic physical form in the seed, and simply grows out into space through physical enlargement. From Wordnik.com. [Man or Matter] Reference
I think that it is interesting that Behe has toyed with the idea of a kind of preformation of the DNA, with the genes for such-and-such being designed into the genome at the beginning and remaining hidden over the generations until they were expressed. nickmatzke. From Wordnik.com. [The true origin of "intelligent design" - The Panda's Thumb] Reference
Specification of the primordial germ cells (PGCs) takes place via different strategies across animal phyla; either specified early in embryogenesis by the inheritance of maternal determinants in the cytoplasm of the oocyte ( 'preformation') or selected later in embryonic development from undifferentiated precursors by a localized inductive signal ( 'epigenesis'). From Wordnik.com. [BioMed Central - Latest articles] Reference
The eighteenth-century preformation - ists, of whom Spallanzani was one and his friend. From Wordnik.com. [GENETIC CONTINUITY] Reference
In this respect it is like its predecessor, the theory of preformation of the eighteenth century. From Wordnik.com. [Epigenesis and Preformationism] Reference
The argument appears in an early form as an argument against embryonic development, and in favor of preformation. From Wordnik.com. [The true origin of "intelligent design" - The Panda's Thumb] Reference
Epigenesis and preformation offer two competing interpretations of what is involved, with a range of alternatives in between. From Wordnik.com. [Epigenesis and Preformationism] Reference
The first Scholion is directed against the theory of preformation, and succeeds in refuting it on the ground of simple observation. From Wordnik.com. [Form and Function A Contribution to the History of Animal Morphology] Reference
Yet typically discussions of epigenesis and preformation have focused on individual organisms and their development rather than on species. From Wordnik.com. [Epigenesis and Preformationism] Reference
Thus, discussions of epigenesis and preformation often bring in other ancillary questions and are difficult to separate from their contexts. From Wordnik.com. [Epigenesis and Preformationism] Reference
Nature or nurture, epigenesis or preformation, genetic determinism or developmental free will, or is some version of a middle ground possible?. From Wordnik.com. [Epigenesis and Preformationism] Reference
Epigenesis: the doctrine of growth from an undifferentiated germ, as opposed to preformation, which implies development from already existing rudiments. From Wordnik.com. [Explanation of Terms Used in Entomology] Reference
Furthermore some authors saw epigenesis or preformation as entirely internally directed, while others in each case allowed responses to the environment. From Wordnik.com. [Epigenesis and Preformationism] Reference
Generation and growth were on his view, mechanical processes, for, according to the doctrine of preformation, which he shared with Malebranche, generation is just growth. From Wordnik.com. [Kant and Leibniz] Reference
A miniature, fully formed individual believed by adherents of the early biological theory of preformation to be present in the sperm cell. gosh that's funny. previous - next. From Wordnik.com. [sneezers Diary Entry] Reference
Pangenesis would have been obscured in the great debate that followed between epigenesis preformation had it not been for Maupertius and Buffon in the second half of the century. From Wordnik.com. [Dictionary of the History of Ideas] Reference
These questions, various answers to which constitute the theories of preformation or epigenesis, were lifted out of the realm of speculation up into that of an exact science when first Wilhelm Roux and then Hans Driesch used experimental methods in their research into development. From Wordnik.com. [Hans Spemann - Nobel Lecture] Reference
Whitman felt that what biology needed was a clear statement of the alternative views, and then movement to a new standpoint examining how much depends on the organism's developmental response to external conditions drawing on preformation, rather than on programmed internal unfolding alone. From Wordnik.com. [Epigenesis and Preformationism] Reference
Moreover, he sees, especially in those stages which caused the physical development of man, and which became the material basis of his spiritual productions, moments of development which cannot be explained by natural selection or by a coincidence of material circumstances, but only by the preformation of the body after a certain design and for a certain purpose. From Wordnik.com. [The Theories of Darwin and Their Relation to Philosophy, Religion, and Morality] Reference
In modified form the preformation theory dominated the biology of the eighteenth century. From Wordnik.com. [Physiology or Medicine 1933 - Presentation Speech] Reference
Though not quite so crude as these early notions, the views of men like Weismann are really reducible to preformation. From Wordnik.com. [The Catholic Encyclopedia, Volume 9: Laprade-Mass Liturgy] Reference
In this connection it may be observed that Dr. Darwin emphatically opposes the preformation views of Haller and Bonnet in these words. From Wordnik.com. [Lamarck, the Founder of Evolution His Life and Work] Reference
According to the advocates of preformation or predelineation, the growth of the embryo was merely the expansion or evolution of a miniature organism. From Wordnik.com. [The Catholic Encyclopedia, Volume 9: Laprade-Mass Liturgy] Reference
There are some other details, I suppose, but right now we should spend some time on preformation and acquired characters, which I suppose are equivalent theories. From Wordnik.com. [Pharyngula] Reference
If we accept the idea that characters are represented by particular parts of the chromosomes, according to Morgan's scheme, our theory of development is the modern form of the theory of preformation. From Wordnik.com. [Hormones and Heredity] Reference
The truth is that biological processes are not within our powers of conception as those of physics and chemistry are, and Bateson's hypothesis is nothing but the old theory of preformation in ontogeny. From Wordnik.com. [Hormones and Heredity] Reference
At the time, the "preformation theory" was probably the most widely accepted -- i.e., that the adult form exists in miniature in the egg or germ, development being merely an unfolding of these preformed parts. From Wordnik.com. [Taboo and Genetics A Study of the Biological, Sociological and Psychological Foundation of the Family] Reference
Bonnet more or less modified the latter in his later writings, and, at length, he admits that a "germ" need not be an actual miniature of the organism; but that it may be merely an "original preformation" capable of producing the latter. From Wordnik.com. [Darwiniana : Essays — Volume 02] Reference
From this point of view the process, which, in its superficial aspect, is epigenesis, appears in essence, to be evolution, in the modified sense adopted in Bonnet's later writings; and development is merely the expansion of a potential organism or "original preformation" according to fixed laws. From Wordnik.com. [Darwiniana : Essays — Volume 02] Reference
20th, a time when a balance of epigenesis and preformation seemed likely, a time for a bit of predeterminism and a bit of cellular free will. From Wordnik.com. [Epigenesis and Preformationism] Reference
| | Opposed preformation | |. From Wordnik.com. [Lamarck, the Founder of Evolution His Life and Work] Reference
| preformation | characters. | | of acquired. From Wordnik.com. [Lamarck, the Founder of Evolution His Life and Work] Reference
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