preformation

We are almost back again with the problem of preformation, but in a modern form.

These early flowering plants always form their flowers in the previous season, called preformation.

His rejection of preformation was on philosophical and experimental grounds.

Then there is the preformation (12-14 years), comprising some thirty young people, as regards training for its players 14 to 18 years.

Preformation of the blade by percussion flaking.

He thus defined the preformation/ epigenesis controversy.

For him preformation was 'one of the greatest triumphs of rational over sensual conviction'.

The Preformation (feat.

The early nineteenth century saw major developments in embryology, which challenged the mechanical concept of generation and overthrew the preformation theory.

A new method to estimate the preformation probability as a penetrability of the internal part of the barrier within a fission theory was developed.

She was published in the Stanford Encyclopedia of Philosophy on "Epigenesis and Preformation".

His discoveries helped to illuminate philosophical arguments surrounding the topics of emboîtment, pre-existence, preformation, epigenesis, and metamorphosis.

Contrary to Kant's position, the preformation theory avoids skepticism about the nature of the noumenal world (Kant believed that the real world is unknowable).

In a fission theory the preformation probability is the penetrability of the internal part of the barrier from the initial turning point R to the touching point R.

This dispatched the theory of preformation and gave some support to the concept of a morphogenetic field, a concept of which Spemann learned from Paul Alfred Weiss.

As microscopy improved during the 19th century, biologists could see that embryos took shape in a series of progressive steps, and epigenesis displaced preformation as the favoured explanation among embryologists.

Preformation theory is a theistic epistemological theory that states that knowledge is possible only because God has endowed humans with certain innate ideas along with dispositions or aptitudes in certain ways.

Consequently, the preformation of suitably protected dipeptide derivatives of the type FMOC-Xaa1-Oxa/THz-OH is preferable for use in peptide synthesis.

This important refutation of both preformation and the mosaic theory of Wilhelm Roux was to be subject to much discussion in the ensuing years, and caused friction among Driesch, Roux and Haeckel.

Others, including Thomas Hunt Morgan and Oscar Hertwig, attempted to separate the two cells, for the matter was of great importance, particularly to the arguments between proponents of epigenesis and preformation, but satisfactory results could not be achieved.

When the Frenchman, Charles Bonnet, was confronted with the argument that if preformation were true the first rabbit would have had to contain 10 10000 preformed embryos, he merely responded by saying that it was always possible, by adding zeros, to crush the imagination under the weight of numbers.

Hans Driesch separated the individual cells of a 2-cell sea urchin embryo and shows that each cell develops into a complete individual, thus disproving the theory of preformation and showing that each cell is "totipotent," containing all the hereditary information necessary to form an individual.