preformationist
Preformationism is a historical doctrine in biology and embryology that holds that an organism exists in miniature within a reproductive cell or within the egg, and that development is essentially the enlargement of this preformed entity rather than the growth and differentiation of undifferentiated tissues.
The theory emerged in the 17th century with the advent of microscopy and sparked a major debate
Over time, preformationism faced increasing criticism as embryology advanced. Beginning in the mid-18th century, advocates of
Today, preformationism is regarded as a historical episode in the history of science. It is cited as