Theory of embryology - pre-formation theory, Biology

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PRE FORMATION THEORY -

Proposed by Marcello Malpighi.
Studied chick egg and proposed his work in "De ova-incubato".
According this different part of embryo previously present in the eggs. These parts developed through the growth.
Swammerdam proposed that the sex cell contain preformed emrbyo or a more or a less perfect miniature of the adult.
Ovists view - This theory was supported by Malpighi, Spallanzani, Haller, Bonnet and swammerdam. These scientists belived that miniature organism was present in the eggs were called ovist.
Spermist view - Leeuwenhoek and Hartsoeker believed that miniature of organism was present in the head of sperm. This miniature is called hommunculus in man and animalcule in other animals.

1978_miniature of sperm.png

Miniature in Mammalian Sperm

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