Theory Of Preformation:-
It is an ancient theory to explain the development of organism. According to this theory the miniature of the adult animal including human being is preformed and contains either in the ovum or sperm of the organism.
A group of biologist like Haller, Bannet, Malpigian believes that the ovum contains a transparence highly folded very small and unobservable miniature of the adult animals. These who believes this idea were know as ovist. The other groups leaded by Leeuwenhoek and heartseeker believes that preformed miniature organism to be present in the head of sperm but not in the ovum and is called Animal cule.
These scientists are called Animal culist, so this group believes that the sperm is the seed and the ovum is the soil in which the seed was planted these 2views are know as Preformation theories as both of these group believes that the human being fully formed and reside in a miniature form in the sperm or the ovum.
In parthenogenesis, the egg develop in to the animal without the assistant of spermatozoa. If the egg can devlop the embryo can not be preformed inside the spermatozoa. However this theory was not atole accepted.
The Preformation theories persistence up to the 18th century wolff showed both sperm and ovum for the development of the individual and there was no miniature for the development full formed either in the sperm or in the ovum thus a Preformation theory atole accepted.