Preformation theory - pre-mendelian theory, Biology

Preformation Theory (1632-1723)

(i)         Scientist 'Malpighi Swammerdam' propounded the preformation theory. This theory holds that the sex cells (sperm and ova) had the miniature copy of adults and the development of embryo was actually only the enlargement of parts that were already present in the sperm or egg.

(ii)         This miniature form of the animal present in the gamete was called 'Homunculus'.

(iii)        This theory was supported by Hartsoeker.

(iv)        Those who considered homunculus to be present is sperms were called Spermist.

(v)         Leeuwenhoek & Hartsoeker believed that miniature of organism was present in the head of the sperm.

(vi)        Those who considered homunculus to be present in ova (eggs) were called Ovist.

(vii)        The term preformation covers the both.

(viii)       Malpighi, Swammerdam & Bonnet believed that miniature organism was present in the egg.

Posted Date: 10/10/2012 3:19:39 AM | Location : United States







Related Discussions:- Preformation theory - pre-mendelian theory, Assignment Help, Ask Question on Preformation theory - pre-mendelian theory, Get Answer, Expert's Help, Preformation theory - pre-mendelian theory Discussions

Write discussion on Preformation theory - pre-mendelian theory
Your posts are moderated
Related Questions
Define the effect of SCFA on Sodium Absorption? SCFAs (short chain fatty acids) have a stimulatory effect on sodium absorption from colonic lumen. The unionized SCFA crosses th

Q. As per the Watson - Crick Model how many polynucleotide chains does a DNA molecule have? The DNA molecule is formed by two polynucleotide chains bound in antiparallel mode (

Types of Cleavage a) Radial Type : If each of the blastomeres of upper tier lies exactly over the corresponding blastomeres of the lower tier the pattern of cleavage is radia

CHEMICA L COMPOSITION OF CHROMATIN Chromatin threads composed of DNA (31 %), RNA (2-5%) and proteins (Histon-36%, Non histon 28%). Histone and protamines are basic prote

What is Tetralogy of Fallot ? Figure: Anatomical location of tetralogy of fallot Indications for Surgery :  The diagnosis of tetralogy is considered as an indicatio

What is the difference between the alpha helix and the beta-sheet protein conformations? Ans) Alpha helix and beta-sheet conformations are the two major types of secondary struc

Q. Explain about Treatment and Management of Dyslipidemia? Maintenance of blood lipids within the normal range is the most essential objective to prevent the onset/progression

how the structure of ciliates facilitates their parasitism

When we watch animals in the wild, most often we see them foraging for food. The foraging behaviour of animals has been a focus of behavioural studies for many decades. Natura

Explain the Procedure for Morphological Study of Fungi? Now carry out the exercise, following the steps enumerated herewith: 1. Prepare a humid chamber by placing two-three