Preformation theory - pre-mendelian theory, Biology

Assignment Help:

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.


Related Discussions:- Preformation theory - pre-mendelian theory

Specific considerations and applied aspects in dentistry, Specific consider...

Specific considerations and applied aspects in dentistry The dental chair and delivery system. The chair should be smooth and seamless. The greatest potential for cross contami

What is echocardiography, Q. What is Echocardiography? Ans. Echoca...

Q. What is Echocardiography? Ans. Echocardiography has become an established and powerful tool for diagnosing presence of CAD and defining its consequence. It can help in

Hmp shunt in erythrocytes, HMP shunt in erythrocytes HMP shunt in eryth...

HMP shunt in erythrocytes HMP shunt in erythrocytes is of importance due to the generation of NADPH, which maintains the glutathione (G-SH)  in  the reduced  state by  glutathi

What are the fat requirements of athletes, What are the Fat Requirements of...

What are the Fat Requirements of athletes? Fats are the body's other major energy source. It  is  a  well  known  fact  that fat  is  a highly concentrated source of energy

Determine requirement of trace elements for infant, Determine Requirement o...

Determine Requirement of Trace elements for Infant? Most elements, such as zinc and iodine, hold a major significance in infant nutrition. Zinc is associated with growth while

What are the main components of the cytoskeleton, The cytoskeleton is a net...

The cytoskeleton is a network of very little tubules and filaments spread throughout the cytoplasm of eukaryotic cells. It is made of microtubules, microfilaments and intermediate

Defina about the lipid metabolism, Defina about the Lipid Metabolism? A...

Defina about the Lipid Metabolism? Animal studies consistently show a hypotriglyceridenlic effect although equivocal results have been seen with healthy humans. Hypotriglycerid

Explain the term health, Explain the term 'health' Mention any two ways of ...

Explain the term 'health' Mention any two ways of maintaining it. Why does a doctor administer tetanus antitoxin and not a tetanus vaccine to a child Injured in a roadside acci

Explain economic status of diet, Economic Status Economic Status  :  I...

Economic Status Economic Status  :  It is one of the important practical considerations to be kept in mind while  formulating  a diet prescription. During  an acute illness, a

What are the elements that constitute the internal ear, Q. What are the ele...

Q. What are the elements that constitute the internal ear? What are the functions of those structures? In the internal ear there are the semicircular canals and the cochlea. Th

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd