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

fat digestion requires two steps, Fat digestion requires two steps? What a...

Fat digestion requires two steps? What are the steps and what enzymes are used to accomplish each step?

Extracted chlorophyll pigments, Extracted chlorophyll pigments If we...

Extracted chlorophyll pigments If we take chlorophyll molecule in a test tube and provide 2 CO and water and expose the mixture to sunlight, glucose is not formed. If we

Causes of reduced serum hdl levels, Q. Causes of reduced Serum HDL levels? ...

Q. Causes of reduced Serum HDL levels? Possible causes of reduced Serum HDL levels: - Cigarette smoking - Hypertriglyceridemia - Obesity - Genetic factors - Lack

Describe about the primary prevention - food allergy, Describe about the Pr...

Describe about the Primary Prevention - Food Allergy? Let us further, dwell on measures we could adopt in primary, secondary and tertiary prevention. Current research in primar

Fluoride - mineral elements, FLUORIDE It is mostly available in drin...

FLUORIDE It is mostly available in drinking water. Fluoride is essential for the formation of enamel of the teeth. Deficiency of fluoride causes weakness of enamel.

What are the main interspecific ecological interactions, What are the main ...

What are the main interspecific ecological interactions? The major harmonious interspecific ecological interactions are: protocooperation, mutualism and commensalism. The major

How can the abundance and diversity of living beings, How can the abundance...

How can the abundance and diversity of living beings in the tropical forests be explained? The biodiversity of these ecosystems can be defined by the great availability of the

Why in the f1 generation is one of the colors missing, Considering hybridiz...

Considering hybridization in a trait like the color of the flowers of a given plant species (red/yellow) conditioned by a pair of different alleles in relation to complete dominanc

Explain binding of pigments - proteins, Binding of  Pigments, synthetic dy...

Binding of  Pigments, synthetic dye In  addition  to water, lipids and  volatile  flavours,  food proteins  can  bind  a number of other  substances  by  weak interactions  or

Cromngnon skull, Subsequently many such fossils were known from France, Ita...

Subsequently many such fossils were known from France, Italy and middle East. All such fossils exhibited reduced brow ridges, steep forehead, high rounded cranial vault, short face

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