Meroblastic or partial cleavage, Biology

Assignment Help:

Meroblastic or partial cleavage

The egg does not divide totally because divisions are restricted to only a part of the egg where as the rest of the egg remains completely uncleaved. It is of two types:

A. Discoidal meroblastic cleavage: It occurs in the heavily yoked macrolecithal and highly telolecithal eggs, as for instance in cephalopod molluscs, reptiles, birds and monotremes (egg laying mammals). The cleavage is restricted to the cytoplasmic germinal disc located at the animal pole. Even the germinal disc divides incompletely where as the entire yolk mass remains undivided.

B. Superficial meroblastic cleavage: This takes place in the centrolecithal eggs of insects. Cell divisions are restricted to the peripheral cytoplasmic layer whereas the centrally located yolky is left undivided.


Related Discussions:- Meroblastic or partial cleavage

Nutrition - different feeding habits, Different Feeding Habits Feeding ...

Different Feeding Habits Feeding habits of animals depend on the nature of the food consumed. Herbivorous : When plants are eaten. Examples - Horse, cow, rabbit, apes.

Tissue culture, Tissue culture The ability of a plant cell to give r...

Tissue culture The ability of a plant cell to give rise to a whole plant is called totipotency. The culture of a cell or a tissue in a suitable medium to produce new plan

Neurological symptoms and signs, Neurological symptoms and signs occur in 3...

Neurological symptoms and signs occur in 30 to 40 per cent of patients with IE, are more frequent when IE is caused by S. aureus, and are associated with increased mortality rates.

Disease occurrence due to climate change in animals, Disease occurrence due...

Disease occurrence due to climate change The movement of animal diseases across physical and political boundaries threatens food security and creates a global public co

Nutrient cycles, Nutrient Cycles All ecosystems have certain common ba...

Nutrient Cycles All ecosystems have certain common basic features of structure and function. They all have living and non-living components through which there is a flow of en

Reasons for growth of population, REASON S FOR GROWTH OF POPULATION - ...

REASON S FOR GROWTH OF POPULATION - The human population explosion is mainly a result of reduced death rate. Main reasons for it are - 1 .       Protection from natura

What are the hormones secreted by the adrenal cortex, Q. What are the hormo...

Q. What are the hormones secreted by the adrenal cortex? What are their respective functions? The cortical portion of the adrenals secretes hormones of the corticoid (or cortic

What are the physio-chemical properties of vitreous, What are the physio-ch...

What are the physio-chemical properties of vitreous? PHYSIO-CHEMICAL PROPERTIES OF VITREOUS: Vitreous is a clear gel like optically empty structure. Its physio-chemical prop

Why the depicted food web is not complete, The depicted food web is not com...

The depicted food web is not complete, mainly because:  a. The number of producers is less than the number of consumers. b. There are no decomposers. c. Only secondary co

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