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

Test hypothesis that vertebrates evolved from echinoderms, Q. Evolutionaril...

Q. Evolutionarily protochordates may be intermediate animals between invertebrates and vertebrates. Imagine a scientist is testing the hypothesis that vertebrates evolved from echi

Explain about the reduction tests - carbohydrates, Explain about the Reduct...

Explain about the Reduction Tests - Carbohydrates? These are a group of tests answered by reducing sugars. Since we have already discussed  reducing sugars, you will be able to

Mercury, M e rc u r y The metal is biologically non-essential but ...

M e rc u r y The metal is biologically non-essential but being used in various industries, it is released in environment from both natural and anthropogenic sources. Man-m

What are autotrophic beings, What are autotrophic beings? What are heterotr...

What are autotrophic beings? What are heterotrophic beings? Autotrophic beings are those that can make their own food, i.e., that make organic material from inorganic compounds

Explain gum tragacanth, Gum Tragacanth  Gum tragacanth, the exudation o...

Gum Tragacanth  Gum tragacanth, the exudation of Astragalus species, is defined as the "dried gummy exudate" obtained from Astragalus gummifer Labillardiere. Gum tragacanth is

Syngamy and triple fusion, Syngamy and Triple Fusion After traversing...

Syngamy and Triple Fusion After traversing through the stylar region, the ultimate destination of the pollen tube is to reach the female gametophyte and release the male game

Vacuoles, VACUOLES They are of 4 types - 1.       Sap Vacuole - ...

VACUOLES They are of 4 types - 1.       Sap Vacuole - Outer membrane of sap vacuole is called T onoplast . Sap vacuole contains amino sugars, carotenoids, proteins, m

Agro industrial-glycosides, Glycosides Calcinogenic glycosides: C...

Glycosides Calcinogenic glycosides: Certain plants contain glycosides of the active metabolite of vitamin D. The metabolite is called 1, 25-dihydroxycholecalciferol or mo

What is the modern darwinist theory, In the time of Darwin the results of M...

In the time of Darwin the results of Mendel's research on biological inheritance had not been published, Genetics was not yet developed, neither DNA nor the concept of genetic muta

Explain adverse effects of tenofovir disoproxil fumarate, Adverse effects o...

Adverse effects of Tenofovir disoproxil fumarate  The most common adverse effects have been nausea, vomiting and diarrhea. Renal failure, including a Fanconi-like syndrome, has

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