Secondary egg envelopes, Biology

Assignment Help:

Secondary Egg Envelopes

These are secreted by oviducts and other accessory parts of genital organs while the egg is passing through them from ovary to the exterior.

a) In ovoviviparous sharks the egg is surrounded by a hard shell secreted by shell glands of the oviduct. The shell is drawn out as twisted horns which serve to entangle the egg among sea weeds.

b) In amphibians, the eggs are surrounded by a layer of jelly which protects the egg from adverse effects of sun rays, abrasion as well as from predators (because of its bad taste). The jelly absorbs water and swells.

 c) In birds, reptiles and monotremes, the secondary envelopes include the white of egg surrounding the yolky ovum, followed by inner and outer shell membranes (which are in close contact with one another) and the outermost calcareous shell which is 'porous. The shell is elastic and compressible when the egg is laid but it hardens on exposure to atmosphere.


Related Discussions:- Secondary egg envelopes

Explain about bt reassessment, Will the plant-incorporated protectants rule...

Will the plant-incorporated protectants rules affect the Bt reassessment? No. To make sure that our biotechnology assessments reflect the latest data on health and ecological e

Determine the syndrome of listeriosis, Determine the Syndrome of Listerios...

Determine the Syndrome of Listeriosis Syndrome: Listeriosis in humans is not characterized by a unique set of symptoms since the course of the disease depends upon the state

Illustrate sulfur photosynthetic bacteria, Q. What is the molecule that don...

Q. What is the molecule that donates hydrogen for photosynthesis, in sulfur photosynthetic bacteria? In sulfur photosynthetic bacteria the substance that donates hydrogen is hy

#tit, what three connective tissues are liquid

what three connective tissues are liquid

Objectives of gingival curettage - endodontic surgery, Objectives of Gingiv...

Objectives of Gingival Curettage - Endodontic Surgery a) Provides access and visibility of the apex, b) Removal inflamed tissues, c) Provides biopsy. -  It’s advisable

Cause the inhibition of apoptosis, We now understand that mutations that ca...

We now understand that mutations that cause the inhibition of apoptosis are found in tumors. Because proliferation itself is not induced by the inhibition of apoptosis, explain how

What is the classification of burns, What is the Classification of Burns? ...

What is the Classification of Burns? Burns can be classified on the basis of the extent, depth, patient age and associated illness or injury. On the basis of depth, burns are u

Supra vulvar aortic stenosis, Supra Vulvar Aortic Stenosis :  Supra v...

Supra Vulvar Aortic Stenosis :  Supra valvar aortic stenosis in children with elfin facies, mental retardation, multiple peripheral pulmonary artery stenosis and hyper calcem

Pisces, weberian oscles found in

weberian oscles found in

Volvox Colonial Existence, Necessity of interdependence of Volvox organisms...

Necessity of interdependence of Volvox organisms in the colonial existence

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