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

What are some examples of biological activities, Q. What are some examples ...

Q. What are some examples of biological activities in which osmosis plays an significant role? Hemolysis destruction of red blood cells by entrance of water, the hydric regulat

Adverse effects of noise pollution, 1.      Effect on general health:  ...

1.      Effect on general health:          Noise pollution increases the rate of heart beat, constriction of blood vessels and blood pressure. Noise also causes anxiety, stres

Ribosomes in eukaryotic, Q. How dissimilar are the location of ribosomes in...

Q. How dissimilar are the location of ribosomes in eukaryotic and in prokaryotic cells? In eukaryotic cells they can also be found free in cytoplasm and mainly adhered to the e

Determine guidelines for planning balanced diets for elderly, Determine Gui...

Determine Guidelines for Planning Balanced Diets for Elderly? The key element in planning diets for the elderly should be nutrient-based dietary guidelines, in order to reduce

How many weeks are required to recover after blood donation, When a human d...

When a human donor gives a pint of blood, it generally requires how many weeks for body RESERVE of red corpuscles to be replaced? Is it: a) 7 week b) 3 weeks c) 1 weeks

Types of sperm, TYPES OF SPERM Mainly two types . (1) Flagellated Sp...

TYPES OF SPERM Mainly two types . (1) Flagellated Sperm - Generally all sperm are monoflagelated, but in todfish or opsonus sperm is biflagelated. (2) Non flagellated spe

Cell cycle, The cell cycle undergoes a sequence of changes which invol...

The cell cycle undergoes a sequence of changes which involve a period of growth replication of DNA, Followed by cell division. This sequence of changes is called cell cycle.

What is pus, What is pus Pus is a residual of the inflammatory reaction...

What is pus Pus is a residual of the inflammatory reaction. It is having a mixture of fragments of dead leukocytes, infectious agents (generally bacteria) and tissues.

Taxonomy, Write two cytological approaches in taxonomy.

Write two cytological approaches in taxonomy.

How the wet beriberi developed rapidly, How the Wet beriberi Developed Rapi...

How the Wet beriberi Developed Rapidly? Oedema is the significant feature of wet beriberi. It may develop rapidly and involve not only the legs but also the face, trunk and ser

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