Question

Non-cleidoic eggs are found in -
a. Fish
b. Birds
c. Reptiles
d. Mammals

Answer 1

Hint: The outer coverings in non-cleidoic eggs are delicate. It needs to be mature with proper care and safety. They are protected by any shell and laid in water. The nutritive supplement is not proper in non-cleidoic eggs.

Complete answer:
There are many ways to classify eggs like based on the amount, based on the distribution of yolk, etc.
Based on Shell there are two types of the egg
(a) Cleidoic eggs
(b) Non-cleidoic egg

> Cleidoic egg - These eggs contain a solid and hard outermost shell. This hardshell is porous for gases. Yolk, salt, and Water are present in large quantities in cleidoic eggs. Cleidoic egg is a terrestrial adaptation. For example - Birds & Reptiles, Prototherian mammals, and insects.
Non-Cleidoic egg - Egg membranes are squashy in these eggs e.g. All viviparous animals and in oviparous animals that put down eggs in water. For example – fish.

Hence, the correct answer is option (A).

Additional information:
The envelope enclosing the oocyte or ovum is called an egg. Egg envelopes based on the source is of three types.
> Primary egg envelope - These are exuded by egg. e.g: Vitelline membrane - (Zona pellucida & Zona Reticulata)
> Secondary egg envelope - These are emanated by the ovary. e.g: Chorion on insects.
> Tertiary egg envelopes - These are exuded by oviduct. e.g: A jelly cover of frog, Albumin, shell membrane, and shell of Hen.

Note: The eggs which have a solid calcium carbonate covering are known as cleidoic eggs. These types of eggs are found in aves, reptiles, and some mammals. To shield the eggs and prevent it from aridness the shell is required. Pisces, as they lay their eggs in the stream the eggs are non-cleidoic in nature.