Page 246 - New Medley 4 Semester 1

inside. The mother keeps the eggs warm by Embryo

sitting on them. This is called incubation. Air sac Egg shell
The centre of the egg is yellow in colour

and is called the yolk. The yolk contains Albumen
the growing chick or the embryo. The

yolk also contains food for the growing Yolk
chick. The yolk is surrounded by a watery

material, called the albumen. This is the Structure of a bird’s egg
protective layer for the yolk. On the outer side of the albumen, there is a small

air sac, which enables the developing embryo to breathe.

Knowledge Zone
The male penguin takes care of the egg until it hatches, by holding it on top of its feet. A
special flap forms a pocket around the egg to keep it warm and safe from the seagulls.
The father penguin does not eat for weeks while protecting the egg. The mother penguin
remains away, gathers food and returns by the time the egg is ready to hatch. Only then
the father gets a chance to eat and regain strength.

Fishes

A fish lays eggs in water. It lays thousands of

eggs together in a mass called spawn. Fish
eggs do not have hard shells. They are covered

with a soft jelly which protects them. Out of
thousands of eggs, only a few hundreds develop

into young fishes. Most eggs and young fishes
are eaten up by the bigger fishes. Thus, very A fish laying eggs

few young fishes actually grow into adult fishes.

Reptiles

Animals like snakes,

tortoises, lizards and
crocodiles are called

reptiles. They lay eggs Baby snakes coming out of eggs A turtle laying eggs in a pit
on the ground. Their eggs are protected by thick and leathery shells. As a result,

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