Page 261 - New Medley 5 Semester 1

The lungs have thin blood vessels which take oxygen from the inhaled air

and leave carbon dioxide into the lungs which is finally exhaled.

 Aquatic animals like fish breathe through gills. A gill consists of a stack
of thin flaps which have rich supply of blood vessels. The flaps take oxygen

dissolved in water and pass it to the blood. They take carbon dioxide from
blood and release it into the water.

 Amphibians like frogs and toads breathe through lungs when on land and

through their body surface or skin when in water. Therefore, they can live
both on land as well as in water.

 Insects like grasshoppers, bees and cockroaches
breathe through trachea. They have small air holes Knowledge Zone

called spiracles on the sides of their abdomen. All amphibians, lizards and
birds also have lungs for
Each spiracle leads to trachea that reaches every breathing.

part of body, delivering oxygen to the tissues. In
the same manner, the tissues give out carbon dioxide into the trachea, which

is released into the environment through the spiracles.

Oxygen from air → Spiracle → Trachea → Body tissue

↓
To air ← Spiracle ← Trachea ← Carbon dioxide

 Microbes like bacteria, Amoeba and Paramecium are single-celled. They do

not need breathing organs. Oxygen enters through their body surface and
carbon dioxide comes out the same way.

Adaptations for Movement

Animals move from one place to another in search of food, shelter and to protect
themselves from their enemies. This is called locomotion. Different animals have

different types of adaptations for movement.

 Movement in land animals occurs by different means.

l An earthworm crawls by changing its body shape. Its body segments
expand and contract alternately making it move forwards.

l A cockroach walks, runs and climbs with its legs. It also flies with its
two pairs of wings.

l Locusts and grasshoppers hop with strong and long hindlimbs.

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