Breathing in Other Animals
Class 7 Science · Chapter 9: Life Processes in Animals · NCERT Curiosity section 9.2.2
Learn
Birds, elephants, lions, cows, lizards and snakes all breathe with lungs, though their lungs differ in structure. Most water animals, like fish, have gills, rich in blood vessels, which take in oxygen dissolved in water and give out carbon dioxide.
Frogs change as they grow: tadpoles breathe with gills; adult frogs use lungs on land and their moist skin in water. Earthworms breathe through their moist skin too, which is why they come up when the soil floods. Each animal's breathing suits its habitat.
Explore: how does each animal breathe?
- Sort each animal.
Remember
- Land animals use lungs; fish use gills to take oxygen dissolved in water.
- Tadpoles use gills; adult frogs use lungs and skin; earthworms use moist skin.
Quick check
An adult frog sitting under water breathes mainly through its …
- moist skin
- gills
- nostrils only
- stomach
Answer
moist skin. On land it uses its lungs.
Think about it
Why does a fish die soon after it is taken out of water?
One answer
Its gills can take oxygen only from water; in air they collapse and dry, so it cannot get oxygen.
Practice
Practise with fresh questions at three levels (easy, medium, hard), some answered hands-on, with hints and worked answers. Get 4 of your last 5 right to finish the topic.