Question

Name two classes of vertebrates which possess a three-chambered heart.

Answer 1

Amphibia:

1. They inhabit freshwater and moist land, they live on land but lay eggs in water.
2. Their body is divisible into a head, trunk and tail.
3. Most amphibians have two pairs of limbs. Each limb has five digits and hence, is called pentadactyl limb.
4. The skin is very smooth, moist and sly mean and also contains glands. The skin does not have any external scales.
5. Moist skin is highly vascular and also helps in cutaneous respiration.
6. Respiration can occur through gills, lungs, lining of buccal cavity, and skin.
7. These are cold-blooded animals which means that the temperature of their body fluctuates with the temperature of the outer environment.
8. They have a three-chambered heart with two auricles and one ventricle.
9. Example - Frog (Rana tigrina), Salamander.

Reptilia:

1. These are fully adapted terrestrial vertebrates.
2. Their skin is dry, rough and non-glandular.
3. They possess horny epidermal scales.
4. These are cold-blooded animals with a three-chambered heart having two auricles and one ventricle. The crocodile is an exception which possesses a four-chambered heart that is two auricles and two ventricles.
5. Their body is divided into a head, neck, trunk and tail.
6. They have two pairs of pentadactyl limbs with 5 clawed digits.
7. Respiratory organs are lungs.
8. Example - Flying lizard (Draco), Cobra (Naja)
9. Classes amphibia and reptilia of vertebrates possess a three-chambered heart with two auricles and one ventricle.