Question

Compare and contrast the respiratory systems of 2 tetrapods. Describe how their anatomy and physiology differs and relate it to their respective biological roles

Answer 1

Tetrapods are four-limbed animals constituting the superclass Tetrapoda.

Here we are taking Frogs and Lions as the two tetrapods.

Respiratory system of lions

The respiratory organs of lion are the same as that of humans. They have nostrils, mouth, pharynx, larynx, trachea, bronchi. That is they have lung respiration system. By the action of the diaphram, the air enters the lungs. oxygen is absorbed and carbon dioxide is given out. Lions have an upper and lower respiratory tract. the upper respiratory tract is outside the chest (thoracic) cavity, and the lower respiratory tract , which contains gas-exchanging pulmonary tissues, is inside the chest cavity.

Respiratory system of frogs

The frog has three respiratory surfaces on its body that it uses to exchange gas with the surroundings: the skin, in the lungs and on the lining of the mouth. While completely submerged in water, all of the frog's respiration takes place through the skin. The skin is composed of thin membranous tissue that is quite permeable to water and contains a large network of blood vessels. The thin membranous skin allows the respiratory gases to readily down their gradients between the blood vessels and the surroundings. When the frog is out of water, mucus glands in the skin keep the frog moist, which helps absorb dissolved oxygen from the air.

A frog may also breath much like a lion, by taking air in through their nostrils and down into their lungs. The mechanism of taking air into the lungs is however slightly different than in lions. Frogs do not have ribs nor a diaphram, which in lions helps serve in expand the chest and thereby decreasing the pressure in the lungs allowing outside air to flow in. Inorder to draw air into its mouth, the frog lowers the floor of its mouth, which causes the throat to to expand. Then, the nostrils open allowing air to enter the enlarged mouth. the nostrils then close and the air in the mouth is forced into the lungs by contraction of the floor of the mouth. To eliminate the carbon dioxide in the lungs the floor of the mouth moves down, drawing the air out of the lungs and into the mouth. Finally the nostrils are opened and the floor of the mouth moved up pushing air out of the nostrils.

These differences are relating to the habitat in which the frogs and lions live. The lions live in the land only, hence they have lung respiration system only. But the frogs live in land and water since they are amphibians. So they have cutaneous respiration that is respiration through skin as well.