Question

Aquatic animals breathe at a slower rate than the terrestrial animals.
A. True
B. false

Answer 1

Hint: Breathing is the phenomenon of moving air inside and outside of the respiratory organs of the organism. It is the process through which gaseous exchange with the internal environment which allows the removal of carbon dioxide and transportation of oxygen. In living organisms, the exchange of gases such as oxygen and carbon dioxide is essential for proper functioning of the body.

Complete answer:
The organs of respiration in the aquatic organism are the gills. The gills are covered with numerous blood vessels which work to absorb the oxygen dissolved in the water. When an aquatic organism breathes through its gill, the water moves past the gills which are filled with blood vessels. As the water moves over the gills, the oxygen that is dissolved into the water enters the blood circulation of the organism and then moves towards the cell.

The problems of aquatic breathing in the aquatic organism is solved through a rate of breathing which is much higher than the land animals. The fishes have efficiently developed gills that allow exchange of oxygen in water through a system of counter current mechanisms.

Additional information:
Water is made up of hydrogen and oxygen molecules and is heavier than air. This creates a problem on the flow of water to move over the gills of the fishes. The oxygen content of water is also very low than air. Water contains about twenty times less oxygen than air. Since, water is harder to reach and moves around and contains less oxygen as compared to air, the fishes need to breathe quickly in order to draw more oxygen.

The diffusion of oxygen in air is much faster than its diffusion in water and the process of replenishing oxygen in water is also very slow. Due to the slow diffusion of water, the aquatic organism must provide greater surface area for diffusion of oxygen from the water. This is counteracted by the aquatic organism by speeding the rate of respiration and circulating the surface area with the exchange medium, water at a much faster rate.

Hence, the correct answer is option (B).

Note: In aquatic organisms, the gills are the organ of breathing or absorbing oxygen from the surroundings. The aquatic organism living in water breathes oxygen dissolved in water and absorbs the oxygen through the process of diffusion. Water contains much less oxygen than the air. It is allowed to move over the surface area of the gills and oxygen is absorbed through diffusion. However, to avoid the oxygen stress and other problems related to aquatic respiration, the aquatic animals breath at a faster rate than the land animals.