Respiration
Animal form & functions > Life Processes
How fish can survive in water, where human can't ?
As human lungs do not have enough surface area to absorb enough oxygen from water, and the lining in our lungs is adapted to handle air rather than water. The process of respiration, which releases energy takes place inside the cells of the body and is known as cellular respiration.
When oxygen reacts with food molecules like glucose present in the body cells, energy is released and stored in the form of ATP molecules. The energy stored in ATP is used by the cells as and when required. The process of respiration involves taking in oxygen (of air) into the cells, using it for releasing energy by burning food, and then eliminating the carbon dioxide and water formed in this process.
Amoeba, respiration takes place by the simple diffusion of gases through the cell membrane.
Different animals have different modes of respiration. For example :
- In simple unicellular animals like Amoeba, respiration takes place by the simple diffusion of gases through the cell membrane.
- The animals like earthworms, which live in the soil use their skin to absorb oxygen from air and remove carbon dioxide. So, the respiratory organ in the earthworm is the skin.
- The aquatic animals like fish, prawns and mussels have gills as the respiratory organs, which extract oxygen dissolved in water and take away carbon dioxide from the body.
- In the insects like grasshopper, cockroach, housefly and a mosquito, the tiny holes called spiracles on their body and the air tubes called tracheae are the respiratory organs.
- The respiratory organs of the land animals such as man (humans), birds, lizard, dog and frog, etc., are the lungs (Frogs, however both by lungs and skin).