ADAPTATIONS FOR BREATHING

Most animals need a continuous supply of oxygen to survive. The entire process of obtaining and using oxygen is called respiration. That part of the process that involves how an animal takes oxygen from its environment and gives off carbon dioxide is known as breathing. This section focuses on breathing. For a complete description of how oxygen flows to various cells of an animal's body and how it is used by those cells.

The way that animals breathe depends on where they live. Land animals get oxygen from the air. Aquatic animals obtain oxygen from water.

Many land animals have lungs for breathing. As blood flows through the lungs, it picks up oxygen from the air and releases carbon dioxide. The blood then carries oxygen to the rest of the body.

Many aquatic organisms, such as fish and tadpoles, use gills to obtain oxygen that is dissolved in water. Some animals pump water across their gills to increase the efficiency of breathing. Sharks do this by swimming continuously.