Which is more efficient lungs or gills?

The efficiency of lungs and gills in gas exchange depends on the environment in which they operate. Here is a comparison of their relative efficiencies:

1. Lungs:

- Efficiency in Air: Lungs are highly efficient in extracting oxygen from the air. The large surface area of the alveoli in the lungs maximizes the contact between air and blood vessels, facilitating efficient gas exchange.

- Efficiency in Water: Lungs are not efficient for extracting oxygen from water. Gas exchange in water requires specialized structures called gills.

2. Gills:

- Efficiency in Water: Gills are incredibly efficient in extracting oxygen from water. The thin filaments of the gills provide an extensive surface area, allowing for efficient diffusion of oxygen from water into the bloodstream.

- Efficiency in Air: Gills are not adapted for gas exchange in air. Fish and other aquatic animals that use gills cannot breathe efficiently on land.

In summary, lungs are more efficient for gas exchange in air, while gills are more efficient for gas exchange in water. The specific design and adaptation of each respiratory system match the requirements of the environment in which organisms live.