9.2 Respiration in Animals

Is Breathing the Same as Respiration?

• Breathing is a physical process — moving air in and out of the lungs.
• Respiration is a chemical process — using oxygen to break down glucose inside cells to release energy.
• Breathing brings oxygen in; respiration uses that oxygen to make energy.
• Both are essential — without breathing there is no oxygen, without respiration there is no energy.

Do All Animals Respire the Same Way?

• All animals respire — but not all breathe the same way.
• Humans and most land animals use lungs .
• Fish use gills to extract oxygen dissolved in water.
• Frogs use both lungs and moist skin at different life stages.
• Earthworms breathe through their moist skin entirely.