Looking back at cellular respiration, we know that we can get much more energy from food aerobic respiration (oxygen) compared to anaerobic (no oxygen). There for in order for complex organisms to survive, they need to be able to exchange oxygen and carbon dioxide. Oxygen and Carbon dioxide are a key requirement in photosynthesis and Cellular respiration.

Earth is host to a wide variety of animals that live in a many different environments. As such different animals have systems in place to extract the max amount of oxygen from their environment.

Before we start talking about the respiratory systems, you should understand a few basic concepts.

• Diffusion
• The basics of Aerobic and anaerobic respiration
• Surface area to volume ratio

We will look at 5 different respiratory systems

Mammals

Amphibians

Fish

Avian

Insects