Metabolic rate

State the meaning of metabolic rate and how it can be measured

Metabolic rate is the amount of energy an organism will use within a given time.

Metabolic rates can be measured and compared by using:

• Oxygen consumption using respirometers and oxygen probes.

• Carbon dioxide production measured using respirometers and carbon dioxide probes.

• Heat production – Using calorimeters.

Compare birds, mammals, reptiles, amphibians and fish in terms of metabolic rate

Organism with high metabolic rates require a more efficient delivery of oxygen to cells.

Birds and mammals have higher metabolic rates than reptiles and amphibians, which in turn have higher metabolic rates than fish.

Describe the anatomy and physiology of heart chambers and circulatory systems in birds and mammals

Birds and mammals have a complete double circulatory system consisting of two atria and two ventricles.

Also have a four chambered heart

Describe the anatomy and physiology of heart chambers and circulatory systems in amphibians and reptiles

Amphibians and most reptiles have an incomplete double circulatory system consisting of two atria and one ventricle.

Also have a three chambered heart

Describe the anatomy and physiology of heart chambers and circulatory systems in fish

Fish have a single circulatory system consisting of one atrium and one ventricle.
Have a two chambered heart

State the advantage of complete double circulatory systems

Complete double circulatory systems enable higher metabolic rates to be maintained. There is no mixing of oxygenated and deoxygenated blood. Oxygenated blood can be pumped out at a higher pressure. This enables more efficient oxygen delivery to the cell.