Unit 2 - Metabolism and Survival (Metabolic Rate)

Question 1

What is metabolic rate?

Answer 1

Metabolic rate is the amount of energy an organism will use within a given time. At rest, meaning in periods of inactivity, the metabolic rate is known as the basal metabolic rate (BMR). At rest, the BMR is low compared to when the body is undergoing activities like exercise. Organisms with high metabolic rates require a more efficient delivery of oxygen to cells.

Question 2

How can metabolic rate be measured and compared?

Answer 2

• Measure/compare oxygen consumption using respirometers and oxygen probes.
• Measure/compare carbon dioxide production using respirometers and carbon dioxide probes.
• Measure/compare heat production using calorimeters.

Question 3

What are the main blood vessels involved in the circulation of blood around the body?

Answer 3

• Arteries (carry blood away from the heart under high pressure).
• Veins (carry blood back to the heart under low pressure).
• Capillaries (smallest blood vessels which exchange nutrients, gases, and waste products between the blood and body tissue).

Question 4

What happens in the atria?

Answer 4

Where blood enters the heart

Question 5

What happens in the ventricles?

Answer 5

Where blood exits the heart

Question 6

What is the order of metabolic rates (going from highest to lowest)?

Answer 6

1. Birds and mammals
2. Reptiles and amphibians
3. Fish

Question 7

What is the circulatory system of a fish?

Answer 7

Fish have a single circulatory system consisting of one atrium and one ventricle.

Question 8

What is the circulatory system of amphibians and reptiles?

Answer 8

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

Question 9

What is the circulatory system of birds and mammals?

Answer 9

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

Question 10

What are the advantages of complete double circulatory systems?

Answer 10

• 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.