2.3) Metabolic Rate

Question 1

• Describe the 3 factors involved that can measure metabolic rate.

Answer 1

• Oxygen consumption (per unit of time) 🫧
• Carbon dioxide production (per unit of time) 💨
• Heat energy production (per unit of time) 🔥

Question 1

• State the definition of ‘metabolic rate’

Answer 1

• The quantity of energy consumed by an organism per unit of time
  ➞ (allows for comparison within unit of time - e.g. heart rate = bpm)

Question 2

• Describe the 3 apparatuses used to measure metabolic rate.

Answer 2

• Respirometers + oxygen
• Carbon dioxide probes
• Calorometers

Question 3

• What do organisms require to deliver (what) around their cells?

Answer 3

• Organisms with high metabolic rates need efficient ways to deliver oxygen to cells around their bodies.
• Birds and mammals 🦅🐯
  ➞ have higher metabolic rates than reptiles and amphibians 🦎🐸
  ↳ which in turn have higher metabolic rates than fish 🐠

Question 4

• Describe circulation in mammals and birds 🐯🦅

Answer 4

• Mammals and birds
  ➞ have a complete double circulatory system (2 atria and 2 ventricles) ❤️
  ↳ preventing oxygenated and deoxygenated blood from mixing.
• This allows for higher metabolic rates to be maintained
  ➞ as blood leaving the heart is rich in oxygen and can be pumped out at a higher pressure for efficient oxygen delivery in cells
  ↳ which is essential for the high-energy demands of birds and mammals.

Question 5

• Describe circulation in amphibians 🐸

Answer 5

• Amphibians
  ➞ have an incomplete double circulatory system (2 atria and 1 ventricle) ❤️
  ↳ which allows for the mixing of oxygenated and deoxygenated blood to be kept at a minimum (due to timing of contractions between atria)

Question 6

• Describe circulation in reptiles 🦎

Answer 6

• (Most) reptiles
  ➞ have an incomplete double circulatory system (2 atria and 1 ventricle) ❤️
  ↳ which means there is a mixing of oxygenated and deoxygenated blood (because the ventricle is not completely split)
• The only exception is the crocodile (4 chambered heart similar to mammals and birds where the ventricle is completely split) 🐊

Question 7

• Describe circulation in fish 🐠

Answer 7

• Fish
  ➞ have a single circulatory system (1 atrium and 1 ventricle) ❤️
  ↳ which is the simplest vertabrate heart and is a relatively inefficient method of circulation