Energy budget of an animal

• N= I - (F + R)

  • I = chemical energy in ingested food
  • F = faeces
• What is biomass?


  The chemical energy stored within an organism (proteins, fats, glucose, etc)
• Is biomass living or dead?

  Living
• What is biomass measured in terms of?

  The amount of carbon an organism contains
• How is the energy in biomass measured?

  Bomb calorimeter
• What shape are energy pyramids?

  Triangular
• What shape are biomass pyramids?

  Any, they are not always triangular, they may be inverted
• Biomass and energy pyramids

  
• What are the two main ways that farming food chains can be made simpler?

  1. Simplification of the food chain
  2. Decreasing the energy lost through the respiration of livestock
• How are food chains simplified?

  • Decreasing trophic levels
  • Decreasing the amount of pests
• What are the problems with pests?

  • Feed on crops and animals
  • Compete with crop organisms for resources
  • Can directly cause disease in crops
  • Can make infections by pathogens more likely
  • Can spoil food when its being transported
• What are the strengths of chemical pest control?

  • Effective
  • Relatively cheap
  • Does not require a high skill level
• What are the weaknesses of chemical pest control?

  • Chemicals are non-specific
  • Could cause fatality in humans
  • Pests can become resistant
• What are the strengths of biological pest control?

  • Targets one pest only
  • No contamination if licensed
  • Very good in glasshouses
• What are the weaknesses of biological pest control?

  • Takes times to reduce numbers
  • Few successful examples
  • Takes a lot of skill and research
• How can farmers decrease the energy lost through the respiration of livestock?


  • Restrict movement
  • Limit energy used on generating body heat