Energy and Ecosystems

• consumers are living organisms that feed on other living organisms.
• Producers are autotrophic organisms (plants) that synthesis complex organic molecules from simple inorganic molecules using light energy or chemical energy.
• Saprobionts (fungi & bacteria) are organisms that feed on dead organic matter, releasing molecules, minerals and energy that can then become available to other organisms in that eosystem.
• Biomass is the dry mass of an organism
• Primary porductivity is the rate at which energy is stored in producers.

  Rate of primary productivity can depend on:

  1. sunlight availability
  2. concentration of mineral ions available
  3. ability to use energy to synthesise organic products
  4. amount of photosynthetic pigment in cells
• Why doesnt all solar energy reach producers?

  1. it can be absorbed by rocks
  2. It doesnt reach producers due to positioning (shade)
• Why doesnt all solar energy falling on the leaves convert to organic matter?

  • reflected
  • passes through leaf
  • misses chloroplast
  • wrong wavelength of light
• NPP = GPP - R

  NPP (net primary productivity/ amount of energy into growth)

  GPP (gross primary productivity/ amount of energy fixeby photosynth)

  R (energy lost in respiration)
• N = I - (F + R)

  N = food energy - (poop energy + respiration energy)
• Methods of reducing respiratory losses include:

  1. keep livestock inside & maintain temperature so more energy goes towards growth.
  2. restrict movement & good food supply so less energy goes towards finding food.
  3. treat with antibiotics so less energy is lost to fighting pathogens.
• Eficiency of energy transfer = (energy available before/ energy available after) x 100