13.1 - Food chains + energy transfer

• In an ecosystem, what do plants synthesise organic compounds from ?

  Atmospheric or aquatic carbon dioxide
• What are saprobionts ?

  Organisms that decompose and breakdown complex materials in dead organisms into simple ones
• What are most of the sugars synthesised by plants used for in the plant ?

  Respiratory substrates
• Apart from respiratory substrates, what else are sugars synthesised by plants used for in the plant ?

  Make other groups of biological molecules
• What do the biological molecules formed from synthesised sugars in plants form ?

  Biomass of the plants
• What are producers ?

  Photosynthetic organisms that manufacture organic substances using light energy
• What are consumers ?

  Organisms that obtain their energy by feeding on other organisms rather than using the energy of sunlight directly
• Define biomass

  Total mass of living material in a specific area at a given time
• 2 ways in which biomass can be measured ?

  Mass of carbon, dry mass of tissue per given area
• What method can be used to estimate the chemical energy store in dry biomass ?

  Calorimetry
• How does bomb calorimetry work ?

  • Warm in oven to evaporate water
  • At intervals weigh the material, when 3 successive are the same there’s no water left
  • Then burn sample in oxygen