Energy Transfers and Cycles

• What is an ecosystem ?

  All the organisms living in a particular area and all the non living (abiotic) conditions.
• What are producers ?

  organisms that make their own food
• What is biomass ?

  The chemical energy stored within an organism or the mass of the living material of the organism
• What are moicrobrial consumers which aid the decay of dead organisms called ?

  saprobionts
• What is the difference between a food chain and a food web ?

  A food web shows the simple lines of energy transfer but food webs show lots of food chains in an ecosystem and how they overlap.
• Describe how you would produce a sample of dry mass.

  Dry the sample by putting it in the oven at a low temperature. Weigh the sample at at regular intervals . Once the mass becomes constant you know all the water has been evaporated.
• How can you estimate the amount of chemical energy stored in biomass ?

  A sample of dry biomass is burnt and the energy released is used to heat a known volume of water. The change in temperature of water is used to calculate the chemical energy.