Food Chains and Energy Transfer

• What is sunlight conserved to by plants?

  Chemical energy.
• What are producers?


  Photosynthetic organisms that manufacture organic substances using light energy, water, carbon dioxide, and mineral ions.
• What are consumers?


  Organisms that obtain their energy by feeding on other organisms.
• What are primary consumers?

  Animals that directly eat producers.
• What are secondary consumers?


  Animals that eat primary consumers.
• What are tertiary consumers?

  Animals that eat secondary consumers.
• What are saprobionts (decomposers)?

  Organisms that break down the complex materials in dead organisms into simple ones, to be absorbed by plants.
• What are most saprobionts?

  Fungi and bacteria.
• What are trophic levels?

  The different stages in a food chain.
• What do the arrows on food chains represent?

  The direction of energy flow.
• What is a food web?

  Many food chains linked together.
• Why are food webs complex?

  All organisms within a habitat will likely be linked to others in the web.
• What is biomass?


  The total mass of living material in a specific area at a given time.
• How is biomass measured?

  By dry mass in a given time and area (grams per squared(area)/cubed(vol) meter).
• How is the chemical energy store in dry mass estimated?

  Using calorimetry.
• What is the method for using calorimetry to estimate the chemical energy store in dry mass?

  A sample of dry material is weighed and then burnt in pure oxygen within a sealed chamber, called a bomb.
• What is the problem with measuring the dry mass of an organism?

  The organism must be killed, so usually only a small sample is measured and this sample may not be representative.