Food Chains

• Food chains


  Show what's eaten by what in an ecosystem
• Food chains


  • Always start with a producer
  • Producers make their own food using energy from the Sun
  • Producers are usually green plants or algae
• Photosynthesis


  Producers make glucose
• Biomass


  The mass of living material in a plant, which can be thought of as energy stored
• Energy transfer in an ecosystem

  1. Producers are eaten by primary consumers

  2. Primary consumers are eaten by secondary consumers

  3. Secondary consumers are eaten by tertiary consumers
• Food chain


  • 5000 dandelions... feed... 100 rabbits... which feed... 1 fox
• Consumers


  • Organisms that eat other organisms
  • Primary consumers are the first consumers in a food chain
  • Secondary consumers are second
  • Tertiary consumers are third
• Predators


  Consumers that hunt and kill other animals
• Prey


  What predators eat
• Population of any species

  Usually limited by the amount of food available
• Population of prey increases


  Population of predators increases
• Population of predators increases


  Number of prey decreases
• Predator-prey cycles


  Always out of phase with each other
• It takes a while for one population to respond to changes in the other population