Food Chains

• Organisms that can't make their own food

  Get glucose for respiration by eating other organisms
• Food chains are not very long because energy is lost at all levels, so top predators would not get enough energy to survive
• Biomass


  Producers use some of the glucose they make to produce biomass, some of which is transferred to primary consumers, and then to secondary consumers
• Biodiversity


  The number of species in a habitat, and the amount of genetic variation
• Habitat


  An ecological or environmental area inhabited by a particular species
• Interdependence


  Organisms are dependent on each other, removing one can have a devastating effect on the ecosystem
• Pyramid of numbers


  Shows the feeding relationships in a community, but not the number of living organisms involved
• Pyramid of biomass


  Shows the edible material of organisms which provide energy, different to a pyramid of numbers
• Factors affecting communities


  • Non-living (abiotic) factors: sunlight, water, pH, nutrients, wind, temperature
  • Living (biotic) factors: competition, predation, disease
• Sampling animals


  Sweep nets for small organisms in long grass, pooter to collect small organisms, pitfall traps to passively collect small organisms