C2  Communities and Ecosystems

big ninja

Essential Idea:

Changes in community structure

affect and are affected by organisms


  • Most species occupy different trophic levels in multiple food chains
  • A food web shows all the possible food chains in a community
  • The percentage of ingested energy converted to biomass is dependent upon the respiration rate
  • The type of stable ecosystem that will emerge in an area is predictable based on climate
  • In closed ecosystems energy but not matter is exchanged with the surroundings
  • Disturbance influxes the structure and rate of change within ecosystems


  • Conversion ratio in sustainable food production practices
  • Consideration of one example how humans interfere with nutrient cycling


  • Comparison of pyramids of energy from different ecosystems
  • Analysis of a climograph showing the relationship between temperature, rainfall and the type of ecosystem
  • Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest
  • Analysis of data showing primary succession
  • Investigation into the effect of an environmental disturbance on an ecosystem