Understandings:

• 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 on 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 influences the structure and rate of change within ecosystems.

Applications and skills:

• Application: Conversion ratio in sustainable food production practices.
• Application: Consideration of one example of how humans interfere with nutrient cycling.
• Skill: Comparison of pyramids of energy from different ecosystems.
• Skill: Analysis of a climograph showing the relationship between temperature, rainfall and the type of ecosystem.
• Skill: Construction of Gersmehl diagrams to show the inter-relationships between nutrient stores and flows between taiga, desert and tropical rainforest.
• Skill: Analysis of data showing primary succession.
• Skill: Investigation into the effect of an environmental disturbance on an ecosystem.