A- Ecosystems exist at a range of scales and involve the interaction between biotic and abiotic components.

One example of a small-scale UK ecosystem, to illustrate the concept of inter-relationships within a natural system, an understanding of producers, consumers, decomposers, food chain, food web and nutrient cycle. Thinglink activity on Epping forest

Example of answer: Click on image

B- The balance between components. The impact on the ecosystem of changing one component.
Reintroduction of the grey wolf

C- Overview of the distribution and characteristics of large scale, natural, global ecosystems.
Key biomes: TRF, desert, savannah, tundra, taiga/boreal.

Add: General atmospheric circulation model: pressure belts and surface winds.
Presentation: year-4-introducing-global-ecosystems