The following sub-topics are covered in this section. 

(a) The organism in the environment 

(b) Feeding relationships 

(c) Cycles within ecosystems 

(d) Human influences on the environment

Students should: 

4.6 understand the names given to different trophic levels, including producers, primary, secondary and tertiary consumers and decomposers 

4.7 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer 

4.8 understand the transfer of substances and energy along a food chain 

4.9 understand why only about 10% of energy is transferred from one trophic level to the next