Powerpoint lecture covering the following in a modern, concise format:
Specification Point 4.6 - Understand the names given to different trophic levels, including producers, primary, secondary and tertiary consumers and decomposers.
Specification Point 4.7 - Understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer.
Specification Point 4.8 - Understand the transfer of substances and energy along a food chain.
Specification Point 4.9 - Understand why only about 10% of energy is transferred from one trophic level to the next.
Complete set of Chapter 6 Lectures are available.