Food chains and food webs

19.2

What the syllabus asks of you

Describe a food chain as showing the transfer of energy from one organism to the next, beginning with a producer
Construct and interpret simple food chains
Describe a food web as a network of interconnected food chains and interpret food webs
Describe a producer as an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis
Describe a consumer as an organism that gets its energy by feeding on other organisms
State that consumers may be classed as primary, secondary, tertiary and quaternary according to their position in a food chain
Describe a herbivore as an animal that gets its energy by eating plants
Describe a carnivore as an animal that gets its energy by eating other animals
Describe a decomposer as an organism that gets its energy from dead or waste organic material
Use food chains and food webs to describe the impact humans have through overharvesting of food species and through introducing foreign species to a habitat
Draw, describe and interpret pyramids of 15 Draw, describe and interpret pyramids of numbers and pyramids of biomass energy
Discuss the advantages of using a pyramid of 16 Discuss the advantages of using a pyramid biomass rather than a pyramid of numbers to of energy rather than pyramids of numbers or represent a food chain biomass to represent a food chain
Describe a trophic level as the position of an organism in a food chain, food web or ecological pyramid
Identify the following as the trophic levels in food webs, food chains and ecological pyramids: producers, primary consumers, secondary consumers, tertiary consumers and quaternary consumers 17 Explain why the transfer of energy from one trophic level to another is often not efficient 18 Explain, in terms of energy loss, why food chains usually have fewer than five trophic levels 19 Explain why it is more energy efficient for humans to eat crop plants than to eat livestock that have been fed on crop plants