- Food Chain - A food chain is the series of organisms showing feeding relationships. A food chain almost always begins with a green plant (producer) which is eaten by an animal (consumer). The arrow means 'is eaten by', and shows the flow of matter and energy along the food chain. There are no decomposers in a food chain.
- Example of a Food Chain
Grass(Producer) 
Grasshopper(1st order Consumer) Kookaburra(2nd order Consumer)
- Producer - usually a green plant that produces its own food by photosynthesis
- First-order Consumer - the organism that eats the producer
- Second-order Consumer - the organism that eats or derives nutrients from the first-order consumer
- Herbivore - a plant eater
- Carnivore - an organism that obtains nutrients from the blood or flesh of an animal
- Omnivore - an organism which eats both plant and animal matter
- Scavenger - an consumer that eats dead animals (e.g. crab)
- Detritivore - a consumer that obtains its nutrients from detritus
- Decomposer - an organism such as bacteria and fungi that breaks down dead organisms and their wastes
- Trophic Level - A trophic level is each level in a food chain. Matter is always 'lost' as heat energy at each trophic level.
- Basal Energy Requirement (B.E.R.) - the amount of energy used by an organism's body just to keep alive, when no food is being digested and no muscular work is being done
- Food Web - a network of interrelated food chains in a given area
