What are Food Chains and Food Webs

What are Food Chains and Food Webs: "Herbivore - an animal that eats plants. (See photos)
Carnivore - an animal that eats other animals. (See photos)
Omnivore - an animal that eats both plants and animals eg bears and humans. (See photos)
Producer - usually a green plant that produces its own food by photosynthesis
Primary Consumer - Animals that consume only plant matter. They are herbivores - eg rabbits, caterpillars, cows, sheep, and deer.
Secondary Consumer - Animals that eat primary consumers (herbivores).
Tertiary Consumer - Animals that eat secondary consumers ie carnivores that feed on other carnivores.
Predators - kill for food. They are either secondary or tertiary consumers - eg polar bears, golden eagles
Prey - are the organisms that predators feed on. Examples of predator and prey species are: fox and rabbit; blue tit and caterpillar; wolf and lamb
Scavenger - a consumer that eats dead animals (e.g. crab, crow, vulture, buzzard and hyena. )
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. . (They do not 'eat' the food like scavengers, as they have no mouth-parts. Instead they break down solid matter into liquids which they can absorb.) Examples: bacteria and some fungi. (See photos)
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."