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Sometimes, on a food chain, each animal is separated with an arrow. If it is pointing right, it meand "is eaten by" or "is consumed by".

Organisms represented in food chains

Primary producers, commonly forming autotrophs, produce complex organic substances (essentially "food") from an energy source and materials. These organisms are typically photosynthetic plants, which use sunlight as their energy source. A few, such as those organisms forming the base of deep-sea vent food webs, are chemotrophic, using chemical energy instead. Organisms that get their energy by organic substances are called heterotrophs. Heterotrophs include herbivores, which obtain their energy by consuming live plants; carnivores, which obtain energy from eating live animals. Ultimately detritivores, scavengers and decomposers may predate living or consume dead biomass.

An animal which eats plants is a herbivore.An animal which eats other animals is a carnivore.An animal which eats plants and other animals is an omnivore.

Flow of food chains

A food chain is the flow of energy from one organism to the next and to the next and so on. Organisms in a food chain are grouped into trophic levels, based on how many links they are removed from the primary producers. Trophic levels may contain either a single species or a group of species that are presumed to share both predators and prey. They usually start with a plant and end with a carnivore. The diagram below is a food chain from a Swedish lake. Osprey feed on northern pike that feed on perch that eat bleak that feed on freshwater shrimp. Though unshown, the primary producers of this food chain are probably autotrophic phytoplankton. Phytoplankton and algae form the base of most freshwater food chains. It is often the case that biomass of each trophic level decreases from the base of the chain to the top. This is because energy is lost to the environment with each transfer. On average, only 10% of the organism's energy is passed on to its predator. The other 90% is used for the organism's life processes or it is lost as heat to the environment. Graphic representations of the biomass or productivity at each tropic level are called trophic pyramids. In this food chain for example, the biomass of osprey is smaller than the biomass of pike, which is smaller than the biomass of perch. Some producers, especially phytoplankton, are so productive and have such a high turnover rate that they can actually support a larger biomass of grazers. This is called an inverted pyramid, and can occur when consumers live longer and grow more slowly than the organisms they consume. In this food chain, the productivity of phytoplankton is much greater than that of the zooplankton consuming them. The biomass of the phytoplankton, however, may actually be less than that of the copepods. Directly linked to this are pyramids of numbers, which show that as the chain is traveled along, the number of consumers at each level drops very significantly, so that a single top consumer (e.g. a Polar Bear) will be supported by literally millions of separate producers (e.g. Phytoplankton).There are many types of food chains or(webs)depending on the certain habitat or environment.