1, the food chain is also called "nutrition chain". In order to maintain their own life activities, all kinds of creatures in the ecosystem must feed on other creatures, which is a chain relationship with food as the link. This feeding relationship is actually a relationship in which solar energy is transferred from one organism to another, that is, material energy flows and transforms through the food chain.
2. A food chain generally includes 3-5 links: a plant, a plant-eating animal and one or more carnivores. The number of organisms in different links of the food chain is relatively constant to maintain natural balance.
Extended data:
Classification of food chain:
1, predation: e.g. grass → hare → snake → eagle. Grains → insects → frogs → snakes. Big fish eat small fish, small fish eat shrimp, shrimp eat zooplankton, zooplankton eat green algae.
2, cannibalism: (scavenging food chain). Refers to the food chain formed on the basis of bits and pieces. Such as leaf fragments and microalgae → shrimp (crab) → fish → fish-eating birds.
3. Parasitism: Based on large animals, small animals parasitize on large animals to form a food chain. Such as mammals → fleas → protozoa → bacteria → viruses.
Baidu encyclopedia-food chain