chemical energy

Through a series of

Eat and be eaten

The relationship between the biological and biological closely linked, between these creatures to

Food nutrition

A sequence of relationships linked to each other, called

food chain

. According to the relationship between organisms, the food chain can be divided into

Predatory food chain

、

Crushing food chain

(

Saprophagous food chain

), and

parasitic food chain

The word food chain is Britain.

Zoologist

Elton

(C.S.Eiton) was first put forward in 1927, which, according to himself, was influenced by the China saying ".

big fish eat small fish—law of the jungle

Small fish eat shrimp

Inspired by ". The food chain includes several types: predatory, parasitic, saprophytic, carnivorous, etc. If one

toxic substance

Absorbed by the lower part of the food chain, such as grass, although the concentration is very low, it does not affect the growth of grass, but it is difficult for rabbits to excrete toxic substances after eating grass. When they eat grass frequently, toxic substances will gradually accumulate in their bodies, and eagles will eat a large number of rabbits, and toxic substances will further accumulate in their bodies. So the food chain has

Cumulative sum

Amplification effect.

The United States national bird

Bald Eagle

The reason why it is facing extinction is not that it is killed by people, but that DDT gradually accumulates in its body, resulting in the eggs laid are soft shells and cannot hatch. one

wipe out a species

, it will destroy the balance of the ecosystem and lead to the change of its species number, so the food chain has a very important impact on the environment.