According to legend, a long time ago, because the people wasted food, the Jade Emperor was so angry that he plucked away all the ears of grains. As a result, people's lives have become a problem, and they can only think of finding other food alternatives.

One day, Emperor Shun took his tribe to the nearby Leize Lake for fishing. An old fish spirit swam to the lake and asked Emperor Shun: "Merciful and merciful Emperor Shun, you were wasted food and were punished by God. As a result, our aquarium also suffered. In the past, we could eat some of your leftover soup. Now, What are we eating?"

When Emperor Shun heard this, he said casually: "What are you eating? The big fish eats the small fish!" The big fish had no choice but to swim away. After a while, another group of small fish swam out of the water and asked, "Emperor Shun, you said big fish eat small fish, so we small fish can't starve to death!" Emperor Shun thought for a while and said, "Small fish eat shrimps." As soon as the small fish swam away, a group of shrimps jumped out of the water and asked: "Emperor Shun, who will eat our shrimps?" Shun thought about it for a while and thought that the shrimps really had nothing to eat. Suddenly he saw that the shrimps' legs were covered with mud. , casually said: "You shrimps can eat the sludge!" From then on, the big fish eat the small fish, the small fish eat the shrimps, the shrimps eat the sludge and plankton, forming a food chain.

The food chain is the ecological chain of nature, and it is also the truth for the survival of people on earth. In the process of extensive contact with the biological world, ancient Chinese scholars recorded their insights in their works, indicating that they have further deepened their understanding of the relationship between various animals and plants and the surrounding environment.

There were records and understanding of the food chain in the pre-Qin period. There are complex struggles between different types of animals in order to survive. For example, as early as more than 2,000 years ago, "Zhuangzi" recorded many stories related to the food chain.

Zhuang Zhou, the author of "Zhuangzi", was a native of the Song Dynasty during the Warring States Period. He inherited and developed Laozi's view that "Tao follows nature", denied that ghosts and gods dominate the world, and believed that Tao was the creator of all things. Zhuang Zhou believed that there are a series of complex relationships of mutual benefit among different types of creatures due to the relationship between food.

"Zhuangzi: Mountain Trees" records the famous story of "the mantis stalks the cicada, while the yellow magpie stalks behind".

One day, Zhuang Zhou came to Diaoling Liyuan Garden and saw a strange magpie with broad wings and round eyes flying from the south and stopping in the chestnut forest. Zhuang Zhou rushed up with a slingshot in hand, ready to shoot.

At this time, Zhuang Zhou suddenly saw a cicada, which was sheltered by leaves and forgot itself.

At this moment, a mantis took advantage of the cover of the leaves and stretched out its arms to catch the cicada. The mantis intended to catch the cicada, and when it saw what it had gained, it showed its presence. At this time, the exotic magpie took advantage of the mantis to hunt the cicada, and snatched the mantis. It's just that the strange magpie doesn't know yet that its own life is also in danger.

Zhuang Zhou was frightened when he saw it, and he said vigilantly: "Things that are solid can harm each other, and two kinds of things can harm each other." This means that things can harm each other, and this is because the two kinds of things can harm each other. Caused by mutual attraction and covetousness! Thinking of this, he quickly dropped the slingshot, turned around and ran away.

At this moment, the people guarding the orchard thought Zhuang Zhou was a chestnut thief, so they chased him and scolded him.

This vivid story shows that Zhuang Zhou has discovered the complex relationship between humans hunting birds, birds eating mantises, mantises eating cicadas and other animals. The relationship that Zhuang Zhou saw was actually a food chain that included people.

In the food chain, living things benefit each other. The struggle between different kinds of creatures is inevitable. "Zhuangzi" also has an allusion of "maggots with sweet belts". "Maggot" is a centipede, and "belt" is a big snake. This allusion means that the big snake died after being sucked by the centipede. At that time, there were huge snakes in Lingnan, tens of feet long, and they were specially designed to harm people. Local residents keep centipedes at home until they are more than a foot long, and then place them beside or in pillows.

If a snake enters the home, the centipede will spit and make a sound. Let the centipede come out, and it will bend up, head and tail, and jump about a foot high. It will sit on the big snake's seven-inch position, use the pair of iron hook-like pincers to clamp the snake's head, and suck the snake's essence and blood until it dies. Fang rest.

Things like big snakes that are several feet long, tens of kilograms or hundreds of kilograms in length will die in the hands of centipedes that are only a foot long and as big as a finger, so there is the "maggot" in "Zhuangzi" The origin of "Gandai".

The ancients’ knowledge of using centipedes to make snakes can be traced back to even longer times. In ancient my country, there was a giant centipede that could control snakes. Lu Dian, an official of the Song Dynasty, said in "Piya": The centipede can control snakes. When it suddenly encounters a big snake, it grabs the seven inches of the snake and sucks out the essence and blood.

In ancient times, people not only knew that centipedes can eat snakes, but also that snakes eat frogs, and frogs eat centipedes. The Taoist work of the Southern Song Dynasty "Guanyinzi Sanji" says: "Maggots eat snakes, snakes eat frogs, frogs eat maggots, and they eat each other."

There is a similar story in Lu Dian's "Piya" The description: "The maggots fight the snakes. It is said in the old days that toads eat maggots, maggots eat snakes, and snakes eat toads. The three things are in harmony." Here the frog has been replaced by a toad, but it is still in line with the actual situation of nature.

The concept of animal cannibalism is also reflected in the depictions of bronze arm armors from the Warring States Period unearthed from the ancient Dian culture tombs in Lijiashan, Jiangchuan, Yunnan Province.

There are 17 animals engraved on the bronze arm armor, which can be divided into two groups. The first group of 13 animals includes two big tigers, one of which is biting a wild boar; the other is rushing towards two deer. An ape is climbing a tree to escape. In addition, small animals such as beetles, fish, and shrimps are also engraved.

In the second group of pictures, there are two roosters, one of which is pecking at a lizard, and the moths and beetles next to the lizard are obviously the lizard's food; the other chicken is being eaten by a wild raccoon bite.

In the first set of depictions, the food chain relationship composed of tigers, wild boars and deers is reflected. In the second set of depictions, the relationship between wild raccoons eating chickens, chickens eating lizards, and lizards eating small insects is shown.

The above records show that long before the Song Dynasty, our country had a strong sense of competition among centipedes, snakes, frogs, tigers, wild boars, deer, apes, beetles, fish, shrimp and other animals in nature. Have a deep understanding of the relationship between constraints.

In short, my country has realized in the early stage of biology that in the food chain, an animal is often both a predator and a prey. In other words, a certain organism can feed on many kinds of creatures, and it can itself be eaten by many kinds of creatures, thus forming a complex and intertwined relationship.