The internal structure of earthworms is repetitive. See how you cut the earthworm, you will cut the heart, and those two sections will not live. If only the overlapping parts are cut, then both parts can live. Earthworms themselves are eukaryotes and may not grow into two. Earthworms are one of the higher annelids. Their structures are more complicated than many annelids, and there are digestive system and circulatory system, which is the premise of developing into vertebrates! It also has blood vessels in the back. If you lose too much blood when cutting, it may not become two. There are many external factors that can affect its growth. If it is under the conditions of temperature, pH and sterilization, it is possible to survive! Just like plant tissue culture, of course, cutting off earthworms and tissue culture are not the same principle, but both of them can express lower-level organisms, and the greater their ability to develop into the same independent individuals. Earthworms are low-level animals with a head and a tail, including mouth, stomach, intestine and anus. Their bodies are made up of two tubes with two pointed ends. The outer layer is a circle of body wall, in which there are many muscle systems composed of mesodermal cells. There is a digestive tract in the body, which runs through the layers of membranes from beginning to end. Between the inner tube and the outer tube, it is filled with body cavity fluid, and there is a small hole on the ventral side of each diaphragm, which becomes the passage of body cavity fluid through the body. If the earthworm is cut into two sections, the muscle tissue on the section will contract immediately, and a part of the muscle tissue will dissolve quickly to form a new cell mass. At this time, the white blood cells in the blood gather on the cut surface at the same time, forming a special embolism, which makes the wound close quickly. Its mesodermal cells are very powerful. 3. Study on the regeneration ability of earthworm: If an earthworm is cut into three sections, can the middle section live? Eisenia foetida was cut from a specific part to obtain 18-treated body slices with head and tail, headless and tailless, and cultured in an artificial climate box at 20℃ to observe its regeneration. The results showed that the cut earthworm fragments began to regenerate around 10 d, and they had the regeneration ability from beginning to end. However, the regeneration ability of different segments of earthworm is different, and the regeneration speed of segments with head and tail is faster than that without head and tail. Among them, the head and tail of headless and tailless earthworm can be regenerated, but the regeneration speed of tail is obviously higher than that of head. The number of earthworm nodes left after shearing has a great influence on the survival rate of earthworm. The more remaining segments, the lower the mortality of earthworm segments, and there is a positive correlation between them. (But there is also a saying that not every kind of earthworm has this ability. ) Among them, there is the problem of the regeneration of ciliates and worms. Moreover, it is mentioned that the regenerative ability of coelenterates and planarians decreases from the front end to the back end of the body along the body axis: the mouth or head is the strongest, the mouth or tail is the weakest, and the head nervous system of planarians is concentrated, with the highest metabolic rate. There are many undifferentiated cells in the head of worms and the mouth of coelenterates, which may be the reason for the strong ability of head regeneration. The regeneration ability of earthworm head is also stronger than that of the body segment at the back of the body. If the earthworm is cut into two pieces and the abdominal nerve is removed, the earthworm will lose its regeneration ability. These experiments show that nerves play an important role in regeneration. 5. Further test the regeneration ability of earthworms: Earthworms have strong regeneration ability. After the body is cut off, the embryo-like tissue will be born at the cut-off, and the lost part will be compensated quickly and grow into a new earthworm. The place with strong regeneration ability is to cut off five to eight sections from the front end of earthworm. If the earthworm is cut off from more than nine nodes, its regeneration ability will be slow and the reproductive organs will not be restored. If the fifteenth section of the earthworm is cut off, it will not regenerate its head, but will only grow a tail without a head and become a deformed earthworm with two tails. How long can two tails survive without eating? Or do you eat with a crooked mouth? 6. Someone has done this experiment, cutting off the front and back ends of two earthworms respectively and connecting them can grow into a new earthworm. Some people are even more ingenious. In the first half of an earthworm, the back ends of two earthworms are connected side by side, thus growing an earthworm with two tails.