Why do earthworms survive when cut in half?

Because the earthworm has a total of 7 hearts in its body, although you cut it into 2 segments, its heart is not damaged, and the earthworm's self-recovery ability is quite strong, and the earthworm that is cut into 2 segments will each grow into a new earthworm.

The earthworm is very special, just as its body is divided into segments without obvious merger, and its heart is also divided into several segments with the front part of the body, generally 4 5, in the form of a ring, like a bulging blood vessel, so there are also called ring blood vessels.

The excretory organ of earthworms is the posterior renal duct, and the general species have a pair of typical posterior renal ducts per somite, called the large renal duct.

The circulatory system is also present in every body segment. However, I think the heart should be the root cause.

The earthworm is cut into two pieces and still alive.

After the earthworm is cut in two, the muscle tissue on the section will contract strongly, and some muscle tissue will quickly dissolve, and then form a new cell mass. At this time, the white blood cells contained in the blood are also concentrated on the cut surface at the same time, forming a special embolism, which allows the wound to close quickly.

Moreover, its mesoderm cells also have a very strong ability to differentiate, when it has a wound, the original cells that are originally located in the diaphragm in the body cavity have not yet differentiated, quickly move to the wound section, and connect with their own dissolved muscle cells, forming a nodular-like bulge on the section surface, which is called regeneration bud.

Morphological structure of earthworms:

The body is segmented but not divided, the verrucous feet are vestigial, and the body surface is bristled. Hermaphroditic, 1-2 pairs of gonads, reproductive ducts of body cavity origin, rings (clitellum) appear on the body surface when sexually mature, mutual insemination can be done during mating, eggs are laid in the rings, and after falling off, egg cocoons are formed, and they develop directly.

The bristles are simple, 8, sometimes many, arranged in a ring, 1-2 pairs of sperm nests, usually at 10-11 nodes, male reproductive pores one pair, located on 2 or more somites after the posterior sperm nest, i.e. after 14 nodes. A pair of ovaries, located in the 13th segment, with a thicker annular band and less yolk.

The chromosome 2n=22 chromosome of the earthworm has been used to identify the chromosomal karyotype analysis method in China, which is exactly the same as the artificially bred earthworms "Taiping No. 2" and "Beixing No. 2".

<> earthworm is cut into two and can still survive when it touches the ear segment. When the earthworm is cut off, the muscle tissue on the section immediately contracts, and a part of the muscle quickly dissolves to form a new cell mass, and at the same time, the white blood cells gather on the cut surface to form an embolism, and the noisy clump makes the wound quickly closed. At this point, the protist cells dissolve with the section, forming nodular sprouts on the section.