1) Is earthworm suitable for burrowing life?

Earthworms live in caves in the soil for a long time, so their body shape, structure and living habits will inevitably adapt to the living environment, which is the result of natural selection.

First of all, the head degenerates due to cave life. Although there is a fleshy front leaf at the front end of the body, the front leaf can absorb food when it expands, and can squeeze soil and dig holes when it contracts and becomes sharp. But because it lives underground all the year round and does not rely on vision to find food, only some cells in the front leaf can feel the intensity of light or have vision.

The moving organ of earthworm is bristles, that is to say, it moves by bristles. Using bristles, it can support the body in caves or zigzag forward or backward on the ground.

The earthworm's body consists of many sections, and there is a small hole in the middle of the back between each section, which is called the dorsal hole. This small hole is communicated with the inside of the body, so its body cavity fluid can be discharged from this small hole, and the body can be wetted by this liquid, which increases its lubricity in the soil hole, reduces the friction with coarse sand particles and prevents the body surface from drying. In addition, the wetting of the body surface is closely related to the earthworm's respiration, because it has no special respiratory organs, and the gas exchange between oxygen and carbon dioxide is mainly carried out through the wetted epidermis.

The sensory organs of earthworms are also underdeveloped because of burrowing life. Only the small protrusions on the skin can feel the touch, and the sensory cells of food can also be distinguished in the mouth, as well as the photosensitive cells mainly distributed in the front and back of the body. This photosensitive cell can only be used to distinguish the intensity of light, and has no visual function.

Eat organic matter in the soil.

Select appropriate breeding methods.

There are various ways to raise earthworms, which can be summarized into three kinds, namely, simple feeding method, field feeding method and factory feeding method.

1. Simple culture method. This method includes box culture, pit culture, pond culture, shed culture, hotbed culture and so on. The specific method is to add feed and fertile soil in containers, pits or ponds in layers, and then put earthworm seeds to strengthen feeding management in the process of breeding. This method is suitable for farmers and urban residents. Waste animal feed in protein was produced, organic fertilizer was processed and domestic garbage was treated by using the open space in front of and behind the house, courtyard, old containers, brick ponds and seedbeds. Its advantages are local materials, less investment, simple equipment, simple management method, amateur or auxiliary labor, and full use of organic waste. Earthworms like to wander in the soil.