Earthworm: structure, nutrition, reproduction, lifestyle

Earthworm Habitat

The earthworm's natural habitat is chernozem soil enriched with organic matter.

The best habitat for these organisms is compost pits, where the processes of decomposition of biological waste with the transformation of nitrogenous compounds occur around the clock. In such conditions, earthworms demonstrate accelerated development rates and lay 2–3 times more eggs than in soil with a poor content of organic components.

Myths

First, some people believe that if a worm is cut in half, two halves will survive. This is not so, only the half on which the head is located will survive and only if a sufficient number of segments remain.

Secondly, the opinion that worms freeze in winter and thaw in spring is incorrect. The frozen worm dies, because of this, at the moment of cold weather, they go deep into the soil and fall into suspended animation. For this reason, invertebrates are found throughout the planet, with the exception of permafrost.

Thirdly, a common myth is that if worms are moved to another soil, they will survive, because their main food is soil. This is also incorrect. In the new soil, the invertebrate may not have enough dead organic matter for food, and a sudden change in conditions and food will cause significant harm to it.

Fourthly, the mucus of a worm is not poisonous and not infectious - it has bactericidal properties. In addition, the invertebrate is not a carrier of infections that can harm humans.

External structure

The following are the characteristics of the external structure of earthworms:

1. Body length from 2 cm to 2 m (depending on the region of residence, climatic conditions, food supply).
2. The number of segment rings is from 80 to 300 units.
3. The presence of shortened bristles with the help of which it moves in the environment. This organ of external structure is located in all segments with the exception of the anterior section.

The bristles of this animal vary in number from 8 to 30 units depending on the size of the individual. The color of the earthworm varies from pale pink to deep burgundy. This feature of the external structure depends on how much the soil in which the worm lives is enriched with nitrogen-based organic substances.

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Internal structure of an earthworm

Representatives of this type of living organisms have a developed internal structure with a muscular, circulatory and respiratory system.

Muscles

The musculature of earthworms is arranged according to the following principle:

1. Under a thin layer of epithelial membrane there is a circular and longitudinal layer of muscle tissue.
2. The synchronized work of different types of muscles changes the shape of individual segments of the worm's body.
3. Alternate spasms of the longitudinal and circular muscles cause the living organism to move by expanding and contracting the joints.

The speed of movement of the animal depends on its age, the number of bristles and individual body segments. Adult sexually mature individuals move 3 times faster than young worms.

Digestive system of an earthworm

In terms of the organization of their digestive function, these animals have a cross-cutting type of nutrition. It looks like this:

1. Food is captured by the oral cavity.
2. It is pushed into the pharyngeal cavity by longitudinal muscles.
3. From the pharynx, food moves into the esophagus.
4. Under the influence of nutrients, the esophagus expands multiple times, transforming into a voluminous goiter.
5. Food is dosed into the stomach, where it is mixed, ground to a pulp using circular and longitudinal muscles, and then the process of partial digestion begins.

Earthworms appear to be primitive organisms, but the organization of their digestive system suggests otherwise.

Excretory organs of the earthworm

The excretory system of earthworms has an even more complex organization than the organs of the digestive tract. This part of the animal body is equipped with special organs - nephridia, which are located in pairs in each segment of the body (except for the first three and the last). The waste products of these individuals enter the environment in the form of liquid.

Waste from processed food is directed by cilia to the nephrostomy. This is the excretory organ of the earthworm, which performs an intermediate function. From the nephrostomy, waste products are directed through the internal septum through a special tube. This part of the animal’s body forms a complex of loop connections that are intertwined by tiny capillaries. From the nephrostomy canals, food waste is expelled by the worm's body through the pores.

Earthworm circulatory system

A detailed description of the structure of the circulatory system of individuals of this species is as follows:

1. Closed-type blood supply system.
2. Blood is a standard red color.
3. The circulatory cycle is represented by 2 main vessels - dorsal and abdominal. Through the first channel, blood is directed from the posterior segment of the body to its anterior part. In the abdominal vessel, blood moves in the opposite direction.
4. The main canals are interconnected by annular vessels, which are also called “hearts”.
5. During contraction of the annular channels, blood is pumped to create intravascular pressure.

The earthworm's body is enveloped in a network of small capillaries that supply epithelial and muscle tissue with nutrients.

Breath

The process of gas exchange is carried out through special cells located in the epidermal membrane of the body. In conditions of high soil moisture, the worm is deprived of the opportunity to carry out full respiration. In this regard, when it rains, animals crawl out to the surface of the earth en masse.

Nervous system of an earthworm

The structure of the nervous system of these individuals is such that it is represented by two nerve nodes in the form of a brain, as well as peripheral branches in the form of an abdominal chain. Due to this organ, the earthworm reacts with lightning speed to touches on the body. Animals of this type have the ability to regenerate lost segments.

Sense organs

The table below describes the sensory organs of earthworms.

Lifespan and reproduction

The reproductive system is represented by female and male genital organs, so earthworms are considered hermaphrodites. Their reproduction occurs quickly by cross-fertilization, i.e. they come into contact with each other for a while and exchange seminal fluid. They can give birth to hundreds of young individuals in a year.

The girdle acts as a genital organ, occupying several segments in the front part of the body. It looks like a thickening from which mucus is secreted. Eggs enter it and a cocoon is formed, the maturation of which lasts 2-3 weeks.

Worms are most active in terms of reproduction in spring and autumn, since in summer the soil is not moist enough and there is very little food.

The lifespan of an earthworm reaches about 10 years, unless they become food for moles or birds, or die due to excessive heat, severe frosts, or the use of pesticides.

How do earthworms reproduce?

Animals of this type are hermaphrodites. Mating of individuals occurs through the cross-connection of the belts, through which the eggs are fertilized. After sexual contact, both worms lay cocoons with young individuals.

Type of earthworm development

Earthworm eggs enter the soil from the belts of maternal organisms 14–30 days after fertilization. After the destruction of the cocoon shell, individuals 1–2 mm in size appear in the ground. After 3–4 months. they grow to the size of adult organisms.

№11

They are quite voracious creatures. They can eat anywhere from ½ of their body weight to their entire body weight each day. For example, if we compared their gluttony with a person, then a person with a body weight of 70 kg could eat from 35 to 70 kg of food per day.

Each earthworm can process about 4.5 kg of organic material per year.

The importance of earthworms in the biosphere, nature and human life

Earthworms have the following significance in nature and human life:

• improve soil quality;
• participate in the processing of organic waste;
• loosen the soil for better ventilation and moisture saturation;
• act as an intermediate host for avian parasites and helminths that infect the lung tissue of pigs.

In the Middle Ages, powdered dried animal worms were used to treat infectious wounds caused by tuberculosis. In Russian folk medicine, a liquid obtained from salted earthworms was used. This substance was dripped into the eyes of people with cataracts.

Interesting Facts

The table below contains answers to the most frequently asked questions.

Earthworms are part of the first tier of the food pyramid of the biosphere. Sexually mature individuals participate in the decomposition of plant waste, loosen the soil, and eat rotting products with a high concentration of nitrogen. The body of these animals is covered with a layer of thick mucus, which consists of enzymes with pronounced antiseptic properties.

The role of vermicompost for soil fertility

American farmers were the first to draw attention to the possibility of using earthworms for processing organic matter. They used them to obtain biomass and expand the diet of domestic animals and birds.

It has been proven that when using vermicompost, the yield of vegetables increases several times. The ripening of the crop is also accelerated by 10-15 days. All thanks to the soil that passes through the esophagus and then contains all the mineral elements and complex compounds necessary for plants. In addition, vermicompost is useful because

• reduces the number of pests in the garden,
• binds heavy metal residues and removes residual radiation,
• increases yield without the use of chemical fertilizers.