The common earthworm is essential for improving soil fertility and is also an important part of the diet of many birds and mammals.

& nbsp & nbsp Class - Oligochaetes
& nbsp & nbsp A family - Lumbricides
& nbsp & nbsp Genus / Species - Lumbricus terrestris

& nbsp & nbsp Basic data:
SIZE
Length: usually up to 30 cm, sometimes more.

REPRODUCTION
Puberty: from 6-18 months.
Marriage period: humid, warm summer nights.
Number of eggs: 20 in a cocoon.
Incubation period: 1-5 months.

LIFESTYLE
Habits: loners; on cold or dry days, lie motionless in the ground.
Food: soil that contains organic matter, sometimes small carrion.
Life Expectancy: in captivity up to 6 years.

RELATED SPECIES
About 300 species belong to the family of true earthworms. Their closest relatives are leeches and marine polychaete worms.

& nbsp & nbsp A common earthworm gnaws its way through the ground. Thanks to the activity of earthworms, a fertile soil layer has formed over millions of years. In rainy weather, these animals can be seen on the surface of the earth, but it is not easy to catch the worm, because thanks to the developed muscles, it instantly disappears under the ground.

REPRODUCTION

& nbsp & nbsp Each earthworm has male and female genitals in its body, that is, it is a hermaphrodite. However, in order to reproduce, the worm needs to find another individual with which it exchanges genetic material, since the worm is not able to fertilize itself. Mating of worms occurs at night on the surface of the earth, in wet weather, for example, after rain. Attracted by pheromones, they lie pressed against each other so that the front of one is pressed against the back of the other. Earthworms are covered with a mucous membrane, under which sperm exchange takes place. Having separated from each other, earthworms take away part of the shell, which gradually becomes denser, and then slowly slides off the body to the front end, where fertilization takes place.
& nbsp & nbsp When the shell slides off the body of the worm, it is tightly closed at both ends and a dense cocoon is formed, which can contain up to 20-25 eggs. Very rarely more than one earthworm hatches from a cocoon.

ENEMIES

& nbsp & nbsp At any time of the day, on the lawn or in the meadow, you can see a starling or a black and songbird, which, bowing their heads, listen for a worm somewhere nearby. However, the captured earthworm can defend itself. The bristles on its body and the powerful circular and longitudinal muscles help the rainy worm to abstain in the ground.
& nbsp & nbsp Particularly large and strong earthworms sometimes manage to escape from the bird's beak. Sometimes only a piece of earthworm remains in the bird's beak. If this is the back of the body of the worm, then the animal usually survives, and regains the lost part of the body. Common worms fall prey to hedgehogs, badgers, foxes and even wolves. However, their main enemy is the mole, which also lives underground.

LIFESTYLE

& nbsp & nbsp The earthworm spends most of its life underground. It digs a network of underground corridors that can reach a depth of 2-3 m. The body of an earthworm consists of segments. There are two layers of muscle under the skin. Some stretch along the inside of the body, while others cover the body of the worm in rings. During movement, the muscles pull the body out or squeeze and thicken it.
& nbsp & nbsp The earthworm, straining the annular muscles in the front of the body, moves forward. A wave of muscle contractions then travels through the body to move the back of it. Then comes the turn of the longitudinal muscles, which attract the back of the body. At this time, the front end is pulled forward again. Due to the secreted mucus, the earthworm can move in very hard ground. Sunlight is a serious threat to earthworms, as they are covered with only a thin layer of skin. The worms are not protected from the effects of ultraviolet radiation, so they appear on the surface only in rainy weather. Very often they go outside on rainy nights to collect pieces of straw, paper, feathers, leaves on the ground and pull them into the burrow.

FOOD

& nbsp & nbsp Many species of animals seek food in the earth, but the earthworm eats the earth itself. It feeds on organic matter in the soil. The worm kneads the earth in the muscular stomach, digests some of it, and excretes the rest out in the form of a chair. Some species excrete their excreta on the surface of the earth in small piles visible to the naked eye, while others excrete undigested residues underground.
& nbsp & nbsp Most of all, earthworms love the ground under lawns - about 500 worms can live there in 1 cubic meter of soil. The result of their activity is dry, well-ventilated soil. Such soil is rich in plant residues that are laid out. A large concentration of earthworms in the ground is a guarantee of its productivity. Earthworms live in neutral and alkaline soils. In acidic soil, for example, next to peat bogs, there are few of them. Earthworms also feed on the surface of the earth. In the forest, they collect leaves, pull them into their underground corridors and eat there.
& nbsp & nbsp

DID YOU KNOW THAT ...

• In 1982, an earthworm with a length of 1.5 m was found in England. However, it is much smaller than the Australian and South American species (their length is 3 m).
• Fossil worms, reminiscent of modern earthworms, have been found in geologic layers approximately 600 million years old.
• If an ordinary earthworm loses the end of its body, it will often grow a new one. However, two earthworms will never appear in two parts. A common earthworm that is cut in half dies.
• On the basis of weighing the waste of ordinary earthworms on an area of \u200b\u200b1 m2 during the year, it can be concluded that the earthworm carries 6 kg of excrement to the surface of the earth during this time.

& nbsp & nbsp

HOW DO RAINWORM REPLACE

& nbsp & nbsp Pairing: earthworms are hermaphrodites. They find each other by smell and, connected by a mucous membrane, exchange spermatozoa on the surface of the earth.
& nbsp & nbsp The appearance of the mucous membrane: mucus is secreted from the girdle, a light, thickened part at the front end of the body where numerous glands open. From the mucus secreted, a mucous membrane is formed.
& nbsp & nbsp Fertilization: the mucous membrane moves around the body and collects eggs and sperm.
& nbsp & nbsp Mucous membrane: slides over the head from the body of the worm.
& nbsp & nbsp Cocoon: the slimy container, containing up to 20 eggs, closes and forms a cocoon that is able to withstand even extreme conditions. Most often, only one earthworm hatches from it.

ACCOMMODATION
Earthworms are found all over the world. Common earthworms live throughout Europe and Asia, wherever they find the right soil and climatic conditions.
PRESERVATION
Some gardeners destroy earthworms to get rid of traces of their activity. By doing this, they harm the entire ecosystem.

In the world of fauna is the earthworm. He can rightfully be called an earthen worker, since it is thanks to him that the soil on which we walk is fully saturated with oxygen and other minerals. Passing various plots of land up and down, this worm makes them loose, which allows after that to plant cultivated plants there, as well as engage in gardening.

General characteristics of the species

The earthworm belongs to the Kingdom of Animals, to the sub-kingdom of the Multicellular. Its type is characterized as Ringed, and the class is Small-bristled. The organization of annelids is very high in comparison with other types. They possess a secondary body cavity, which has its own digestive, circulatory and nervous systems. They are separated by a dense layer of mesoderm cells, which serve as a kind of airbags for the animal. Also, thanks to them, each individual segment of the worm's body can autonomously exist and progress in development. The habitats of these terrestrial orderlies are moist soil, salt or fresh waters.

External structure of an earthworm

The body of the worm is round. The length of representatives of this species can be up to 30 centimeters, which can include from 100 to 180 segments. The front part of the body of the worm has a slight thickening, in which the so-called genitals are concentrated. Local cells are activated during the breeding season and perform the function of laying eggs. The lateral outer parts of the body of the worm are equipped with short bristles, completely invisible to the human eye. They allow the animal to move in space and move over the ground. It is also worth noting that the belly of the earthworm is always painted in a lighter tone than its back, which has a maroon, almost brown color.

What is he like from the inside

The structure of the earthworm is distinguished from all other relatives by the presence of real tissues that form its body. The outer part is covered with ectoderm, which is rich in mucous cells that contain iron. This layer is followed by muscles, which are divided into two categories: annular and longitudinal. The former are located closer to the surface of the body and are more mobile. The latter are used as auxiliary ones during movement, and also allow internal organs to work more fully. The muscles of each individual segment of the body of the worm can function autonomously. When moving, the earthworm alternately compresses each ring muscle group, as a result of which its body either stretches or becomes shorter. This allows him to break through new tunnels and fully loosen the ground.

Digestive system

The structure of the worm is extremely simple and understandable. It originates from the mouth opening. Through it, food enters the pharynx and then passes through the esophagus. In this segment, the products are cleaned of acids produced by putrefaction products. The food then passes through the goiter and into the stomach, which contains many small muscles. Here, the food is literally ground and then enters the intestines. The worm has one midgut, which passes into the posterior opening. In its cavity, all nutrients from food are absorbed into the walls, after which the waste leaves the body through the anus. It is important to know that earthworm excrement is saturated with potassium, phosphorus and nitrogen. They perfectly nourish the earth and saturate it with minerals.

Circulatory system

The circulatory system possessed by the earthworm can be divided into three segments: the abdominal vessel, the dorsal vessel, and the annular vessel, which unites the two previous ones. The blood flow in the body is closed, or annular. The annular vessel, which is in the shape of a spiral, unites two arteries vital for the worm in each segment. Capillaries also branch off from it, which come close to the outer surface of the body. The walls of the entire annular vessel and its capillaries pulsate and contract, due to which blood is transported from the abdominal artery to the dorsal artery. It is noteworthy that earthworms, like humans, have red blood. This is due to the presence of hemoglobin, which is regularly distributed throughout the body.

Breathing and nervous system

The respiration process in an earthworm is through the skin. Every cell on the outer surface is very sensitive to moisture, which is absorbed and processed. It is for this reason that worms do not live in dry sandy areas, but live where the soil is always filled with water or in the water bodies themselves. The nervous system of this animal is much more interesting. The main "lump", in which all neurons are concentrated in huge numbers, is located in the anterior segment of the body, but its analogs, smaller in size, are in each of them. Therefore, each segment of the worm's body can exist autonomously.

Reproduction

Immediately, we note that all earthworms are hermaphrodites, and in each organism the testes are located in front of the ovaries. These seals are located in the front of the body, and during the mating period (and they have it cross) the testes of one of the worms pass into the ovaries of the other. During the mating period, the worm secretes mucus, which is necessary for the formation of a cocoon, as well as a protein substance that the embryo will feed on. As a result of these processes, a mucous sleeve is formed, in which the embryos develop. After they leave it with the rear end first and crawl into the ground to continue their race.

The internal structure can be clearly seen when opening the worm.

Before opening, the worm is killed by immersing it in diluted alcohol (10%) for several minutes. Then the worm is placed in the dissecting bath with its back upward (a red blood vessel is clearly visible along its back), with two pairs of pins, it is pinned by the front and rear ends of the body to the bottom of the dissecting tray and then, starting from the posterior end, it is done either with thin scissors or with a blade razor longitudinal section of the skin-muscle sac, keeping slightly to the right of the midline (so as not to damage the translucent blood vessel).

Then the cut walls of the body are deployed on both sides, secured with several pairs of pins and water is poured in so that it covers the opened worm (then its internal structure will be more clearly visible).

On the opened worm, first of all, the body cavity is visible, in which various internal organs lie. Thin transverse septa divide the body cavity into separate chambers corresponding to the external division of the body into segments (Fig. 89).

Of the internal organs, a straight and voluminous intestine is most clearly visible, which runs along the entire length of the body. It consists of several sections: from a small oral cavity, followed by a muscular pharynx, which then passes into a narrow esophagus, leading first to the goiter, then to the gizzard, in which food is rubbed, and, finally, to the long intestine, which stretches to the posterior end of the body and ends in the anal, or anal, opening.

The vessels of the circulatory system are visible above the intestines; they are clearly visible in the earthworm, because its blood is red (remember that we do not find a circulatory system in lower worms and even more so in two-layer animals). A large dorsal vessel runs along the entire intestine.

In the front part of the body, clearly visible paired branches extend from the dorsal vessel, which, like hoops, clasp the esophagus and connect the dorsal vessel with the abdominal one, which runs along the body already under the intestines. These several pairs of vessels are called "hearts" because their muscle walls, by their contractions, force blood to move through the vascular system.

Through the dorsal vessel, blood flows from the posterior end of the body to the front, then through the "hearts" it passes into the abdominal vessel and here it flows in the opposite direction, that is, to the posterior end of the body.

Besides these main vessels, the worm has even thinner vessels; some of them, like "hearts", encircle the intestines, others go to various organs of the body.

The circulatory system brings to the tissues of the body the substances they need - nutrient material that enters the blood from the intestines, and oxygen - and carries away decay products from them - carbon dioxide and nitrogenous substances.

The excretory system of the earthworm has the form of small white convoluted tubes adjacent to those partitions that divide the body cavity into separate segments. One end of each such tube opens in the form of a small funnel into the body cavity, the other end opens outward. Since these excretory tubes (nephridia) are in pairs distributed over separate segments, or segments, of the body, they are also called segmental organs.

The worm does not have a special respiratory system, and gas exchange takes place through the entire surface of the body, dressed with a thin and always moist cuticle. Respiratory gas exchange takes place in moist soil, where atmospheric air also penetrates. In rainy weather, when the soil is saturated with water with a high content of carbon dioxide (released during the decomposition of humus), earthworms feel a lack of oxygen, and this forces them to come to the surface.

The nervous system of the earthworm forms a periopharyngeal ring in the anterior part of the body, consisting of the supraopharyngeal ganglion, or "brain", of a pair of nerve cords covering the pharynx on both sides, and of the subpharyngeal ganglion, located already under the intestine.

The subopharyngeal ganglion begins the abdominal nerve chain, which runs along the lower wall of the body (to see it, the intestines must be removed). The abdominal chain consists of nerve nodes - one for each segment of the body - and nerve cords connecting them. All these nodes are double, that is, each was formed from a pair of nodes merged with each other, and nerves extend from each node to neighboring organs.

Thus, each nerve node is a special nerve center for its segment, but they all act in concert, depending on the activity of the epopharyngeal node, which is therefore called the "brain" of the worm.

Reproductive organs are located closer to the front end of the worm at the bottom of the body cavity. Earthworms are bisexual animals, or hermaphrodites, that is, each of them has both male and female reproductive organs - both testes and ovaries. Both the testes and ovaries open with separate paired openings on the ventral side of the body.

In the structure of the body of the earthworm, one feature clearly stands out: in it, the whole body is subdivided into segments that follow one another, which, in their structure, seem to repeat each other.

Outside, the segments are separated by interceptions and look like rings with eight bristles on each ring, and inside each interception there corresponds a transverse septum and each segment has its own paired nerve node, its own pair of transverse blood vessels encircling the intestines, its own pair of excretory tubes, its own annular and longitudinal muscles. Such a structure, when in the body there are repeated, almost identical parts one after another, is called metameric (Fig. 89, 91).

Who hasn't seen earthworms? Yes, probably everything. However, many do not even know what benefit they have brought us and are, it is very difficult to overestimate it. This voluminous article is about earthworms. The reader can learn for himself about the structure, species, and the way of life of worms under the ground. If you do not know anything about these animals, then after reading the article, your attitude towards them will radically change. At the end of the post, a few videos will be shown for reference. The text will be accompanied by pictures and photos.

- these are quite large invertebrates, up to 3 meters in length. Green worms that live on the territory of Russia belong to the order Haplotaxida (representatives of this order inhabit the entire territory of the Earth, with the exception of Antarctica) and to the Lumbricidae family, which includes about 200 species. About 97 representatives of this family live in Russia. The importance of earthworms for the earth's biosphere is very difficult to overestimate. They eat dead plant tissues and waste products of animals, then they digest it all and mix the resulting mass with the soil. Man has learned to use this feature for his own purposes to obtain the most valuable fertilizer - vermicompost or vermicompost.

These protozoa got their name because when it rains they crawl out of their burrows and are on the surface of the soil. This happens because rainwater fills their holes and they have nothing to breathe, and in order to save themselves they get out.

Vermicompost is a hydrophilic structure that can accumulate moisture. That is, when there is not enough water in the soil, humus releases moisture, and when in excess, it accumulates. The phenomenon of humus release by worms is explained by studying their structure. The fact is that in the intestines of worms, after the decay of organic compounds, molecules of humic acids are formed, and they, in turn, come into contact with various mineral compounds.

Earthworms are very important in the formation of fertile soil, this fact was noticed by Charles Darwin. They dig holes for themselves with a depth of 60-80 centimeters, thereby loosen the soil.

Today worms are widely used by humans for their own purposes. First of all, for obtaining vermicompost. They are actively using worms in poultry and livestock breeding for feeding. Also, worms are very widely used by amateur anglers as good bait.

The structure of earthworms

The structure of earthworms simple enough. The length of individuals that are common on the territory of Russia varies from 2 to 30 centimeters. The whole body is divided into segments, there can be from 80 to 300. The earthworm moves with the help of very small bristles, which are located on each segment of the body, except for the very first. There can be from 8 to 20 bristles on one segment.

Picture: the structure of the earthworm

In the attached picture you can visually observe the structure of the worm. You can determine the front of the worm, where the mouth is, the back, where the anus is. Segments can also be seen.

They are characterized by a closed circulatory system, which is quite well developed. It includes one artery and one vein. The worm breathes thanks to very sensitive skin cells. The skin contains a protective mucus, it contains a large number of antiseptic enzymes. The brain is poorly developed. It consists of only two ganglia. It is very common for worms to exhibit the ability to regenerate. For example, if you cut off his tail, then after a while he will grow back.

Earthworms are hermaphrodites, each with both male and female genitals. Reproduction occurs through the mating of two individuals. The genital organ in worms is a girdle, in size it occupies several anterior segments. The genital girdle stands out well on the body of the worm, it looks like a thickening. In this organ, a cocoon matures from which small worms hatch after 2-3 weeks.

Types of earthworms

The earthworms that live in our country can be divided into two species, which differ in biological characteristics. The first type includes those worms that feed on the surface of the soil (bedding), and the second, those that live and feed in the layers of the soil (burrowing). The first species lives constantly on the soil surface, its representatives do not sink into soil layers that are below 10-20 centimeters.

Representatives of worms, which belong to the second species, unfold their activities exclusively at a depth of 1 or more meters. If necessary, they stick out only the front of the body from the ground.

The second species, in turn, can be divided into burrowing and burrowing worms. Diggers live in deep soil layers, but do not have permanent burrows. Burrowing worms constantly live in the same burrows.

Earthworms of litter and burrowing species live exclusively in moist soils, for example, in places near water bodies. Burrowing worms can live in drier soils.

Worms' lifestyle underground

Worms are nocturnal. At this time of day, you can observe their most active activity. They eat most of the food at night. Many creep out to consume food, but rarely get out of their holes completely - their tails always remain underground. For the day, the worms plug their holes with various objects, such as tree leaves. They can drag small particles of food into their burrows.

For reference. The body of the worms is very stretched, thanks to the numerous segments. In addition, worms have very tenacious bristles. In this regard, forcibly pulling it out of the mink is a rather difficult undertaking.

They are omnivorous. They have a very distinctive diet. First, they swallow a large amount of soil, and then absorb only useful organic substances from it.

Worms are capable of digesting even small amounts of animal feed, such as meat.

Eating food takes place in burrows. First, the worm outside feels for a tidbit and drags it into its pit, where a meal takes place. In order to capture the food object, the worm sticks to it very strongly, then pulls back with all its strength.

Moreover, the worms make themselves a supply of food. They put it in their burrows very carefully. Worms can also deliberately dig another hole just to store food. They plug such a mink with moist earth and open it only if necessary.

It happens in the following order. First, the soil is swallowed, then organic matter is digested inside the worm. After that, the worm crawls out and excrements. Moreover, he puts the waste products in one specific place. Thus, in front of the entrance to the hole, a kind of heap of worm excrement is formed.

Life of worms

Life of earthworms has a very long history. They played a huge role in soil formation. It is thanks to them that we see the earth as it is today.

Worms are constantly engaged in burrowing activity, as a result of which the layer of earth is always in motion. The worms have a very high appetite. In only one day, he can eat the amount of feed that is comparable to him in weight, that is, 3-5 grams.

As a result of their activity, worms contribute to the best growth of plants. Let's not even take into account the fertilizer they produce. Worms loosen the soil and help oxygen and water get into it better. The roots of plants grow much better in the holes of the worms.

As a result of constant loosening of the soil, large objects gradually sink into the depths of the earth. Small foreign particles are gradually rubbed by the stomachs of the worms and turn into sand.

Unfortunately, the number of earthworms in our country is declining. This is facilitated by the non-rational use of chemicals to "fertilize" the soil. To date, 11 species of earthworms have already been included in the Red Book of Russia. Why use chemicals to fertilize the soil when there is such a miracle of nature as biohumus ?!

The role of earthworms in nature very large and hardly overestimated by anything. Worms play a huge role in the decomposition of organic matter. enrich the soil the most valuable fertilizer is humus. They can serve as an indicator: if there are a lot of them in the soil, then the land is fertile.

A complete understanding of the role of earthworms came to humans relatively recently. Up to this point, they mainly resorted to the use of chemical mineral fertilizers, which destroyed the soil and all life in it. Unfortunately, many modern farmers are also in this misconception. Biohumus or vermicompost is a real magic stick for the soil. It contains a very large amount of potassium, phosphorus and nitrogen - substances that are primarily necessary for plant growth.

We got off topic a little. In wildlife, worms keep places where there is a large amount of organic waste. The forest is a good example. When foliage falls out in the fall, it will need to be put somewhere. Soil bacteria and, of course, earthworms will come to the rescue. Immediately after the foliage has fallen, the soil bacteria will take over and decompose it to the compost stage. Then the worms will get down to work and process the compost to the stage of vermicompost and add this most valuable fertilizer to the soil. In principle, this is how soil formation occurs.

The benefits of earthworms

During the Soviet era, chemical mineral fertilizers began to be actively used in the Russian open spaces, which over time destroy entire layers of soil. Today we have just come to the moment when the soil begins to rapidly deteriorate. Chernozem soils no longer give such good results as before. Unscrupulous farmers who think only about their income use fertilizers dangerous for the soil on their plots of land, thereby ruining it. But the restoration of the soil takes a very long period of time, about 1 centimeter in 100 years.

The benefits of earthworms consists in the rapid restoration of the earth from chemical burns and other adverse effects. restore the very structure of the soil due to the introduction and spread of biohumus in it. Even if the land does not need to be restored, adding vermicompost to it will be beneficial in any case. Humus cannot be contaminated with black soil or burned, unlike any other fertilizer. And this is due to the fact that vermicompost has a very similar structure to chernozem. You can even say that humus is a concentrated black soil.

Very great benefits with the help of worms can be brought to your garden, garden or small backyard farm. To do this, you just need to learn how to breed worms yourself, and this is very simple to do. It is enough to dig a hole in the garden and put all organic waste there. Over time, the worms will appear there on their own. Another option is to buy worms. You can also breed worms in separate boxes. As organic waste is consumed, the resulting vermicompost must be collected and scattered around the site.

Worms significantly improve the structure of the soil, improve water exchange and water exchange in it. In a vegetable garden or garden, it is necessary to create all conditions for the development of worms. It would be most rational to build a special box in which all weeds and other organic waste can be put in in summer. Next year, with a large number of worms, you can already get ready-made fertilizer from this box, which can be used in different ways (see photo below). Some advise you to just scatter it around the site, others bury it, and the third one generally prepares liquid top dressing on its basis. In general, there are a lot of applications.

Earthworms - Vermiculture

A fairly large number of farmers and ordinary people who have their own backyard farm are engaged in breeding earthworms in order to obtain vermicompost. And this trend is neither encouraging. Vermiculture may soon replace harmful chemical fertilizers.

Breeding worms can also be considered a good business idea. With minimal costs, you can get the most valuable fertilizer and sell it for good money. It is especially beneficial to do this business, who has a livestock of poultry or farm animals and does not know what to do with their waste products. Household dung is an excellent food for worms, which turns into vermicompost.

In this part of the article, one cannot fail to say about the type of worms that is the most productive - Californian. California worms were bred in 1959 in the United States. These earthworms are most commonly used in this area due to their enormous productivity. There is a California worm as much as an ordinary worm, but its reproduction rate is 100 times higher, and its lifespan is 4 times longer. However, they will have to provide certain conditions of detention.

Before worms are introduced into the substrate, it must be prepared. You need it to turn into compost. It is most convenient to use ordinary metal barrels with a volume of 200 liters.

At home, you can breed worms in various containers. A wooden box with small holes is best suited for these purposes to drain excess water at the bottom, a substrate is laid there and worms are launched. In one summer, a box of organic waste can be turned into vermicompost. See the photo:

Compost is placed here, and non-composted organic waste can be placed on top

You can use boxes of a different design, for example plastic boxes, in which fruits and vegetables are transported:

The disadvantage of the plastic box is too large holes in the bottom, through which the worm can escape from it.

Earthworm videos

“The delicious fruits and vegetables that you see are not a fake. These beautiful fruits are real, and most importantly, environmentally friendly. And all this is due to the fact that they were obtained with the help of an amazing fertilizer - vermicompost. " In this video we will talk about earthworms of the prospector breed. The video is very useful and informative.

This video was shown on television, this is the Galileo program. The reportage was prepared about earthworms.

To enlarge the image, just click on it.

Animals, suborder earthworms. The body of the earthworm consists of ring-shaped segments, the number of segments can reach up to 320. Moving, the earthworms rest on short bristles, which are located on the segments of the body. When studying the structure of the earthworm, it can be seen that, in contrast to the whipworm, its body looks like a long tube. Earthworms are distributed throughout the planet, except for Antarctica.

Appearance

Adult earthworms are 15-30 cm long. In the south of Ukraine, it can reach large sizes. The body of the worm is smooth, slippery, has a cylindrical shape and consists of piece-piece rings - segments. This shape of the worm's body is explained by the way of his life, it facilitates movement in the soil. The number of segments can reach 200. The ventral side of the body is flat, the dorsal side is convex and darker than the ventral side. About where the front of the body ends, the worm has a thickening called a girdle. It contains special glands that secrete a sticky liquid. During reproduction, an egg cocoon is formed from it, inside which the eggs of the worm develop.

Lifestyle

If you go out into the garden after the rain, you can usually see small heaps of earth thrown out by earthworms on the path. Often the worms themselves crawl along the path. Precisely because they appear on the surface of the earth after rain, they are called rain. These worms also crawl to the surface of the earth at night. Usually, the earthworm lives in humus-rich soil and is not common on sandy soils. He also does not live in swamps. Such features of its distribution are explained by the way of breathing. The earthworm breathes over the entire surface of the body, which is covered with mucous, moist skin. Too little air is dissolved in the water, and therefore the earthworm suffocates there. He dies even faster in dry soil: his skin dries up, and breathing stops. In warm and humid weather, earthworms keep closer to the surface of the earth. During a prolonged drought, as well as in a cold period, they crawl deep into the ground.

Moving

The earthworm moves by crawling. At the same time, he first draws in the front end of the body and clings to the bristles located on the ventral side for the unevenness of the soil, and then, by contracting the muscles, pulls the rear end of the body. Moving underground, the worm makes holes in the soil. At the same time, he pushes the ground with the pointed end of the body and squeezes between its particles.

Moving in dense soil, the worm swallows the earth and passes it through the intestines. The worm usually swallows the earth at a considerable depth, and throws it out through the anus at its burrow. So on the surface of the earth, long "laces" of the earth and lumps are formed, which can be seen in summer on garden paths.

This method of movement is possible only with well-developed muscles. Compared to hydra, the earthworm has more complex muscles. It lies under his skin. Muscles together with the skin form a continuous musculocutaneous sac.

The muscles of the earthworm are arranged in two layers. Under the skin is a layer of annular muscles, and under them is a thicker layer of longitudinal muscles. Muscles are made up of long, contractile fibers. With the contraction of the longitudinal muscles, the body of the worm becomes shorter and thicker. Contraction of the annular muscles, on the contrary, makes the body thinner and longer. Contractions alternately, both layers of muscles determine the movement of the worm. Muscle contraction occurs under the influence of the nervous system, which branches into muscle tissue. The movement of the worm is greatly facilitated by the fact that there are small bristles on its body on the ventral side. They can be felt by running a finger soaked in water along the sides and along the abdominal side of the worm's body, from the back to the front. With the help of these bristles, the earthworm moves underground. By them, he is delayed when he is pulled out of the ground. With the help of bristles, the worm descends and rises along its earthen passages.

Nutrition

Earthworms feed mainly on half-decayed plant remains. They drag, usually at night, leaves, stalks and so on into their burrows. Earthworms also feed on humus-rich soil, passing it through the intestines.

Circulatory system

The earthworm has a circulatory system that the hydra does not have. This system consists of two longitudinal vessels - the dorsal and the abdominal - and branches that connect these vessels and carry blood. The muscle walls of the vessels, by contracting, drive blood throughout the body of the worm.

The blood of an earthworm is red, it is very important for the worm, as well as for other animals. With the help of blood, the connection between the organs of the animal is established, and metabolism occurs. Moving through the body, it carries nutrients from the digestive system, as well as oxygen entering through the skin. At the same time, the blood carries carbon dioxide from the tissues into the skin. Various unnecessary and harmful substances formed in all parts of the body, along with the blood enter the excretory organs.

Irritation

The earthworm has no special sense organs. He perceives external stimuli with the help of the nervous system. The earthworm has the most developed sense of touch. Sensitive tactile nerve cells are located throughout the surface of his body. The sensitivity of the earthworm to various kinds of external stimuli is quite high. The lightest vibrations of the soil make it quickly hide, crawling into a burrow or into deeper layers of the soil.

Sensory skin cells are not limited to touch. It is known that earthworms, without special organs of vision, still perceive light stimuli. If you suddenly light up a worm with a lantern at night, it quickly hides.

The response of an animal to stimulation, carried out by the nervous system, is called a reflex. There are different kinds of reflexes. The reduction of the body of the worm from touch, its movement under sudden illumination by a lantern has a protective value. This is a protective reflex. Grasping food is a digestive reflex.

Experiments also show that earthworms sense odors. The sense of smell helps the worm find food. Even Charles Darwin established that earthworms are well distinguished by the smell of the leaves of the plants they feed on.

Reproduction

Unlike the hydra, the earthworm reproduces exclusively sexually. He does not have asexual reproduction. Each earthworm has male organs - testes, in which live gums develop, and female genital organs - ovaries, in which eggs are formed. The worm lays its eggs in a slimy cocoon. It is formed from a substance secreted by the girdle of the worm. In the form of a muff, the cocoon slides off the worm and contracts at the ends. In this form, the cocoon remains in the earthen burrow until the young worms emerge from it. The cocoon protects eggs from dampness and other adverse influences. Each egg in the cocoon divides many times, as a result of which the tissues and organs of the animal are gradually formed, and, finally, small worms, similar to adults, emerge from the cocoons.

Regeneration

Like hydras, earthworms are capable of regeneration, in which lost body parts are restored.