The musculoskeletal system of the earthworm. Features of the structure of the earthworm, its significance in nature
Earthworms, they are earthworms, this is far from being one species, but a whole suborder of the class Oligochaete worms, which belongs to the phylum Annelids. The earthworm is characterized by most of the structural features of its type and class.
Earthworms are ubiquitous. Our area is home to more than a dozen similar species (European earthworms), whose body length is 10-20 cm, the number of segments is 100-180. At the same time, the Australian earthworm can reach a length of 3 meters.
During the day, earthworms crawl in the soil. At night and after rain they can come to the surface. With the onset of cold weather, they go underground, to a depth of 2 m. The back of the body is slightly flattened. When crawling out of the soil, the worm holds the edge of the hole with its rear end.
The body of an earthworm, as a representative of annelids, is divided into segments by ring constrictions. As in all oligochaetes, the parapodia are reduced, only tufts of bristles are preserved from them, which allow the worm to cling, rest against the ground and facilitate pushing the body forward. In other words, the bristles provide adhesion to the substrate.
The surface of the body is moist and covered with mucus, which facilitates movement in the soil and also facilitates the penetration of oxygen into the body.
The epithelium secretes a layer of transparent cuticle and also contains many mucous cells. Under the epithelium there are circular and longitudinal muscles. The body of an earthworm can contract and elongate. Circular muscles make the body of the worm thin and long, longitudinal muscles shorten and thicken. The longitudinal layer of muscles is more powerful. Alternate contraction of these muscles ensures movement. Each segment can change its shape separately.
The coelomic sacs of adjacent segments communicate with each other, thus the liquid in them mixes.
An earthworm often swallows soil, eating its way through. Nutrient particles are absorbed from the soil in the intestines. If the soil is soft, then it drills it with the front end. First, the front end is stretched and thinned, inserted between lumps of soil. Then the front end thickens, causing the soil to move apart. Next, the worm pulls up the back of the body.
They feed on rotting plant debris. In addition, they can drag fallen leaves from the surface. By dragging plant debris into the soil, worms contribute to their decomposition and the formation of fertile soil.
The digestive system consists of the mouth, pharynx, esophagus, crop, gizzard, midgut, hindgut, and anus. Swallowing food is done through the muscular pharynx. The stomach grinds food; in addition to the muscles of the walls, swallowed grains of sand are involved in this. On the dorsal side, the wall of the midgut forms an invagination, increasing the absorption surface. The midgut is lined with ciliated epithelium, in which there are many unicellular glands. Complex organic substances are broken down in it, and simpler substances are absorbed into the blood. In the walls of the earthworm's midgut there is a dense network of blood vessels. The hindgut is small and ends at the anus.
A special feature of earthworms are calcareous glands, whose ducts flow into the esophagus. The substances they release neutralize the acids contained in the soil.
Breathing occurs over the entire surface of the skin. In the superficial layers of the body wall there is a dense network of blood vessels. When it rains, earthworms crawl to the surface due to lack of air in the soil.
The circulatory, nervous and excretory systems are similar to polychaetes. However, in the circulatory system there are so-called “hearts” - annular vessels capable of muscular contraction. Located in segments 7-13. In a number of species, ring vessels are present only in the anterior part of the body.
There are no metanephridia (excretory organs of annelids) in the anterior three segments.
Sense organs are poorly developed. The skin contains sensitive cells - organs of touch. There are also cells in the skin that perceive the degree of illumination.
Earthworms are hermaphrodites. The reproductive system is located in several segments of the anterior part of the body. The testes are located in front of the ovaries.
Mutual cross fertilization. Each of the mating worms transfers sperm to the partner's seminal receptacle.
In the first third of the body of earthworms there is a special belt; its glandular cells secrete mucus, which, when dried, forms a muff. Unfertilized eggs are laid in it. After mating, spermatozoa enter from the seminal receptacles. Fertilization occurs. After this, the sleeve slides off the worm's body and turns into a cocoon. Small worms develop from the eggs.
Capable of regeneration. If a predator tears off part of the worm's body, the other half completes the missing part. If the worm is divided into two parts, the result is two individuals, which can be considered asexual reproduction. However, the earthworm itself does not reproduce this way.
The earthworm has been known to everyone, probably since childhood. Everyone remembers the pink creatures that appear out of nowhere after the rain. But not everyone knows that earthworms are a real treasure for the earth; they play a big role in the ecosystem, enrich the earth with nutrients, and provide food for many birds and animals. There are many interesting facts that reveal all the secrets of the “extraordinary” inhabitant of the earth’s bowels, who does not look attractive at all, but is of great importance in nature and human life.
Structure and description of worms
Earthworms are a type of annelid. They live mainly in moist soil rich in humus. Interestingly, the habitat is 5 continents - all except Australia. The features of their appearance are as follows::
Each segment also has bristles that help it move underground. The tube-shaped body completely lacks bones and cartilage; the body cavities are filled with liquid. The earthworm is perhaps the most amazing creature that lives in the soil; it has no eyes, no lungs, no ears. Breathing occurs through the skin. The worm has several hearts, and the digestive system runs along the entire length of the body.
The mucous glands located between the segments secrete mucus, which protects against drying out, helps in movement underground, and prevents soil from sticking to the body. And it scares away predators because it tastes very bad.
The average life expectancy is from 4 to 8 years. However, there are cases when the age of the worm reached even 10 years. It is difficult to find such long-livers in nature, since any bird or rodent and, of course, humans pose a danger to them. The greatest threat currently comes from chemical fertilizers generously added to the soil, most of which are lethal to worms.
Favorite food
A very interesting question is what earthworms eat. Their “menu” is quite modest; the basis of the diet is fallen, rotting leaves, as well as other organic remains - roots, rotten wood. Worms have teeth in their stomach. Liquid-like soft food is absorbed through the pharynx, then muscularly pushed further - into the goiter, and then into the stomach, where it is crushed and ground with the help of the so-called teeth - hard growths similar to the incisors we are used to. When the gastric muscles contract, these hard tooth-like processes come into motion. Digestion occurs in the intestines.
Undigested food remains are deposited in the soil. In one day, an adult earthworm can process half a kilo of soil!
Lifestyle
As you know, earthworms are underground inhabitants. They spend most of their lives digging underground passages and holes; the network of such corridors can reach a depth of 2-3 meters. Worms are nocturnal animals by way of life. Their body is not at all protected from ultraviolet radiation, so the peak of activity comes in the evening and at night. As a “home” they prefer moist soil rich in humus. Animals do not like either sandy or overly swampy areas. This is due to breathing patterns.
They take in oxygen through their skin, but in excessively damp soil there is very little air, which causes inconvenience and the animal begins to suffocate. This explains their behavior after the rain. The ground becomes so wet that the worms are forced to crawl to the surface to avoid suffocation.
In dry soil, the mucus covering the skin dries out, depriving the worms of the ability to both breathe and move comfortably. With the arrival of cold weather, earthworms go into the deeper layers of the soil.
Reproduction of worms
The small soil dweller has the specificity of reproducing offspring. Reproduction of earthworms occurs mainly in the warm season and stops during drought and cold snap, when they go into the deeper layers of the soil to winter.
Everyone knows that earthworms are hermaphrodites. The body of the worm contains both male and female genital organs. However, this is not enough for reproduction. Invertebrates need another individual with whom the mating process will occur - the exchange of genetic material. Worms find a partner by smell, since their bodies produce pheromones that are sensed by another earthworm. Reproduction occurs as follows.
They mate on the surface of the ground in wet weather. In the process, the worms are pressed against each other so that the back end of one worm is pressed against the front end of the other, in other words, a jack. The mucous membrane ensures the exchange of sperm. After separation from each other, each worm remains with a part of the sperm-rich shell, which gradually hardens and becomes denser and passes to the anterior end of the worm, where fertilization occurs. Then the shell slides off the body and closes, forming a kind of cocoon, very dense in structure.
It safely stores about 20-25 eggs. This cocoon is able to protect eggs even in conditions of drought or extreme cold. However, as a rule, only one worm hatches from one cocoon; the rest die.
Role in nature
Some gardeners mistakenly consider earthworms to be harmful “insects” that eat young shoots and gnaw on plant roots. This opinion is absolutely wrong. On the contrary, they play a vital role in creating fertile soil. Worms are a kind of factory, a humus production system. Worms also dig passages and holes, enriching the soil with oxygen and moisture. They improve fertility, mineral composition and soil structure. This process is gradual and occurs in stages.:
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This is the role of invertebrates in soil formation.
In nature, everything is interconnected, so worms are little helpers not only in agriculture, but also have their own function in the entire ecosystem. They are the orderlies-cleaners of the earth, help in the decomposition of organic remains. And finally, the presence of worms is a good indicator of soil fertility.
Increase in quantity
Undoubtedly, the earthworm is a good friend of the gardener and gardener. Therefore, it is worth not being lazy and creating favorable conditions for them to live and reproduce, for which beneficial invertebrates will repay a hundredfold. The main factor in their life is moisture (which is why, when you lift an old stump or garden bricks from the ground, you can see wriggling pink tails underneath them). They do not live in dry soil, but go to the depths.
The best way to keep the soil moist is to mulch. This is covering the beds with a small layer of straw, leaves or humus. And also don’t be too zealous with chemical fertilizers.
Self-breeding
You can breed worms at home to use them for fishing, to feed pets - hedgehogs, bats, birds, and also to produce vermicompost - a universal and environmentally friendly fertilizer. Vermicompost is a unique product made from recycled earthworm waste.
Breeding worms is accessible to everyone, simply and without investment. What for this it is necessary:
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These simple rules will allow you to make a home vermifarm. These representatives of the “belt worms” class are unpretentious in care and nutrition, so diluting the required amount of them will not be difficult at all. An unusual farm will help show children what life cycle their familiar invertebrates go through.
The story of Charles Darwin and the earthworm is very instructive. The great scientist has been known to everyone since his school days as the founder of the theory of evolution. But few people know that this researcher was very interested in studying common worms. He devoted a lot of time to studying them, even writing scholarly works on this topic. As an experiment, Darwin placed several individuals in pots of soil and observed them. During the experiments it turned out that the worms are able to eat even meat. The scientist attached small pieces of meat to the surface of the pots and checked after a few days - the product was almost completely eaten.
They could also eat pieces of their dead brethren, for which the biologist even called the worms the bloodthirsty nickname “cannibals.”
Decaying leaves are used by worms not only for food. They can drag and plug the entrances to their burrows with leaves, old grass, and scraps of wool. Sometimes you can find a hole filled with bunches of leaves and grass. Darwin assumed that this was insulation before the cold season.
According to the scientist, it is worms that help in the preservation of historical values and treasures. Over the course of several years, stone tools and gold jewelry are gradually covered with worm excrement, which reliably preserves them from the influence of time.
Currently, 11 species of earthworms are listed in the Red Book.
Invertebrates are 82 percent pure protein, making them a nutritious food for some peoples around the world. Often travelers or soldiers in difficult situations who find themselves in the jungle survive by eating worms. Plus, this diet is good for your health! Scientists have found that eating worms lowers cholesterol levels.
The largest earthworm was discovered in South Africa, its length was 670 cm. This is a real giant!
Many people believe that if a worm is cut or torn in half, both parts will survive. But that's not true. Only the front part, the head, survives, since the worm feeds using the front part, and to live it needs to eat, like all living creatures. The front part will grow a new tail, the back part, unfortunately, is doomed to death.
The earthworm is a special inhabitant of our planet. It brings her great benefit. Therefore, we should not forget about its significance in the natural system. Surprisingly, Charles Darwin considered earthworms to be somewhat similar to humans and suspected that they contained the rudiments of intelligence.
Who hasn't seen earthworms? Yes, probably everything. However, many do not even realize what benefits they have brought and are bringing to us; it is very difficult to overestimate. This lengthy article is dedicated to earthworms. The reader can learn for himself about the structure, types, and lifestyle of worms underground. If you know nothing about these animals, then after reading the article your attitude towards them will radically change. At the end of the publication, several videos will be shown for your reference. The text will be accompanied by pictures and photos.
- These are quite large invertebrates, measuring up to 3 meters in length. Green worms that live in Russia belong to the order Haplotaxida (representatives of this order live throughout the Earth, with the exception of Antarctica) and to the family Lumbricidae, 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 tissue and animal waste products, then digest it all and mix the resulting mass with the soil. People have learned to use this feature for their own purposes to obtain the most valuable fertilizer - vermicompost or vermicompost.
These protozoa get their name because when it rains, they crawl out of their holes and stay on the surface of the soil. This happens because rainwater fills their holes and they can’t breathe, so they crawl out to save themselves.
Biohumus is a hydrophilic structure that has the ability to accumulate moisture. That is, when there is not enough water in the soil, humus releases moisture, and when there is excess, it accumulates. The phenomenon of humus secretion by worms can be explained by studying their structure. The fact is that in the intestines of worms, after the breakdown 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, a fact noted by Charles Darwin. They dig holes 60-80 centimeters deep, thereby loosening the soil.
Today, people widely use worms for their own purposes. First of all, to obtain vermicompost. Worms are actively used in poultry and livestock farming for feeding. Worms are also widely used by amateur fishermen as good bait.
The structure of earthworms
The structure of earthworms quite simple. The length of individuals that are common in Russia varies from 2 to 30 centimeters. The entire 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, with the exception of the very first. There can be from 8 to 20 setae on one segment.
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In the attached picture you can visually observe the structure of the worm. You can determine the front part of the worm, where the mouth is, and the back part, where the anus is located. You can also notice segments.
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 protective mucus, which contains a large number of antiseptic enzymes. The brain is poorly developed. It consists of only two nerve ganglia. It is very common for worms to exhibit the ability to regenerate. For example, if you cut off his tail, after a while it will grow back.
Earthworms are hermaphrodites, each having both male and female reproductive organs. Reproduction occurs through the mating of two individuals. The genital organ of worms is a girdle; in size it occupies several anterior segments. The genital girdle is clearly visible on the body of the worm; it looks like a thickening. In this organ, the cocoon matures, from which small worms hatch after 2-3 weeks.
Types of earthworms
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 soil surface (litter), and the second type includes those that live and feed in the soil layers (burrow). The first species lives constantly on the soil surface; its representatives do not descend into soil layers that are below 10-20 centimeters.
Representatives of worms that belong to the second type develop their activities exclusively at a depth of 1 or more meters. If necessary, they stick out only the front part of their body from the ground.
The second species, in turn, can be divided into burrowing and burrowing worms. Burrowers live in deep layers of soil, but do not have permanent burrows. And burrow 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.
Lifestyle of worms underground
Worms are nocturnal. At this time of day you can observe their most active activity. At night they eat most of the food. Many crawl out to consume food, but rarely get out of their burrows completely - their tails always remain underground. During the day, 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 worms is very stretched, thanks to numerous segments. In addition, the worms have very tenacious bristles. In this regard, forcibly pulling him out of the mink is a rather difficult undertaking.
They are omnivorous. They have a very characteristic diet. First, they swallow a large amount of soil, and then absorb only useful organic substances from it.
Worms are able to digest even small quantities of animal feed, such as meat.
Eating of food occurs in burrows. First, the worm gropes for a tasty morsel from the outside and drags it into its hole, where the meal takes place. In order to capture the food object, the worm attaches itself very strongly to it, then pulls back with all its strength.
Moreover, the worms make a supply of food for themselves. They very carefully put it in their burrows. Worms can also deliberately dig another hole just to store food. They seal such a hole with damp soil and open it only if necessary.
It happens in the following order. First, the soil is swallowed, then the organic substances are digested inside the worm. After this, the worm crawls out and excretes excrement. Moreover, it stores waste products in one specific place. Thus, before entering the hole, a kind of pile 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 digging activities, as a result of which the layer of earth is always in motion. Worms have a very large appetite. In just one day, he can eat a volume of food that is comparable in weight to him, 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 facilitate better penetration of oxygen and water into it. Plant roots grow much better in worm holes.
As a result of constant loosening of the soil, large objects gradually sink deeper into the earth. Small foreign particles are gradually ground into the stomachs of worms and turn into sand.
Unfortunately, the number of earthworms in our country is declining. This is facilitated by the inappropriate 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 vermicompost?!
The role of earthworms in nature very large and unlikely to be overestimated. Worms play a huge role in the decomposition of organic matter. enrich the soil the most valuable fertilizer - 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. Until 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 wand for the soil. It contains very large amounts of potassium, phosphorus and nitrogen - substances that are primarily necessary for plant growth.
We've gone a little off topic. In wildlife, worms stay in places where there is a large amount of organic waste. A good example is the forest. When the leaves fall in the fall, they will need to go somewhere. Soil bacteria and, of course, earthworms will come to the rescue here. Immediately after the leaves fall, soil bacteria will get to work and decompose it to the compost stage. Then the worms will get to work and process the compost to the vermicompost stage and add this valuable fertilizer to the soil. In principle, this is how soil formation occurs.
The benefits of earthworms
During the Soviet Union, chemical mineral fertilizers began to be actively used in the Russian expanses, which over time destroy entire layers of soil. Today we have just come to the moment when the soil begins to rapidly collapse. Chernozem soils no longer give such good results as before. Unscrupulous farmers who think only about their income use fertilizers that are dangerous to the soil on their plots of land, thereby destroying it. But soil restoration takes a very long period of time, about 1 centimeter per 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 through the introduction and distribution of vermicompost. Even if the land does not need restoration, adding vermicompost to it will in any case be beneficial. It is impossible to contaminate chernozem or burn it with humus, unlike any other fertilizer. This is due to the fact that vermicompost has a very similar structure to chernozem. You can even say that humus is concentrated black soil.
With the help of worms you can bring great benefits to your vegetable garden, orchard or small household plot. To do this, you just need to learn how to breed worms yourself, and this is very easy 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 themselves. There is another option - buy worms. You can also breed worms in separate boxes. As organic waste is eaten, 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 the garden or garden it is necessary to create all the conditions for the development of worms. The most rational way would be to build a special box in which you can put all the weeds and other organic waste in the summer. Next year, if there are 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 simply scattering it around the area, others bury it, and still others even prepare a liquid fertilizer based on it. In general, there are many ways to use it.
Earthworms - Vermiculture
A fairly large number of farmers and ordinary people who have their own household plots are engaged in breeding earthworms for the purpose of obtaining vermicompost. And this trend is not encouraging. Vermiculture may soon replace harmful chemical fertilizers.
Breeding worms can also be considered a good business idea. At minimal cost, you can get the most valuable fertilizer and sell it for good money. It is especially beneficial to engage in this business for those who have poultry or farm animals and do not know what to do with their waste products. The droppings of farm animals are excellent food for worms, which turns into vermicompost.
In this part of the article, one cannot fail to mention the type of worm that is the most productive - the Californian one. California worms were bred in 1959 in the USA. These earthworms are the most commonly used in this area due to their enormous productivity. The Californian worm lives as long as a regular one, 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 introducing worms into the substrate, it must be prepared. It needs to turn into compost. It is most convenient to use ordinary metal barrels with a volume of 200 liters.
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At home, you can breed worms in various containers. A wooden box with small holes to drain excess water at the bottom is best suited for these purposes; the substrate is placed there and the worms are released. In one summer, a box of organic waste can be turned into vermicompost. See photo:
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You can use boxes of a different design, for example plastic ones, in which fruits and vegetables are transported:
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Earthworms video
“The appetizing fruits and vegetables you see are not fakes. These beautiful fruits are real, and most importantly, environmentally friendly. And all this is due to the fact that they were obtained using an amazing fertilizer - vermicompost.” In this video we will talk about earthworms of the “prospector” breed. The video is very useful and educational.
This video was shown on television, this is the Galileo program. The report was prepared about earthworms.
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To enlarge an image, simply click on it.
Since ancient times, humanity has paid special attention to such unsightly creatures as the earthworm. And scientific minds, in the person of Charles Darwin, decades later, studied their structure and significance in agriculture for many years. And not without reason. Indeed, with the onset of spring warmth, earthworms begin painstaking work and work, without knowing it, for the benefit of people.
Features and habitat
Earthworm , he is also a ringed one - a well-known resident on any personal plot. And it would seem an absolutely invisible creature that no one needs.
However, any person who is at least somehow connected with the land will be very happy to have such inhabitants of his garden. There are no more than a hundred species of earthworm in the Russian Federation. But all over the world there are one and a half thousand varieties of them.
It belongs to the family of annelids, the oligochaete class. Its entire long body consists of many rings. There may be seventy of them, or maybe all three hundred. Since it grows more than twenty-five centimeters in length.
But there are also the smallest ones, two or three centimeters. The Australian earthworms reach two and a half meters in size. Its color is literally gray-brown - crimson.
Also, on each ring, or it is also called a segment, there are bristles. Our ordinary garden worms, as a rule, grow eight bristles. They are classified as oligochaetes.
However, there are also tropical, polychaete species of worms in which the villi grow in dozens. The bristles help the worms crawl, absolutely over all soil tubercles or burrow into holes.
You can find them by holding the worm in your hands and running your finger from back to front. But since it is difficult for an inexperienced person to determine where his butt is, you can simply run your hand lightly along the body and back. You can feel it right away. In one direction the worm will be absolutely smooth, and in the opposite direction it will be rough.
Anyone who has ever picked up a worm knows that it is covered with not very pleasant mucus, which is vital for it. Firstly, mucus helps the invertebrate move freely in the ground. Secondly, since the worm does not have lungs, it breathes through the skin. And thanks to the moisture found on the mucus, the body is saturated with oxygen.
Self earthworm body consists of two groups of muscle tissue. They are longitudinal and transverse. The transverse muscles are located under the protective top layer of the worm's skin.
With their help, the worm becomes as long as possible. And the stronger muscles are longitudinal. They cut and make the body smaller. This is how the animal moves, sometimes lengthening, sometimes shortening.
The earthworm belongs to the secondary cavity animals. Consequently, he has a complete closed circulatory system. Because their life activity is active.
The muscles contract many times more often than in protocavitary worms. To do this, they need blood to provide the worm with all the nutrients and oxygen.
IN the structure of an earthworm there are a pair of blood vessels, one of them is called dorsal, the second abdominal. Ring vessels connect them to each other. Blood flows through them from back to front, and vice versa.
Each ring, or segment as it is also called, has a pair of tubes. The funnels at their ends open and feces are discharged through the bottom. earthworm. This is the principle of operation of the excretory system.
As for the nervous system, it is nodal. Its components are the ventral nerve cord and the peripharyngeal nerve ring. These endings consist of fibers, and they, in turn, respond to the urges of the contracted muscles of the worm. Thanks to them, the worm can eat, move purposefully, reproduce, and develop.
In the building earthworm organs those responsible for smell, touch, vision, sensation are absent. But there are certain cells, they are located along the entire body of the invertebrate. With their help, the worm navigates in the dark and impassable ground.
Character and lifestyle
Charles Darwin also suggested the presence of intelligence in earthworms. Watching them, he noticed that when dragging a dry leaf into his home, it was turned with the narrow side. This makes it easier for a leaf to pass through a dense, earthy burrow. But on the contrary, he takes spruce needles by the base so that they do not fork.
All day, all life of rain worm scheduled by the minute. Every now and then he climbs in the ground, makes moves, swallowing it. The worm digs holes in two ways. He or, as already mentioned, swallows the earth, gradually moving forward.
In case the ground is too hard. And then leaving behind their biological waste. Or, he pushes it with his delicate end in different directions, and makes moves for himself. The passages are obliquely vertical.
Same rain worm, subsistence in the soil, drags into its holes, for insulation, various leaves, veins from leaves, thin pieces of paper and even scraps of wool. Its burrows are up to one meter deep. And the worms are larger in size, and all ten meters. The worm works mainly at night.
A why earthworms crawl to the surface in huge quantities. This means he can't breathe. This usually happens after heavy rains. The earth is clogged with moisture, and there is no oxygen for him at all. When the cold weather arrives, earthworm goes deep into the soil.
Earthworm nutrition
The worm's diet is quite typical. Ingesting large quantities of soil along with food. Withered and slightly rotten leaves and mushrooms are suitable for them to eat. But it should not have an unpleasant odor, otherwise the worm will not eat it.
It turns out that earthworms even build entire storage rooms for themselves and store food there for winter. They eat it only in case of critical need. For example, in winter, when the ground is completely frozen, and there is no talk of any terrestrial food.
Having sucked in the food along with a lump of earth, through the pharynx, with muscular movements, now expanding his body, now narrowing it, he pushes it to the back of the esophagus into the goiter. Afterwards, it penetrates the stomach. From the stomach it is sent to be poisoned in the intestines, thanks to enzymes, and comes out as useful biomass.
Making moves, and at the same time having a snack, rain worm need to crawl out periodically to the surface to throw off the earth. At the same time, he adheres to the hole with his tail edge, as if holding on to it.
And after that, there are always earthen slides. The soil processed by the worm turns out sticky. Then it dries and becomes small balls, about the size of a match head.
These balls are saturated with vitamins, enzymes, and organic substances, which, as a result, kill all bacteria in the soil and prevent rotting, which is very important for plant roots. And they also act on the composition of the earth as an antiseptic, disinfecting it.
Reproduction and lifespan
Earthworms can be heterosexual or hermaphrodite. All earthworms have thickenings on the front third of their body. They contain the ovary and testis. Hermaphrodites release seed into each other. Already ripe testicles, up to ten pieces, are inseminated. And they crawl away in different directions.
When a female individual is ready to reproduce, she approaches her partner and copulates. Something like a cocoon is formed on it, consisting of several dozen thickened segments.
It is divided by a kind of belt. This cocoon receives all the nutrients necessary for the brood. After fertilization, the worm takes off this burden; it simply slides off the animal.
The edges of the cocoon are quickly pulled together on both sides so that the future offspring do not dry out before they are born. Then, over the course of four weeks, small worms mature and hatch.
Once born, they scatter in all directions. And from the first days of their lives they begin active work to process the land. And already at three months of age, grown-up children reach the size of adults.
Another fact about earthworms is the ability to regenerate. If someone or something splits it into two halves. Over time, each half will become a full-fledged individual. This is one of the methods of reproduction, but no longer sexually.
The role of the earthworm very important in agriculture. Firstly, they saturate the soil with oxygen, which is so necessary for everything growing on it. With their moves, they help the roots to fully develop.
Moisture is distributed evenly, and the soil is well ventilated and loosened. Thanks to the constant movement of the earth, with the help of worms, stones are removed from it.
Also, with their recycled adhesive residues, they glue the soil together, preventing it from eroding. Well, and of course they fertilize the soil when leaves and insect larvae are drawn into it. It all rots and serves as excellent, natural biological additives.
The rain cervix has an elongated body, 10-16 cm long. In cross-section, the body is round, but, unlike roundworms, it is divided by annular constrictions into 100-180 segments. Each segment has small elastic bristles. They are almost invisible, but if we run our fingers from the back end of the worm's body to the front, we will immediately feel them. With these bristles, the worm clings to uneven soil when moving.
Figure: earthworm and worm movement in soil
Earthworm Habitat
During the day, worms stay in the soil, making tunnels in it. If the soil is soft, then the worm drills it with the front end of the body. At the same time, he first compresses the front end of the body so that it becomes thin, and pushes it forward between the lumps of soil. Then the front end thickens, pushing the soil apart, and the worm pulls up the rear part of the body. In dense soil, the worm can eat its way through the soil through its intestines. Heaps of earth can be seen on the surface of the soil - they are left here by worms at night. They also come to the surface after heavy rain (hence the name rain). In summer, worms stay in the surface layers of the soil, and in winter they dig burrows up to 2 m deep.
Skin-muscle bag
If we take a worm in our hands, we will find that its skin is moist and covered with mucus. This mucus facilitates the movement of the worm in the soil. In addition, only through moist skin does the oxygen necessary for breathing penetrate into the worm’s body.
Under the skin there are circular muscles fused with it, and under them a layer of longitudinal muscles - a skin-muscular sac is obtained. The circular muscles make the body of the worm thin and long, while the longitudinal muscles shorten and thicken. Thanks to the alternating work of these muscles, the movement of the worm occurs.
Body cavity of an earthworm
Figure: internal structure of an earthworm
Under the skin-muscle sac is a fluid-filled body cavity in which the internal organs are located. This body cavity is not continuous, like in roundworms, but is divided by transverse partitions according to the number of segments. It has its own walls and is located under the skin-muscle sac
Digestive organs of an earthworm
Picture: Digestive system of an earthworm
The mouth is located at the anterior end of the body. The earthworm feeds on rotting plant debris, which it swallows along with the soil. It can also drag fallen leaves from the surface. Swallowing is done by the muscular pharynx. The food then enters the intestines. Undigested remains, along with soil, are expelled through the anus at the rear end of the body.
Figure: circulatory system of an earthworm
The earthworm's circulatory system serves to transport oxygen and nutrients primarily to the muscles. An earthworm has two main blood vessels: dorsal blood vessel, along which blood moves from back to front, and abdominal blood vessel, through which blood flows from front to back. Both vessels in each segment are connected to annular vessels. Several thick annular vessels have muscular walls, due to the contraction of which blood moves. From the main vessels, thinner ones depart, which then branch into the smallest capillaries. These capillaries receive oxygen from the skin and nutrients from the intestines, and these substances are released from other similar capillaries that branch in the muscles. Thus, the blood moves all the time through the vessels and does not mix with the cavity fluid. Such a circulatory system is called a closed circulatory system.
Excretory system of an earthworm
Liquid unnecessary, processed substances enter the body cavity. Each segment contains a pair of tubes. Each tube has a funnel at the inner end; processed waste substances enter it and are discharged through the tube through the opposite end to the outside.
Picture: earthworm nervous system
A pair of nerve trunks runs along the entire body of the worm along the ventral side. In each segment they have developed nerve nodes- it turns out nerve cord. In the front part, two large nodes are connected to each other by ring jumpers - a peripharyngeal nerve ring. Nerves extend from all nodes to various organs.
Sense organs of an earthworm
There are no special sense organs, but sensitive cells in the skin allow the earthworm to sense touch on its skin and distinguish light from dark.
Reproductive system and reproduction of the earthworm
Earthworms are hermaphrodites. Before laying eggs, two worms come into contact for a while and exchange seminal fluid - sperm. Then they disperse, and mucus is released from the thickening (belt) located on the front of the worm. This mucus contains eggs. Then a lump of mucus with eggs slides off the worm's body and hardens into cocoon. Young worms emerge from the cocoon.