In the world of fauna is the earthworm. He can rightfully be called an earth worker, since it is thanks to him that the soil on which we walk is completely saturated with oxygen and other minerals. By passing through various sections of the ground lengthwise and crosswise, this worm makes them loose, which then makes it possible to plant cultivated plants there, as well as to do gardening.

General characteristics of the species

The earthworm belongs to the kingdom Animalia, to the subkingdom Multicellular. Its type is characterized as Ringed, and its class is Oligochaete. The organization of annelids is very high compared to other types. They have 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 airbag for the animal. Also, thanks to them, each individual segment of the worm’s body can exist autonomously and progress in development. The habitats of these earthly orderlies are wet soil, salty or fresh water.

External structure of an earthworm

The worm's body is round in shape. 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 worm's body has a small thickening in which the so-called genital organs are concentrated. Local cells are activated during the breeding season and perform the function of laying eggs. The lateral outer parts of the worm's body are equipped with short bristles, completely invisible to the human eye. They allow the animal to move in space and move through the ground. It is also worth noting that the tummy earthworm It is always painted in a lighter tone than its back, which has a dark burgundy, almost brown color.

What is he like from the inside?

The structure of the earthworm differs 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 containing iron. This layer is followed by muscles, which are divided into two categories: circular and longitudinal. The former are located closer to the surface of the body and are more mobile. The latter are used as auxiliary during movement, and also allow you to work more fully. internal organs. The muscles of each individual segment of the worm's body can function autonomously. When moving, the earthworm alternately compresses each ring group of muscles, as a result of which its body either stretches or becomes shorter. This allows him to dig new tunnels and fully loosen the ground.

Digestive system

The structure of a 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, products are purified from acids released by rotting products. The food then passes through the crop and into the stomach, which contains many small muscles. Here the products are literally ground up and then enter the intestines. The worm has one midgut, which goes into the posterior opening. In its cavity, all useful substances from food are absorbed into the walls, after which waste leaves the body through the anus. It is important to know that earthworm excrement is rich in potassium, phosphorus and nitrogen. They perfectly nourish the earth and saturate it with minerals.

Circulatory system

The circulatory system possessed by an earthworm can be divided into three segments: the abdominal vessel, the dorsal vessel and the annular vessel, which combines the previous two. The blood flow in the body is closed, or circular. The annular vessel, which is shaped like a spiral, unites two vital arteries for the worm in each segment. Capillaries also branch 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 driven from the abdominal artery to the dorsal one. 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 the nervous system

The earthworm's breathing process occurs through the skin. Each cell of 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 reservoirs 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 analogues, smaller in size, are present in each of them. Therefore, each segment of the worm’s body can exist autonomously.

Reproduction

Let us immediately 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 part of the body, and during the mating period (and it is cross-breeding), 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 will feed the embryo. As a result of these processes, a mucous membrane is formed in which embryos develop. Afterwards they leave it, back end first, and crawl into the ground to continue their lineage.

Earthworms are worms with smooth body walls, with a body of many small segments. If you look at its body, you can see lines marking the segments. Each segment has stiff hairs that help the worm move, sometimes the hairs are difficult to see. They do not have a skeleton, but their body has many muscles. Earthworms do not have many pigments for coloring, so they typically appear white, gray, pink, brown, or reddish. Some worms have red blood and you can see it through the skin. Their skin produces a slimy substance that helps them glide through the soil. Like most animals, they have a front and a back, and their mouth and tiny brain are at the front of their body. They do not have eyes or a nose, but can detect light and vibrations, and they have senses of touch and taste. Some types of worms are very small, less than 1 mm long, but some of them are the most big worms in the soil. IN North America The longest worms reach almost 30 cm, and in Australia there are some species that grow over 2 meters long!
Where do they live?
Earthworms and their aquatic relatives are found throughout the world. There are several thousand species! Most of them live in dirt and filth around fresh water, but some live in the sea, and many live in the soil on land. This post is mainly about earthworms that live on the ground. There are at least 21 species of earthworms in Michigan. Some of the largest and most common species of earthworms in North America were accidentally brought there by colonists from Europe.
What living conditions do they need?
Earthworms and their relatives live wherever there are wet soil and dead plant material. Earthworms are most common in rain forested areas, but can be found in many land and freshwater habitats. All types of worms require moist soil conditions to survive.
Most species of earthworms live within a meter top layer soil, and spend most of their time just below the soil surface, where there is a lot of decomposed plant matter. Some species appear on the surface of the earth at night, when it is sufficiently wet. They move deeper to avoid drought or winter freezing. Some species never come to the surface, and spend their entire lives many meters below the surface. The tunnels of these worms have been found at least 5 meters (16.5 feet) below the surface!
These animals are found in the following types of temperate habitats tropical climate near fresh water sources:
Taiga, savannas or meadows, forests, forested mountains.
Aquatic biomes lakes and ponds, rivers and streams.
Wetlands, swamp.
Urban, suburban, agricultural land.
How do they reproduce?
Earthworms lay their eggs in cocoons they make in the soil. The little worms that hatch are like tiny versions of the adults and they won't change much when they grow up, they just get bigger. Species that live in very cold or hot and dry environments climatic conditions, can hibernate when they are too cold or dry.
How long do they live?
Some types of worms can live up to 8 years, but it is very rare for them to survive that long. Most are eaten by predators or killed in some other way before they live for one year.
How do they behave?
During the day, earthworms mostly remain in their burrows underground. At night they come to the surface to feed. If the air is too cold or too dry, they remain down in the soil. Some species also come to the surface during the day if it rains.
How do they communicate with each other?
Earthworms communicate with each other only by touch and taste, but they can sense vibrations and often avoid predators by sensing their movements. They can also sense light and moisture in the air.
What do they eat?
Earthworms eat dead and decaying plant material, mostly leaves but also tiny roots. Some species live deep in the soil and feed on dead roots.
Predators of earthworms
The main defense of earthworms is to hide in holes in the ground. They quickly slide down into the ground if they detect a predator. Some may release harmful chemicals. Some of them can grow a new tail.
Known predators of earthworms:
Starlings.
Robins.
Crows.
red and blackbirds.
Other birds that feed on the ground.
Foxes.
Shrews.
Mol.
Skunks.
Snakes.
Skinks.
Salamanders.
Frogs.
Toads.
Ground beetles.
Ants.
Centipedes.
Cancers.
Snails (eat cocoons).
ticks (feed on eggs).
What role do they play in the ecosystem?
Earthworms are very important for the soil. They carry organic material down to lower levels, they rid the soil of dead plant material, and their burrows help bring air and water deeper into the soil.
Are they causing problems?
Earthworms sometimes damage seedlings of valuable plants, and their movement in the soil can spread plant diseases. Some worms also carry animal parasites that grow in their bodies.
How do they interact with people?
Earthworms are generally very beneficial. Tunneling and feeding them helps enrich the soil, promoting better plant growth.
Are they under threat?
Earthworms as a group are very common, abundant, and do not require special protection. We don't know very much about most species, so some rare species may be in danger.
It is not true that if you cut a worm into pieces, the individual parts will grow. Sometimes they can grow a new tail, but not a whole organism. Worms that come during rainstorms look for new places to live and often become trapped in puddles. They can live in water (they get oxygen through their skin), but they will die from too much large quantity sunlight, or if there is salt or other toxic chemicals in puddles.
Some people keep boxes of worms in the dirt. They feed the worms kitchen scraps and then place the worms and dirt in their gardens.

Animals, suborder earthworms. The body of an earthworm consists of ring-shaped segments, the number of segments can reach up to 320. When moving, earthworms rely on short bristles, which are located on the body segments. When studying the structure of an earthworm, it is clear that, unlike the whipworm, its body looks like a long tube. Earthworms are distributed throughout the planet, except Antarctica.

Appearance

Adult earthworms are 15–30 cm in length. 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 rings - segments. This shape of the worm’s body is explained by its way of 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 abdominal side. Approximately where the front part of the body ends, the worm has a thickening called the girdle. It contains special glands that secrete a sticky liquid. During reproduction, an egg cocoon is formed from it, inside which the worm eggs develop.

Lifestyle

If you go out into the garden after rain, you can usually see small piles of earth thrown out by earthworms on the path. Often the worms themselves crawl along the path. It is precisely because they appear on the surface of the earth after rain that 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 in sandy soils. He also does not live in swamps. Such features of its distribution are explained by the way it breathes. An earthworm breathes over the entire surface of its body, which is covered with mucous, moist skin. There is too little air dissolved in the water, and therefore the earthworm suffocates there. It dies even faster in dry soil: its skin dries out and breathing stops. In warm and humid weather, earthworms stay closer to the surface of the earth. During prolonged drought, as well as cold period they crawl deep into the ground.

Moving

An earthworm moves by crawling. At the same time, it first retracts the front end of the body and clings to uneven soil with bristles located on the ventral side, and then, contracting the muscles, pulls up the rear end of the body. Moving underground, the worm makes passages in the soil. At the same time, he pushes the earth apart with the pointed end of his body and squeezes between its particles.

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

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

The muscles of an earthworm are located in two layers. Under the skin lies a layer of circular muscles, and below them is a thicker layer of longitudinal muscles. Muscles are made up of long contractile fibers. When the longitudinal muscles contract, the body of the worm becomes shorter and thicker. When the circular muscles contract, on the contrary, the body becomes thinner and longer. By contracting alternately, both layers of muscles cause the movement of the worm. Muscle contraction occurs under the influence nervous system, branching 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 moistened in water along the sides and along the ventral side of the worm's body, from the rear end to the front. With the help of these bristles, the earthworm moves underground. They also hold him back 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-rotted plant remains. They drag leaves, stems, etc. into their burrows, usually at night. Earthworms also feed on humus-rich soil, passing it through their intestines.

Circulatory system

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

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

Irritation

The earthworm has no special sense organs. It perceives external irritations with the help of the nervous system. The earthworm has the most developed sense of touch. Sensitive tactile nerve cells located over the entire surface of his body. The sensitivity of the earthworm to various kinds of external irritation is quite high. The slightest vibrations in the soil cause it to quickly hide, crawling into a hole or into deeper layers of soil.

The importance of sensitive skin cells is not limited to the sense of touch. It is known that earthworms, without special organs of vision, still perceive light stimulation. If you suddenly shine a flashlight on a worm at night, it quickly hides.

The animal's response to stimulation, carried out using the nervous system, is called a reflex. There are different types of reflexes. The contraction of the worm's body when touched and its movement when suddenly illuminated 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. Charles Darwin discovered that earthworms can smell the leaves of the plants they feed on.

Reproduction

Unlike hydra, earthworms reproduce exclusively sexually. It does not reproduce asexually. Every earthworm has male organs- testes, in which the living creatures 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 worm's girdle. In the form of a muff, the cocoon slides off the worm and is pulled together at the ends. In this form, the cocoon remains in the earthen burrow until the young worms emerge from it. The cocoon protects the eggs from dampness and other unfavorable influences. Each egg in the cocoon divides many times, as a result of which 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.

The common earthworm is of great importance for increasing soil fertility, and is also an important part of the diet of many birds and mammals.

   Class - Oligochaetes
   Family - Lumbricidae
   Genus/Species - Lumbricus terrestris

   Basic data:
DIMENSIONS
Length: usually up to 30 cm, sometimes more.

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

LIFESTYLE
Habits: singles; on cold or dry days they lie motionless in the ground.
Food: earth that contains remains of organic matter, sometimes small carrion.
Lifespan: in captivity up to 6 years.

RELATED SPECIES
There are about 300 species of the true earthworm family. Their closest relatives are leeches and marine polychaete worms.

   An ordinary earthworm gnaws its way through the ground. Thanks to the activity of earthworms, a fertile layer of soil has been formed over millions of years. IN rainy weather These animals can be seen on the surface of the earth, but catching a worm is not easy, since thanks to its developed muscles it instantly disappears underground.

REPRODUCTION

   Each earthworm has male and female genital organs in its body, that is, it is a hermaphrodite. However, 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 part of one is pressed against the rear end of the other. Earthworms are covered with a mucous membrane, under which sperm exchange occurs. Having separated from each other, earthworms take part of the shell, which gradually becomes denser, and then slowly slides off the body to the anterior end, where fertilization occurs.
   When the shell slides off the worm's body, it closes tightly 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

   At any time of the day on the lawn or in the clearing you can see a starling or a blackbird and a songbird, who, bowing their heads, listen to see if there is a worm somewhere nearby underground. However, a caught earthworm can defend itself. The bristles on its body and powerful circular and longitudinal muscles help the rain worm stay in the ground.
   Especially large and strong earthworms sometimes manage to escape from the beak of a bird. Sometimes only a piece of an earthworm remains in the bird's beak. If this is the back part of the worm's body, then the animal usually survives and grows back the lost part of the body. Ordinary worms become prey for hedgehogs, badgers, foxes and even wolves. However, their main enemy is the mole, which also lives underground.

LIFESTYLE

   An earthworm spends most of its life underground. It digs a network of underground corridors that can reach a depth of 2-3 m. The earthworm's body consists of segments. Beneath the skin are two layers of muscle. 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 or compress and thicken it.
   The earthworm, straining the annular muscles in the front of the body, moves forward. A wave of muscle contractions then passes through the body to move the back part 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. Thanks to the mucus secreted, the earthworm can move in very hard soil. Sunlight poses a serious danger to earthworms, since they are covered only with a thin layer of skin. Worms are not protected from exposure ultraviolet radiation, so they appear on the surface only in rainy weather. Very often they go out on rainy nights to collect pieces of straw, paper, feathers, leaves on the ground and pull them into their burrow.

FOOD

   Many species of animals look for food in the ground, but the earthworm eats the ground itself. He eats organic substances located in the soil. The worm kneads the earth in the muscular stomach, digests some of it, and excretes the remainder in the form of stool. Some species excrete their feces on the surface of the ground in small piles visible to the naked eye, others excrete undigested remains underground.
   Most of all, earthworms love the soil 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 remains that decompose. A large concentration of earthworms in the soil is a guarantee of its productivity. Earthworms live in neutral and alkaline soils. In acidic soil, for example, near 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 them there.
  

DID YOU KNOW THAT...

• In 1982, an earthworm 1.5 m long was found in England. However, it is significantly smaller than the Australian and South American species (their length is 3 m).
• Fossil worms resembling modern earthworms have been found in geological layers that are approximately 600 million years old.
• If an ordinary earthworm loses the end of its body, it often grows a new one. However, two parts will never produce two earthworms. An ordinary earthworm that is cut in half dies.
• Based on weighing the waste of ordinary earthworms over an area of ​​1 m2 over the course of a year, we can conclude that an earthworm carries 6 kg of excrement to the surface of the earth during this time.

  

HOW DO EARTHWORMS REPRODUCE?

   Pairing: earthworms are hermaphrodites. They find each other by smell and, connected by a mucous membrane, exchange sperm on the surface of the earth.
   Appearance of mucous membrane: mucus is secreted from the girdle - a light, thickened part at the anterior end of the body, into which numerous glands open. The mucus secreted forms the mucous membrane.
   Fertilization: The mucous membrane moves throughout the body and collects eggs and sperm.
   Mucous membrane: through the head and slides off the body of the worm.
   Cocoon: a slimy container containing up to 20 eggs closes and forms a cocoon that can withstand even extreme unfavorable conditions. Most often, only one earthworm hatches from it.

PLACES OF ACCOMMODATION
Earthworms are found all over the world. Common earthworms live throughout Europe and Asia, wherever they find the right soil and climate conditions.
SAVE
Some gardeners kill earthworms to remove traces of their activity. By doing this, they harm the entire ecosystem.

EARTHWORM

The earthworm family consists of almost 170 species and belongs to the phylum annelids– Annelides. All earthworms are similar in their lifestyle. They live in damp places, swarming tunnels underground, and in cold and drought they go deep into the ground. After heavy rains due to lack of air, earthworms are forced to rise to the surface. They feed on decaying plant debris and soil microorganisms. There are especially many earthworms in the soil of gardens, vegetable gardens and other soils, where their number can reach 400 pieces per 1 m of soil. Size from 8 to 30cm. Earthworms are hermaphrodites. They reproduce sexually using cross-fertilization (mutually fertilizing each other). The eggs are laid in a mucous cocoon, from which up to 10 embryos emerge.
Ground or common earthworm (crawl) - Lumbricus terrestris. 9-30 cm in length. It has a pink color and a dark pointed head end. The color fades towards the slightly flattened tail. Belt from the 31st-32nd to the 37th segment. Widely distributed. It is especially common in clay soils. On humid nights it comes to the surface for plant remains. In aquarium farming, this type of worm is most often used as food.
Tetrahedral earthworm - Eiseniella tetraedra. 3-5 cm in length. The middle and posterior parts of the body are noticeably tetrahedral. The belt occupies from the 22-25th to the 26-27th segment. It is found only in very wet habitats, for example in damp soil, in damp moss, near bodies of water. It reproduces parthenogenetically (virgin reproduction without the participation of males).
Yellowish-green earthworm -Allophora chlorotica. 5-7 cm in length. Belt from the 28-29th to the 37th segment. The color is different - yellowish, greenish or reddish. Lives in both slightly damp and very damp soil (in gardens, river bank cliffs), and in rotting foliage.
Reddish earthworm - Lumbricus rubellus. 7-15 cm in length. The dorsal side is reddish-brown and purple with a pearlescent tint. Belt from the 26-27th to the 32nd segment. A typical inhabitant of more or less moist humus soil (usually at shallow depths).
Earthworms (Lumbricidae)- are good food for large aquarium fish such as cichlids, koi, tetragonopterus, rheas and goldfish different breeds. They can be used in feeding aquarium fish, both whole and in crushed form. But constant feeding of them leads to fish obesity and infertility. Therefore, it is advisable to use earthworms for feeding 1-2 times a week, alternating the diet with other types of food.