Annelids have the following aromorphoses: 1. The body was divided into segments (metameres) with repeating sets of internal organs. 2. A secondary cavity has appeared - the coelom, which has its own mesodermal lining. 3. There was a further complication of the nervous system: the concentration of nerve cells on the abdominal side in each segment (the abdominal nerve chain was formed), a significant increase in the cerebral ganglia (nodes) (supraglottic, subpharyngeal nerve ganglia, peripharyngeal ring). 4. A closed circulatory system emerged, which ensured rapid transport of substances throughout the body. 5. Appeared respiratory system, increasing the respiratory surface and the intensity of gas exchange. 6. The digestive system has become more complex: the midgut has differentiated into sections, which has led to a step-by-step process of digestion. 7. Parapodia were formed - limbs for movement. 8. Further complication of the excretory organs occurred: a metanephridial multicellular excretory system was formed.

• Earthworm

Earthworm – Lumbricus terrestris(type Annelids, class Oligochaetes, family Lumbricidae) lives in moist, humus-rich soil. It feeds on organic matter, passing soil and plant debris through its intestines. Even Charles Darwin noted the beneficial effect of earthworms on soil fertility. By dragging the remains of plants into the burrows, they enrich it with humus. By making passages in the soil, they facilitate the penetration of air and water to the roots of plants.

Active earthworms in the warm season. In winter they hibernate. Freezing kills the worms instantly, so they must burrow deeper into the ground, where low temperatures do not penetrate. In the spring, when the temperature reaches a suitable level and the ground is saturated with rainwater, their mating season begins. They reproduce very quickly, producing about a hundred young worms per year. In summer, worms are not as active. There is very little food - dying plant debris - at this time, and the soil is deprived of moisture, which can cause the death of worms. Autumn period again characterized by worm activity. At this time, reproduction of offspring begins again, which lasts until the onset of winter.

Earthworms live relatively long. Some manage to live for about ten years if they do not become victims of birds and moles. Another threat to their life is the pesticides that are so widely used in gardening today.

So, the earthworm has an elongated, cylindrical body from 10 to 30 cm long. Dorsal side more rounded, it is darker, the dorsal blood vessel is visible through its skin. Abdominal side somewhat flattened and lighter colored. The anterior end of the body is thicker and darker in color. The body consists of rings - segments. In an adult worm, their number reaches 200. In the area of ​​32-37 body segments there is belt, rich in mucous glands. External segmentation corresponds to the division of the body cavity by partitions into separate chambers and the segmental (i.e. in each segment) arrangement of a number of internal organs. On each segment 8 bristles(they are easy to detect if you run your finger along the body of the worm in the direction from the rear end of the body to the front). The setae are arranged in four pairs on the lateral sides of the segments. Clinging to uneven soil, the worm moves forward with the help of the muscles of the skin-muscular sac.

Veils. Body earthworm covered skin-muscle bag. He is educated cuticle, single layer epithelium and two layers of muscles - external circular and internal longitudinal. The skin epithelium of the worm is rich mucous glands, which produce slime, covering the entire body of the worm and protecting it from drying out. Mucus also makes crawling in burrows easier by reducing friction with the soil.

Movement of an earthworm. When a worm crawls, waves of muscle contractions run through its body, and both the length and thickness of individual parts of its body are constantly changing. The movements produced by each part of the body consist in the fact that its constituent segments either stretch and become thinner, or contract and become thicker. As a result of such alternating stretching and contraction, the worm gradually moves forward: first, its head end is pulled forward, and then the posterior segments of the body are gradually pulled towards it; after this, the rear end of the body remains in place, and the head end is pushed even further forward, and thus the further advancement of the worm continues (it is convenient to observe it by letting the worm crawl along paper spread on the table).

• Body cavity. Inside the skin-muscle sac of annelids there is secondary cavity body, or in general. This body cavity is not limited by muscles, as in roundworms, but has its own epithelial(coelomic) lining, i.e. inner side The longitudinal muscles are lined with epithelium of mesodermal origin, and there is also an epithelial lining on the side of the intestine lying in the body cavity. Due to the coelomic epithelium, internal two-layer transverse partitions are formed between the segments - dissepiments. The secondary cavity is divided into chambers, each segment containing a pair of coelomic sacs. The coelomic fluid is under pressure and plays a role hydroskeleton, so the worm feels elastic to the touch.

Digestive system comprises front, average And rear guts. Mouth located on the second segment on the ventral side of the body. Anal hole

type Annelids Earthworm

At the posterior end of the body, it looks like a small slit. Due to feeding on rotting plant remains and humus, the digestive system has a number of features. Its anterior section is differentiated into muscular throat, esophagus, goiter and muscular stomach. To increase the absorption surface, a fold has formed on the upper part of the intestine typhlosol(typhlozolis). Please note: differentiated sections of the foregut - pharynx, esophagus, crop, stomach - were absent in previous types of worms.

Breath. An earthworm breathes over the entire surface of its body due to the presence of a dense subcutaneous network of capillary blood vessels. Therefore, it is important that the worm’s body covers do not dry out, but excessive moisture (for example, very wet soil after rain) is just as destructive for them.

Circulatory system closed, that is, blood moves through the vessels without spilling into the body cavity. The movement of blood is determined by the pulsation of large vessels, mainly girdling the esophagus. These are kind of hearts. Blood supplies all organs and tissues with nutrients, transporting them from the intestines, and oxygen entering the skin capillaries from external environment. By spinal vessel blood moves from the back end of the body to the front, and along abdominal vessel- in the opposite direction. An earthworm's blood is red. An iron-containing protein, similar to vertebrate hemoglobin and transporting oxygen, is found in a dissolved state in the blood plasma, and red blood cells are absent.

Nervous system more complex than that of flatworms and roundworms. It consists of peripharyngeal nerve ring with ganglia and abdominal nervous chains. This is the so-called nervous system ladder type. Suprapharyngeal doubles ganglion performs the functions of the brain and is more developed than subpharyngeal. The nerve chain originates from the subpharyngeal node and consists of segmentally located pairs of ganglia, connected to each other by transverse and longitudinal commissures. Nerves extend from the ganglia to various organs. The earthworm's sense organs are poorly developed: there are no eyes or tentacles, but their skin contains numerous sensory cells and nerve endings.

Excretory organs presented segment by segment (i.e. in each segment) arranged in pairs metanephridia. They look like convoluted tubes and begin in the body cavity as a funnel with cilia. A channel departs from the funnel, which penetrates the transverse septum and passes into the cavity of the next segment. The terminal section of the metanephridium has an extension - uric bubble, which opens outward on the side of the worm’s body (i.e., in each segment there is a pair of very small excretory holes). In addition to metanephridia, the secretion involves chloragogenous cells, covering the surface of the intestine with a thin brown-yellow coating. Chlorogenic cells accumulate excretion products. Filled with metabolic products, these cells die, and their contents enter the body cavity, from where they are removed by metanephridia.

Reproduction. Earthworms hermaphrodites. The reproductive organs and girdle can be examined only during the breeding season - in the spring. To male

type Annelids Earthworm

the reproductive system includes two pairs of testes, located in segments 10 and 11, four vas deferens, which merge in pairs and open outwards doubles male sexual hole, located in the 15th segment. The female reproductive system includes pair ovaries located in segment 13, oviducts, which open outwards in the 14th segment a couple women's sexual holes. There are two pairs in segments 9 and 10 spermatheca, each of which opens outward with an independent hole.

Earthworms reproduce sexually. Cross fertilization, in a cocoon. Two worms meet, tightly wrap their bodies around each other, attach their ventral sides to each other and exchange sperm, which ends up in the spermatic receptacles. After this, the worms disperse. Next, the belt forms a mucous muff, in which eggs are laid. As the coupling moves through the segments containing the spermatheca, the eggs are fertilized by sperm belonging to another individual. The muff is shed through the anterior end of the body, becomes compacted and turns into an egg cocoon, where young worms develop.

Regeneration. Earthworms are characterized by a high ability to regenerate, i.e. From each piece of the torn body of an earthworm, a whole worm is restored.

Questions for self-control

Name the aromorphoses of the annelid type.

Name the classification of the type Annelids.

What is the systematic position of the earthworm?

Where do earthworms live?

What body shape do earthworms have?

What is the body of an earthworm covered with?

What body cavity is characteristic of an earthworm?

What is the structure of the worm's digestive system?

What is the structure of the worm's circulatory system?

How does an earthworm breathe?

What is the structure of the worm's excretory system?

What is the structure of the worm's nervous system?

What structure does it have? reproductive system earthworm?

How does an earthworm reproduce?

What is the significance of an earthworm?

type Annelids Earthworm

Rice. Earthworm, its passages in the ground and movement.

Rice. Internal structure of an earthworm.

1, 16 - intestine; 2 - partitions; 3 - epithelial lining of the secondary body cavity; 4 - dorsal (back) blood vessel; 5 - ring blood vessel; 6 - skin-muscle bag; 7 - cuticle; 8 - skin epithelium; 9 - whole; 10 - metanephridium; 11 - eggs; 12 - ring muscles; 13 - longitudinal muscles; 14 - ventral (abdominal) blood vessel; 15 - abdominal nerve cord.

type Annelids Earthworm

Rice. The structure of the anterior end of the earthworm's body.

The prostomium is the protrusion of the upper part of the first segment, covering the mouth. Peristomium is the name of the first segment of the body.

type Annelids Earthworm

Rice. The structure of an earthworm.

A - head end; B - internal structure; B - nervous system.

1 - mouth opening; 2 - male genital opening; 3 - female genital opening; 4 - belt; 5 - pharynx; 6 - esophagus; 7 - goiter; 8 - stomach; 9 - intestines; 10 - dorsal blood vessel; 11 - ring blood vessels; 12 - abdominal blood vessel; 13 - metanephridia; 14 - ovaries; 15 - testes; 16 - seed sacs; 17 - seminal receptacles; 18 - peripharyngeal nerve node; 19 - peripharyngeal nerve ring; 20 - abdominal nerve chain; 21 - nerves.

type Annelids Earthworm

Rice. Longitudinal section of the body of an earthworm.

1 - mouth; 2 - pharynx; 3 - esophagus; 4 - goiter; 5 - stomach; 6 - intestine; 7 - peripharyngeal ring; 8 - abdominal nerve chain; 9 - “hearts”; 10 - dorsal blood vessel; 11 - abdominal blood vessel.

Rice. Reproduction of the Earthworm.

1 - mucous coupling; 2 - cocoon; 3 - emergence of young worms from the cocoon.

type annelids

Rice. Structure Polychaete worm Nereids.

type annelids

Rice. Appearance of a Medical leech.

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. The earthworm usually 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 of the nervous system, which branches out in 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 a circulatory system that the 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, the blood carries carbon dioxide from the tissues into the skin. 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 are located throughout the 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 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. Asexual reproduction he doesn't have. Each earthworm has male organs - the testes, in which the worms develop, and female genital organs - the ovaries, in which the 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.

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 secondary cavity body, which has its own digestive systems, circulatory and nervous. 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 has round 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 earthworm’s tummy 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 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 spinal 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 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. Nervous system 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.

Class: 7

Subject: Laboratory work No. 1 on the topic “Study of the structure of annelids”

Org moment: mutual greeting.

Knowledge test: survey on the topic of the type of annelids.

What sections can the body of an annelid worm be divided into? (head, body, tail)

Why were they given such a name (their body consists of segments)

Dimensions? (0.5mm-3m)

Symmetry (two-way)

How many layers of cells does their body consist of (three)

What muscles do they have (circular and longitudinal)

Parapodia (something like legs)

What appears for the first time (circulatory system)

What parts does the digestive system consist of? (mouth, pharynx, esophagus, crop, stomach, mid and hind intestine, anus)

Breath?

Nervous system? Peripharyngeal nerve ring with a branch in each segment)

Reproduction? (asexual and sexual)

What is a belt? (the place where fertilized eggs arrive).

Type of annelids:

Class polychaetes (live in water, predators, development with alternating generations)

Class oligochaetes (

Where live? In water and on land

Dimensions? Up to 49 cm

At what depth do they winter? At a depth of 5-6 m or more.

What is diapause? (worms crawl to depth, curl up into a ball, form a protective capsule)

The earthworm is an oligochaete.

Laboratory work No. 1

"Study of the structure of annelids"

Purpose of the work: to study the structure of the earthworm.

Equipment and materials: Petri dish, wet filter paper, magnifying glass.

Progress

Consider appearance earthworm.

(Body shape -smooth, slippery, cylindrical in shape and consists of piece rings - segments)

Coloring - The earthworm is reddish-brown in color, its ventral side being slightly lighter than the rest of the body.

Dimensions: Adult earthworms are 15–30 cm in length)

Find the head, belt, rings, anus.

Label the parts of the worm in the picture

The parapodia (bristles) of the earthworm perform this movement function.

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 body of the earthworm has a streamlined shape, round in cross section and devoid of any outgrowths , the presence of which could interfere with the free movement of the worm in the soil.

Match the part of the worm with the function it performs.

1. Parapodia (bristles) of an earthworm perform the following function:

A) food capture

B) blood circulation

B) ensuring movement

2. The earthworm belt performs the following functions:

A) food capture

B) excretory

B) takes part in reproduction

3. All representatives of the annelid type are characterized by the following features:

A) unicellularity

B) dividing the body into segments

B) lack of a circulatory system

Conclusion: about how the shape of a worm’s body helps it move.

Leech class

How many segments does the leech class have? 33

Why are suction cups needed? Attached to the victim's body.

Where live? Mainly in fresh water bodies.

Anabiosis? Basic life processes are slowed down.

Gerudin? A special substance that prevents blood clotting.

Questions for consolidation

1. In soils rich in humus lives one of the representatives of the class of annelids - the earthworm. 2. It belongs to the type of oligochaete worms. 3. The earthworm feeds on plant litter, swallowing it along with the soil. 4. Their circulatory system is not closed. 5. Earthworms are hermaphrodites. 6. Their development is direct.

C 2 No. 11011. Find errors in the given text. Indicate the numbers of the sentences in which errors were made and correct them.

1. Annelids are the most highly organized animals among other types of worms.

2. Annelids have an open-ended circulatory system.

3. The body of annelids consists of identical segments.

4. Annelids have no body cavity.

5. The nervous system of annelids is represented by the peripharyngeal nerve ring and the dorsal nerve cord.

Explanation.

1) 2 - annelids have a closed circulatory system;

2) 4 - annelids have a body cavity;

3) 5 - the nerve chain is located on the ventral side of the body.

Homework: Paragraph 10, paraphrase

Earthworms are smooth-walled worms with a body made up 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 largest worms in the soil. IN North America the worms themselves long length 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 anywhere there is moist 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 are they eating?
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 chemical substances. 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).
mites (feed on eggs).
What role do they play in the ecosystem?
Earthworms are very important for the soil. They carry organic material down into more low levels They rid the soil of dead plant material, and their burrows help air and water penetrate 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 the 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.