Earthworm color, body shape and size. Earthworms Life cycle of earthworms
The earthworm family consists of almost 170 species and belongs to the phylum 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. EARTHWORM
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, such as damp soil, wet moss, and near water bodies. 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 varies - 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 of various 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.
Earthworms are one of the most ancient inhabitants of planet Earth. They live almost everywhere, with the exception of the permafrost of Antarctica. Thanks to this boneless creature, the soil becomes fertile. It is their vital activity that is the fundamental factor for the formation of the fertile layer.
General characteristics and living conditions
The earthworm's body shape, color, and size are the unique characteristics of an invertebrate. Let's take a closer look.
The body of the worm is made up of many ring-shaped segments. In some individuals their number reaches 320. The worms move with the help of short bristles located on these segments. Externally, the body of individuals resembles a long tube.
For their normal functioning, the humidity level must be at 75%. Worms die if the soil dries out and the humidity drops to 35% or lower. This is due to the fact that they breathe through their skin. Consequently, they simply cannot live in dry soil and water.
The most optimal temperature for their comfortable life is from 18 to 24 degrees above zero. If it starts to get colder, the worms begin to go deeper, where it is warmer and more humid. If the atmospheric temperature does not rise, they hibernate. If this indicator rises above 42 degrees, then the worms die. The same thing happens if the temperature is too low. And worms crawl out after rain due to lack of oxygen in the soil.
Interesting fact: it was the ability to fall into a state of suspended animation that allowed worms to survive during the Ice Age.
The benefits of worms
It is thanks to worms that the soil throughout the planet is in constant motion. The lower layers rise to the top and are saturated with carbon dioxide and humic acids. These invertebrates provide potassium and phosphorus.
Worms prepare the soil for plant growth better than any human hand or technique. Thanks to these creatures, even large stones and objects sink deep into the ground over time. And small pebbles are gradually ground in the stomach of the worms and turn into sand. However, the excessive use of chemicals by humans in agriculture inevitably leads to a reduction in their population. Today, there are already 11 species of earthworms in the Red Book of Russia.
Color
The color of an earthworm directly depends on skin pigments. But this characteristic is relevant only for living individuals.
If the worm lacks skin pigments, it will remain pink or red throughout its life. In the presence of this component, the color of the earthworm can be brown, blue, yellow or brown.
For example, the Allophora chlorotica worm is yellowish or greenish in color. A Lumbricus rubellus - earthworms are brown-red or purple in color with a pearlescent tint.
Body length
The average size of all individuals is from 5 to 20 centimeters, with a thickness from 2 to 12 mm. However, in tropical forests there are invertebrate individuals up to 3 meters long. Naturally, with such sizes there can be more than 3 thousand ring-shaped segments.
Types of worms
Invertebrate animals live in all layers of the soil, hence the species that feed on the surface of the earth are distinguished:
Surface Feeders | Soil feeders |
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Litter | Individuals under no circumstances fall below 10 centimeters into the ground | Living in deep soil layers |
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Soil-litter | They live at a depth of 10 to 20 centimeters | They constantly form new tunnels, but feed in the humus layer |
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They constantly make deep passages, but only the upper end of the body can come out for food consumption and mating. |
Littering and burrowing individuals are characteristic of waterlogged soils. In other words, they live near ponds, swamps and in regions with a humid subtropical climate.
The tundra is characterized by soil-litter and litter worms. In the steppes, only soil species can be found.
Worm nutrition and digestive organs
Regardless of the type and color of the earthworm, they are all omnivores. By ingesting huge amounts of soil, they consume half-rotten leaves. From this mixture they receive useful substances. They do not eat only leaves with an unpleasant odor, but they like fresh leaves.
Charles Darwin wrote about the omnivorous nature of worms. He conducted many experiments by hanging pieces of various foods, including the remains of dead worms, over a pot containing animals, and most of this food was eaten.
After digesting the soil, the worm rises out and throws it out. Excreta, soaked in intestinal secretions, is viscous and hardens when dried in air. There is no randomness in their actions; waste is first dumped on one side, then on the other. As a result, a characteristic turret-like entrance to the burrow is formed.
Worms not only feed on leaves, plant stems, and scraps of wool, they use them to plug the entrances to burrows.
In all earthworms, regardless of body shape and color, the mouth is located at the front end of the body. The swallowing process occurs due to the muscular pharynx. After this, food - earth with leaves - enters the intestines. If some part of the food has not been digested, it is thrown away along with the processed food. The release occurs through the anus, located at the posterior end of the body.
Reproductive system
All earthworms are hermaphrodites. Before laying eggs, two different individuals exchange seminal fluid by lightly touching them. After this, each worm secretes mucus from a “belt” located on the front of the body, into which eggs enter. After some time, the lump with them practically slides off the body and turns into a cocoon. After maturation, young individuals emerge from it.
and sense organs
Absolutely all individuals, regardless of the color of the earthworm, do not have sense organs. Their tactile sense works best. Similar cells are located throughout the body, and even a slight vibration of the ground causes the worm to hide and sink into deeper layers of soil. These elements are also responsible for the perception of light. After all, such individuals do not have eyes. But if you shine a flashlight on them at night, they will quickly hide.
Researchers say worms have a nervous system. This is confirmed by the fact that they have elementary reflexes: when the body is touched, it instantly contracts, protecting the worm from touch.
Even Darwin noticed that such creatures are distinguished by their smell. If the worm does not like the aroma of food, then he will refuse such a meal.
Animal enemies
It doesn’t matter at all what body color an earthworm has, what type it is or where it lives, all individuals have natural enemies. The most terrible of them is the mole. This mammal not only eats worms, but also stores them for the future. The mole has a paralyzing substance in its saliva that acts specifically on invertebrates. This is how he catches worms.
Frogs and shrews will not disdain to taste them. Many birds eat earthworms - these are blackbirds, poultry, starlings and woodcocks. Many arthropods do not disdain worms - these are arachnids, various types of insects and centipedes.
Vermiculture
Recently, the topic of organic vegetable growing has become relevant. The question may arise as to what worms have to do with it. Everything is very simple. Vermiculture is based on the cultivation of earthworms. In this case, it does not matter at all what color the earthworm is, the most important thing is the production of vermicompost. Recent trends suggest that vermiculture will soon completely replace harmful chemical fertilizers from agriculture.
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 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 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 internal organs to work more fully. 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 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. 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.
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 the appearance of the 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 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, retelling
After much scientific research and zoological work, it was possible to determine an interesting fact: the ordinary earthworm plays a very important role in the decomposition of organic substances that fall into the soil, enriching it with humus and other important plant nutrition elements rising from the deep layers of the root system.
These are the animals occupy a leading position along with the most important soil helpers, and a worthy alternative for the earthworm has not yet been found. If there are colonies of these eukaryotes in the soil, fertility indicators will be maximum, since they directly depend on the volume of organic substances that enter the soil.
It is very difficult to overestimate the role of the earthworm for the ecosystem. Such a tiny creature enriches the soil with all useful elements, making it fertile and healthy. Few people know about this, but the life and existence of the human race is strongly connected with the activities of these animals. Their disappearance would have fatal consequences, including mass deaths due to starvation.
Earthworm: main characteristics
An earthworm or earthworm is a segmented worm with a tubular shape. The animal is found on all continents of the globe, in places with an abundant supply of moisture and organic matter. Life expectancy reaches 4-8 years and is determined by the type of specific inhabitants. Some of them can live up to ten years. An interesting structural feature is the digestive system, which runs along the entire length of the body. In this case, food is digested by moving a set of muscles.
Small earthworm has a central and peripheral nervous system. He can also breathe through his skin. This creature's body is filled with slimy fluid and acts as a hydrostatic skeleton. Any cartilage and connective tissue are absent. The presence of circular and longitudinal muscles allows the animal to move normally from one place to another.
It is important to note that due to the unique body structure of the earthworm, it is often called the most mysterious creature on the planet. He lacks eyes, ears and even lungs. But the animal has several hearts. At the same time, the mucous liquid has an unpleasant taste, so predators do not consume it as food.
Varieties of earthworm
Group of earthworms consists of many subspecies and families. Currently, more than two thousand species can be identified that are found in all regions of our globe. 40 of them live on the European continent. The most popular are two main types: the common earthworm and the dung worm. Let's look at the detailed characteristics of both varieties.
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Earthworms may vary and biological properties, such as type of nutrition and habitat in the soil. For this reason, scientists distinguish two main varieties:
- worms that live on the surface of the soil;
- worms that dig deep holes and make homes inside the soil.
Life cycle of earthworms
If we highlight the main features of the life cycle of an earthworm, they will be divided into four stages:
![](https://i2.wp.com/zveri.guru/images/258326/cherv.jpg)
As mentioned above, the role of worms in nature is colossal. For this reason, these animals are now being bred and popularized to improve the fertility of vegetable gardens. The abundance of such invertebrates in the soil leads to the successful cultivation of various plant crops. Also worms are important for gardeners, which is why they are often called “the first agricultural technicians.” And this is explained by a simple fact: the more worms in the soil, the better the garden trees will develop.
But what is the impact of such creatures on the ground? First of all, they solve a lot of problems of loosening the soil, improving its structure and increasing fertility. As a result, the gardener is relieved of a lot of additional worries.
In addition, as animals move through the garden, they dig deep tunnels that ensure a stable flow of air through the seeds and roots of plants. This behavior allows us to call worms invisible tiny plowmen. It is also important to note that invertebrates protect vegetation from numerous diseases and pests. They produce stable humus by eating organic matter, including rotten leaves, dirt and grass clippings.
During the digestion of food the worm excretes a large amount of organic excrement, which contains elements such as:
- phosphorus;
- calcium;
- nitrogen;
- magnesium.
Therefore, if you come across a colony of earthworms in your garden or vegetable garden, the question “is this inhabitant useful for the local ecosystem” should automatically disappear.
Interesting fact: The famous scientist Charles Darwin, who proposed the theory of natural selection, paid great attention to the study of the life cycle of earthworms. Over the course of 40 years of his life, he conducted various experiments and studies with these spineless creatures, as a result of which a book was born entitled “The formation of the vegetable layer of the earth by the activity of earthworms and observations on their way of life.”
How to increase the earthworm content in the garden. Home breeding
There are many ways to improve soil fertility in a vegetable garden or garden by promoting invertebrates. Experienced gardeners use various organic substances for this purpose. Periodic mulching of the soil also helps. Humus, fallen leaves, manure, compost and other similar materials are placed on the surface layer of soil.
In addition, many gardeners breed worms at home. It is important to note that such an activity does not require any special effort or investment. It is enough to provide optimal access to food, proper humidity, darkness and free space. Successful organization of a worm house can be carried out in the spring or early summer, since during this period the temperature range remains optimal. The worms will have time to multiply and become strong before the onset of winter. So, now directly about breeding worms in the garden.
The worm house is a special structure in which representatives of the spineless will live and develop. You can use absolutely any container - boxes, troughs, old bathtub, etc. For successful cultivation, it is recommended to carry out the procedure on open compost. But it is important to protect the selected area with a special net to prevent massive consumption of worms by birds and other animals.
In order for the care and maintenance of these little plowmen to be as effective as possible, you need to put compost on the bottom of the future house (the optimal layer is 40 centimeters thick) and thoroughly treat it with warm liquid. After this, you need to arrange a straw bedding and wait 5-6 days for complete absorption. That's all, the home can be considered ready to move in.
Finding earthworms for your upcoming stocking is easy. To do this, it is enough to dig up a small layer of soil in your own garden or garden. Individuals that appear on the top layer of soil after heavy rain take root particularly well. You can also buy worms at the appropriate store.
The settlement process can be divided into several stages. First you need to dig a small hole in the center of your home and throw a bucket of worms there. After this, they can be covered on top with straw or burlap. The first results of successful settlement will be noticeable within seven days. You need to periodically monitor the creatures and their behavior in their new habitat. If animals lead an active lifestyle, it means they have settled in well and everything is fine with them.
In order for the little ones to quickly adapt to new conditions, start feeding them only 3-4 weeks after moving in. But warm water needs to be added to the worm trap at least 2 times a week.
Earthworm Care
When asking the question “how long do earthworms live,” it is important to pay attention to the correct care and the conditions created. In order for animals to develop normally and fulfill their reproductive duties, they need to be provided with relative coolness, shade and a balanced food supply. Experienced experts advise adding a small amount of sand or crushed eggshells to compost manure. Once every 14 days it is necessary to add food to the ground. But under no circumstances should you overfeed animals.
If you are going to breed worms at home, you should know that these creatures are capable of processing almost any organic product. The main thing is that they are crushed, since animals do not have teeth.
It should be noted that before replenishing the worm cage with fresh food, you must make sure that the previous supply is completely eaten. Otherwise, the spineless ones will become oversaturated and soon die. If organic compounds remain in the compost, acidity levels can skyrocket, creating lethal conditions in the soil. Also, excess feed leads to the proliferation of dangerous pests, including mites.