We call them worms correctly. Participation of worms in the formation of rocks

John Shoch and Jon Hupp in 1978. The term "worm" was influenced by the science fiction novels When HARLEY Turned One by David Gerrold (1972), which described worm-like programs, and On Shockwave. (English) John Brunner (1975), where the term itself is introduced.

One of the most famous computer worms is the Morris Worm, written in 1988 by Robert Morris Jr., who was a student at Cornell University at the time. The spread of the worm began on November 2, after which the worm quickly infected approximately 6,200 computers (this is about 10% of all computers connected to the Internet at that time).

Distribution Mechanisms

All mechanisms (“attack vectors”) of worm propagation are divided into two large groups:

• Exploitation of vulnerabilities and administrative errors in software installed on the computer. The Morris worm exploited software vulnerabilities known at that time, namely in the sendmail mail server, the finger service, and guessed a password using a dictionary. Such worms are able to spread autonomously, selecting and attacking computers in a fully automatic mode.
• Using the means of so-called social engineering, the launch of malware by the user himself. To convince the user that a file is safe, flaws in the program's user interface can be used - for example, the VBS.LoveLetter worm took advantage of the fact that Outlook Express hides file extensions. This method is widely used in spam mailings, social networks etc.

Sometimes there are worms with a whole range of different propagation vectors, victim selection strategies, and even exploits for different operating systems.

Spread speed

The speed at which a network worm spreads depends on many factors: the network topology, the search algorithm for vulnerable computers, average speed creating new copies.

Network worms that spread across a network by directly using TCP/IP protocols, that is, from any IP address to any other, are characterized by rapid spread. Provided that each instance of the worm reliably knows the address of a previously uninfected network node, exponential reproduction is possible. For example, if each instance infects one computer per second, the entire IPv4 address space will be filled by the worm in half a minute. A hypothetical worm that would be able to spread at such a speed was given the name "blitzkrieg worm." Researcher N. Weaver from the University of Berkeley examined simple suboptimal algorithms that could allow a worm, reproducing somewhat more slowly, to nevertheless infect the Internet in 15 minutes. This type of worm is called the “Warhol worm” - in honor of Andy Warhol, the author of the saying:

Most email worms are distributed as a single file. They do not need a separate "infection" part, since usually the user-victim using mail client or Internet browser voluntarily downloads and launches the entire worm.

Often, worms, even without any payload, overload and temporarily disable networks simply due to their intensive spread. Typical meaningful payload may involve corrupting files on the victim computer (including changing web pages, the so-called “deface”); it is also possible to organize a botnet from infected computers to carry out network attacks, send spam, or (more recently) mine cryptocurrency.

Methods of protection

Due to the fact that network worms use vulnerabilities in third-party software or operating system However, using signature-based antivirus monitors is not enough to protect against worms. Also, when using methods

As is known, some of the worms are non-fungible, while others are segmented (see Animals). The most highly organized of all types of worms and at the same time the most important and interesting from a paleontological point of view is the Annelida type (annelids). Annelida are segmented worms: their body is elongated, divided into segments. At one end of the body is the oral opening, and at the other is the anal opening. Most representatives of this type live in the sea. Some of them actively move - either swim or crawl along the seabed, burrow into silt and sand; traces and passages of such worms in some cases are found quite often in rocks where there are no other remains of animals or plants. Other representatives of the type annelids lead a sedentary lifestyle. Some of these worms secrete protective calcareous tubes, sometimes more or less wriggling, and sometimes spirally coiled. These worms live in such tubes and are therefore called tubeworms. Only the pipes are preserved in a fossil state. Of the trumpet veins, the two most widespread genera are Spirorbis and Serpula.

Representatives of the genus Spirorbis (Lower Silurian - now) are preserved in the form of small calcareous tubes coiled into a snail-shaped spiral. In this way, spirorbis resemble the shells of some foraminifera or mollusks. Each such spirally coiled tube is attached with its lower side to some foreign object (algae, shell of a larger animal, etc.).
The genus Serpula (Upper Silurian - now) forms irregularly twisting calcareous tubes, which are usually attached to some foreign objects or to each other. Some annelids have a chitinous jaw apparatus in the form of jagged plates. Similar formations They are also found in fossil form starting from the Lower Paleozoic. They were given a name scolecodonts. This word means "teeth of worms"; Paleontologists who study them tend to consider scolecodonts to be the remains of ancient annelids. Scolecodonts are typically microscopic in size and vary greatly in shape. These fossils consist mainly of organic matter (about 50%) and silica (about 45%).

Worm burrows, often observed in large numbers in some breeds, deserve special attention. These passages apparently also belong to annelids. The so-called sandworms belonging to this type, eating silt, go deep into the sediment by about 60 cm. According to some calculations, this entire 60 cm layer passes through the intestines of sandworms in approximately two years. Similar mud-eating worms undoubtedly existed in previous geological eras. The passages of such worms sometimes abound in layers of sedimentary rocks that are extremely poor in other remains of organisms. The burrows of worms, often found in the strata of the so-called flysch, have long been described under the name fucoids and were initially mistaken for the remains of algae. Quite often one has to observe, for example, slabs of marl with numerous round exits of tubular worm passages. After carefully removing the top layer of such a slab, you can see the branching of the passages.

Annelids are of great theoretical interest to the evolutionary paleontologist. In their structure they closely resemble the type of arthropods, and, apparently, these latter descend from some ancient Annelida.

Participation of worms in the formation of rocks

Representatives of the genus Serpula and forms close to them are of great importance as rock-forming organisms. The winding tubes of these fossils may form strata rocks. In northwestern Germany, Lower Cretaceous serpulite (i.e. rock formed by serpules), the layer of which reaches a thickness of 50 m, in some places consists entirely of tubes of these fossils. Serpuls take a noticeable part in the formation of some limestones common in Russia (can be seen in the example of the Moscow region) and in the territory. Ukraine (for example, reef limestones of the Middle Miocene of the southwestern part of Ukraine).
The huge role of earthworms (also belonging to the phylum annelids) in the processing and loosening of soil cover and denudation earth's crust became generally known after the work of Charles Darwin “The Formation of the Vegetative Layer of the Earth by the Activity of Earthworms.”

- (Vermes), a collective group of invertebrates, uniting lower bilaterally symmetrical animals (Bilateria) with an elongated body, the swarm was previously given the rank of phylum. Modern Researchers divide Ch. into independent types: flat Ch., nemerteans,... ... Biological encyclopedic dictionary

- (Vermes) extensive gr. invertebrates, characterized by a number of common features: bilateral body structure, the development of a skin-muscular sac that envelops the body and consists of single-layer epithelium and differently structured muscles, the absence of... ... Geological encyclopedia

Worm, worm... Russian word stress

1. WORMS, her; WORTS, worm; pl. (unit of heart, s; g.). Card suit, indicated by red hearts. Lead hearts. Seven of Hearts. Ch. trumps. On hand are one piece ◁ Hearts; Chervonny, oh, oh. Ch. ace, king. 2. WORMS see Worm. * * * worms... ... Encyclopedic Dictionary

Hearts, hearts, suit, worms, worm Dictionary of Russian synonyms. worms noun, number of synonyms: 6 fats (5) suit... Dictionary of synonyms

WORMS- (vermes), a type (and according to some authors a group of types) of invertebrate animals, occupying, in terms of the height of their organization, a kind of middle position between coelenterates, on the one hand, and arthropods (and soft-bodied animals) on the other. Ch. have b. h... ... Great Medical Encyclopedia

worms- WORMS, worms, unraveled. reduction heart... Dictionary-thesaurus of synonyms of Russian speech

WORMS, a collective group of invertebrate animals. Most worms have an elongated body, the walls of which consist of skin and muscles. About 40 thousand species. Free-living forms live in seas, fresh waters and soil. Besides,… … Modern encyclopedia

A collective group of protostomed invertebrate animals with an elongated body, uniting flatworms, protocavity worms, netelminthes, nemerteans, annelids, etc. Big Encyclopedic Dictionary

WORMS, worms. see hearts. Dictionary Ushakova. D.N. Ushakov. 1935 1940 ... Ushakov's Explanatory Dictionary

WORMS, ey, yam and WORMS, worm, worms. IN playing cards: The name of the red suit with hearts. King of Hearts. | adj. red, aya, oh and hearts, aya, oh (colloquial). Queen of Hearts. Ozhegov's explanatory dictionary. S.I. Ozhegov, N.Yu. Shvedova... ... Ozhegov's Explanatory Dictionary

Books

• Worms, R. Flanagan. 1995 edition. The condition is very good. A country of many millions, proud of a powerful army, enthusiastically chanting “USA” and an army machine that crushes people under itself. Army and...
• Parasitic worms are the cause of unrecognized diagnoses, O. I. Eliseeva. What is helminthiasis, what types of parasites can inhabit our organs, and what are the known ways of their penetration into the human body. Symptoms of helminthiasis and its similarity to...

The types of worms bred on verifer farms are diverse and they belong to invertebrates. In turn, if you are interested in what kind of worms there are, then you need to know that representatives of this family have a classification and numerous varieties, but they all have an oblong body, as well as a front and rear end. The body of the worm is enclosed in a skin-muscular sac.

Types

The type of worms can be the following:

• flat;
• ciliary;
• tape;
• round;
• ringed

The characteristics of worms include their structure and size, which can be different. The body of the bulk of worms is elongated, has a thread-like shape and is slightly flattened, if we talk about a flatworm or tapeworm. If we take the round and ringed one, then its body is cylindrical in cross-section, similar to a circle.

Body size roundworms can be quite small and can only be seen well with a microscope, but there are also species that are impressive in size, one or two meters in length and even more.

Flat

Flatworms have, as their name suggests, a flat (even flattened), symmetrical body on both sides; the head and tail are clearly defined. Representatives of this species do not have respiratory organs and blood vessels. The exchange of gases occurs throughout the body. The musculocutaneous pouch consists of epithelium and 2 layers of muscle - circular and longitudinal.

Speaking briefly about the nervous system of flatworms, it is worth noting that in almost all species it is composed of longitudinal columns (dorsal, abdominal and lateral). Some species have cells of touch, as well as organs that help the worm navigate and distinguish between chemicals. compound environment, which allows them to navigate quite confidently.

Most flatworms are hermaphrodites. This means that they have both male and female cells. However, they cannot fertilize themselves. When mating, two individuals tightly touch each other with their abdominal parts and sperm are exchanged. As a result, each individual will independently lay eggs.

This video tells everything about the life activity and structure of a flatworm

Ciliated worms are distinguished by their oval shape - the surface of the body is covered with ciliated epithelium. With the help of these cilia, the worm communicates with the outside world. They live in both salty and fresh water, individual species on land. In the front part of the body of ciliated worms there are organs of touch and a mouth on the abdomen.

The musculocutaneous pouch contains circular, longitudinal and diagonal muscles. The skin contains glands that secrete mucus, which is necessary for the worm to glide. In some species it is toxic and with the help of them it can kill prey.

Curious!!! The ciliated worm has pharyngeal glands that secrete an enzyme necessary for digestion. The worm can attack various small crustaceans, which it is unable to swallow. In such a situation, he injects this enzyme into the victim, and then eats the half-digested mass.

Reproduction of this species occurs similarly to flat ones.

The size of tapeworms can be either completely microscopic or quite impressive, up to ten meters. The body of the tapeworm is divided into segments. In the front part is the head, which has microscopic suckers; in front of it is the neck, which is constantly turning into new segments. It is through this process that the worm grows. All segments contain reproductive organs. Worms of this species are cross-fertilized and eggs mature in all segments.

The roundworm has a long body shape that is circular in cross section. The mouth is located in the front of the body. The intestinal tract is straight. The back part ends with an opening through which the intestinal tract is emptied. The body is covered with a specific cuticle. Between it and the intestinal tract there are longitudinal muscles and 4 chords, which have different purposes. The dorsal and abdominal ones provide nerve trunks, and the lateral ones contain the sensory nervous system and excretory channels.

Curious!!! Growing in the process of life, worms of this species are freed from old skin, replacing it with new one. This type can reproduce without mating. Very often, the appearance of larvae occurs in the body of the worms themselves.

Ringed

Ringed animals are considered the most organized of all species. Its body is made up of single segments. This species does not shed its cuticle during its life, which increases as its body grows. Their body is covered with chitinous bristles, which are its limbs. The movement of individuals of this species occurs due to muscle contraction or with the help of bristles.

Under the skin there are longitudinal and circular muscles. The body of worms of this species contains a specific liquid. The intestinal tract is straight, the digestive tract has a through structure.

Curious!!! In individuals of this species, the blood supply system is closed and includes a pair of vessels, one of which is located on the back and the other on the abdomen. Blood, depending on the type, can be different colors from red to colorless.

If we talk about the nervous system, it is quite primitive and consists of two nodes, the head and the abdominal. All segments of the body of worms of this species have their own nerve ganglion. Some species have eyes on the head, while others have tactile cells on the body. They can reproduce without pairs.

This video shows what types of annelids there are and everything about their structure and life activity.

Annelids have the highest organization compared to other types of worms; they develop a secondary body cavity for the first time, circulatory system, more highly organized nervous system. In annelids, inside the primary cavity, another, secondary cavity has formed with its own elastic walls made of mesoderm cells. It can be compared to airbags, one pair in each segment of the body. They “swell”, fill the space between the organs and support them. Now each segment received its own support from the bags of the secondary cavity filled with liquid, and the primary cavity lost this function.

They live in soil, fresh and sea water.

External structure

The earthworm has an almost round body in cross section, up to 30 cm long; have 100-180 segments, or segments. In the anterior third of the body there is a thickening - the girdle (its cells function during the period of sexual reproduction and egg laying). On the sides of each segment there are two pairs of short elastic setae, which help the animal when moving in the soil. The body is reddish-brown in color, lighter on the flat ventral side and darker on the convex dorsal side.

Internal structure

Characteristic feature internal structure is that earthworms have developed real tissues. The outside of the body is covered with a layer of ectoderm, the cells of which form the integumentary tissue. The skin epithelium is rich in mucous glandular cells.

Muscles

Under the cells of the skin epithelium there is a well-developed muscle, consisting of a layer of circular muscles and a more powerful layer of longitudinal muscles located under it. Powerful longitudinal and circular muscles change the shape of each segment separately.

The earthworm alternately compresses and lengthens them, then expands and shortens them. Wave-like contractions of the body allow not only crawling through the burrow, but also pushing the soil apart, expanding the movement.

Digestive system

The digestive system begins at the front end of the body with the mouth opening, from which food enters sequentially into the pharynx and esophagus (in earthworms, three pairs of calcareous glands flow into it, the lime coming from them into the esophagus serves to neutralize the acids of rotting leaves on which the animals feed). Then the food passes into the enlarged crop and a small muscular stomach (the muscles in its walls help grind the food).

The midgut stretches from the stomach almost to the posterior end of the body, in which, under the action of enzymes, food is digested and absorbed. Undigested remains enter the short hindgut and are thrown out through the anus. Earthworms They feed on half-rotten remains of plants, which they swallow along with the soil. When passing through the intestines, the soil mixes well with organic substances. Earthworm excrement contains five times more nitrogen, seven times more phosphorus and eleven times more potassium than regular soil.

Circulatory system

The circulatory system is closed and consists of blood vessels. The dorsal vessel stretches along the entire body above the intestines, and below it is the abdominal vessel.

In each segment they are united by a ring vessel. In the anterior segments, some annular vessels are thickened, their walls contract and pulsate rhythmically, thanks to which blood is driven from the dorsal vessel to the abdominal one.

The red color of blood is due to the presence of hemoglobin in the plasma. It plays the same role as in humans - nutrients dissolved in the blood and spread throughout the body.

Breath

Most annelids, including earthworms, are characterized by cutaneous respiration; almost all gas exchange is provided by the surface of the body, so the worms are very sensitive to wet soil and are not found in dry sandy soils, where their skin soon dries out, and after rains, when there is a lot of water in the soil, they crawl to the surface.

Nervous system

In the anterior segment of the worm there is a peripharyngeal ring - the largest cluster nerve cells. The abdominal nerve cord with nodes of nerve cells in each segment begins with it.

This nodular type nervous system was formed by the fusion of nerve cords on the right and left sides of the body. It ensures the independence of the joints and the coordinated functioning of all organs.

Excretory organs

The excretory organs look like thin, loop-shaped, curved tubes, which open at one end into the body cavity and at the other outside. New, simpler funnel-shaped excretory organs - metanephridia excrete harmful substances in external environment as they accumulate.

Reproduction and development

Reproduction occurs only sexually. Earthworms are hermaphrodites. Reproductive system they are located in several segments of the front part. The testes lie in front of the ovaries. When mating, the sperm of each of the two worms is transferred to the seminal receptacles (special cavities) of the other. Cross fertilization of worms.

During copulation (mating) and egg laying, girdle cells on the 32-37 segment secrete mucus, which serves to form an egg cocoon, and a protein liquid for nutrition developing embryo. The secretions of the girdle form a kind of mucous coupling (1).

The worm crawls out of it with its back end first, laying eggs in the mucus. The edges of the coupling stick together and a cocoon is formed, which remains in the earthen hole (2). Embryonic development of eggs occurs in a cocoon, from which young worms emerge (3).

Sense organs

The sense organs are very poorly developed. U earthworm there are no real organs of vision; their role is played by individual light-sensitive cells located in skin. The receptors for touch, taste, and smell are also located there. Earthworms are capable of regeneration (easily restore the back part).

Germ layers

The germ layers are the basis of all organs. Annelids have ectoderm (outer layer of cells), endoderm (inner layer of cells) and mesoderm ( intermediate layer cells) appear at the beginning of development as three germ layers. They give rise to all major organ systems, including the secondary cavity and the circulatory system.

These same organ systems are subsequently preserved in all higher animals, and they are formed from the same three germ layers. This is how higher animals repeat in their development evolutionary development ancestors