Biological significance of annelids. The variety of annelids, their common features
General signs of annelids
annelids - multicellular, binary-symmetric, three-layered animals that have a secondary body cavity. The kilchak type unites more than 9000 species (in Ukraine - about 450 species). They live in sea and fresh waters, as well as in the soil compared to representatives of other types of worms, kilchaks have a significantly higher level of organization. The progressive features of the organization of annelids are: 1 ) the appearance of a secondary body cavity 2) division of the body into separate segments (metamerism) ; 3 ) appearance of primitive limbs (parapodia in polychaete worms) ; 4 ) appearance of the circulatory and respiratory systems (external gills in polychaete worms) ; 5 ) development of metanephridia.
Black Sea, Azov and Mediterranean Sea, Atlantic Ocean, Pacific Ocean, Indian and frozen North. Heavy branched bran with a thin terminal thread, brown to carmine. At an altitude of 1.5 to 3 m above sea level. It lives on the temperate Atlantic coast of the Atlantic. The dichotomous fragment is branched; branches start at the base and are placed on a cross or spiral. In all major European conditions. He prefers organic and clear aqueous solutions.
It develops best in calm areas. On the Black Sea, the Mediterranean Sea, on the European coast of the Atlantic Ocean, in the Indian Ocean. Perennial, rhizome torrent, inflorescence with unisexual flowers, protected by the back. On the seashore and coastal lakes, it is food for fish and water birds. Dry, it is used for mattresses or packaging.
structural features
Body into kilchak into multicellular, formed by many segments. The repeated repetition of body segments is called metamerism. This principle of body organization arises in the process of evolution in connection with the elongation of the body. Segments - parts of the body that are similar in structure, arranged in series one after the other. The segments outside and inside are the same, therefore, in kilchakiv homonomous metamerism, or segmentation, of the body. Many representatives have bristles on the body segments. The body consists of the head end, trunk and anal lobe. Such a clear division of the body into sections is observed in kilchakiv for the first time.
Perennial, thin rhizomes, branched, with stems and linear leaves. Raw, it is consumed by pigs. Black, Caspian, Mediterranean and Baltic. Perennial, thick rhizomes, long roots, shrubs with linear leaves and half-breed flowers. In dry places, sunbathing, on the sand of the sea.
Frequency in the delta beyond Tuzla appears elsewhere in the south of the country through steppe and sandy pastures. The smell of leaves, sects, with filamentous lecites. On the ribs of Loesso, on the seashore, but also in other parts of the country. Southeast Europe, Asia Minor, Caucasus.
covers are represented by a well-developed musculocutaneous sac, which includes: dense thin cuticle , hypodermis And two layers of muscles(ring and longitudinal). The skin has many mucous glands.
body cavity secondary (in general) segmented. It differs from the primary cavity in the presence of its own epithelial lining, which, on the one hand, is adjacent to the walls of the sac, and on the other, to the walls of the digestive tube. The leaves of the lining grow together above and below the tube, forming a mesentery, which divides the coelom into right and left parts. Transverse partitions divide the body cavity into chambers, the number of which corresponds to the number of segments. The whole is filled with a liquid, which is very similar in chemical composition to sea water. The coelomic fluid is in constant motion and performs a number of important functions: washing the organs of the body, supplying them with nutrients and oxygen together with blood, helping to remove CO2 and metabolic products, moving biologically active substances and phagocytes, etc.
On the sand, by the sea. Around Europe, North Africa and Southwest Asia. Perennial, turning root, branched, very branched stem, bare leaves. On the coast, along the coast, in southern and western Europe. Perennial with a long rhizome and a lying stem, branched, branched. Only on coastal sands, on the Danube Delta and on the Black Sea coast, the Mediterranean, Crimea, Transcaucasia and Syria.
Globe bush, different sects, leaves around the edges. On the sands of the Black, Caspian, Northern Baltic, Mediterranean and Atlantic Ocean. The root is used in heartbeat. All parts of the air evaporate. The leaves are of various shapes, depending on the height at which they are on the stem.
life features
Support connected with hydroskeleton, functioning thanks to the coelomic fluid.
Motion muscular. In polychaete worms there are muscle growth segments of the body - parapodia, that form the propulsion system. In oligochaetes, in their place are tufts of setae.
On loess-like, sandy or rocky ground, from Constanta to Mangalia. The leaves are covered with harsh pearls. In the bushes, on the shores of the sea, south of Tuzla, but also along the edges of the roads, alive. South and Western Europe, Asia Minor and Iran. Frunze is located on a rosette at the base of the stem. On depressions, on salty ribs, on all the beaches of the Romanian coast.
In southeastern Europe and western Siberia. Perennial, velvety-wiggy, thick, ovate leaves. Loyal, bare, vigorous, alternate leaves, cecilla, lanceolate. On rugged, arid, stony or stony ridges, south of Constanta, but also in other areas in the south of the country.
Digestion It is provided by a differentiated digestive system, which has three sections: anterior (mouth, pharynx, esophagus with an ax, stomach with muscular walls), middle (middle intestine) and posterior (hind intestine with anus). Each section of the system performs its own specific function. For example, in the wall of the midgut there are cells that secrete digestive enzymes and cells that digest food, so the main function of this section is the digestion and absorption of food.
Hairy, fleshy, lanceolate, thick, triangular, serrated, hairy leaves. Grass recommended for hydropos. On the loess-like banks of the littoral, south of Constanta. Branched stem with linear, lanceolate, white, hairy leaves. A commune in the southern part of the country, often on the loess-like shores of the sea.
Branched stem with spiny leaves. With diuretic properties, used as teas to treat liver failure and chronic eczema. On sandy or clay soils, on the coast or on a lake. The rhizome is horizontal, rigid, cylindrical aerial stems. The leaves separate from the base of the stem, a cylindrical, stiff, long limb. On wet sands and in swamps lying on the seashore, on some coastal lakes. Europe, West Asia, North Africa, America, Australia.
Transportation of substances in kilchakiv is already being carried out with the participation circulatory system, which appears for the first time. In annelids closed circulatory system a system in which blood moves only through the vessels and does not enter the body cavity. Their circulatory system is formed by the dorsal and abdominal blood vessels, interconnected by annular vessels. Small capillaries depart from these vessels, which, branching out, form a dense network in the skin and internal organs. The movement of blood is due to the pulsation of the annular vessels, they do not have a heart. The blood may be colorless or colored due to the presence of respiratory pigments: chlorocruorin (determines the green color of the blood), hemoglobin and hemoerythrin (cause the red color).
On coastal and continental sands. Central and Northern Europe, around the Black Sea and the Caspian Sea. A sponge with a horn-shaped, irregular shape, similar to branches that are woven. Ash, yellowish, brown or reddish, with a smooth body surface. Filter through the fine organic water that feeds it.
In all seas and northern hemispheres. Ventral mouth surrounded by four long arms, with many projections. Most often in cold waters. Feeds fish and crustaceans. Unwanted fishermen, in winter, penetrate their nets. Very common in the Black Sea. In all worlds and oceans of the globe.
Breath already carried out with the participation respiratory system, which appears for the first time. its appearance is associated with an intensive metabolism in comparison with the previous groups of invertebrates. In some marine kilchaks, organs of water respiration arise - gills, which are thin-walled formations with an extensive network of vessels, which are located on the Parapodia, head and tail. But in most kilchaks, gas exchange is carried out through the covers.
Ventral mouth, surrounded by 8 very spatulate arms in the middle and bifurcated towards the ends. It feeds on juvenile fish and small crustaceans. On the Black Sea coast, it comes ashore when the sea water is warm. In all seas and oceans, frequent in the Mediterranean basin. The soft body is fixed on the support with a disk acting as a suction cup. The tentacles recede abruptly when they touch, the animal enslaved like a fleshy flask. Predator, capturing crustaceans, worms and fish sticks touching tentacles. Avoid direct light on rocky fountains.
On the Atlantic Ocean and the great Mediterranean and Black. The body is like an egg with stripes of cilia, thanks to which it slowly moves along the plankton; with two long tentacles to catch food. He is the only reader in the Black Sea. Common in the sandy moss of sea salt waters and salt lacustrine lakes, in the hills of Zoster. He also digs up galleys, which he licks with goo.
Selection takes place with excretory system formed by special bodies - metanephridia. These organs begin in the body cavity as a funnel, from which a canal extends, opening outward in another segment. Each segment contains a pair of such excretory organs.
Regulation processes carried out by the nervous nodal system of the chain type. CNS formed supraesophageal and subpharyngeal nerve ganglions, supraglottic bridges and abdominal nerve cord. The PNS is represented by nerve branches.
In all large and round European borders. On the sea, seaside lakes, stones, woods, shells, reeds, hulls. Rigid, very resistant tile. In the seaside area, on the upper border of the waves, in very good oxygen-containing waters. Commune in all major and oceanic circulation. In all large and oceanic turnover.
It lives at 4-15 m above sea level, on algae rocks, or on Soest leaves. Species characteristic of the Black Sea. Transparent glass shell. Common in shell shells on beaches. Throughout the Mediterranean basin, including the Black Sea. Thin, glossy, transparent, variable shape.
Irritability provide well developed organs feelings. In the integument, cells that distinguish between tastes and smells are sensitive, the organs of touch are the antennae, bristles, the existing organs of vision, and sometimes the organs of balance.
reproduction mainly sexual with the participation of the reproductive system. Polychaete worms are dioecious, while oligochaetes and leeches are hermaphrodites. Fertilization can be both external and internal. In aquatic annelids, asexual reproduction is also found, in which their body can break up into several unequal parts (disordered division) or into separate segments (multiple fragmentation).
Along our coast, in the sweetest areas, at an altitude of 7 to 50 m above the mouth of the Danube, in Razelm, in gracious and sandy mossy pools. East Atlantic and southern Europe. It lives on various algae, in Zoster and Fillofor, at an altitude of 30 m above sea level, together with Rissa. Appears on shell shells on beaches.
In the Atlantic Ocean and in southern European countries. On sandy and sandy pools, on various algae and Zoster a, at an altitude of more than 1.5 m above sea level. Throughout the Mediterranean basin, the Black Sea and Azov as an excellent variety. Dorsal brown face, ventral white side. In dairy or sandy areas - from 80 to 80 meters.
Development in oligochaetes and leeches - straight. In polychaetes - indirect, in which a larva is formed trochophores. She swims in the water for some time, then settles to the bottom and turns into an adult organism.
Regeneration well developed in oligochaetes and polychaetes, while this ability is lost in leeches.
In the Atlantic Ocean and the Mediterranean basin. Large, hard shell, brown, brown-closed. On a large number in the shell on the beaches. The new immigrant on the Black Sea has no enemies. Communes in the Sea of Japan, the Indian and Atlantic Oceans, throughout the Mediterranean basin. It forms huge compact agglomerations on rigid sublayers, between 0-60 m, where oysters reach each other along the baysus strings, forming a special biocenosis - mitoloid facies. She does not live in association with oysters.
In the eastern part of the Atlantic Ocean and the Mediterranean basin. Surface of straight peristaltic valves. On the merciful beaches, located at an altitude of more than 50 m above sea level, forming a "phasoline mason", which is the last living belt above the azoic region of the Black Sea, it is a favorite product of Bentophage fish, especially sturgeons, in the Mediterranean basin and the Atlantic Ocean. On rocky, merry or sandy beaches forming transitions between 4-50 m above sea level.
Variety of annelids
The type is divided into several classes, including Polychaetes, Low-bristle, Leeches.
polychaete worms, or polychaetes - a class of annelids that have parapodia with numerous setae on each segment of the body. About 5300 species belong to this class, which live mainly in the seas, and only a few representatives have adapted to life in fresh water bodies or wet places on land. They lead a bottom lifestyle (benthic animals), some are free-swimming, there are also sessile forms, they secrete protective tubes around themselves. Mostly predators, but among them there are many herbivorous and omnivorous forms. Among the polychaetes, there are also Commensal species that live inside sponges, in the shells of hermit crabs, or on starfish. The body of polychaete worms consists of a head section, a segmented trunk, and an anal lobe. On the head there are eyes, organs of touch - tentacles, organs of smell - sniffing pits, in some - organs of balance (statocysts). On the trunk segments there are paired lateral outgrowths with bristles - parapodia - primitive limbs with which the worms swim, crawl or burrow into the ground. Bristles mainly have cutaneous respiration, but some species have gills. Most polychaete worms are dioecious animals. The eggs are fertilized in water. The development is indirect, in which free-living trochophore larvae emerge from the eggs, driven by cilia. The best-known members of the class are sandstone, nereid, and palolo.
In the eastern part of the Atlantic Ocean - the great Mediterranean and Black. Variable like shape, color and size. On waters with variable salinity: on the sea, sweetened or overworked lakes. A commune in the eastern Atlantic and across the Mediterranean. Thin, fragile, brittle fins. He is buried in the sands of the Razelm complex.
Throughout the northern Black Sea. Frequency between projectiles, beaches. In the eastern part of the Atlantic Ocean and across the Mediterranean Sea. On the great Mediterranean and Black. Numerous sandy beaches. In the Atlantic and Pacific Oceans, the Great Mediterranean and the Black. Brittle, white, translucent valves, with which he perforates strong clay deposits, from the mouth of the Danube to the Aguige. After storms, he appears on the beaches of Mamaia. The body is covered with white calcareous plaques and covered with a rhombic operation.
Sea Sandworm (Arenico / o marina) - marine polychaete worm living in the Black Sea and can reach 30 cm in length. He spends his whole life in a deep burrow of sand. It feeds on small algae, animals and various inanimate lobules, capturing them along with the sand. It is the main food for commercial fish.
Nereis (Nereis virens) , or Nereid,- polychaete worm living in the Sea of Azov. Refers to benthos - crawls along the bottom of the sea using event parameters. It is the main food for commercial fish. Acclimatized in the Caspian Sea, intensively bred there and became an important component in the diet of sturgeon fish.
A filter permanently placed on stones, sinks, columns, small ones, etc. In the zone of breaking waves. It consumes small plants and animals, living or decaying. In the sea, Black and Mediterranean basins. A small amphipod with a lateral frayed body. It lives in seaside sand, at a height of 0-10 m above sea level, or in sand covered with waves. Fish and birds are looking for him. About freshwater, freshwater and marine.
In the great Caspian, Black and Azov and on their limes. Take the color of the substrate you live on. Consume organic rainfall and worms. On sandy or graceful slopes, rarely rocky, up to 50 m above sea level. Long, 5-6 toothed. Yellowish shell with low calcium precipitation, transparent.
Palolo (Eunice viridis) - a marine polychaete worm that lives in the coral reefs of tropical Pacific islands. The color of the body is palolo greenish, the size is up to 1 m. Twice a year, in a certain phase of the moon, mature individuals appear in large numbers on the surface of the water for reproduction.
Small-bristle worms, or oligochaetes- a group of annelids, which have a few bristles on each segment of the body. This class includes more than 5000 species, which are mainly inhabitants of fresh water and soil, much less common in salt water. Most oligochaetes range in size from 0.5 mm to 40 cm, and some species of tropical earthworms reach 3 m. external structure oligochaete worms are segmentation of the body (from 5-6 to 600 rings), the absence of parapodia (in their place there are bundles of a few setae), the presence of a glandular belt in the anterior part of the body in mature individuals, etc. The most famous representatives of oligochaetes are earthworms and tubules.
Among algae, at a height of 10 m, rarely 50 m, in the Phyllofora deposits. Long soft belly on the sink. Move the shell over it; common on sandy beaches. Black Sea, Mediterranean Sea, Atlantic and Indian Oceans. An almost hexagonal hoop with a forehead and scalloped edges. Predatory, attacking shrimps, small fish, corpses. It can stay on land, with changes in salinity and temperature. In the coastal zone, under stones and in the Soest area, it was from 5 to 15 m above sea level.
Black Sea and Mediterranean Sea. Almost hexagonal hoop, with 3 strong front teeth and 4 on the sides of the carapace. Variable color by place of residence; abdominal - white-glossy. Nearly square square cephalotomy with the width of the cephalothorax forehead on the sides with a sharp tooth. Females have a large and round belly, males are small and triangular. On rocky ground; night falls on the ground. Balanus, algae, worms, etc. attached to the body.
common earthworm (Lumbricus terrestris) - a species of low-bristle worms that has adapted to life in the soil. These worms belong to the family of true earthworms, which includes about 300 species. Body sizes range from 2 to 50 cm. In the south of Ukraine, worms reach large sizes. Movement in the soil is facilitated by an elongated, segmented, pointed body at both ends. They move by alternately contracting and relaxing the annular and longitudinal muscles of the skin-muscle sac. The bristles directed backwards (8 on each segment) make it possible to cling to the slightest unevenness of the soil. The mucus secreted by the skin glands reduces the friction of the body of the worm, prevents it from drying out, promotes respiration, has
The internal structure of the earthworm: A - cuticle; B - hypodermis; B - circular muscles; G - longitudinal muscles; D - musculocutaneous sac; E - lining the epithelium; There is a ventral nerve chain; G - abdominal blood vessel; FROM - bristles; AND - methonephridia; AND - intestinal wall; TO - generally; L - dorsal blood vessel
antibiotic properties. Earthworms feed on dead plant residues contained in the soil. In the soil, earthworms dig deep passages up to 2 m from the surface of the earth. In warm and humid weather, they crawl out of their burrows at night, looking for damp fallen leaves, half-rotted blades of grass, and drag all this into the burrows. So, earthworms are typical saprophages. They also swallow soil, which can be seen in their intestines. Worms throw the processed soil to the surface in the form of characteristic heaps, the appearance of which in the spring indicates the beginning of the activity of the worms. It is estimated that each worm passes through its intestines such an amount of earth per day, equal to the mass of its body. More than 50 species of earthworms are known in Ukraine, some of them are listed in the Red Book of Ukraine (for example, Eizenia Gordeeva).
Ordinary tube (Tubifex tubifex) - freshwater red thin worm 2-5 cm in size. It lives in silty soils of fresh, very polluted water bodies with insufficient oxygen. The front end of the worm is immersed in silt, and the back end extends outward and continuously wriggles - these movements provide an influx of fresh water necessary for breathing. They can withstand significant pollution of water bodies by various substances (petroleum products, pesticides, etc.). In the skin of the back of the body, there are especially many blood capillaries. A tube is formed around this part of the body, consisting of silt particles glued together by the mucus of the worm. Swallows sand with silt and absorbs the nutrients that it contains. It is used as food for aquarium fish, is the basis of nutrition for freshwater animals, in particular fish.
medical leech (Hirudo medicinalis) has a segmented body 8-12 cm long. On the dark dorsal side of the body there is a characteristic pattern of three pairs of rusty-red or red-yellow longitudinal stripes. Lives in small stagnant reservoirs with a muddy bottom, overgrown with vegetation. It feeds on the blood of amphibians and mammals. The posterior sucker is used for attachment, while the anterior, which has jaws and teeth, is fed. In the oral cavity, located at the bottom of the anterior sucker, there are three jaws. They cut through the skin of the animal in which the leech has stuck. In the morning, saliva containing hirudin is secreted. Hirudin- a substance that is produced by the salivary glands of leeches to prevent blood clotting. Blood treated with leech saliva can be stored for a long time in large pockets of its intestines - thanks to this, the animal can starve for a long time (from several months to a year). Medical leech is a hermaphrodite, which is characterized by direct development. She lays her eggs in clusters near water (but not in water), in dark, damp places. Used in medicine for diseases of the circulatory system, gangrene and organ transplantation.
The body of which consists of repeating segments, or rings (hence their name - annelids).
General a brief description of annelids:
- there is a secondary body cavity (general);
- the body is covered on the outside with a cuticle secreted by the ectoderm.
- there is a circulatory system;
- the nervous system is represented by a paired supraesophageal ganglion connected by jumpers to the abdominal nerve chain (usually double);
- the excretory organs are located in each ring and are formed from the ectoderm, they are equipped with cilia;
Structure
The elongated body of annelids is, as it were, assembled from ring-segments, the segments are separated by internal partitions; but they are not completely independent, since a through intestine with a mouth and anus, an abdominal trunk of the nervous system and trunks of a closed circulatory system pass along the entire body. These organ systems, penetrating the partitions one by one, stretch through the entire body of annelids. Each ring-segment has a secondary body cavity (whole). Most of the segments bear on the outside, on the right and on the left, two tufts of setae - organs of locomotion or fixation in the tubes. In leeches, the bristles are secondarily lost.
Secondary body cavity (general)
The secondary cavity of the body (whole) is of mesodermal origin. It is surrounded by a mesodermal membrane and filled with fluid. The cavity occupies the space between the walls of the body and the intestinal tube. The main part of the mesoderm lining the secondary cavity is the muscles that make up the body wall. They provide the movement of the animal. In addition, the muscles of the intestinal wall, alternately contracting, push food.
The secondary body cavity performs the following functions:
The secondary body cavity, to one degree or another, is a characteristic feature for all types of multicellular animals that follow in evolutionary development, starting with annelids.
Classification
Annelids are a type of worms numerous in species that have a more complex body structure compared to flat and primary cavity worms. It is divided into three classes: Polychaetes, Belts (including subclasses Small-bristle worms and Leeches), Misostomids.
Origin
According to a comparative study of the structure of worms, annelids evolved from primitive whole worms, similar to flat ciliary worms. Important evolutionary acquisitions of annelids are the secondary body cavity (coelom), the circulatory system, and the division of the body into separate rings (segments). Polychaete annelids are the ancestral group for the rest of the annelids. From them, during the transition to a freshwater and terrestrial way of life, oligochaete worms separated. Leeches are descended from low-bristle worms.
On this page, material on the topics:
Report of annelids in Kamchatka
A short message about annelids
Annelids short summary
Annelids characteristic briefly
Celiac worms name of the body cavity
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