The main orders of insects. General characteristics of insect orders Table on biology diversity of insects

The class insects has two subclasses: primary wingless And winged.

TO subclass primary wingless These include insects whose ancestors never had wings (silverfish, springtails, etc.). Silverfish live in sheds and closets. basements. It feeds on decaying substances and is harmless to humans. When watering excessively, wingless insects - springtails - often appear in flower pots. They feed on rotted plants or their lower plants. The best way to combat them is to reduce watering.

Subclass of winged divided into insects with incomplete transformation and insects with complete transformation.

The distribution of species into orders is carried out taking into account such characteristics as the nature of development, structural features of the wings, and the structure of the oral apparatus. The main characteristics of some orders of insects are presented below.

Insects with incomplete metamorphosis

The most common are: squad of cockroaches- typical representative - red cockroach. The appearance of cockroaches in homes is a sign of sloppiness. They come out of their hiding places at night and feed on carelessly stored food, contaminating it. Female cockroaches carry a brown egg “suitcase” at the end of their abdomen - ooteku. They throw it in the trash. Eggs develop in it, from which larvae are born - small white cockroaches similar to adults. Then the cockroaches turn black, molt several times and gradually turn into adult cockroaches.

Termite squad- this includes social insects that live in large families in which there is a division of labor: workers, soldiers, males and females (queens). Termite nests - termite mounds - can be of considerable size. Thus, in African savannas, the height of termite mounds reaches 10-12 m, and the diameter of their underground part is 60 m. Termites feed mainly on wood, and can damage wooden buildings and agricultural plants. There are about 2,500 species of termites.

Order Orthoptera- most representatives of the order are herbivorous, but there are also predators. This includes grasshoppers, cabbage, locusts. The green grasshopper lives in the grass in the meadows and steppes. It has a long club-shaped ovipositor. Kapusyanka - has burrowing legs, flies and swims well. Causes great damage to the underground parts of garden plants, such as cucumbers, carrots, cabbage, potatoes, etc. Some types of locusts are prone to mass reproduction, then they gather in huge flocks and fly over a considerable distance (up to several thousand kilometers), destroying all green vegetation in the area. your way.

Squad of bedbugs- this includes known pests of agricultural crops - turtle bug, sucking the contents of the grains of cereal plants. Found in homes flea bug- a very unpleasant insect for humans. The water strider bug lives in fresh water bodies or on their surface, feeding on insects that fall into the water. Predatory bug attacks various invertebrate animals and fish fry.

Order Homoptera- all its representatives feed on plant juices. Many types aphids cause great harm to cultivated plants. Many homoptera are carriers of viral plant diseases. This includes a variety of cicadas, whose sizes range from a few millimeters to 5-6 cm. They live in the crowns of trees.

Granny squad- exceptional predatory insects. Adults attack prey in flight. The best flyers. Their flight is highly maneuverable: they can hover in the air, be mobile and can reach speeds of up to 100 km per hour. This includes rocker head, grandmother-watchman etc.

Insects with complete metamorphosis

Squad of beetles, or Coleoptera, is the most numerous order of insects, with up to 300,000 species. Beetles are distributed in a wide variety of different conditions land and fresh water bodies. Their sizes range from 0.3 to 155 mm in length. Many beetles cause great damage to cultivated plants. One of the pests of potatoes and other plants is Colorado beetle, brought to us from America. Beetle beetle- grain pest; cockchafer- its larvae damage tree roots and potato tubers; beet weevil- affects sugar beets. In addition, this includes bark beetles, grinding passages in the bark and bast fibers of valuable tree species, and the larvae goldenrod and i live in dead wood, causing great damage to forestry industries.

Many beetles spoil food supplies: pea weevil, bread beetle, carpet beetle, damaging leather and wool products. Another small beetle belongs to the order of beetles tube gun. The biology of these beetles is very interesting. In spring, the pipe cutter cuts the leaf down to the main vein in a special way. The cut part of the leaf fades and loses its elasticity. Then the beetle rolls it up into a ball and lays eggs there. Something like a cigar is formed. This is how the pipe roller expresses concern for its offspring.

Individual beetles feed on the remains of plants and animals and perform the role of orderlies in nature, for example: pustule beetles And gravestones. Some can be used to control pests. So, ladybug destroys aphids, and large green ones paint beetles- caterpillars.

Beetles can be extremely beautiful large sizes, For example stag beetle, or stag, listed in the Red Book, reaches a length of up to 8 cm, its larvae develop in rotten stumps for about five years and grow up to 14 cm in length. The reservoirs are inhabited by beetles of various sizes and feeding methods - the swimming beetle and the black water lover. The swimming beetle is a predator, the black water lover is a herbivore.

Butterfly squad, or Lepidoptera, - representatives of this order are distinguished by the varied colors of their wings. This includes hives, cabbage butterfly, silkworm etc. Among the species living in the Far East, there are very large moths, whose wingspan corresponds to the width of an unfolded notebook. The wings of butterflies are covered with modified hairs - scales, which have the ability to refract light. The iridescent color of the wings of many butterflies depends on this phenomenon. Butterfly larvae are called caterpillars. They have a gnawing apparatus and a long body. Their salivary glands, in addition to saliva, also secrete silk threads, from which a cocoon is woven before pupation. Adult butterflies are very good plant pollinators. The caterpillars of most butterflies are herbivorous, eating leaves of plants, causing significant harm, for example, cabbage whites, apple moths, lacewings, ringed silkworms, etc. The caterpillar of the house moth feeds on woolen products, damaging them; some caterpillars spoil flour and other food products.

Mulberry and oak silkworms- people have been breeding them for a long time in order to obtain silk (from cocoons). Many large butterflies are extremely beautiful, for example swallowtail, Apollo etc. The large butterfly is very interesting night peacock eye, on the wings of which there are ocellated spots. Its caterpillar is large, fleshy, green in color; before pupation, it weaves a cocoon the size of a chicken egg.

Large moths with sharp-angled wings, characterized by very fast flight - hawkmoths, - so named because they readily feed on fermented and odorous tree sap, especially birch sap, which appears on wounds and stumps.

Order Hymenoptera- unites a variety of insects: bees, bumblebees, OS, riders, sawflies etc. The lifestyle of these insects is varied. Some of them are herbivorous, as their larvae (very similar to caterpillars) cause great damage to crops and other plants, e.g. bread and pine sawflies. Sawfly larvae feeding on leaves become so similar to butterfly caterpillars that they are called false caterpillars. An amazing adaptation is the ovipositor of sawflies, which serves to cut out pockets in plant tissues in which female sawflies hide their eggs, thereby showing original care for their offspring.

Excellent plant pollinators are bumblebees. This is a social insect. The bumblebee family only exists for one summer. Nests are built in mouse holes, hollows, squirrel nests, and birdhouses. The female builds the nest, equipping wax cells in it for laying eggs. A supply of food is placed in the cell - a mixture of pollen and honey. The larvae emerging from the eggs eat food and after two to three weeks weave silk cocoons, turning into pupae. Working bumblebees, females and males, emerge from the pupae. By the end of summer, there are up to 500 bumblebees in large nests. In autumn, the old queen, males and workers die, and the young queens hide for the winter.

Lifestyle OS looks like a bumblebee. They also exist for one summer. Wasps are beneficial by destroying harmful insects, and the damage caused by them damaging fruits is small. More harm from hornets(one of the types of swarming wasps): they gnaw the bark of young trees and eat bees. Having settled near an apiary, they destroy thousands of bees over the summer.

Of the social insects of the order Hymenoptera, it is most beneficial honey bee. She is also a wonderful plant pollinator and produces exclusively useful product food - honey, as well as wax, royal jelly, widely used by humans in perfumery. medicine, for the manufacture of varnishes, paints, etc.

A bee family is a surprisingly complex whole, in which all members of the family are very closely related to each other. Life and prosperity of the entire species are equally impossible without the queen and without drones, without worker bees. Using knowledge about the lives of all members of the bee family, beekeepers have learned to create specialized houses for bees - hives, conditions for feeding bees (taken to the fields where honey plants are grown) and at the same time receive not only honey good quality, but also quantities.

Representatives of the order Hymenoptera are used as a biological method of combating harmful insects. These include various riders, as well as Trichogramma, which is bred artificially

Order Diptera. This includes well-known insects: flies, mosquitoes, midges, gadflies, horseflies and other insects similar to them, having one pair of transparent wings. The second pair of wings turned into the so-called halteres. The common mosquito lives in swampy and damp areas. Mosquitoes are especially numerous in mid-summer. Residents of the taiga and tundra call their clusters vile. With their piercing mouthparts, mosquitoes easily pierce human skin and suck his blood. Worm-like mosquito larvae live in stagnant water. While feeding, the larvae grow, molt and turn into mobile pupae. Mosquito pupae also live in water; they cannot feed, so they soon turn into adults.

The malaria mosquito and the common mosquito are distinguished by their position.

Common mosquito (squeaker) keeps his body parallel to the surface on which he sits, and malarial- at an angle to her, raising the rear end of the body high. The malaria mosquito lays eggs in a pond one at a time, while the common mosquito lays eggs in packs, floating on the surface in the form of rafts. Fungus gnat larvae live in the fruiting bodies of cap mushrooms.

flies, unlike mosquitoes. have short antennae. Their larvae are white, usually legless and headless. The housefly's worm-like larvae live and develop in kitchen waste, in piles of manure and sewage, where the fly lays its eggs. Before pupation, the larvae crawl out of the sewage, penetrate the soil and turn into pupae.

Adult flies hatching from pupae fly everywhere in search of poverty. From latrines and cesspools they fly onto openly lying food products and contaminate them. Flies transmit bacteria to human food gastrointestinal diseases and roundworm eggs. Therefore, it is very important to combat flies. Protect food from flies with gauze or hoods, wash vegetables and fruits before consumption.

Midges- long-whiskered bloodsuckers small sizes, the larvae of which develop at the bottom of reservoirs with running water. In the tropics and subtropics, in the Crimea there are very small mosquitoes - mosquitoes. Their larvae develop in moist soils, rodent burrows, etc. Mosquitoes are carriers of many diseases (malaria, etc.). We have a Hessian fly that destroys cereal plants.

Gadflies, horseflies They cause great harm to humans and domestic animals with their bites, as well as their ability to transmit pathogens of such dangerous diseases as tularemia and anthrax.

At the same time, flies are pollinators of many plants.

Rat flea can transmit plague pathogens from sick rodents - a very dangerous disease that once claimed thousands of human lives.

Insect with complete transformation (with metamorphosis) goes through four stages in its development: egg - larva - pupa - adult insect (imago).

Pay attention!

Orders of insects with complete transformation: butterflies (Lepidoptera), beetles (Coleoptera), Diptera, Hymenoptera, fleas.

Most species of insects are characterized by development with complete transformation. In insects with complete metamorphosis (butterflies, beetles, flies, wasps, ants), the larvae do not at all resemble adults. They have no compound eyes (there are only simple eyes, or no visual organs at all), often no antennae, no wings; the body is most often worm-shaped (for example, butterfly caterpillars).

In insects with complete metamorphosis, the larvae often live in completely different places and feed on different foods than adult insects. This eliminates competition between different stages of the same species.

Insect larvae with complete metamorphosis molt several times, grow and, having reached their maximum size, turn into doll. The pupa is usually motionless. An adult insect emerges from the pupa.

Watch a video that shows a Monarch butterfly emerging from its chrysalis.

Order Butterflies, or Lepidoptera

Butterflies differ from other insects mainly in two ways: scaly covering of wings and sucking mouthparts, rolled up in a spiral.

Butterflies are called Lepidoptera because they have small chitinous structures on their wings. scales. They refract the incident light, creating a bizarre play of shades.

The coloring of the wings of butterflies helps them recognize each other, camouflages them in the grass and on the bark of trees, or warns enemies that the butterfly is inedible.

Mouthparts of butterflies sucking- This is a proboscis curled into a spiral. Butterflies feed on the nectar of flowers.

Butterfly larvae (caterpillars) have gnawing mouthparts and feed on plant tissue (most often).

When pupating, the caterpillars of some butterflies secrete silk threads. The silk thread is secreted by a special silk gland located on the lower lip of the caterpillar.

Order Beetles, or Coleoptera

Representatives of this group have dense, hard elytra that cover the second pair of leathery wings, with which they fly. The mouthparts are gnawing.

Among the beetles there are many herbivores, there are predators and carrion eaters.

Beetles live in the ground-air environment (on plants, the surface of the earth, in the soil) and in water.

Beetle larvae are both very mobile predators, living openly, and sedentary, worm-like, living in shelters and feeding on plants, fungi, and sometimes decomposing remains of organisms.

Order Diptera

These insects have only one pair of wings. The second pair is greatly reduced and serves to stabilize the flight. This group includes mosquitoes and flies. They have piercing-sucking or licking mouthparts. Some dipterans feed on pollen and nectar of flowers (syrphid flies), there are predators (quackers) and bloodsuckers (mosquitoes, midges, midges, horseflies). Their larvae live in the decaying remains of cesspools, composts (house flies), in water (mosquitoes and midges) or lead a wandering lifestyle and prey on small insects.

Order Hymenoptera

The group includes such well-known insects as bumblebees, wasps, bees, ants, sawflies, and wasps. They have two pairs of membranous wings (some have no wings).

Insects are a class of arthropod invertebrate animals. According to the current classification, they, along with millipedes, are included in the tracheal-breathing subphylum. The name of the class comes from the word "flog". From the French "insecte" and the Latin "insectum" the concept is literally translated as "animal with notches." Let's look at these representatives of the fauna in more detail. At the end of the article the table “Orders of Insects” will be presented.

General information

The body of insects has a chitinized cuticle. It forms the ecoskeleton. The structure of insects is quite simple. It has three sections: head, abdomen and chest. Considering the structure of insects, there are three pairs of legs. They are attached to the thoracic region. In many groups, a pair of wings is attached to its second and third segments. Body size varies from 0.2 mm to 30 cm or more.

Life cycle

It involves the embryonic development of insects. It is called the "egg phase". The postembryonic period is also distinguished. It is accompanied by metamorphosis. It comes in two types. Depending on this, orders of insects with incomplete transformation are distinguished. They go through egg, larval and adult stages. Completed metamorphosis is characterized by four stages. In this case, the development of insects includes the phases of egg, larva, pupa and adult. In the former, the larvae have an external resemblance to the adults. The difference between them is the size of the body, the rudimentary state or complete absence of wings and genitals. The larvae of animals that go through four phases have a worm-like shape. Only adult individuals develop all the necessary characteristics of the order. At the adult stage, dispersal and reproduction occur. The insect class includes a wide variety of creatures. In total, more than a million species have been described. They are considered to be in nature and occupy all sorts of ecological zones. They are found everywhere, even in Antarctica.

Metamorphosis

Bedbugs

The Insect Orders table includes a variety of crop pests in this category. One of the famous ones is the turtle bug. It sucks the contents of grains from cereal plants. Flea bugs can be found in residential areas. This insect creates quite a lot of inconvenience for humans. The water strider bug lives in fresh water bodies. It feeds on insects that fall into the water. There are also predators among bedbugs, for example, the hungry bug. It attacks fish fry and various invertebrate animals. All representatives of this group are called hemiptera.

Other categories

Homoptera insects prefer to feed on plant juices. This category, for example, includes aphids. It exists in nature in a variety of forms and causes significant damage to crops. Homoptera insects are considered carriers of viral diseases dangerous to plants. For example, among them there are various cicadas, which can reach large sizes (up to 5-6 cm). The order Orthoptera includes predominantly herbivorous insects. However, you can also find predators among them. For example, representatives such as cabbage grass and locusts are quite well known. The grasshopper is also included in the order Orthoptera. It lives in grass, steppes and meadows. It has a club-shaped, long ovipositor. The kapustyanka swims and flies well and has burrowing legs. It causes great damage to the underground parts of plants that grow in the garden (cucumbers, potatoes, carrots, cabbage, etc.). Some locust species are characterized by mass reproduction. In such cases, they gather in huge flocks and fly away over long distances (up to several thousand kilometers). Along the way they destroy everything cultivated plants. The grandma order includes predatory insects. Their names are quite interesting. For example, grandma-yoke, grandma-dozoretsi and others. They are considered the best flyers. They are very maneuverable. They can hover in the air, exhibit exceptional mobility, and develop high speeds (up to 100 km/h). They attack their prey in flight.

Beetles

These are coleopterous insects. They are considered the largest community of all. Their number reaches 300 thousand species. Beetles live in a wide variety of fresh water and land conditions. Their body sizes vary from 0.3 to 155 mm. Many beetles cause great damage to crops. For example, the Colorado potato beetle is known throughout the world. It was brought to Russia from America. The borer beetle damages grain crops. The beet weevil causes damage to sugar beets. May beetle larvae damage potato tubers and tree roots. The bark beetle is also known. It grinds passages into the bark and damages valuable species. Many members of the order cause damage to food supplies. For example, these are the pea weevil, the carpet beetle, and the grain borer beetle. The detachment also includes a pipe-turner. In spring, this beetle cuts the leaf down to the main vein in a special way. Part of the plate fades and loses its elasticity. The beetle rolls it up and lays eggs there. This is how he takes care of his offspring. Beneficial insects are also present among the beetles. The names of such species are gloomy. For example, grobar beetles and pustule beetles. Many individuals are very beautiful in appearance and can reach impressive sizes. These, for example, are considered to be the stag beetle and stag beetle, which are included in the Red Book.

Group of diverse species

Hymenoptera insects are bees, wasps, wasps, bumblebees, sawflies and others. All these animals lead different lifestyles. Some representatives are herbivores. Their larvae cause significant damage to grain and other plants. Such, for example, are pine and grain sawflies. Their larvae are very similar in appearance to butterfly larvae. In this regard, they are often called false caterpillars. Sawflies have a very specific ovipositor. It is designed to cut out pockets in plant tissues in which females lay eggs.

bumblebees

They are very good pollinators. These hymenopteran insects are considered social. Their families exist only for one summer. They make their nests in hollows, nests, and birdhouses. The female is engaged in construction. She arranges wax cells for laying eggs. Each of them contains a supply of food - pollen mixed with honey. The emerging larvae eat the reserve, and after 2-3 weeks they begin to weave cocoons and turn into pupae. Working bumblebees, males and females, emerge from them. By the end of the season, a large nest can contain up to 500 individuals. By autumn, the old queen, worker bumblebees and males die. Young females hide for the winter.

Bees

They provide the greatest benefit of all social hymenopteran insects. Honey bees are considered excellent pollinators. They produce products that are very useful for humans: honey, royal jelly, wax, propolis. They are used for food, they are in demand in cosmetology, medicine, in the manufacture of perfumes, paints, varnishes, and so on. In a bee family, all members closely interact with each other. It is impossible for a species to flourish without drones and queens, working individuals.

Mosquitoes

These are dipterous insects. There are common and malaria mosquitoes. Their distinctive feature is the presence of one transparent pair of wings. The second pair turned into "halteres". The habitat of the common mosquito is damp, swampy areas. They become especially numerous by mid-summer. The mouthparts are equipped with a piercing proboscis. With its help, they pierce the skin and suck out blood. Mosquito larvae are worm-shaped. They live in stagnant water. There they develop, feed, gradually turning into pupae. They, in turn, also remain in stagnant water. However, since they cannot feed, they soon become adults. Common and malaria mosquitoes differ in their position. The first holds the body parallel to the surface on which it sits. The malaria mosquito lifts its hind end high.

flies

These are also dipterous insects. They, unlike mosquitoes, have short antennae. Their larvae are white, usually headless and legless. They are worm-shaped. Housefly larvae live and develop in sewage, manure heaps, and kitchen waste. This is where the female lays her eggs. Before pupation, the larvae crawl out of the waste, penetrate into the soil, where they turn into pupae. Adults fly everywhere and look for food. From cesspools they fly onto food products, carrying microbes and pathogens of dangerous gastrointestinal diseases.

Other groups

In nature, the lacewings exist in a relatively small group in terms of numbers. It has about 6 thousand species. Such insects have an elongated body with soft coverings. Their color is brown or pale green. Their two pairs of wings are covered with a network of veins. This group includes such representatives as antlions, lacewings, and mantips. Most lacewings are predators. They first appeared in the Permian period. The subsequent formation of the group took place under the influence of geological and climatic changes of the Mesozoic. The dragonfly insect is considered a very good flyer. These animals have a relatively large body. Their head is movable and has large eyes. The dragonfly insect lives mainly in humid subtropics and tropics. In the Russian Federation, it is widespread throughout almost the entire territory (except for arid areas).

Scheme

Natural enemies

According to the modern classification of the animal world, the following orders of insects with complete transformation (metamorphosis) are distinguished: order Reticuloptera, order Caddisflies, order Coleoptera, order Lepidoptera, order Diptera, order Fleas, order Hymenoptera, etc.

All species of these orders have stages in the development cycle: egg - larva - pupa - imago.

Order Reticulata– 4 wings, long, narrow, with few longitudinal and numerous transverse veins. The head is extended downwards into the proboscis. The mouthparts are gnawing. Species: Antlion. Its larvae live in holes they dig, where they catch ants that fall there. Adults look like small dragonflies.

Squad Caddisflies – There are 4 wings, the rear ones are larger and fold fan-shaped. The jaws form a proboscis. There are no mandibles. The larvae are similar to butterfly caterpillars and live in water, breathe through tracheal gills, and build themselves tubular houses from grains of sand and plant parts. Species: caddisfly.

Order Coleoptera– there are 4 wings, the front ones are turned into elytra and are not used for flight. The mouthparts are gnawing. The pupae are free (movable). Species: bark beetles. Plant pests.

Order Lepidoptera– there are 4 wings, they are covered with colored scales. The oral apparatus is sucking. The larvae are equipped with false legs and are called caterpillars. The pupae are not free (immobile). Species – different types of butterflies, moths, silkworms. Most species (adults and caterpillars) are plant pests. The silkworm is used by humans to produce silk.

Order Diptera– 2 wings, the hind ones are rudimentary and turned into ground beetles. The mouthparts are licking or piercing-sucking. The larvae are legless and headless. Pupae are free or barrel-shaped (immobile). Species – mosquitoes, flies, sand flies. They are pathogens or carriers of pathogens in humans and animals.

Flea Squad- no wings, body flattened laterally. The mouthparts are piercing-sucking. Species: dog flea, human flea. They are carriers of human and animal pathogens (plague, etc.).

Order Hymenoptera– 4 wings, lapping mouthparts. The larvae are often legless. Species: ants, bees, wasps, bumblebees. Meaning: give honey, propolis, wax (bees); ants are carriers of aphids, intermediate hosts in the development cycle of some helminths.

General characteristics orders of insects with incomplete metamorphosis

According to the modern classification of the animal world, the following orders of insects with incomplete transformation are distinguished: order Orthoptera, order Termites, order Dragonflies, order Bedbugs (hemiptera), order Homoptera, order Lice.

Order Orthoptera– the elytra are leathery, straightened along the back at rest, the hind wings are of a delicate structure. Sometimes the wings are underdeveloped. The mouthparts are gnawing. Species: locusts, cockroaches, grasshoppers. 3 purpose: plant pests (economic damage - locusts); mechanical carriers of human and animal pathogens (cockroaches).

Squad Termites- the front and rear wings disappear; they are present only in sexual individuals (there are also workers and soldiers). They live in communities, building termite mounds taller than a person. The mouthparts are gnawing. Meaning: pests of wooden buildings, furniture, books.

Dragonfly Squad– 2 pairs of wings, with a continuous mesh network of veins. The mouthparts are gnawing. In the development cycle there is a mobile nymph. The larvae live in water. Meaning: destroy insects (daytime predators).

Squad Bedbugs– there are 4 wings, the front ones are half rigid, and membranous towards the free end. The mouthparts are piercing-sucking. Species - water striders (harmless), bed bug - mechanical carrier of human pathogens.

Order Homoptera– 4 wings, all identical, with a sparse network of veins. The mouthparts are piercing. Species: aphids, cicadas. Meaning: plant pests.

Troop Lice– no wings (secondary wingless). The mouthparts are piercing-sucking. Types: head, clothes, pubic lice. Meaning: head and body lice are carriers of human pathogens, and are also the causative agents of human disease - pediculosis.

GENERAL CHARACTERISTICS

TYPE OF SHELLFISH

The phylum Mollusca belongs to the subkingdom Multicellular, the kingdom Animals, the superkingdom Eukaryotes, and the empire Cellular. The phylum includes 7 classes, of which three are the most common: the Gastropod class (small pond snail, bitinia), the Bivalve class (toothless, pearl barley), and the Cephalopod class (squid, octopus). In total, there are about 100,000 species in the phylum (Fig. 60).

Mollusks live mainly in seas and fresh water bodies, less often on land. They lead a free lifestyle. These are three-layered animals. Dimensions – a few cm.

The body is solid (non-segmented). Consists of a head, torso and legs. In most species it is enclosed in a calcareous shell various shapes. The shell consists of 3 layers: outer – organic, horny; middle – calcareous; internal – mother-of-pearl.

On the inside of the shell, the entire body is covered by a skin fold - the mantle, due to the activity of which the shell is formed. The space between the body and the mantle is called the mantle cavity. The respiratory organs, secretions, ducts of the gonads and intestines open into it.

The organ of movement is the leg. This is a muscular unpaired outgrowth of the ventral side of the body.

The secondary body cavity in most species is reduced and is represented by the pericardial sac and the cavity of the gonads. In the spaces between the organs there is a loose layer of connective tissue cells - parenchyma.

The nervous system is of a scattered nodular type or in the form of cords dotted nerve cells. Nerves extend to all organs. In species leading an active lifestyle, at the head end there are large nerve nodes - the “brain” and complex sensory organs: touch (tentacles), vision (eyes).

The digestive system begins with the mouth opening, followed by the pharynx (in gastropods, it houses a muscular tongue-grater). Next comes the esophagus, stomach, intestines, into which the liver duct opens, and the digestive tube ends with the anus.

Excretory system – kidneys of the metanephridial type, which are highly modified metanephridia. One end of the tubular kidney faces the pericardial sac (coelom), and the second opens into the mantle cavity.

The circulatory system is not closed. The heart consists of one ventricle and one or more atria. The blood washes all the organs, then collects in the vessels going to the gills, and then the oxygenated blood enters the heart.

Respiratory system– in most species, the respiratory organs are gills located in the mantle cavity. Land and freshwater mollusks have lungs.

3 purpose: commercial (for food, for obtaining pearls); crushed shells - feeding birds; pests of agricultural plants; intermediate hosts of helminths; destroyers of wood structures.

General characteristics of the class Gastropods

The class Gastropods belongs to the phylum Mollusca, subkingdom Multicellular, kingdom Animalia, superkingdom Eukaryotes, empire Cellular. There are about 90,000 species in the class (grape snail, slugs, small pond snail, etc.). According to their lifestyle, these are free-living organisms, they live in the seas and fresh water bodies, and there are terrestrial species. The body of gastropods is three-layered, asymmetrical, ranging in size from 2-3 mm to 60 cm, oblong in shape, convex on the back.

The body is divided into head, torso and leg; covered with a mantle and enclosed in a shell. The shell is entire, sometimes reduced. The head on the ventral side has a mouth, and on the dorsal side there are 1-2 pairs of tentacles and a pair of eyes. The front pair of tentacles is the organ of touch; at the top of the second pair there are eyes. The front part of the head, which bears the mouth, often extends into a long trunk. The leg is a muscular abdominal outgrowth with a flat, crawling sole. Movements are carried out by contracting the leg muscles. The trunk or visceral sac in most species protrudes above the leg in the form of a large curled sac. On the body, in a downward direction, a fold of integument is formed - a mantle fold, under which there is a mantle cavity.

The nervous system is of a scattered-nodular type. There are 5 pairs of large nerve ganglia located in different parts of the body and connected to each other by cords. Nerves extend from nodes to organs. The sense organs - touch and vision - are located on the head.

The digestive system is represented by the intestinal tube, which is divided into sections: mouth, pharynx, esophagus (in some species it has an extension - goiter), stomach, midgut and hindgut. In the pharynx there is a tongue with cuticular thickenings, the so-called jaws. The ducts of the salivary glands flow into the pharynx; their secretion in some predatory species contains free sulfuric acid (up to 4% strength). The liver duct flows into the saccular stomach. Liver secretions break down carbohydrates. The liver absorbs nutrients and stores glycogen and fat. The hindgut opens with powder outwards.

The excretory system is a kidney of the metanephridial type, which removes liquid metabolic products from the coelom to the mantle region.

The circulatory system is not closed. There is a heart, consisting of a ventricle and atrium, and blood vessels. The blood in the heart is arterial.

The respiratory system in most aquatic species is represented by gills, in terrestrial species - by primitive lungs, and some species breathe over the entire surface of the body. The lungs are special pockets of the mantle. Their walls are densely intertwined with a network of blood capillaries.

Reproductive system. Most species are hermaphrodites, but there are also dioecious species. Cross fertilization. Development is direct. Meaning: harmful– pests of agricultural crops, intermediate hosts in the development cycle of helminths, useful– commercial object (food, shells for crafts).

General characteristics of the class Bivalve

The class Bivalves belongs to the phylum Molluscs, subkingdom Multicellular, kingdom Animalia, superkingdom Eukaryotes, empire Cellular. There are 16,000 species in the class - the toothless mussel, sea and freshwater pearl mussels, oysters, mussels, blackbird (shipworm), etc.

Bivalves live in marine and fresh waters, lead a free lifestyle. The body dimensions of bivalve mollusks range from several cm to 2 m. The body of bivalve mollusks is three-layered, bilaterally symmetrical, consisting of a trunk and legs (the head is reduced), enclosed in a bivalve shell. The shell valves are connected to each other by an elastic ligament, which is located on the dorsal side of the animal. In addition, the doors are connected with a “lock”. This is a connection with the help of odontoid processes of the dorsal edge of one valve, which enters the corresponding pits of the dorsal edge of the other valve. To close the shell valves, there are closing muscles. The shell consists of three layers: a thin outer stratum corneum, a thick middle calcareous layer and a thin inner nacreous layer.

The body of bivalves is covered with a mantle, which forms two folds on the sides. Between the body and the folds is the mantle cavity. In many species, the mantle folds can grow together in places, forming openings (siphons), usually three or two small posterior ones and one large one. The upper rear opening serves to remove water and excrement from the mantle cavity, the lower one serves to introduce water into the mantle cavity, which serves for respiration and brings food. Through big hole a leg sticks out. Along the free edge of the mantle there may be tentacles and eyes. Both shell valves are distinguished by the outer epithelium of the mantle.

The leg is a muscular outgrowth. In many species it is equipped with a flat crawling sole. In some species it is flattened on the sides and sharpened like a knife blade, so it is used not so much for crawling as for digging sand or silt in which animals hide. In immobile forms (mussels, oysters), the leg is reduced or disappears. A number of species have a special gland (byssus) on the sole of the foot, which secretes viscous threads of secretion that quickly hardens in water. With the help of these threads the animal is attached to underwater objects.

The nervous system is scattered and nodular. It usually consists of 3 pairs of ganglia: peripharyngeal, pedunculated and located under the hindgut. The ganglia are connected to each other by nerve trunks. Sense organs are poorly developed: eyes, balance organs, chemical sense organs.

The digestive system begins with the mouth opening, surrounded by two pairs of tentacles, followed by a short esophagus, which passes into a rounded stomach, followed by the midgut and hindgut, which opens powdery into the mantle cavity. Bivalves do not have a tongue, pharynx, jaws, or salivary glands in their digestive system. Their food is plankton.

The excretory system consists of two kidneys of the metanephridial type - tubular sacs that carry liquid metabolic products from the coelom (pericardial space) to the outside.

The circulatory system is not closed. The heart consists of a ventricle and two atria, located on the dorsal side. The respiratory system is represented by gills. Reproductive system - most species are dioecious. Sex glands: testes and ovaries are paired and open into the mantle cavity, where insemination occurs. There is no sexual dimorphism. Development is external, with incomplete metamorphosis.

Meaning: useful– commercial (oysters, scallops, mussels are used as food; lime flour is prepared from the shells, which is used as animal feed; pearls and nacre are obtained from barley and pearl mussels); harmful– pests of woody structures (ships, piles, houses).

GENERAL CHARACTERISTICS

TYPE CHORDATES

The integument of the body is represented by skin, consisting of multilayered epithelium, skin itself and their derivatives (scales, feathers, hair).

Despite the diversity of species, all chordates have a common structural plan and differ from representatives of other types in four main characters.

1. They have an internal axial skeleton, represented by a notochord. It either remains in adult animals for life, or is replaced by a cartilaginous or bony skeleton - the spinal column. The notochord is a flexible elastic rod that develops from the endoderm and consists of highly vacuolated cells.

2. The central nervous system is located on the dorsal side above the notochord. It looks like a tube stretching along the body and has an internal cavity - the neurocoelum. The neural tube develops from the ectoderm and in vertebrates differentiates into the brain and spinal cord.

3. On the anterior section of the digestive tube (pharynx) of the embryo, the gill apparatus develops. It is represented by gill slits that pierce the wall of the pharynx, and a skeleton (visceral arches). The gill apparatus either remains throughout life, as an organ of aquatic respiration, or is reduced during the development of the embryo.

4. The central circulatory organ - the heart or a vessel replacing it - is located on the abdominal side and is formed in the embryo under the digestive tube.

All chordates are three-layered animals, have bilateral body symmetry, have a secondary body cavity and a secondary mouth. They have major organ systems: musculoskeletal, nervous, digestive, excretory, circulatory, respiratory, reproductive and endocrine.

3meaning: are a link in the general food chain, used by humans (meat, eggs, fat, fluff, feathers, wool, leather, snake venom); are intermediate hosts or carriers of human pathogens, etc.

General characteristics of the Lancelets class

The class Lancelets belongs to the subphylum Lancelets, the phylum Chordata, the subkingdom Multicellular, the kingdom Animalia, the superkingdom Eukaryotes, and the empire Cellular. Modern lancelets include 20 species of small fish-like animals. They live in the seas in the zone of coastal sands. They lead a bottom lifestyle, burying themselves in the sand. They feed passively on plankton.

The body of lancelets is narrow, elongated, flattened laterally. Dimensions 8-10 cm. On the dorsal side there is a fold of skin - the dorsal fin. The caudal end of the body is edged with an unpaired caudal fin, which continues on the ventral side only in the posterior part, and paired metapleural folds run along the sides of the body (Fig. 61).

The skin of the lancelet is formed by smooth skin, consisting of two layers: single-layer epithelium and the skin itself, consisting of gelatinous tissue. Under the skin, striated muscles are located in the form of separate segments, with connective tissue layers lying between them. The axial skeleton of lancelets is the notochord. It lasts the entire life of the animal. There are supporting septa around the notochord and neural tube and between muscle segments. The skeleton of the unpaired fin consists of dense gelatinous rods. Similar rods form the skeleton of the gill apparatus. The internal organs of lancelets lie in a secondary cavity - the coelom.

The central nervous system is represented by a tube located above the notochord. It is not differentiated into the brain and spinal cord. The neural tube contains the light-sensitive ocelli of Hesse. Peripheral nerves arise from the neural tube in the form of paired dorsal and ventral roots, one pair for each segment.

The digestive system begins with the mouth, which lies deep in the preoral funnel, followed by the pharynx, midgut and hindgut, which opens outward through the anus. The voluminous pharynx makes up half the entire length of the intestinal tube. Its walls are cut through by 150 pairs of gill slits leading into the peribranchial cavity, which opens outwards with an opening - the atrial pore. At the bottom of the pharynx there is a groove covered with ciliated epithelium. Food particles are carried by a current of water into the oral cavity, then along the groove of the pharynx by the cilia of the epithelium they move into the midgut. The duct of the intestinal outgrowth opens into it, performing the functions of the digestive gland. The process of digestion and absorption of nutrients occurs in the midgut. Fecal masses are formed in the hindgut, which are thrown out. At the same time, the pharynx performs the function of breathing. The gill septa are densely intertwined with capillaries. Water, washing the gill membranes, releases oxygen into the blood of the capillaries.

The circulatory system is closed, there is one circle of blood circulation, there is no mixed blood. There is no heart; its role is played by the pulsating abdominal aorta. The blood is colorless.

The excretory system of lancelets is represented by paired metamerically arranged nephridia located on the sides of the pharynx. Each nephridia is a tube, one end facing the whole; the opposite end of the nephridia opens into the atrial cavity, from where excretory products are discharged out through the atrial pore.

The reproductive system is represented only by gonads: testes in males and ovaries in females. The gonads are located in paired metameric rows on the sides of the body. The reproductive system does not have excretory ducts. After maturation, the germ cells, when the gonad wall ruptures, enter the atrial cavity and are then released into the external environment. Insemination and development in lancelets is external.

Meaning: are a link in the overall food chain; are of great theoretical importance for understanding the origin of vertebrates.

General characteristics of the class Bony fish

The class Bony fish belongs to the superclass Pisces, the Anamnia group, the embryo does not have an aquatic shell), the subphylum Vertebrates, the phylum Chordata, the subkingdom Multicellular, the kingdom Animalia, the superkingdom Eukaryotes, the empire Cellular. There are about 20,000 species in the class. All of them live in water, lead a free lifestyle, many species are predators. Fish are three-layered, bilaterally symmetrical animals. Body sizes range from several cm to several meters. The body shape is streamlined, flattened laterally, which promotes rapid movement in the water (Fig. 62).

The body is divided into head, trunk and tail. The integument of the body is skin, consisting of two layers: stratified epithelium and the skin itself with its derivatives (scales). The skin contains many glands that secrete mucus, which reduces friction when the fish moves. Movement is carried out by paired pectoral and ventral fins, as well as unpaired dorsal, caudal and anal fins. The mobility of fins, gill covers and body bends are provided by striated muscles that lie under the skin. Muscular system retains a metameric structure.

The skeleton of a fish consists of a spine, ribs, fins and a skull. The spine is divided into the trunk and caudal sections, formed by numerous vertebrae, the upper arches of which limit the spinal canal, where the spinal cord is located. In the trunk section of the spine, the ribs are attached to the vertebrae. There are no ribs in the caudal region. The skull is divided into a dorsal part (the cranium), where the brain, organs of vision, smell and taste are located, and an abdominal part, which forms gill arches and jaws with conical teeth for holding food. The body cavity is secondary.

The nervous system is represented by the brain and spinal cord and the nerves extending from them. The brain is divided into 5 sections: forebrain, intermediate, midbrain, cerebellum and medulla oblongata. The forebrain hemispheres are poorly developed and serve as the highest olfactory center. The midbrain reaches the largest size. Due to the complex coordination of movements, the cerebellum is well developed. Well developed sense organs. The olfactory organ is represented by a pair of closed olfactory sacs. The eyes are equipped with eyelids, the lens is almost spherical in shape, adapted for vision at close distances. The organ of hearing and balance is represented only by the paired inner ear. The taste organs - microscopically small taste buds - are located not only in the oral cavity, but also on the surface of the body. The peculiar sensory organs of fish are the lateral line organs. They are located in a special channel running along the sides of the body from the head to the caudal fin. The channel communicates with the external environment through numerous small holes. The lateral line organs allow the fish to orient itself in relation to the direction of water movement.

The digestive system begins with the oropharyngeal cavity, from which the esophagus extends. The stomach is not always separated from the midgut, but has great extensibility, especially in predatory fish. Some of them can swallow prey equal in size to themselves. The duodenum extending from the stomach sometimes forms several blindly ending appendages. It receives secretions from the liver and pancreas. The intestinal tube is differentiated into the small and large intestine. The latter opens with the anus outward.

Many species of bony fish have a hydrostatic organ - a swim bladder. When the bladder is filled with gas, specific gravity the volume of fish decreases, and it passively rises to the surface of the water, and when the amount of gas in the bubble decreases, it sinks to the bottom of the reservoir. Gas enters the swim bladder from the blood capillaries that surround the wall of the bladder.

The excretory system is represented by paired primary (trunk) kidneys. They lie on both sides of the spine in the form of ribbon-like bodies. From the kidneys come the ureters, which merge into one unpaired duct that flows into the bladder. The latter opens outward with a special opening behind the anus.

The circulatory system of bony fish is closed, with one circle of blood circulation. Either arterial or venous blood flows through the vessels. The heart is two-chambered, consisting of one ventricle and one atrium. The blood in the heart is venous, it is collected from internal organs and tissues into a common vessel flowing into the atrium. From it, blood enters the ventricle, and then through the abdominal aorta is sent to the gills, where gas exchange occurs. Arterial blood from the gills collects in the dorsal aorta, which, breaking up into smaller arteries, delivers arterial blood to organs and tissues.

The respiratory system of bony fishes is represented by the gill apparatus - gill arches, gill filaments and gill covers. Water washes the gill filaments through the gill slits, releases oxygen dissolved in it into the blood, becomes enriched with carbon dioxide and comes out from under the gill cover. Each gill septum bears a gill consisting of two semi-branchs.

The reproductive system is represented by paired testes in males, and paired ovaries in females. The vast majority of fish are dioecious animals, but there are also hermaphrodites ( sea ​​bass, sea crucian). Insemination and development external.

Eggs (eggs) and seminal fluid with sperm are released into the external environment, where fertilization occurs. This process is called spawning. In the fertilized egg, the embryo develops, which then leaves the egg shell and turns into a larva. The latter grows into a fry, which, upon reaching sexual maturity, turns into an adult.

General characteristics of the class Amphibians

The class Amphibians (Amphibians) belongs to the Anamnia group, the subphylum Vertebrates, the phylum Chordata, the subkingdom Multicellular, the kingdom Animalia, the superkingdom Eukaryotes, and the empire Cellular. The class is divided into 3 groups: the Legless group (caecilians), the Tailed group (newts, salamanders); detachment Tailless (frogs, toads). In total there are about 2000 species in the class. This is a dying class (Fig. 63).

The distribution of amphibians is limited to areas with high temperature and humidity. Habitat: shores of fresh water bodies, damp soils. In tropical rainforests, some species have adopted an arboreal lifestyle. Most amphibians are sedentary. Their movements are monotonous (which is due to unstable body temperature, poor development of the lungs and circulatory system).

According to their lifestyle, they are free-living insectivores. Tailless amphibians have a short body, flattened in the dorsoventral direction. The hind limbs are longer than the forelimbs. In caudates, the body is elongated, laterally compressed, with long tail and short legs.

The skin consists of two layers: the epidermis and the dermis with numerous glands that secrete mucus. Mucus covers the entire body, protecting the skin from drying out and promoting better gliding in water. In some species, mucus is poisonous, i.e., it performs a protective function. The skin of amphibians is penetrated by a dense network of blood vessels and performs the function of respiration in water.

The skeleton of amphibians is bony, consisting of a braincase, spine and limbs. The spine is divided into 4 sections: cervical, trunk, sacral and caudal. The cervical and sacral regions appear for the first time and have one vertebra each. In tailless animals, the vertebrae of the caudal region merge into one bone. The trunk vertebrae of tailed amphibians bear short ribs that do not reach the sternum. Anurans have no ribs. The free forelimbs include: shoulder, forearm, hand; rear - thigh, lower leg, foot. In typical cases, the limbs have five fingers. The forelimb girdle consists of paired crow bones, scapulae and clavicles. The hind limb girdle consists of three pairs of fused pelvic bones: the ilium, the ischium and the pubis. The braincase is small and flattened.

The muscles are striated, located in segments and provide movement. The muscles of the limbs are more significantly developed. The body cavity is secondary.

Nervous system - consists of the brain and spinal cord and the nerves extending from them. The brain consists of 5 sections: the forebrain, intermediate, midbrain, cerebellum and medulla oblongata. The forebrain is better developed than in fish and is clearly divided into two hemispheres. The cerebellum is poorly developed. The midbrain has visible thalamus. There are 10 pairs of cranial nerves leaving the brain. Spinal nerves arise from the spinal cord and form the brachial and lumbosacral plexuses.

Amphibians' sense organs become more complex. Paired olfactory capsules communicate not only with the external environment (nostrils), but also with the oral cavity, where the choanae open. In this regard, the nasal cavity becomes a through passage through which air enters the lungs. The eyes are equipped with three pairs of eyelids, which protect them from drying out on land. The third eyelid is transparent, which allows you to see well in water, while at the same time protecting the eyeball from damage. The lens flattens, which increases the distance at which the animal sees objects. The structure of the hearing organ becomes significantly more complicated. It consists of two sections: the inner and middle ear, closed by the eardrum. In water, the middle ear is covered by a fold of skin.

Digestive system - begins with the oropharyngeal cavity, which passes into the esophagus. The oral cavity contains conical teeth and a tongue. The ducts of the salivary glands also flow here. A short esophagus leads to a separate stomach. This is followed by the duodenum, where the ducts of the liver and pancreas flow. The large intestine receives the ducts of the reproductive and urinary systems and forms the cloaca.

The excretory system is represented by two primary kidneys, two ureters and a bladder. The kidneys of amphibians in the form of ribbons are located along the spine and remove liquid waste products partly from the body cavity, and mostly from the blood through the ureter into the cloaca, where the bladder opens.

Respiratory system: breathing in amphibians is cutaneous-pulmonary. On land, the respiratory organs are the lungs - paired bags with a highly extensible cellular wall, permeated with dense blood vessels. In water, the function of respiration is performed by the skin.

The circulatory system is closed. In connection with the appearance of lungs, a second (pulmonary, pulmonary) circulation develops in amphibians, but the separation of the circulation circles is incomplete and there is only one ventricle, so in most of the arteries of the systemic circle the blood is mixed (with the exception of the carotid arteries, which carry blood to the head).

The heart is three-chambered, consisting of two atria and one ventricle. One large vessel departs from the heart - the conus arteriosus, which divides into two aortic arches. The latter, bending around the heart on the right and left, merge into one large vessel - the dorsal aorta, from which smaller vessels depart to all organs and tissues.

Reproductive system - all amphibians are dioecious animals. Gonads are paired. The seminiferous tubules open into the ureter. Eggs from the ovary enter the body cavity, from there they are released through the oviducts into the cloaca. Insemination is external, development is external with complex metamorphosis.

3limited value. Destroy harmful insects, their larvae, small rodents; are a link in the overall food chain; used in some countries for human food; are the object scientific research(frog). Aromorphoses of amphibians - a five-fingered limb of the terrestrial type; lungs – organ of atmospheric respiration, second (small, pulmonary) circle of blood circulation, 3-chamber heart; middle ear and complication of the organ of vision.

General characteristics of the class Reptiles

Class Reptiles (Reptiles) are true terrestrial animals. The class belongs to the Amniota group (their embryo has a water membrane - the amnion), to the Vertebrate subphylum, the Chordata type, the Multicellular subkingdom, the Animal kingdom, the Eukaryotic superkingdom, and the Cellular empire. Modern reptiles are divided into 4 orders: the Beaked order (Gatteria), the Scaly order (snakes, lizards, chameleons), the Turtle order, and the Crocodiles order. In total, there are about 6000 species in the class (Fig. 64).

Reptiles are cold-blooded animals, so they have adapted to live in tropical forests, deserts, and waterless steppes. Reptiles living in water (crocodiles, turtles) are secondary aquatic, since their ancestors switched from a terrestrial lifestyle to life in the water. Among reptiles leading a free lifestyle, there are herbivores and predators. Body sizes range from several cm to several meters.

The body of reptiles is divided into head, neck, torso, tail and limbs. It is covered with dry skin, devoid of glands, which gives appendages - scales, scutes. Only some species have preserved odorous glands, the secretion of which repels or, conversely, attracts other animals. The skeleton is bony and is represented by the skull, spine, skeleton chest, belts of the fore and hind limbs, bones of the front and hind limbs. Skull with elongated jaws in the form of a snout.

The spine is divided into 5 sections: cervical, thoracic, lumbar, sacral and caudal. IN cervical spine up to 8 vertebrae. The thoracic vertebrae are joined by the ribs, which on the ventral side are attached to the sternum, forming the rib cage.

The lumbar vertebrae also bear ribs, the ends of which end freely.

The girdle of the forelimbs is formed by the sternum, two crow bones, two clavicles, and two shoulder blades. The free forelimbs consist of the shoulder, forearm and hand. The girdle of the hind limbs is formed by three pairs of fused pelvic bones: the ilium, the ischium and the pubis. The free hind limbs consist of the thigh, tibia and foot. The humerus and femur bones are located horizontally to the surface of the earth, so the body of reptiles sags and drags along the ground. The body cavity is secondary.

The muscular system is represented by striated and smooth muscles. For the first time, the intercostal muscles appear, taking part in the act of breathing. Powerful chewing and neck muscles develop.