Reference material for oge in biology. levels of organization of life. General methods of biology

Block 3. System, diversity and evolution of living nature

Kingdom Animals

TYPE CHORDS. SUPERCLASS FISH

Fish are the largest group of vertebrates. Fish are classified into the class Cartilaginous fishes (sharks, rays ) and class Bony fishes (sturgeon, salmon, herring, crucian carp, pike, swordfish and etc.). The main criterion for such a division is the substance that makes up the internal skeleton of fish:cartilage or bone.

Animals of this, the most prosperous group of vertebrates today, can be found in all corners of our planet - from the North Pole to the South. They are also found in the brackish waters of the seas and oceans, and in the fresh waters of lakes and rivers; live in the dark depths of ocean trenches, and in sun-drenched coral reefs. The number of their forms is innumerable, and each fish is in amazing harmony with its environment.

Fish are a large group of vertebrates. The branch of zoology that studies fish is calledichthyology .

general characteristics fish

Fish are vertebrates that live in water (in an environment much denser than air). The body of a fish is remarkably adapted to the implementation of all vital functions in the water. The body of the fish is usually covered with scales and has a streamlined shape. It consists of three parts:heads, torsos and tail . The main respiratory organ is the gills. Like other vertebrates, fish have a solid skeleton, muscles, skin, digestive, circulatory and nervous systems, respiratory, excretion and reproduction organs.

Fish are cold-blooded animals: their body temperature is close to the ambient temperature. Therefore, we can say that the rate of metabolic processes depends on the temperature of the water.

Today, about 25 thousand species of fish are known.

Habitat and external structure of fish

The habitat of fish is various water bodies of our planet: oceans, seas, rivers, lakes, ponds. It is very extensive: the area occupied by the oceans exceeds 70% of the Earth's surface, and the deepest depressions go 11 thousand meters deep into the oceans.

The variety of living conditions in the water influenced the appearance of fish and contributed to a wide variety of body shapes: the emergence of many adaptations to living conditions, both in structure and in biological features.

General plan of the external structure of fish

On the head of the fish are eyes, nostrils, mouth with lips, gill covers. The head smoothly merges into the body. The trunk continues from the gill covers to the anal fin. The body of the fish ends with a tail.

Outside, the body is covered with skin. Protects the skin of most slimy fishscales .

The locomotion organs of fish arefins . The fins are outgrowths of the skin that rest on the bones.fin rays . The tail fin is the most important. From the bottom on the sides of the body are paired fins: pectoral and ventral. They correspond to the fore and hind limbs of terrestrial vertebrates. The position of the paired fins varies from fish to fish. The dorsal fin is located on top of the body of the fish, and the anal fin is located below, closer to the tail. The number of dorsal and anal fins may vary.

On the sides of the body of most fish is a kind of organ that perceives the flow of water. This islateral line . Thanks to the lateral line, even a blinded fish does not run into obstacles and is able to catch moving prey. The visible part of the lateral line is formed by scales with holes. Through them, water penetrates into a channel stretching along the body, to which the endings of nerve cells fit. The lateral line may be intermittent, continuous or completely absent.

Fin functions

Thanks to the fins, the fish is able to move and maintain balance in the aquatic environment. Deprived of fins, it turns over with its belly up, since the center of gravity is placed in the dorsal part.

unpaired fins (dorsal and anal) provide body stability. The caudal fin in the vast majority of fish performs the function of a mover.

Paired fins (thoracic and abdominal) serve as stabilizers, i.e. provide an equilibrium position of the body when it is immobile. With their help, the fish maintains the body in the desired position. When moving, they serve as bearing planes, a steering wheel. The pectoral fins move the fish's body when swimming slowly. The pelvic fins perform mainly the function of balance.

body shape

Fish have a streamlined body shape. It reflects the characteristics of the environment and lifestyle. In fish adapted to fast long swimming in the water column (tuna (2), mackerel, herring, cod, salmon ), "torpedo-shaped" body shape. In predators practicing fast throws at a short distance (pike, taimen, barracuda, garfish (1), saury ), it is "arrow-shaped". Some fish adapted to long stay at the bottom (stingray (6) , flounder (3) ) have a flat body. In some species, the body has a bizarre shape. For example,sea ​​Horse resembles the corresponding chess piece: its head is at right angles to the axis of the body.

body integuments

Outside, the skin of fish is covered with scales - thin translucent plates. Scales with their ends overlap each other, arranged in a tile-like manner. This provides

strong protection of the body and at the same time does not create obstacles to movement. Scales are formed by special skin cells. The size of the scales is different: from microscopic toacne up to several centimetersIndian barbel . There is a wide variety of scales: in shape, strength, composition, quantity and some other characteristics.

Lie in the skin pigment cells - chromatophores : when they expand, the pigment grains spread over a larger area and the color of the body becomes bright. If the chromatophores contract, pigment grains accumulate in the center, leaving most of the cell uncolored, and the color of the body turns pale. If the pigment grains of all colors are evenly distributed inside the chromatophores, the fish has a bright color; if the pigment grains are collected in the centers of the cells, the fish becomes almost colorless, transparent; if only yellow pigment grains are distributed over their chromatophores, the fish changes color to light yellow.

Chromatophores determine the diversity of fish coloration, especially bright in the tropics. Thus, the skin of fish performs the function of external protection. It protects the body from mechanical damage, facilitates sliding, determines the color of the fish, and communicates with the external environment. The skin contains organs that sense temperature and chemical composition water.

Peculiarities internal structure and life of fish

Musculoskeletal system fish consists of a skeleton and muscles. The basis of the skeleton is formed by the skull and spine.Spine consists of individual vertebrae. Each vertebra has a thickened part - the vertebral body, as well as the upper and lower arches. The superior arches together form a canal in which the spinal cord lies. The arches protect him from injury. Up from the arcs stick out longspinous processes . The lower arcs in the trunk part are open. Adjacent to the lateral processes of the vertebraeribs - they cover the internal organs and serve as a support for the trunkmuscles . Especially powerful muscles are located in fish in the back and tail. In the caudal part, the lower arches of the vertebrae form a canal through which blood vessels pass.

The skeleton also includes bones and bone rays.paired and unpaired fins . The skeleton of unpaired fins consists of many elongated bones, reinforced in the thickness of the muscles. Paired fins have skeletonsbelts and skeletons free limbs . The skeleton of the pectoral girdle is motionlessly attached to the skeleton of the head. The skeleton of the free limb (the fin itself) includes many small and elongated bones. In the abdominal girdle - a single bone. The skeleton of the free ventral fin consists of many long bones.

In the skeleton of the head, a smallscull, or cranium . The bones of the skull protect the brain. The main part of the skeleton of the head is made up of the upper and mandibles, bones of the eye sockets and gill apparatus. In the gill apparatus, largegill covers . If you lift them up, you can seegill arches - they are paired: left and right. On the gill arches are the gills. There are few muscles in the head part, they are mainly located in the area of ​​the gill covers, jaws and on the back of the head.

Muscles are attached to the bones of the skeleton, which provide movement by their work. The main muscles are located evenly in the dorsal part of the body of the fish; the muscles that move the tail are especially well developed.

The musculoskeletal system performs various functions in the body. It serves as a support, allows you to move, protects from shocks and collisions. The skeleton protects the internal organs. Bony fin rays are a weapon of defense against predators and rivals.

Digestive system begins with a large mouth located at the end of the head and armed with jaws. There is an extensive oral cavity. There are small or largeteeth . Behind the oral cavity is the pharyngeal cavity. It shows gill slits separated by intergill septa. They have gills. They are covered with gill covers from the outside. This is followed by the esophagus and the voluminous stomach. Behind the stomach is the intestine. In the stomach and intestines, food is digested under the action of digestive juices: gastric juice acts in the stomach, in the intestines - juices secreted by the glands of the intestinal walls and pancreas, as well as bile coming from the gallbladder and liver. In the intestines, digested food and water are absorbed into the blood. Undigested residues are thrown out through the anus.

The digestive system provides the fish with essential nutrients.

The swim bladder is a special organ found only in bony fish. It is located in the body cavity under the spine. During embryonic development, it appears as a dorsal outgrowth of the intestinal tube. In order to fill the bubble with air, a newborn fry floats to the surface of the water and swallows air into the esophagus. Later, the connection of the swim bladder with the esophagus is interrupted.

Interestingly, with the help of the swim bladder, some fish are able to amplify the sounds they make. In some fish species, this organ is absent (for example, those living on the bottom or those that are characterized by rapid vertical movements).

The swim bladder prevents the fish from drowning under its own weight. It consists of one or two chambers, filled with a mixture of gases close in composition to air. The volume of gases in the swim bladder can change when they are released and absorbed through the blood vessels of the bladder walls or when air is swallowed. This changes the body volume of the fish and its specific gravity. Thanks to the swim bladder, the body weight of the fish comes into balance with the buoyant force acting on the fish at a certain depth.

Respiratory system located in the pharynx.

The skeletal support of the gill apparatus is provided by four pairs of vertical gill arches, to which the gill plates are attached. They are made up of fringedgill filaments , inside which pass thin-walled blood vessels branching into capillaries. Gas exchange occurs through the walls of the capillaries: the absorption of oxygen from water and the release of carbon dioxide. Water moves between the gill filaments due to the contraction of the muscles of the pharynx and the movement of the gill covers. There are gill rakers on the gill arches. They protect soft tender gills from clogging with food particles.

Circulatory system fish is schematically a vicious circle consisting of vessels. Its main organ is the heart. Ittwo-chamber: consists of atrium and ventricle . The work of the heart ensures blood circulation. Moving through the vessels, the blood carries out gas exchange, the transfer of nutrients and other substances in the body.

The circulatory system of fish includesone circle of blood circulation . From the heart, blood flows to the gills, where it is enriched with oxygen. Oxygenated blood is calledarterial . It spreads throughout the body, gives oxygen to the cells, is saturated with carbon dioxide, that is, it becomesvenous and returns to the heart. In all vertebrates, the vessels that depart from the heart arearteries . The vessels that lead to the heart areveins .

excretory organs filter from the blood and remove water and end products of metabolism from the body. The excretory organs are presented in pairs.kidneys along the spine,and ureters . Some fish have bladder.

Extraction from the branched blood vessels of excess fluid, salts, harmful metabolic products occurs in the kidneys. Urine enters the bladder through the ureters and is expelled from it. The urinary canal opens outward through an opening located behind the anal. Through these organs, excess salts, water and metabolic products harmful to the body are removed from the body of the fish.

Metabolism - a set of chemical processes occurring in a living organism . Metabolism is based on two phenomena: the construction and decay of organic substances. Complex organic matter, entering the body with food in the process of digestion turn into less complex. They are absorbed into the blood and carried to the cells of the body, where they form the proteins, fats and carbohydrates necessary for the body. This takes energy, which is released during breathing. At the same time, many substances in the cells decompose into water, carbon dioxide and urea. Thus,metabolism consists of the processes of building and breaking down substances .

The metabolic rate of fish depends on body temperature. Fish are cold-blooded animals with variable body temperature. The body temperature of the fish is close to the ambient temperature and does not exceed it by more than 0.5–1.0 degrees (although in tuna, the difference can be up to 10 degrees).

Nervous system is responsible for the coherence of the work of all systems and organs, the implementation of the body's reactions to environmental changes. Like all vertebrates, in fish it consists of the head, spinal cord(central nervous system) and nerves extending from them (peripheral nervous system).Brain consists of five departments:front , including visual lobes,middle, intermediate, cerebellum and oblong brain. All active pelagic fish have large optic lobes and cerebellum as they require good vision and fine coordination. The medulla oblongata passes into the spinal cord, which ends in the caudal spine.

With the participation of the nervous system, the body responds to various stimuli. This reaction is calledreflex . In the behavior of fish are manifestedunconditional and conditional reflexes. Unconditioned reflexes are otherwise called innate. In all animals belonging to the same species, unconditioned reflexes manifest themselves in the same way. Conditioned reflexes produced during the life of each fish. For example, by tapping on the glass of the aquarium every time you feed, you can ensure that the fish will begin to gather near the feeder just to knock.

sense organs fish are well developed. The eyes are adapted to clearly recognize objects at close range, to distinguish colors. Through the inner ear - an organ located inside the skull - fish perceive sounds. Odors are recognized through the nostrils. In the oral cavity, in the skin of the antennae, lips, there are organs of taste that determine sweet, sour, salty.

The direction and strength of the water current perceiveslateral line . It is formed by a channel passing inside the body, which communicates with the aquatic environment through holes in the scales. Sensory lateral line cells respond to changes in water pressure and transmit signals to the brain.

Features of reproduction and development of fish

Reproductive organs . Almost all fish separate sexes . For reproduction, special paired organs are used: in males -testicles (milk), vas deferens, in females -ovaries , oviducts. In the testes, male germ cells develop - spermatozoa, in the ovaries - female germ cells - eggs (eggs). For their withdrawal, there is a special genital opening. In some species of fish, males and females differ in color and body shape. Biologists call this phenomenon sexual dimorphism.

Sexual dimorphism is manifested in the external differences of individuals of the opposite sex (based on these differences, they recognize and choose each other). A vivid example of sexual dimorphism is an exceptionally peculiar species of males and females of some deep-sea fishes -anglers .

Small males, only a few centimeters in size, attach themselves to the body of much larger females. Or rather, they grow, because at the same time their circulatory system becomes an appendage of the female's circulatory system. From this point on, males become incapable of independent existence. They are needed only for the production of offspring.

Reproduction and development of fish. With the maturation of germ cells in fish, the instinct of reproduction is manifested. The reproduction of fish is calledspawning . Readiness for spawning is signaled by the behavior of the fish and mating coloration. Some fish are spawningmigration , moving to places more suitable for the development of their future offspring.Salmon, eels and a number of other fish overcome great distances.

Spawning females lay eggs, which are fertilized by males. Fish lay eggs on clusters of algae, lumps of mucus, bubbles of foam at the surface of the water, in pits at the bottom, etc. Fertilization is external - occurs in the environment.

When the sex cells merge, an egg is formed, which matures in water. The embryo develops inside the egg. The mature embryo of the fish is released from the membranes, enters the water and from that moment is called the larva. Over time, the larva begins to feed independently on microscopic algae, ciliates, and then small crustaceans. In case of survival, it becomes like an adult fish, it is calledfry .

In many species of fish, enormous fecundity serves as an adaptation for survival. so femaleriver perch lays 200-300 thousand eggs, femalecarp 400-600 thousand eggs, and the femalecod up to 10 million. There are fish that lay a small amount of caviar. However, these fish show concern for offspring. For example,stickleback three-spined lays only 60-70 eggs. In a special way, care for the offspring ofseahorses, pipefish, tilapia . There are also viviparous species of fish. With a live birth, the number of born cubs is reduced to tens and units. Some sharks and rays lay eggs with a well-developed large embryo. These eggs have special devices for attaching to plants.

Growing up, the fry pass to the "adult" life, enter the feeding period. Having reached puberty, the fish begin to reproduce.

The process of reproduction is very significant for the survival of the species. As a result of evolution, fish have developed suchcomplex behaviors , as spawning migrations (salmon, sturgeon, freshwater eel ), care for offspring (three-spined stickleback, seahorse etc.), mating "dances". All these are adaptations of species to living conditions, survival next to other types of organisms.

Migrations. As we found out, fish in the process of life cycle go through the following stages: egg, larva, fry, fattening, sexually mature individual. Some fish, for examplesalmon , migrations are necessarily present in the life cycle. The first three stages (they take from 2 to 5 years of life) salmon spend in rivers. Then comes the time of the first migration, and juvenile salmon roll down the rivers into the sea. Here, moving and feeding on a vast area, salmon develop rapidly (foraging) and reach sexual maturity.

After that, salmon begin the second (spawning) migration to their native rivers, where they find their way by the smell of water. Fish rise to the upper reaches of the river and spawn. This ends the cycle of reproduction. Weakened parents drift downstream. Many die, but many survive for subsequent migrations and spawning.Far Eastern salmon (pink salmon) dies after spawning. Fish that migrate from rivers to seas or from seas to rivers are calledcheckpoints . These include many types of herring, salmon, sturgeon. These fish, like salmon, breed in rivers and feed in the sea. Anadromous fish need freedom of movement in rivers. Therefore, their survival requires the creation of special devices to help them bypass hydroelectric dams. Some species of fish have special adaptations in the structure of their bodies, allowing them to overcome various obstacles and obstacles on the way to spawning grounds.

Migrations of acne. Lives in the rivers of EuropeEuropean river eel . Eels can reach 2 m in length and 6 kg in weight. River eel refers to anadromous fish. The river eel has a juvenile stage, spawning migration and spawning take place in the sea, and growth and fattening take place in fresh water. Eel can stay for a long time in its main habitats - quiet backwaters of rivers. At the onset of puberty, the eel changes appearance (the diameter of the eyes increases, the back turns from olive green to black, and the abdomen becomes silvery white), rolls into the sea and stops eating. It is known that eel spawning migrations in the Baltic Sea pass through coastal waters, and, starting from the North Sea, their trace has not been studied. In the end, the eel ends up at its spawning site: off the coast of America in the Sargasso Sea. Having spawned at a depth of 300–400 m, the eel dies. The larvae emerging from the eggs (they are calledleptocephali ) are so unlike their parents that they were at one time considered a different kind of fish.

These eel larvae, having appeared in the Sargasso Sea, emerge into the upper layers of the water, are picked up by the currents that arise in the western part of the North Atlantic, and drift for 2.5–3 years to the shores of Europe. During this migration, the body of eels undergoes quite complex transformations. Transparent three-year-old eel fry (glass eels) appear in flocks off the coast of Europe. Next, male eels are fattened in brackish waters. And females enter rivers, migrate upstream, settle in various water bodies and live in fresh water for at least a few years. They feed on small fish, caviar, frogs. With the onset of puberty, it is time to go to their native places.

Not all questions related to the long-term migrations of European eels have been clarified. In addition to the river eel, such migrations are characteristic of some species of gobies and tropical species of catfish.

Caring for offspring in seahorses. An exemplary father among fish issea ​​Horse . Widespread in the seas and oceans, skates have a solid body covered with plates of the external skeleton. On the abdomen of the male there is a pocket that opens outwards only with a small opening.

For the entire breeding season, the skates form a permanent pair, which occupies a certain area in the sea thickets. If any stranger encroaches on this territory, the male will drive him away. During spawning, the female places eggs inside the male's brood pouch, which develop there. The tissues of the brood pouch contain a large number of small blood vessels through which the eggs are supplied with oxygen. Spawning usually occurs several times, so small skates in the male's pouch can be of different ages, and then the older generation leaves the paternal pouch with an interval of several days.

Sometimes the father's concern does not end there, and fully formed young skates that have already left the bag, in case of danger, can again briefly return under the protection of their father.

Live birth. Some species of fish do not lay eggs, but give birth to cubs that have developed inside the mother's body. In this case, the development of the larva occurs directly in the oviducts of the female due to the nutrients present in the eggs. Viviparous fish species include not only sea giants (sharks, rays), but also very small fish (aquariumguppies, swordsmen ).

The value of fish in nature and human life. Protection and breeding of fish

role in nature. About 70% of the Earth's surface is covered with water, or rather, with aquatic biogeocenoses: stable communities of living organisms that have developed in the process historical development Earth. Each species, as an inhabitant of one or another biogeocenosis, has developed characteristic adaptations to life in communities. Each species plays its own unique role here.

In aquatic biogeocenoses, fish enter into various relationships with other organisms. Considering, for example, the food chains of aquatic biogeocenoses, one can be convinced that fish eat a large number of animal and plant organisms. But they themselves, in turn, serve as food for many other organisms. Relationships in which different types of animals are interconnected with mutual benefit (symbiosis) are very interesting. How does it happen inamphiprion (clown fish) and anemones.

hydroid polyps that help them camouflage themselves on the bottom. Hydroid polyps, in turn, find a means of transportation in fish.

The value of fish in human life.Fishing one of the oldest forms economic activity of people. Fish for humans is a source of very valuable nutrients, mainly animal proteins and fats, and these products are more easily absorbed by the human body than vegetable ones.

Fish (especially bone ones) are of great practical importance for humans. Apart from food products, fish serve as a raw material for obtaining medicines (fish oil, etc.), feed for livestock and poultry (feed meal), fertilizers for fields, technical fat, glue, leather and other materials used in the food and light industries. There are countries where the well-being of the population directly depends on fishing.

Up to 90% of the mass of fish is caught in the seas and oceans. The main objects of the marine industry arecod, haddock, saffron cod, pollock, herring, herring, sardine, sea bass, flounder, saury, mackerel, tuna . In the rivers of Russia they catch sturgeon, salmon,ram, roach, zander and other fish. Meat, fat, caviar are used for food.

Millions of people are engaged in catching, breeding and processing fish, building ships and making fishing equipment.

Hundreds of thousands of people are fond of fishing and spearfishing, to whom this wonderful sport gives health and relaxation. Even more hobbyists are creating a colorful, quiet world in the glass containers of their aquariums.

Fish protection. Marine fisheries are currently experiencing great difficulties. They are associated with pollution. water resources(due to accidents of oil tankers; pollution caused by the development of minerals; discharges of coastal runoff). In addition, using modern powerful means of fishing, you can completely catch all the fish and thereby not only stop further fishing, but also cause irreparable harm to nature. To prevent this from happening, special measures are taken to protect and reproduce fish.

Ecology says: the most unstable factors for the existence of fish today are the purity of water, the air regime, and the safety of species habitats. And offers the basic principles of environmentally friendly activities near water bodies and in water bodies.

The basis of the stability of biogeocenoses is the diversity of species. In order for aquatic biocenoses to always exist, it is necessary to preserve fish species by all means, and first of all, those that are threatened with extinction (due to deteriorating environmental conditions, overfishing or other factors).

Laws on the protection and use of the animal world of the planet are adopted by world organizations. In particular, all fishing enterprises, as well as amateur fishermen, are required to strictly observe the established fishing rules. The laws define the methods and seasons of fishing. The diameter of the meshes of the nets should be such as not to impede the exit of juveniles from them. On the rivers and ponds of Russia, the use of nets is strictly prohibited, as well as the killing of fish by explosions (after all, almost the entire population of this section of the reservoir dies). Much attention should be paid to the installation of treatment facilities that prevent water contaminated by sewage from factories and plants from entering rivers, lakes and seas.

Valuable fish. Rare fish of the world and Russia are of particular scientific and biological value. Among them, we note species that are found only in a given habitat (they are calledendemic ). Endemic to Russia is, for example,Kaluga , swimming from the sea to the Amur. Many endemic fish species live in Lake Baikal. These species must be protected as a special natural value.

From an industrial point of view, for example, sturgeon and salmon fish are of great value. Their meat and caviar are delicious and nutritious!

The features of individual fish species are valued and used by humans. So, exported from Americagambusia settled to fight mosquitoes. After all, she feeds on their larvae.

Variety of fish

Studying the diversity of fish, ichthyologists divide them into different groups. So, depending on the attitude to the environment, all fish are divided into marine, freshwater and anadromous.

maritime species are the majoritysharks, rays , many herring and other fish.

To freshwater include, for example, cyprinids:roach, dace, asp, tench, barbel, bream, bleak, sabrefish, carp, crucian carp, grass carp . In fresh waters, an important factor determining the distribution of fish is the flow of water.Bream lives only in running water. Butcrucians, rotans can live in small ponds and swampy lakes.

To those living in both fresh and sea water (i.e.checkpoint ) include sturgeon, salmon,freshwater eel etc. Anadromous fish are usually able to adapt to strong fluctuations in water salinity. In addition, during the life cycle, they need to prepare the body for high energy costs associated, for example, with overcoming currents.

In addition, among fish there arepelagic , i.e. living in the water column (herring, horse mackerel, cod, tuna ), and bottom , i.e. living near the bottom (flounder, catfish ).

There are peaceful fishherbivores types (eg. silver carp ) and very aggressivepredators (pike, perch, catfish ).

Class Cartilaginous fish

Fish with a cartilaginous, non-ossifying skeleton are classified asclass Cartilaginous fish . These fish do not have gill covers. On each side of the body, 5–7 pairs of gill slits separated from each other open freely. Among the cartilaginous fish, three orders are distinguished:Sharks, Rays, Chimeras .

Shark Squad. There are over 250 species of sharks. Their sizes are different. For example,midget shark , living in the Gulf of Mexico, does not exceed 20 cm in length and weighs no more than 500 g. Awhale shark has a length of 18–20 m and a mass of about 10 tons. The skin of sharks is rough, covered with scales with numerous teeth. The external structure of the shark reflects all the adaptations to life in the water column: a torpedo-shaped body, a sharp nose, dark above and light below the body color.

Paired pectoral and ventral fins provide the shark with up and down movement. The upper lobe of the caudal fin is usually longer than the lower lobe. Vision is black and white. Sharks have a well-developed sense of smell, with which they search for prey. They live mainly in the seas. Most are active predators. They prey on fish, shrimps, aquatic mammals. The whale shark feeds on plankton.herring sharks - viviparous fish. They are found in the Atlantic and Pacific Oceans in temperate and subtropical waters. Most dangerous to humansbrindle and blunt sharks, hammerhead shark, mako and big white . Sharks are an object of fishing. Shark liver is considered a valuable product, which occupies 20-30% of body weight.

Squad Squad. About 350 species of stingrays are known. These are large fish with a flat diamond-shaped body flattened in the dorsal-ventral direction. On the sides it is formed by expanded pectoral fins. When moving, the fins move in waves.

The sizes of the slopes are different. The smallest slopeDiptera from yellow sea- has a width of 10-15 cm. The largest representative of the detachment -manta - in the span of fins reaches 8 m and has a mass of about 2.5 tons.

On the ventral side of the body of stingrays, a transverse mouth opens with a powerful grater of teeth, as well as five pairs of gill slits. Many have spines (skin teeth) on their scales. They feed on bottom animals: mollusks, worms, crabs, fish.

The tail of the stingrays is extended into a whip. At the end of the tail, stingrays have a spike with a poisonous gland.

Some tropical species of rays have electric organs. Electrical discharges up to 300 volts are produced, probably for protection purposes. The electrical processes in the muscle tissue of rays have not yet been adequately explained. Stingrays are objects of fishing. Some are dangerous to humans.

The Chimera order is a representative of the subclass Whole-Headed or Solid-Cranial. In chimeras, the jaws are completely fused to the skull; in this they strongly resemble bony fish. The gill slits are covered with a skin fold. There is no cloaca, the anal and urogenital openings are separated from each other. A naked body up to 1.5 m long, gradually thinning, passes into a long tail.

It is believed that chimeras originated from ancient sharks and are a side branch of evolution. Wholeheads have been known since the Upper Devonian; at present, only a detachment of chimeras exists. Of more than a dozen of his families, only 3 have survived to this day; about 30 species living from the shelf to great depths of the oceans. Chimeras feed on marine invertebrates and fish. They have practically no commercial value.

Class Bony fish

Bony fish are a class of aquatic vertebrates. All structural features of fish are determined by the environment in which they live. Long-term adaptation to life in the water has not left a single extra detail that interferes with movement.

Body sizes range from 0.7 - 0.9 cm (Philippine goby ) up to 17 m ( herring king ); blue marlin weighs up to 900 kg. The body shape is usually elongated and streamlined, although some bony fish are flattened in the dorsal-ventral direction or from the sides, or vice versa are spherical. The translational movement in the water is carried out due to the wave-like movements of the body. Some fish at the same time "help" themselves with a caudal fin. Paired lateral, as well as dorsal and anal fins serve as stabilizer rudders. In some fish, individual fins have been transformed into suckers or copulatory organs.

Outside, the body of bony fish is covered with scales: placoid (teeth laid "in the parquet"),ganoid (rhombic plates with a spike),cycloid (thin plates with a smooth edge) orctenoid (plates with spines), periodically changing as the animal grows. Annual rings on it allow you to judge the age of the fish.

In many fish, mucous glands are well developed on the skin, their secretions reduce the resistance to the oncoming flow of water. In some deep-sea fish, luminous organs develop on the skin, which serve to identify their species, consolidate the flock, lure prey, and scare away predators. The most complex of these organs are similar to a searchlight: they have luminous elements (such as phosphorescent bacteria), a mirror reflector, a diaphragm or lens, and an insulating black or red coating.

The color of the fish is very diverse. Usually, fish have a bluish or greenish back (the color of the water) and silvery sides and belly (hardly visible against the background of a light "sky"). Many camouflage fish are covered with stripes and spots. The inhabitants of coral reefs, on the contrary, amaze with a riot of colors.

Variety of bony fish

Bony fish include most types of fish. They are subdivided into bone-cartilaginous, lungfish, lobe-finned and bony.

The bone-cartilaginous, or sturgeon, fish includebeluga, sterlet, Russian sturgeon . They have a bone-cartilaginous skeleton with a well-developed chord, there are gill covers, a swim bladder. Along the body of sturgeon there are 5 rows of bone plates, between which are small bone plates. The head, like that of sharks, has an elongated snout. Near the mouth, located on the underside of the head, there are antennae. The caudal fin is unequal.

Sturgeons: beluga (1), Siberian sturgeon (2), sterlet (3), stellate sturgeon (4), common shovelnose (5), paddlefish (6).

Sturgeon - anadromous fish northern hemisphere. They live up to 50–100 years or more. These fish are widely known for their particularly tasty meat and black caviar. A typical representative of sturgeons -Russian sturgeon , a common inhabitant of the Volga-Caspian and Black Sea basins. Spends most of the time at sea, spawning in rivers. The sturgeon feeds mainly on annelids and molluscs. For the winter, it lies in deep holes, most often in the mouths of rivers. Currently, the number of sturgeons is small.

Lungfish - a small (only 6 species) ancient group of fish. Among themAustralian horntooth, African and south american flake . In lungfish, the notochord is preserved throughout life, the vertebral bodies do not develop, which indicates their antiquity. Unpaired fins have a feathery structure characteristic of the subclass. The upper jaw is fused to the skull. Along with gills, these fish have lungs that have developed from the swim bladder. Some lungfish, rising to the surface, can swallow atmospheric air. The elongated body can reach a length of 2 m. These fish can wait out a long drought by burrowing into the silt. The structure of the heart has also changed: the atrium is divided by an incomplete septum into the left and right halves. The right half receives blood from the gills, and the left half receives blood from the lungs.

Dipnoi: cattail (barramunda) (7), lepidosirenus (8), large protopter (mamba) (9).

Lungfish - freshwater fish that live in stagnant or drying up water bodies.

Australian horntooth (more than 1 m long) lives in rivers heavily overgrown with plants. In summer, when reservoirs become shallow, breaking up into a chain of pits - barrels with rotting water, it completely switches to breathing atmospheric air. Having put its snout above the water, it throws out the “exhausted” air with force and at the same time makes a groaning-grunting sound that spreads far around the neighborhood. Horntooth feeds on mollusks, crustaceans, worms, insect larvae.

Other representatives of the lungfish -African flake (up to 2 m long) and South American flake (up to 1 m long) during the drying up of reservoirs they are buried in silt and hibernate.

The lobe-finned fish are an ancient group of fish. Until the first half of the XX century. they were considered an extinct branch of vertebrates, once widespread both in fresh water bodies and in the seas. The crossopterans are close to the lungfish. Their skeleton was mostly cartilaginous. The notochord was absent in adult fish. The fins of the crossopterans were similar to the fins of the horntooth, the swim bladder turned into a paired lung, and the nostrils communicated with the oropharynx. Currently, one modern representative is known -coelacanth , a descendant of marine crossopterans.

Coelacanth - large fish (up to 180 cm long). Her body is covered with massive scales, and her fins (especially paired ones) look like fleshy lobes. Coelacanths live at the bottom, at a depth of up to 400 m (possibly deeper), in the southwestern part of the Indian Ocean. They feed on fish.

Bony fish are the most numerous group of modern fish (about 96% of all species). Their skeleton is ossified, the notochord develops only in embryos, and the scales are bony. They usually have a swim bladder. Bony fish include such valuable commercial species astuna, halibut, salmon, herring, pike other. Common to our riverscarp and bream - also bony fish. These fish live in almost all water bodies of the Earth.

Herrings: Atlantic herring (10), Japanese anchovy (11), European sprat (sprat) (12), sardinella (13).

This group includes fishherring detachments (herring, sardines, anchovies , two types of which are called hamsa),salmonids (noble salmon , or salmon, chum salmon, pink salmon, chinook salmon, sockeye salmon, whitefish, grayling, smelt ), cyprinids (chub, roach, bream, ide, dace, asp, carp, crucian carp ), catfish (catfish ), cod-like (cod, saffron cod, haddock, blue whiting, pollock, burbot ), flatfishes (flounder, halibut ). There are more than 40 units in total.

Cell structure, cell division, protein biosynthesis. Reproduction. Development -

Ontogenesis

Properties of living structures:

1) self-updating. The basis of metabolism is the interrelated processes of assimilation (anabolism, synthesis, formation of new substances) and dissimilation (catabolism, decay);

2) self-reproduction. Nucleic acids are capable of storing, transmitting and reproducing hereditary information, as well as realizing it through protein synthesis. Information stored on DNA is transferred to a protein molecule with the help of RNA molecules;

3) self-regulation. It is based on a set of flows of matter, energy and information through a living organism;

4) irritability. Associated with the transfer of information from the outside to any biological system and reflects the reaction of this system to an external stimulus

5) maintenance of homeostasis - the relative dynamic constancy of the internal environment of the body

7) adaptation - the ability of a living organism to constantly adapt to changing conditions of existence in the environment;

8) reproduction (reproduction

9) heredity. Due to heredity, traits are transmitted from generation to generation that provide adaptation to the environment;

10) variability - due to variability, a living system acquires features that were previously unusual for it

11) individual development (the process of ontogenesis). During this process, such a property as the ability to grow is manifested, which is expressed in an increase in body weight and size;

12) phylogenetic development. Based on progressive reproduction, heredity, struggle for existence and selection. As a result of evolution, a huge number of species appeared;

13) discreteness (discontinuity) and at the same time integrity. Each organism, in turn, is also discrete, since it consists of a set of organs, tissues and cells.

Squirrels are polymers whose monomers are amino acids Functions of proteins: 1) protective; 2) structural; 3) motor; 4) spare; 5) transport; 6) receptor; 7) regulatory; 8) hormone proteins are involved in humoral regulation; 9) enzyme proteins catalyze all chemical reactions in the body; 10) energy.

Carbohydrates - these are mono- and polymers, which include carbon, hydrogen and oxygen Functions of carbohydrates: 1) energy; 2) structural; 3) storage.

Fats (lipids) can be simple or complex. Simple lipid molecules consist of the trihydric alcohol glycerol and three fatty acid residues. Complex lipids are compounds of simple lipids with proteins and carbohydrates. The functions of lipids: 1) energy; 2) structural; 3) storage; 4) protective; 5) regulatory; 6) heat-insulating.

The ATP (adenosine triphosphoric acid) molecule is formed in mitochondria and is the main source of energy.

5. Protein biosynthesis. Genetic code

There are 2 types of nucleic acids - deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

DNA is a helix consisting of two complementary polynucleotide chains twisted to the right. Two chains of nucleotides are connected to each other through nitrogenous bases according to the principle of complementarity: two hydrogen bonds occur between adenine and thymine, and three between guanine and cytosine.

DNA functions:

1) ensures the preservation and transmission of genetic information from cell to cell and from organism to organism (replication);

2) regulates all processes in the cell, providing the ability for transcription with subsequent translation.

Replication occurs during the synthetic period of the interphase of mitosis. The replicase enzyme moves between the two strands of the DNA helix and breaks the hydrogen bonds between the nitrogenous bases. Then, to each of the chains, using the DNA polymerase enzyme, the nucleotides of the daughter chains are completed according to the principle of complementarity. As a result of replication, two identical DNA molecules are formed. The amount of DNA in a cell doubles. This method of DNA duplication is called semi-conservative, since each new DNA molecule contains one "old" and one newly synthesized polynucleotide chain.

RNA is a single stranded polymer. There are 3 types of RNA.

1. Messenger RNA (i-RNA) is located in the nucleus and cytoplasm of the cell, performs the function of transferring hereditary information from the nucleus to the cytoplasm of the cell.

2. Transfer RNA (t-RNA) is also found in the nucleus and cytoplasm of the cell, delivers amino acids to ribosomes during translation - protein biosynthesis.

3. Ribosomal RNA (r-RNA) is found in the nucleolus and ribosomes of the cell.

Protein biosynthesis occurs in several steps.

1. Transcription is the process of mRNA synthesis on a DNA template.

2. Then processing occurs - the maturation of the RNA molecule.

Transcription takes place in the cell nucleus. The mature mRNA then enters the cytoplasm through pores in the nuclear membrane, and translation begins.

3. Translation is the process of protein synthesis on the matrix and RNA.

Genetic code This is a system for encoding the amino acid sequence of a protein as a specific sequence of nucleotides in DNA and RNA.

A unit of the genetic code (codon) is a triplet of nucleotides in DNA or RNA that codes for one amino acid.

In total, the genetic code includes 64 codons, of which 61 are coding and 3 are non-coding (terminator codons).

Terminator codons in i-RNA: UAA, UAG, UGA, in DNA: ATT, ATC, ACT.

The genetic code has characteristic properties.

1. Universality - the code is the same for all organisms.

2. Specificity - each codon codes for only one amino acid.

Prenuclear prokaryotes do not have a typical nucleus. These include bacteria and blue-green algae.

Prokaryotes originated in the Archean era. These are very small cells ranging in size from 0.1 to 10 microns.

A typical bacterial cell is surrounded on the outside by a cell wall, the basis of which is the substance murein and determines the shape of the bacterial cell. On top of the cell wall there is a mucous capsule that performs a protective function.

Under the cell wall is the plasma membrane. The entire cell inside is filled with cytoplasm, which consists of a liquid part (hyaloplasm, or matrix), organelles and inclusions.

Hereditary apparatus: one large "naked", devoid of protective proteins, DNA molecule, closed in a ring - nucleoid. In the hyaloplasm of some bacteria there are also short circular DNA molecules that are not associated with a chromosome or nucleoid - plasmids.

There are few membrane organelles in prokaryotic cells. There are mesosomes - internal outgrowths of the plasma membrane, which are considered the functional equivalents of eukaryotic mitochondria. In autotrophic prokaryotes, lamellae and lamelosomes are found - photosynthetic membranes. They contain the pigments chlorophyll and phycocyanin.

Some bacteria have organelles of movement - flagella. Bacteria have recognition organelles - pili (fimbriae).

Chromatin in the form of clumps is scattered in the nucleoplasm and is an interphase form of the existence of chromosomes.

AT plant cells There are also chloroplasts in which photosynthesis takes place.

Functions and structure of the cytoplasmic membrane and cell nucleus

The elementary membrane consists of a bilayer of lipids in complex with proteins. Each fat molecule has a polar hydrophilic head and a non-polar hydrophobic tail. In this case, the molecules are oriented so that the heads are turned outward and inside the cell, and the non-polar tails are turned inside the membrane itself. This achieves selective permeability for substances entering the cell.

Functions of membrane proteins: receptor, structural, enzymatic, transport

1) barrier (delimitation of the internal contents of the cell);

2) structural (giving a certain shape to cells);

3) protective (due to selective permeability);

4) regulatory (regulation of selective permeability for various substances);

5) adhesive function (all cells are interconnected through specific contacts (dense and loose);

6) receptor;

The cell nucleus consists of a membrane, nuclear sap, nucleolus and chromatin. . nuclear envelope consists of two membranes. The main functions of the nuclear envelope are the separation of genetic material (chromosomes) from the cytoplasm, as well as the regulation of bilateral relationships between the nucleus and the cytoplasm.

The nuclear envelope is permeated with pores that have a diameter of about 90 nm.

The basis of nuclear juice (matrix, nucleoplasm) is proteins. Juice forms the internal environment of the nucleus, plays an important role in the work of the genetic material of cells.

nucleolus is the structure where the formation and maturation of ribosomal RNA (r-RNA) takes place. The rRNA genes occupy certain regions of several chromosomes, where nucleolar organizers are formed, in the region of which the nucleoli themselves are formed.

Chromatin consists mainly of DNA strands (40% of the mass of the chromosome) and proteins (about 60%), which together form the nucleoprotein complex.

8. Structure and functions of mitochondria and lysosomes

Mitochondria- these are permanent membrane organelles of a round or rod-shaped (often branching) shape. The main functions of mitochondria:

1) play the role of energy stations of cells;

2) store hereditary material in the form of mitochondrial DNA.

Mitochondria have two membranes: outer (smooth) and inner (forming outgrowths - leaf-shaped (cristae) and tubular (tubules)).

Lysosomes- These are bubbles with a diameter of 200-400 microns. (usually). They have a single membrane. The main function is intracellular digestion of various chemical compounds and cellular structures.

Endoplasmic reticulum (EPS)- a system of communicating or separate tubular channels and flattened cisterns located throughout the cytoplasm of the cell. EPS channels can connect with surface or nuclear membranes, contact with the Golgi complex. Rough XPS On the channels of the rough ER, ribosomes are located in the form of polysomes. This is where protein synthesis takes place. Smooth EPS There are no ribosomes on smooth ER membranes. Here, mainly the synthesis of fats and similar substances (for example, steroid hormones), as well as carbohydrates, proceeds. Through the channels of smooth EPS, the finished material also moves to the place of its packaging into granules (to the zone of the Golgi complex). Golgi complex gives rise to primary lysosomes.

10. Structure and functions of non-membrane cell structures

Ribosome It is a rounded ribonucleoprotein particle. Its diameter is 20-30 nm. The ribosome consists of large and small subunits. The cells of all animals, some fungi, algae, higher plants are characterized by the presence of a cell center. Cell Center usually located near the nucleus. It consists of two centrioles located mutually perpendicular. From the centrioles of the cell center, division spindle threads are formed during cell division. cytoplasm. It consists of a liquid part - hyaloplasm (matrix), organelles and cytoplasmic inclusions. Hyaloplasm- the main substance of the cytoplasm. Inclusions are relatively non-permanent components of the cytoplasm. There are: 1) reserve nutrients that are used by the cell itself during periods of insufficient intake of nutrients from the outside; 2) products that are to be released from the cell;

Many viruses are the causative agents of diseases such as AIDS, rubella measles, mumps (mumps), chickenpox and smallpox. Mature viral particles are called virions. In fact, they are a genome covered with a protein coat on top. This shell is the capsid.

Gametes Egg- a large, immobile cell that has a supply of nutrients. The size of the female egg is 150-170 microns Sperm is the male sex cell (gamete). He has the ability to move. The dimensions of the spermatozoon are microscopic: the length of this cell in humans is 50-70 microns

The spermatozoon has a head, neck, intermediate section and tail in the form of a flagellum. Almost the entire head is filled with the nucleus, which carries the hereditary material in the form of chromatin. At the anterior end of the head (at its top) is the acrosome, which is a modified Golgi complex.

Fertilization is the process of fusion of sex cells. As a result of fertilization, a diploid cell is formed - a zygote,. Biological role asexual reproduction Maintaining fitness enhances the importance of stabilizing natural selection; provides fast reproduction rates; used in practical selection. Forms of asexual reproduction

In unicellular organisms, the following forms of asexual reproduction are distinguished: division, endogony, schizogony and budding, sporulation.

Division typical for amoeba, ciliates, flagella. First, the mitotic division of the nucleus occurs, then the cytoplasm is divided in half by an ever deeper constriction. In this case, daughter cells receive approximately the same amount of cytoplasm and organelles.

Endogony(internal budding) is characteristic of Toxoplasma. With the formation of two daughter individuals, the mother gives only two descendants. But there may be internal multiple budding, leading to schizogony.

It occurs in sporozoans (malarial plasmodium), etc. There is a multiple division of the nucleus without cytokinesis. From one cell, a lot of daughters are formed.

budding(in bacteria, yeast fungi, etc.).

sporulation(in higher spore plants: mosses, ferns, club mosses, horsetails, algae).. Vegetative a form of reproduction by part of the mother's organism.

regeneration- restoration of lost tissues and body parts (in annelids, lizards, salamanders). Sexual reproduction - fertilization, Parthenogenesis - daughter organisms develop from unfertilized eggs. The meaning of parthenogenesis:

1) reproduction is possible with rare contacts of individuals of different sexes; 2) the population size increases sharply; 3) occurs in populations with high mortality during one season.

Cell division. Phases of mitosis:

1) prophase. The centrioles of the cell center divide and diverge to opposite poles of the cell. From microtubules, a spindle is formed, which connects the centrioles of different poles. At the beginning of prophase, the nucleus and nucleoli are still visible in the cell; by the end of this phase, the nuclear envelope is divided into separate fragments. The condensation of chromosomes begins: they twist, thicken, become visible in a light microscope. In the cytoplasm, the number of structures of rough EPS decreases, the number of polysomes sharply decreases;

2) metaphase. The formation of the fission spindle is completed. The condensed chromosomes line up along the equator of the cell, forming the metaphase plate. Spindle microtubules attach to the centromeres, or kinetochores (primary constrictions), of each chromosome. After that, each chromosome splits longitudinally into two chromatids (daughter chromosomes), which are connected only in the centromere region;

3) anaphase. The connection between the daughter chromosomes is broken, and they begin to move to opposite poles of the cell. At the end of anaphase, each pole contains a diploid set of chromosomes. Chromosomes begin to decondense and unwind, become thinner and longer;

4) telophase. Chromosomes are completely despiralized, the structure of the nucleoli and the interphase nucleus is restored, and the nuclear membrane is mounted. The spindle of division is destroyed. Cytokinesis (division of the cytoplasm) occurs. The formation begins in the equatorial plane of the constriction, which completely divides the mother cell into two daughter cells.

1. Amitosis is direct nuclear fission. At the same time, the morphology of the nucleus is preserved, the nucleolus and the nuclear membrane are visible. Chromosomes are not visible, and their uniform distribution does not occur. The nucleus is divided into two relatively equal parts without the formation of a mitotic apparatus. Meiosis is a type of cell division in which the number of chromosomes is halved and meiosis stages The first division of meiosis (reduction) leads to the formation of haploid cells from diploid cells. In prophase I, as in mitosis, chromosomes spiralize. At the same time, homologous chromosomes approach each other with their identical sections (conjugate), forming bivalents. Before entering meiosis, each chromosome has doubled genetic material and consists of two chromatids, so the bivalent contains 4 strands of DNA. In the process of further spiralization, crossing over can occur - the crossing of homologous chromosomes, accompanied by the exchange of the corresponding sections between their chromatids. In metaphase I, the formation of the division spindle is completed, the threads of which are attached to the centromeres of chromosomes combined into bivalents in such a way that only one thread goes from each centromere to one of the poles of the cell. In anaphase I, the chromosomes move to the poles of the cell, with each pole having a haploid set of chromosomes consisting of two chromatids. In telophase I, the nuclear envelope is restored, after which the mother cell divides into two daughter cells.

The second division of meiosis begins immediately after the first and is similar to mitosis, but the cells entering it carry a haploid set of chromosomes. Prophase II is very short in time. It is followed by metaphase II, while the chromosomes are located in the equatorial plane, a division spindle is formed. In anaphase II, the centromeres separate, and each chromatid becomes an independent chromosome. Daughter chromosomes separated from each other are sent to the division poles. In body phase II, cell division occurs, in which 4 daughter haploid cells are formed from two haploid cells.

Thus, as a result of meiosis, four cells with a haploid set of chromosomes are formed from one diploid cell. The biological significance of meiosis 1) is the main stage of gametogenesis; 2) ensures the transfer of genetic information from organism to organism during sexual reproduction; 3) daughter cells are not genetically identical to the between themselves. Gametogenesis is the process of formation of germ cells. Ontogenesis- this is the process of individual development of an individual from the moment of formation of a zygote during sexual reproduction until the end of life. The first stage of embryonic development - splitting up. At the same time, first 2 cells are formed from the zygote by mitotic division, then 4, 8, etc. The resulting cells are called blastomeres, and the embryo at this stage of development is called the blastula. At the same time, the total mass and volume almost do not increase, gastrulation. At this time, the blastomeres, which continue to rapidly divide, acquire motor activity and move relative to each other, forming layers of cells - the germ layers from the ectoderm develop the skin and its derivatives. The endoderm gives rise to the organs of the respiratory and digestive systems. Muscle, cartilaginous and bone tissue, organs of the circulatory and excretory systems are formed from the mesoderm.

Dissimilation, or energetic exchange is a set of cleavage reactions of macromolecular compounds, which are accompanied by the release and storage of energy.
Stage 1 Preparatory:
occurs in lysosomes or in food. The system breaks down complex organic substances into simpler ones.
(e.g. proteins to amino acids)
ATP is not synthesized at this stage
Stage 2 Anoxic (glycolysis):
takes place in the cytoplasm
glucose up to 2 molecules of pyruvic acid
energy storage in the form of 2 ATP molecules

3 Stage Oxygen:
happens in mitochondria
oxidation of pyruvic acid to CO2 and H2O
36 mol of ATP is formed

The OGE is a mechanism that allows you to determine the degree of learned material, as well as the ability to use it. This certification is carried out after the 9th grade.

OGE in biology is not mandatory, therefore it is mainly chosen by students aimed at studying in specialized classes in grades 10-11. It is also a subject of choice for those who are going to enter humanitarian universities of the relevant direction, namely: future biologists, psychologists, chemists, geographers, doctors, athletes and rehabilitation specialists. In addition, the result affects the overall score of the certificate that students receive, which partly determines their future fate upon admission.

The success of passing the OGE in biology is important not only for schoolchildren: it is also an indicator of the capabilities of teachers in a particular educational institution and allows you to collect statistics on the degree of assimilation of the program in this discipline in a particular school, city, district or region.

Federal Institute pedagogical measurements(FIPI), as the body responsible for the preparation and organization of the OGE in all subjects, including biology, officially announced that there will be no fundamental changes in the structure and form of passing the OGE in 2018.

The exam will last for 3 hours, during which the examinee must have time to cope with the maximum number of tasks.

Unlike other items, it is forbidden to use any auxiliary materials during the allotted time. The Ministry of Education and Science of the Russian Federation also imposes a strict taboo on the use of smartphones or smartwatches as information carriers.

The dates during which the OGE in biology will be held in 2018 are:

• Early testing - 23.04. Reserve day for preliminary delivery - 3.05.
• The general day for the OGE in biology is May 31. Reserve period - 18.06.
• Additional testing is scheduled for 10.09. Additional reserve will take place on 18.09. - the last date for those wishing to take the general state exam in biology.

Structure of KIM

The basis for conducting the OGE is KIM - control and measuring material, divided into such blocks:

1. Concerning directly the foundations of biology as a science. Includes tasks on the role of biology for understanding natural processes, on the practical application of this knowledge and areas of its use. In addition, this block contains questions on the knowledge of experimental techniques and methods of studying wildlife.
2. Living organisms. These questions concern the structure and functions of organisms, types of tissues and cells, organs and organelles. This also includes tasks on genetic laws, methods of reproduction and distribution of all kingdoms of wildlife.
3. Evolutionary processes and diversity of life forms. This section contains questions to test knowledge on the classification and diversity of wildlife, on evolutionary issues and the variability of species diversity.
4. Human biology. This section of questions includes the anatomical and physiological foundations, origins, hygiene, and the foundations of human health.
5. Fundamentals of interaction between living organisms and their associations, as well as with external conditions, the relationship between different species and types of formation of food chains.

The profile commission involved in the preparation of tickets for the OGE in biology in 2018 reported that KIM meets all the requirements, fully reflects all areas of knowledge and is able to fully reflect the level of the student's preparation. For this reason, there will be no changes to tickets or task structure.

As before, the questions of the program from grades 5 to 9 of the biology course will be presented in the tickets.

In total, the ticket will contain 32 tasks. Structurally, they are all divided into two parts, designed for different types answers.

• Part 1. It contains 28 tasks that resemble the test principle. 22 basic questions imply an answer, in the form of a number or phrase, standing next to the desired answer. The next 6 tasks require a deeper knowledge of the subject.
• Part 2. 4 tasks that require a longer study. In the first question, the answer must include a text reflection of the required information. One task involves testing the analytical grouping ability of material presented in a tabular format. 2 recent assignments aimed at the practical application of theoretical knowledge.

Despite the fact that there are much fewer tasks in the second part, but in terms of time, both parts require approximately the same time for a thorough study.

How is work evaluated?

After a full check, the work is assigned a certain score, which means a specific assessment.

To understand what assessment the scores correspond to, you can use the following scale:

• 0-12 - "2";
• 13-25 - "3";
• 26-36 - "4";
• 37-46 - "5".

To understand the OGE grading system, you need to know the principle of scoring:

• the correct answer of tasks No. 1-22 brings the student 1 point each;
• starting with #23 and ending with #27, the correct answer brings 2 points each. 1 point is lost if the answer contains more than one answer, and one of them is incorrect;
• a full answer to question No. 28 adds 3 points, and in case of partial fulfillment - 2 or 1 point in proportion to the fulfillment;
• the maximum number of points for the second part of the ticket (No. 29-32) corresponds to 11.

Preparation for the OGE

Schoolchildren who intend to connect their lives with biology, or who simply care about improving academic performance in the certificate, tend to start preparing for the OGE in advance.

Preparation may include the following steps:

• Self preparation. This allows you to work through the program of all years of study at home and completely free of charge. When self-preparation, it is advisable to go from simpler topics to more complex ones.
• Online training. Many sites offer this option. Some of them are free, while others provide paid services. Such lessons contain a lot of visual information, video lessons, diagrams and tabular materials. The online programs also include a pre-test of knowledge, which helps to identify problematic topics and types of questions.
• Working with a tutor or at specialized courses preparing for the passing of the OGE.

The base during the preparation is the tasks of past years, since there have been no fundamental changes recently.

Challenging the results

If you disagree with the assessment obtained from the result of the OGE in biology, you can appeal to the municipal education authority, where conflict commissions are created specifically for such cases.

An appeal can be filed by the student himself or his parents. This must happen within 2 working days after the announcement of the results. 4 working days are allotted for consideration of the complaint (only Sunday is excluded). The work is re-viewed and evaluated by the conflict commission.

Video Tips for self-training:

For all 9th ​​grade graduates who want to successfully move to the next level, the question arises, how to prepare for the GIA? Preparing for the GIA in biology on your own or with a tutor is an individual choice for everyone, however, it should be remembered that preparing on your own is fraught with a number of difficulties.

Preparation for the GIA in biology on your own

One of the most effective methods self-preparation for the GIA (OGE) in biology or mathematics can be called the passage of special tests. It's not enough to decide test tasks. They need to be able to pass for a strictly limited time period. Therefore, it is very important to learn in advance how to control the time to complete each test.

To do this, you must adhere to the following recommendations:

1. It is important to allocate time correctly - there should always be a reserve for solving problems of increased complexity.
2. It is necessary to objectively assess the difficulty of tasks and choose the priority of their solution, taking into account this factor.
3. You need to constantly compare your results with the correct answers to analyze your mistakes.
4. It is necessary to use the method of spiral movement on tests.

Preparation for the GIA / OGE with the help of multimedia aids

Self-preparation for the GIA (OGE) in biology or mathematics is possible using various multimedia material. Using information technology, students perceive, assimilate and consolidate the material faster than using other methods. This effect is due to a combination of sounds, images and interactivity, and due to the feedback system, operational control and qualitative assessment of knowledge are carried out. The structure of electronic textbooks makes it easy to move from one course to another.

The advantages of using multimedia technologies lie in the increased quality of education due to the interest of students in computer systems and the unusual format of lessons.

Ready-made electronic products for preparing for the GIA (OGE) in biology or mathematics makes it possible to make the process as rich and interesting as possible. Training provides:

• reflection of essential aspects of biological objects;
• implementation of the visualization method;
• priority consideration of the characteristics of biological objects and natural phenomena most frequently encountered in examination tests.

Cons of multimedia learning on your own

It is difficult to independently select an electronic manual that will enable the student to obtain all the necessary information. With the use of most of them, it is impossible to effectively repeat the theoretical material of all sections of biology or mathematics textbooks, consolidate knowledge, conduct self-control and objective self-assessment of knowledge by passing the test tasks provided for by the GIA (OGE).

Theoretical materials often contain information that is unnecessary for preparing for exams, and therefore students will have to independently determine which materials are important and which are not. At the same time, the test tasks offered in electronic textbooks may not coincide in form and content with the tests of the state final certification.

Preparing with a tutor

The downside of school education is that during the time allotted for lessons, teachers do not have time to provide their students with all the necessary information that is required for successful exams. It is difficult to master it on your own, even if the subject is interesting to the graduate. In this case, biology tutors come to the rescue, thanks to which graduates can easily fill knowledge gaps.

Benefits of tutoring:

• individual approach;
• all attention is directed to only one student;
• the opportunity to learn and consolidate a large amount of knowledge in a short time.

You can also prepare for exams directly at educational institutions in which students plan to continue their education. Most of them advertise their courses by placing a "Getting Ready for the GIA" stand.

However, often before exams, students do not have time to travel to tutors, due to heavy workload.

Preparation for the GIA in biology online will help solve this problem. Now this opportunity is available to everyone, since progress has affected the modernization of the education process - classical training with teachers has successfully replaced distance learning. The Internet allows you to study with teachers from all over the world while staying at home.

On our service you can find a tutor in biology, mathematics, physics, chemistry, geography and a number of other disciplines who are ready to help at any time of the day.

The undeniable advantages of such a resource are the ability to:

• learning at home;
• selection of the best teacher by viewing and analyzing profiles on the site;
• fast mastering of the most difficult material;
• low cost of classes;
• high quality lessons, due to which graduates will be able to successfully pass the exam.

At the same time, in order to ask an urgent question, the student does not need to personally meet with the teacher - he can easily do this via the Internet.

Specialized hens in preparation for the GIA

Preparation for the GIA in biology with the help of elective courses

Elective biology courses for 9th grade graduates using information technologies provide:

• training with the help of various visual materials, such as videos, slide presentations, animations, photographs, diagrams and tables, online books accompanying the theoretical part of the subject and helping to consolidate the information received;
• repetition of the theory in electronic format, necessary for passing the GIA, and independent study of materials;
• passing tests and various tasks that were compiled in accordance with the control and measuring materials of the state final certification in biology for the current year;
• conducting self-control in all sections of the school biology course;
• the use of a differentiated approach to students, which involves taking into account their ability to learn, by repeating the school course from the elementary level.

Plan for preparation for the GIA (OGE) in biology remotely for graduates of grade 9

Graduates of the 9th grade have the opportunity to get prepared from scratch for the GIA in biology with a repetition of all the necessary sections of the subject.

The main topics for preparation involve repetition:

1. Biology, as a science, is the study of the basic methods of biology and the properties of living organisms.
2. Kingdoms of Bacteria, Fungi, Plants and Animals.
3. Similarities between humans and animals.
4. Neurohumoral regulation of vital processes of the body;
5. musculoskeletal system;
6. circulatory and lymphatic systems.
7. Systems of digestion, respiration, metabolism, excretion of products of substances.
8. Reproduction and development of the human body.
9. Psychology and human behavior.
10. infectious diseases.
11. Teachings about the biosphere.

Specialized courses for online preparation

You can prepare for the GIA / Unified State Examination in biology online without leaving your home by completing specialized Foxford courses on the website http://foxford.ru/ or Lancman school- http://school-lancman.ru/. Teachers from leading Russian universities will give everything necessary knowledge for the successful passing of exams or preparation for the Olympiads.

The Foxford course involves a complete immersion in school curriculum, after which the majority of schoolchildren pass exams an order of magnitude better than their peers. With their help, students can improve their knowledge of biology, if it is a problematic subject for them, and thereby significantly improve their academic performance. At the same time, it enables schoolchildren who love biology to understand it even better and take first places in city olympiads or enter specialized universities in the country for budget places. Chairpersons, jury members and Olympiad coaches help to achieve such results faster.

In order to evaluate the effectiveness of the courses, you can take one free lesson.

Description of Foxford courses

Benefits of Foxford Courses

• conducting training by the best teachers of the Moscow Institute of Physics and Technology, Moscow State University and other universities, members of the jury of competitions, authors of textbooks in biology;
• online classes in real time;
• consolidation of the material by completing homework with suggestive tips;
• using an interactive tutorial;
• the ability to view videos of past classes;
• monitoring the effectiveness of academic performance by setting an objective assessment for the knowledge of each subsection of biology;
• a high level of comfort due to access to classes at any convenient time and a cozy workplace at the computer;
• the possibility of paying tuition in installments.

Frequently asked Questions

1. How are classes conducted? - Classes are held on the website http://foxford.ru/ in real time. The student sees a tutor on the screen, leading a lesson near the blackboard. You can ask him a question at any time by text or voice chat.
2. How to join the lessons? - All classes are held according to a strict schedule, and you can connect to them one hour before they start. Anyone who has paid access to courses can do this by clicking on the “Connect” button.
3. How to do homework? - At the end of each lesson, the student has access to homework and abstracts on topics already studied. During their implementation, students can use interactive tips, refer to notes and records of past classes.
4. How to become the best student in the courses? - For completing tasks, all students receive a certain score, the value of which is affected by their complexity and the number of hints used.
5. What should I do if I didn't manage to connect in time? - Those who joined the lesson later than the due date can watch the missed lessons in the video recordings.

Getting ready for the GIA with Lancman school

teachers educational center Lancman school have vast experience in preparing graduates for passing the exam or GIA, both in biology and in all other school subjects, participation in olympiads and admission to a university. Training is conducted in groups of up to 6 people using video lessons.

Benefits of courses at Lancman school

1. Work for results. One group consists of no more than six people, which allows the teacher to give maximum attention to each of them.
2. Level up. Group members, on average, score 37 points higher on exam tests than their classmates.
3. Preparation for the exam in all subjects.
4. Trial lesson is free.
5. Effective training program.
6. Convenient class schedule, based on the needs of students.
7. Monitoring of knowledge by trial EGE monthly.

Conclusion

Summing up, it should be noted that if students prepare for exams on their own, they may encounter a number of difficulties. Screening important information from superfluous, choosing the right allowance, exercising self-control - for most schoolchildren, things are quite difficult. Classical lessons with a tutor are more effective, because the teacher pays maximum attention to the student and uses an individual approach for his learning. However, the lack of time to travel to tutors often makes you abandon this method. The most effective and convenient way is thematic training in specialized online courses with the help of the best teachers in the country. This type of training provides a unique opportunity to prepare for top-level exams while sitting in a comfortable chair in front of a computer, saving time and money. At the same time, the student can choose the schedule of classes that will be most convenient for him, and in case of missing a lesson, view it in the video.

How to independently prepare for the OGE in biology for graduates of secondary educational institutions fast and efficient? Now these questions are puzzled by everyone who has to take exams, on the result of which the future depends.

Quite often, students cannot decide future profession. And this means that difficulties arise with the choice of subjects, since technical schools, colleges and schools require the delivery of certain subjects for the desired specialty. Students who stay at the school must also pass the subjects for the transition to 10th grade. The Russian language and mathematics are considered mandatory, and the rest are optional. So, if you have chosen biology, then it is possible to prepare in a short time. First of all, you need to take all the books on the subject for previous years. And even better - collect notebooks with notes. So it will be faster and easier to learn the material. If there are no abstracts, then it does not matter! You can start a notebook, and already write down important things there.

After all the material has been completed, you can proceed to the second stage of preparation.

The most important thing in preparing for exams is a great desire. If not, then there will be no result. Then you need to determine for yourself which method of preparation will be best.

At the moment, special courses are leading. They are arranged in the colleges or universities themselves. 3-4 groups of 15-20 people are recruited. This is suitable for those who know the subject for a weak four. It is worth noting that in group classes you can miss important material. There are a lot of people, and it will be physically difficult for the teacher to approach everyone. So you have to listen carefully. There are some advantages here as well. For example, in a group there may be those students who have learned some material well and will be able to explain later.

Every second hires tutors. This is the same teacher, only engaged in an individual order. You don't have to go through all the topics. You can take those that are incomprehensible. Or download the OGE program. And already understand it.

Self-education is the most effective method. Here the student reads himself, chooses what is useful for himself, learns the most important things and memorizes what will be useful in the exams. Only this is a way for those who have great willpower and no laziness. You will have to allocate your time so that you have time for classes. You need to allocate at least 2 hours a day for self-study. Otherwise, there will be no result.

Which preparation method to choose?

Now it is very fashionable to impose on graduates training courses and tutors. Such methods are very costly. Sometimes like this additional education a lot of money goes. And there are parents who go into debt to educate their children. There is another way out - self-preparation. Firstly, it gives more knowledge, and secondly, it does not require investments.

The best option is to start preparing for exams after finishing grade 8 in the summer. But if it was not possible, then it is desirable to put the plan into practice in September. In order not to miss anything, you should prescribe an algorithm of actions for yourself:

1. Before you prepare for the test, you must take all the books, reference books, encyclopedias on biology. If the librarian refuses to give textbooks, then you must say what you need to prepare for exams. Then you should purchase a notebook and make notes on important topics. This will take about three months. Then you need to search the Internet for tables, additional electronic textbooks, a brief theory. If possible, print it out so that the material is always in front of your eyes. When there is a main base (it needs to be mastered from September to December), you can proceed to solve the OGE.
2. Now there are many sites for solving the OGE online. This is convenient, because you can go in at any time, select an option and decide. Online tests have time, a system for counting correct and incorrect answers, as well as a total score. So immediately after the decision, you can evaluate your knowledge. Do not be upset if the system showed a low level of preparation for the first time. On the contrary, you need to start exercising intensely. If the specified time is not enough, then you can print tests or buy at a bookstore. In this case, you can already sit and think as much as you want.
3. Annually the program of the main state exam is changing. Or are there amendments. Therefore, it is very important to download a program that indicates which topics to pay special attention to. And it is better to take it from a tutor or biology teacher. They certainly have it right!
4. After all the books have been read, more than 80 tests have been passed, you should contact the teacher with a request to check your knowledge. This is best done in March. If the teacher says that the result is excellent, then you need to continue in the same spirit. For general development you can take additional literature on biology, which can also become an integral source of information.
5. In the social network Vkontakte, special communities have been created to prepare for exams. There are several thousand schoolchildren from different parts of Russia. And this is another source of information.
6. If there are those in the class who pass biology, then you can prepare with them. As the saying goes: "One head is good, but two is better."

In self-preparation, in no case should you give yourself slack. It is recommended to practice daily for 3 hours on weekdays and up to 5 hours on weekends. Of course, it's hard to sit for so long. Therefore, during the period of training, you need to take a short rest for 10-15 minutes.

Apart from schooling and preparation, there are additional things - this is cleaning, walking in the fresh air, entertainment. If possible, it is better to download an audio recording of the topics and listen to them in your free time or before going to bed.

It is necessary to prepare for the GIA in biology carefully, using all kinds of sources of information. And the usual lessons in this subject at school cannot be missed, despite the fact that the topic is familiar and simple. Repetition has never done anyone any harm.

The OGE program will definitely include the following topics:

• Biology as a science;
• Living organisms;
• Anatomy;
• Botany;
• Zoology;
• Genetics;
• Bacteria and viruses;
• Animal Kingdom;
• human physiology;
• The evolution of the animal world;
• Biosphere;
• Ecosystem etc.

And that's not even half the list! Good preparation takes 4 months or more. Cramming, spurs and hope for luck are unlikely to help. Only knowledge and the ability to apply them in practice will give a positive result.

How to prepare for exams and how difficult it is, is understandable. How to make it easier is not clear. Doctors strongly recommend the use of Glycine, Motherwort Tincture, Piracetam and other sedatives. And in order to find out whether this or that medicine is suitable, you need to consult a specialist. The main thing in this question is not to panic. It is especially important to go out into the fresh air and eat right.

Preparing for exams takes a lot of time and effort. In order to pass the subject to a good mark, you have to try. If possible, do not postpone classes in the background. After all, his future depends on how the child prepares. Even if there is only a month left before the exam, do not panic. There is nothing impossible in the world!