Preparation of OGE in biology theory. Preparation for the OGE in biology. Biology as a science. Methods of biology: theory and practice

Block 3. System, diversity and evolution of living nature

Animal Kingdom

TYPE CHORDATES. SUPERCLASS FISH

Fish are the largest group of vertebrates. Fish are divided into the class Cartilaginous fish (sharks, rays ) and class Bony fishes (sturgeon, salmon, herring, crucian carp, pike, swordtail and etc.). The main criterion for this division is the substance of which the internal skeleton of fish consists:cartilage or bone.

Animals of this, the most thriving group of vertebrates today, can be found in all corners of our planet - from the North Pole to the South. They are found both in brackish waters of seas and oceans, and in fresh waters of lakes and rivers; They live in the dark depths of ocean basins and in sun-drenched coral reefs. The number of their forms is countless, 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 of fish

Fish are vertebrates that live in water (an environment much denser than air). The fish's body is remarkably adapted to perform all vital functions in 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 hard skeleton, muscles, skin, digestive, circulatory and nervous systems, respiratory, excretory and reproductive 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 in them depends on the temperature of the water.

Today, about 25 thousand species of fish are known.

Habitats and external structure of fish

The habitat of fish is various bodies of water on our planet: oceans, seas, rivers, lakes, ponds. It is very vast: 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 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 characteristics.

General plan of the external structure of fish

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

The outside of the body is covered with skin. Protects mucus-coated skin of most fishscales .

The locomotion organs of fish arefins . Fins are outgrowths of skin resting on bones.fin rays . The caudal fin is of greatest importance. On the lower sides of the body there are paired fins: pectoral and ventral. They correspond to the fore and hind limbs of terrestrial vertebrates. The position of paired fins varies among different fish. The dorsal fin is located on top of the fish’s body, 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 there is a kind of organ that senses the flow of water. Thislateral line . Thanks to the lateral line, even blinded fish do not bump into obstacles and are 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 approach. The lateral line may be intermittent, continuous, or completely absent.

Functions of fins

Thanks to fins, fish are 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 located in the dorsal part.

Unpaired fins (dorsal and anal) provide stability to the body. The caudal fin in the vast majority of fish performs the function of propulsion.

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

Body Shape

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

Coverings of the body

On the outside, the skin of fish is covered with scales - thin translucent plates. The scales overlap each other with their ends, 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 varies: from microscopic toblackheads 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 space and the color of the body becomes bright. If the chromatophores contract, the pigment grains accumulate in the center, leaving most of the cell uncolored, and the body color fades. If pigment grains of all colors are evenly distributed inside the chromatophores, the fish is brightly colored; if pigment grains are collected in the centers of cells, the fish becomes almost colorless and transparent; if only yellow pigment grains are distributed among their chromatophores, the fish changes color to light yellow.

Chromatophores determine the diversity of fish colors, which are especially bright in the tropics. Thus, fish skin 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 the temperature and chemical composition of water.

Features of the internal structure and vital functions 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 the canal in which the spinal cord lies. The arches protect him from injury. Long ones stick out from the archesspinous processes . The lower arches in the body part are open. Adjacent to the lateral processes of the vertebraeribs – they cover the internal organs and serve as a support for the trunkmuscles . Particularly powerful muscles are located in fish in the back and tail. In the tail, the lower arches of the vertebrae form a canal through which blood vessels pass.

The skeleton also includes bones and bony raysdoubles And unpaired fins . The skeleton of unpaired fins consists of many elongated bones embedded 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. There is a single bone in the abdominal girdle. The skeleton of the free pelvic fin consists of many long bones.

In the skeleton of the head a smallscull, or skull . The bones of the skull protect the brain. The main part of the skeleton of the head consists of the upper and lower jaws, the bones of the eye sockets and the gill apparatus. Large ones are clearly visible in the gill apparatus.gill covers . If you lift them up you can seegill arches – they are paired: left and right. Gills are located on the gill arches. There are few muscles in the head; 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 through their work. The main muscles are located evenly in the dorsal part of the fish's body; The muscles that move the tail are especially well developed.

The musculoskeletal system performs different functions in the body. It serves as a support, allows movement, and 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. Are there small or largeteeth . Behind the oral cavity is the pharyngeal cavity. It shows gill slits separated by interbranchial septa. They have gills on them. They are covered by gill covers from the outside. Next comes the esophagus and a voluminous stomach. Behind the stomach is the intestine. In the stomach and intestines, food is digested under the influence of digestive juices: in the stomach there is gastric juice, in the intestine there are 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 the necessary 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 bladder with air, the newborn fry floats to the surface of the water and swallows air into the esophagus. Later, the connection between the swim bladder and the esophagus is interrupted.

Interestingly, with the help of a swim bladder, some fish are able to amplify the sounds they make. Some species of fish do not have this organ (for example, those living on the bottom or those 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 similar 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 mass of the fish comes into balance with the buoyant force acting on the fish at a certain depth.

Respiratory system located in the pharynx area.

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

Circulatory system fish schematically represents a closed circle consisting of vessels. Its main organ is the heart. Ittwo-chamber: comprises atria And ventricle . The work of the heart ensures blood circulation. Moving through the vessels, blood carries out gas exchange, transport 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 cells, is saturated with carbon dioxide, i.e. it becomesvenous , and returns to the heart. In all vertebrates, the vessels that extend from the heart arearteries . The vessels that lead to the heart areveins .

Excretory organs filter water and metabolic waste products from the blood and remove them from the body. Excretory organs are presented in pairskidneys located along the spine,and ureters . Some fish have a bladder.

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

Metabolism – a set of chemical processes occurring in a living organism . Metabolism is based on two phenomena: the construction and breakdown of organic substances. Complex organic substances that enter the body with food are transformed into less complex ones during digestion. 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 uses energy that is released during breathing. At the same time, many substances in cells break down into water, carbon dioxide and urea. Thus,metabolism consists of processes of construction and breakdown of substances .

The metabolic rate of fish depends on body temperature. Fish are animals with variable body temperatures - cold-blooded. The body temperature of fish is close to the ambient temperature and does not exceed it by more than 0.5–1.0 degrees (although in tuna fish 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 brain, spinal cord (central nervous system) and nerves extending from them (peripheral nervous system).Brain consists of five departments:front , including the optic lobes,middle, intermediate, cerebellum And oblong brain. All active pelagic fish have large optic lobes and cerebellum because 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 irritations. This reaction is calledreflex . The behavior of fish showsunconditional 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 are developed during the life of each fish. For example, by tapping on the glass of the aquarium every time during feeding, you can ensure that the fish begin to gather near the feeder only when knocking.

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

Perceives the direction and strength of water flowlateral line . It is formed by a channel running inside the body, which communicates with the aquatic environment through holes in the scales. Sensitive cells in the lateral line respond to changes in water pressure and transmit signals to the brain.

Features of fish reproduction and development

Reproductive organs . Almost all fish dioecious . For reproduction, special paired organs are used: in males -testes (milt), vas deferens, in females -ovaries , oviducts. Male germ cells - sperm - develop in the testes, and female germ cells - eggs (eggs) - develop in the ovaries. There is a special genital opening for their removal. In some fish species, 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 striking example of sexual dimorphism is the extremely peculiar appearance of males and females of some deep-sea fish -anglerfish .

Small males, only a few centimeters in size, are attached to the body of much larger females. Or rather, they grow, because in this case their circulatory system becomes an appendage of the female’s circulatory system. From this moment on, males become incapable of independent existence. They are needed only for the production of offspring.

Reproduction and development of fish. When the reproductive cells mature, the reproductive instinct appears in fish. Fish reproduction is calledspawning . Readiness for spawning is signaled by the behavior of the fish and its nuptial coloration. Some fish spawnmigration , moving to places more suitable for the development of their future offspring.Salmon, eels and a number of other fish overcome enormous distances.

Spawning females lay eggs, which are fertilized by the males. Fish lay eggs on accumulations of algae, lumps of mucus, foam bubbles at the surface of the water, in holes at the bottom, etc. External fertilization - occurs in the environment.

When sex cells fuse, an egg is formed, which matures in water. An embryo develops inside the egg. A mature fish embryo is freed from its shell, enters the water and from that moment is called a larva. Over time, the larva begins to independently feed on microscopic algae, ciliates, and then small crustaceans. If it survives, it becomes similar to an adult fish, it is calledlittle boy .

In many species of fish, enormous fertility is an adaptation to 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 eggs. However, these fish take care of their offspring. For example,three-spined stickleback lays only 60–70 eggs. Caring for offspring takes place in a special wayseahorses, pipefish, tilapia . There are also viviparous fish species. During a live birth, the number of cubs born 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 move on to “adult” life and enter the feeding period. Having reached sexual maturity, 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 , like spawning migrations (salmon, sturgeon, freshwater eel ), caring for offspring (three-spined stickleback, seahorse etc.), mating “dances”. All of these are adaptations of species to living conditions and survival next to other species of organisms.

Migrations. As we found out, fish go through the following stages during their life cycle: egg, larva, fry, feeding, mature individual. In 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) are spent by salmon in rivers. Then the time comes for the first migration, and the young salmon slide down the rivers into the sea. Here, moving and feeding over a wide area, salmon quickly develop (feed) and reach sexual maturity.

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

Eel migrations. Lives in the rivers of EuropeEuropean river eel . Eels can reach 2 m in length and 6 kg in weight. The river eel is a migratory fish. In the river eel, the juvenile stage, spawning migration and spawning take place in the sea, and growth and feeding take place in fresh water. The eel can stay for a long time in its main habitats - quiet river backwaters. At the onset of puberty, the eel changes its appearance (the diameter of the eyes increases, the back turns from olive green to black, and the belly turns silvery-white), rolls into the sea and stops feeding. It is known that spawning migrations of eels in the Baltic Sea pass through coastal waters, but starting from the North Sea, their trail 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 different from their parents that they were at one time considered a different species of fish.

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

Not all questions related to the long migrations of European eels have been clarified. In addition to river eels, 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 hard body covered with plates of the exoskeleton. There is a pocket on the male’s belly that opens outwards with only a small hole.

For the entire breeding season, pipits 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. Egg laying usually occurs several times, so the small pipits in the male’s pouch can be of different ages, and then the older generation leaves the paternal pouch at intervals of several days.

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

Viviparity. Some species of fish do not lay eggs, but give birth to young that develop inside the mother's body. In this case, the development of the larva occurs directly in the female’s oviduct due to the nutrients present in the egg. Viviparous fish species include not only sea giants (sharks, rays), but also very small fish (aquariumguppies, swordtails ).

The importance of fish in nature and human life. Fish protection and breeding

Role in nature. About 70% of the Earth's surface is covered with water, or more precisely, with aquatic biogeocenoses: stable communities of living organisms that developed during the historical development of the 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. Very interesting are the relationships in which different types of animals are connected to each other for mutual benefit (symbiosis). How does this happen inamphiprion (clown fish) and sea anemones.

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

The importance of fish in human life.Fishing - one of the most ancient forms of human economic activity. 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 plant products.

Fish (especially bony fish) are of great practical importance for humans. In addition to food products, fish serve as raw materials for medicine (fish oil, etc.), feed for livestock and poultry (feed meal), fertilizer for fields, technical fat, glue, leather and other materials used in the food and light industry. 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 marine fishing arecod, haddock, navaga, pollock, herring, herring, sardine, sea bass, flounder, saury, mackerel, tuna . In Russian rivers they catch sturgeon, salmon,ram, roach, pike perch and other fish. Meat, fat, and caviar are used as food.

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

Hundreds of thousands of people enjoy fishing and spearfishing, for whom this wonderful sport gives them 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 of water resources (due to oil tanker accidents, pollution caused by mining, coastal runoff discharges). In addition, using modern powerful fishing tools, 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 states: the most unstable factors in the existence of fish today are the purity of water, air conditions, and the preservation of species habitats. And it offers basic principles for environmentally friendly activities near and in water bodies.

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

World organizations adopt laws on the protection and use of the planet's fauna. In particular, all fishing enterprises, as well as amateur fishermen, are required to strictly observe the established fishing rules. The laws define fishing methods and seasons. The diameter of the net cells should be such as not to impede the emergence of juveniles from them. On the rivers and ponds of Russia, the use of nets is strictly prohibited, as is the killing of fish with explosions (after all, this would kill almost the entire population of a given section of the reservoir). Much attention should be paid to the construction of treatment facilities that prevent water contaminated by wastewater from factories and factories 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, sturgeon and salmon fish, for example, are of great value. Their meat and caviar are tasty and nutritious!

The characteristics of individual fish species are valued and used by humans. So, exported from AmericaGambusia spread to control mosquitoes. After all, she feeds on their larvae.

Variety of fish

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

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

TO freshwater include, for example, carp-like:roach, dace, asp, tench, barbel, bream, bleak, sabrefish, carp, crucian carp, cupid . In fresh waters, an important factor determining the distribution of fish is water flow.Bream lives only in running water. Butcrucian carp, rotan can live in small ponds and swampy lakes.

To those living in both fresh and sea water (i.e.passable ) include sturgeons, salmonids,freshwater eel etc. Migratory fish are usually able to adapt to strong fluctuations in water salinity. In addition, during their life cycle they need to prepare the body for large energy expenditures 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 at the bottom (flounder, catfish ).

There are peaceful fish among themherbivores species (eg silver carp ) and very aggressivepredators (pike, perch, catfish ).

Class Cartilaginous fish

Fishes 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 cartilaginous fish there are three orders:Sharks, Rays, Chimaeras .

Shark Squad. There are more than 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, a dark body color on top and light below.

Paired pectoral and pelvic fins provide the shark with up and down movement. The upper lobe of the caudal fin is usually longer than the lower one. Vision is black and white. Sharks have a well-developed sense of smell, with which they find prey. They live mainly in the seas. Most are active predators. They hunt fish, shrimp, and 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-nosed sharks, hammerhead shark, mako And large white . Sharks are a commercial target. Shark liver, which occupies 20–30% of body weight, is considered a valuable product.

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

The sizes of the slopes are different. The smallest stingray -dipteran from the Yellow Sea - has a width of 10–15 cm. The largest representative of the order ismanta ray – the fin span reaches 8 m and has a mass of about 2.5 tons.

On the ventral side of the stingray's body, 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 stingrays have electrical organs. Electrical discharges of up to 300 volts are produced, probably for protection purposes. Electrical processes in the muscle tissue of stingrays have not yet been properly explained. Stingrays are commercially available. Some are dangerous to humans.

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

It is believed that chimeras originated from ancient sharks and are a side branch of evolution. Whole-headed animals have been known since the Upper Devonian; currently only the order of chimeras exists. Of more than a dozen of its families, only 3 have survived to this day; about 30 species living from the shelf to the great depths of the World Ocean. Chimeras feed on marine invertebrates and fish. They have practically no commercial significance.

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 water has not left a single unnecessary 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 dorsoventrally or laterally, or vice versa have a spherical shape. Translational movement in water is carried out due to wave-like movements of the body. Some fish “help” themselves with their 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.

On the outside, the body of bony fish is covered with scales: placoid (teeth laid “in parquet”),ganoid (rhombic plates with a spike),cycloid (thin plates with a smooth edge) orctenoid (plates with spines), periodically changing as the animal grows. The growth rings on it allow one to judge the age of the fish.

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

The coloring of fish is very diverse. Typically, fish have a bluish or greenish back (to match the color of the water) and silvery sides and belly (hardly visible against the background of the light “sky”). Many fish are covered with stripes and spots for camouflage. On the contrary, the inhabitants of coral reefs amaze with a riot of colors.

Variety of bony fish

Most species of fish are classified as bony fish. They are divided into osteochondral, lungfish, lobe-finned and teleost.

Osteochondral, or sturgeon, fish includeBeluga, sterlet, Russian sturgeon . They have an osteochondral skeleton with a well-developed notochord, gill covers and a swim bladder. Along the body of sturgeon there are 5 rows of bone plates, between which there are small bone plates. The head, like a shark's, has an elongated snout. Near the mouth, located on the underside of the head, there are antennae. The caudal fin is unequally lobed.

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

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

Lungfishes are a small (only 6 species) ancient group of fish. Among themAustralian horntooth, African And South American lepidoptera . In lungfishes, the notochord is preserved throughout their lives and 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 develop 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 long droughts by burying themselves in the mud. The structure of the heart has also changed: the atrium is divided by an incomplete septum into left and right halves. The right half receives blood from the gills, and the left half receives blood from the lungs.

Dipnoi: Horntooth (barramunda) (7), lepidosiren (8), large protopter (mamba) (9).

Lungfishes are 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 the summer, when reservoirs become shallow, breaking up into a chain of pits - tanks with rotting water, he completely switches to breathing atmospheric air. Having put its snout above the water, it forcefully throws out the “exhausted” air and at the same time makes a groaning-grunting sound that spreads far throughout the surrounding area. The cattail feeds on mollusks, crustaceans, worms, and insect larvae.

Other representatives of lungfishes -African scalefish (up to 2 m long) and South American lepidoptera (up to 1 m long) when water bodies dry up, they bury themselves in silt and hibernate.

Lobe-finned fish are an ancient group of fish. Until the first half of the 20th century. they were considered an extinct branch of vertebrates that were once widespread in both fresh water and seas. Lozenge fins are close to lungfishes. Their skeleton was mainly cartilaginous. The notochord was absent in adult fish. The fins of lobefins were similar to the fins of a cattail, 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 lobefins.

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

Teleosts are the most numerous group of modern fish (about 96% of all species). Their skeleton is ossified, the notochord develops only in the embryo, and the scales are bony. A swim bladder is common for them. Bony fish include such valuable commercial species astuna, halibut, salmon, herring, pike and others. Common for our riverscrucian carp And bream - also bony fish. These fish live in almost all bodies of water on Earth.

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

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

All 9th ​​grade graduates who want to successfully move to the next level have a question: how to prepare for the State Examination? Preparing for the State Examination in Biology on your own or with a tutor is an individual choice for everyone, but you should remember that preparing on your own is fraught with a number of difficulties.

Preparing for the State Examination in Biology on your own

One of the most effective methods of self-preparation for the State Examination (OGE) in biology or mathematics is passing special tests. It is not enough to solve test tasks correctly. You need to be able to complete them in a strictly limited time period. Therefore, it is very important to learn in advance to control the time for completing 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. You should objectively assess the difficulty of tasks and choose the priority for their solution, taking this factor into account.
3. It is necessary to constantly compare your results with the correct answers to analyze your mistakes.
4. You need to use the spiral movement technique for tests.

Preparing for the GIA/OGE using multimedia aids

Independent preparation for the State Examination (OGE) in biology or mathematics is possible using various multimedia materials. Using information technology, students perceive, assimilate and consolidate material faster than using other methods. This effect is due to the 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 possible to easily move from one course to another.

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

Ready-made electronic products for preparing for the State Examination (OGE) in biology or mathematics make it possible to make the process as rich and interesting as possible. The training includes:

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

Disadvantages 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. Using 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 test tasks provided for by the State Examination Examination (OGE).

Theoretical materials often contain information that is not needed for exam preparation, so 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 state final certification tests.

Preparation with a tutor

The disadvantage of school education is that during the time allotted for lessons, teachers do not have time to provide their students with the entire amount of necessary information that is required to successfully pass 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 whom graduates can easily fill in the gaps in knowledge.

Benefits of classes with tutors:

• 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 where students plan to continue their studies. Most of them advertise their courses by placing a “preparing for the State Examination” stand.

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

Preparing for the State Examination 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 been successfully replaced by 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 provide assistance at any time of the day.

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

• learning at home;
• selecting the best teacher by viewing and analyzing profiles on the website;
• quick mastery of the most complex material;
• low cost of classes;
• high quality lessons, due to which graduates will be able to successfully pass the exam.

Moreover, to ask an urgent question, the student does not need to meet with the teacher in person - he can easily do this via the Internet.

Specialized chickens for preparing for the State Examination

Preparing for the State Examination in Biology with the help of elective courses

Elective courses in biology for 9th grade graduates using information technology include:

• 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 State Examination, and independent study of materials;
• passing tests and various tasks that were compiled in accordance with the testing 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;
• using a differentiated approach to students, taking into account their learning ability, by repeating the school course from the elementary level.

Preparation plan for the GIA (OGE) in biology remotely for 9th grade graduates

Graduates of the 9th grade have the opportunity to prepare from scratch for the State Examination in Biology, repeating all the necessary sections of the subject.

The main topics for preparation require 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 people and animals.
4. Neurohumoral regulation of vital processes of the body;
5. Musculoskeletal system;
6. Circulatory and lymphatic system.
7. Digestive, respiratory, metabolic systems, secretion of products and 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 Exam in biology online, without leaving your home, by taking specialized Foxford courses on the website http://foxford.ru/ or Lancman school - http://school-lancman.ru/. Teachers from leading Russian universities will provide all the necessary knowledge to successfully pass exams or prepare for Olympiads.

Taking Foxford courses involves complete immersion in the school curriculum, after which most students pass exams much 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 performance. At the same time, it gives schoolchildren who love biology the opportunity to understand it even better and take first place in city Olympiads or enter specialized universities in the country on budget places. Chairmen, jury members and Olympiad coaches help 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 MIPT, Moscow State University and other universities, jury members of olympiads, authors of biology textbooks;
• online classes in real time;
• consolidation of material by completing homework with guiding tips;
• use of an interactive textbook;
• the ability to view video recordings of past classes;
• monitoring the effectiveness of academic performance by assigning an objective assessment for knowledge of each subsection of biology;
• high level of comfort due to access to classes at any convenient time and a cozy workplace at the computer;
• possibility of paying for training in installments.

FAQ

1. How are classes conducted? - Students take classes on the website http://foxford.ru/ in real time. A schoolchild sees a tutor on the screen teaching a lesson near the school board. You can ask him a question at any time via text or voice chat.
2. How to join lessons? - All classes are held according to a strict schedule, and you can join them an hour before they start. Anyone who has paid access to the courses can do this by clicking on the “Connect” button.
3. How to do homework? - At the end of each lesson, the student gets access to homework and notes on topics already studied. While completing them, students can use interactive tips, refer to notes and recordings 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 to do if you didn’t manage to connect in time? - Those who joined the lesson after the due date can watch the missed lessons in video recordings.

Getting ready for the State Examination with Lancman school

Teachers at the Lancman school educational center have extensive experience in preparing graduates to take the Unified State Exam or State Examination, both in biology and in all other school subjects, participate in olympiads and enter a university. Training is conducted in groups of up to 6 people using video lessons.

Advantages of courses at Lancman school

1. Work for results. One group includes no more than six people, which allows the teacher to pay maximum attention to each of them.
2. Level up. On average, group members score 37 points higher on exam tests than their classmates.
3. Preparation for the Unified State Exam in all subjects.
4. Trial lesson is free.
5. An effective training program.
6. Convenient class schedule based on student requests.
7. Monitoring of knowledge through trial EGE monthly.

Conclusion

To summarize, it should be noted that if students prepare for exams on their own, they may encounter a number of difficulties. Sifting out important information from unnecessary information, choosing the right manual, and exercising self-control are quite difficult things for most schoolchildren. Classic classes with a tutor are more effective, since the teacher pays maximum attention to the student and uses an individual approach to his learning. However, lack of time to travel to tutors often forces one to abandon this method. The most effective and convenient way is thematic preparation 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 exams at the highest level, sitting in a comfortable chair in front of a computer, saving time and money. In this case, the student can choose the lesson schedule that will be most convenient for him, and if he misses a lesson, watch it in a video recording.

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

The OGE in biology is not mandatory, so 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 enroll in humanitarian universities in the relevant field, namely: future biologists, psychologists, chemists, geographers, doctors, athletes and rehabilitation specialists. In addition, the result affects the overall certificate score 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 mastery of the program in this discipline in a particular school, city, district or region.

The Federal Institute of 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 manage to cope with the maximum number of tasks.

Unlike other items, it is prohibited 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 on storage media.

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

• Early testing – 23.04. The reserve day for preliminary submission is 3.05.
• The general day for the OGE in biology is May 31. Reserve deadline – 18.06.
• Additional testing is scheduled for September 10. An additional reserve will take place on September 18. – last date for those wishing to pass the general state exam in biology.

KIM structure

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

1. Dealing directly with the foundations of biology as a science. Includes tasks about the role of biology for understanding natural processes, the practical application of this knowledge and areas of its use. In addition, this block contains questions on knowledge of experimental techniques and methods for studying living nature.
2. Alive 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 living nature.
3. Evolutionary processes and diversity of life forms. This section contains questions to test knowledge of the classification and diversity of living nature, evolutionary issues and variability of species diversity.
4. Human biology. This section of questions includes anatomical and physiological basis, origin, hygiene and basics of human health.
5. Fundamentals of interactions 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 specialized commission involved in preparing tickets for the OGE in biology in 2018 reported that the KIM meets all requirements, fully reflects all areas of knowledge and is able to fully reflect the student’s level of preparation. For this reason, there will be no changes to tickets or task structure.

As before, the tickets will contain questions from the syllabus from grades 5 to 9 of the biology course.

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

• Part 1. It contains 28 tasks that resemble the test principle. 22 basic questions require an answer in the form of a number or phrase next to the desired answer. The next 6 tasks require deeper knowledge of the subject.
• Part 2. 4 tasks that require longer study. In the first question, the answer must include a textual reflection of the required information. One assignment tests the ability to analytically group material presented in tabular format. The last 2 tasks are aimed at the practical application of theoretical knowledge.

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

How work is evaluated

After a complete check, the work is assigned a certain score, which means a specific rating.

To understand what grade 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 to tasks No. 1-22 earns the student 1 point;
• starting with No. 23 and ending with No. 27, the correct answer earns 2 points. 1 point is lost if the answer contains more than one answer, and one of them is incorrect;
• a complete answer to question No. 28 adds 3 points, and in case of partial completion - 2 or 1 point in proportion to completion;
• 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 their performance in the certificate, strive to begin preparing for the OGE in advance.

Preparation may include the following steps:

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

The basis for preparation is the assignments of previous years, since no fundamental changes have been observed recently.

Disputing the results

If you disagree with the assessment obtained as a result of the OGE in biology, you can file an appeal with 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 results are announced. 4 business days are allotted for consideration of the complaint (only Sundays are excluded). The work is reviewed and assessed again by the conflict commission.

Video tips self-study:

THEORETICAL MATERIAL

BIOLOGY AS A SCIENCE. METHODS OF BIOLOGY

Biology - the science of life, its patterns and forms of manifestation, its existence and distribution in time and space. She explores the origins of life and its essence, development, interconnections and diversity. Biology belongs to the natural sciences.

The term “biology” was first used by the German professor of anatomy T. Ruz in 1779. However, it became generally accepted in 1802, after the French naturalist J.-B. began to use it in his works. Lamarck.

Modern biology is a complex science, consisting of a number of independent scientific disciplines with their own objects of research.

BIOLOGICAL DISCIPLINES

Botany- plant science,

Zoology- animal science,

Mycology- about mushrooms,

Virology- about viruses,

Microbiology- about bacteria.

Anatomy- a science that studies the internal structure of organisms (individual organs, tissues). Plant anatomy studies the structure of plants, animal anatomy studies the structure of animals.

Morphology- a science that studies the external structure of organisms

Physiology- a science that studies the vital processes of the body and the functions of individual organs.

Hygiene- the science of preserving and strengthening human health.

Cytology- cell science.

Histology- tissue science.

Taxonomy- the science of classifying living organisms. Classification is the division of organisms into groups (species, genus, families, etc.) based on structural features, origin, development, etc.

Paleontology- a science that studies the fossil remains (imprints, fossils, etc.) of organisms.

Embryology- the science that studies the individual (embryo) development of organisms.

Ecology- a science that studies the relationships of organisms with each other and with the environment.

Ethology- the science of animal behavior.

Genetics- the science of the laws of heredity and variability.

Selection- the science of breeding new and improving existing breeds of domestic animals, varieties of cultivated plants and strains of bacteria and fungi.

Evolutionary doctrine- studies the origins and laws of the historical development of life on Earth.

Anthropology- the science of the emergence and development of man.

Cell engineering- a branch of science dealing with the production of hybrid cells. An example is the hybridization of cancer cells and lymphocytes, the fusion of protoplasts of different plant cells, and cloning.

Genetic Engineering- a branch of science that deals with the production of hybrid DNA or RNA molecules. If cell engineering works at the cellular level, then genetic engineering works at the molecular level. In this case, specialists “transplant” the genes of one organism to another. One of the results of genetic engineering is the production of genetically modified organisms (GMOs).

Bionics- a direction in science that searches for opportunities to apply the principles of organization, properties and structures of living nature in technical devices.

Biotechnology- a discipline that studies the possibilities of using organisms or biological processes to obtain substances needed by humans. Typically, biotechnological processes use bacteria and fungi.

GENERAL METHODS OF BIOLOGY

A method is a way of understanding reality.

1. Observation and description.

2.Measurement

3. Comparison

4. Experiment or experience

5. Simulation

6. Historical.

STAGES OF SCIENTIFIC RESEARCH

Held observation over an object or phenomenon

based on the data obtained, it is put forward hypothesis

scientific experiment(with control experience)

a hypothesis tested during an experiment can be called
theory or by law

PROPERTIES OF LIVING

Metabolism and energy flow- the most important property of living things. All living organisms absorb the substances they need from the external environment and release waste products into it.

Unity of chemical composition. Among the chemical elements in living organisms, carbon, oxygen, hydrogen and nitrogen predominate. In addition, the most important feature of living organisms is the presence of organic substances: fats, carbohydrates, proteins and nucleic acids.

Cellular structure. All organisms are made up of cells. Only viruses have a non-cellular structure, but they also show signs of being alive only after entering the host cell.

Irritability- the body’s ability to respond to external or internal influences.

Self-reproduction. All living organisms are capable of reproduction, that is, the reproduction of their own kind. Reproduction of organisms occurs in accordance with the genetic program recorded in DNA molecules.

Heredity and variability.

Heredity is the ability of organisms to pass on their characteristics to their descendants. Heredity ensures continuity of life. Variability is the ability of organisms to acquire new characteristics in the process of their development. Hereditary variability is an important factor in evolution.

Growth and development.

Growth - quantitative changes (for example, increase in mass).

Development - qualitative changes (for example, the formation of organ systems, flowering and fruiting).

Self-regulation - the ability of organisms to maintain the constancy of their chemical composition and vital processes - homeostasis.

Adaptation

Rhythm - periodic changes in the intensity of physiological functions with different periods of fluctuations (daily, seasonal rhythms). (For example, photoperiodism is the body’s reaction to the length of daylight hours).

Levels of life organization

Test tasks in OGE format

What science studies the varietal diversity of plants?

1)physiology 2)systematics 3)ecology 4)selection

2. You can find out whether light is necessary for the formation of starch in leaves using

1) descriptions of plant organs 2) comparisons of plants from different natural zones

3) observations of plant growth 4) photosynthesis experiment

3. In what area of ​​biology was cell theory developed?

1) virology 2) cytology 3) anatomy 4) embryology

4. To separate cell organelles by density, you will choose a method

1) observation 2) chromatography 3) centrifugation 4) evaporation

5. The photograph shows a model of a DNA fragment. What method allowed scientists to create such a three-dimensional image of a molecule?

1) classification 2) experiment 3) observation 4) modeling

6. The photo shows a ball-and-stick DNA fragment. What method allowed scientists to create such a three-dimensional image of a molecule?

classification 2) experiment 3) observation 4) modeling

7. The use of which scientific method illustrates the plot of the painting by the Dutch artist J. Steen “Pulse”, written in the middle of the 17th century?

1) modeling 2) measurement 3) experiment 4) observation

8. Study the graph reflecting the process of growth and development of the insect.

Determine the length of the insect on the 30th day of its development.

1) 3,4 2) 2,8 3) 2,5 4) 2,0

9. Which of the following scientists is considered the creator of the doctrine of evolution?

1) I.I. Mechnikov 2) L. Pasteur 3) Ch. Darwin 4) I.P. Pavlova

10. What science studies the varietal diversity of plants?

1) physiology 2) taxonomy 3) ecology 4) selection

11. Select a pair of animals whose experiments have led to major discoveries in animal and human physiology.

1) horse and cow 2) bee and butterfly 3) dog and frog 4) lizard and dove

12. In what area of ​​biology was cell theory developed?

1) virology 2) cytology 3) anatomy 4) embryology

13. You can accurately determine the degree of influence of fertilizers on plant growth using the method

1) experiment 2) modeling 3) analysis 4) observation

14. An example of the application of an experimental research method is

1) description of the structure of a new plant organism

2) comparison of two microslides with different tissues

3) counting a person’s pulse before and after exercise

4) formulating a position based on the facts obtained

15. A microbiologist wanted to find out how quickly one type of bacteria multiplies in different nutrient media. He took two flasks, filled them halfway with different nutrient media and placed approximately the same number of bacteria in them. Every 20 minutes he removed samples and counted the number of bacteria in them. The data from his research are reflected in the table.

Study the table “Change in the rate of reproduction of bacteria over a certain time” and answer the questions.

Change in the rate of bacterial reproduction over a certain time

1) How many bacteria did the scientist put in each flask at the very beginning of the experiment?

2) How did the rate of bacterial reproduction change during the experiment in each flask?

3) How can we explain the results obtained?

Literature

Kamensky A.A., Kriksunov E.A., Pasechnik V.V. Biology. General biology 9th grade: textbook. for educational institutions. M.: Bustard, 2013.

Zayats R.G., Rachkovskaya I.V., Butilovsky V.E., Davydov V.V. Biology for applicants: questions, answers, tests, tasks. - Minsk: Unipress, 2011. - 768 p.

“I will solve the OGE”: biology. Dmitry Gushchin's training system [Electronic resource] - URL: http:// oge.sdamgia.ru