Pisces class- This is the most numerous group of modern vertebrates, which unites more than 25 thousand species. Fish are inhabitants of the aquatic environment, they breathe with gills and move with the help of fins. Fish are common in different corners planets: from high-altitude reservoirs to ocean depths, from polar waters to equatorial ones. These animals inhabit the salty waters of the seas, are found in brackish lagoons and the mouths of large rivers. They live in fresh rivers, streams, lakes and swamps.

The external structure of the fish

The main elements of the external structure of the body of the fish are: head, gill cover, pectoral fin, ventral fin, torso, dorsal fins, lateral line, caudal fin, tail and anal fin, this can be seen in the figure below.

The internal structure of fish

Fish organ systems
	1. Skull (consists of the braincase, jaws, gill arches and gill covers) 2. The skeleton of the body (consists of vertebrae with processes-arcs and ribs) 3. Skeleton of fins (paired - pectoral and ventral, unpaired - dorsal, anal, caudal)	1. Brain protection, food capture, gill protection 2. Protection of internal organs 3. Movement, balance
musculature	Wide muscle bands divided into segments	Traffic
Nervous system	1. Brain (sections - anterior, middle, oblong, cerebellum) 2. Spinal cord (along the spine)	1. Movement control, unconditioned and conditioned reflexes 2. Implementation of the simplest reflexes, conduction of nerve impulses 3. Perception and conduction of signals
sense organs	3. Organ of hearing 4. Touch and taste cells (on the body) 5. Lateral line	2. Smell 4. Touch, taste 5. Feeling the direction and strength of the current, the depth of immersion
Digestive system	1. Digestive tract (mouth, pharynx, esophagus, stomach, intestines, anus) 2. Digestive glands (pancreas, liver)	1. Capturing, grinding, moving food 2. secretion of juices that contribute to the digestion of food
swim bladder	Filled with a mixture of gases	Adjusts the immersion depth
Respiratory system	Gill filaments and gill arches	Carry out gas exchange
Circulatory system (closed)	Heart (double-chambered) arteries capillaries	Supply of all cells of the body with oxygen and nutrients, removal of decay products
excretory system	Kidneys (two), ureters, bladder	Isolation of decay products
Breeding system	In females: two ovaries and oviducts; In males: testes (two) and vas deferens

The figure below shows the main systems of the internal structure of the fish

Fish Class Classification

Currently living fish are divided into 2 main classes: cartilaginous fish and bony fish. Important distinctive features cartilaginous fish - the presence of an internal cartilaginous skeleton, several pairs of gill slits that open outwards, and the absence of a swim bladder. Almost all modern cartilaginous fish live in the seas. The most common among them are sharks and rays.

The vast majority of modern fish belongs to the class of bony fish. Representatives of this class have a ossified internal skeleton. A pair of external gill slits are covered with gill covers. Many bony fish have a swim bladder.

The main groups of Pisces

Squads of fish	The main features of the detachment	Representatives
	Cartilaginous skeleton, no swim bladder, no gill covers; predators	Tiger shark, whale shark, katran
	Manta, stingray
Sturgeons	Osteo-cartilaginous skeleton, scales - five rows of large bone plates, between which there are small plates	Sturgeon, beluga, sterlet
Dipnoi	They have lungs and can breathe atmospheric air; notochord preserved, no vertebral bodies	Australian horned tooth, African flake
Crossopterygians	The skeleton mainly consists of cartilage, there is a notochord; poorly developed swim bladder, fins in the form of fleshy outgrowths of the body	Latimeria (the only representative)
Cypriniformes	Mostly fresh water fish, no teeth on the jaws, but there are pharyngeal teeth for grinding food	Carp, crucian carp, roach, bream
herring	Most are schooling marine fish	Herring, sardine, sprat
Cod	A distinctive feature is the presence of a mustache on the chin; most are cold-water marine fish	Haddock, herring, na-vaga, burbot, cod

Ecological groups of fish

Depending on the habitats, ecological groups of fish are distinguished: freshwater, anadromous, brackish and marine.

Ecological groups of fish	Main features
freshwater fish	These fish constantly live in fresh water. Some, such as carp and tench, prefer stagnant water. Others, such as the common minnow, grayling, chub, have adapted to life in the flowing waters of rivers.
migratory fish	This includes fish that migrate from sea water to fresh water to breed (for example, salmon and sturgeon) or from fresh water to breed in salt water (some types of eels)
brackish fish	They inhabit desalinated areas of the seas, the mouths of large rivers: such are many whitefish, roach, goby, river flounder.
sea ​​fish	They live in the salt water of the seas and oceans. The water column is inhabited by fish such as anchovy, mackerel, tuna. At the bottom live stingray, flounder.

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The source of information: Biology in tables and diagrams. / Edition 2e, - St. Petersburg: 2004.

1. Draw a table in your notebook and fill it in as you study the orders of bony fish

2. Remember the features of the structure of cartilaginous fish. What features of sturgeons emphasize their similarity to cartilaginous fish?

The spine retains the notochord

3. Sturgeons are also called anadromous fish. Explain this name

They spend most of their life in salt water, rise into rivers for spawning

4. Summer-spawning (“summer”) herrings of the White Sea breed under conditions of significantly greater activity of predators than spring-spawning (“spring”) herrings. Scientists have found that the herring of one of these groups spawns from 2.3 thousand to 21 thousand eggs, while others from 9.2 thousand to 62 thousand eggs. Determine the fertility of "summer" and "spring" herring. Justify your answer

In summer - from 9.5 to 61 thousand caviar

Spring - from 2 to 20 thousand caviar

Yes, most salmon species can be considered anadromous

6. Why are piranhas dangerous for animals and humans?

The piranha's teeth allow them to tear large chunks of meat from the body of their prey.

7. Explain why one type of eel is called electric. Why does he need electrical discharges?

Electrical discharges serve to protect against enemies and to obtain food.

8. What feature in the behavior and respiration of electric eels allows them to live in water bodies with a minimum amount of oxygen?

There are areas of tissue that allow you to absorb oxygen

9. List the types of fish bred in fish farms

Carp, tench, pike, zander, sabrefish

10. Name the types of fish of the cyprinoid order, bred in aquatic aquariums

Barbs, labeo, goldfish

11. As per appearance the structure can be distinguished by perch-like fish

The pelvic fins are located under the pectorals. The fin has the shape of an undivided sharp spike

12. Complete the scheme "Families of the order Perciformes"

1. stone perch

2. perch with childbirth

3. scad

4. crucian carp

5. rotosthenic

6. catfish

7. bull

8. sailboats

13. Look at pictures 94 and 95 of the textbook (pp. 111 and 112). Write down the species names of fish of the Cyprinidae and Perciformes orders, which you caught in the rivers and lakes of your area

Squad Cyprinoid: bream, carp

Order Perciformes: perch, pike perch

14. Look at the pictures. Write down the numbers of the fish included in the corresponding orders.

Order Sturgeons: 6, 3

Order Herring-like: 5, 7

Order Salmonformes: 10, 8

Order Cyprinidae: 2, 4

Order Perciformes: 1, 9

15. Look at the pictures, sign the names of the fish

16. Why are protoptera, lepidosiren, horntooth classified as lungfish?

They breathe in water and on land

17. What do the habitats of lungfish living in Africa, America and Australia have in common?

They have a prototype of the lung, they can withstand the drying up of the reservoir

18. What changes in the fins of coelacanths allow us to call them lobe-finned fish?

Paired fins serve as support, represent lobes, consisting of several cystic segments

19. Remember the similarities between sharks and lobe-finned fish

Two-chambered heart, live in water. axial skeleton in the form of a chord

20. Explain why lungfish and lobe-finned fish can be considered transitional forms between aquatic and terrestrial animals

In the absence of water, they can switch to pulmonary respiration.

"Commercial fish" - Detachments of commercial fish. Order Salmonformes. Salmon. Detachment cod-like. Cypriniformes. Codfish. Order Cyprinidae. Sturgeons. Diversity of commercial fish. Order Herring. Squad Sturgeons. Herring.

"Class of Fish" - The body of fish is complex. What environment do fish live in? The meaning of fish. The internal structure of the body of a fish. What groups is the Vertebrate subtype divided into. Answer the test questions. What have we learned. The external structure of fish. The main organ systems of fish. Sense organs. Respiratory system. Habitat. What group of living organisms are we studying.

"Fish biology" - Aquaculture has two main areas. Biology and pathology of fish. The main production and technological processes in pond fish farming. The purpose of the discipline: And the second is the artificial reproduction of aquatic biological resources.

"Amazing Fish" - Biology Presentation on the Theme: Amazing Fish. angler. Whale shark. The anglerfish is a predatory marine fish. There is no chin barbel, and there is a non-functioning gut. The venom of the wart is extremely dangerous. sailboat. Dragon fish. Idiacant, or "dragon fish", is a long, flexible fish. Shell pike. This fish lives at depths of 600-1200m on the coast of Australia and Tasmania.

"A fish is an animal" - Instinct is prophetically blind. Detachments. Glue production source. Make up a crossword puzzle. Name the fish. Fish classes. Variety of fish species. Skat. The number of species. Finish the proverbs. Choose the correct ones from the given sentences. Large aquarium. general characteristics class of fish. Pipefish. Fish classification.

"Variety of fish" - Birds. Grow. Flounder. Cockerel. Mystery. The fish is the moon. Omnivorous. Skate. Predators. Fins. Develop. Parents and children have all clothes from coins. Som. Breathe. Marine. Fish is a horse. Carp. V - already knew + - learned something new? - I want to know. Scales. 2 legs, feathers, wings, beak breathe with lungs. Fish. Head. Animals.

There are 18 presentations in total in the topic

Fish are vertebrates that live in water bodies and breathe with gills. In the world there are more than 3 thousand species. It is believed that it was they who first came to land, giving rise to land animals. What classes and orders of fish are there? How do they differ from each other? What order does the moonfish, the heaviest fish in the world, belong to? We will answer all these questions in this article.

Why are fish unique?

Fish are an integral part of many ecosystems and important participants in food chains. They are widespread on the planet, inhabiting salt and fresh water bodies from oceans to high mountain lakes located at an altitude of more than 6 kilometers.

They spend most of their lives in the water, so the main respiratory apparatus for them is the gills. In many orders of fish there are representatives who are able to briefly crawl out to the surface (silty jumper, climbing perch, some even developed additional respiratory organs - lungs (lungfish - protopterus, horntooth, etc.).

Almost constant life under water required special adaptations from fish. Their outer covers are represented by scales - plates of dentin, cosmin or gaonin, which are superimposed on each other, like tiles.

They move with the help of fins, and to reduce the body, their body has a streamlined shape. Many fish exist by regulating the pressure, it contributes to the vertical movements of the animal in the water column, and also helps them to linger at a certain depth.

Fish classification

Fish are a group of chordates, within which several classes are distinguished. AT various sources their numbers diverge. Usually they are divided into cartilage and bone. Sometimes bony fishes are distinguished as a superclass, and within it the classes of ray-finned and lobe-finned are distinguished.

Orders of cartilaginous fishes are chimera-shaped, katran-shaped, stingray-shaped, angelfish, multigilled, lamniform and others. There are about 13 of them in total, and they represent their various rays and chimeras.

The skeleton of these fish is made up of cartilage. In stingrays and sharks, the gills are not covered by a lid, but go out with slits. The swim bladder is missing, which forces them to constantly be in motion, otherwise they will fall to the bottom. Some species do not lay eggs, but reproduce by live birth.

Orders of the bony fish class are more numerous. As the name implies, their skeleton is made up of bones. The gills are part of the skeleton, they consist of petals and stamens, and are covered with lids on top.

It is impossible to list all the orders of fish at once in one article, so below we will describe the most interesting or common of them.

Perciformes

The largest detachment of fish, which covers about 7-8 thousand species. Most of them are commercial. main feature fish of the perch-like order - ctenoid scales. Its edges are not even, but are divided into many small teeth. Their pectoral fins are located under the pectorals, and part of the ray fins is turned into spikes.

Perciformes vary greatly in size. Some species reach only a few centimeters (Lucion mystichthys), while others grow up to 3 meters (bluefin tuna). Typical representatives are mackerel, gobies, pike perch, tuna, gourami, swordfish. But sea ​​bass they do not belong to them and belong to the scorpion-like order.

Chimeras

The fish of the chimera order have a somewhat bizarre appearance. Their body is elongated and strongly narrowed to a whip-like tail. There is a spike in front of the two dorsal fins that can be hidden in a fold on the back.

The nose is pointed and has a triangular shape. In some species, it is strongly elongated, and resembles a proboscis. The mouth is located below. The pectoral fins are large and shaped like wings.

Chimeras swim slowly, "hovering" in the water. These are living at great depths or shelf shallows. They are found in the Indian, Atlantic and Pacific Oceans. They reproduce by laying eggs.

sturgeons

In structure, sturgeons occupy an intermediate position between the cartilaginous and bone orders of fish. Usually they are classified as a class of bones and a subclass of cartilaginous. These include beluga, all kinds of sturgeon, kaluga, sterlet, etc.

Their skeleton consists of cartilage, has a notochord and is not divided into vertebrae. The body of the fish is elongated and covered with five rows of large bony plates, between which are smaller scales. The mouth is located below. In front of him are four antennae, playing the role of organs of touch.

Sturgeons live in the rivers and seas of the Northern Hemisphere. Fishing for them is very common, caviar is especially valued. These are quite large fish. Belugas, for example, reach 4-9 meters, sturgeons - 6 meters.

Pufferfishes

This order of bony fish includes about 250 species. Most representatives have an unusual body shape: spherical, flattened disc-shaped, cubic, etc. The mouth of the fish is usually small, the bones of the upper jaw are tightly closed. Instead of ordinary scales, their body is covered with spikes or small needles.

They inhabit warm ocean waters near the equator, preferring coral reefs. Outstanding representatives are fish-hedgehog, fish-moon, boxfish-cube and others. The sunfish is the heaviest fish in the world. Its weight can exceed 20 tons. It has a disc-shaped shape, flattened laterally and reaches up to 2 meters in diameter.

Flatfishes

Flounder - flat fish swimming on its side. They also lie on their side, so their eyes are placed only on one side. The color is usually close to the color seabed. This is necessary for camouflage, because almost all fish of the detachment are predators and feed on crustaceans, mollusks and small fish.

They inhabit the seas from tropical to temperate zones, living mainly near the bottom. Fish prefer shallow water, hotel species easily swim into the mouths of rivers. These include flounder, halibut, limed. The smallest representatives are 7-8 centimeters, the largest - about 5 meters.

herring

Herrings represent one of the most primitive orders of bony fish. Their body is slightly flattened and covered with semicircular scales. The skull of many fish is made up of cartilage. The rays of the fins are very soft, which is why the detachment is often called "soft-finned". The order includes Atlantic menhaden, Baltic and Pacific herring, sardines, sprats, anchovies, herring, sprat.

These fish are very diverse in their way of life, many are able to make long migrations. They are distributed in all oceans of the world, especially in tropical regions and subtropical regions. Subpolar regions are inhabited by only a few species, some also live in fresh water. Most belong to pelagic fish - living in the upper layers of the ocean.

eels

Unusual representatives of bony fish are the eel-like detachment. Due to their long, elongated body, they can be confused with snakes. However, the body of eels does not taper towards the tail and is often not even laterally flattened.

They move by twisting. The fish do not have ventral fins, exactly like scales. The skin is covered with mucus. Like snakes, they may not have ribs, and the backbone is up to 300 vertebrae. Most eels are venomous and predatory. Especially large species (giant moray eels) even attack reef and tiger sharks.

They prefer warm waters. They are represented by various types of moray eels and eels. The only freshwater family is river eels. They live in water bodies that belong to the basins of the Atlantic, Pacific and Indian Oceans.

gray sharks

Among all sharks, the most numerous is the group of carcharid or gray sharks. It includes more than 250 species, including the hammerhead shark, tiger shark, silky shark, blunt shark, etc. Its representatives are considered one of the most dangerous inhabitants of the deep sea. On account of their many human victims.

They live in the coastal zones of the seas of the tropical, subtropical and temperate zones. Fish are constantly moving, sometimes moving away into the depths of the ocean, sometimes swimming in shallow water. Some species also appear in fresh water.

Gray sharks have five pairs of gill slits, two dorsal fins, and one anal fin. They reproduce either by laying eggs or live birth.

They have a large mouth located at the bottom, and the snout is extended forward. In some sharks, it is very rounded (in blunt-nosed sharks). specific view has a hammerhead shark. Their muzzle is flattened at the top and broad laterally, resembling the leading edge of a hammer. The first dorsal fin is crescent-shaped.

Lesson topic: Cartilaginous fish

Subject: biology

Class: 7

Goals: to study the class Cartilaginous fish, their diversity, habitat, behavior, lifestyle.

Lesson objectives

Tasks:

learn the main features of cartilaginous fish;

understand the classification

identify traits of adaptability to the environment;

learn the meaning in nature and in human life;

be able to recognize representatives of the Sharks, Stingrays and Chimeras;

develop the ability to observe animals while watching a video clip;

Equipment: table "Cartilaginous fish", presentation.

Planned results:

students should know:

features of the external and internal structure of cartilaginous fish;

adaptability of cartilaginous fish to environmental conditions;

the role of cartilaginous fish in nature and their importance in human life;

students should be able to:

recognize representatives of the Sharks, Stingrays, Chimaeroids orders.

Stroke lesson a.

1. Organizational moment.

Greeting, message of the topic of the lesson and work plan, mark absent.

2. Knowledge check

Written survey

Biological dictation. Insert the missing word.

Fish are animals belonging to the Type of …….. and having mastered …. habitat. The body of the fish has …….. the shape of the body and is divided into sections: …, ……., ……. Outside, the skin of the fish is covered ..... Movement is provided by ... .... Paired fins .... and ..., unpaired ...………,…………, ………… The horizontal position of fish, turns, movement up and down are carried out by……………….. Respiratory organs of fish…….. Circulatory system of fish ….. The heart of fish consists of …. cameras: …and…. Through the heart of the fish flows …………… The respiratory system of fish is represented by………… The excretory organs of fish…., are located under the spine.

Compare your answer with the standard and give yourself marks:

0 errors - "5"

1 mistake - "4"

2 errors - "3".

3 . Learning new material.

Formulation of the topic of the lesson and the formulation of the educational problem.

Teacher: I'll give you a riddle now, try to guess who it is.

This terrible white predator

Looking for food in the ocean.
Sensitive nostrils on the snout:
You can smell blood from a mile away.
It circles around the victim,
And the circles are already, already.
Turns up his nose ... Oh my god!
The jaw looks like a trap!
She closed her sharp teeth.
So hunt...

Students: Shark.

So, the topic of the lesson: Cartilaginous fish.

Teacher: Let's formulate the goals of our lesson:

1. get to know the orders of cartilaginous fish,

2. learn the structural features of cartilaginous fish

3. learn to recognize cartilaginous fish by their appearance:

4. learn about the diversity of cartilaginous fish species.

(students try to formulate the goal of the lesson with the help of the teacher)

Teacher: In the process of work, the table "Squads of Cartilaginous Fish" is filled in.General characteristics of cartilaginous fish. (Teacher's explanation with elements of conversation.)

On the desk

– What fish are cartilaginous?

– On the basis of what features they are combined into one group?

– How are cartilaginous fish adapted to their environment?

– What type are the fish? (chordates)

– What subtype? (vertebrates)

Today we will get acquainted with the class of cartilaginous fish.slide 3

In order to find out common features cartilaginous fish, let's watch a movie. slide 4

– What features did you see?

Squads of cartilaginous fish

Related to ancient armored fish

Among the primitive antiarchs, the whole body was chained in a shell of skin plates;

In predatory arthrodires, the shell covered only the front of the body.

Armored - the first jawed fish; their jaws arose from gill arches that moved closer to the mouth, and consisted of pointed bony plates.

The armored fish became extinct at the end of the Devonian.

The class of cartilaginous fish includes 3 orders:

Shark squad (250 species)

Order Stingrays (350 species)

Order Chimaeriformes (30 species

1. Shark Squad.

slides 7-13)

Variety of sharks.

General characteristics of sharks

The respiratory system begins with 5–7 pairs of gill slits.

In the intestine, a spiral valve stretches along its entire length, increasing the suction surface.

The arterial cone of a two-chambered heart is capable of independent contraction and gives an additional blood impulse.

The sense organs are represented by the organs of smell, sight, touch( )

Fertilization in almost all cartilaginous fish is internal.

Many of them have a cloaca.

Cartilaginous fish are viviparous or lay eggs.

2. Detachment Stingrays.

Teacher's explanation with elements of conversation ( slides 14-17)

Look at the picture. What traits of adaptability to the environment did you see?

General characteristics of slopes.

Gill slits are located on the ventral side

The body is strongly flattened.

Wide pectoral fins grow to the edges of the body and head. The caudal fin is thin, and its lobes are often reduced. The anal fin is absent.

They use their pectoral fins to move, flapping them like wings.

The spatters are much better developed than those of sharks.

Most species are seabed dwellers, giving their backs a protective coloration that matches the color of the ground.

Skates reproduce by laying encapsulated eggs on the bottom or by live birth.

3. Detachment Chimaeriformes.

Teacher's explanation with elements of conversation ( slides 18-20)

General characteristics of chimeras.

The jaws are completely fused with the skull.

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.

They live from the shelf to the great depths of the oceans.

Chimeras feed on marine invertebrates and fish.

They have practically no commercial value.

Teacher: Let's check how you filled out the table.

(pupils read the table)

Order name, number of species.

4. Fixing.

You take true statements

1) in cartilaginous fish, the gills are covered with cartilaginous lids;

3) most stingrays are bottom-dwelling life;

4) sharks and rays lead a benthic lifestyle;

5) all sharks are dangerous to humans;

6) cartilaginous fish have highly developed muscles;

7) cartilaginous fish have a swim bladder;

8) the skin of cartilaginous fish is covered with scales;

9) the body of stingrays is torpedo-shaped;

10) the coloring of rays is patronizing.

6. Reflection.

7. Homework.

1. Section 22.

2. Prepare messages about sharks and rays on the topics: "Manta - sea devil", "Katran - herring shark", "Truth and fiction about sharks".