Mollusk type: general characteristic. Type and classes of mollusks

Mollusks, or mild, form a clearly limited type of animal, leading the beginning of the ringed worms. Molluscs include mainly aquatic, less frequently terrestrial animals characterized by the following signs.

Mollusca type consists of a large number of very diverse forms - more than 100,000 species. These are soft non-banned animals with a true body cavity (whole). In size, they can range from several millimeters to more than 20 m (as in the case of a giant squid Architheutis, the largest of invertebrates). Among the mollusks found several of the most interesting and valuable objects for neurobiological studies. As shown in Fig. 4.3 They developed 700 or 800 million years. Mollusks are divided into 7 classes.

1. Mollusks - bilateral - symmetric animals, however, in part of the mollusks due to a peculiar bias, the body becomes asymmetric.

2. The body of the mollusks is non-genuine, only a number of lower representatives detect some signs of metamery.

3. Mollusks are secondary animals with non-metamatic residual whole, presented in most forms of the near-handing bag (pericardium) and the gonad cavity. All intervals between the organs are filled with a connective tissue.

4. The body of mollusks, as a rule, consists of three departments - head, torso and legs. Very often, the torso grow up on the spinal side as an internal bag. The leg is a muscular unpaired abdominal body wall, serves to move.

5. The base of the body is surrounded by a large skin fold - mantle. There is a mantle cavity between the mantle and the body, in which there are gills, some senses organs and opening the rear openings, kidneys and sexual apparatus. All these formations along with the kidneys and heart (located in the close neighborhood with the mantle cavity) are called the mantle complex of organs.

6. On the spinal side of the body, as a rule, the protective sink is allocated by the mantle, more often, less often double, or consisting of several plates.

7. For most clams, the presence in the throat of a special apparatus for crushing food - graters (Radules).

8. The blood system is characterized by the presence of a heart consisting of ventricle and atrial; It is not closed, that is, part of its path the blood passes through the system not decorated in the vessels of Lakun and sinus.

Respiratory organs are usually represented by primary habies - claddia. The latter, however, in a number of forms disappear or replaced by the respiratory authorities of other origin.

For selection, kidneys are used - modified coloders communicating with internal ends with a window-shaped bag.

9. The nervous system in primitive forms consists of a convection ring and four longitudinal trunks; At the highest forms on the trunks, several pairs of ganglia are formed as a result of the concentration of nerve cells. The nervous system of this type is called scattered - nodal.

10. The development of mollusks is very similar to such multi-minded worms; In most crushing spiral type, deterministic. The lower representatives from the egg comes out Throchor, most of the others are a modified three-phophula larva - a sailboat (Verger).

The type of clams includes 7 classes. The most important of them:

labor (Gastropoda) - Slowly crawling snails
bivalve (Bivalvia) - relatively sedental clams
cHONEVOGE (CEPHALOPODA) - movable mollusks

The type of mollusks, numbering about 130,000 species, is inferior in the number of species only arthropod and is the second largest type of animal world. Mollusks are predominantly water inhabitants; Only a small number of species dwells on land.

Mollusks have a variety of practical importance. Among them are useful as pearls and pendants, which are mined in order to obtain a natural pearl and pearl. Oysters and some other types are mined and even bred for use in food. Some species are pests of agricultural crops. From a medical point of view, the mollusks are of interest as the intermediate hosts of helminths.

Damage to gardens, gardens, vineyards naked slugs, grape snail. Mollusks play a large role in the biological water purification, constantly filtering it to cooking. On marine plantations for food purposes, bivalve mollusks are divorced.

In the Red Book of the USSR, 19 species of representatives of this type of animals were made.

Type of lesson: Lesson-seminar.

Educational Objectives: Checking the level of assimilation of the main concepts of the topic "General characteristic of mollusks", checking and consolidating knowledge of students on the features of the structure of the body of mollusks, processes of vital activity, the continuation of the formation of knowledge skills in solving biological problems, the development of educational skills of analytical synthetic activities, the formation of environmental Student cultures.

FEATURES OF METHODS: Using a computer presentation, video phrase, interactive tasks, as funds to actualization of students' knowledge and the development of their natural science thinking.

Equipment: Computer, Projector, Interactive Board, Disk "Multimedia Manual" Kirill Lessons and Methodius "Animals", Laser Pointer, Projector, Magnets, Didactic Cards, Marine and Freshwater Shells.

During the classes

I. Orgmant.
goals and objectives of the lesson;

methodical features.

2. Blitz - Survey "Question - Answer."

Symmetry type of mollusks? ( bilateral, asymmetry)
Outer layer of shell? ( konchiolin)
Middle layer of shell? ( prismatic, or porcelain)
Inner layer of shell? ( pearl)
Muscular tongue seated by transverse rows of kilolic teeth? ( tyrka, or Radules)
Digestive iron? ( liver)
Gills of mollusks? ( kothenia)
Type of blood system? ( unlocked)
Heart departments? ( atrium, stomach)
Allocation authorities? ( kidneys-Nephdia)
Type of nervous system? ( scattered nodal)
Mollusk larvae? (Trichofora, Vigiger (Sailboat), Glocheidium)

III. Oral responses at the boards on the proposed seminar issues.

1. Classification of mollusks. ( Presentation , slides number 2-15)

The thickness and strength of the sink in sea mollusks are different. Particularly durable and thick shell have shells - chitons living in a surf band. Explain what is the difference in the thickness of the shell in the mollusks?

2. Mollusc habitat. (Presentation, slides number 16-22)

3. External structure. (Presentation, slides number 23-29)

Dimensions
Color
Body departments
Sink

Students determine which of the sinks proposed by them are open-spiral, and which are hidimipral.

Decision of the biological problem (class task)

In some countries, for example in France, grape snails used in food are bred on special farms. It is noticed that for rapid growth of the snail to their main food-grape leaves, it is necessary to add a piece chalk. Explain why?

4. The formation of pearls. (Message of the student) (presentation, slides number 30-31)

Pearls, organogenic lime concrete, formed in the body of some bivalve marine and freshwater mollusks - pearls. Pearls traditionally refers to precious stones. They are products of anomalous growth of mantle melt. Pearls consist of calcium carbonate - aragonite mineral, in exceptional cases - calcite; They necessarily contain a konchioline - protein-type organic substance. Cells of the konchioline form the pearl frame - a thin mesh, in the small cells of which (not distinguishable by a simple eye) are deposited by microscopic crystals of aragonitis. The average chemical composition of pearls: CASSO Z91.72%, konchioline - 5.94%, water - 2.23%; Losses with calcination 0.11%.

The name "Pearl" occurred from the Chinese "Zhen-Zhu", transformed through the Starus "Zenchug". In Russia in 18-19 centuries. Pearls were often called Pearls (from him. Perlen and English. Pearl, derivative "Pearlmutr" -Sleck distorted by him. Perlmutter, "Mother Pearl").

The shape of the pearl is the rounded, often a drop-shaped or pear, ellipsoidal or incorrect, fancy ("baroque pearls"). The size from the first millimeters to the first centimeters (very rarely is larger). The "varietal" pearl reaches the size of more than 3 mm, "beads" - 3-2 mm, "pearl dust" - less than 2 mm. The largest pearl found in the Philippines in 1934, 16 cm and a mass of 6.4 kg, had an oval shape, dimensions 24

If the pearl is growing not in the mall of mollusk, but directly grieves the inner surface of the sink of the sink, then it does not have a pearl layer in the attachment site; Such pearls is called "blister", or "bubble pearls", and is less valued. Unlike round or baroque pearls, not requiring other processing, except drilling through holes, blister-pearls are usually treated for inserts into rings, earrings, bracelets and other decorations. Pearl coloring is diverse: white, pink, cream, black, bronze, brown or pastel shades of lavender, blue, yellow, green, pinkish-purple colors. In jewelry trading prefers pink, cream, white and black pearls. It is believed that the pearl binds its painting from the inner pearlescent layer of the shell, more precisely - from the part of the pearl layer, near which it was formed, i.e. The pearl color depends on the type of mollusk-owner. In addition, the pearl color affects the temperature and composition of water, the state of the health of the mollusk and even the character of food he digested.

Pearl is built of several thousand thin concentric layers of aragonitis and konchiolin. A peculiar irrigation shine, gentle shimmering overflows of iridescent colors on the surface of the pearls, who give it a unique charm, make up a special property of mature pearls "Orient", or "chandelier", for which it is mainly appreciated. This property is due to its multi-layer structure, reflection and refraction phenomena, diffraction and interference of light on a translucent surface of the pearl. Black pearl brilliance - metallic. Pearl hardness 3.5-4 (the same as the aragonite). The average density of natural pearls is 2.685.

Natural pearls are formed as a result of random inwards of the sink of an extraneous subject. It may be tiny sand or worm

However, many natural pearls in the context do not detect any trace of an extraneous stimulus. It is assumed that in such cases the kernel had an organic nature, but after the start of deposition of calcium carbonate decomposed, not leaving traces.

The most highly appreciated sea pearls "Oriental", less valuable - freshwater pearls.

In the USA in Iowa, there is a center for the manufacture of pearl buttons based on regular capture in the r. Mississippi and her tributaries of freshwater bivalve mollusks of the genus Unio. Their sinks serve material for buttons. This is a very time-consuming fishing. To find a pearl suitable for sale, dozens and hundreds of kilograms of shells must be opened.

The best pink and cream pearl in the world is mined in the Persian Gulf, where he grows in small pearls Pinctada Vulgaris. This mollusk is rarely larger than 8 cm in the diameter. Pearls, inhabitants of the North Coast of Australia, form beautiful silver-white pearls, larger than the mollusks of the Persian Gulf. The Australian pearl Pinctada Maxima pearl sometimes reaches in diameter 30-36 cm. The main business of pearls in Australia - collecting sinks on the mother of pearl.

Other famous spots of pearls - Sri Lanka, Venezuela (His pearls have found another Columbus), Tahiti, Mergui Archipelago in Myanmar and the California Bay in the United States. Each region is characterized by a pearl of a certain type (in particular, specific color). High-quality pearls from the Persian Gulf determines the maximum price level for any natural pearl.

The river pearls had once been found in England and Ireland; The Romans brought it from the British Islands. Now the mining of the river pearl is carried out only in Germany (Bavaria) and the United States. The northern and northwestern rivers of the European part of Russia have previously abounded by pearls. Pearls since ancient times appreciated in Russia; They were expanded by women's clothing and hats (sundresses, kokoshniki, etc.), the leaders of the clergy, and sometimes the robes of nobles, the salaries of the icons were decorated, replaces of handwritten church books, church utensils, etc. Particularly appreciated the scope (ie, round) pearls from the cafe (the ancient name of Feodosia in the Crimea) - Kafimsky (Great, Veli), which brought there from the east. In the big honor was pearls in ancient Rome. Pliny Elder (77 AD) placed it in the hierarchy of precious stones in second place after diamond and in front of Emerald. In the Medieval East, where the red stones were especially valued, the first place, naturally, was given to Rubin, the diamond and pearls followed (also in front of Emerald). Currently, natural pearls are among the most expensive jewelry stones.

Unfortunately, pearls are short-lived. After 150-200 years, the pearls "illness", i.e. Distens and cracks due to the drying of the konchiolin, losing its iris and losing, thus losing the main advantage of the jewelry stone. However, the pearls, which preserved their shine and beauty, despite the very solid age, are 300-400 years and more.

5. Internal structure. (Answer using an interactive circuit Disk "Multimedia allowance" Kirill's lessons and Methodius "Animals", lesson №11, page 26)

Decision of the biological problem (class task)

The salivary glands of some predatory bruhogs feeding with other molluscs contain free 2-4% sulfuric acid that makes it easier for them to extract food. How are the predatory shellfish use acid?

6. Reproduction and development of mollusks. (Presentation, slides number 42-43)

Demonstration of video news "reproduction of grape snails"

IV. Conversation with class about the origin of mollusks.

The origin of mollusks.

Apparently, the mollusks occurred from primitive ringed worms that switched to crawling along the soil. The abdominal side of the skin-muscular bag turned into a leg, due to the development of the protective shell, the support function of the agencies was lost, and it was reduced. The most primitive forms retain the traits of segmentation in the structure of the nervous, sexual and excretory systems. Further development of the Group is associated with a change in the methods of movement and nutrition and the evolution of the shell.

Name the common features of mollusks and ring worms.

Some important common features of mollusks and ringers

Bilateral-symmetric (monopoplastic) body.
Preservation in the lower clams of traces of metameric in the inner structure.
Secondary body cavity - whole.
The presence of a circulatory system, the overall direction of blood flow.
extraction system of metanephridial type.
The central nervous system consisting of a daddy and stilt of ganglia and nervous chain.
Spiral crushing eggs and a three-phophyl larva.

Name the signs of a high organization and the features of mollusks. Signs of a high organization and the features of mollusks.

Loss of body segmentation.
Separate part of the skin and muscular bag and leg formation.
The formation of outdoor protective and supporting shells - sinks.
The development of a multi-chamber heart.
The development of a gill system, the formation of lungs for gas exchange on land (in buchelichi).
Development within the type of diverse sense organs, centralization of the nervous system and the development of the brain (pharyngeal ganglia), especially in chasing.

V. Verification work.

Option number 1.

1. To mollusks living on land, belongs:

a) toothless; b) squid; c) grape snail.

2. Mollusk sink is formed:

a) the allocations of the mantle; b) sand and other particles that glued to the body; c) the discharge of the digestive glands.

3. Pershing vegetable food occurs in many mollusks:

a) using a stomach grater; b) the grater of the language; c) the grater of the small intestine.

4. Water current through mollusc siphons:

a) the difference in water pressure at the entrance and outlet; b) the movements of cilia mantle, gills, oral blades; c) swallow water.

5. To digestive glands of mollusks belong:

a) liver and pancreas; b) only liver; c) only pancreas.

Option number 2.

1. Sea molluscs include:

a) Squid and Caracatia; b) toothless and small pondovik; c) Octopus and peklock.

2. Mantle cavity is:

a) the inner space in the digestive tract; b) space between mantle and body; c) space between sink and mantle.

3. To remove there is no head, because:

a) Mollusks at all there are no headd off; b) toothless do not catch prey, but feeding passively; c) this is the only representative of bivalves who do not have a head body department.

4. The jet method of movement is characteristic:

a) for toothless; b) for mussels; c) for squid.

5. Lonanty breathing is characteristic:

a) for the blowers; b) for octopus; c) for a slug.

Option number 1	Option number 2.
1.V.	1.A.
2.A.	2.B.
3.B.	3.B.
4.B.	4.In
5 B	5.In

Vi. Homework.

Prepare a plan-abstract on the topic "Labor clamps. Features of the organization on the example of a small pond "

Solve Crossword:

Horizontal: 1. Freshwater bivalve mollusk. 2. Part of the sink snail. 3. A bivalve mollusk moved from the Black Sea to the European River. 4. Part of the body snail. 5. The common name of the buccular mollusks. 6. Ground snail. 7. Edible bivalve mollusk. 8. Freshwater bivalve mollusk. 9. Far Eastern marine mollusk. 10. Part of the shell. 11. Language of bucculent clams, armed with teeth. 12. Hole of the sink. 13. The protective formation of mollusks secreted by the cages of the mantle.

Vertically: 1. Brojon-legged mollusk. 2. Freshwater snail with a long breathing tube. 3. A tubule connecting the mantle cavity of bivalve mollusks with the environment. 4. Large ground tropical snail. 5. Small snail. 6. Mollusk, whose mucus is used to prepare the paint "Royal Purpur". 7. Fossil mollusk that has spiral sink. 8. Mollusk - pest of field and berry crops. 9. Two mollusk - the inhabitant of uncertic reservoirs. 10. Predatory mollusk destroying oysters. 11. Mollusk with poisonous glands and teeth. 12. Hellon Mollusk.

Municipal Autonomous Secondary Institution

"Beloev Central Secondary School"

Kudymkar District of Perm Territory

Abstract of the lesson on biology
in the 7th grade

"The overall characteristic of the type of mollusks"

Prepared

biology teacher

Rocheva Raisa Nikolaevna

from. Beloevo
2014

Subject: General characteristics of the type of mollusk

Class: 7

Type of lesson: studying a new material.

Purpose: Get acquainted with the features of the structure and life of animals belonging to the type of mollusks;

Tasks:

ABOUT brass

Give the overall characteristics of the type of mollusks;

AND touch the classification of the type of mollusk

Determine the complications of the organization of mollusks during evolution compared to other animals;

Identify the features of the origin of mollusks, the organization of their structure and livelihoods;

Developing

Develop the skill among schoolchildren to compare, summarize the facts studied;

Allocate the main thing in the text and record in the table.

Educational

Teach to appreciate the beauty of the surrounding world and raise the value attitude towards nature

Methods: Verbal, visual, explanatory-illustrative

Type and view of the lesson: lesson studying new material, talk time

Equipment: projector, computer, presentation, table.

Concepts (new):asymmetry, sink, pearl, leg, mantle, mantle cavity, grater (Radules), Liver, Light, Heart, Kidney, Okolosraid Bag.

I. E. tAP of motivation (self-determination) to educational activities.

Today's lesson Let's start with the epigraph:

"Sota random features, and you will see the world is beautiful!"
A. Block (slide 1).

II. E. tap update and trial learning action.

In the last lesson, we studied the topic?

Ring worms. Class of minority.

Who will write to the systematics of these animals on the board?

Name the aromorphosis of the ringed worms?

III . The stage of identifying the place and the causes of difficulties.

Now listen to interesting facts and look at the slides.

1. The biggest ever caught weighed about 340 kilograms. He was caught in Okinawa, Japan in 1956.

2. The oldest caught by man, according to scientists, he had age in the area of \u200b\u200b405 years, perhaps he was the oldest marine animals.

3. Age can be determined by the number of rings on the sink of the shell. Each ring differs from the previous features of food consumed during this period, the state of ecology, temperature and amount of oxygen in water.

4. The main type of food is plankton, which they are filtered out of the water.

5. The largest animal in the world length is more than 18 meters. They caught this representative of invertebrates in 1880 in New Zealand. The first mention of them dated 1555 year. They were called them at the time and the sprockets and the sea snakes, and in general people have refused to believe in their existence for a long time. Sports of Japan's scientists in 2007 were able to photograph for the first time these animals.

6. The story of pearls is associated with the history of mankind. Do not everyone know that pearls are the first of the most famous precious jewelry. For dozens of millennia BC, a primitive man in search of food accidentally found something beautiful, hidden inside the shell.

What animals say?

About mollusks

Name the subject of the lesson?

Type of shellfish.

Why mollusks? Let's turn to the dictionary. (Give the task Elvira S .: View from the dictionary, which means the word "mollusks").

Reads Elvira Startieva. (So \u200b\u200bsoft).

What do you know about mollusks? (Work orally, the teacher writes on the board: what would like to know).

Children speak.

What would like to know?

Children speak.

Know

IV . The stage of building an exit project from difficulty.

What sources will refer to the study of these issues?

Book, Internet, Dictionaries, Encyclopedia.

V. Stage to implement a built project.

How can one briefly state a new material in the notebook?

In the form of schemes, table.

Study the new material will be in groups by text in the textbook. Allocate the most important and record in the table. (Children, studying new material, fill the tables). (The work algorithm is issued).

Task for 1 group: Fill out a table.

Compared feature

Task for 2 groups:

Organs and system systems

Task for 3 groups: Fill out a table.

Organs and system systems

Task for 4 groups: Fill out a table.

Comparable signs

Task for 5 groups:disposable to the aromorphosis notebook and prepare output on the topic.

Vi. E. tAP of primary consolidation with progress in external speech.

We check the table: each group tells the information that was given in the table.

VII . The stage of independent work with self-test on the standard.

Task: Fill in the passes in the text.

Task for 1 group:

The body of mollusks consists of _______________________________________. Unlike mollusks, the body of the mollusks _______________________________.

Task for 2 groups:

The body of many mollusks is covered by solid ___________________________. Outside the body of mollusks is surrounded by a skin fold - ________________.

Task for 3 groups:

There is _______________________________________________________ between the body of mollusks and skin fold. The organs ________ Some mollusks are gills, other clams _____________ with the help of lungs.

Task for 4 groups:

The bloodary system of mollusks consists of _____________ and blood vessels. The nervous system of mollusks is represented by separate clusters ________________________. Authorities __________________ Mollusks serve paired kidneys.

VIII. . The step of inclusion in the knowledge and repetition system.

The task: choose the right statements (performed in pairs):

1. The body of mollusks consists of a torso and legs.

2. Some mollusks do not have sinks.

3. The nervous system of mollusks is formed by nerve trunks connected by jumpers.

4. Respiratory authorities - Zabra, from land representatives - lungs.

5. Blood system is closed.

6. All mollusks are vegetative animals.

7. Glossing bodies of mollusks - kidneys.

8. All mollusks are hermaphrodites.

The task is checked. Right answers:2, 4, 7.

The task: Write on the board systematics type mollusks.

Children guess that there is no class. From here, make the conclusion that in the next lesson we will get acquainted with classes like mollusks.

IX. E. tAP of the reflection of training activities in the lesson.

What did we want to find out in the lesson?

What did we manage to find out?

We answered the questioned question?

What are we going to do tomorrow?

What was the most important in the lesson?

Who wants someone to praise?

D / s: Paragraph 20. Make small messages: who did not know everything in the lesson, what did you want to find interesting facts with mollusks.

Literature

Konstantinov V.M. Biology: Grade 7: Textbook for students of general educational institutions / V.M. Konstantinov, V.G. Babenko, V.S. Kuchmenko: under. ed. prof. V.M. Konstantinova. - 4th ed., Act. - M.: Ventana-Count, 2011.- 304 C.: IL.

Under the general edition of the Doctor of Biological Sciences, Professor A.I. Heschevel Animals Prikamye: Tutorial. - Perm: "Book World", 2001.- 184 p.

1. What are the main signs characterizing mollusks? Make and sketch the structure of the structure of the brochonog mollusk, make the designation in the picture.

The body of mollusks in most cases consists of head, torso and muscular leg;

The torso is a skin-muscular bag, surrounded by an extensive skin fold - mantle;

The mantle cavity is formed between the mantle and the wall of the body, in which the respiratory authorities are formed, some of the senses, it opens a posterproof hole, kidney and sex glands;

The digestive system consists of anterior, middle and rectum;

In the throat, there is usually an organ, grinding food, - a grater with horny tarts located on it;

The circulatory system is unlocked (except for challenges of mollusks); The blood movement provides a two-chamber heart;

There are organs of vision, equilibrium, chemical sensitivity, touch;

Respiratory organs in the aquatic forms - gills, land - lungs; Present a specialized area of \u200b\u200bskin folds - mantle.

2. What is a mantle? What is its value?

Mantle - Fabric folds in mollusks surrounding the body. The mantle cavity is formed between the mantle and the body, in which there are some senses and where the rear-ground opening, kidney and sex glands are opened.

3. What is the sink? What are its functions? What chemicals form the main mass of the shell?

Sink is a protective formation that covers the body of mollusks. Sink, as a rule, is formed by the secretions of the mantle. It can be solid, less often double or consisting of several plates. The outer layer of the shell is formed by an organic rod-like substance, the inner - thinning plates of lime. The uneven reflection of the light from these plates give the inner surface of the sink pearlescent shine. In some clams, underdeveloped shell is immersed under the skin or disappears at all (slugs, cephalopod).

4. Describe the structure of the body of bivalve mollusks.

The soft body of mollusks in most cases consists of heads, torso and legs. On the head there are a mouth hole and sense organs. The body is a bag, its base is surrounded by an extensive skin fold - mantle. On the dorsal side, as a rule, a protective sink is provided by mantle. Thickened thanks to the muscles of the abdominal side forms various shapes of the legs: wide - crawling, wedge-shaped, similar to fins - for swimming, rounded - ascending, etc.

5. Discuss in the class of similarities and differences in representatives of different classes of mollusks.

In the process of resettlement on the planet, the mollusks were divided into a number of groups united in several classes. Among them are the buccular, bivalve and the most highly organized - cephalopod.

6. Make a table "Comparative characteristic of ring worms and mollusks" (work in small groups).

7. What do you think, what role are mollusks in nature? Give examples of mollusks living in your area.

Mollusks matter as a source of pearl and pearls. The most appreciated pearls of the sea pearl, found in the Red Sea, Indian and Pacific Oceans. Many sea bivalves are eaten, such as oysters, mussels, sea scallop, squid. Double mollusks - powerful natural water purify whether (bio filtrators). Eating weighted in water with organic substances and the smallest alive organisms (plankton), they pass through the mantle cavity a large amount of water, cleaning it.

8. Highlight the features of the body of mollusks associated with their lifestyle.

Key Features:

The body is deprived of segmentation, has two-way symmetry (bivalve and cephalopod) or asymmetrical (broxogne);

The body of the mollusks is concluded in the sink that protects the animal and the giving support for muscle attachment, in the bucculent mollusks of the sink is solid in the form of a cap or spiral turrets, in bivalves it consists of two sash, connected by an elastic bundle, most challenges of the sink have lost.

9. Make a divorced paragraph plan.

General characteristics of the external structure of mollusk type representatives;

The structure of the nervous system;

The structure of the senses;

The structure of the circulatory system;

The structure of respiratory bodies;

Structure of the digestive system;

The structure of the allocation bodies;

The value of mollusks;

Clay clamium clay (general class characteristic);

General characteristic of class bivalve mollusks;

Economic importance, representatives;

General Characteristics of the Channel Channel Challenge;