Mollusks are a group of invertebrate animals that includes more than a hundred thousand species various organisms, very different from each other in appearance, behavior, and habitat. In the following paragraphs of the article, you will discover 10 basic facts about mollusks, ranging from classification to the structure of the nervous system.
1. There are eight living classes of mollusks
- Pit-tailed ( Caudofoveata) are small, deep-sea animals that live in soft bottom sediments. These worm-like invertebrates lack the shell and muscular legs of other mollusks, and their bodies are covered with scale-like, limestone spicules.
- Sulcate-bellied ( Solenogastres), like pittails, are worm-like mollusks without a shell and have a flattened or cylindrical body shape.
- Armored ( Polyplacophora) - a class of flat mollusks, with a shell divided into eight parts and covering the upper part of the body; live in tidal waters along rocky shores around the world.
- Monoplacophora ( Monoplacophora) - deep-sea mollusks equipped with a lid-like shell (shell). They were considered extinct for a long time, but in 1952, zoologists discovered several living specimens.
- Bivalve ( Bivalvia) - a class of mollusks, representatives of which are characterized by the presence of a shell consisting of two parts (valves). They have no head, and their bodies are a wedge-shaped "leg".
- Spadefoot ( Scaphopoda) are molluscs that have long, cylindrical shells with tentacles extending from one end, which animals use to capture prey from the surrounding water.
- Gastropods ( Gastropoda) - the most diverse class of mollusks, including more than 60 thousand species of snails and slugs living in marine, freshwater and terrestrial environments a habitat.
- Cephalopods ( Cephalopoda) - the most developed class that unites octopuses, squids, cuttlefish and nautiluses. Most members of this group either lack or have a small inner membrane.
2. Shellfish are a very diverse group of animals.
Any group of animals that includes squid, oysters and slugs poses a challenge when it comes to developing general description. In fact, there are only three characteristics shared by all modern mollusk species: the mantle, the mantle cavity, and the paired nerve cords.
Apart from some exceptions, most mollusks can be characterized by the presence of a broad, muscular leg, as well as a shell (excluding cephalopods, some species of gastropods and primitive mollusks).
3. Most mollusks are bivalves and gastropods
Of approximately 100,000 known species mollusks, about 70,000 belong to the gastropod class and about 20,000 to bivalves, or 90% of the total. Across these two groups, most people perceive mollusks as small, slimy creatures equipped with calcareous shells (although the largest species of mollusks, the giant tridacna (weighing more than 200 kg), is a member of the class Bivalves).
Although snails and slugs from the gastropod family are eaten in many countries around the world (if you've been to French restaurants, you should know what we're talking about), bivalves are a more valuable source of food, including octopus, mussels, oysters and other underwater delicacies.
4. Octopuses, squids and cuttlefish are the most developed mollusks
Gastropods and bivalves may be the most common molluscs, but cephalopods (a class that includes octopuses, squid and cuttlefish) are by far the most advanced. These marine invertebrates have amazingly complex nervous systems that provide them with camouflage and even solve certain types of problems (for example, octopuses are known to escape from their tanks in laboratories, slide across cold floors, and climb into other tanks containing tasty bivalves).
If humans ever go extinct, it is likely that the distant, intelligent descendants of octopuses will become the dominant life form on earth, or at least in the ocean.
5. Naturalists put forward a fictional creature as the ancestor of mollusks
Because modern molluscs vary greatly in anatomy and behavior, tracing their exact evolutionary path is a major challenge. To make things easier, naturalists have proposed a "hypothetical mollusk ancestor" that displays most, if not all, of the features of modern molluscs, including the shell, muscular leg, and tentacles.
There is no evidence that such an animal did not actually exist. Experts generally say that mollusks evolved hundreds of millions of years ago from tiny marine invertebrates known as spirallings ( lophotrochozoan), but even this theory is subject to debate.
6. The clam's brain is wrapped around the esophagus.
The nervous system of mollusks, like invertebrates in general, is very different from the nervous systems of fish, birds, reptiles, amphibians and mammals. Some species of mollusks have clusters of neurons (called ganglia) rather than a true brain, while the brains of more advanced mollusks such as cephalopods and gastropods are wrapped around the esophagus rather than isolated in a hard skull.
Surprisingly, most of the octopus' neurons are located not in the brain, but in its tentacles, which can function autonomously even when separated from the body!
7. Two classes of mollusks went extinct
By studying fossil evidence, paleontologists have established the existence of two now extinct classes of mollusks. Rostroconchians - lived in the World Ocean approximately 530-250 million years ago, and may have been the ancestors of modern bivalves. Helcionelloida - lived 530-410 million years ago, and share many characteristics with modern gastropods.
Somewhat surprisingly, cephalopods have existed on Earth since the Cambrian period. Paleontologists have identified more than two dozen (much smaller and less intelligent) genera of cephalopods that roamed the world's oceans more than 500 million years ago.
8. Most shellfish are vegetarian
With the exception of cephalopods, molluscs are largely vegetarian. Terrestrial gastropods, such as snails and slugs, eat plants, fungi and algae, while the vast majority sea mollusks(including bivalves and other marine species) feed on plant materials dissolved in water, which they absorb by filtration. The most advanced cephalopods, they eat everything from fish to crabs and invertebrate counterparts.
Octopuses in particular have terrible table manners, injecting venom into soft-bodied prey or drilling holes in bivalve shells and then sucking out the tasty contents.
9. Shellfish have had a lasting impact on human culture.
As a food source (especially in the Far East and Mediterranean), shellfish have contributed to the development of human civilization in many ways. Cowrie shells (a family of small gastropods) were used as currency by Native Americans, and oyster pearls have been treasured since time immemorial. Another gastropod, murex, was cultivated by the ancient Greeks for its dye known as imperial purple. The cloaks of some Greek rulers were woven from long threads soaked in this dye.
10. Many species of shellfish are on the verge of extinction
The vast majority of mollusks live in the depths of the ocean, and are relatively protected from the destruction of their habitat and human predation, but the same cannot be said about freshwater and terrestrial species. Perhaps not surprisingly from a gardening perspective, snails and slugs are the most vulnerable to extinction, having been systematically destroyed by agriculture or suffering from invasive species carelessly introduced into their habitats.
Just imagine how easily the average domestic cat, which can easily catch nimble mice, can devastate an almost motionless colony of snails.
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Department of Science Education
INfinal certification work
Methodological developmentmuseum-pedagogical lesson
in the zoological museum on the topic« The amazing world of shellfish»
student of advanced courses
qualifications
"Theory and methodology of teaching (biology)"
Demeshchenko Irina Alexandrovna
GBOU secondary school No. 217 Krasnoselsky district
named after N.A. Alekseev
Saint Petersburg
2014
Introduction 3
"The Wonderful World of Shellfish" 4
Route sheet 12
Appendix No. 1. Instruction card " general characteristics type
Shellfish." 14
Appendix No. 2 Instruction card "Characteristics of the class Gastropods" 15
Appendix No. 3 Instruction card "Characteristics of the class "Bivalve" 17
Appendix No. 4 Instruction card “Characteristics of the Cephalopod class” 19
Appendix No. 5 Instruction card " Diversity of Gastropods" 22
Appendix No. 6 Instruction card “Diversity of Bivalves” 23
Appendix No. 7 Instruction card “Diversity of Cephalopods” 25
Appendix No. 8 Instruction card“The Legend of Murex” 27
Appendix No. 9 Instruction card"The Legend of Tridacnus" 28
Appendix No. 10 Instruction card “The Great Miracle of the Sea - Pearls” 29
Appendix No. 11 Instruction card “Gladyshevsky Nature Reserve” 30
Literature 31
Introduction
Textbooks and manuals on the subject are sometimes stingy with facts and boring, and biology is the science of life. Studying biology only in school lessons, without the opportunity to personally see the subject of study, without the ability to search for patterns and generalizations based on the study of natural objects, is unnatural. How to “shake up” the learning process, how to interest students?
One of the solutions, in my opinion, is to use both ready-made excursions to the zoological museum and excursions prepared by the teacher himself or a group of students who try on the role of a guide.
A museum excursion is a form of cultural and educational activity of a museum, based on a collective tour of the museum under the guidance of a specialist on a pre-planned topic and a special route. A special feature of a museum excursion is the combination of showing and telling with the dominant role of visual perception, which is complemented by impressions of a motor nature: inspection with different points view, at different distances.
Anyone who loves the museum, knows how to tell interesting stories, and strives for new knowledge can be a guide.
Thus, museum pedagogy is innovative technology in the field of personal education of children, creating conditions for the immersion of the individual in a specially organized subject-spatial environment.
I would like to offer one of the options for such a biology lesson in a museum.
A museum-pedagogical lesson in zoology on the topic “The Amazing World of Mollusks” can be held both on the basis of the Zoological Museum of the Zoological Institute of the Russian Academy of Sciences in St. Petersburg, and on the basis of the Zoological Museum of the St. Petersburg Academy of Postgraduate Pedagogical Education. The lesson is intended for 7th grade students.
During this lesson, children become researchers and travelers. Their task is to follow the route and complete tasks on the route sheet, using the exhibits presented in the museum and the information received.
Methodological development of a lesson on the topic "The amazing world of mollusks."
Preparing for the excursion.
Before the excursion, students are given the task:
Using additional literature and online resources to expand your knowledge on the topic being studied,
Compose, but do not fill out the table “Type of Molluscs” (name of the representative, class affiliation, significance in nature and human life).
Target:
· familiarize students with the department's exhibition malacology museum,
· create conditions for learning the diversity of representatives of the Mollusc type, their significance in nature and human life.
Tasks:
Educational:
· develop the ability to observe and recognize animals among museum exhibits;
· expand ideas about the features of the external structure of representatives of classes such as Mollusks;
· determine the significance of the type of Mollusks in nature and human life;
· deepen the knowledge gained earlier in class on the topic;
· formation of scientific thinking, mastery of scientific terminology,
· formation of students’ ability for self-development and self-education;
· development of search activity skills in a museum setting.
Educational:
· to develop practical skills;
· developing the ability to organize educational cooperation and joint activities with the teacher and peers; work individually and in a group;
· development of oral monologue speech;
· developing the ability to plan one’s activities, correlate one’s actions with planned results, and monitor one’s activities in the process of achieving results;
· developing the ability to establish cause-and-effect relationships, build logical reasoning, inference and draw conclusions;
· formation and development of ICT competencies.
Educational: respect for living nature.
Concepts:mantle, mantle cavity,byssal gland, ink gland, hermaphroditism, hemocyanin, filtration, siphon, shell.
Personal skills
· the formation of cognitive interests aimed at studying the type of Mollusks;
· formation of intellectual skills (to prove, reason, analyze, compare animals such as Mollusks).
Meta-subject skills
Cognitive:
· the ability to find similarities and differences between objects; conduct surveillance; transform information from one form to another.
Regulatory:
· the ability to complete an educational task in accordance with the goal and plan;
Communicative:
· the ability to adequately use verbal means for discussion and argumentation of one’s position (the ability to formulate a statement); ability to compare various points sight and find common decision; Ability to work together in a collaborative atmosphere.
Subject Skills
· development of skills to identify representatives of the Mollusca type;
· the ability to compare the characteristics of animals of the classes Gastropods, Bivalves, Cephalopods;
· ability to point general signs type Mollusks.
Materials and equipment: collection of mollusk shells, route sheets,instruction cards, tests,self-control sheets, natural objects.
Forms of activity: independent, group.
Methodical techniques:
teacher's story with elements of heuristic conversation at the base and using exhibits from the collection of the zoological museum
students' stories based on pre-prepared materials (advanced learning).
Lesson stages:
1. An organizational moment with an element of psychological adjustment to work.
2. Indicative and motivational - communication of the topic, purpose and objectives of the lesson. Updating the zone of optimal knowledge acquisition.
3. Formation of new knowledge (organization of educational activities of students).
4. Consolidation of knowledge.
It is advisable to begin the lesson with a general acquaintance with the department of the zoological museum dedicated to mollusks.
Excursion progress:
1. Organizing time.
2. Indicative and motivational.
You and I are in the Zoological Museum of the Russian Academy of Sciences (zoological museum of the St. Petersburg Academy of Postgraduate Pedagogical Education), where we will meet with a very unusual group of living organisms, but what their names are, I want you to guess for yourself.
Please listen to a short excerpt from M.E.'s fairy tale. Saltykov-Shchedrin “Crucian carp the idealist”:
“The crucian carp lies buried in the silt, and picks out microscopic shells from there for the sake of its food and reasons: “And it (the shell) is designed in such a way that it is impossible to swallow it. Draw water with your snout, and your craw is apparently invisibly teeming with shells "
Have you guessed what animals are hiding in shells?
The topic of our lesson "The Amazing World of Shellfish" . You will get to know interesting collection a variety of shellfish.You yourself will be the guide.I think you will like this unusual lesson.
3. Stage of formation of new knowledge.
Teacher's word.Collecting sea shells has a surprisingly long history. Human interest in shells, or rather, in their living contents, appeared about 120 thousand years ago. Of course, this cannot be called collecting in the sense as we understand it now in relation to, for example, coins or stamps: then people simply collected everything edible, including shellfish, in the shallow coastal waters. From those times, there remained “kitchen heaps” (in other words, scraps) of many shells, mainly mussels and oysters, which served as a significant addition to the diet of ancient man.
About 40 thousand years ago, people began to make jewelry (necklaces, combs, beads, pendants, earrings, belts) from shells for ritual ceremonies and everyday use.
Later, shells were the subject of trade, exchange, and in some places they served as money, a kind of freely convertible currency. At all Interest in sea shells as a collectible itself undoubtedly dates back to the era of the Great geographical discoveries XVI-XVII centuries, when a flood of overseas wonders poured into Europe, brought by sailors from long voyages to the shores of America, Africa and East Asia.
Naturally, in those days, collecting sea shells was available only to very wealthy people, since they sometimes cost a fortune and were sold at specially organized auctions.
Some shells have funny and sometimes dramatic stories associated with them.
Filigree epitonium shells(Epitonium scalare) consist of many non-joining whorls, attached to each other only at the points of contact of the concentric ridges. They were first described in the middle of the 18th century. from specimens found off the coast South-East Asia. Since this mollusk lives at great depths, it fell into human hands extremely rarely and was highly valued by collectors. The indigenous inhabitants of the coast where Epitonium lived received huge sums from Europeans for its shells. Clever and skilled Chinese came up with a way to deceive customers: they sculpted epitonium shells from rice paste. The fakes were so natural and skillful that the deception was not revealed immediately, only when the happy and unsuspecting owner of the “treasure” tried to wash the dusty shell, and it turned into mush.
Of course, the Europeans did not remain in debt. But this story already happened with the shell of another mollusk, whose name is the sacred chunk (Turbinella pyrum), and it lives off the coast of India. Probably, many have seen the image of the Hindu god Vishnu, but not everyone remembers that in one of his four hands he holds a sea shell - a turbinella. And not a simple one - right-handed (which is usual for shells of this type), but twisted in the opposite direction. Left-handed shells are rare - one in thousands of right-handed ones. Probably due to its rarity, it was depicted by an ancient artist and became sacred. Such shells were used in religious ceremonies not only in India, but also in the countries of Indochina, even in Tibet, Tuva and Kalmykia. Enterprising Europeans quickly figured out how to get rich from the sacred chunk. After all, they already knew shells, unlike turbinella, which are almost always left-handed. Thus, Busycon contrarium shells from the Caribbean became a source of income for Europeans for some time: gullible Indians bought these left-handed shells, considering them sacred.
"The amazing Japanese shell"(this is how the English epithet Japanese wonder shell is translated) is called Thatcheria mirabilis. And in the Latin name mirabilis means “amazing”, “amazing”. When you see it, it’s hard to believe that the perfect form, reminiscent of the biblical Tower of Babel, is a creation of nature, and not the sophisticated imagination of an artist. And therefore, the first specimen of this species, brought in 1879 from Japan to England by Charles Thatcher (the generic name of the shell was given in his honor), was considered anomalous for a long time. They thought that this was the result of a deviation in the development of some species. However, in the 30s. XX century Other similar shells were discovered, which convinced everyone that the original assumption was wrong.
Another shell that is still considered rare and highly prized by collectors is cone glory of the seas(Conus gloriamaris). For almost a century, only a few specimens of this species were known. At that time, such cones were found only on a small reef near the Philippines. And after the earthquake, the reef disappeared into the depths of the ocean. Everyone decided that the only habitat of the glory of the seas had disappeared. Prices for shells have skyrocketed. They say that one fanatic broke two cones from his collection so that the last one, the third, would become even more expensive. Fortunately, over time, the glory of the seas was discovered over vast areas from the northern shores of the Philippine archipelago (throughout New Guinea) to the atolls of Samoa and Fiji.
Collecting shells is not difficult; many experienced this hobby in childhood. Usually it all started with a trip to the sea or with a gift from relatives or friends who returned from warm coasts. The variety of shapes and shades of shells always amazes a person, but creating a more or less serious collection of shells that has scientific or educational value is not an easy task, requiring a collectible object. One of the main requirements for such collections is the preparation of accurate labels containing information about the location of the specimen (collection area, depth, type of soil, etc.). Sometimes it is important to indicate the date of collection, since some species are susceptible seasonal migrations and information about the time of year when the mollusks were found can increase knowledge about their biology. If the labels for collected shells are compiled properly, then even a small sample is of some scientific interest.
Memo to the collector
When compiling a collection of shells, do not forget that a shell is a house for a living organism and that by taking it away, we deprive the mollusk of life. Therefore, the following rules should become law for all shell collectors:
. When collecting live shellfish, never take more than you really need.
. always leave time to look through the specimens, turning over stones and corals, always return them to their original position - not only the mollusks that you collect live under them, but also other living organisms, if you destroy their home, they may die.
Group work.
I suggest you divide into 4 groups. Each group will receive its own route sheet and information card with the task. Your main task is to carefully study the information provided and examine the museum exhibits. And then tell us what you learned. This work takes 7 minutes. For advice, you can contact the museum staff.
Group work with route and information sheets (5-7 minutes)
Time is up. You need to answer clearly and quickly. Everyone listens attentively and independently fills in the empty supports that lie on your table.
Now let's listen to the tour.
1 group “Gastropods”,
Group 2 “Cephalopods”,
Group 3 “Bivalves”.
Group 4 “Protected mollusks of the Leningrad region”.
From each team, one student acts as a guide (3-4 minutes).
4. Consolidation of knowledge.
As the excursion progresses, you need to briefly record the data in itinerary sheets.
5. Summing up, conclusions, reflection, assessments, announcement homework.
Teacher.Today in class we met and made friends with mollusks. Now you are receiving a task from our friends (task on the interactive board).
Answer the test questions. Time - 2 minutes.
Test
(development of logical thinking)
A. From particular to general
1. Invertebrate, mussel, multicellular, bivalve.
2. Mollusk, squid, animal, cephalopod.
3. Gastropod, Cyprea, animal, invertebrate.
B. Fourth wheel
1. Featherweed, pond snail, cuttlefish, rapana.
2. Squid, argonaut, octopus, pond snail.
3. Luzhanka - snail, tridacna, jellyfish, octopus.
B. Terminology
1. Malacology (the science of mollusks).
2. Byssus (substance that forms the thread of the bivalve pinna)
3. Radula (tongue with a grater in the oral cavity)
4. Glochidia (free-swimming larva in bivalves)
D. Cognitive tasks
1. In case of danger, the body of the pond snail is pulled into the shell. However, some leeches crawl into the shell and suck out the soft parts of the pond snail's body. They eat pond snails and large fish and some birds. Draw a conclusion from the given facts.
2. It is known that the gastropod mollusk - the large pond snail - survives in an aquarium much better than the bivalves - pearl barley and toothless molluscs. State your hypotheses to explain this fact. ( The large pond snail breathes using its lungs. The barley and toothless fish are characterized by gill breathing, so they are more demanding of the amount of oxygen in the water. Unfortunately, it is not always possible to create a satisfactory oxygen regime in an aquarium for the normal existence of toothless and pearl barley. There may also be problems with feeding representatives of these mollusks, because... they can be fed only with the smallest aquatic inhabitants: bacteria, unicellular algae, ciliates).
Reflection.
Let's summarize our work. Did you enjoy the excursion?
Homework.
You have three options for homework. Choose and prepare for the next lesson the version of the task that you like best:
1.Learn the paragraph and make a crossword puzzle on the topic of the lesson.
2. Compose an interview - report “From the life of a mollusk”
3. Prepare projects “Let’s protect shellfish” in A4 format.
Lesson grades.
Route sheet “Shellfish”
Task No. 1. Fill out the table “Structural features of mollusk shells.”
|
No. |
Exercise |
Your observations |
|
Consider the shell of a bivalve mollusk: b) find its front (wide) end and back (narrow) end; c) find the convex part of the shell - the top; d) find curved lines - growth rings. |
||
|
Consider the shell of a gastropod: a) determine its shape, color; b) find the top of the shell and the opening - the mouth; c) count the number of revolutions of the shell. |
||
|
Compare the shells of two mollusks, establish similarities and differences according to the plan: 1. Form. 2. Coloring. 3. The presence of growth rings on the shell. 4. The presence of revolutions on the sink. 5. Shell strength. 6. The meaning of the shell. |
Task No. 2. Fill out the table:
|
No. |
Class Mollusca |
Representatives |
Adaptation to the environment |
Task No. 3. Fill out the diagram “The importance of shellfish”
Appendix No. 1
Instruction card No. 1.
General characteristics of the Mollusc type
Exercise:
The phylum mollusc includes three classes: slow-crawling snails (gastropods), relatively sedentary bivalves, and mobile cephalopods. The phylum has about 130,000 species.
The presence of a protective shell, mechanisms of external and internal fertilization, lungs and gills allowed mollusks to conquer both land and water. In mobile mollusks, the shell, which interferes with movement, is reduced.
The body of mollusks is soft, undivided, in most it is divided into a head, torso and leg. Under the shell there is a fold of skin - the mantle. The circulatory system is not closed, blood pours into body cavities (lacunae). The capillary network is lost.
The respiratory organs of most aquatic mollusks are represented by gills. Terrestrial forms breathe using the lung. Excretory system has a structure similar to annelids. The nervous system of the nodal type, nerve ganglia, are located in different parts of the body: head, leg, torso and interconnected nerve trunks. The sense organs of mollusks are varied and often complexly arranged.
Most mollusks are dioecious, but some are hermaphrodites. For many, fertilization is internal. The development of the most ancient mollusks is carried out with transformation - they retain a planktonic dispersal larva, swimming with the help of cilia. In more advanced forms, development is direct (cephalopods).
Appendix No. 2
Instruction card No. 2
Characteristics of the Class Gastropods.
Exercise:study the information provided. Tell us what you learned.
Gastropods (snails, slugs). The length varies from 1-3 mm to 30-60 cm. The body is clearly divided into three sections: the head, leg and torso, which is enclosed in a solid shell. Its height ranges from 0.5 mm to 70 cm.
Most often, the shell of gastropods has the form of a cap or spiral; only representatives of the 1st family develop a shell of 2 valves connected by an elastic ligament.
If in a spirally twisted shell the whorls are located in the same plane, then it is called placospiral. If the revolutions lie in different planes, then a turbo-spiral shell is formed.
In addition, shells differ in the direction of the spiral turns. If, when looking at the top of the shell, they twist clockwise, then it is a right-hand twisted shell; if they twist counterclockwise, then it is a left-hand twisted shell.
In some gastropods, such as cyprians and volutes, the last whorl of the shell is very wide and completely covers all previous ones. In this case, the shell is called cryptospiral, or involute. If all whorls of the shell are visible, then it is called open-spiral, or evolute.
Sometimes the shell is equipped with a lid located on the dorsal side at the back of the leg (for example, in lawns). When you pull your leg into the shell, the lid tightly covers the mouth. In some species that have switched to a swimming lifestyle (for example, pteropods and keelfoots), there is no shell.
Shell reduction is also characteristic of some land gastropods living in soil and forest litter (for example, slugs).
On the head of gastropods there are usually 1-2 pairs of tentacles and eyes. The mouth is on the underside of the head. It has a powerful tongue covered with a hard chitinous grater, or radula. With its help, mollusks scrape algae from the ground or aquatic plants.
In predatory species, a long proboscis develops in the front part of the body, capable of turning out through an opening on the lower surface of the head. In some gastropods (e.g., cones), individual teeth of the radula can protrude from the mouth opening and are shaped like stylets or hollow harpoons. With their help, the mollusk injects poison into the victim’s body.
Some predatory gastropod species feed on bivalves. They drill into their shells, secreting saliva containing sulfuric acid.
The respiratory organs of the vast majority of gastropods are gills. In some species they are located in the front part of the body and point their apex forward, in others they are located in the right rear part of the body and point their apex backward. In some gastropods (for example, nudibranchs), true gills were reduced. As respiratory organs they develop so-called. cutaneous adaptive gills.
In land and secondary aquatic gastropods, a special organ of air respiration is formed - the “lung”. It is a section of the mantle cavity, the walls of which are penetrated by a dense network blood vessels. Oxygen from entering lung of air diffuses through its thin walls, entering the blood. For all lung molluscs great value has cutaneous respiration.
Among gastropods there are both dioecious and hermaphrodite species. Fertilization is always cross-fertilization, development, as a rule, with metamorphosis. Direct development is observed in all land, freshwater and some marine gastropods.
A significant portion of gastropods are hunted for their meat, beautiful shells, and mother-of-pearl.
Appendix No. 3
Instruction card No. 3
Characteristics of the class Bivalve
Exercise:study the information provided. Tell us what you learned.
Bivalves, a class of mollusks of the testate subtype. Dimensions range from a few mm to 1.4 m, weight can reach 200 kg (for example, in tridacna).
The shell consists of two valves connected on the dorsal side by a flexible conchiolin strand - a ligament. The valves are most often symmetrical, but in some species their asymmetry is observed. On the back side of the valves, most bicuspid valves have teeth and grooves that form the so-called lock. Depending on the shape and size of the teeth, the lock can be equal-toothed or hetero-toothed. Some species (eg, toothless) are characterized by a lockless shell. The closing and closing of the valves of a living mollusk occurs as a result of the work of special closing muscles. IN in rare cases the shell may be partially (e.g. shipworms) or be completely reduced.
The shell is secreted by the mantle and consists of three layers. The outer or conchiolin layer is formed organic matter conchiolin, middle, or porcelain - crystals of calcium carbonate, oriented perpendicular to the longitudinal, and inner, or pearlescent - crystals of calcium carbonate, oriented parallel to the longitudinal axis of the mollusk body.
Shell growth occurs along the edge of the mantle, which is why concentric lines are visible on the valves. From them, as from the annual rings of trees, one can judge the growth rate and living conditions of specific individuals. If a foreign particle gets between the mantle and the shell valve, then nacre begins to be deposited on its surface in concentric layers. As a result, a pearl is formed, which grows as the mollusk itself grows.
Unlike other mollusks, bivalves have a completely reduced head. This is due to a sedentary or sedentary lifestyle. The wedge-shaped leg is used for digging into the ground.
Some bivalves living in the coastal or intertidal zone (for example, mussels) develop a special byssal gland. It secretes a secretion that hardens in water in thin threads. With their help, the mollusks are securely fixed to the substrate. Sometimes (for example, in oysters) the leg is completely reduced. Some species are able to move using legs or shell flaps (for example, scallops).
The inner surface of the mantle is covered with ciliated epithelium. The movement of its cilia creates a flow of water in the mantle cavity. The edges of the mantle can be free, or they can grow together, forming openings for the leg and two siphons located in the back of the shell. Through the lower, or gill siphon, water penetrates into the mantle cavity, and through the upper, or cloacal siphon, it is removed from the body.
The respiratory organs are the gills located in the mantle cavity. Only in septatebranchs did they lose their respiratory function and turned into small transverse partitions separating the area of the mantle cavity in which gas exchange occurs.
About 20 thousand species, divided into three superorders: protobranchials, branchials and septiobranchs. Marine and freshwater forms, widely distributed in the World Ocean and various fresh waters. They live on the bottom from shallow waters to maximum depths.
By type of nutrition, they are biofilters that play an important role in the biological purification of water. Some species are indicators of the cleanliness of water bodies. Many bivalves (mussels, oysters, scallops, pearl mussels, etc.) are objects of fishing and aquaculture. They are harvested and bred for valuable food products, as well as pearls and mother-of-pearl.
Appendix No. 4
Instruction card No. 4
Characteristics of the class Cephalopods
Exercise:study the information provided. Tell us what you learned.
Cephalopods- squids and octopuses are the most highly organized mollusks. The length with tentacles ranges from 1 cm to 5 m, and giant squid reaches 18 m. The body shape is very diverse and depends on the lifestyle of the mollusks.
Inhabitants of the water column, which include most squids, have an elongated, torpedo-shaped body. Benthic species, among which octopuses predominate, are characterized by a sac-like body. In cuttlefish living in the bottom layer of water, the body is flattened in the dorsoventral direction. Narrow, spherical or jellyfish-like planktonic species of cephalopods are small in size and gelatinous. T spruce
The body of cephalopods consists of a head and a trunk. Large eyes are located on the sides of the head. Among invertebrates, cephalopods have the most complex eyes, not inferior in complexity to the eyes of vertebrates. Cephalopods have developed not only the ability to see in stronger or weaker light, but also accommodation. True, it is achieved not by changing the curvature of the lens, as in a person, but by bringing it closer or further away from the retina.
On the head around the mouth opening there are tentacles that are part of a modified leg (hence the name). The vast majority of species have powerful suckers on their inner surface. Only nautiluses have relatively short tentacles, the number of which can reach 90, that remain smooth. Cuttlefish and squids develop 10 tentacles, 2 of which (catching ones) are very long, with suckers at the extended ends. Octopuses have 8 long, completely identical tentacles.
The other part of the leg turns into a funnel, which plays an important role in movement. It grows to the ventral side of the body, opening at one end into the mantle cavity, and at the other into the external environment. The mantle cavity in cephalopods is located on the ventral side of the body. At the junction of the body and the head, it communicates with the external environment through a transverse abdominal opening. To close it, in most cephalopods, paired semilunar fossae are formed on the ventral side of the body. Opposite them, on the inner side of the mantle, lie two hard tubercles reinforced with cartilage, the so-called. cufflinks As a result of muscle contraction, the cufflinks fit into the semilunar recesses, tightly fastening the robe to the body. When the abdominal opening is open, water freely penetrates into the mantle cavity, washing the gills lying in it. After this, the mantle cavity closes and its muscles contract. The water is forcefully pushed out of the funnel lying between the two cufflinks, and the mollusk, receiving a reverse push, moves forward with the rear end of the body. This method of movement is called reactive.
In the vast majority of modern cephalopods, the shell is vestigial and hidden under the skin. Only nautiluses retain an external, spirally twisted shell, divided into internal chambers. In cuttlefish, the shell, as a rule, has the appearance of a large porous calcareous plate. Only Spirula retains a spirally twisted shell hidden under the skin.
In squids, only a thin horny plate is retained from the shell, stretching along the dorsal side of the body. In octopuses, the shell is almost completely reduced and only small crystals of lime carbonate remain. Female argonauts (one of the species of octopuses) develop a special brood chamber, shaped very much like an external shell. However, this is only an apparent similarity, since it is secreted by the epithelium of the tentacles and is intended only to protect developing eggs.
All cephalopods are predators and feed on a variety of crustaceans and fish. They use tentacles to capture prey, and powerful horny jaws to kill them. They are located in the muscular pharynx and resemble the beak of a parrot. 1 or 2 pairs open into the pharynx salivary glands. Their secretion contains hydrolytic enzymes that break down polysaccharides and proteins. Often the secretions of the second pair of salivary glands are poisonous. The venom also helps immobilize and kill large prey.
Immediately before the anus, the duct of the ink gland opens into the lumen of the hindgut. It secretes a dark secretion, a small amount of which can cloud a large amount of water. Cephalopods use it to escape from predators.
One of distinctive features cephalopods is the presence of an internal cartilaginous skeleton. Cartilage, similar in structure to the cartilage of vertebrates, surrounds the head cluster of ganglia, forming a cartilaginous capsule. Branches extend from it, reinforcing the eye openings and balance organs. In addition, supporting cartilages develop in the cufflinks, base of the tentacles and fins.
All cephalopods are dioecious animals; Some of them have well-defined sexual dimorphism. Fertilization is external-internal and occurs in the female’s genital tract and in her mantle cavity. Some species take care of their offspring by bearing and protecting developing eggs. Development is direct.
About 650 modern species, belonging to 2 subclasses: nautiloids and coleoids. There are much more extinct species - about 11 thousand. They belong to 3 subclasses: ammonites, belemnites and bactrites.
Modern cephalopods are widespread in all seas (except desalinated ones). They live in the water column and at the bottom. Despite the fact that they are all predators, they often themselves serve as food for many fish and marine mammals. Some cephalopods are edible and are subject to commercial fishing.
Appendix No. 5
Instruction card No. 5
Diversity of Gastropods.
Representatives of the seas:
A) CIPREA.
Porcelain snail, shell - cowrie,
served as a monetary unit in the Pacific and Indian Ocean basins until the 20th century, and some peoples of Oceania still use it.
b) RAPANA.
Until 1974, it was known only in the Seas of Japan and the Yellow Sea, but, once in the Black Sea, it quickly multiplied. Being a predator, they destroyed a large number of commercial shellfish - oysters, mussels, scallops. Now, where these commercial shellfish are bred, i.e. in oyster parks, they must be fenced off from the sea ( collection of rapana shells).
V) MUREX or purple snail.
A very beautiful mollusk shell. In 1876 in France during construction railway An ancient burial site was found. Along with the people were weapons, tools, household items and...a necklace made of sea shells. Murex received its second name because a purple gland is secreted into the mantle. WITH ancient times Purple snails were used to produce purple dye. 1.5 g of purpura must be prepared to prepare 12 thousand murexes. Fabric dyed with this paint is very expensive, in modern money - $112,000.
Appendix No. 6
Instruction card No. 6
Diversity of Bivalves.
Representatives of the seas:
A) MUSSEL, OYSTER, SCALLOP
These are commercial shellfish. They create special farms, parks, and plantations for the cultivation of commercial shellfish. Clusters mussels called banks . Oysters are not only used as food product, but its shell is also used in the manufacture of artistic products. Buttons and jewelry are made from scallop shells. Except commercial value, they play a big role in nature: by filtering water to obtain food, they clean it of pollution. About 200 cubic meters of water are filtered per day. Serve as food for many animals, i.e. participate in the food chain.
b) PEARL.
The very name of the mollusk makes it clear what they are extracting - pearls, which are formed in a shell from a grain of sand. Pearls come in different sizes: from the smallest grains to a pigeon egg. The world's largest pearl weighing 450 carats (90 g) is kept in London. Pearls are short-lived: after about 150 years, they break down and turn to dust.
V) TRIDAKNA- giant clam.
It stands out among bivalves for its size. Its length is 1.5 meters, weight is about 200 kg, of which the soft part is 30 kg, and 170 kg is the shell. Tridacna lives among corals in the Indian and Pacific Ocean. The muscles that close the valves of the giant tridacna have enormous strength. You can open the shells of a living shell using a crowbar. Tridacnas are very dangerous for divers and pearl hunters. A person who accidentally inserts a leg or arm between the valves of a mollusk may die in the grip of a tridacna if he is not immediately helped. Since ancient times, tridacna shells and meat have been used by the peoples of Oceania - the Polynesians. Axes, fishhooks, etc. were made from shells. Now tridacnas are decorations for yards and gardens. It can also form a pearl, but has no jewelry value. Can form a mass of 7 kg. In New York, one jeweler had pearls on display in the window that had a mass of 6 kg 350 g, a length of 23 cm, and a thickness of 14 cm, irregular shape, i.e. almost the size of a human head.
G) PEARL, TOOTHLESS, PINNA.
Buttons were made from pearl barley and toothless shells. In Venice they can offer stockings, gloves and lace woven from silky fiber. There are mollusks that secrete a special substance byssus, with the help of which they are attached to underwater objects. These threads are strong and silky - up to 30cm long and form this thread - Pinna. There are mollusks whose shells were used as construction material: roofs and glass made of shells ( shell collection).
Appendix No. 7
Instruction card No. 7
Diversity of Cephalopods.
Representatives of the seas:
A) SQUID.
The inhabitant of the open sea is an excellent swimmer; he can rush underwater at the speed of a train - about 50-60 km/h. The squid is a predator, feeds mainly on fish and swims thousands of kilometers behind schools of fish. Having overtaken the prey, the squid grabs it with its long hunting tentacles, holds it near its mouth with the remaining tentacles and bites off a piece with its sharp horny jaws. Then the food is ground in the throat using a special grater - a radula. The squid cannot swallow the prey whole or even in pieces due to its narrow esophagus. The squid has very well developed sensory organs, especially the eyes, which in complexity can compete with the eyes of an owl, cat and man. The squid eye has a cornea, iris, lens, vitreous body and retina. The lens is round, so focusing the eye to look at objects located at different distances is done by moving it away or bringing it closer to the retina (as happens in a camera), and not by changing the curvature of the lens, as in mammals. Therefore, by the way, squids cannot be nearsighted or farsighted ( student's story)
b) OCTOPUS.
There are eight tentacles similar to each other on the head, with the help of which these mollusks can move along the bottom “on tiptoes,” that is, at the very tips of the tentacles extended vertically downward. In critical situations, octopuses, like squids, move in a reactive manner and can reach speeds of up to 15 km/h. The octopus has a horny beak. With its help, he makes a hole, for example, in the shell of a mollusk and lets toxic saliva in, which relaxes the muscle that closes the shell. The octopus also has a grater in its throat that grinds food. But the most amazing thing about the octopus is its highly developed brain, which has a rudimentary cortex. Consisting of approximately 170 million nerve cells (for comparison, the crab's nervous system contains approximately 100 thousand nerve cells), it is divided into many lobes, each of which performs its own function. More than half of the nervous tissue of the brain is located in the optic lobes. Octopuses are the most “smart” among all invertebrates. They are trainable, have a good memory, and recognize geometric shapes. They recognize people and get used to those who feed them. The octopuses that lived at the Naples station became completely tame. They knew the watchman by sight and loved him very much. If he extended his hand to them, the animals would wrap their tentacles around him and gently stroke him. However, large octopuses - and their total length (with tentacles) can reach 5 m - are dangerous, and the main danger is not the strong tentacles of large octopuses, but their poisonous saliva, which has a paralyzing effect on prey. One day, an employee of the California Aquarium was “bitten” in the palm by a small octopus. The first night after the bite, his hand swelled so much that the joints were no longer visible. The tumor subsided only after four weeks. Signs of the disease resembled symptoms snake bite. Small spotted blue octopuses live off the coast of Australia and Japan. Their bite can even be fatal to humans. . There are octopuses that lead sedentary lifestyle life, because have shells.
V) CUTTLEFISH.
Black soup was famous in Ancient Sparta. They prepared it as follows: they took cuttlefish, gutted it, but did not touch the ink sac. So they cooked it together. The ink gave the stew not only a brown color, but also a unique flavor that was highly valued. In Spanish and Italian cookbooks you can find all kinds of recipes for cooking cuttlefish and octopus. An example is octopus in chocolate or cuttlefish in milk. Usually they eat stewed octopus with new potatoes, garlic, cloves, and bay leaves. Canned cuttlefish in their own ink are prepared in Portugal and exported for sale abroad. In Japan and China they are eaten in all forms - raw, dried, pickled, baked, fried, boiled. The fat is rendered from the entrails, and the pomace is used to feed the chickens.
Appendix No. 8
Instruction card No. 8
"Legendand about murex."
In ancient times, Phenicia was ruled by King Tire. His only friend and obligatory companion on morning walks was a huge white dog. The king and his pet walked along the seashore, Tyr thought about his daily affairs, and the dog frolicked: playing with the waves, bringing objects picked up on the shore to his owner. One day he returned carrying a shell in his teeth murex. His snow-white fur on his face and chest was covered in blood. The king was afraid for the health of his pet and began to examine him, but did not find the slightest scratch. The king guessed that the mollusk shell was to blame for everything; it contained some kind of paint. Thus, according to legend, purple was discovered, to which the word divine was added. Indeed, the paint was extremely expensive, only emperors and very rich people could use it, but it was worth it - it was the first bright dye that did not fade in the air for a long time.
Appendix No. 9
Instruction card No. 9
The legend of tridacnis - the largest bivalve mollusk
When in the arms of the abyss
The diver will perish without return,
What's the use of arguing about the reason?
Powerless words are a waste.
Where schools of colorful fish swarm,
Where the shark's gaze is empty and gloomy,
He's there, diving for pearls,
Tridacna valves captured.
This tragic plot in various variations is quite widespread in the East. He talks about the following: on his wedding day, a young man (usually a prince), wanting to give a gift to his bride (of course, a dazzlingly beautiful princess), goes to the seashore. In a treasured place, where pearl mussels live, he dives to get a pearl worthy of the beauty of his beloved.Time passes, the beginning approaches wedding ceremony, but the groom is still not there. The bride is in grief, the relatives are in anxiety, everyone is rushing along the seashore, trying in vain to shout above the surf and at least hear something in response. Finally, daredevils begin to search the bottom and coral reef oh, woe! they find the body of a drowned prince, whose leg (or arm) is clamped by the flaps of a giant Tridacna.
Really, one of the Tridacni species - champion among mollusks in size. This is Tridacnagigas, which can reach almost one and a half meters in length and weigh almost 300 kg.The closing muscles of Tridacna are brought together and form, as it were, one muscle, so their strength is so great that the slammed doors cannot be opened even with a large crowbar. You need to insert a knife through the byssus hole and cut the muscle. So the question arises: is this story about the unfortunate prince a legend?
Appendix No. 10
Instruction card No. 10
The great miracle of the sea is pearls.
They say that the Egyptian queen Cleopatra once drank a precious pearl dissolved in wine vinegar. In ancient times it was believed that this was the surest way to preserve beauty and eternal youth. Cleopatra's experiment remained unfinished, because having suffered defeat in the fight against Rome and wanting to avoid shame, Cleopatra committed suicide by allowing herself to be bitten poisonous snake. But, in fact, what is this pearl, to which such wonderful properties were attributed?
There are many legends about its origin. According to one of them, pearls are morning dew that has fallen into a shell and frozen in it. We find mention of this, for example, in the famous ancient Indian poet Kalidasa in the poem Malyavik and Agnimitra (see epigraph by R.B.).
According to another legend, pearls are the tears of the beautiful Sita, the wife of the beautiful prince Rama.The evil demon Ravana Dashagriva (Ten-Headed) kidnapped Sita and, when he carried her in a boat across the sea, Sita's tears fell into pearl shells and gave birth to pearls. The great Indian epic Ramayana is dedicated to the struggle of Rama with Ravana for the liberation of Sita. The great Persian poet Nizami in the poem Seven Beauties (this is the 12th century) writes: Vyborg region lacustrine-glacial plain and lower sea terrace and Gladyshevka.
Salmon are released in places where the pearl mussel lives, since these are organisms that live in symbiosis (pearl oyster larvae live on the gills of salmon). In 2009, more than 20 thousand salmon fry were released into the watercourses of the reserve.
The Gladyshevsky reserve is the only habitat in the Leningrad region for the pearl mussel, a mollusk listed in the Red Book of the Russian Federation. It is strictly confined to cool, oliotrophic waters, and its habitat has declined sharply due to water pollution and eutrophication. In addition, the pearl mussel cannot live in reservoirs where there are no salmon fish. Its larva lives exclusively on the gills of salmon. refers to
2. Methods of historical and local history work at school: A manual for teachers / Ed. N.S. Borisova. - M.: 1982.
3. Museum pedagogy: From the experience of methodological work/Ed. Morozova A.N., Melnikova O.V. - M.: 2006.
4. New pedagogical and information Technology in the education system/Ed. Polat E.S. - M.: 2000.
http://www.naturconserv.org/
photo:Art
In living nature, mollusks are found almost everywhere - they are found in the thickness of ocean waters, high in the mountains, in salty and fresh water, on the ground and underground. They don't live only in sandy deserts and in snow cover.
The diversity of the habitat explains that mollusks differ from each other in body structure, its color and shape, methods and speed of movement and other features.
photo:jacinta lluch valero
But despite this, they have some common features: The mollusk consists of a head, body and legs. Most species are “equipped” with an external shell, which consists of protein substances and calcium carbonate. The shell plays a protective function - the mollusk hides in it at the slightest danger. It can be single or double-leafed. The body of the mollusk, like the shell, in most individuals is a spiral.
photo: divemecressi
The internal organs of mollusks are located in the body; in some species they are shifted to the leg. There are mollusks that do not have a head - it disappeared as unnecessary. The absence or presence of eyes, tentacles, the shape and size of the shell, the location of the internal organs - all this depends on the method of evolution, habitat, and nutrition of certain species of these invertebrate animals. It should be noted that mollusks are the first animals to have a liver.
photo: Martin LaBar
The first fossil mollusks belong to Cambrian period. Their ancestors are considered to be annelids, which have external segmentation. At the beginning of their evolution, cephalopods predominated, later bivalves and gastropods appeared. Modern scientists pay special attention to the study of the evolution of mollusks, which can be traced from preserved shells. This makes it possible to understand the developmental features of not only invertebrates, but also the rest of the animal world, because mollusks are an important component of the diet of fish, birds and mammals.
photo:Art
Today, there are seven classes of mollusks. The most popular of them are gastropods, bivalves and cephalopods.
Gastropods- one of the many species that live literally everywhere. These are aquatic and land snails. Moreover, in aquatic gastropods, the respiratory organ is the gills, while in land animals they are transformed into lungs, which allows the snails to be independent of the reservoir and live a full life on land. Bivalve mollusks are difficult to confuse with other species - they have a characteristic shell consisting of two closed valves. The body of the mollusk is enclosed between the valves. At the slightest danger, the doors slam shut, but in the normal state they are slightly open. Bivalves live in aquatic environment, both in salt and fresh water at different depths.
photo:Art
Cephalopods are considered the most “intelligent” representatives of this animal species. Cephalopods have good memory and a very large brain. They are found only in water - these are squids, cuttlefish, octopuses. Such mollusks can actively move thanks to tentacles equipped with special suction cups.
Other classes of mollusks are less common in wildlife.
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Ecology
In the depths of the sea, you can sometimes find incredible creatures that hide at impressive depths and which not everyone manages to meet. Some of the most interesting creatures oceans - animals such as mollusks.
There are more than 150 thousand species (of known ones), and every year zoologists add new ones to this list unique species. We invite you to learn about amazing mollusks, some of which were discovered quite recently.
1) Angelfish
We probably wouldn't be surprised if sea angels will find themselves in the same family of living beings as the mythological sirens. They are called angels, although in fact they are predatory sea snails. This special representative (pictured), which was called Platybrachium antarcticum, “flies” in Antarctic waters, hunting pteropods (another type of snail).
2) Armadillo snails
There is no other snail that is clad in such strong armor. Meet the lepidopus species Crysomallon squamiferum, which was discovered in a hydrothermal vent in Indian Ocean. The multi-layer structure of the shell is similar to skillfully made armor, which seems to be made of synthetic material.
3) Bioluminescent octopus
One of the few eight-legged animals that emit bioluminescence, that is, glow, the octopus species Stauroteuthis syrtensis was discovered at a depth of about a kilometer in the Gulf of Maine. Photophores (luminous organs) are used by the octopus to deceive prey, which swims directly into the predator's mouth.
4) Snail "Flamingo tongue"
This snail species Cyphoma gibbosum received such a strange name due to its bright spotted color. Only the soft tissues of this snail are painted, and its shell is plain. She hides in it in case of danger.
5) Hell Vampire
The hellish vampire is a cephalopod that can be found in Monterey Bay off the coast of California, however, if you descend to an impressive depth. Despite the name, this mollusk is not scary at all.
6) Eared octopus
Octopus genus grimpoteuthis found in the Mid-Atlantic Ridge region. These octopuses are sometimes called "eared octopuses" because of their ear-like fins that they move as they move.
7) Nudibranch "Golden Lace"
Resembling a snail without its shell, this nudibranch is famous for its bright and beautiful colors. This is a creature of the species Halgerda terramtuentiss was discovered in the northwestern part of the Hawaiian Islands.
8) Snail from a hydrothermal vent
Another inhabitant of hydrothermal springs, a snail of the species Alviniconcha, was discovered in the area of the Siyo seamount near hydrothermal vent Tokyo. This the only representative kind that was discovered.
9) Jeweled Umbrella Squid
This unusual squid species Histioteuthis bonnellii lives at a depth of about 1.5 kilometers or more in the Mid-Atlantic Ridge region. Unfortunately, due to the fact that this creature lives at impressive depths, it has been little studied.
10) Octopus from Lizard Island
Another striking representative of the group of mollusks, the Lizard Island octopus, was recently discovered in the Great Barrier Reef island area off the coast of Australia.
From March 7 to May 14, 2006, the State Darwin Museum, the State Historical Museum, the State Central Museum of Musical Culture named after. M.I. Glinka and the Zoological Museum of Moscow State University present the exhibition “The World of Mollusks and the World of Man.”
Mollusks appeared on our planet a very long time ago, almost 500 million years ago. Well-preserved shells of fossil mollusks after millions of years amaze us with a variety of shapes and sizes. But their descendants are immeasurably more interesting. From octopus to grape snail, from the seabed to ours own dacha- the world of mollusks is closely connected with the world of people.
Mollusks have been familiar to man since ancient times. The tribes that settled on the shores of the ocean used their shells as their first money. From ancient times, people obtained mother-of-pearl from some mollusks, and from others - purple, the dye that was used to dye the togas of emperors in Rome. One of the species of sea mollusks received the well-deserved name “the greatest disaster of ships” - it was the one that destroyed the ship of Christopher Columbus. Edible snails were bred in Britain by the builders of Stonehenge, and nowadays octopuses and squid are on the menu of gourmets around the world. Modern scientists call shellfish “the food of the future.”
This and much more is covered in a new exhibition opening at the Darwin Museum. The exhibition features shells and products made from them - jewelry, boxes, decorative panels. The evolution of the phylum Mollusca is illustrated by fossil specimens. One of the pearls of the exhibition is a volume of the 16th-century encyclopedia of animals, among the pages of which museum staff recently discovered golden threads of the byssus of the pinna mollusk. In the past, they were used to weave “shell silk” - an expensive and very beautiful fabric.
Many celebrities were fond of collecting shells: US President Lincoln, writer Edgar Poe, Japanese Emperor Hirohito, poet Pablo Neruda, and in Russia - naturalist and philanthropist Pavel Grigorievich Demidov, whose collection miraculously survived the fire of Moscow in 1812 and is now stored in the Zoological Museum of Moscow State University. The exhibition presents interesting examples of Demidov's collection. The Zoological Museum also provided the famous “Glory of the Seas” cone for the exhibition. Three copies of this beautiful shell were once purchased by a fanatic collector and two of them were broken so that the remaining one would become even more expensive.
A special part of the exhibition consists of items made from shells and mother-of-pearl from the funds of the State Historical Museum and musical instruments decorated with mother-of-pearl from the collection of the Museum of Musical Culture named after M.I. Glinka.
The exhibition is supplemented with drawings and photographs. Watercolors by Tatyana Dmitrievna Kovrigina and graphics from the collection of V.G. Belikov will be helped to see the mysterious and diverse world shellfish through the eyes of an artist.
A computer quiz and exciting games have been prepared for visitors to the exhibition: “Photo Studio”, “Dress up the Xenophore”, “Dangerous Journey”.
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