The shellfish are the most interesting. Cephalopods: description, structure, interesting facts

The diversity of mollusk species living on our planet is truly enormous. They exist both in water and on land, and look completely different when they are similar friend no more similar to each other than one mammal is similar to another. Because of this, many mollusks are still very poorly studied, and scientists still have a lot of work to do to fill the gaps in our knowledge about these creatures.

1. It is still unknown how many species there are on Earth. Different scientists give figures from 100 to 200 thousand. Of these, about 3,000 live in Russia.
2. Among all classes of mollusks, the majority are gastropods, such as snails - as much as 80%. Another 19% comes from bivalves - oysters, mussels and the like. And the remaining 1% falls on all other classes at once.
3. The world's largest bivalve mollusk is the giant tridacna. It can weigh up to 250 kg, and lives at depths of up to 100 meters.
4. The weight of the largest mollusk ever caught reached 360 kg. It was caught in the 50s of the 20th century off the coast of Japan (see).
5. Most of all mollusks living in sea and ocean waters feed on plankton.
6. The largest mollusc species in the world is the giant squid. Some individuals reach 18 meters in length. It is also one of the rarest; it was first photographed only in 2007.
7. The age of all mollusks with a shell can be calculated by the number of rings on it, just as the age of most trees is determined by the growth rings. One exception to this rule is the baobab, which does not have growth rings (see).
8. The oldest animal on Earth is still considered to be a mollusk caught off the coast of Iceland. Its age, according to scientists, exceeded 400 years.
9. Octopuses have unique rectangular pupils.
10. The predatory mollusk rapana came into the Black Sea from the Sea of ​​Japan on the bottoms of ships in the 40s of the 20th century, and since then it has multiplied greatly, practically displacing mussels, oysters and other competitors, because in the Black Sea there are no starfish that feed on rapana (see . ).
11. The smartest mollusks in the world are octopuses. They are trainable and understand commands.
12. Extinct ammonite mollusks reached 2 meters in length. Their shells are still sometimes found in the sand and on the seabed.
13. Blood in shellfish blue color, and not red, since the function that iron performs in our blood is taken over by copper in their blood (see).
14. Oysters are bivalve mollusks that can change sex if necessary.
15. Almost all nudibranchs, of which there are about 3,000 species in the world, are poisonous to one degree or another.
16. In one season, the common oyster produces more eggs than any other shellfish - up to a million, or even more. But only a few of them survive.
17. Fossilized remains of marine mollusks are found from time to time on the slopes of Everest, highest mountain peace. It was once part of the ocean floor.
18. In 2000, it was discovered in the coastal waters of Cuba the new kind shellfish, similar to a flower and notable for the fact that it emits pulses of light when exposed to external stimuli.
19. Cone mollusks hunt fish by literally harpooning them with their teeth. At the same time, they are poisonous, so much so that they can kill a person (see).
20. The sea slug mollusk obtains energy through photosynthesis, like plants.
21. Even 200 years ago in Europe, shellfish, oysters and mussels were considered food for the poor. They were actively eaten, there were few of them left, and they became delicacies.
22. Octopuses can mimic like chameleons, changing not only the color of their skin, but also its texture.
23. Most mollusks have a fair portion of their body made up of muscles. If humans had the same percentage of mass as muscle, we could easily lift half a ton.
24. Scallop mollusks are able to move by opening and quickly closing their valves. The ejected stream of water creates a reactive force, which helps them move.
25. In some species gastropods, snails, have more teeth than any other creature in the world - up to 25,000.
26. Some species of mollusks, such as slugs and snails, take part in the pollination of some plants.
27. Octopuses can throw a stream of ink into the water to hide from the enemy.
28. Octopus mollusks, also known as octopuses, are the only creatures that live in water and have a beak like a bird's.
29. The giant squid, the largest of the mollusks, has an eye diameter that can reach 65-70 centimeters.
30. The ringed octopus mollusk that lives off the Australian coast is very beautiful, but its bite is deadly poisonous. One serving of poison can poison 5-7 thousand people.

The largest mollusk, and indeed invertebrate in general, is the giant squid Architeuthis dux. The length of the largest currently known squid is 18.5 meters. It was caught in New Zealand in 1880. They say that the first mention of these mythical (then) sea animals dates back to 1555. Squids were called both sea snakes and octopuses, and at the same time, for a very long time they refused to believe in their existence. For the first time photographing a living Architeuthis dux in its natural environment Japanese scientists were able to find habitats in September 2007. Now in the British Museum of Natural History (Natural History Museum), a 9-meter specimen is stored in the form of a wet preparation (Based on materials from the magazine Membrana).

The largest of the bivalve mollusks is the tridactna (Tridacna gigas). Its weight can reach 333 kg, and the width of the shell is 1.4 meters. The tridactna shell is often used as a baby bath. In Notre Dame Cathedral, a tridactna shell serves as a baptismal font. There is an opinion that tridactna is dangerous for divers, since when disturbed it can trap the diver’s hand between the valves. However, in fact, it does not pose a danger to divers, unless they are too slow or reckless (stupid).

The largest gastropod gill mollusk is Syrinx aruanus, for which individuals are known with a shell 80 cm long and weighing 18 kg.

The largest land mollusk is Achatina fulica, whose leg size can reach 39 centimeters and weighs 900 grams.

Details of the movement of aquatic snails along the surface of lakes and rivers were revealed by engineer Eric Lauga from the University of California at San Diego (UCSD). The secret of the movement is the wave-like movements of the leg (the test subject was a snail of the species Sorbeoconcha physidae). Water “resists” disturbances; it “wants” to remain smooth, the researcher explained. So the waves on the snail's leg create water waves, which provide driving force. The leg deforms the free surface, thereby creating a pressure gradient and generating flows inside the thin layer of mucus that separates the snail from the water surface,” explains the experimenter. (According to Membrana magazine)

Dr. Benjamin Hochner and his colleagues at the Hebrew University of Jerusalem discovered that the octopus, which has virtually infinite degrees of freedom in its tentacles, can form a human-like "arm joint" when eating to carry food to its mouth. (By materials from Membrana magazine).

Clams are incredibly powerful. If a person had the same strength, then a fifty-kilogram person could easily rise vertically upward with a load of half a ton.

Unusual found in Cuba sea ​​clam, emitting light signals when irritated. This discovery was made by Cuban and Spanish researchers working on the island with the Macaronesia 2000 underwater fauna research project (Macaronesia 2000) (Based on materials from Oceanology.ru)

Shells of land mollusks have been found even in the Nazca Desert. It has been established that the Nazca Plateau was once covered with forests

Scientists have found that the shells of bivalve mollusks (and the epithecus of corals) bear daily traces of growth in the form of lines, by counting which the number of days and months in a year can be determined. Similar ones showed that in the Paleozoic there were more days per year than now. These data were confirmed by calculations by astronomers and geophysicists.

Mollusks from the family Conidae (cones) are very beautiful and are often found in collections. However, these mollusks are very poisonous. Being predators, cones hunt fish by harpooning them with a greatly enlarged radula tooth. Through this harpoon, the mollusk injects strong poison into the body of the victim. A number of cones are so poisonous that they can cause serious harm or even kill a person. Most often this happens when people collect shells on the shore or in shallow water.

Interesting facts about shellfish.

1. The largest clam ever caught weighed about 340 kilograms. It was caught in Okinawa, Japan in 1956.

2. The oldest clam caught by humans was estimated to be around 405 years old, possibly making it the oldest marine animal.

3. The age of mollusks can be determined by the number of rings on the shell valve. Each ring differs from the previous one due to the characteristics of the food consumed during this period, the state of the environment, temperature and the amount of oxygen in the water.

4. The main type of food of mollusks is plankton, which they filter from the water.

5. Oysters can change sex. One season a woman, the next a man.

6. An oyster can produce about a million eggs in one season. However, only a few will be able to survive and grow to adulthood.

7. Some varieties of scallops have dozens blue eyes along the edges of the shell. With their help, scallops can notice predators and escape in time.

8. Bivalves can move. Scallops, for example, rhythmically squeezing their valves and throwing out a stream of water can swim quite far from their enemies - starfish.

9. Nudibranchs number about 3000 species, beautiful and poisonous inhabitants seas, are characterized by a complete absence of shell. However appearance deceptive. Nudibranchs are very poisonous; just touching such a beauty can remove the skin from your hand. Another feature of these creatures is the presence of genital organs on the tail and head. These mollusks range in size from 6 millimeters to 31 centimeters. Nudibranchs feed on algae, anemones and even other mollusks. They owe their beautiful coloring to what they eat. Here are some photos of these beautiful and extraordinary creatures.

10. The world's largest bivalve mollusk is the giant tridacna. The diameter of its shell can reach two meters and its weight can reach 250 kilograms. This giant lives in tropical waters and can safely settle at depths of up to one hundred meters. Also widespread among aquarium enthusiasts. IN Lately Tridacna has been practically exterminated, but there remains hope that this miracle of nature will survive at depth, where it is more difficult to obtain.

11. The largest mollusk in the world (also the largest invertebrate in the world) is a giant squid called Architeuthis dux. Its length is more than 18 meters. This representative of invertebrates was caught in 1880 in New Zealand. The first mention of them dates back to 1555. At that time, squids were called octopuses, sea snakes, and people in general for a long time refused to believe in their existence. Japanese scientists were able to photograph Architeuthis dux for the first time in 2007.

12. The @ symbol, which we call “dog,” is called “happy snail” by Koreans.

13. The most beautiful, but deadliest sea wasp in Australia is the most poisonous jellyfish all over the world. Off the coast of Queensland, 66 people have died from its poison since 1880.

14. In Japanese cuisine there is a very interesting dish called “dancing squid”. A freshly killed clam is placed in a bowl of rice and watered on top. soy sauce and it is at this moment that the squid begins its dance, moving its tentacles. This effect is explained by the unusual structure of nerve fibers, which, even after their death, react to the sodium contained in the sauce, and this causes the muscles to contract.

15. Empty mollusk shells were found in the Nazca Desert, which, as we know, was previously covered with continuous forest.

16. An unusual thing was found in Cuba interesting mollusk, which emits light signals during stimulation. It was discovered by Spanish and Cuban researchers who worked on the island to study the underwater fauna of Macaronesia 2000.

17. Clam cones, belonging to the family Conidae are extremely beautiful and very often found in collections. But they are very poisonous and are predators by nature. When hunting fish, they harpoon it with a greatly enlarged tooth, through which they inject strong poison into the body of the victim. Some cones are so poisonous that they can even kill a person. This happens when people collect shells from shallow waters or shores.

18. Not only some plants can carry out photosynthesis. The sea slug Elysia chlorotica, which lives only on glucose, obtains it from the chloroplasts of the algae Vaucheria litorea. This mollusk achieves this by assimilating chloroplasts directly into the cells of its digestive tract, and after this process photosynthesis begins: the genome encodes the proteins that the chloroplasts need, and in return it receives synthesized glucose.

19. The sound of the sea in souvenir shellfish shells is the noise of your environment, which resonates with the cavities of the shell. This effect can be achieved without a mollusk shell by placing a bent palm or a mug to your ear.

20. In France and England in the first half of the 19th century, oysters were considered food for the poor who could not afford to buy meat. However, uncontrolled fishing of these mollusks led to a sharp decline in the population of these individuals, and in the second half of the 19th century they became very expensive, becoming a delicacy.

21. Starfish can feed without swallowing food. For example, when encountering a bivalve mollusk, she grabs it and turns the lower stomach outward. This, in turn, penetrates the shell, enveloping the softest parts of the mollusk, and subsequently digests them. The starfish then draws in the resulting solution.

22. An octopus, in order to hide from its enemies, can adapt to the color of the soil or water, changing the texture and color of its skin.

23. Thanks to changes in their shells, mollusks are able to maintain body temperature, preventing it from rising to the lethal threshold of +38 degrees. Moreover, this happens even when the air warms up to +42.

Mollusk – amazing creature, which amazes with its beauty, many interesting properties and unusual facts.

© Inga Korneshova especially for the site

Mollusk Arctica islandica, living in the waters of the Atlantic and North Arctic Oceans, can live about 500 years. This is one of the longest living creatures on Earth.

On an industrial scale, the cultivation of shellfish was organized in Japan in 1915. The essence this method comes down to placing a particle in the shell, around which the mollusk builds up the mineral. The method was invented by Kokichi Mikimoto, who received a patent for his invention.

The marine Elysia chlorotica assimilates chloroplasts from the algae Vaucheria litorea, which are capable of in slug cells for several months.

In gastropods with a turbo-spiral shell shape, the liver is located in the last turns of the spiral

The fish is not naturally poisonous. She collects only when she eats poisonous starfish and shellfish. If you put it on a non-toxic diet from birth, the tetrodotoxin content in the fish will be zero. However, without its toxin, the pufferfish becomes just another type of fish - quite tasty, but of no interest to gourmets. The secret of the popularity of fugu is in the acute sense of risk, for the sake of which the Japanese cook it.

For 150 years

Ecology

IN sea ​​depths sometimes you can meet incredible creatures, which 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 unique species to this list. 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 ended up in the same family of living creatures as 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 got this strange name thanks 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 Shiyo Seamount near the Tokyo hydrothermal vent. These are the only representatives of the genus that have been 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.