OCTOPUS
He lives at the very bottom,
At a terrible depth -
Many-armed,
Many-legged,
Nogoruky,
Footed.
Walks in the sea without boots
Octopus Squid Octopus!
(G. Kruzhkov)
Octopuses do not have a solid skeleton. Its soft body has no bones and can bend freely in different directions. The octopus was named so because eight limbs extend from its short body. There are two rows of large suction cups on them, with which the octopus can hold prey or attach to stones at the bottom.
Octopuses live at the bottom, hiding in crevices between stones or in underwater caves. They have the ability to very quickly change color and become the same color as the ground.
The only solid part of the octopus' body is the horny jaws, similar to the beak. Octopuses are real predators. At night, they get out of their hiding places and go hunting. Octopuses can not only swim, but also walk along the bottom by rearranging the tentacles. The usual prey of octopuses are shrimps, lobsters, crabs and fish, which they paralyze with poison from the salivary glands. With their beak, they can break even the sturdy shells of crabs and crayfish or the shells of molluscs. The octopuses take their prey to a shelter, where they slowly eat it. Among the octopuses there are very poisonous ones, the bite of which can be fatal even to humans.
Often, octopuses build shelters from stones or shells, wielding tentacles like hands. Octopuses guard their home and can easily find it, even if they are far away. For a long time, people were afraid of octopuses (octopuses - as they called them), composing terrible legends about them. The ancient Roman scientist Pliny the Elder talked about a giant octopus - a polypus, which stole fishing catches. Every night the octopus would go ashore and eat the fish in the baskets. The dogs, smelling the octopus, raised their barks. The fishermen who came running saw how the octopus defends itself from the dogs with huge tentacles. The fishermen barely coped with the octopus. When the giant was measured, it turned out that its tentacles reached a length of 10 meters, and its weight was about 300 kilograms.
MYSTERY
Don't you know me?
I live at the bottom of the sea
Head and eight legs -
That's all I am - ... (octopus).
STARFISH
An asterisk fell from the sky
She got into the ocean.
And now there all year round
Slowly crawling along the bottom.
(V. Moroz)
The starfish is a predator that lives on the ocean floor. Usually these animals are in the shape of an asterisk with five rays. Brightly colored starfish slowly crawl along the bottom or burrow into silt. They feed on molluscs, sea cucumbers, ophiuras and sea urchins. The mouth of the starfish is located on the underside of the body, therefore, in order to eat the prey, the starfish crawls onto it from above.
Starfish have an amazing ability to open the shells of oyster or mussel shells with their strong rays. Some stars don't even need to fully open their shells. They turn their stomachs inside out through their mouths and push it into the opening of the shell. The shellfish is digested right in the shell. After digesting its prey, the star pulls its stomach back in.
In case of danger, starfish, like lizards, can discard part of their body. But from the discarded tail, a new lizard will not grow. In a starfish, on the contrary, a new animal grows out of any part of the body. Scientists conducted experiments - cut the starfish into several parts. After a while, each part turned into a starfish. 
Starfish are relatives of sea urchins. The starfish Asterias even has a calcareous skeleton, and small needles stick out from under the skin. Another species of sea stars, the acancastera, are similar to sea urchins - their rays and backs are covered with long and poisonous spines. Acankasters wreak havoc on coral colonies by eating them.
Some starfish feed on their relatives. For example, crossasters. These huge starfish have 12 beams and grow to nearly half a meter in diameter. They are able to move quickly along the bottom and catch up with slower starfish. The crossasters themselves can feel safe because they have poisonous bodies.
SEA URCHIN
Like a cactus on the window
The sea hedgehog grows at the bottom.
The flounder swam,
I poured him some water.
(Yu Parfenov)
It turns out that hedgehogs live not only on land. There are also sea urchins. They are not relatives of land urchins, but belong to the class of invertebrates such as echinoderms.
Outside, the body of the sea urchin is covered with a shell, from which numerous needles stick out. The needles are very thin and sharp, with barbs at their ends. If such a needle sticks into human skin, it is very difficult to remove it. Sea urchins are poisonous, and, if pricked, a person will feel a burning pain.
With the help of needles, sea urchins not only protect themselves from enemies, but also move, as on stilts, along the seabed. The spear-like sea urchin moves with great speed, one might even say that he does not walk, but runs. 
Small fish use the needles of sea urchins for protection. They make a safe shelter between the needles. In gratitude for the fact that the hedgehog protects them, the fish clean his shell. These fish acquire the same color as the color of their "owner" - the sea urchin. At night, the fish briefly leave their shelter, and in case of danger they hide again between the needles.
Despite their fearsome appearance, sea urchins are often defenseless. Their main enemy is starfish. They can stick the stomach between the needles and digest the hedgehog from the outside.
The large snails that live in the Mediterranean have invented an unusual way of hunting sea urchins. They spit on their victim! The saliva of these snails contains hydrochloric acid, which paralyzes the hedgehog and eats away at its shell.
Some predatory fish release a strong stream of water from the mouth of the hedgehog. The sea urchin rolls over with its unprotected belly up and becomes an easy prey.
MYSTERY
Looks like a spiky ball
Lives deep at the bottom.
(Sea urchin)
JELLYFISH
Transparent jellyfish
Sails quietly.
You will touch the jellyfish -
How electric it will burn!
(N. Migunova)
Jellyfish are close relatives of anemones and corals. Unlike these animals, they do not spend their entire life attached to rocks, but swim freely in the sea.
Jellyfish have a translucent umbrella-shaped or bell-shaped body that looks like a jelly. These animals swim, rhythmically cutting the umbrella and pushing the water out from under it. They capture prey with the help of tentacles.
On the tentacles of jellyfish are stinging cells that can burn the enemy or even paralyze him. The poison contained in the stinging cells of the small cross jellyfish can cause fatal burns in humans. 
Another jellyfish, the sea wasp, is also dangerous to humans. It looks like an inverted deep bowl, from which twenty tentacles 10 meters long extend downward. They contain a large amount of poison.
Jellyfish feed on plankton, small crustaceans and fish.
Jellyfish come in different sizes, from a few millimeters to several meters. The largest, polar jellyfish, lives in the northern seas. Its tentacles are 30 meters long and two meters in diameter.
Jellyfish about the sea
Composes poems
But only about this
Nobody will know
She has no hands
To hold the pen
Not her mouth
To read aloud.
Medusa composes for herself,
Her silent muse is sad.
(I. Zhukov)
Jellyfish live not only on the surface of the ocean, but also in the depths of the sea. Deep sea jellyfish are capable of glowing in the dark. Small crustaceans float to the light of this living flashlight, right into the tentacles of the insidious jellyfish.
Other jellyfish also glow. The umbrella and tentacles of the pelagia jellyfish glow with a yellow-orange light. If many equioria jellyfish, living off the Pacific coast of America, rise to the surface, it seems that the entire sea is ablaze with red fire.
Slide 2
Sea hedgehog flat
The flat sea hedgehog (Echinarachnius parma) lives in soft ground where it can move in all directions. This brownish or lilac hedgehog, covered with greenish needles, has a low shell with a rather thin edge, the diameter of which reaches 10 cm. With the help of needles, it digs soil onto itself and in 10-15 minutes can disappear from sight. These hedgehogs are found at a depth of 1625 m and in places form large clusters. Representatives of this species are found in the northern and northwestern part of the Atlantic Ocean, then in the southern part of the Chukchi Sea and in the northern regions of the Pacific Ocean along the Asian coast to the south to Posiet Bay and the coast of Japan, and along the American coast to Puget Sound, including the Aleutian Islands ... Interestingly, young hedgehogs Echinarachnius parma pick black heavy grains of iron oxides from the sand and fill the diverticula (outgrowths) of the intestine with them. By doing this, they make their bodies heavier, since the density of such grains is 2.5 times higher than the density of the hedgehogs themselves. In this way, they resist washing them out of the ground. Adult hedgehogs do not accumulate heavy grains.
Slide 3
Strongylocentrus purple
Strongylocentrotus purpuratus (Strongylocentrotus purpuratus), according to Irwin, makes a large number of holes in the steel piles of port facilities on the Pacific coast of California. This medium-sized hedgehog is covered with numerous strong, long, purple-colored needles, which it rotates to drill depressions for itself. Obviously, his teeth help him in this work.
Slide 4
Hedgehog sea red-green
Red-green sea hedgehog (Sphaerechinus granularis) This species, distributed mainly in the littoral, is very beautiful. Its large, up to 13 cm in diameter, the shell has a purple color, with lighter areas on ambulacra and a greenish apical field. The shell has purple or purple needles with white tips. A hedgehog often climbs into crevices between rocks, but he never makes holes himself. Like many shallow-water animals, it often covers itself with pieces of seaweed, shells, or other objects. Usually he slowly crawls among the thickets of algae, feeding on them. Sometimes it collects detritus with small organisms in it. Its poisonous globiferous pedicellaria are a defensive device against the attack of the main enemies - sea stars. The hedgehog manages to escape if only one star attacks, but even poisonous pedicellaria cannot save it when several predators attack at the same time.
Slide 5
Trypneus
Tripneus (Tripneustes ventricosus) Martinique fishermen catch it on the coral reefs that border a large lagoon in the Atlantic Ocean. It is obtained either by divers or from rafts using a bamboo stick split at the end. The collected hedgehogs on the shore are opened, the eggs are taken out of the shell and boiled in a cauldron over low heat until it looks like a thick mass of beeswax color, after which it is again laid in the peeled hedgehog shell. Hedgehog shells with boiled caviar are sold by the hawkers by the piece. Every year, the Creole population consumes such a large number of hedgehogs that in some places on the island their shells form whole mountains.
Slide 6
Coastal hedgehog
Coastal hedgehog (Psammechinus miliaris) It can be found along the European coast of the Atlantic Ocean from Norway to Morocco. It is fairly common in oyster banks and surf areas. He is not afraid of strong waves, since with the help of coarse short needles he makes a depression in the ground, where he hides. The diameter of its shell is no more than 50 mm, its color is greenish, the needles are green with a purple tip. Eating all kinds of animal food (hydroids, sessile polychaetes, young oysters, etc.), like starfish, it harms oyster farms. This hedgehog is so omnivorous that in the aquarium it ate ascidians, dead fish, caviar, raw meat, crayfish, dead crabs, soft parts of molluscs, bryozoans, worms, hydroids, sponges, various algae, including calcareous ones. There are cases when this hedgehog lived in an aquarium for three years. When feeding in captivity, food is placed directly on the animal's shell, then he quickly begins to move it into his mouth with the help of legs and needles.
Slide 7
Sea rock hedgehog
The rock-cut hedgehog (Paracentrotus lividus), distributed from the shores of Great Britain to Africa, including the Mediterranean, is the most famous rock driller. It often forms huge accumulations on sloping rocky surfaces and in thickets of sea grass. It can be found from the littoral to a depth of 30 m. It is curious that the Mediterranean race of these hedgehogs somewhat differs in behavior from the behavior of the Atlantic race. So, individuals living in the Atlantic Ocean settle in the depressions of the rocks, made by them with the help of needles and teeth. On the contrary, in the Mediterranean Sea, they never drill rocks, but settle on slightly sloping surfaces and cover themselves with pieces of shells, sea grass and other objects. The drilling of shelters is obviously associated with the great destructive power of the ocean surf. Sometimes sea urchins find themselves walled up in shelters, since the diameter of the entrance to the burrow becomes less than the diameter of the hedgehog's body. Fleeing from the waves, the little hedgehog makes a refuge in the rock and stays there for a long time. His body grows, he expands a depression around him, but the entrance to it remains the same, and after a while the hedgehog becomes a prisoner of his house, feeding only on what the waves bring him into the hole. These hedgehogs are herbivorous, they eat various algae and sea grass. Their shell reaches a diameter of 7 cm. Its color varies from dark purple to greenish brown. According to some observations, males and females differ in color: males are darker, females are brighter. Sexual dimorphism is also manifested in the outline of the shell, which is flatter in females. Sex products are washed into the water in small portions during the summer. For many animals, this hedgehog is dangerous. Its pedcellaria are poisonous. An extract from 30 pedicellaria quickly killed a crab 4-5 cm long. However, other echinoderms, as well as humans, turned out to be immune to this poison. The caviar of the rock sea urchin is eaten. Its main fishery is in the Mediterranean Sea.
Slide 8
Sea hedgehog edible
Edible sea hedgehog (Echinus esculentus) harvested off the coast of Portugal, in some areas of Great Britain, in the North Sea. It is distributed from the Barents Sea to the shores of Spain and Portugal, it prefers to settle in coastal waters from the littoral to a depth of 40 m, less often up to 100 m, but there is a known case of its finding at a depth of 1200 m. The appearance of this hedgehog is very beautiful. It has a large, up to 16 cm in diameter, spherical reddish shell, covered with short, thin, reddish needles with purple tips and a large number of pedicellaria, with the help of which the animal keeps the shell clean and also gets its own food. This hedgehog is omnivorous. Its intestines are always densely packed with various algae, especially seaweed, as well as the remains of various small animals: barnacles, hydroid polyps, bryozoans and even the remains of other sea urchins. This makes it easy to keep in an aquarium. In a calm state, he can sit for a long time at the bottom of the aquarium, stretching up a whole forest of ambulacral legs. With the help of legs, needles and pedicellaria, it delivers food to the mouth. It is curious that when moving, this hedgehog often uses the teeth of the Aristotle lantern. In this case, the teeth are immersed in the substrate, close and raise the hedgehog, then he moves forward with the help of needles. Moving on ambulacral legs, he can walk 15 cm in 1 min.
Slide 9
Heterocentrotus
Heterocentrotus (Heterocentrotus mammillatus) has very thick, coarse needles that help it dig caves in coral polypies. He does this mainly with the needles of the oral side, the ends of which are equipped with thin teeth. This mink is so small that the animal can hardly turn in it. Sometimes a growing hedgehog remains walled up in a cave and feeds only on what the sea surf brings to its shelter, so the minks of this hedgehog are literally licked.
Slide 10
Colobocentrotus
Colobocentrotus (Colobocentrotus atratus) has adapted well to life in the strong surf. Its shell is low, oval, armed with short polygonal needles. Shovel-shaped needles are located along the edge of the oral side. The flat oral surface of the shell, together with the spatulate marginal needles directed obliquely downward and numerous ambulacral legs, creates such a powerful suction disc that it is possible to detach the hedgehog from the rock only with a knife. The flattened aboral surface of the shell, armed with short polygonal needles, perfectly resists the action of waves. This hedgehog feeds on various organisms living next to it, for example, lime algae. The commensal of this hedgehog can be considered the planarian Ceratoplana colobocentroti, which hides under its shell to stay in the surf. Its cohabitants include the small crab Proechinoecus dimorphicus and one species of molluscs.
Slide 11
Sea hedgehog heart-shaped
The sea heart-shaped hedgehog (Echinocardium cordatum) lives in the temperate latitudes of the Atlantic and Pacific oceans from the littoral to a depth of 230 m. This hedgehog lives by burrowing into sandy soil, where it makes moves, strengthening their walls with mucous secretions. It burrows into the ground with the help of lateral needles to a depth of approximately 20 cm. When the hedgehog sits in the ground, a vertical passage cemented with mucus connects it to the surface. Through this passage, thanks to the movements of the needles, which cause the water cycle in the mink, fresh water enters it, containing the oxygen necessary for breathing. The crus-like front legs of the animal are strongly extended, protruding through the vertical passage (tube) outward. The sticky outgrowths of these legs rather quickly collect the required amount of food from the surface of the soil and, being drawn back into the burrow, transfer food particles to the needles on the upper lip, which are directed into the mouth. At the same time, the hind legs are stretched a few centimeters back into the posterior tube and contribute to better excrement removal. In search of food, hedgehogs slowly crawl in the ground, pushing off with paddle-like abdominal needles. In this case, the posterior tube crumbles, and the upper (breathing) tube is re-made. Hedgehogs rarely appear on the surface of the ground, as they risk being carried away by the tidal waves.
Slide 12
Hedgehog marine heart-shaped purple
The purple heart-shaped hedgehog (Spatangus purpureus) makes not very deep moves. He lives more often on a broken shell and deepens only 5 cm from the surface, does not construct an airway. This large hedgehog, reaching a length of 12 cm, has a purple carapace and lighter, sometimes even white, curved dorsal spines. It is distributed in the northern part of the Atlantic Ocean along the European coast to the Azores and the Mediterranean Sea. It occurs up to a depth of 900 m. This hedgehog reproduces in the summer months, like most of its counterparts, it lays eggs in water, where they pass the larval stage of Echinopluteus, characterized by a long posterior process.
Slide 13
Starfish (Asteroidea)
Slide 14
Acantster
Acanthaster planci or crown of thorns, a large star, 40-50 cm in diameter, is often found on the coral reefs of the Pacific and Indian oceans. It is generally accepted that all starfish are completely harmless to humans, but careless handling of the acantaster can cause serious trouble. Numerous short beams radiate from the wide flattened disc of the acantaster. However, young stars have a five-ray structure typical of most stars, and the number of rays increases only as the star grows. Acantaster is one of the few stars that have not only a large number of rays, but also numerous madrepore plates, the number of which also increases with age. In the largest stars of this type, the number of rays can reach 18-21, and madrepore plates - 16. The entire dorsal surface of the disk and rays is armed with hundreds of large and very sharp needles 2–3 cm long sitting on movable legs, the ends of which resemble the tip of a spear ... For the shape, abundance and sharpness of thorns, this star was called the "crown of thorns". The color of the crown of thorns can vary from bluish or greenish gray tones to violet-purple and crimson. Acantaster feeds on coral polyps. The stars crawl among the reefs, leaving behind them a white streak of calcareous coral skeletons with soft tissue eaten away. The changeable color of the crown of thorns disguises it well among the bright and varied colors of the coral reef, and the star is not easy to spot at first glance. The crown of thorns is notorious for the inhabitants of many tropical islands. It is impossible to pick it up without receiving sharp needle pricks causing burning pain. Pearl pickers in the Tongareva Atoll in the central Pacific often have to deal with these stars. Miner writes that if a diver accidentally steps on one of these terrible creatures, the needles pierce the foot and break off, infecting the blood with poisonous secretions. Locals believe that the one who received such a wound should immediately turn the star with the mouth side up with a stick and press his leg to its mouth. They claim that the star sticks to the leg with force and sucks out the debris of the needles and poison, after which the wounds heal quickly.
In the 60s. of our century, on many coral reefs of the islands of the western part of the Pacific Ocean, catastrophic increases in the number of acanthates were discovered, leading in a number of places to the local destruction of coral reefs. Concerns have arisen for the fate of some of the islands, as the living coral reefs that have served them as protection from ocean waves have begun to collapse after the death of the corals. I had to develop urgent measures to combat the acantaster. The most effective was the destruction of stars by injecting formalin with a syringe into the star's body by divers-scuba divers. In this way, for example, on the reef of the island of Guam, a team of scuba divers destroyed more than 2.5 thousand acantasters in 4 hours. Various hypotheses have been proposed to explain the reasons for the extraordinary increase in the number of stars. But, apparently, these outbreaks of reproduction of acantastera are similar to similar outbreaks that periodically occur in some other animals (for example, locusts, silkworms, lemmings, etc.) and then fade out (their reasons are not yet fully understood). Likewise, by now the number of acantasteurs has declined everywhere to normal levels, and coral recovery and growth has begun in the areas of coral reefs destroyed by them.
Slide 15
Anzeropod
Anzeropod (Anseropoda placenta) is distributed off the Atlantic coast of Western Europe and in the Mediterranean Sea. Anzeropod - an asterisk burrowing into the sand, about 10 cm in diameter, has an extremely flattened body, the pale pink or bluish surface of which is completely covered with bunches of very small needles. The texture of the surface and the insignificant thickness of the body of the anzeropod resembles a wafer. Its body is so thin that the upper and lower sides seem to be closely pressed against each other, without room for any internal cavities. Nevertheless, the anzeropod manages to swallow whole small crabs and hermit crabs, as well as small molluscs and echinoderms.
Slide 16
Patiria scallop
The scallop patyria (Patiria pectinifera) has the form of a regular pentagon, an exceptionally spectacularly colored small star is common in the littoral of the Sea of Japan. On the upper side of this star, bright orange spots are scattered against a background of a rich pure blue, and the oral side has a uniform fawn color.
Slide 17
Kulcita New Guinea
Culcita novaeguineae looks like a small pillow. The cult is remarkable not only for its unusual shape for the stars, but also for the fact that in its body cavity a small so-called pearl fish carapus (Crapus), also known under the older name Fieraster, is sometimes found. Carapus usually keeps close to some sea cucumbers and, in case of danger, uses their aquatic lungs as a temporary refuge. Apparently, the carapace penetrates into the cult when its usual owner is not nearby in case of danger. But the carapace can probably penetrate into the body cavity of a star only by making its way through its mouth into the stomach and then piercing its wall. It is not yet known whether the fish is able to escape to freedom from such an unusual refuge again.
Slide 18
Linchia
Linckia (Linckia laevigata) is quite common in the tropical shallow waters of the Pacific and Indian oceans. It is a bright blue star with five long, nearly cylindrical beams. For this star and for other species of the genus Linckia, a special type of asexual reproduction is very characteristic, which is not found in other stars. Links have the ability to periodically autotomize, that is, to spontaneously break off their rays. This process begins with the separation of skeletal plates from each other, most often at a certain distance from the disc. Then the detached part of the hand begins to crawl away from the mother, while still being connected to her by soft tissues and skin. Over the course of three to four hours, these tissues stretch more and more (sometimes up to 5 cm) and finally break, after which the detached hand begins an independent life. After some time, a new star begins to develop at the site of the break at such a hand, as a result of which the so-called comet form of a star with a group of tiny rays at the end of a single large hand is first formed. In the future, new rays grow and the star takes on a normal appearance. At the mother's star, a new one grows in place of the severed hand. In places where Linkia are numerous, both comet stars and stars regenerating one or more arms are often found. If the end of the autotomized hand is cut off additionally, then sometimes regeneration can begin from both ends and thus two young asterisks can form, connected by a thick section of the mother's hand.
Slide 19
Asterias
Asterias (Asterias forbesi) has been studied in the most detailed and comprehensive way, and therefore, on the description of this sea star, the life of the most typical sea stars can be traced. Asterias is a small five-pointed star, the distance between the ends of opposite rays usually does not exceed 20 cm, but stars with a diameter of about 10 cm are most often found. The color of A. forbesi varies from orange-red to greenish-black tones. A. forbesi feeds mainly on oysters and mussels, but also eats other molluscs, small crustaceans, worms and dead fish, and on occasion attacks the living, especially the sick or entangled in the net. With a lack of food, the asterias also noted cases of cannibalism - larger stars eat smaller individuals of their species. Asterias causes great harm to oyster farms. Therefore, the American scientists P. Galtsov and V. Luzanov specially devoted a number of years to the study of the biology of this star and the development of measures to combat it. According to these authors, the voraciousness of the asterias is so great that one medium-sized star can destroy several one-year-old oysters daily. At the same time, A. forbesi is very fertile and, under favorable conditions, multiply in huge numbers, literally devastating and ruining oysters. In the 20s. of the last century, starfish annually destroyed about 500 thousand bushels of oysters off the Atlantic coast of the United States (a bushel is a measure of volume, about 35 liters), which caused losses in the amount of about half a million dollars a year. Reproduction of asterias usually occurs several times during the summer. In this case, even a slight increase in water temperature can serve as an incentive for the start of reproduction. Stars of both sexes raise the body above the bottom at the ends of the beams and sweep the reproductive products into the water through paired holes at the base of each beam. The remnants of the gonads after the sweeping of the gonads degenerate, in the fall the formation of new gonads begins, which grow rapidly and by the beginning of next summer are again filled with mature eggs and spermatozoa. After three to four weeks of free existence in the water, the larvae settle and turn into tiny stars with a diameter of about 1 mm, which soon begin to feed on juveniles of mollusks and other animals that have recently settled to the bottom. Young stars also eat each other, as a result of which their number in the first month after settling is greatly reduced. During their life in plankton, the larvae do not move far from the place where eggs are spawned, and the most massive settling of juveniles usually occurs precisely where the adult stars are especially numerous.
Slide 21
Astromethis
Astrometis (Astrometis sertulifera) prefers to settle in places protected from bright light. This small five-pointed star lives in the shallow waters of the Pacific coast of North America, from California to Vancouver Island. purple bases. The underside of the star is straw-yellow, and the ambulacral legs are bright canary-colored. The bases of the dorsal spines are surrounded by rosettes of numerous small pedicellaria, and larger single pedicellaria are scattered over the surface of the body. According to Jennings, the main purpose of pedicellaria is to protect the delicate cutaneous gills located between the spines. When the surface of the skin is irritated by small crustaceans or other animals that have crawled onto a star, papules contract and retrace, and pedicellaria begin to open and close their tweezers until they manage to grab an animal that has caused irritation or a foreign particle that has got on the skin. Captured small crustaceans pedicellaria can keep without releasing for more than two days. All grasped by the cedicellaria hold so firmly that it is possible, for example, to raise a star out of the water by the pedicellaria, grasping the hairs on the skin of the hand.
Slide 22
Pizaster
Pisaster brevispinus made very interesting observations over this large predatory five-pointed star. Crawling along the bottom, this star unmistakably stops above the place where one of the burrowing mollusks from the genera Saxidomus and Protothaca is located. After that, the star begins to tear apart the soil, throwing sand and small pebbles up to 2 cm in size with its legs. This work lasts two or three days, and digging takes place only at night, and during the day the star lies motionless at the site of its excavations. In the end, the star digs out a hole equal in diameter to the size of its body (up to 70 cm) and a depth of about 10 cm shells. Then she lifts, leaning on the ends of the rays, the central part of her body and pulls the mollusk out, after which she deals with it in the usual way for asterids, opening the shell and sticking her stomach into its cavity. Sometimes stars of the same species from different habitats differ significantly from each other in biology, in particular, in the nature of their feeding and the behavior associated with it. So, the memasters living off the coast of California eat mainly flat hedgehogs of the genus Dendraster, and to the north - in Puget Sound, crawl among the settlements of these hedgehogs, not paying attention to them, and feed on mollusks, digging them up, as described above. Accordingly, the reaction of Dendraster in both regions to the proximity of this star is also different. Californian hedgehogs immediately begin to bury themselves in the sand when a dangerous star crawls near them, and hedgehogs from Puget Sound do not react to stars even at a distance of several centimeters and begin to bury themselves, only disturbed by a star accidentally creeping on them.
Protective reactions to touch or proximity of predatory stars are also developed in many other animals. For the most part, this is a reaction of flight from the star. X. Feder very colorfully describes such a reaction in the large gastropod mollusk abalone (Haliotis). Upon contact with the pizazster, the mollusk lifts the shell on its thick leg and begins to rapidly rotate it 180 ° in one direction or the other. Having freed itself with such shaking movements from the legs of the star stuck to the shell, the mollusk turns and crawls away from the predator with a "gallop-like gait". At the same time, his leg sharply contracts and stretches, making movements more characteristic of a leech or a caterpillar of a moth than a large snail. Saucer gastropods (Acmaea) react in the same way to predatory stars.
Slide 23
Pycnopodia
Pycnopodia (Rusnopodia helianthoides) living on rocky bottom areas covered with thickets of brown algae off the northeastern Pacific coast from California to the Aleutian Islands is a real giant among sea stars. The dorsal skeleton of this star is practically absent, and its numerous rays are distinguished by extreme flexibility and mobility. The largest stars reach 80 cm in diameter and 4.5 kg in mass. When such a star crawls, spreading two dozen of its rays along the bottom, its body occupies an area of about 0.5 m. The red-brown surface of the body is covered with numerous groups of gray-violet branched papules, between which clusters of pedicellaria are scattered. Well-known expert on starfish W. Fisher describes the behavior of pycnopodia as follows: “It feeds mainly on sea urchins, hermit crabs and other animals that it manages to catch, attacks large sea cucumbers and eats dead or weakened fish. She catches the latter with her rays, almost as mobile as the arms of an octopus. Excited by the proximity of food, she moves very quickly and is more active than any other stars I have seen. When this star crawls quickly with thousands of its wriggling legs, it makes an impressive impression, and its numerous pom-poms of tenacious pedicellaria and a wide, flexible body make it a formidable weapon of destruction. In the fight against resisting fish or crab, it can activate more than 15 thousand feet with suction cups. The pycnopodia completely swallows the large sea urchins Strongylocentrotus, and after a while throws out a clean hedgehog shell devoid of needles. After a battle with the sea urchin, the legs of the pycnopodia are abundantly planted with hedgehog pedicellaria, which stand out brightly with their purple color against the light yellow background of the legs. Sometimes pycnopodia even fall on the fishing rods of fishermen, seizing the bait from fish or shellfish meat. " Pycnopodia are interesting not only for their large size and predatory feeding method. This star has developed for the second time some features of bilateral symmetry in addition to those inherited by the stars from their ancestors. The pycnopodia begins its life at the bottom in the form of a small five-pointed asterisk, from which the sixth ray soon grows, occupying, as a rule, a strictly defined position in relation to the interradius with the madrepore plate. A further increase in the number of rays occurs through the formation of more and more pairs of symmetrical rays on both sides of the sixth ray, the number of which may eventually reach 24. Bilateral symmetry is also manifested in the physiology of the star. The pycnopodia usually moves forward the same specific rays, and these same rays are used primarily for turning over to its normal position when placed with the mouth side up.
Slide 24
Evasterias
Evasterias troschelii This star has been well studied the way in which sea stars manage to discover and eat bivalve molluscs. Evasterias inhabits shallow waters off the Pacific coast of North America. In bivalve mollusks of the genus Protothaca, the locking muscle was cut and then their valves were pulled together with a rubber band, which is a kind of dynamometer. Observing how the stars eat such mollusks, it was possible to establish that a star with rays 20 cm long can stretch the valves with a force of more than 5 kg. In this case, the star only needs to slightly open the flaps. Even in a slot a few tenths of a millimeter wide, she is able to push her stomach stretching like rubber. In mussels, at the exit from the shell of thin filaments of byssus, with which the mollusk is attached to the substrate, there is an unclosed gap about 0.1 mm wide. To push the stomach inside the shell, the star is enough and such a negligible hole, and in order to feast on the mussel, she does not even have to spend efforts on opening the shell. To find out how long a star can stretch its stomach turned outward, the stars were offered mussels placed inside plastic tubes at different distances from their end. It turned out that the star is capable of destroying a mussel located 10 cm from the hole, stretching its stomach to a distance equal to half the length of the ray, and in some cases to its entire length. It is still not completely clear whether the Evasterias secretes any substances poisonous to molluscs that cause relaxation of the locking muscle. For a number of species, it has been proven that the star opens the shell only through mechanical force. But it is possible that some stars use both methods at the same time.
Slide 25
Blood star
The blood star (Henricia sanguinolenta), named for its rich red color, is common in the Arctic and North Atlantic Ocean. This star feeds exclusively on various types of sea sponges. At the same time, she can recognize, through chemoreception, her preferred types of sponges, even being at a considerable distance from them.
View all slides
10. SEA URCHINS, STARS, LILIES AND GOLOTURI
TO What amazing animals live at the bottom of the sea! They have no right or left side. They can crawl in all directions and in each direction they move forward. They are called echinoderms. There are thousands of calcareous plates in their bodies. This external skeleton protects animals that are slow in their movement. Many, like sea urchins, are still protected by a mass of needles sticking out in all directions. The sea urchin calmly crawls along the bottom, not being afraid of gluttonous predators. It has the shape of a slightly flattened ball, on which there are five rows of thin transparent suction cup legs. With the help of these legs, the sea urchin slowly crawls along the bottom with its mouth downward.
The starfish is either a pentagon or a five-pointed star. There are also multibeam stars. Five rows of the same transparent legs-suction cups, like those of a hedgehog, protrude along the lower surface of the star's rays. But the hedgehog is a peaceful animal, and the star is a predator. In pursuit of prey, she must move quickly. Her moving rays come to her aid. By quickly bending and unbending its rays, the star moves in search of food. She often attacks animals larger than her, which she cannot swallow. Then the star throws out the stomach from itself, envelops the caught prey with it, digests, and then pulls the stomach into the body. The sea star also has enemies. A predatory fish will catch it, bite off one or more rays. Another animal would have died from such an operation. But the star not only survives, it quickly grows new rays to replace the ones that were torn off. This ability to repair damaged body parts perfectly protects the starfish from death.
Swaying on a thin leg, similar to a flower, the sea lily lives on the bottom of the sea. This is not a plant, but an animal, but only it grows to the ground. At great depths, where waves do not reach, there is no need for strong supports. You can also live on a thin leg. Throwing out its arms, which serve it not for grasping passing prey, but for creating a stream of water, driving small organisms floating in the water into its mouth, the sea lily feels great at the bottom of the sea.
Echinoderms also include sack-shaped holothurians or, as they are also called for their body shape, sea cucumbers. By the presence of small calcareous bodies in the skin, along five rows of legs, we see that sea cucumbers are relatives of sea urchins, stars and lilies. They crawl over rocks, dig in sand and silt. There are always many remains of dead animals and plants in the silt. Holothurians feed on them. Among the sea cucumbers there is a very commercially valuable breed called trepang. Trepang lives at the bottom of our Far Eastern seas. In China, trepang is prized as a delicious dish. Large consignments of these sea cucumbers in dried form are sent to China and other countries of the Far East.
Echinoderms are very ancient animals. In the deepest strata of the earth, you can find prints of sea urchins, lilies and stars. Among them there are also such forms that are not among those living now. But there are also those who live at the present time.
Echinoderms are real marine animals, they are absent not only in fresh water, but even in slightly salty seas.
TO There are no such fish in the sea! In some, the body, like a torpedo, is elongated in length. Others are flat and lie on the bottom of the sea. There are fish that are long, like snakes, and round, like balls. All this variety of forms is associated with the way of life of fish. Once upon a time, fish were not what they are now. The living conditions in the seas changed, and the appearance and organs of the body of fish also changed. They became more diverse and more and more different breeds appeared. Fish began to live not only in warm seas, but also in cold ones.
Some fish feed where they live. Others hunt fleeing prey. Still others make huge journeys in search of food. Fry often live in the surface layer of water, and adults at great depths. Herring spend their whole life in the water column, and lay their eggs on the bottom. Most fish live their entire life in the sea. Some come in to spawn in the rivers. It is difficult to describe all the diversity of the fish population of the sea.
Fish are of great commercial importance. Fishing is the richest branch of the national economy. Thousands of ships come from the sea, laden with a rich catch. Hundreds of factories on the shore freeze, salt, smoke or make canned fish. Fish meat is very tasty and nutritious, fish oil saves children from rickets - it contains a lot of vitamins. Fish meal is made from heads and bones - good pet food. Even fish skin finds use.
We hear many stories about sharks. They are excellent swimmers, voracious predators. Their mere appearance causes a commotion in the fish school. The shark's body, stretched out in length, is like a torpedo. It is wider in the head than in the tail and easily cuts the water. The strong tail serves as the main organ of movement. The shark can reach speeds of up to 20 kilometers per hour. Usually sharks are 2-4 meters in size. Sharks are predatory. You have to be very nimble or inconspicuous (disguised) to escape the sharp teeth of the voracious fish. It happens that sharks attack humans. There are real giants among sharks, reaching 30 meters in length, but these sharks are peaceful inhabitants of the sea. They feed on small crustaceans that grow in huge numbers in the seas. Such a shark will swim in a huge school of crustaceans and filter the water. All this little thing remains in her mouth. Each crustacean weighs a milligram (1/1000 gram), and millions and billions of these crustaceans are quite capable of feeding a giant shark.
Other fish predators use trickery to hunt for food. A fish called "sea devil" lies quietly at the bottom among the stones. The antennae move on his head. Any fish will pounce on an imaginary worm and end up in the huge mouth of the sea devil. And you don't need to swim, and the food goes into your mouth by itself!
To disguise, to become invisible, is very beneficial in the ongoing war that is being waged in the depths of the sea. Among the stones, completely pressed to the bottom, lies a flat fish flounder. The upper part of her body is painted to match the color of the surrounding soil. You can't see her at all. Moreover, the flounder will swim from the sandy ground to the rocky one, and its color and the location of spots on the body will immediately change. On sandy soil, the pattern is small, on rocky it will become spotty. The flounder skin contains special colored cells that can rise to the surface or sink deep into the skin. With the help of these cells, the pattern and color of the flounder's skin quickly change when it gets from one soil to another. This is how a defenseless flounder escapes from its enemies. A shark swam, darted in different directions, looked at the bottom with a keen eye and found nothing. Everything was hidden, disguised, as if there was no stormy life here a minute ago.
Among the twigs of corals, motley little fish swim, somewhat resembling butterflies in their color and body shape. Variegated, brightly colored, they are striking in the aquarium, but become completely invisible among a variety of corals. Military camouflages could learn a lot from coral reef fish. What military science came to was developed in these fish long ago in the struggle for existence.
What is this strange phenomenon? Like a flock of sparrows flew off the wave and scattered in different directions. They flew several tens of meters, barely touched the wave and quickly flew further. Some of them even flew onto the deck of the ship. These are wonderful silvery fish, whose pectoral fins have turned into wings. How many progenitors of these flying fish perished from generation to generation, until their fins developed into wings, allowing them to fly away from the pursuit for a hundred meters. This is beneficial to them also because the enemy loses the direction of the pursuit. But the wing of a fish is not the wing of a bird, but of an airplane. A flying fish does not flap its wings. Fleeing from the pursuer, the fish quickly swims, working with its tail, to the surface of the sea. The wing-fins are pressed to the sides of the body, the whole body is directed upwards. Finally, the fish reached the surface. Like a real seaplane, it quickly takes off, then spreads its wings to the oncoming air flow and takes off. It flies in the air like a glider. "Motor" - her tail, it worked in the water. If you need to fly further, the fish will touch the waves, pick up speed again and take off again.
There are more than a hundred nature reserves in Russia, but only one of them, the Far East, is a marine one, it was created in 1978 to preserve the gene pool of marine and coastal communities, 98% of its territory is water area.
In the Gulf of Peter the Great, where the Far Eastern Marine Reserve is located, cold (boreal) waters mix with the warm waters of the subtropics, this creates favorable conditions for the emergence of a rich and varied marine flora and fauna. The water area is inhabited by more than five thousand inhabitants, plants and marine aquatic organisms.
The density of the marine population is maximum at a depth of 5-10 m. Thickets are often found here. kelp, sargassum and other algae and sea grasses, where numerous invertebrates live.
At the bottom live small algal crabs, hermit crabs, starfish, spherical sea urchins come across.
On the stones - sea acorns, sea anemones, echinoderms: sea urchins and starfish. They also settled here Far Eastern trepangs, and in sandy crevices - anemones.
According to preliminary estimates of scientists, there are over two thousand species of invertebrates in the reserve, and among them there are many unique ancient creatures, this fully applies to sea urchins and trepangs.
Sea urchin
The class of sea urchins consists of 7 orders, including 950 different species.
They live only in highly salted water, therefore, sea urchins are not found in the relatively slightly salted Caspian, Black and Baltic seas.
The sizes of hedgehogs are very diverse: from the size of a tennis ball to 30 cm in diameter. The body of the sea urchin is covered with a dense calcareous shell and needles, with the help of which it moves, and also defends itself from predatory inhabitants of the sea depths.
The needles in most species contain venom that causes severe pain and even temporary paralysis of the limbs.
Despite the protective shell and sharp thorns, the sea urchin is eaten by predatory fish, birds and mammals. They have learned how to get to the tasty contents: birds throw the caught hedgehog onto stones, breaking its shell and thorns, sea crayfish prick the shells of hedgehogs with their claws, and starfish are able to reach the soft contents of the hedgehog between the needles with their rays and eat it without "undressing".
Most of the inhabitants of Central Russia, living far from the habitats of sea urchins, first get to know them "from the bad side", on foreign beaches, accidentally stepping on sharp needles while swimming.
However, these ancient creatures (they appeared on Earth over 500 million years ago) can also be of great benefit. In particular, the healing properties of sea urchin caviar.
Foreign biologists are also engaged in large-scale studies of sea urchins. British scientists have discovered in sea urchins a peptide similar to the human hormone calcitonin, which is responsible for bone strength. With age, hedgehogs do not lose the ability to reproduce, and they practically do not show signs of aging. Scientists have found that sea urchins have the most complex immune system among all animals studied to date, which may explain the existence of long-lived hedgehogs. A 200-year-old "aksakal" was discovered off the coast of California.
Specialists from the Pacific Fisheries Research Center (TINRO) are successfully researching the beneficial properties of marine life and developing health products based on them. Sea urchins did not go unnoticed. Studies of sea urchins of the strongylocentrotus family common in the Sea of Japan have shown that “due to the content of unique biologically active substances (phospholipids, polyunsaturated fatty acids Omega 3 and Omega 6, carotenoids, vitamins, macro- and microelements, essential amino acids, nucleic acids), sea urchin caviar is widely is known as a product for enhancing the protective properties of the body, has a powerful antioxidant effect, and prevents the natural aging of the body. "
Scientists are studying in detail the unique properties of sea urchins, hoping to reveal the secret of eternal youth for people in the future.
But even now, many useful products from the sea urchin have already been created, which allow, if not stop, then significantly delay old age.
Trepang
The Far Eastern sea cucumber Apostichopus japonicus is another hydrobiont actively used for human health, for example, in Southeast Asia, it is primarily appreciated for its general strengthening properties. References to the miraculous properties of trepang can be found in treatises of the 16th century.
The Far Eastern trepang is the only absolutely sterile marine inhabitant - there is not a single microbe or virus either in it or nearby. If you cut off a piece of sea cucumber and throw it into water, then in a few months this piece will turn into a full-fledged adult - this is the unique ability of the sea cucumber to regenerate.
Trepang contains triterpene glycosides, lipids, hexosamines, methionine, organically bound iodine, various trace elements, vitamins, prostaglandins. Triterpene glycosides have a strong anti-fungal effect. Far Eastern trepang extracts have a high content of polyunsaturated fatty acids and phospholipids, which helps to cleanse blood vessels. including supplying the genitals with blood for.
