Description: War Thunder is a next generation military MMO game dedicated to...
Jellyfish can rightly be called one of the most mysterious inhabitants of the deep sea, causing interest and a certain fear. Who are they, where did they come from, what varieties are there in the world, what is their life cycle, are they so dangerous, as popular rumor says - I want to know about all this for sure.
Jellyfish appeared more than 650 million years ago, they can be called one of the oldest organisms on Earth.
About 95% of the body of a jellyfish is water, which is also their habitat. Most jellyfish live in salt water, although there are species that prefer fresh water. Jellyfish - phase life cycle representatives of the genus Medusozoa, "sea jelly" alternates with an immobile asexual phase of immobile polyps, from which they are formed by budding after maturation.
The name was introduced in the 18th century by Carl Linnaeus, he saw in these strange organisms a certain resemblance to the mythical Gorgon Medusa, due to the presence of tentacles that flutter like hair. With their help, the jellyfish catches small organisms that serve as food for it. The tentacles may look like long or short, spiky threads, but they are all equipped with stinging cells that stun prey and facilitate hunting.
Life cycle of scyphoid: 1-11 - asexual generation (polyp); 11-14 - sexual generation (jellyfish).
Glowing jellyfish
The one who saw how it glows on a dark night sea water, he is unlikely to be able to forget this spectacle: myriads of lights illuminate sea depth shimmer like diamonds. The reason for this amazing phenomenon serve the smallest planktonic organisms, including jellyfish. One of the most beautiful is considered a phosphorus jellyfish. It is not found very often, living in the near-bottom zone off the coast of Japan, Brazil, and Argentina.
The diameter of the umbrella of a luminous jellyfish can reach 15 centimeters. Living in the dark depths, jellyfish are forced to adapt to the conditions, provide food for themselves, so as not to disappear altogether as a species. An interesting fact is that the bodies of jellyfish do not have muscle fibers and cannot resist water flows.
Since the slow-moving jellyfish, floating by the will of the current, cannot keep up with moving crustaceans, small fish or other planktonic inhabitants, you have to go to the trick and force them to swim themselves, right to the predatory open mouth opening. And the best bait in the darkness of the bottom space is light.
The body of a luminous jellyfish contains a pigment - luciferin, which is oxidized under the influence of a special enzyme - luciferase. Bright light attracts victims like moths to a candle flame.
Some types of luminous jellyfish, such as Ratkeya, Equorea, Pelagia, live near the surface of the water, and, gathering in large numbers, they literally words make the sea burn. The amazing ability to emit light has interested scientists. Phosphors have been successfully isolated from the jellyfish genome and introduced into the genomes of other animals. The results were quite unusual: for example, mice whose genotype was changed in this way began to grow green hairs.
Poison jellyfish - Sea Wasp
Today, more than three thousand jellyfish are known, and many of them are far from harmless to humans. Stinging cells, “charged” with poison, have all types of jellyfish. They help to paralyze the victim and deal with it without any problems. Without exaggeration, for divers, swimmers, fishermen is a jellyfish, which is called sea wasp. The main habitat of such jellyfish is warm tropical waters, especially a lot of them near the coast of Australia and Oceania.
Transparent bodies of soft blue color are invisible in the warm water of quiet sandy bays. The small size, namely, up to forty centimeters in diameter, also does not attract special attention. Meanwhile, the poison of one individual is enough to send about fifty people to heaven. Unlike their phosphorescent counterparts, sea wasps can change direction, easily finding careless bathers. The poison that enters the body of the victim causes paralysis of smooth muscles, including the respiratory tract. Being in shallow water, a person has a small chance to escape, but even if medical assistance was provided in a timely manner and the person did not die from suffocation, deep ulcers form at the “bites”, causing severe pain and not healing for many days.
Dangerous little ones - Irukandji jellyfish
Similar action to human body, with the only difference that the degree of damage is not so deep, the tiny Irukandji jellyfish, described by the Australian Jack Barnes in 1964, have. He, as a true scientist, standing up for science, experienced the effect of poison not only on himself, but also on his own son. Symptoms of poisoning - severe headache and muscle pain, convulsions, nausea, drowsiness, loss of consciousness - are not fatal in themselves, but the main risk is a sharp increase blood pressure from a person who personally met Irukandji. If the victim has problems with the cardiovascular system, then the probability of death is quite high. The size of this baby is about 4 centimeters in diameter, but thin spindle-shaped tentacles reach 30-35 centimeters in length.
Bright beauty - jellyfish Physalia
Another inhabitant of tropical waters that is very dangerous for humans is Physalia - the Sea Boat. Her umbrella is painted in bright colors: blue, violet, magenta and floats on the surface of the water, so it is noticeable from afar. Entire colonies of attractive sea "flowers" attract gullible tourists, beckoning them to pick them up as soon as possible. This is where the main danger lurks: long, up to several meters, tentacles are hidden under water, equipped with a huge number of stinging cells. The poison acts very quickly, causing severe burns, paralysis and disruption of the cardiovascular, respiratory and central nervous systems. If the meeting took place at great depths or simply far from the coast, then its outcome can be the saddest.
Giant Jellyfish Nomura - Lion's Mane
The real giant is the Nomura Bell, which is also called the Lion's Mane for some external resemblance to the king of beasts. The diameter of the dome can reach two meters, and the weight of such a "baby" reaches two hundred kilos. Dwells on Far East, in the coastal waters of Japan, off the coast of Korea and China.
A huge hairy ball, falling into the fishing nets, damages them, causing damage to the fishermen and shooting themselves when they try to free themselves. Although their poison is not fatal to humans, meetings with the Lion's Mane rarely take place in a friendly atmosphere.
One of the largest jellyfish is considered Cyanea. Dwelling in cold waters, she reaches largest sizes. The most gigantic specimen was discovered and described by scientists at the end of the 19th century in North America: its dome was 230 centimeters in diameter, and the length of the tentacles was 36.5 meters. There are a lot of tentacles, they are collected in eight groups, each of which has from 60 to 150 pieces. It is characteristic that the dome of the jellyfish is also divided into eight segments, representing a kind of octagonal star. Fortunately, it does not live in the Azov and Black Seas, so you can not be afraid of them when going to the sea to relax.
Depending on the size, the color also changes: large specimens are painted in bright purple or purple, smaller ones are orange, pink or beige. Cyanei live in surface waters, rarely descending into the depths. The poison is not dangerous to humans, causing only an unpleasant burning sensation and blisters on the skin.
The use of jellyfish in cooking
The number of jellyfish living in the seas and oceans globe truly huge, and none of the species is threatened with extinction. Their use is limited by the possibilities of extraction, but people have long been using beneficial features jellyfish for medical purposes and enjoy them palatability in cooking. In Japan, Korea, China, Indonesia, Malaysia and other countries, jellyfish have long been eaten, calling them " crystal meat". Its benefits are due great content protein, albumins, vitamins and amino acids, trace elements. And with proper preparation, it has a very refined taste.
Jellyfish "meat" is added to salads and desserts, to sushi and rolls, soups and main dishes. In a world where population growth steadily threatens the onset of famine, especially in underdeveloped countries, jellyfish protein can be a good help in solving this issue.
Jellyfish in medicine
The use of jellyfish for the manufacture of medicines is typical, to a greater extent, in those countries where their use in food has long ceased to be a subject of surprise. For the most part, these are countries located in the seaside, where jellyfish are directly harvested.
In medicine, preparations containing processed bodies of jellyfish are used to treat infertility, obesity, baldness and gray hair. The poison extracted from stinging cells helps to cope with diseases of the upper respiratory tract and normalize blood pressure.
Modern scientists are struggling to find medicinal product, capable of defeating cancerous tumors, not excluding the possibility that jellyfish will also help in this difficult struggle.
Jellyfish (Polypomedusae) is a representative of the marine fauna. The class of jellyfish, to which the freshwater hydras also belong, consists of many inhabitants of the sea, some of which are very large and conspicuous.
Medusa has a gelatinous, and sometimes almost cartilaginous body in the form of a rain or lady's umbrella with a stalk extending downwards or a bell with a tongue hanging down.
In the umbrella of a jellyfish, one can distinguish between a convex outer or upper side and a concave inner or lower side. From the center of the lower surface of the umbrella of the jellyfish, a very short, sometimes a rather long stalk, which is a mouth tube, goes down; on the lower edge of this tube, protrusions of various sizes are located around the oral opening, which are called oral lobes or oral tentacles.
The edge of the umbrella, equipped on its lower surface with a layer of muscles that serves to reduce the cavity of the bell and at the same time for the movement of the jellyfish, appears either dissected into separate blades, or has the form of a border running in the form of a ring perpendicular to the oral tube. Along the edge of the bell there are usually tentacles or nooses, the number of which is very different, visual, auditory, and sometimes olfactory organs are immediately placed.
The stomach of the jellyfish, which communicates with the mouth by means of a pharyngeal tube, passes into a whole series of radiant canals or elongated pockets heading towards the edge of the bell. Eggs and seed cells develop in the stomach or on the walls of the channels extending from it.
The life cycle of a jellyfish includes the formation of a polyp, then a jellyfish, then another polyp, and so on. As for the polyp, it differs from the medusa in the absence of a bell. Each polyp is represented as a saccular, closed at one end of the body; the closed lower end of such an individual is attached to some foreign object or to a polyp, which sometimes swims freely or is attached to something.
The opposite end of the polyp is usually elongated in the form of a cone and has an opening in the center, called the mouth, surrounded by tentacles. If we imagine that such a polyp, having separated from the object to which it was attached, is somewhat flattened in the dorso-abdominal direction, then we will get a disk with tentacles along the edges and a mouth cone in the middle; from here it is not far to a real jellyfish: it remains only for this disk to become convex and get the shape of a bell or an umbrella.
Thus, the oral canal of the polyp turns into the pharyngeal tube of the jellyfish, and the edge of its oral disk, bordered by tentacles, into the edge of the bell of the jellyfish with its tentacles.
As for the sac-like stomach of the polyp, it turns into water in vascular system jellyfish as follows: its adjacent walls grow together along the periphery for some length with each other, as a result of which radially located channels are obtained. However, polyps differ from jellyfish not only in their structure, but also in other features, the most important of which is their different participation in the reproduction process.
How does a jellyfish reproduce
Jellyfish are organisms that develop sexual products; polyps, which are one of the stages in the development of jellyfish, the stage of the so-called nurse (since they give rise to the jellyfish themselves), reproduce asexually.
The polyps themselves develop from fertilized jellyfish eggs and in turn produce jellyfish asexually. There are, however, jellyfish whose eggs only develop into jellyfish; polyps are also known, giving eggs and seed cells instead of jellyfish. There are various transitions between these two extreme cases. During asexual reproduction, the vast majority of polyps form entire colonies, composed of individual individuals that remain connected to each other; the formation of such colonies is usually for the order of hydroid polyps and hydroid jellyfish (Hydroidea). All these main features of hydroid polyps are also characteristic of freshwater polyps, that is, hydras.
The sexual generation of hydroid polyps are usually hydroid jellyfish, which are characterized by the presence of a membranous rim along the edge of the bell, the so-called sail.
Hydroid jellyfish and polyps
Among the types of hydroid polyps that do not have alternation of generations, i.e., do not develop jellyfish, are freshwater polyps. The so-called sarsia (Sarsia), named after a Swedish naturalist, belongs to the same hydroid polyps; reproduction of species of this genus is associated with alternation of generations.
The tubular sarsia itself (S. tubulosa) has the appearance of slender and slightly branched bushes, 10-15 mm high; its polypiks, club-shaped, are covered with 12-16 tentacles scattered without any order. She lives in the Baltic Sea and settles on the underwater parts of wooden buildings, on sea grass, red algae and the like.
The club-shaped polyps of Sarsia bud off, after a number of changes occurring in them, jellyfish, which are the sexual generation; these jellyfish, reaching 6-8 mm in width, are bell-shaped, equipped with a long oral tube and four long tentacles located along the edge of the bell at an equal distance from one another; a simple eye is placed at the base of each tentacle.
The detachment of hydroid polyps and hydroid jellyfish that has just been described is adjacent to the detachment of floating siphonophores, or tubular polyps (Siphonophora), - free-floating colonies, some members of which are in the form of polyps, others in the form of jellyfish; in such colonies there are, in addition, feeding polyps armed with a long thread - a noose, jellyfish-like individuals that produce egg cells and spermatozoa in themselves, and, finally, some members of the colony turn into apparatuses or into bells that serve to move the colony.
Among the flat siphonophores is the so-called sailboat (Velella); this animal, floating on the sea surface, has a disc-shaped body pierced inside by air channels with a crest standing vertically on its upper surface, which plays the role of a sail: on the underside of the disc in the center there is one large feeding polyp, surrounded by many smaller ones; along the edges of the disc are the tactile members of the colony.
The most famous species of this genus is the common sailboat (Velella spirans), which can often be found very far from the coast, from which it is driven away by the wind; in this animal, at the base of small polypiks, small jellyfish-like creatures bud, which already develop reproductive products and thus serve to reproduce the sailboat.
Another form, the bladder (Physalia), most of the body of which falls on a huge air sac lying horizontally on the water surface; large and small feeding polyps, armed with long lassoes, are placed on the lower surface of the bladder; there are also palps.
Common vesicle (Ph. caravella), with purple, white-speckled polyps and a purple-red air sac, which plays the same role as the scallop of the sailfish, is common in the Mediterranean Sea and the Atlantic Ocean; the dimensions of this form reach 30 cm in length (not counting the lasso, which can be very significantly lengthened).
Classification
Akalef
Representatives of the next order, Acalephae, differ from hydropolyps, hydromedusas and siphonophores, approaching them in the structure of polypoid and medusoid individuals of the entire colony, in the structure of both polyps and jellyfish: jellyfish of this order reach for the most part quite significant sizes and have an umbrella, dissected along the edges into separate lobes.
As for polyps, their characteristic feature is the presence of four correctly located longitudinal swellings that fit on the inner wall of their gastric cavity; 4 bags lie between the indicated swellings.
Reproduction of akalefs
In some cases, a jellyfish immediately develops from a jellyfish egg, but for the most part it turns into a small goblet polyp with tentacles around the oral disc; on such an embryo, sitting motionless on algae, etc., horizontal, one below the other, annular constrictions begin to appear; in this form, the whole embryo is like a stack of plates; soon individual disks - future jellyfish - bud off one after another and, floating freely, turn into sexually mature forms.
The suborder of broad-tentacled akalefs (Semostomae), characterized by the presence of 4 long, boat-shaped simple tentacles located around the cruciform mouth, belongs to the very common in the Baltic and in general in European seas, the eared jellyfish Aurelia aurita (Aurelia aurita); it is distinguished by a flat, like a watch glass, and sometimes a hemispherical umbrella and narrow, lanceolate, strongly layered at the edges, but not lobed tentacles.
This form, often found in huge masses, is well known to all explorers of our seas; the size of the eared jellyfish ranges between 1 and 40 cm in diameter, but specimens of 5-10 cm are most often found.
Another well-known jellyfish from the Akalefs is the hairy jellyfish (Cyanea capillata), characteristic of the northern European seas. Like other species of this genus, the described jellyfish is distinguished by the edge of the bell dissected into 8 main lobes and the presence on its lower surface of many long tentacles - nooses.
The described jellyfish appears in autumn, like an eared jellyfish, in masses; its main color is yellow-brown, sometimes reddish-yellow; in diameter reaches 30-60 cm, but there are specimens more than 1 m in diameter and with tentacles more than 2 m long.
Even larger, i.e., over 2 m in diameter, reaches the northern hairy jellyfish (C. arctica), the length of the tentacles of this species sometimes exceeds 4 m. This jellyfish is thus the largest of all jellyfish known to us.
Corner jellyfish
As for the root-mouthed jellyfish (Rhizostomeae), they differ from the previous ones in the presence of 8 long root-shaped mouth tentacles arranged in pairs; these tentacles in most cases grow together in pairs, and the mouth is completely closed and its role is played by many small sucking holes located along the tentacles.
Between these stomata, these jellyfish often have more or less numerous mouth palps, with button-like thickenings at the ends.
Kotilorhiza
An example of such a jellyfish is the Mediterranean cotylorhiza (Cotylorhiza tuberculata), it is a yellowish jellyfish in general, 10-20 cm wide in diameter with long sucking tubes or suckers on long legs; the edges of the disk of this jellyfish are spotted with white spots, the oral disk is meaty red or yellowish-brown; milky-white tentacles, which, however, can sometimes be amber-yellow, brown, purple or blue, like violet, scallops surrounding the sucking holes - these are the features that describe the described jellyfish in more detail.
discoid jellyfish
Both of the mentioned groups of jellyfish, broad-tentacled and corner-mouthed, constitute a suborder of disc-shaped jellyfish (Discomedusae), the characteristic features of which are: a flat, mostly disc-shaped bell or umbrella, usually with 8 marginal sense organs; the edge of the bell is cut into at least 16 blades; the stomach is surrounded by 8, 16, 32, or even a large number stomach bags; on the lower wall of the stomach are the sex glands, very clearly visible in our eared jellyfish and called eyes in the common people.
Cuboid jellyfish
The next group of cuboid jellyfish (Cubomedusae) is defined by the following features: a tall, cubic umbrella, the edge of which, resembling the swimming rim of hydroid jellyfish, is in the form of a horizontally tense or hanging down membrane; on this edge there are 4 sensitive flasks, with an eye and an organ of hearing on each.
A representative of this group is the Mediterranean common cube-shaped jellyfish (Charybdea marsupialis), which is 2-3 cm wide and 3-4 cm high; this species, as well as other species of the same genus, is interesting for its unusually highly differentiated eyes, the structure of which resembles that of the eyes of vertebrates.
Jellyfish sea wasp
The sea wasp jellyfish is the most poisonous jellyfish in the world, it lives off the coast of Thailand and Australia. Its body is vitreous - cube-shaped, that is, this jellyfish belongs to cuboid jellyfish. Its stinging cells leave deadly burns. As a result of which death can occur within 3 minutes.
However, there are survivors - these are people with a strong heart. There is an antidote against the burns of the sea wasp jellyfish, but you must have it with you, since from the moment of the burn the victim has no more than 3 minutes to save his life. Therefore, you should swim only in places specially fenced off from jellyfish, but if you decide to swim in the open ocean, then have an antidote with you.
goblet jellyfish
Finally, last group goblet jellyfish (Stauromedusae), characterized by the presence of a leg at the top of the goblet umbrella, with which the jellyfish is attached to algae, etc .; tentacles, mostly in bundles, sit on these jellyfish along the edge of the bell.
Lantern
The described suborder includes, among other things, the lantern (Lucernaria), belonging mainly to the northern seas; this form can move from place to place with the help of its tentacles, which is also helped by the leg of the jellyfish, which has the ability to arbitrarily attach or separate from underwater objects.
In the northern European, as well as in the Black and Baltic Seas, the largest (up to 7 cm) is found and a long time ago known species of the genus described is the common lantern (L. quadri-cornis): this gray, green, brown-yellow or, finally, black-brown jellyfish willingly settles on red algae. It is also known on the shores of Greenland and found in America, off its northeastern shores.
Read more about jellyfish -
Watch a video about jellyfish:
Jellyfish are a very common and most amazing species of living creatures that inhabit the seas and oceans. They can be admired endlessly. What types of jellyfish are, where they live, what they look like, read in this article.
General information about jellyfish
They belong to the coelenterates and are part of their life cycle, which has two stages: asexual and sexual. Jellyfish adults are dioecious, their reproduction occurs sexually. The role of the male is to sweep the reproductive products into the water, which can immediately enter the corresponding organs of the female or be fertilized directly in the water. It depends on the type of jellyfish. The larvae that emerge are called planulae.
They have the ability to exhibit phototaxis, that is, they move towards a light source. Obviously, they need to be in the water for some time, and not immediately fall to the bottom. The free-moving life of the planula does not last long, about a week. After that, they begin to settle to the very bottom, where they attach to the substrate. Here they are transformed into a polyp or scyphistoma, the reproduction of which occurs by budding.
This is called asexual reproduction, which can be carried out indefinitely until favorable conditions for the formation of jellyfish come. Gradually, the body of the polyp acquires transverse constrictions, then the process of strobilization occurs and the formation of young disk jellyfish - ethers.
They are the majority of the plankton. Subsequently, they grow up and become adult jellyfish. Thus, for asexual reproduction - budding, the water temperature may be low. But, having overcome a certain temperature barrier, dioecious jellyfish are formed.
Class of hydroid jellyfish
Coelenterates include solitary or colonial aquatic inhabitants. Almost all of them are predators. Their food is plankton, fish larvae and fry. Intestinal species of jellyfish number ten thousand species. They are divided into classes: hydroid, scyphoid and The first two classes are usually combined into a subspecies of jellyfish.
Hydroid intestinal jellyfish are characteristic representatives of freshwater polyps. Their habitats are lakes, ponds and rivers. The body has a cylindrical shape and the sole is attached to the substrate. The opposite end is crowned with a mouth with tentacles located around it. Fertilization takes place inside the body. If the hydra is cut into many pieces or turned inside out, it will continue to grow and live. The length of her body is green or brown in color reaches one centimeter. The hydra does not live long, only one year.
They are free-floating and have different sizes. The size of some species is only a few millimeters, while others are two to three meters. An example is cyanide. Its tentacles can stretch up to twenty meters in length. The polyp is poorly developed or completely absent. The intestinal cavity is divided into chambers by partitions.
Scyphoid jellyfish can live up to several months. Approximately two hundred species inhabit the temperate and tropical waters of the oceans. There are some jellyfish that people eat. These are cornerots and aurelias, they are salted. Many types of scyphoid jellyfish cause burns and redness of the body if touched. For example, hirodrofus causes even fatal burns in humans.
Medusa Aurelia eared
There are different types jellyfish A photo of one of them is presented to your attention. This is a scyphoid eared. Her breath is carried out by the entire transparent and gelatinous body, in which there are twenty-four eyes. Along the entire perimeter of the body are sensitive little bodies - ropalia. They receive impulses environment. It could be light.
The jellyfish consumes food and removes its remains from the body through the mouth opening, around which there are four oral lobes. They contain a burning substance that serves as a defense for the jellyfish and helps to get food. Aurelia is not adapted to life on land, as it consists of water.
Medusa Cornerot
It is popularly called "Umbrella". Jellyfish habitat - Black, Azov and Baltic Sea. Cornerot captivates with its beauty. The body of the jellyfish is translucent with a blue or purple edging, reminiscent of a lampshade or umbrella. Its peculiarity is that most often it swims on its side and does not have a mouth. Instead, small diameter holes are scattered on the blades through which it feeds. Cornerot lives and breeds in the water at great depths. In case of accidental contact with a jellyfish, you can get burned.
Unusual habitat
Scientists from Israel have proven that freshwater jellyfish are found in the Golan Heights in lakes. Children saw them for the first time. Then individual copies were placed in a bottle and handed over to Professor Gofen. He carefully studied them in the laboratory. It turned out that this is a local colony of one of the freshwater hydroid jellyfish, which were described in England as early as 1880. Then these jellyfish were found in a pool with aquatic tropical plants. According to the professor, the mouth opening of the jellyfish is surrounded by numerous stinging cells, with which it catches planktonic organisms. For humans, these jellyfish are not dangerous.
Jellyfish freshwater
These intestinal inhabitants inhabit the waters only of the seas and oceans. But, there is one exception, called the Amazonian freshwater jellyfish. Its habitat is South America, namely the pool major river on the mainland - the Amazon. Hence the name. Today, this species has spread everywhere, and quite by accident, during the transport of fish from the seas and oceans. The jellyfish is very small, reaching only two centimeters in diameter. Now it inhabits slow, calm and stagnant waters, dams, canals. Food is zooplankton.
The biggest jellyfish
This is cyanide or lion's mane. In nature, there are different types of jellyfish, but this one is special. After all, it was her who was described by Conan Doyle in his story. This is a very large jellyfish, whose umbrella reaches two meters in diameter, and twenty tentacles. They look like a tangled ball of crimson red.
In the central part, the umbrella is yellowish, and its edges are dark red. The lower part of the dome is endowed with a mouth opening, around which there are sixteen large folded oral lobes. They hang down like curtains. Cyanea moves very slowly, mainly on the surface of the water. It is an active predator, feeding on planktonic organisms and small jellyfish. Habitat - cold waters. Common, but not dangerous. The resulting burns do not lead to lethal outcome but may cause painful redness.
Jellyfish "Purple Sting"
This species is distributed in the World Ocean with warm and temperate waters: it is found in the Mediterranean and in the Atlantic and Pacific Oceans. These types of jellyfish usually live far from the coast. But sometimes they can form flocks in the coastal waters, and meet in large numbers on the beaches. Jellyfish have not only They are golden yellow or yellow-brown, depending on their habitat.
Jellyfish Compass
These types of jellyfish chose their place of residence coastal waters the Mediterranean Sea and one of the oceans - the Atlantic. They live off the coast of Turkey and the United Kingdom. These are quite large jellyfish, their diameter reaches thirty centimeters. They have twenty-four tentacles, which are arranged in groups of three each. The color of the body is yellowish-white with a brown tint, and its shape resembles a saucer-bell, in which thirty-two lobes are defined, which are colored brown along the edges.
The upper surface of the bell has sixteen V-shaped brown rays. The lower part of the bell is the location of the mouth opening, surrounded by four tentacles. These poisons are potent and often result in wounds that are very painful and take a long time to heal.
Hello my Dear friends! In order to maintain our erudition at the proper level and not let us relax over the summer, I propose a topic from the field of knowledge. The material will later be useful to our children in the lessons of the world around them.
And today we will talk about sea jellyfish. Do you agree? Moreover, for those who have a trip to the sea ahead, it may be interesting to combine theory with practice by getting acquainted with these amazing inhabitants closer to the water element.
Lesson plan:
Who is she, unknown animal?
Marine animals with streamlined shapes, outwardly similar to an umbrella, with many tentacles have been living among us for a long time. The name of these maritime miracles was given in the 18th century by Carl Linnaeus, who was well acquainted with the Homeric legends about the mythical gorgon Medusa.
He noticed a certain resemblance to the head of this evil ancient Greek maiden, whose hair was composed of many moving snakes. It is because of this similarity of tentacles with her head that the animal got its name.
And today, those who have been to the sea more than once, probably met with them in the process, trying to swim around this creature side. And all because jellyfish have special stinging cells with which they “bite” painfully, mercilessly burning us, well, their prey at the same time and predators attacking them.
Do you know that?! Medusa with unusual name Turitopsis Nutricula is considered the only immortal creature of its kind on our planet. And on average, almost all jellyfish live no longer than six months, centenarians exist up to three years. Only a few species do not die, but are reborn into a new living organism.
In the language of zoologists, these Marine life- none other than intestinal animals that are part of the group of multicellular invertebrates. That is why they spread so shapelessly like jelly, falling on a hard surface or in our hands - there is nothing to hold on to the fabrics!
What, what, what are our jellyfish made of?
What is a skeletal jellyfish made of? Yes, from the water! And by 98 percent! Therefore, if you put it to bask in the sun, then almost all of it will melt - it will dry out. And muscles help her move in the water.
From the edges of the body of the jellyfish are tentacles. They can be long and thin, some have short thick “legs”. According to these same tentacles, zoologists divide them into species. But no matter how many "legs" this invertebrate has - four or one hundred and four - their number is always a multiple of four. Why? This is how nature arranged it - this feature is called radial symmetry in such representatives of animals.
It is on these very tentacles that those ill-fated stinging cells containing burning poison are located.
Do you know that?! The jellyfish with the name Sea wasp is considered the most poisonous in the world among its relatives. This basketball-sized invertebrate nipper is so powerful that it can kill 60 people in a couple of minutes!
Medusa breathes underwater with her whole body, and looks at others with 24 eyes at once, which are light-sensitive cells. True, scientists say that these invertebrates cannot distinguish objects, but they are able to distinguish light from darkness.
But thanks to these special cells, many specimens glow beautifully in the dark. Those that live higher to the surface of the water know how to wink in red, and those that prefer to hide at a depth warn of their presence more often with blue light.
Jellyfish also have mouths. It is located in the lower part and may look like a tube for some, like a mace for others, and for others it can simply be a wide hole. By the way, through which the jellyfish eats, through which it throws the remnants of food into the water.
A jellyfish has a lot of things, but there is no brain! Nature did not reward the primitive being created by it with the ability to think, think, dream, and did not give sense organs either.
How does a jellyfish live?
Jellyfish can live exclusively in salt water, so you will never meet them in fresh rivers and lakes. But the oceans and seas, and not necessarily warm at all, there are those that like colder water - these are their favorite place residence.
This creature grows throughout its unconscious life and, depending on the species, it can be small, only a few millimeters, or huge, as much as two meters. The weight of some individual specimens can be several centners! Such a straight Bolshukhansky floating jellied meat!
Do you know that?! If you measure the size of a resident of the Northwest Atlantic called Cyanea (in English Cynea) along with e tentacles, then we get a figure of almost 40! meters.
This creature without brains and skeleton is a real predator! Most large sizes They catch small fish and even eat their own relatives. Smaller specimens are content with crustaceans and fish fry and caviar. “How is it that a jellyfish that does not distinguish any outlines is looking for food?” - you ask. With the help of those very terrible and dangerous stinging cells on the tentacles, which catch touches and without thinking, since they have nothing to think about, they instantly inject poison into the victim. Medusa thus paralyzes prey, and then begins to regale.
Now you understand that when you touch the body of a jellyfish while swimming, in the first seconds it sees another lunch or dinner in you, burning with poison! Some use their tentacles as a net to catch their prey.
Scientists have noticed that jellyfish are by nature loners. Of course, who would be friends with such gorgons! If you see colonies of accumulated umbrella hats, then they have gathered together not at all because they want to "drink tea and talk." They just got bogged down by the currents of water. So they prefer to keep their distance from each other.
What are jellyfish?
As we have already mentioned, they are divided into species by tentacles. So, here are their families.
In total, in the nature of the world's oceans, there are more than two hundred varieties of jellyfish of all shapes and colors. There are completely transparent, and red, and purple, and even spotted and striped, but there are no green ones! Why is unclear...
In general, these natural creatures surprisingly beautiful, especially when they are slowly floating through the water column, to watch from the side. Doubt? Rather, go to the aquarium and admire this beauty. No side by side? Then the Internet will always help you to touch the beautiful at a distance of thousands of kilometers!
For today, probably, erudition is enough?! It's time to relax, because it's still summer!
Although a video about jellyfish, most likely, will not hurt)
Have a great August!
