Some of the beautiful animals that do not meet on land are starfish. Divers performing dive in the warm seas often manage to admire these unusual and interesting creatures.

Icharkin (Echinodermata) to which starfish includes an independent and very peculiar type of animal world. According to the structure of the body, they are completely different from other animals and, thanks to the peculiarities of the organization and the original body shape, have long been attracted attention.

Icharkin appeared on Earth for a very long time, more than 500 million years ago. The presence of a lime skeleton contributed to the good preservation of fossil remains of the ancestors of these creatures.
In the glorious and numerous community, the Sea Stars (Asteroidea) class is represented by a huge variety of species that differ from each other with dimensions, body shape and some differences in the organization.

And at the end of the post you can see interesting in my opinion video how to hang out and how the stars eat.

In the fossil state, they are known since the days of the Nizhny Paleozoic - from the Ordovikov period, i.e. About 400 million years ago. Currently, more than 1,500 modern seeding species, which are systematized, approximately 300 genera and 30 families are known. On the number of units of marine stars between scientists often disagree. Previously, they were united in three detachments - the applaply, needle and pedalishing stars. Currently, they are divided into 5-9 different detachments in various sources. I think that for us with you is not very important.

Sea stars - exclusively marine animals, are not found in fresh reservoirs. They do not live in highly desalinated seas, for example, in Azov or Caspian, although sometimes can be represented by single oppressed species. For example, the individuals of A.rubens stars occur sometimes in the western part of the Baltic Sea (at the island of Rügen), but here they do not multiply, and the population of these marine stars is maintained by communimal flows of larvae. And the only starfish, penetrated from the Mediterranean Sea to Black - Marthasterias Glacialis, lives only in the most salty of it - in the Bosphorus Strait area.

In the seas and oceans with the normal salinity of water, starfishes are found everywhere - from the Arctic to Antarctic and, especially numerous, in warm waters of the seas. The deep habitat of marine stars is also wide - from the surface layers of the sea, to kilometer depths, although, of course, at high depths, species diversity and the number of marine stars are more scarce.
About 150 species of marine stars live in Russian seas who live in a very rare exception, in the Northern and Far Eastern seas.

All starfish in an adult state lead a bottom lifestyle, crawling along the bottom surface or burning into the ground. Many of the nautical stars, especially inhabited in coastal shallow water - active predators who eaten by various small bottom organisms - molluscs, crustaceans, other invertebrates, including ocheroki, and even fish. Do not be broat and padal.
Among the deep-sea sea stars, Iloid dominate - they use sea soil in food, removing the organic out of it. Some starfishes can be used in Food Plankton.

Usually, starfishes are not very picky for food and absorb everything that can absorb. In the diet, for example, the Chilean star MEYENASTER is increasing to 40 species of Iglinodi and mollusks.
Most starfish reveals prey and determines its location due to substances that the victim sends into water. Some starfish living on a soft day, including types of Luidia and Astropecen, are able to find a sacrifice and then dig a substrate to get to mining. Stylasterias Forreri and Astrometis Sertulifera from the west coast of the United States of America, as well as Leptasterias Tenera - from the east coast - enough small fish, amphipod and crabs of pedies, when the victim stops over the sea star or nearby.

Interesting way to eat by the sea stars of many types of bivalve mollusks. The star crashes on the body of such a production and attached to it with its legs on the rays, giving some effort towards the opening of mollusk shell sash. Gradually, the mollusk muscles that hold the sink sash in the closed state are tired and open the sink. The starfish turns inside out the stomach and wures it into the gap between the sash, starting to the meal right inside the mollusk shell. Food is digested in this way in a few hours.

The stomach inside is insideide is a unique nutritional body for many starfish. Patiria Miniata starfish from the west coast of America, for example, spreads his stomach along the bottom, digesting the organic matter.

Sea stars usually have a more or less flattened body with a central disk, gradually turning into the radially divergers from it rays. The oral opening is located on the bottom (oral) side of the disk of the sea star. Most stars on the top of the body are an anal hole, some species are missing at all. In the middle of the lower side of each beam passes a furrow, in which there are many soft and moving outgrowths - an ambulapral legs, with which the starfish moves along the bottom. Typical for marine stars is a five-way structure, but there are stars having 6 or more rays. For example, at the solar star of Heliaster 50 rays.

Sometimes the number of rays is different even in individuals of one species. So, in our northern and Far Eastern seas of the sea star Crossaster Papposus, the number of rays ranges from 8 to 16.
The ratio of the length of the rays and the diameter of the disk is also different. In some deep-water sea stars, the length of the rays is 20-30 times the diameter of the disk, at the same time, in the ordinary in the Japanese Sea of \u200b\u200bPatiria Pectinifera, the rays are only slightly issued beyond the disk, because of which the star has the form of the right pentagon . These stars are also called biscuit for similarity with flat biscuits.

Also known even starfish, whose appearance is so changed that it is difficult to recognize the star in them. In the usual inhabitant of coral reefs of Novoguinea Kulcitis (Culcita NovaEguineae), a strongly blurred body resembling the shape of a very swollen pillow or a bun. However, such a shape of the body is only in adult stars - young coffers have the form of the right pentagons.
Usually, starfish, living in small depths, have a very diverse color of the upper body. Here are the most different colors and shades of the spectrum. Sometimes the color is spotted and form a quaint drawing. The abdominal side of the bodies of marine stars has a more modest color, usually it happens pale yellow.

Coloring stars living at large depths is also more pale - usually dirty gray or with shades of gray colors. Some (eg brisinga) have the ability to glow.
A variety of color of marine stars depends on pigment inclusions that are in the cathoxes of the skin epithelium.
The dimensions of various types of marine stars can vary from several centimeters to 1 meter. Most often, divers meet starfish in size of 10-15 cm.
The life expectancy of marine stars of some species can be more than 30 years.
The sense of seating authorities are developed weakly and are represented by red eye stains located on the tips of the rays and tactile receptors on the skin.

At first glance at the maritime star, first of all, notice numerous, located on the surface of the body, elements of a lime skeleton - plates, needles, spikes, tubercles, etc. But in fact, the skeleton of marine stars is not outer, like mollusks or arthropods, but is under the skin epithelium, sometimes very thin. Lime plates of marine stars do not form a single solid skeleton, and attached to each other with the help of connective tissue and muscles. Sea stars have the main skeleton, called the support and various appendages to it - spikes, tubercles and grows that have a protective function. Sometimes such spines and bristles form solid cover on the upper side of the bodies of marine stars.

The reproduction of marine stars can be held in several scenarios. If the starfire to tear off the beam with a part of the disk, then two individuals are formed from the resulting pieces of the star. Time for such regeneration can be up to 1 year. Some starfishes and multiply such a regenerative way. In their body there is a softening of the connective tissue and they disintegrate into several parts, more often for two. Soon of these parts will grow independent starfishes. Types of marine stars of Lincia (LincKia), ordinary in the Pacific Ocean and other areas of the World Ocean, are unique in their ability to discard the rays entirely. From each such rach, if it is not eaten by a predator, a new starfish can be regenerated. Such reproduction is called cans.

Sea stars multiply and sexual. Most of the species of sedaplands, i.e. Posted by male and female individuals. The reproduction is carried out by the fertilization of the eggs of females by the genital products of males, which are removed directly into sea water. The marine star female can take several million eggs at times.
There are also same-sex (hermaphridal) views. This species belongs, for example, the usual European Star star Asterina Gibbosa, which is hermaphrodite. These stars in the body are also produced by women and men's sex products. The young people, usually, are trimmed in a special output bag or cavities on the back.
The larvae hatched from eggs feed, usually, plankton and ground, fall on the bottom, turning to the usual lifestyle for marine stars

Natural enemies have nautical stars. These animals contain poisonous substances in the body - asterosaponins, so predators do not receive them attentive. In addition, there are few nutrients in the bodies of the sea star and they are not calorie food.

Ternoecency

A large sea star is often found on the coral reefs of the Pacific and Indian Oceans, a large maritime star is a crown or Akantaster (Acanthaster Plansi), reaching 50 cm in diameter and belonging to the genus Akantasteride.
It is usually assumed that the starfish is completely harmless to humans, however, a careless handling of a throat crown can lead to serious trouble. The maritime star The crown is a bad glory among the inhabitants of many tropical islands. It is impossible to take it in the hands, without having received the burning pain of the numerous needles covering the body of the starfish.
Many trouble delivers a crown of the crown of divers for pearls - if the swimmer comes by chance on the body of the Akantaster, then his needles pierce the foot and rolled in the human body, infecting blood to poisonous discharge

Local residents believe that the victim should immediately turn over the throat crown of the stroke and attach a foot to his mouth hole. It is believed that the star sucks the fragments of his needles from the body of a man, after which the wounds quickly heal.

The crown, or the Akantaster is known for another unpleasant property. He extremely likes to eat coral polyps, destroying, thereby, the reef itself and leaving no food and the shelter of its inhabitants. In different years, there were outbreaks of a significant increase in the number of these marine stars in some regions. Then the very existence of reefs and their inhabitants were threatened.

Significant human resources were thrown on the fight against the throat crowns. The stars were collected in the basket and destroyed, but it did not give a tangible effect. Fortunately, the outbreak of the number of thorns of the crowns soon ceased and coral reefs did not die completely.
Some starfishes cause damage, destroying the fishing grounds and plantations of oysters and mussels. Such pests are collected by special gears from fishing territories and destroy.

It should be noted and a useful role played by starfish in the ecology of the World Ocean, and the planet as a whole. These creatures are absorbed intensively and dispose of carbon dioxide, which in the land atmosphere it becomes more and more more and more. Every year, by sea stars, up to 2% carbon dioxide of the atmosphere is disposed of. This is a very big digit.
In addition, starfishes are seabed sanitary panels, entering the palm and the remains of the dead maritime organisms, as well as weaker and sick individuals of marine animals.

Interesting Facts:

The largest of 1600 varieties of marine stars on the general scope, the tentacle is considered very fragile Midgardia Xandaros.. In the summer of 1968, the representative of this species was caught in the southern part of the Mexican Bay by the Research Ship "Adaminos" Texas University. Its length, together with tentacles, was 1380 mm, but the diameter of her body without a tentacle reached only 26 mm. In the dried form, it weighed 70.
It is believed that the maximum weight of all marine stars has a five-pointed Thromidia Catalai.living in the western part of the Pacific Ocean. The representative of this species caught on September 14, 1969 in the area of \u200b\u200bAudi Aidi in New Caledonia and put up later in the aquarium Noomea, weighed 6 kg, and the scope of her supreets reached 630 mm
The most small from the famous marine star asteride ( Patmella Parvivipara.), found by Wolf Zaydler on the West Coast of the Eyre Peninsula, South Australia, in 1975, it had a maximum radius of 4.7 mm, and the diameter is less than 9 mm.
The most predatory sea star in the world is considered the "crown" ( Acanthaster Planci.), dwelling in the pools of the Pacific and Indian Oceans, as well as in the Red Sea. It has the ability to destroy up to 300-400 square centimeters of corals per day.
The maximum depth on which the seaside avead can be detected is considered to be 7584 m. At this depth of the Soviet research vessel "Vityaz" approximately in 1962 in the Mariana Wpadine (Western Pacific) was detected Porcellanaster Ivanovi..

Sea Star has small areas on the tip of each beam of the stars, which act as photosensitive sensors and contain a red pigment that changes its color. It is assumed that these sites (flies) affect the movement of the sea star.

The starfish can eat, not swallowing food. For example, encountered a double mollusk, it worst it and turns inside out the lower stomach. He penetrates the sink, envelops the soft pieces of mollusk and digested, and then the starfish simply draws into the liquefied solution. We act like a similar way - however, they do not know how to turn the stomach, but they simply injure digestive juice.

Sea stars - animals with an unusual body shape, thanks to which they paid attention to people still in ancient times. Sea stars belong to the type of iglozzy, in which they are highlighted in a separate class, which has almost 1600 species. The nearest relatives of these invertebrates are very similar to them, or snakes, and more far aschoturia and sea hedgehogs.

The main distinguishing feature of the marine stars is, of course, body shape. In general, the body of marine stars can be divided into the central part - the disk, and the side grows that are called rays or hands. This animal is characterized by radial symmetry, so their body is divided into symmetric sectors, the number of which is usually equal to five. However, among maritime stars there are organisms with a large number of symmetry axes: some species have their number to reach 6-12 and even 45-50.

Nine Star Star Salast Endeca.

Each sector, respectively, includes a part of the central disk and hand. It would seem that such a one-type structure should be poured out in the monotony of these living organisms. But just a shape of the body from marine stars is very volatile. Firstly, the relative length and thickness of the rays will vary greatly: in some species, they are elongated and thin, others have a triangular shape, sharply narrowing towards an end, third rays are so short that they practically do not protrude beyond the edges of the central disk. Stars of the last type have a very high central disk, so they resemble pillows. Thus, most of the types of marine stars are the length of the rays, the diameter of the central disk is 3-5 times, in the longest 20-30 times, and the pillows tend to zero.

This bright ottoman on the seabed is actually a starfish of Kulzit Novoguinskaya (Sulcita NovaEguineae).

Secondly, starfish is distinguished by the texture of the surface and the color. Here, a variety is simply not amenable to descriptions - smooth, spikey, spiny, rough, velvety, mosaic; Monochrome and pattern, bright and faded. The color gamut of these animals includes almost all colors, but most often there are various shades of red, less often blue, brown, pink, purple, yellow, black colors. Pale starfishes usually live at depth, and shallow species are bright.

This is the same Novoguinee Koltification, but another coloring.

At first glance, starfishes seem primitive, because they do not have any noticeable senses, brain, weakly differentiated internal organs, but this simplicity is deceptive.

LINCKIA LINCKIA LAEVIGATA star (Linckia Laevigata), her rays look like sausages.

First of all, it should be noted that marine stars have an inner skeleton. They do not have a spine and separate bones, but there are many limestone plates connected to each other in the openwork system.

Openwork plexus of skeletal elements on the surface of the sea star.

A young starfish has skeletal elements hidden under the skin, but over time, the skin over some lime spikes is erased and they become visible outside. It is these spikes that give the sea stars a prickly look.

The spikes on the surface of the sea star are covered with skin, but some of them have already been exposed and has a brilliant surface.

In addition, on the upper side of the body, many species can see lime plates, merged together or forming a network.

The bizarre pattern formed by the skin and skeletal elements of the starfish.

Finally, the third element affecting the appearance of the sea star is a pedalcing. Pedicellers are modified needles similar to tiny tweezers. In the life of a starfish, they play an important role, with their help it cleans the top side of the body from garbage and sand. All skeletal elements are interconnected by the muscles, so after the death of the starfish, its core is crumbling on lime records and there is no trace from the animal.

Akantster starfish, or a crown (Acanthaster Ellisii) has spiny and poisonous spikes.

The muscular system of marine stars is developed relatively weak. Each ray has a muscular litigation that can bend the beam up, this, actually, muscle movements of stars and are limited. But not limited to mobility at all. Sea stars can crawl, dig, bending, swim, but they do it not with the help of muscles.

Sea stars Screwdrivers (Patiria Pectinifera) scrambled along algae.

These animals have a special body system - ambulacral. In fact, this system is a channels and cavities connected together and filled with liquid. The starfish can pump this liquid from one part of the system to another, due to which its parts of the body bend and move. The central detail of this system is the ambulatal legs - tiny blind growing outlacral channels on the underside of the starfish. Each leg is moving independently of others, but their actions are always consistent. With the help of these microscopic elements, the starfish is able to work wonders. For example, it is capable of climbing the vertical surface, it can stick to the glass of the aquarium for a long time, it can get up on the rash, extinguishing like a frightened cat, and maybe grabbing two rays, push the sash of the mollusk sink. And all this makes the animal practically deprived of the brain and eyes!

On the underside of the beam are visible translucent ambulatal legs.

For the sake of fairness it is worth noting that some senses of the marine stars are still there. These are eyes located at the ends of each beam. Eyes are very primitive and distinguished only light and darkness, seaside items do not see items. Sea stars are able to capture chemicals (analogue of the scent), only they feel them in different ways. Some species are very sensitive and can change the lures on the smell for several days, others can spit past the victims in a pair of centimeters and do not teach it. Very developed by marine stars, touching, they try to get rid of sand, which falls asleep on top, and also always strive to feel their way with the help of small tental at the end of each beam. The touch suggests the marine star with whom she collided - victim or predator. The brain of the starfish replaces the group weakly interconnected cells. It is surprising that despite such a primitive structure of the nervous system, starfishes can produce elementary conditional reflexes. For example, starfish, which were often caught with networks, began to get out of them faster than those who were caught for the first time.

At the end of the beam of the starfish asterodiscus (Asterodiscus Truncatus) is visible from the eye. The beam itself is covered with embossed limestone plates.

Another "strong", in the literal and figurative sense of the word, the system of marine stars is digestive. These animals are located in the center of the disk on the underside, and the tiny anal hole on the dorsal side of the body. By the way, they are rarely engaged in them (some species will overgrow it at all), preferring to remove food residues through the mouth. The stomach of nautical stars has grown extending in the rays, in these growths, reserves of nutrients in case of hunger are postponed. And starving starfishes regularly, as it stops to eat during breeding. The stomach in many species can be turned out through the oral hole, and it is stretched as rubber, taking any form. Thanks to the tensile stomach, the starfish can digest production exceeding it in size. The case is known when Luidi's starfish swallowed so much sea hedgehog that he died, failing to spit his remnants.

In the middle of the central disk of frome monilis, a tiny anal hole is visible.

Other organism systems are developed at sea stars weakly. They breathe through special skin grows on the top, washed by sea currents, body side. The gills and lungs do not have, so the starfish is sensitive to the lack of oxygen. They also do not endure the desalination of water, so they are found only in the seas and oceans. The sizes of marine stars range from 1-1.5 cm at a miniature ball of the peciferator to 80-90 cm at the marine star of Frayell.

The name of this starfish speaks for itself - elegant ferrom (fromia elegans).

Sea stars have global distribution. They meet everywhere in all seas and oceans from the tropics to the poles. Of course, in warm waters, species diversity is higher than in cold. Most species prefer to live in shallow water, some even find themselves on the shore during the sings. But among these animals there are deep-water species, including those who live in depths of over 9 km!

Sea stars in shallow water.

The starfish most of the time is crawled along the bottom, they make it very slowly, the usual speed of the marine star of the middle size is 10 cm per minute, but the starfish can and "hurry" at a speed of 25-30 cm per minute. If necessary, starfish can climb stones, corals, algae. If the starfish falls on the back, then she immediately turns over the abdominal side down. For this purpose, the animal bends two beams so that the ambulatal legs on the bottom touch the ground, and then the starfish turns the body and takes the usual position. Some species are capable of even clumsy floating for short distances. Sea stars can be called saddled animals, the lavety animals showed that they are not deleted by more than 500 m from the site of the initial catch.

Marine Star Granular Granulatus (Coriaster Granulatus) looks like a bun.

Despite the external primitiveness and apparent helplessness starfish Terrible predators. They are quite voracious and never refuse mining, with the exception of the caviar tooling period. Only deep-water species feed on the shelter, from which they remove the dietary particles, conditionally "unsubstantial" can be called the naval stars of the chest, which prefer to emblorict fouling on corals. All other species are actively hunting for other animals.

Not at all, the romantic relationships began between the sea star Solyster (Solaster Dawsoni) and the Hippasteria Spinosa Hippasteria.

Most sea stars are unschrenadable, they eat all that they are able to keep them with their own hands and how to get their "rubber" stomach, not Brozdy and Padal. Some species can be powered only by a certain kind of feed: sponges, corals, brickeloous mollusks.

Pentagonaster Pretagonaster's starfish (Pentagonaster Pulchellus), which is also called a biscuit marine star for the body shape resembling cookies.

The favorite extraction of nautical stars are the same as they themselves are laid animals - sea hedgehogs and bivalve mollusks. Sea hedgehog star overtakes a crawl and eats his mouth. Bivalve mollusks have sinks whose flaps they are tightly closed in case of danger, therefore, starfishes are accepted with them otherwise. First, the starfish is glued with two rays to the sinks of the shell, and then begins to push them. It must be said that the ambulapral legs are firmly glued to the substrate due to the adhesive lubricant and one single outlacral leg can develop an effort to 30 g! And on each ray of the starfish of their hundreds, therefore, the star, like a salary, spreads the shells with a slightly kilogram. However, it is not necessary to push the sash to the sink of the shell in full swing, for a satisfying dinner it is enough to crack 0.1 mm! In this truly microscopic gap, the starfish turns its stomach (it can stretch 10 cm) and digested the mollusk in his own home.

Asterias Rubens Star (Asterias Rubens) pulls her hand to mollusk.

Most seaside stars separately, very few species have both men's and female sex glands. Sex glands are located in pairs at the base of each beam. The sea star Asterina has young individuals at first male, and then change it to female. A special exception is the starfish of an officer, who has males ... no at all. The females of this species are laying off caviar without fertilization, such a reproduction is called parthenogenesis. During the mating, males and females join their rays and swell cum and eggs into the water. The amount of eggs depends on the type of the development of the larvae and fluctuates from 200 in those species that are tolerated offspring, and up to 2-200 million in species with free-laying larvae.

Pairing of marine stars.

Marine larvae are three types. At some kinds of eggs, a free-laying larva hatching, which feeds microscopic algae, and then attached to the bottom and gradually turns into a small star. The other free-peeling larva has large yolk stocks, so it does not eat and immediately turns into an adult form. Nautical stars living in cold waters, the larvae are not separated at all from the body of the mother, and they accumulate near her oral hole or even in special gastric pockets. A caring female during this period relies only on the tips of the rays, and the body fuses the dome under which there are larvae. Since the larvae is located next to the mouth of the hole, the female during this period does not eat. The larval form is the most mobile in the life cycle of marine stars, it is during this period that the larvae can be distributed by trends to very long distances.

The larva of the starfish has a bilateral symmetry.

In addition to sexual reproduction, starfishes can multiply and useless. Most often this happens in multipath species, the body of the animal is divided into two halves, each of which increases the missing rays. In other species, the useless reproduction may be the result of regeneration during traumatic body damage. If the starfish is artificially divided into several parts, then from each new organism will be formed. For restoration, even one beam is quite enough, but it is necessarily necessary a piece of the central disk. Sea stars grow slowly, so in long months they look at one-sided.

The seagull caught a starfisher.

But the starfish of AstroCten is friends with multi-minded worms. One star can find up to five roommates who prefer to stay on the underside of the body closer to the mouth of the star. The worms pick up the remnants of the stars and even ... stick their heads in her stomach. At the marine star, Echinaster lives special species swallows that purify the surface of the star from the drawings.

These bright stains on the starfish Luzonicus (Echinaster Luzonicus) - Grebneviki (Coeloplana Astericola).

People from a long time drew attention to colorful animals of shallow water, but the starfish did not imagine any economic interest for them. Only in China is sometimes used in food, at the same time attempts to feed the marine stars with pets can lead to the death of the latter. It is likely that it is associated with toxins that accumulate some types of corals and poisonous mollusks. But with the development of the maritime, people began to rank marine stars to their enemies. It turned out that starfishes often pulled a bait in bottom traps for crabs, and also make raids on plantations for the dilution of oysters and marine scallops. For several years (it is so much to grow oysters) Sea stars can destroy the entire oyster jar. At one time of the sea stars tried to destroy, binding them into pieces, but it only increased their number, because from each chopping a new starfish grew. Then marine stars have learned to extract special trawls, and kill boiling water.

Very spectacular mosaic starfish (Iconaster Longimanus).

The most malicious pest was the starfish of the Akantster, or a thorns crown. It is a very large starfish eating exclusively by corals, after the thorns of the crown leaves only a white lifeless path on a coral reef. At one time, these stars have multiplied so much that in the literal sense of the word destroyed a huge plot of a large barrier reef off the coast of Australia. A unique geological formation was under threat of destruction. The struggle against the ternan crown complicated that its spikes of poisonous for a person, the injection crown hurts burning pain, although not fatal. Specially trained divers were collected by sharp peaks of the Akntasters in bags or was injected into the body of the sea star deadly dose of formalin. Only in this way it was possible to pacify the invasion of voracious predators and save reef. Now all types of marine stars are in a prosperous state and do not need protection.

The crown eats the coral.

Call a lot of questions, among which are of particular interest as the following: "What does the starfish eat?", "For whom it is a deadly threat?".

Stars on the seabed

These unusual seabed decorations exist on the planet for a long time. They appeared about 450 million years ago. Mix up to 1600 species of stars. These animals inhabit almost all the seas and oceans of the Earth whose water is quite salted. Stars do not tolerate desalinated water, do not meet them in the Azov and Caspian seas.

Rays in animals can be from 4 to 50, sizes range from several centimeters to a meter. Life life is about 20 years.

Nautical residents have no brain, but there is an eye on every rauma. The organs of view resemble insects or crustaceans, well distinguish light and shadow. Many eyes helps animals to successfully hunt.

Stars breathe almost through the skin, so a sufficient amount of oxygen is very important to them. Although some species can dwell on the decent depths of the ocean.

Features of the structure

I wonder how the starfish is breeding. Biology refers them to the class of invertebrates. The starfish has no blood as such. Instead of her, the heart of the star pumps over sea water vessels enriched with some microelements. Pumping water not only satures animal cells, but also with the help of fluid injection in one or another, it helps the star to move.

Sea stars have a radiation scheme of the skeleton structure - rays depart from the central part. Skeleton of sea beauties unusual. It consists of calcite and develops inside a small asterisk from almost several lime cells. What and how the starfishes eat, largely depends on the characteristics of their structure.

These players have special pedilation in the form of tweezers on their tentacles on each tip of the growing. With their help, the star hunt and brush their skins from the Sora's scoring between needles.

Cunning hunters

Many are interested in how naval stars eat. Briefly about the structure of their digestive system can be found just below. These amazing beauties create an impression of perfect security. In fact, they are sea predators, voracious and insatiable. The only drawback is slowness. Therefore, preferred delicacy - mollusc shells. With pleasure, the starfish feeds on the scallop, not to eat the sea hedgehog, the trepang and even carelessly flooded the fish.

The fact is that the starfish has almost two stomach, one of which can be turned out. The careless victim, captured by the pedilations, is transmitted to the river hole in the center of the rays, then the stomach is thrown onto it, like a cuckoo. After that, the hunter can release prey and slowly digest her. For some time, the fish even tested her executioner, but the victim is no longer escaped. All that the starfish eats is easily digested in its stomach.

It goes somewhat differently with the sinks: slowly comes to the dish like the dish, the shell swells with its rays, places the oral hole opposite the sink slot and begins to push the sash.

At least a small gap appear to appear, the outer stomach is immediately pushed into it. Now the sea farm calmly digested the owner of the sink, turning the mollusk in the jelly-like substance. Such a fate lies anyone eaten sacrifice, whether the starfish does not fit or shallow fish.

Features of the structure of the digestive system

The predator has any devices for capturing production. Roth surrounded by ring lip, connected with the stomach. This body takes the entire inside of the disk and has high flexibility. It is enough slit 0.1 mm to penetrate the sink sash. In the center of the aboral side, a narrow short intestine comes from the stomach. What the starfish is powered is largely depends on the unusual structure of the digestive system.

Love stars at the bottom of the ocean

Most marine stars are diverse. At the time of love games, individuals are so busy with each other, which stop hunting and forced to fast. But this is not fatal, because in one of the stomachs, these cutes seek in advance to postpone the nutrients for all the time of mating.

Sex glands are near the stars near the base of the rays. When pairing women's and male individuals connect rays, as if merging in gentle embrace. Most often, caviar and men's sexes fall into sea water, where fertilization occurs.

In the event of a lack of certain individuals, the stars can change the floor to maintain a population on a certain territory.

The caviar of these most often remains granted itself until the larvae hatching. But some stars turn out to be caring parents: they wear caviar on the back, and then larvae. For certain types of marine stars for this, there are special bags for caviar, well-washed with water during the pairing on the back. There it can be under the parent until the appearance of larvae.

Reproduction of division

A completely extraordinary ability of marine stars - reproduction by the method of division. The ability to grow a new hand-beam exists practically in all animals of this species. A star captured by the predator for the beam may discard him like a lizard tail. And after a while to repel the new one.

Moreover, if a small particle of the central part remains on the beam, from it after a certain time a full-fledged starfish will grow. Therefore, it is impossible to destroy these predators to destroy these predators.

Who are afraid of starfish

The enemies of the representatives of this class are a bit. No one wants to communicate with poisonous needles of marine innovatives. Animals are still able to distinguish odorous substances to scare away especially voracious predators. In case of danger, the star can go into IL or the sand, having done almost invisible.

Among those who feed on the sea stars in nature, sea large birds prevail. On the shores of the warm seas, they become prey of chaps. In the Pacific Star, the star is not averse to enjoy fun kalans.

Predatory harm underwater plantations oysters and scallops - what a starfish is supplied. Attempts to kill animals, bringing them into parts, led to an increase in the population. Then they began to fight with them, putting stars ashore and welded in boiling water. But it was nowhere to use these remains. There were attempts to make fertilizer from animals, simultaneously scaring pests. But widespread and this method did not receive.

ASteroidea class name ( sea \u200b\u200bstars) Comes from the form of the body united in this class representatives of igloski, having a view of the star, most often a five-pointed, or flat right pentagon.

Among the animals who lived to the present day, starfish is one of the most ancient groups. In the fossil state, they are known from the Nizhny Paleozoic - from the Ordaic period, which is estimated from our time about 400 million years.

In the seas with the normal salinity of various marine stars can always be seen at the very shore - on the littoral, that is, in the zone poured water during the tide and exposed when they are low. Therefore, starfishes were well known to a person already in ancient times. Their images were found on the frescoes of 4000-year old, found during the excavations on the island of Crete. The very name of ASTER, that is, the star was given by this amazing animals by the ancient Greeks. Aristotle more than 2 thousand years ago included marine stars in the classification of animals created by it, and he knew that "they, attacking, suck many sinks."

Sea star class Includes two detachments - Platyasterida and Hemizonida, fully extinct in Paleozoa and studied only on finding their skeletal residues, and three detachments, numerous representatives of which exist and now:

1) Phanerosonia (from the Greek Words of Phaneros - a clear and zone-belt), or annealing stars who received their name from well-visible outside of the rows of lime plates, bordering the edges of the star;

2) Spinulosa (from Latin Spinula - a small needle, spike), or needle stars, and

3) Forcipulata (from the modified Latin Forceps - tongs), or pedaceous stars, i.e., stars, in which there are always numerous skeletal appendages on the body in the form of a crumbling-pedalized pedilation.

With the general same type of the structure of all marine stars, they are very diverse as on the external form, sizes, color and nature of lime skeletal formations (plates, needles, spikes, pedies), from which the external appearance of the animal, and in their way of life and The conditions in which they live. More than 1,500 modern species of marine stars belonging to about 300 genera and 29 families are known.

Sea stars are typical inhabitants of the oceans and seas, the water of which is inherent in the normal ocean salinity (about 35 ° / 00). None of the representatives of marine stars failed to adapt to life in fresh waters. In the highly desalinated seas of the star or absent, as, for example, in the Azov and Caspian seas, only single species presented in these conditions are obviously oppressed. For example, the adults of the Asterias Rubens star are penetrated into the western part of the Baltic Sea to areas with salinity of 8 ° / 00 (at the island of Rügen), but apparently cannot multiply with such strong desalination, and the population of this star is supported here The expense of the brings ready to settle the larvae from more solenic areas. And the only star penetrated from the Mediterranean Sea to Black (Marthasterias Glacialis), lives only in his most calendous southwestern corner near the Bosphorus Strait and could not smalle the rest of the sea. Such solenitivity of marine stars is associated with the fact that they all relate to the porosmotic animals, i.e., to such that they are not able to regulate the overall concentration of salts in liquids that fill the body cavity. Therefore, the concentration of salts in the stripe fluids, wash all the fabrics and internal organs of stars, is entirely depends on the salinity of the surrounding water, and strong desalination turns out to be destructive for these typical marine animals.

Under favorable conditions, some types of marine stars can multiply in very large quantities and form a large density population. In the oceans and the polish seas, starfishes are common everywhere, from the Northern Ocean and Waters, washing the coast of Antarctica, to the tropical and equatorial zones of the ocean. They are abundant and on the littorals of our northern seas, where they withstand sharp seasonal fluctuations in temperature, and in winter they can even freeze, and on constantly heated tropical shallow water, where numerous species live among the lush thickets of rhyme-forming corals. As the depth increments increase, the diversity of marine stars is highly decreasing, but also at the bottom of the ocean bed with its constant homogeneous conditions - a complete lack of light, low temperature and huge pressure - they are found everywhere, and representatives of three families (Porcellanasteridae, Pteasteridae and Brisingidae), one by one From each detachment, penetrate the depths of more than 6 km. With the works of the Soviet Expeditionary Ship "Vityaz" in the Pacific Ocean, two types of stars from childbirth Porcellanaster and Hymenaster were found in the northern part of Mariana deep-water gutter at a depth of 7600 m, which, apparently, is the limit of marine stars into the depths of the ocean.

All starfish in adulthood lead a bottom lifestyle, crawling on the bottom surface or instantly in the sand or silt. Many stars, especially from among those living in shallow water, are active predators that feed on various molluscs, crustaceans, intestinal and other invertebrates, including iglozzy. Along with this, the deep-sea stars are very common and iloshedral forms, swallowing the soil in which they live, and using organic remnants contained in it.

Apparently, starfishes were very numerous in the seas of past geological eras, but entire, well-preserved specimens are found in fossil state quite rarely. Lime plates of marine stars do not form a single durable skeleton, and fasten with each other with a connecting cloth and muscles. Therefore, only scattered plates or stars are found in the fossil condition.

The most ancient and primitive stars from the Somasteroidea group were described in 1951 by V. Spencer (W. Spencer) from Nizhneorkovik sediments of southern France. And a few years ago, a modern star of Platasterias Latiiradiata, who lives in the shallow water of the Pacific coast of America in South Mexico and Nicaragua, was assigned to the newly waved zoologist B. F. Spencer and Fell view the Somasteroidea group as strengthened Square Class (STELLEROIDEA), to which they are as two other subclasses include real marine stars and official. However, here we are considering marine stars and officials as separate classes in accordance with the classification, generally accepted in modern manuals.

Sea stars usually have a more or less flattened body with a central disk, gradually turning into the radially divergers from it rays, or hands (Fig. 138). The head of the star with the mouth of the hole in the center is called oral, i.e. the mouth, and the upper side - the aboral. Sometimes the oral side is conventionally called the abdominal, and the aboral - dorsal. In stars that have an anal hole, it is located near the center of the aboral side of the disk. In the middle of the lower side of each beam passes the furrow, in which there are numerous soft moving outgrowths - ambulapral legs that serve as a star for movement.

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Typical for marine stars is a five-way structure, but rather numerous species have six or more rays. At the antarctic waters of stars from the genus Labidiaaster, the number of rays can reach 45, and the Heliaster's sunny star even 50. Sometimes the number of rays is different from different individuals of one species. So, in our northern and Far Eastern seas of the star Crossaster Papposus, the number of rays ranges from 8 to 16. In some cases, the number of rays from stars of the same species may vary depending on the habitat, in others it can increase as the stars grow . The ratio of the size of the rays and disk is also very different. To characterize the shape of the bodies of marine stars, the ratio of the radius length (R) is usually used, that is, the distance from the center of the disk to the end of one of the rays, and interradius (g) - the distance from the center of the disc to its edge in the interval between the rays. Most often, the length of the rays is 3-5 times higher than the disk radius. At the most long-headed stars, for example, some deep-water BrisingIDae with a very small disk and numerous very thin and fragile rays, R can be 20-30 times higher than g, and many stars from the Phanerozonia squad and some spinulosa rays can only get out of the edges A wide disk and the body has the form of the correct pentagon, in some cases so flattened that the star is similar to flat cookies, in others - more or less convex. Even stars are known, the appearance of which is so changed that at first glance they are difficult to recognize for marine stars. In the usual inhabitant of coral reefs Culcita (Table 19), a very bloody body resembles almost a round pillow or a bunch. However, this body shape developed secondary and characteristic only for adult individuals, and very young coccytes look like ordinary pentagonal asterisks. The recently described view of Podospharaaster Polyplax (Fig. 139) has been changed even stronger. The only copy of this unusual spokesman for marine stars was found at a depth of about 80 m in the South China Sea. The podoxister has a form of a ball with a diameter a little more centimeter and looks more like a marine hedgehog than a star. However, five ambulapral grooves pass from him only on the lower hemisphere corresponding to the oral side of other stars, while maritime bands of the plates with ambulacral legs are moving on the upper half of the body. The nearest relatives of this star, who, together with it, the SPHAERASTERIDAE family are known only in the fossil state from the deposits of Jurassic and chalk. The sizes of marine stars are very different. In the smallest types of diameter, or, more precisely, the greatest distance between the ends of the opposite directional rays does not exceed 1-1, 5 cm, while the largest individuals of some species - Acanthaster and Pycnopodia (Table 19 and 25) - it can reach 50 and even 80 cm, and brisingid (Freyella Remex) The length of each of its ten hands is 45 cm.

Many stars are mainly in the species living on the littoral and at small depths, the upper side of the body is often painted in very bright colors, while the bottom usually has a pale yellowish color. In the color of the aboral side, a variety of shades of orange, pink and red colors are dominated, but stars painted in purple, blue, green, brown and even black color. Sometimes the color is spotted and various bright colors can form a quaint drawing. Stars, inhabiting the depths of the ocean, are sometimes painted in a reddish tone, but more often deprived of bright pigmentation and look yellowish or dirty gray. Coloring stars depends on pigment inclusions in the cells of the skin epithelium.

At the first sight on the starfish, first of all, the elements of a lime skeleton are noted on the surface of the body - the needle plates, small spikes, hillocks, etc. However, in reality, the skeleton of marine stars in its origin is not external, as, for example, in mollusks or arthropods, and the internal, formed in the connecting layer of the body walls. All noticeable outside of the skeleton is dressed with a coating epithelium and a thin layer of connective tissue, but adult animals have these covers on the most protruding parts, exposing the skeletal basis.

The main support skeleton of stars (Fig. 140) consists of numerous separate lime plates interconnected by connecting tissue and muscles. The skeleton of the oral side is stronger. Along the entire lower side of each beam, there are two rows of ambulatary plates, having a kind of lying across the beam of oblong shelter. Slopedly located opposite plates of each row are connected by its upper ends, forming a roof going along the ray of an ambulatary furrow. These plates on each side of the furrow adjoins a longitudinal range of adambulacular plates, followed by two rows of edge (trunk) plates forming the side edges of the rays and disk. For some stars, the edge plates are large, well visible outside (Phanerozonia), others are poorly developed and are not much different from skeletal plates of the top side of the star. For most stars, additional rows of plates are developed in one way or another, especially in the interradial spaces of the bottom of the disk. The skeleton of the upper side of the body in different stars is developed in very varying degrees. Most often, it forms an incorrect network from numerous plates in contact with its ends (Fig. 141, b).

In one of the interradius of the upper side of the disk, usually near its edge, there is a special madpore plate, the pierced surface of which is permeated with small pores. Through the Madeporovy plate, a connection of the ambulact system with an external environment is communicated.

In addition to the support skeleton, marine stars have a variety of and numerous skeletal appendages, most often in the form of needles or spikes having a protective value. Usually, they are movably molded with plates of the main skeleton. Plans can be simple and in the form of Paxilla, which are lime columns, crowned on top of a group of small spines or needles (Fig. 142, 1-4), Some Paxillars are sitting on a spinal surface so It is closely that their sizes form solid cover. Part of the needle is modified in various shapes of small forceps - pedies (Fig. 141, l and 142, 5-4), sitting directly on the plates of the main skeleton or on the needle or rising above them on flexible stalks. Movable and very numerous pedies cleans the body surface from contamination, grasping and discarding foreign particles entering it. Along with this, they can also perform a protective function.

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In the intervals between skeletal plates of the dorsal side, and some stars and in the oral side, there are numerous gentle thin-walled outgrowths in which the body cavity comes, - papulas, or skin gills that serve mainly for breathing (Fig. 141, a). To a large extent, breathing occurs through the walls of the ambulatal legs, and sometimes through other parts of the body surface. Stars are moving using numerous ambulapral legs, pairwise extending from the radial channels of the ambulact system stretching to the end of each beam (Fig. 123). Through the intervals between the ambulact plates of the skeleton, the legs go out into the ambulatary furrow. The legs are mostly two, and some stars are four rows along the entire length of the beam. The total number of them in each of the rays can reach several hundred. Each leg is connected to an ampoule inside the beam - a muscular bag in the form of a small bubble capable of shrinking and stretched. The legs themselves can also be very pulled out and shrink, as well as bend in any direction. For most stars, the legs are equipped with suction cups. One leg sucking to any surface, shrunk, can develop an effort to 30 g, and with a joint coordinated action of numerous legs of several rays, the strength of the thrust developed by the star can reach several kilograms. This turns out to be more than enough even for the movement of the star up the vertical plane, as well as to hold rather large production and for opening tightly closed shells of bivalve mollusks. It is curious that the clutch force of the sucker legs with the substrate exceeds atmospheric pressure and more than 40% of this force is due not to the requisitive effect of the vacuum suction cup, and the adhesive mucus constantly released by the glands of the sucker epithelium. The ambulatary legs are equipped only with a longitudinal muscles providing their abbreviation, and their stretching is caused by hydrostatic pressure of the liquid, injected into the legs of the compressed ampoules.

Musculature from maritime stars is developed relatively weakly. Muscular litter passing along the dorsal side of each beam serves to bending the beam up. The muscle system connecting the skeletal plates of the oral side provides the narrowing and expansion of the ambulatary furrow and the lateral bending of the rays. The muscular fibers are equipped with outdoor skeletal appendages, ambulatal legs, skin gills. The BenthopectiniDae deep-sea star (Phanerozonia), for which long and flexible rays are characterized, differ from all other stars with paired muscular heavys passing around each beam along its spinal surface. Apparently, the stars of this family are capable of making movements with such muscles, allowing them to emerge and swim short distances near the bottom.

Although most stars are active predators, any devices for breaking production and for chewing foods they do not have. Specialized roth plates of the skeleton are adapted only for pushing food in the mouth. Surrounded by soft leathery - peristol, the mouth is able to stretch wide. With a short esophagus, it is connected to the bulk stomach that fills most of the internal disk space. A short and narrow rendering from the top of the stomach opens on the spinal side near the disk center with anal hole. However, the latter is so small that it practically cannot serve to remove undigested food residues, and they are thrown out through the mouth. In the upper part of the stomach from it in each ray, paired branchy blinds are deployed, so-called pyloric, or hepatic, appendages, to the internal channels of which digestive juices are highlighted. In the walls of hepatic appendages, absorption of digested food and the reserves of nutrients are accumulated, which can be spent in cases where the star is not powered for a long time, for example, in the period before reproduction or when it is tooling with soils. Fasting for 6-8 weeks leads to full expenditure of such reserves.

In some stars, the render, anal hole and radial gastric grows are missing and the entire digestive tract consists only of bag-shaped stomach. Such stars usually belong to Iloid forms.

Many stars possessing long and flexible hands, mainly from the Asteriidae family, are able to turn outward the stomach (its lower part), envelop their victim and digest her, not swallowing. The stomachs of such stars never find residues of food. Other stars with short or with insufficiently flexible hands are not able to hold for a long time. They swallow sometimes quite large animals and after digesting their soft parts ejected outward remnants, such as molluscs or shell shells or shells.

The food spectrum of many large predatory stars is very wide. Although they usually prefer to eat those or other specific animal species, but often eat many others or their corpses. But some stars food is strictly selective. Some of them eat only sponges, others feed on coral polyps, and food Coscinasterias Calamaria constitutes mainly brachiopods whose shells this star opens the same way as other stars open bivalve mollusks.

The nervous system of marine stars is very primitive. They have no clearly pronounced brain ganglia.

Despite the primitiveness of the nervous system of marine stars, conducted by a number of researchers, experiments were shown that conventional reflexes can be produced. In the usual on the littoral of Murmansk star Asterias Rubens, a multiple combination of food with a certain surface of the substrate, according to which the star crashes, managed to develop a selective reaction to this type of surface. The stars of the same species, tangled in the grid, gradually "learned" to be released from it much faster than at the first experiments. Developed conventional reflexes can be maintained without reinforcement up to five days.

From the morphologically separate organs of feelings of the stars only eyes are developed. The last unpaired outlacral leg of each beam is deprived of the sucker and is a short tentacle, at the base of which there is a red eye, consisting of numerous separate eye beds. With the help of his eyes, the star cannot "see" in his own sense of the word, but can only distinguish the intensity of lighting and the direction of light.

In addition to the unpaired terminal tentacle, several ambulapral leg neighboring with him also do not have suckers and perform the touch function. The crawling star always pulls them forward and feel the surface of the substrate. In the epidermis of the walls of the body of the stars everywhere there are sensitive nervous cells. They are especially numerous in the suction cups of the outlaccral legs, at the bases of needles and pedies and on the sides of the ambulapral furrow. In such sections, their number can reach 70 thousand on the area in 1 mm2. Apparently, act as the tanging authorities can not only end tentacles, but also suckers of the rest of the legs. In addition, the accumulation of nerve cells can perceive taste and other chemical irritations. Stars of some species react to food, on the distance walking from them up to half a meter. Even a case is described when the star Asterias Vulgaris has moved directly towards the food, which was from it at a distance of 12 m. Fishermen, putting traps on large sea crayfish LANGOST, it is well known that the stars often slide to traps and accumulate in them By walking the bait designed for Langust. However, sometimes chemorezing is practically absent. In some cases, the hungry stars were crawling out in several centimeters from their favorite food, not noticing her, and eat food only when they accidentally came down at her.

There are no special excretory bodies. Removal from the body of finite metabolism products is mainly movable amoeboid cells, numerous in liquid filling body cavity. Amoeboid cells loaded with products move to the body surface and are chosen outward mainly through thin-walled skin gills. In addition, the final exchange products are allocated by special secretory cells into the channels of hepatic appendages, where they get into the stomach and are removed outward.

Most sea stars separatogs. But there are often cases and hermaphroditism in various manifestations. For example, Marthasterias Glacialis, along with the individuals of one or another floor, there are stars with mosaic hermaphroditic gonads. And the usual Atlantic coasts of Europe Asterina Gibbosa in populations of certain areas prevails the so-called protendry hermaphroditism, when young stars function only as males, and growing up to certain sizes - just like females. But in other areas, the stars of the same species can be males, females or hermaphrodites regardless of size.

In typical cases in each beam near its foundations there are paired sex glands, which are opening out between the rays or sometimes on the oral sides of the body. But in a number of species, numerous gonads are located inside the rays serially and open out each of their own hole.

In appearance, male and female individuals are usually indistinguishable, except in cases where females show care for offspring and enter the developing young people. But sometimes the stars of different sex may differ slightly in size or in color during the reproduction period. In the already mentioned Asterina Gibbosa, the males during the reproduction period accumulate around the female and press it to her rays so that the released sperm gets straight on the eggs sweeping into the water. And shallow-water tropical Archaster during reproduction even unite in pairs.

The embryonic development of stars may proceed with the stage of free-peer larvae, from which a young star is formed as a result of metamorphosis, or be direct. In most stars, sex cells are available directly into the water, where the egg fertilization occurs and their further development in the bilateral symmetric bipinarium larva (Fig. 143, L-D). Such symmetry of the larva-trace of the origin of marine stars from the distant ancestors of all modern oskalkin, also had bilateral, and not radial symmetry. After a few weeks of life in the thickness of the water, during which the larva is actively powered by microscopic algae, three growers are formed at the front end of the bipinnarium and it turns into the larch of the next stage - bracholarium (Fig. 143, e-). Bracholaria soon settles on the bottom, attached by the suction cup located between the growth of the front end and undergoes the metamorphosis, in which the role of the stalk front of the bracholaria is degenerating, and a young asterisk is formed from the rear part containing the stomach.

With direct development, relatively few large and yolk eggs are developing without a stage of free-pointed larvae. Many stars with such a type of development in one way or another show care of the offspring. In Asterina Gibbosa and some other stars, this concern is limited by the fact that they attach eggs to various underwater objects, most often to hanging over the bottom surface of the stones, and then crawl. However, most inhabitants of cold waters of polar regions or large depths developing engines and even formed young stars are launched on the mother's body until they become capable of conducting an independent existence. In particular, all the stars inhabiting the Antarctic region, no matter what detachment they belong to which detachment.

In stars from Spinulosa and Forcipulata and Forcipulata, with more or less long and flexible rays, having tolerance of the Most often occurs as follows. The mother's individual relies at the bottom of the rays, and their bases and the disc bends so that they form the semblance of the bell, inside of which the mouth is located. In the cavity of this bell and the developing sprockets are placed, connected by general gravity to which each of them is attached to its oral part. During the entire time of tooling its offspring, the mother does not eat. Living in the cold waters of the Arctic of a small star Leptasterias Groenlandica young develops inside the stomach of the mother - in the special silent growths of its front.

Stars with short wide rays and less flexible body are not capable of forming a brood chamber under the oral part of the disc, and the development of juveniles may occur on the spinal side of the body, or directly on its surface between Paxillas (some representatives of Phanerozonia), or in a special brood cell ( PTERASTERIDAE Family from Spinulosa). A more detailed description of these stars will be given below.

The fecundity of stars whose development flows into the thickness of water can be extremely large. According to the estimates of the English researcher, Gemmill (J. Gemmill), Asterias Rubens only released about 2, 5 million eggs to the water, and during the reproduction season, the ease of eggs can occur several times. The well-known specialist in Iglinodi Dane T. Mortensen (T. Mortensen) found that another star is even more prolitis - Luidia Ciliaris, in the ovaries of which can be up to 200 million eggs. The fecundity of stars who carry their offspring is incomparably less. At stars who wear young on the underside of the body near the mouth, developing germs usually no more than 200, although sometimes their number can reach 1000. And the number of young stars developing on the back or in special brood chambers does not exceed several dozen.

In some stars, along with sex, the useless reproduction can occur by dividing the disk into two parts. The division line usually passes in a certain direction through interradius, so that the rays of each part that formed as a result of division remains intact. Both parts of the star begin to exist independently, and they restore the missing rays and sections of the disk. This type of division occurs in a number of species of the Asteriidae family (Forcipulata), usually among those who have more than five rays, as well as some representatives of the Asterinidae family from Spinulosa's squad, for example, in the tropical waters of the Australia of stars from the gennthia genus (Fig. 144, B). Only young stars can multiply in the city, other ability to decline remains throughout life. Stars breeding in this way, rarely manage to find with rays of the same length: growing up to the rays of one of the half of the body significantly smaller than the rays of the other half, which went to the inheritance star from the maternal individual. All species of the genus Linckia (Phanerozonia), the useless reproduction occurs in another way (Fig. 144, L), which we will tell when describing these stars.

With the ability to reproduce by division, a very developed ability to regenerate is connected, that is, to restore body parts, lost due to injury. Some stars can restore all the missing parts, even after cutting them into several pieces, but usually only in cases where such a piece consists of at least one ray and adjacent to it. And Linckia, the whole star can grow even from part of the beam. There are cases when the stars can with danger spontaneously discard rays, and then grow them again. If the end of the ray turns out to be injured in the longitudinal direction, each part may continue to grow independently and is formed a peculiar ray, split at the end in the form of a fork. Interestingly, the star, deprived of the whole hand, regeneration takes place at a greater speed than with a loss of only the tip of the beam. Young stars have lost parts usually restore faster than older, and heat-water tropical species are faster than in the inhabitants of cold-water areas.

And what do you know about starfish? Beautiful and unusual creatures, with many interesting facts from their life - about two thousand seeding species are currently known in our selection.

Nautical stars have no brain and blood - to produce nutrients, oxygen and other important liquids, the starfish pumps through its body. It is the resulting water that is distributed through the body and forms a "water-vascular system".

On each hand of a starfish, mistakenly taken for the tentacles, there are about 15 thousand tiny suckers, thanks to which the starfish moves.

The starfish is not a fish, but an invertebrate animal.
Sea stars are real predators. They are able to attack themselves like and can easily enjoy a small offspring of their varieties, i.e. are cannibals.

The stars have two stomach, one of which they can even push out to digest mollusks.

Starfish - long-livers, some species live up to 30-35 years.

Many of the marine stars are very dangerous. For example, the sea star of the throat crown, common in the Indo-Pacific-Ocean, is covered with poisonous spine. Growing almost half meters long, these creatures become dangerous not only for coral reefs, but also for divers and swimmers.

Sea stars are able to easily change the floor, after which it is possible to switch back. True for such "transformations" needs several suitable conditions for water quality, temperature and food availability.

Sea stars have eyes - exactly as many as the rays, the eye is located on the conchor, look like a red spot. They see, of course, not very good, but at least distinguish the darkness and light.

Despite the fact that starfish live under water, they have no gills.

Although the type of majority of marine stars corresponds to their name, sometimes there are unusual individuals of the bizarre form. For example, starfishes may have a sun shape, numerous rays or their form can be rounded.

The heart of starfish beats with a frequency of 5-7 blows per minute.

The largest starfishes can reach 1 meter in diameter, and their weight can reach 5 kilograms. Solar stars are more active than their kinds, and are able to rapidly pursue their prey, and, having an incredible force, simply tear the shell of mollusks and crustaceans.

Feeding method allowing the starfire to eat prey, much more than the oral hole is as follows - as the mouth of the starfish is on the bottom side of her body, the star, grasping the prey wraps his strong hands around her, and then a strong jolts puts under him, and then Then pushes into the stomach.

It is also one of the most ancient residents of the Earth. Starfish about 250 million years.

Stars are moving with hundreds of pipes, which are attached to the surface, and then wave moving.

Sea stars live in a wide variety depths, up to ten kilometers

In the past few years, starfish has become actively multiplied. This creates a problem, because each individual has an excessive appetite and consumes about 6 square meters of corals per year. In some areas, measures are used to destroy stars.

However, starfishes nevertheless bring much more useful than harmful - this is important consumers of carbon dioxide - annually starfish in aggregate destroys about 2% of the carbon diquses of the Earth, and this is an extremely large figure as part of a whole planet.

Another useful role of marine stars is to clean the seabed from fell, weak and sick beings of the seabed, as well as from the remains of the dead oceanic organisms.

Sea stars pass five stages of growth before becoming adults - during the first month, the stars swim freely and look like jellyfish, they are small, almost imperceptible to the eye and tiny plants and animals of the ocean.

Although most naval stars are not poisonous, a major star called Akantster or a crown is dangerous for a person. The injections of her needles bring a burning pain to a person - if the needle is stuck in the skin, then it is clogged from the body of the star and begins to infect the blood of a person to poisonous secretions.

An interesting fact - if you cut off one of the hands of the starfish or immediately everything, without damaging the central part of the body, then they will gradually grow again.