Starfish are echinoderms of the family Avenidae,[7-9]It is also known as sea wheel and starfish.[10]Flat, star shaped, with hollow wrists.[11]Bright colors.[12]Most adults are five radially symmetrical (with five wrists);The mouth is located in the middle of the lower side of the base and forms the oral surface together with the wrist abdomen;The middle of each wrist has a step band groove, from which small tubular appendages, called tube feet, protrude;There are calcareous bone slices and muscle layers under the epidermis, which can make the wrists and feet move.[13]It is generally dioecious, and some are hermaphroditic.[11]The service life can reach 35 years.[14]
Starfish are distributed in various sea areas of the world, among which the North Pacific is the most widely distributed.[15]It can also be seen along the coast of the Bohai Sea and the Yellow Sea.[16]They like to live in groups and often inhabit the seabed with sand, rocks or corals.[15]It is rare in soft mud bottom.[11]Carnivores,[17]Their food sources are mainly shellfish, sea urchins, crabs, sea anemones and other slow moving marine organisms, and even beautiful and colorful corals.[18]It has strong reproductive capacity,[12]It usually breeds offspring in summer, and eggs and sperm are fertilized in seawater,[14]Form a new life.Most starfish do not reproduce asexually.[12]
In terms of medical value, the ingredients contained in starfish have good effects on hyperlipidemia and cardiovascular and cerebrovascular diseases.The starfish body can also extract gelatin for making capsules.[19]In terms of ecological value, it plays an important role in maintaining ecological balance.In terms of economic value, it has high nutritional value and is rich in fat and protein.In the production field, it can be used for composting.In industry, it is often used to process into powder feed.[20]
Starfish andsea cucumber、Sea urchinEquivalency genusEchinoderma。They usually have five wrists, but there are also four or six. They are flat and mostly star shaped.The whole body is composed of many calcareous bone plates combined by connective tissue, and there are prominent spines, tumors, warts and other appendages on the body surface.Some have as many as 50 wrists, and there are four rows of dense tube feet on the lower side of these wrists.Tube feet can not only catch prey, but also allow themselves to climb rocks. Large starfish have thousands of tube feet.The mouth of a starfish is in the middle of the lower side of its body, which can directly contact the surface of the object that the starfish crawls over.The size of starfish varies from 2.5 cm to 90 cm, and the body color is also different. Almost every starfish is different, with the most colors being orange, red, purple, yellow and cyan.[1]
The body diameter of starfish is generally about 12-24 cm, but the size varies greatly from species to species, and the diameter varies from 1 to 80 cm.Most of the body surface is yellowish brown, but some species have bright red, orange, blue, purple or a mixture of several colors.The body has five stars, such asSea pan car, extend five wrists outward from the central plate.Sun and Sea StarYou can have up to 40 wrists.Most types of wrists are wider near the central disc, and their ends are thinner, while a few are similar.The length of the wrist is generally 1-3 times the diameter of the central disc, but some wrists reach 4-5 times.[2]
Some species have short wrists to make their bodies pentagonal, such as Culcita.The central area from the wrist to the central disc is called the bulacral area, also known as the radiation area.The part between the step zones is called interla bulacral area, also called interladii.In life, on the downward side of the disc car, there is an opening in the center of the central disc, and the opening is membranousCircumoral regionThis side is called mouth side.The opposite side, the upper surface, is called the counter face.A wide groove extending from the mouth to the end of each wrist is called stepping groove. There are 2-4 rows in the grooveTubular foot。There are movable long spines on both sides of the step belt groove, which can be closed and protected at any time.There is a small cluster of tentacles at the end of the wrist, and a red eyespot under the tentacle at the end.The central part of the central disc of the contraoral surface has an anus, but it is generally difficult to see.There is a small round plate, called sieve plate, between some two wrists near the edge of the central plate, which is the gateway between the water pipe system and the outside world.Because many thorns and spines protrude outward from the body surface, the whole body surface, especially the anti oral surface, is usually very rough.The spines and spines on the body surface of some species are flat, which makes the body surface slightly smooth.The positions of the oral and anti oral surfaces are not identical in all classes of echinoderms.Due to the change of lifestyle, the mouth may face upward (crinoids), or the difference between the mouth and the counter mouth may not be obvious (Holothurians).[2]
The body wall of echinoderms consists of epidermis and dermis.The surface of the body wall is a very thin cuticle, with a single ciliated columnar layer insideepithelial cells。The epithelial cells are mixed with neurosensory cells and mucous gland cells,Glandular cellThe secretion of can adhere to the sediment on the body surface and then be swept away by cilia.Below the epidermis is a layer of nerve cells and fiber layer, which forms the subepidermal nerve plexus of echinoderms.Then there is the dermis, including a thick layer of connective tissue and muscle layer.The muscles can be divided into the outer ring muscle and the inner longitudinal muscle. The longitudinal muscle on the reverse oral surface is developed, and contraction can bend the wrist.Within the muscle layer is a layer of body cavity membrane (perineum).[2]
EchinodermicbonesfromMesodermIt is an endoskeleton, located in the connective tissue of the body wall.It is a mesh bone formed by many separated small bone pieces of different shapes connected by connective tissue, and is composed of calcium salt mixed with 10% magnesium carbonate.The small bone pieces are perforated, which can reduce the weight and increase the strength.Each small bone slice is formed by a cell in the dermis first secreting a crystal, surrounding the crystal, and then by the surrounding cells secreting and accumulating calcium salts, so the bone slice can grow with the growth of animals.The size, shape and grid arrangement of bone slice depend on the structure and arrangement of dermal cells.[2]
In addition to bone fragments, there are also some spinesForked spineBone components such as pedi cellaria and paxilla are scattered on the body surface to defend and eliminate deposits on the body surface.Some of the fork spines have no handle, and some have handles.Fork spines are very common in the sea wheel and acanthoptera. They are composed of small bone plates in the form of pincers or scissors. They control opening and closing by means of a pair of antagonistic muscles at the base.Some fork spines are arranged in a circle around the spines.There are separated umbrella shaped bone pieces on the opposite side of the mouth of the starfish of Phaneroptera, and there are many movable spines on the umbrella, which is the spinous process bundle. It is suitable for living in caves in the sand.In addition to thorns and spines, there are a lot ofSkin gillIts structure and function will be described in the breath section.[2]
Body wall and skeleton of starfish
Water pipe system
Announce
edit
The water vascular system is a unique tubular system of echinoderms. It all comes from the body cavity, so the inner wall of the tube is wrapped with the body cavity epithelium and filled with liquid. Its main function is movement.The water pipe system is connected to the outside through the sieve plate.The sieve plate is a calcareous round plate, covered with a layer of ciliated epithelium, with many grooves on the surface, many holes and pipes at the bottom of the groove, and enters a capsule below, which is connected to the stone tube below.[2]
The stone tube is named for the calcareous deposit on the tube wall. The wall tube has a protrusion that extends into the tube cavity and separates the tube cavity incompletely, so as to allow the liquid in the tube to flow towards the mouth surface and the opposite mouth surface at the same time.The stone pipe is vertically downward from the counter face and connected with the circular canal around the mouth after reaching the mouth face.The circular water pipe is located on the inner surface of the mouth bone plate, and the pipe wall is often folded, which also divides the pipe cavity into many small pipes. Its role may be conducive to the flow of liquid in it.There are 4-5 pairs of folded cystic nodes called Tiedemann's bodies on the circular tube of the interspoke area, which may be used to produce coelomic cells.In addition, a considerable number of starfish have 1-5 sacs with tubes on the annular tube, called the Polyanvesicles. There are muscles on the wall of the sacs to store the liquid in the annular tube.There is no Polly's bursa in the scallops.[2]
A radial canal extends from the loop tube to each wrist to reach the end of the wrist. The radial canal is located outside the carpal bone plate in the walking band groove. The radial canal extends out of pairs of lateral canals on both sides along the way, alternating left and right.The end of the lateral canal expands, passes through the carpal bone slice and enters into the body cavity to form a pull.The end of the altar sac becomes the tube foot and enters the footband groove.[2]
Many kinds of tube feet have flat ends to form suction cups.The structure of the tube foot is similar to the body wall, with ciliated epithelium outside, cavity epithelium inside, and muscle and connective tissue in the middle. Muscle contraction controls the bending or extension of the tube foot.If the side water pipes extending from the radial water pipe to both sides are equal in length, the pipe feet show two lines in the step groove;If the length of the lateral water pipe is alternate, the pipe feet show 4 rows in the step belt ditch.Sea pan carIt shows four rows.The water pipe system is full of liquid, and its body fluid is isotonic with seawater, which contains coelom cells, a small amount of protein and very high potassium ions. It is equivalent to a hydraulic system in motion.When the altar sac contracts, the valve at the junction between it and the side tube closes, the liquid in the capsule enters the tube foot, the tube foot extends, and contacts the ground. The sucker at the end of the tube foot generates vacuum to attach to the ground.When the muscle of the tube foot contracts, the tube foot shortens and the liquid flows back to the altar sac.In this way, echinoderms rely on the coordinated contraction of the tube feet to complete the movement, while other parts of the water pipe system may only be used to maintain the pressure balance in the tube.[2]
Experiments have proved that the liquid in the tube does not exchange with the outside world.Starfish movement often takes 1-2 wrists as the leading wrists, and the tube feet in the wrists extend and retract in the same direction synchronously.But in fact, the tube feet of the five wrists do not always extend in the same direction or are completely coordinated, so the motion of starfish is very slow.When the body turns over accidentally, it uses 1-2 wrists to turn back to its normal position, and attaches to the ground. Then the body turns over from below the wrists to resume normal movement.The sea stars of banded order, such as AsteropectenSand starfishThey live on the soft seabed, their pipe feet have no suction cups, and they are arranged in two rows in the gait groove. These characteristics are conducive to their burrowing or crawling in the sediment.[2]
Water pipe system
Feeding mode
Announce
edit
Starfish are carnivorous animals, which can feed on various invertebrates, especially shellfish, crustaceans, polychaetes, and even fish.Some of them are monovorous, for example, many species usually only eat bivalves.There are also polyphagous or omnivorous species.[2]
There are basically three feeding modes:
one
Most starfish have long and bendable wrists and suction cups on the tube feet. They mostly feed on bivalves. When taking food, their body is on the shell and they suck on both sides of the shell with two wrists. Due to the vacuum effect of the suction cup at the end of the tube feet, the pull force is enough to open the shell mouth of bivalves. The starfish immediately turn out the cardiac stomach and insert it into the shell mouth, and secrete digestive enzymes until the adductor muscle and internal organs are partially digested,Fully open the shell, and then surround the stomach to swallow food and enter the mouth.
two
Some species with short wrists and tube feet without suction cups feed on smaller animals such as small crustaceans. When feeding, they swallow the food and digest it in the stomach instead of outside the body.
three
The species living in the deep sea feed on cilia filtration, and the sediment organic matter falling on the body surface is swept into the step belt ditch by the cilia function to form a food cord, which is then sent to the entrance, such as the maple starfish.Another exampleChicken Claw Starfish(Henrica), there are cilia in the gastric caecum, and the movement of cilia helps to pump food into the stomach.[2]
The digestive tract of starfish is also arranged in five spokes. The mouth is located in the center of the mouth, surrounded by a perioral membrane, on which there are circular muscles and sphincters, regulating the expansion and contraction of the mouth.After the mouth is the esophagus, which is very short and then enters the enlarged stomach.There is a horizontal contraction on the gastric wall, which separates the stomach into a cardiac stomach near the oral side and a smaller pyloric stomach near the contraoral side.When taking food, the cardia and stomach often turn outward, and then retract together after wrapping the food.There are 2-10 gastric ligaments originating from the coelom on the gastric wall, which are connected to the bone plate.A pyloric tube extends from the pyloric stomach to each wrist, and immediately divides into two branches after entering the wrist, reaching the end of the wrist.The pyloric duct divides into two tubes along the way, and a large number of gland cells surround it to form the pyloric blind sac (pyloric cecv). It is actually a digestive gland, also known as the liver, with the function of secreting digestive enzymes, absorbing and storing nutrients.After the pylorus and stomach, there is a very short intestine. There are five rectal cecvms around the rectum at the end of the intestine. Finally, a very small anal opening is in the center of the anti oral surface.Some species even have no intestines, and indigestible food is usually still vomited from the mouth.The inner wall of the digestive tract is coated with ciliated epithelium. There are developed glandular cells on the cardia and stomach wall to secrete digestive enzymes, especially the pyloric blind sac can secrete protease, amylase and lipase.Food can be partially digested in vitro, mainly in the stomach for extracellular digestion, and in the pyloric blind sac for intracellular digestion.[2]
Peripheral blood system
Announce
edit
Echinodermata have no specialcirculatory organs, the circulation function may be performed by the body cavity fluid.There are developed coeloms in the central disc and wrist, which surround the organs and are full of coelom fluid. The flow of coelom fluid is caused by the cilia of coelom cells swinging to complete the transportation of nutrients.The coelom cells in the coelom fluid may come from the coelom membrane, or it is said that they come from the adherent body and have phagocytic function.Because the coelomic fluid is isotonic with seawater, it is rarely able to regulate, so echinoderms can only live in seawater, and rarely invade estuaries.Only a few species can live in low salt water (8-18 ‰), and the rest live in standard seawater (salinity 35 ‰).Echinoderm has a special blood system (heathe) and perihe alsyste.[2]
The blood system consists of a series of pipes corresponding to the water pipe system, which are filled with liquid, and there are also coelomic cells in the liquid.There are circular blood vessels below the circular water tube on the oral surface, and radial blood vessels also extend to each wrist, which are also located below the radial water tube.The gland of a dark brown spongy tissue extending from the circular blood vessel to the contraoral surface is accompanied by the stone tube, which is called axial gland. It may have a certain pulsating capacity.The gastric blood ring protrudes near the contraoral surface and branches to the pyloric blind sac. When reaching the contraoral surface, the blood ring forms on the contraoral surface and branches to the gonad.There is a knapsack near the sieve plate, which also has pulsating ability and can promote the flow of liquid.The function of the blood system is still uncertain, which may be related to the transport of substances.Surrounding and accompanying the blood system is the surrounding blood system. Except that there is no surrounding blood ring around the stomach, the rest completely accompany.In fact, it is part of the body cavity and forms a set of sinus spaces outside the blood system.Little is known about its role.[2]
The respiration and excretion of starfish are mainly carried out by skin gills, tube feet and body surface.The skin gill is a tumor like substance protruding from the inner and outer layers of epithelial cells of the body wall, and the body cavity fluid also flows into it.The ciliary function of the coelomic epithelium in the skin gill makes the coelomic fluid flow in it, and the ciliary epithelium in the outer layer of the skin gill makes the water flow on the body surface, so that the gas exchange continues.At the top of the banded skin gill, it is branched and located in the gap between the spinous process bundles.Tubopods also play an important role in gas exchange, especially in the species with underdeveloped skin gills.Experiments have proved that the oxygen consumption is reduced by 60% when the step belt groove is closed and the tube foot cannot breathe.The nitrogenous waste of starfish is also discharged from the skin gills and tube feet. The injection of living dye into the body cavity shows that the metabolic waste is taken up by the body brain cells, and then moved to the skin gills after full load, and gathered at the top of the skin gills. Later, when the skin gills shrink, these body cavity cells are discharged from the body.Some coelomic cells loaded with metabolites enter the sucker at the end of the tube foot and then discharge from the sucker.Other metabolites come from the pyloric caecum, which is then spit out from the mouth with undigested food residues.[2]
nervous system
Announce
edit
The nervous system of starfish and all echinoderms is scattered, does not form ganglia or nerve centers, and is closely connected with epithelial cells.It is generally believed that starfish includes three unconnected neural structures:
one
The external nervous system is located under the epidermal cells of the body wall of the oral surface. It forms a nerve ring around the perioral membrane of the oral surface, from which the nerves innervate the esophagus and around the mouth, and branch radial nerves to each wrist.The cross section of the radial nerve is in a "V" shape, reaching the end of the wrist along the center of the bottom of the girdle groove, and sending out nerves to the tube foot and the altar sac along the way.In addition to these visible nerve cords, they are also interconnected with the subepithelial nerve fiber plexus.The external nervous system is the sensory nerve, which originates from the ectoderm and is the most important nerve structure.
two
The entoural nervous system is a pair of marginal nerve cords formed by the thickening of the superior subcutaneous nerve plexus at the outer edge of the step band groove. It sends out nerves to the muscles of the paired step band bone plates, and forms a nerve plexus below the body cavity membrane to innervate the muscle layer of the body wall.
three
The lower nervous system is located on the tube wall of the peripheral blood system (i.e., below the coelom), also known as coelomic nerve, and is also composed of a perinatal nerve ring and five interlaminar nerve thickening areas.The internal nerve and the inferior nerve are both motor nerves, originating from the mesoderm, which is the only exception in the animal kingdom.[2]
The nervous system plays an important role in movement.Some experiments have proved that if the radial nerve of one wrist is cut off, the coordinated movement of the tube and foot of all wrists will disappear.If the ring nerve is cut off between the two wrists, all movements are inhibited, which indicates that there is a nerve center between the radial nerve and the ring nerve, and this center generally exists on the dominant wrist, which controls the coordination of other wrists.Most of the five wrists can be temporarily used as the dominant wrist, while a few of the five wrists are permanent dominant wrists.There is a red eye spot at the end of each wrist and below the tentacle, which is its only sense. It is composed of 80-200 pigment cup eyelets.Each eyelet consists of a cup of epithelial cells, in which there are red pigment particles. The thickening part of the cuticle outside the eyelet acts as a crystal. Even if the eyespot is covered, it can react to light.There are a large number of neurosensory cells in the epidermis. These cells have long projections and finally join the epithelial nerve plexus. They form receptors and respond to light, touch and chemical stimuli.These sensory cells are distributed on the whole body surface, and are particularly abundant at the edges of the tube feet, tentacles, and gait grooves.[2]
The nervous system of starfish
Reproductive development
Announce
edit
The vast majority of starfish are dioecious, with a total of 10 gonads, each of which is composed of a cluster of grape shaped tubes.In the immature stage, the glands are small and located at the base of the five wrists.During the reproductive period, the glands are very large, almost filling the entire wrist.The gonads are usually white in males and orange in females. Each gonad has a genital pore located on the central disc of the wrist base of the contraoral surface.Acer starfish（Astropectinidae）Each wrist has many gonads, arranged in rows, and the genital opening is on the oral surface.A few species are hermaphrodite, such as a petrel（Asterina gibbose）However, male precocious, that is, when young, male germ cells will be produced, and when older, they will become female individuals and produce eggs.[2]
germ cellThey all come from the body cavity epithelium, and spawning and fertilization are carried out in seawater.Generally, the presence of female germ cells can stimulate other individuals to ovulate or male ovulate, or the presence of sperm can stimulate female ovulation.Experiments have proved that the maturation and discharge of eggs are stimulated by the secretion of neurosecretory cells of the radial nerve.Most species have a large number of eggs, up to 2.5 million, small eggs, few yellow eggs, and indirect development.A few species lay fewer eggs, larger eggs and more yolks, which are directly developed, but the eggs are incubated by the mother.The method of incubation varies from species to species. For example, some species of Pterasteridae incubate their eggs on the oral surface;Some eggs lay on the central disc of the contraoral surface, and long spines grow at the wrist base to protect the eggs and incubate in them.[2]
Most species also undergo a free swimming larval stage.Cleavage and formation of fertilized eggs by radiationblastulaWhen they reach the gastrula stage, they begin to swim freely.At first, there are cilia on the whole surface. With the development of cilia, they are limited to certain cilia bands. The front end starts from the mouth and the back end ends in front of the anus. The larvae swim and feed on the cilia bands.Later, the ciliary band in front of the mouth forms a ring, and a triad cavity appears in the body, which is called a double feather larva.It is symmetrical on both sides.It takes several weeks to develop to the double feather larva stage.After feeding and swimming for a period of time, the two feathered larvae appear three attached short wrists at the front end, with adhesive cells at the top and sucker formed by adhesive cells at the base of the wrist, which is called brachiolaria.[2]
Then it is fixed on the base with mucocytes and suckers (banding class does not form brachycarpus larvae), and then begins to metamorphose.The front mouth leaf of the larva is specialized into a fixed handle, and the adult structure is formed from the rear end of the larva. The left side of the larva becomes the mouth surface, the right side becomes the anti mouth surface, and the adult appears the wrist.The digestive tract of larvae degenerates, and that of adults occurs radially symmetrically.The posterior body cavity of the larva becomes the body cavity of the adult, and part of the posterior body cavity also becomes the peripheral blood system.The left anterior and middle body cavities (i.e., axial cavity and water cavity) develop into a water pipe system, while the right anterior and middle body cavities degenerate. At the same time, the left water cavity has 5 pairs of projections, and each pair enters the developing wrist.These 5 pairs of protuberances represent the first pair of tubular feet respectively.With the formation of more tube feet, the tube feet are attached, and the original fixed front end is free, and bone plates are constantly formed.It took about two months to develop into a young starfish. At this time, the diameter was only about 1 mm. The body changed from bilateral symmetry to radial symmetry, and the metamorphosis was completed.[2]
The growth rate and life span of larvae vary from species to species, generally reaching sexual maturity after 1-2 years and a few 4-5 years.The growth can last for several years, and the life span can reach several years to more than 10 years, and some species can reach more than 30 years.Some starfish can reproduce asexually, that is, one starfish can become two by splitting the central disk.Generally speaking, starfish have a strong regenerative ability. A wrist with a part of the central disk can be regenerated into a whole, especially with a sieve plate.Even oneRefers to starfishA cut wrist can also regenerate the central disc and other wrists, but the regenerated part is smaller than the normal one.[2]
Starfish is a kind of echinoderm that lives in the sea. They have strong reproductive capacity and can live for up to 35 years.There are about 1500 kinds of starfish in the world. Most of them are bred through in vitro fertilization and do not need mating.Male starfish have a pair on each wristtestis, they willspermWhen discharged into the water, the female also excretes thousands ofegg。Sperm and egg meet in water, complete fertilization, and form new life.From the fertilized egg, young bodies, also known as starfish, are born.So let their eggs not reproduce.
Some researchers found that some starfish have the habit of seasonal pairing, that is, male starfish lie on top of female starfish, with five wrists interlaced.This behavior is considered to be related to reproduction, but its true function has not yet been confirmed.
Wrist has two distinct marginal plates;No skin gills;Living on the soft seabed, there are two rows of pipe feet without suction cups, and they are arranged in two rows in the step belt ditch, which is conducive to living or crawling in the sediment caves.Most deep-sea starfish belong to this order, such as Asteropectinidae, which feeds by filtering cilia.[2]
The marginal plate is very small, and the fork spines are simple or lacking.There are clusters of spines, and tube feet have suction cups, but fork spines are rare.Common camel petrel on rocky seabed in Europe（Asterina gibbosa）。Northern Neptune（Crossaster）And Solar Neptune（Solaster）There are many short wrists and a wide body disk.Ratchet starfish（Crossaster papposus）There are 15 wrists.[2]
There are double valve forked spines with long stems, which can protect or feed.Common species that feed on bivalves in shallow water, including the Red Sea Panhandle distributed in northern Europe（Asterias rubens）, the spiny sea wheel from the Bering Sea to the Korean Peninsula.Starfish with short spines on the west coast of North America（Pisaster brevispinus）It is 65 cm long and is one of the largest starfish in the world. It feeds on sea urchins, etc.Pycnopodia helianthides from Alaska to California have 15-24 wrists.There are up to 50 wrists in the genus Heliaster in Central America.[2]
Distribution area
Announce
edit
Distribution of starfishworldAll sea areas, to the norththe pacific oceanThe region has the most varieties.It is vertically distributed from the intertidal zone to the depth of 6000 meters.Magnetic Neptune isDeep-sea animalsAnd the habitat depth is not less than 1000m.Starfish live on various sediments, but rarely on soft mud.The benthic platycladus does not have strict requirements on the bottom material, and it often moves with the number of bivalves it eats.
environmental value
Announce
edit
GermanyLeibniz Oceanographic Research Institute once issued a bulletin saying that the latest research found that echinoderms such as starfish play an important role in the marine carbon cycle, and they can directly absorb carbon from seawater during the formation of exoskeleton.
Echinodermata live in the sea bottominvertebrate, divided intoStarfish、Echinacea, SerpentidaHolothuriansandCrinoidsAnd other 5 types, whose figures are all over the oceans.It was found that echinoderms would absorb carbon from seawater and form exoskeleton in the form of inorganic salts (such as calcium carbonate).After their death, most of the carbon containing substances in their bodies will remain at the bottom of the sea, thus reducing the carbon entering the atmosphere from the sea.In this way, echinoderms absorb about 100 million tons of carbon every year.
It is known that the acidity of seawater will rise after the greenhouse gases generated by burning fossil fuels enter the ocean, which will hurtCoral reefAnd shellfish.This time, the researchers found that acidic seawater has a significant impact onEchinodermaThe invasion of calcium is also very serious, making it impossible for such creatures to form solid calcium containing exoskeletons.
Special functions
Announce
edit
Monitor
Starfish
Sea animals covered with echinoderms - starfish have a strange star shaped body, which usually has five long, discoid bodiesantenna, but can't see.People always think that starfish rely on these antennae to identify direction, but it is not.Scientists from the United States and Israel have found that starfish are all "monitors".Why can starfish use their bodies to see everything?Yes, why can starfish use their bodies to see everything.
It turns out that starfish have many tiny crystals on their spiny skin, and each crystal can play the role of the eye to obtain information around.Scientists dissected starfish and found that every tiny crystal on the spines of starfish is a perfect lens. It is known that its size is far smaller than the lens made by human beings using existing high-tech.The innumerable lenses in the spines of starfish have the property of concentrating light. These lenses enable starfish to observe information from all directions at the same time and grasp the surrounding conditions in time.Before that, scientists thought that the echinoderm of starfish was highly photosensitive. It could decide what kind of concealment and prevention measures to take by changing the intensity of light around its body. In addition, it could also confuse the "enemy" by changing its own color.Scientists say that this unusual visual system on starfish is the first time to be discovered.Scientists predict that copying this tiny lens will make breakthroughs in optical technology and printing technology.
ecologyBalancing starfish is an indispensable link in the marine food chain.Its prey keepsBiotaFor example, on the west coast of the United States, there is a kind of Wenji starfish that often prey on the sea rainbow closely attached to the reef.In this way, we can prevent the excessive reproduction of the sea rainbow, and prevent the sea rainbow from invading the territory of other creatures, so as to maintainBiotaThe role of balance.[3]
Regenerative capacity
Starfish's unique skill is that it has skills.If you tear the starfish into several pieces and throw them into the sea, each piece will soon grow out of the lost part, thus growing into several complete new starfish.For example, sand starfish can grow a complete new starfish by keeping a centimeter long wrist, while some starfish are more capable, and can grow a complete new starfish as long as they have a broken arm.After the wrist and body disc of a starfish are damaged or cut, they can regenerate naturally.Any part of a starfish can regenerate a new starfish[4]。
Because starfish have such amazing regenerative ability, it is a trivial matter for them to break their arms and limbs.Known,scientistWe are exploring starfishregenerateThe mystery of ability, so as to get inspiration from it and seek a new medical method for mankind.Scientists found that when a starfish is injuredCellsIs activated, and these cells contain all the missing parts of the bodygeneAnd cooperate with other organizations to regenerate the lost wrist or other parts.
Therefore, some kinds of starfish have developed the ability of asexual reproduction through this super regenerative way, so they don't need to mate any more.However, most starfish do not usually reproduce asexually.
Hazard prevention
Announce
edit
Main hazards
The latest report in 2007,the PhilippinesMore than half of the 25000 square kilometers of coral reefs were attacked by the starfish army.Starfish are also terrible.Since 2006, a large number of starfish have burst out in the coastal areas of northern China,densityUp to 300 pieces/square meter, 3-5 mu per day in peak periodsea areaIt can collect more than 500 kilograms of starfish.Starfish are mainly concentrated in LaoshanJiaozhou Bay、Tangdao BayAnd Jiaonan sea area, eating abaloneRuditapes philippinarum 、Scallop in ShellOne starfish can eat more than a dozen scallops a day, which is amazing, causing huge economic losses to the shellfish breeding industry.In 2006 alone, the loss of abalone farming in Jiaonan region was more than 40 million yuan due to starfish disasters;In 2007, only Qingdao Haifeng Aquaculture Company lost more than 30 million yuan in the breeding of variegated clams due to starfish ingestion.According to preliminary statistics, since March 2007, 60% of the 160000 mu Philippine clams bred in Jiaozhou Bay have been attacked by starfish, with a disaster rate of 70% - 80%, and some areas as high as 90%. A 60 horsepower fishing boat can catch 800-1000 kg of starfish a day in Jiaozhou Bay breeding area for breedingfishermanThe losses were heavy.[5]
Prevention and control methods
Controlling the spread of starfish has attracted the attention of governments and experts all over the world. It is urgent to reduce the economic losses of shellfish farming.stayJapanEvery year, millions of funds are spent to control the harm of starfish,U.S.AEvery year, oyster farms spend a lot of manpower and financial resources to deal with the harm.At the same time, the harm of starfish has attracted the attention of governments at all levels.
In view of the serious negative impact of starfish flooding on fishery production, combined with the current production practice, the following research countermeasures are mainly explored:
one
Strengthen publicity and guidance, and strengthen fishermen's awareness of starfish hazards.From a scientific point of view, we should do a good job of propaganda and guidance for fishermen to eliminate their numb consciousness.If necessary, trawl fishing and manual fishing shall be adopted, and ground roll cages shall be arranged on the seabed outside the aquaculture area for trapping, and the effects of various fishing methods shall be compared.As starfish have strong reproductive capacity, the captured starfish should be treated on land, which can be used for viscositysoilDo not tear them up and throw them back into the sea to prevent starfish from regenerating.Starfish is very dangerous. Never let starfish breed. He is as long as a gecko's tail, and one end can become countless.
two
Biological control research starfishnatural enemyThe species and quantity of organisms, understand the mechanism of killing starfish larvae, and use the method of breeding starfish natural enemies to prevent starfish from killing starfish larvaeCultured shellfishIt is a kind of environmental protection method worth advocating.
three
As an edible part of starfish, starfish yellow is rich in trace amountselement、vitamin、FatIt can be processed and used as a new type of nutrition and non-toxicMarine foodRaw materials.In recent years, the medicinal value of starfish has been gradually valued. Many marine drug enterprises have developed starfish nutrient capsules and other products, which have significant effects on regulating human immune function, curing diseases and strengthening the body.In addition, starfish can also be dried to make agricultural fertilizer andtourist cityMake it intoArts and Crafts, thus increasing the added value.Marine science and technology workers should vigorously study and publicize the medicinal and edible value of starfish, quickly transform scientific and technological achievements into productivity, assist enterprises in taking the path of starfish large-scale processing, make people accept and recognize the important contribution of starfish to mankind, consciously and actively catch starfish, and make them become valuable and harmful.
four
Establish the corresponding starfish prevention committee to organize professional researchers toQingdaoInvestigate the distribution, harm and development trend of starfish along the coast, especially in Jiaozhou Bay.Formulate corresponding laws and regulations, strictly inspect and quarantine ships entering from other places, and restrict the transmission of tool carriers carrying starfish larvae between different sea areas.
five
Strengthen supervision and inspection, and strictly standardize operation behavior.The time for removing starfish shall be determined according to the early warning situation, and shall be implemented after being approved by the fishery administration department.The use of nets is limited to large mesh ground cage nets or conch trawls, and the illegal operations in the name of removing starfish and destroying fishery resources will be severely punished according to relevant regulations.[6]
