Jellyfish
Sea nettle, Chrysaora quinquecirrha
Scientific classification
Kingdom: Animalia Phylum: Cnidaria Class: Scyphozoa Goette, 1887
Orders
Stauromedusae Coronatae Semaeostomeae Rhizostomae

Jellyfish are marine invertebrates belonging to the class Scyphozoa of the phylum Cnidaria. The stinging sea nettle ( Chrysaora quinquecirrha) is a Species of Jellyfish occurring particularly in Atlantic estuaries Cnidaria (naɪˈdɛəriə is a phylum containing some 9000 Species of Animals found exclusively in aquatic mostly marine, environments This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Stauromedusae, or the stalked jellyfishes, is an order of Jellyfish within the Cnidaria phylum that are unique in that they do not enter Crown jellyfishes are the eight families of Jellyfish that belong to the order Coronatae. Semaeostomeae (literally "flag mouth" is an order of large Jellyfish characterized by four long frilly Oral arms flanking its quadrate "mouth" Rhizostomae or Rhizostomeae is an order of Jellyfish. Species of this order have neither Tentacles nor other structures at the bell's edges An invertebrate is an Animal lacking a Vertebral column. The group includes 98% of all animal Species — all animals except those in the Chordate A class is the Taxonomic rank in the Biological classification of organisms in Biology below phylum and above order. A phylum ( Plural: phyla) is a Taxonomic rank between Kingdom and above Class. Cnidaria (naɪˈdɛəriə is a phylum containing some 9000 Species of Animals found exclusively in aquatic mostly marine, environments They can be found in every ocean in the world and even in some fresh water. An ocean (from Greek, ''Okeanos'' (Oceanus) is a major body of saline water, and a principal component of the Hydrosphere. The term "jellyfish" is a common name, and therefore does not imply any systematic relationship to vertebrate fish — jellyfish are cnidarians. Cnidaria (naɪˈdɛəriə is a phylum containing some 9000 Species of Animals found exclusively in aquatic mostly marine, environments The term "jellyfish" is also applied to some close relatives of true scyphozoans, such as the Hydrozoa and the Cubozoa. Hydrozoa ( hydrozoans) are a Taxonomic class of very massive predatory animals which can be solitary or colonial and which mostly live in saltwater Box jellyfish are invertebrates belonging to the class Cubozoa, named for their Cube -shaped medusae.

Contents 1 Anatomy and morphology 1.1 Body systems 1.2 Jellyfish blooms 1.3 Life history 2 Etymology and taxonomic history 3 Importance to humans 3.1 Culinary uses 3.2 In biotechnology 3.3 In captivity 3.4 Toxicity to humans 4 See also 5 References 6 External links

Anatomy and morphology

The body of an adult jellyfish consists of a bell shape producing jelly and enclosing its internal structure, from which tentacles are suspended. Tentacles can refer to the elongated flexible organs that are present in some animals especially Invertebrates and sometimes to the hairs of the leaves of some insectivorous Each tentacle is covered with cells called cnidocytes, that can sting or kill other animals. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called A cnidocyte, cnidoblast or nematocyte, is a type of Venomous cell unique to the Phylum Cnidaria ( Corals Most jellyfish use these cells to secure prey or for defense. Others, such as the Rhizostomae, do not have tentacles at all. Rhizostomae or Rhizostomeae is an order of Jellyfish. Species of this order have neither Tentacles nor other structures at the bell's edges

Jellyfish lack basic sensory organs and a brain, but their nervous systems and rhopalia allow them to perceive stimuli, such as light and odor, and respond quickly. The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain The nervous system is a Network of specialized cells that communicate information about an animal's surroundings and itself Rhopalia (singular rhopalium) are small sensory structures of scyphozoan and Cubozoan Jellyfish; in Aurelia they lie in marginal They feed on small fish and zooplankton that become caught in their tentacles. Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Zooplankton are the Heterotrophic (sometimes detritivorous) type of Plankton. Most jellyfish are passive drifters and slow swimmers, as their shape is not hydrodynamic. Fluid dynamics is the sub-discipline of Fluid mechanics dealing with fluid flow: Fluids ( Liquids and Gases in motion Instead, they move so as to create a current forcing the prey within reach of their tentacles. They do this by rhythmically opening and closing their bell-like body. Their digestive system is incomplete: the same orifice is used to take in food and expel waste. Digestion is the breaking down of chemicals in the body into a form that can be absorbed The body of an adult is made up of 94–98% water. The bell consists of a layer of epidermis, gastrodermis, and a thick, intervening layer called mesoglea that produces most of the jelly. The gastrodermis is the inner layer of cells that lines a Gastrovascular cavity of Cnidarians. Mesoglea, also known as ectoplasma, is the clear inert jellylike substance that makes up most of the bodies of Jellyfish, Comb jellies and certain primitive

Body systems

A jellyfish detects the touch of other animals using a nervous system called a "nerve net", located in its epidermis. For the album by Brian Eno, see Nerve Net (album. A nerve net is a type of simple Nervous system that is found in members of the phylum Touch stimuli are conducted by nerve rings, through the rhopalial lappet, located around the animal's body, to the nerve cells. Rhopalia (singular rhopalium) are small sensory structures of scyphozoan and Cubozoan Jellyfish; in Aurelia they lie in marginal Jellyfish also have ocelli: light-sensitive organs that do not form images but are used to determine up from down, responding to sunlight shining on the water's surface. An ocellus (plural ocelli) is a type of Photoreceptor organ in animals

Jellyfish don't have a specialized digestive, osmoregulatory, central nervous, respiratory, or circulatory systems. Osmoregulation is the active regulation of the Osmotic pressure of bodily fluids to maintain the Homeostasis of the body's Water content that is it keeps In Vertebrates the central nervous system ( CNS) is the part of the Nervous system which is enclosed in the Meninges. In living organisms a respiratory system functions to allow Gas exchange. This is an article about the rock music band "Circulatory System" They digest using the gastrodermal lining of the gastrovascular cavity, where nutrients are absorbed. The gastrodermis is the inner layer of cells that lines a Gastrovascular cavity of Cnidarians. Gastro vascular cavity, as the name indicates functions in both Digestion and Gas exchange. They do not need a respiratory system since their skin is thin enough that the body is oxygenated by diffusion. Diffusion is the net movement of particles (typically molecules from an area of high concentration to an area of low concentration by uncoordinated random movement They have limited control over movement and mostly free-float, but can use the hydrostatic skeleton of the water pouch to accomplish vertical movement through pulsations of the disc-like body. A hydrostatic skeleton or hydroskeleton is a structure found in many Cold-blooded organisms and soft-bodied animals consisting of a fluid-filled cavity the Coelom

The outer side of a jellyfish is lined with a jelly-like material called ectoplasm (ecto meaning outer and plasm meaning living matter). The ectoplasm typically contains a smaller amount of protein granules and other organic compounds than inner cytoplasm, also referred to as endoplasm (endo meaning inner). Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl In cell biology, a granule can be any structure barely visible by light microscopy An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon.

Jellyfish blooms

Many species of jellyfish are capable of congregating into large swarms or "blooms", consisting of hundreds of individuals. The SWARM Remote Weapon System (Stabilised Weapon And Reconnaissance Mount is a fully armored Remote weapon system designed and built by the Thales Group in The formation of these blooms is a complex process that depends on ocean currents, nutrients, temperature and ambient oxygen concentrations. An ocean current is continuous directed movement of Ocean water. A nutrient is food or chemicals that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment Jellyfish sometimes mass breed during blooms. During such times of rapid population expansion, some people will raise ecological concerns about the potential noxious effects of a jellyfish "outbreak". Marine biology is the scientific study of living Organisms in the Ocean or other marine or Brackish bodies of water

According to Claudia Mills of the University of Washington, the frequency of jellyfish blooms may be attributed to humans' impact on marine systems. See Washington (disambiguation for other uses The University of Washington, founded in 1861, is a public research University She says that the breeding jellyfish may merely be filling ecological niches formerly occupied by overfished creatures. In Ecology, a niche (pronounced nich nēsh or nish A shorthand definition of niche is how an organism makes a living Overfishing occurs when Fishing activities reduce fish stocks below an acceptable level Jellyfish researcher Marsh Youngbluth further clarifies that "jellyfish feed on the same kinds of prey as adult and young fishes, so if fish are removed from the equation, jellyfish are likely to move in. "

Increased nutrients in the water, ascribed to agricultural runoff, have also been cited as an antecedent to the proliferation of jellyfish. Surface runoff is a term used to describe when soil is infiltrated to full capacity and excess Water, from Rain, Snowmelt, or other sources flows Monty Graham, of the Dauphin Island Sea Lab in Alabama, says that "ecosystems in which there are high levels of nutrients . The Dauphin Island Sea Lab (DISL is Alabama 's primary marine education and research center Alabama (formally the State of Alabama;) is a State located in the southern region of the United States of America. . . provide nourishment for the small organisms on which jellyfish feed. In waters where there is eutrophication, low oxygen levels often result, favoring jellyfish as they thrive in less oxygen-rich water than fish can tolerate. Eutrophication is an increase in chemical Nutrients -- typically compounds containing Nitrogen or Phosphorus -- in an Ecosystem, and may occur The fact that jellyfish are increasing is a symptom of something happening in the ecosystem. "^[1]

By sampling sea life in a heavily fished region off the coast of Namibia, researchers found that jellyfish have overtaken fish in terms of biomass. Namibia, officially the Republic of Namibia, is a country in Southern Africa on the Atlantic coast Biomass, in Ecology, is the mass of living biological organisms in a given area or Ecosystem at a given time The findings represent a careful, quantitative analysis of what has been called a "jellyfish explosion" following intense fishing in the area in the last few decades. The findings were reported by Andrew Brierley of the University of St. Andrews and his colleagues in the July 12, 2006 issue of the journal Current Biology.

Areas which have been seriously affected by jellyfish blooms include the northern Gulf of Mexico. The Gulf of Mexico ( Spanish: Golfo de México) is the ninth largest Body of water in the world In that case, Graham states, "Moon jellies have formed a kind of gelatinous net that stretches from end to end across the gulf. "^[1]

Life history

Most jellyfish pass through two distinct life history phases (body forms) during their life cycle. A life cycle is a period involving 1 Generation of an Organism through means of Reproduction, whether through Asexual reproduction or Sexual The first is the polypoid stage, when the jellyfish takes the form of either a sessile stalk which catches passing food, or a similar free-floating configuration. In Zoology, a polyp is one of two forms of individuals found in many species of Cnidarians The two are the polyp or hydroid and the medusa. Sessile is a term in Biology with two distinct meanings In botany and medicine In Botany, sessile means "without a stalk The polyp's mouth and tentacles face upwards, reminiscent of the hydroid stage of the somewhat closely related anthozoan polyps, also of the phylum Cnidaria. Anthozoa is a class within the phylum Cnidaria that contains the Sea anemones and Corals Unlike other cnidarians anthozoans do not have a medusa

In the second stage, the jellyfish is known as a medusa. In Biology, a medusa (plural medusae is a form of Cnidarian in which the body is shortened on its principal axis and broadened sometimes greatly in contrast Medusae have a radially symmetric, umbrella-shaped body called a bell. "Bilateral symmetry" redirects here For bilateral symmetry in mathematics see Reflection symmetry. The medusa's tentacles are fringe-like protrusions from the border of the bell. (Medusa is also the word for jellyfish in Romanian, Hebrew, Croatian, Spanish, French, Italian, Hungarian, Russian and Bulgarian. )

Jellyfish are dioecious; that is, they are either male or female. Plant sexuality covers the wide variety of Sexual reproduction systems found across the Plant kingdom In most cases, to reproduce, a male releases his sperm into the surrounding water. A spermatozoon or spermatozoan ( pl spermatozoa) from the Ancient Greek σπέρμα (seed and ζῷον (living being and more commonly known The sperm then swims into the mouth of the female, allowing the fertilization of the ova. An ovum (plural ova) is a Haploid Female reproductive cell or Gamete. However, moon jellies use a different process. The eggs become lodged in pits on the oral arms, which form a temporary brood chamber to accommodate fertilization.

After fertilization and initial growth, a larval form, called the planula, develops from the egg. A planula is the free-swimming flattened ciliated, bilaterally symmetric Larva of a Jellyfish, a Hydrozoan Cnidarian or The planula is a small larva covered with cilia. A cilium (plural cilia) is an Organelle found in eukaryotic cells Cilia are tail-like projections extending approximately It settles onto a firm surface and develops into a polyp. In Zoology, a polyp is one of two forms of individuals found in many species of Cnidarians The two are the polyp or hydroid and the medusa. The polyp is cup-shaped with tentacles surrounding a single orifice, resembling a tiny sea anemone. Sea anemones are a group of water dwelling predatory animals of the order Actiniaria; they are named after the Anemone, a terrestrial Flower After an interval of growth, the polyp begins reproducing asexually by budding and is called a segmenting polyp, or a scyphistome. Budding (also called burgeoning) is the formation of a new Organism by the protrusion of part of another organism New scyphistomae may be produced by budding or new, immature jellies called ephyra may be formed. Many jellyfish species are capable of producing new medusae by budding directly from the medusan stage.

Most jellyfish have a lifespan of two and a half months; few live longer than six months but one species can live as long as 30 years and another species, T. nutricula, is effectively immortal. Turritopsis nutricula is a Hydrozoan with a life cycle in which it reverts back to the Polyp stage after becoming sexually mature.

Etymology and taxonomic history

Since jellyfish are not fish, some people consider the term "jellyfish" a misnomer, and instead use the term "jellies" or "sea jellies". Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two A misnomer is a term which suggests an interpretation that is known to be untrue The word "jellyfish" is also often used to denote either hydrozoans or the box jellyfish, the cubozoans. Hydrozoa ( hydrozoans) are a Taxonomic class of very massive predatory animals which can be solitary or colonial and which mostly live in saltwater Box jellyfish are invertebrates belonging to the class Cubozoa, named for their Cube -shaped medusae. The class name, Scyphozoa, comes from the Greek word skyphos, denoting a kind of drinking cup and alluding to the cup shape of the organism. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly

A group of jellyfish is often called a "smack". ^[2]

Importance to humans

Culinary uses

Jellyfish are an important source of food to the Chinese community and in many Asian countries. ^[3] Only jellyfish belonging to the order Rhizostomeae are harvested for food. This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Rhizostomae or Rhizostomeae is an order of Jellyfish. Species of this order have neither Tentacles nor other structures at the bell's edges Rhizostomes, especially Rhopilema esculentum in China (Chinese name: 海蜇 hǎizhē) and Stomolophus meleagris (cannonball jellyfish) in the United States, are favoured because they are typically larger and have more rigid bodies than other scyphozoans. Rhopilema is a Genus of Jellyfishes Species include R esculentum (" Bizen kurage " Kishinouye 1891 * R The Cannonball Jellyfish ( Stomolophus meleagris) is a species of Jellyfish in the family Stomolophidae. Furthermore, their toxins are innocuous to humans. ^[3]

Traditional processing methods, carried out by a Jellyfish Master, involve a 20 to 40 day multi-phase procedure in which the umbrella and oral arms are treated with a mixture of table salt and alum, and compressed. Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants For the purely-slang term alum meaning "graduate" see Alumnus. ^[3] The gonads and mucous membranes are removed prior to salting. Processing reduces liquidation, off-odors and the growth of spoilage organisms, and makes the jellyfish drier and more acidic, producing a "crunchy and crispy texture. "^[3] Jellyfish prepared this way retain 7-10% of their original, raw weight, and the processed product contains approximately 95% water and 4-5% protein, making it a relatively low calorie food. Calorie restriction, or caloric restriction (CR aims to improve health and slow the aging process by limiting dietary energy intake ^[3] Freshly processed jellyfish has a white, creamy color and turns yellow or brown during prolonged storage.

In China, processed jellyfish are desalted by soaking in water overnight and eaten cooked or raw. The dish is often served shredded with a dressing of oil, soy sauce, vinegar and sugar, or as a salad with vegetables. ^[3] In Japan, cured jellyfish are rinsed, cut into strips and served with vinegar as an appetizer. ^[3][4] Desalted, ready-to-eat products are also available. ^[3]

Fisheries have begun harvesting cannonball jellyfish along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asian nations. ^[3]

In biotechnology

In 1961, green fluorescent protein (GFP) was discovered in the jellyfish Aequorea victoria by scientists studying bioluminescence. Aequorea victoria, also called the crystal jelly, is a Bioluminescent Jellyfish that is found off the west coast of North America The green fluorescent protein ( GFP) is composed of 238 Amino acids (26 Aequorea victoria, also called the crystal jelly, is a Bioluminescent Jellyfish that is found off the west coast of North America Bioluminescence' is the production and emission of Light by a living Organism as the result of a chemical reaction during which chemical energy is converted This protein has since become a quite useful tool in biology. Its use is mainly for scientists studying in which tissues genes are expressed. The technique, using genetic engineering, fuses the gene of interest to the gene of GFP. The fused DNA is then put into a cell, to generate either a cell line or (via IVF techniques) an entire animal bearing the gene. In the cell or animal, the artificial gene gets turned on in the same tissues and the same time as the normal gene. But instead of making the normal protein, the gene makes GFP. One can then find out what tissues express that protein -- or at what stage of development -- by shining light on the animal or cell, and looking for the green fluorescence. The fluorescence shows where the gene of interest is expressed. ^[5] Jellyfish are also harvested for their collagen, which can be used for a variety of scientific applications including the treatment of rheumatoid arthritis. Collagen is the main Protein of Connective tissue in Animals and the most abundant protein in Mammals making up about 50% of the whole-body protein Rheumatoid arthritis ( RA) is a chronic systemic autoimmune disorder that causes the Immune system to attack the Joints, where

In captivity

Jellyfish are commonly displayed in aquaria in many countries. Often the tank's background is blue and the animals are illuminated by side light to produce a high contrast effect. In natural conditions, many jellies are so transparent that they are almost impossible to see.

Holding jellyfish in captivity presents other problems. For one, they are not adapted to closed spaces. They depend on currents to transport them from place to place. To compensate for this, professional exhibits feature precise water flows, typically in circular tanks to prevent specimens from becoming trapped in corners. The Monterey Bay Aquarium uses a modified version of the kreisel (German for "spinning top") for this purpose.

Toxicity to humans

When stung by a jellyfish, first aid may be needed immediately. First aid is the provision of initial care for an Illness or Injury. The stings of true Scyphozoan jellyfish are not generally deadly, though species of the completely separate class Cubozoa (box jellyfish) such as the famous and especially toxic Irukandji can be fatal. Box jellyfish are invertebrates belonging to the class Cubozoa, named for their Cube -shaped medusae. The Irukandji jellyfish ( Carukia barnesi and Malo kingi) are small extremely Venomous Jellyfish that are found mostly near However, even nonfatal jellyfish stings are known to be extremely painful. Serious stings may cause anaphylaxis and may result in death. Hence, people stung by jellyfish must get out of the water to avoid drowning. In serious cases, advanced professional care must be sought. This care may include administration of an antivenin and other supportive care such as required to treat the symptoms of anaphylactic shock. Antivenin (or antivenom or antivenene) is a biological product used in the treatment of venomous bites or stings

There are three goals of first aid for uncomplicated jellyfish stings: prevent injury to rescuers, inactivate the nematocysts, and remove any tentacles stuck on the patient. A cnidocyte, cnidoblast or nematocyte, is a type of Venomous cell unique to the Phylum Cnidaria ( Corals To prevent injury to rescuers, barrier clothing should be worn. This protection may include anything from panty hose to wet suits to full-body sting-proof suits. Inactivating the nematocysts, or stinging cells, prevents further injection of venom into the patient. This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation.

Vinegar (3 to 10% aqueous acetic acid) should be applied for box jellyfish stings. Vinegar is an acidic liquid processed from the Fermentation of Ethanol in a process that yields its key ingredient Acetic acid (also called ethanoic acid Acetic acid, also known as ethanoic acid, is an organic chemical compound, giving Vinegar its sour taste Box jellyfish are invertebrates belonging to the class Cubozoa, named for their Cube -shaped medusae. ^[6][7] Vinegar, however, is not recommended for Portuguese Man o' War stings. The Portuguese Man O' War ( Physalia physalis) also known as the blue bubble, blue bottle, man-of-war, or the Portuguese man of war ^[6] In the case of stings on or around the eyes, vinegar may be placed on a towel and dabbed around the eyes, but not in them. Salt water may also be used in case vinegar is not readily available. ^[6][8] Fresh water should not be used if the sting occurred in salt water, as a change in pH can cause the release of additional venom. pH is the measure of the acidity or alkalinity of a Solution. Rubbing the wound, or using alcohol, spirits, ammonia, or urine will encourage the release of venom and should be avoided. In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Urine is a liquid waste product of the body secreted by the Kidneys by a process of filtration from Blood and Excreted through the Urethra. ^[9] Though often not available, a shower or bath as hot as can be tolerated can neutralize stings. However, if hypothermia is suspected this method may cause other serious complications. Hypothermia is a condition in which an organism's temperature drops below that required for normal Metabolism and bodily functions

Once deactivated, the stinging cells must be removed. This can be accomplished by picking off tentacles left on the body. ^[9] First aid providers should be careful to use gloves or another readily available barrier device to prevent personal injury, and to follow standard universal precautions. Under Universal Precautions all patients are considered to be possible carriers of blood-borne pathogens After large pieces of the jellyfish are removed, shaving cream may be applied to the area and a knife edge, safety razor, or credit card may be used to take away any remaining nematocysts. A cnidocyte, cnidoblast or nematocyte, is a type of Venomous cell unique to the Phylum Cnidaria ( Corals ^[10]

Beyond initial first aid, antihistamines such as diphenhydramine (Benadryl) may be used to control skin irritation (pruritus). A histamine antagonist is an agent which serves to inhibit the release or action of Histamine. Pharmacological action Diphenhydramine (dye fen hye' dra meen works by blocking the effect of histamine at H1 receptor sites Benadryl is a brand name of McNeil Healthcare (UK Limited and is used to sell Hay fever treatments in various forms around the world Itch ( Latin: pruritus) is an unpleasant Sensation that evokes the desire or Reflex to scratch ^[10] To remove the venom in the skin, apply a paste of baking soda and water and apply a cloth covering on the sting. If possible, reapply paste every 15-20 minutes. Ice can be applied to stop the spread of venom until either of these is available.

See also

References

External links

• Cotylorhiza tuberculata
• Treatment of Coelenterate and Jellyfish Envenomations
• British Marine Life Study Society - Jellyfish Page
• Jellyfish - Curious creatures of the sea
• Sting treatment
• Jellyfish Grown with Twelve Heads
• Jellyfish Boom Driven Partly by Warming Waters

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