Jellyfish

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Jellyfish

Resources

Jellyfish, also called medusae, are free-swimming, marine invertebrates in the class Scyphozoa (phylum Cnidaria). They have a gelatinous, translucent, domeshaped body and occur most commonly in warm, tropical seas, although they are found in all the worlds oceans. Jellyfish feed on small planktonic animals or fish, which they sting and paralyze with special cells called nematocysts located on the tentacles that hang from the edge of their dome-shaped bodies. The body of a jellyfish is 99% water; when washed onto dry land, these animals die and rapidly disappear as the water in their body evaporates. The related class Cubozoa includes about 19 species of box jellyfish that are characterized by box-shaped, rather than dome-shaped, bodies.

About 200 species of true jellyfish are known, ranging in size from 0.06 in (1.5 mm) to 6.5 ft (2 m). All jellyfish have a prominent dome; the shape of the dome varies from a shallow saucer to a deep bell. Hanging from the edge of the dome are nematocyst-bearing tentacles; the number and length of these tentacles varies greatly from species to species. On the underside of the dome is a feeding tube (the manubrium or proboscis) with the animals mouth at its free end. Radial canals (usually four in number or some multiple of four) extend from the jellyfishs four-chambered stomach to the domes margin where they connect with the ring canal. This system of canals serves to distribute food to the outer parts of the jellyfishs body. Light-sensing organs (eyespots), balance organs (statocysts), and other sensory organs are located at the base of the tentacles. Jellyfish move through the water by pulsating contractions of the muscles on the lower edge of the dome.

Jellyfish release eggs and sperm through the mouth into the water, where fertilization occurs. Fertilization results in free-swimming, ciliated (with tiny, hair like structures) larvae called planulae; these larvae settle on a surface, such as a rock, and turn into a polyp (a hollow cylinder with tentacles and a mouth at one end) or a strobila (a hollow structure that looks like a stack of upside-down saucers). Strobila develop into adult jellyfish after passing through another freeswimming phase during which they are called ephyrula. Polyps produce adult jellyfish by budding. The

average life span of a jellyfish is one to three months; the largest may live for about one year.

The most common jellyfish on the coasts of North America and Europe is the moon jellyfish (Aurelia aurita ). This 68-in (15.220.2 cm) species is found at depths of 020 ft (06 m). It is whitish often shaded with pink or blue and has a saucer-shaped dome with a fringe of numerous, short tentacles around the margin. Its sting is mildly toxic to humans, occasionally producing an itchy rash. In the same order (Semaeostomeae) as the moon jellyfish is the giant pink jellyfish (Cyanea capillata ); this species is common in the waters of the Northern Hemisphere where it reaches about 6.5 ft (2 m) across.

The 31 species of deep-sea jellyfish (order Coronatae) are heavily pigmented in colors ranging from red and violet to brown and blackish. They are found at extreme depths; for example, Nausithoe has been found at a depth of 23,000 ft (7,100 m). The order Rhizostomeae includes about 80 species commonly known as many-mouthed jellyfish. In these species, the feeding tube has many small pores rather than one large opening. The genus Stromolophus of this order is common on the southeastern coast of the United States where it reaches a diameterof 7 in (18 cm).

The 19 species in the class Cubozoa live in the warm waters of the continental shelves. The largest species in this class, the sea wasp (Carybdea alata ), is found in tropical harbors and river mouths. It reaches a diameter of 9.75 in (25 cm) and sometimes eats fish much larger than itself. The sting of this and many other box jellyfish can be highly toxic producing a reaction in humans that may include skin welts, muscle cramps, and breathing difficulty. Two genera, Chiropsalmus and Chironex, found in the Indian Ocean produce a toxin so potent that contact with their nematocysts can kill a person within several minutes.

KEY TERMS

Nematocyst A stinging organ found in jellyfish. The animal uses it for defense and to paralyze its prey.

Planula A flat, ciliated free-swimming jellyfish larvae.

Other marine animals in the class Hydrozoa, order Siphonophora, superficially resemble true jellyfish and are often confused with them. The most well-known member of this order is the Portuguese man-of-war (Physalia physalis ). Each Portuguese man-of-war (so named because it resembles an eighteenth century warship) is a colony composed of four kinds of polyp. The main polyp is a gas-filled float that measures up to 12 in (30 cm) long. This float has a high crest which serves as a sail to catch the wind and its color varies from blue to purple to red. Hanging below the float in the water are other polyps; some of them are concerned with feeding while other are concerned with reproduction. Also below the float are trailing tentacles (up to 40 ft/12 m long) armed with nematocysts. The animal uses these tentacles to catch the fish and other sea creatures that it eats. The toxin produced by this species is also very potent; humans have been known to die from a Portuguese man-of-war sting. Usually when humans are stung, redness, skin welts, and blisters result. When washed ashore, this animal remains toxic for some time.

Resources

BOOKS

Cousteau, J. The Ocean World of Jacques Cousteau. Danbury, CT: Grolier, 1975.

Gowel, Elizabeth. Amazing Jellies: Jewels of the Sea. Piermont, NH: Bunker Hill Publishing, 2004.

Whiteman, Kate. World Encyclopedia of Fish and Shellfish. New York: Lorenz Books, 2000.

Christine B. Jeryan

Jellyfish

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Jellyfish

Pop group

Even though Jellyfish only recorded two albums, the group's critical acclaim and fervent fanbase have made them icons in the field of 1990s power-pop music. Carving out a niche with groups like Redd Kross and The Posies in the mid 1990s, these groups put a new spin on their favorite retro pop bands, creating an underground genre that remains popular among pop music fans. People's Eric Levin noted the band's talent: "…Jellyfish is a band driven by an ebullient love of pop and rock's whole gonzo arsenal of expression and a determination to craft every song into a fully loaded, to-the-max, minimasterpiece." Unfortunately, Jellyfish never reached beyond cult status and after only four years as a group, they parted ways. However, singer Andy Sturmer and keyboardist Roger Manning, the creative and songwriting force behind Jellyfish, along with guitarist Jason Falkner, went on to pursue satisfying solo careers.

In the late 1980s, friends Roger Manning and Andy Sturmer played in a funk-pop group called Beatnik Beach. After leaving the group to start a new one, Manning and Sturmer began to look for a bass player and a guitarist for a power-pop group they would eventually call Jellyfish. At the time, young guitarist Jason Falkner played with the band Three O'Clock, but after Falkner heard what Sturmer and Manning were working on, he dropped the group and joined Jellyfish along with bass player, and Roger's brother, Chris, to start this new and effervescent band. The sound emerging from rehearsals had a kitschy retro flavor that blended together colorful '60s psychedelic pop music with '70s power-pop. Signed to Virgin offshoot Charisma Records for 1990's Bellybutton, Jellyfish captured the retro vibe with help from Bee Gees's Saturday Night Fever producer Albhy Galuten.

Adorned in floppy hats and bellbottoms on the album cover, sugary treats, flowers, and bubbles all around them, there was no doubt that Jellyfish were going for a free love meets bubblegum ambiance. But their music was more intelligent than their campy photos let on. Their songs may have played homage to '60s and '70s pop heroes, but if you listened closely, there was something new and fresh going on. In an interview with the Los Angeles Times, Sturmer even admitted to their love of the '70s, as he stated, their "dream gig would be between Sweet and Badfinger."

Critics raved about Bellybutton, noting its Beatlesque styles. "Imagine McCartney at his most melodically ornate, but possessed of his onetime partner's cynical edges, and you've got Bellybutton, the greatest album Wings never made," Entertainment Weekly's Chris Willman wrote. The bouncy single "Baby's Coming Back" faired well on the Billboard charts and the album sent them off on a long tour across the United States, even playing with heroes Brian Wilson and Ringo Starr, the latter whom Sturmer and Manning collaborated with for an album (Starr's 1992 record Time Takes Time).

Reviews compared Sturmer and Manning to Lennon and McCartney of the Beatles and Jellyfish's love of the famous group could be heard all over Bellybutton, but after some time, the songwriting duo grew tired of the comparison. When they began to write songs for their sophomore album things would be different—but just slightly.

Before finishing songs for their second record however, both Chris Manning and Jason Falkner decided to quit the band. Falkner had wanted to begin a solo career before he had even joined Jellyfish and felt like now it was finally time to do so. Bassist Tim Smith joined the group full time and musicians Eric Dover, producer Jon Brion, and Lyle Workman became regular Jellyfish players and contributors to the band's 1993 record Spilt Milk.

Spilt Milk, produced by Sturmer and Manning along with Galuten, took Jellyfish's collective idols—the Beatles, the Beach Boys, ELO, and Queen, and rolled them into a rollicking, ambitious pop record. "On their second album … the band reached their peak," Keyboard magazine's Robbie Gennet wrote. "The production on this record is truly special, and listening in headphones better reveals the many subtle instrumentation and effects touches that are sprinkled liberally throughout."

Released in the middle of the grunge era, however, the lively and eclectic album failed to give the band a boost above the notice they had just begun to receive with Bellybutton. The record received glowing reviews from major magazines. Guitar Player even listed Spilt Milk in their list of the top 50 unsung albums that every guitarist should own. "This under-appreciated effort from pop-rock historians Jellyfish contains some of the best tunes that the Beatles, Badfinger, and the Beach Boys never wrote."

Though Bellybutton dented the Billboard charts, it was the beginning of the end for Jellyfish. In 1994, the band cited "creative differences" and disbanded Jellyfish. In the subsequent years, as Falkner released successful solo albums, Chris Manning and Sturmer became producers. Roger Manning and Eric Dover formed the power-pop group Imperial Drag and released one album before Roger Manning became a sought after session musician.

For the Record …

Members include Eric Dover (joined group, 1993), guitar; Jason Falkner (left group, 1993), guitar, bass, vocals; Chris Manning (left group, 1993), bass; Roger Manning , keyboards, vocals; Tim Smith (joined group, 1993), bass; Andy Sturmer , vocals, drums.

Group formed in San Francisco, CA, c. 1990; signed with Virgin Records imprint Charisma Records; released Bellybutton, 1990; members Jason Falkner and Chris Manning leave group, 1993; released sophomore and final album Spilt Milk, 1993; disbanded, 1994.

However, Jellyfish's underground legend in the pop world gained momentum as new bands began to cite the short-lived group as icons. In 1999, Charisma released Greatest, a 14-song collection of Jellyfish material that included some of the band's catchiest singles and even their takes on both a Wings and Badfinger song. 2002 saw the unexpected release of a Jellyfish box set titled Fan Club (a take on the band's song "Joining a Fan Club"). Released by Not Lame, the four-disc package assembled by the band and label contained the kind of material you wouldn't expect to find from a band that was only together for four years. The dozens of unreleased tracks only proved the devotion fans had retained to Jellyfish over the years.

Selected discography

Bellybutton, Charisma, 1990.

Spilt Milk, Charisma, 1993.

Greatest, Charisma, 1999.

Fan Club, Not Lame, 2002.

Sources

Books

Larkin, Colin, editor, The Encyclopedia of Popular Music, Macmillan, 1998.

Periodicals

Entertainment Weekly, May 17, 2002.

Guitar Player, April 2002, p. 88.

Keyboard, February 1, 2003, p. 18.

Los Angeles Times, October 25, 1990, p. 14.

People, April 26, 1993, p. 21.

Online

"Jellyfish," All Music Guide,http://www.allmusic.com (March 24, 2005).

ShannonMcCarthy

Jellyfish

views updated

Jellyfish

Jellyfish, also called medusae, are free-swimming, marine invertebrates in the class Scyphozoa (phylum Coelenterata). They have a gelatinous, translucent, dome-shaped body and occur most commonly in warm, tropical seas, although they are found in all the world's oceans. Jellyfish feed on small planktonic animals or fish which they sting and paralyze with special cells called nematocysts located on the tentacles that hang from the edge of their dome-shaped bodies. The body of a jellyfish is 99% water ; when washed onto dry land, these animals die and rapidly disappear as the water in their body evaporates.

About 200 species of true jellyfish are known, ranging in size from 0.06 in (1.5 mm) to 6.5 ft (2 m). All jellyfish have a prominent dome; the shape of the dome varies from a shallow saucer to a deep bell. In the subclass Cubomedusae, the dome is cube-shaped. Hanging from the edge of the dome are nematocyst-bearing tentacles; the number and length of these tentacles varies greatly from species to species. On the underside of the dome is a feeding tube (the manubrium or proboscis) with the animal's mouth at its free end. Radial canals (usually four in number or some multiple of four) extend from the jellyfish's four-chambered stomach to the dome's margin where they connect with the ring canal. This system of canals serves to distribute food to the outer parts of the jellyfish's body. Light-sensing organs (eyespots), balance organs (statocysts), and other sensory organs are located at the base of the tentacles. Jellyfish move through the water by pulsating contractions of the muscles on the lower edge of the dome.

Jellyfish release eggs and sperm through the mouth into the water, where fertilization occurs. Fertilization results in free-swimming, ciliated (with tiny, hair-like structures) larvae called planulae; these larvae settle on a surface, such as a rock, and turn into a polyp (a hollow cylinder with tentacles and a mouth at one end) or a strobila (a hollow structure that looks like a stack of upside-down saucers). Strobila develop into adult jellyfish after passing through another free-swimming phase during which they are called ephyrula. Polyps produce adult jellyfish by budding. The average life span of a jellyfish is one to three months; the largest may live for about one year.

The most common jellyfish on the coasts of North America and Europe is the moon jellyfish (Aurelia aurita). This 6–8-in (15.2-20.2 cm) species is found at depths of 0-20 ft (0-6 m). It is whitish, often shaded with pink or blue, and has a saucer-shaped dome with a fringe of numerous, short tentacles around the margin. Its sting is mildly toxic to humans, occasionally producing an itchy rash. In the same order (Semaeostomeae) as the moon jellyfish is the giant pink jellyfish (Cyanea capillata); this species is common in the waters of the Northern Hemisphere where it reaches about 6.5 ft (2 m) across.

The 16 species in the subclass Cubomedusae are commonly called box jellyfish; they live in the warm waters of the continental shelves. The largest species in this subclass, the sea wasp (Carybdea alata), is found in tropical harbors and river mouths. It reaches a diameter of 9.75 in (25 cm) and sometimes eats fish much larger than itself. The sting of this and many other box jellyfish can be highly toxic producing a reaction in humans that may include skin welts, muscle cramps, and breathing difficulty. Two genera, Chiropsalmus and Chironex, found in the Indian Ocean produce a toxin so potent that contact with their nematocysts can kill a person within several minutes.

The 31 species of deep-sea jellyfish (order Coronatae) are heavily pigmented in colors ranging from red and violet to brown and blackish. They are found at extreme depths; for example, Nausithoe has been found at a depth of 23,000 ft (7,100 m). The order Rhizostomeae includes about 80 species commonly known as many-mouthed jellyfish. In these species, the feeding tube has many small pores rather than one large opening. The genus Stromolophus of this order is common on the southeastern coast of the United States where it reaches a diameter of 7 in (18 cm).

Other marine animals in the class Hydrozoa , order Siphonophora, superficially resemble true jellyfish and are often confused with them. The most well-known member of this order is the Portuguese man-of-war (Physalia physalis). Each Portuguese man-of-war (so named because it resembles an eighteenth century warship) is a colony composed of four kinds of polyp. The main polyp is a gas-filled float that measures up to 12 in (30 cm) long. This float has a high crest which serves as a sail to catch the wind and its color varies from blue to purple to red. Hanging below the float in the water are other polyps; some of them are concerned with feeding while other are concerned with reproduction. Also below the float are trailing tentacles (up to 40 ft/12 m long) armed with nematocysts. The animal uses these tentacles to catch the fish and other sea creatures that it eats. The toxin produced by this species is also very potent; humans have been known to die from a Portuguese manof-war sting. Usually when humans are stung, redness, skin welts, and blisters result. When washed ashore, this animal remains toxic for some time .


Resources

books

Cousteau, J. The Ocean World of Jacques Cousteau. Danbury, CT: Grolier, 1975.

Whiteman, Kate. World Encyclopedia of Fish & Shellfish. New York: Lorenz Books, 2000.


Christine B. Jeryan

KEY TERMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nematocyst

—A stinging organ found in jellyfish. The animal uses it for defense and to paralyze its prey.

Planula

—A flat, ciliated free-swimming jellyfish larvae.

Scyphozoa

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Scyphozoa (jellyfish; phylum Cnidaria) A class of marine, mainly pelagic medusoids (see MEDUSA) which differ from the class Hydrozoa in possessing endodermal gastric tentacles, four-part radial symmetry, and gonads located in the gastric cavity. The polyp stage is reduced or absent.

Scyphozoa

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Scyphozoa (jellyfish; phylum Cnidaria) Class of marine, mainly pelagic medusoids, usually with four-part radial symmetry, in which the polyp stage is reduced or absent. Their fossil record is in general scanty, owing to the absence of hard parts, but jellyfish formed an important component of the Precambrian Ediacaran fauna. See also MEDUSINA MAWSONI.

jellyfish

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jel·ly·fish / ˈjelēˌfish/ • n. (pl. same or -fishes) a free-swimming marine coelenterate (classes Scyphozoa and Cubozoa) with a jellylike bell- or saucer-shaped body that is typically transparent and has stinging tentacles around the edge.

jellyfish

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jellyfish Marine coelenterate found in coastal waters and characterized by tentacles with stinging cells. The adult form is the medusa. It has a bell-shaped body with a thick layer of jelly-like substance between two body cell layers, many tentacles and four mouth lobes surrounding the gut opening. Diameter: 7.5–30.5cm (3in–12in). Class Scyphozoa.

jellyfish

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jellyfish See SCYPHOZOA.

jellyfish

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jellyfish See Cnidaria.

Scyphozoa

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Scyphozoa See Cnidaria.