Jellyfish

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Stauromedusae Coronatae Semaeostomeae Rhizostomae

Jellyfish (also known as jellies or sea jellies) are free-swimming members of the phylum Cnidaria. They have several different morphologies that represent several different cnidarian classes including the Scyphozoa (over 200 species), Staurozoa (about 50 species), Cubozoa (about 20 species), and Hydrozoa (about 1000-1500 species that make jellyfish and many more that do not). The jellyfish in these groups are also called, respectively, scyphomedusae, stauromedusae, cubomedusae, and hydromedusae; medusa is another word for jellyfish. (Medusa is also the word for jellyfish in Modern Greek, Finnish, Portuguese, Romanian, Hebrew, Serbian, Croatian, Spanish, Italian, Hungarian, Polish, Lithuanian, Czech, Slovak, Russian, Bulgarian and Catalan).[citation needed]

Jellyfish are found in every ocean, from the surface to the deep sea.[citation needed] Some hydrozoan jellyfish, or hydromedusae, are also found in fresh water and are less than half an inch in size. They are partially white and clear and do not sting. This article focuses on scyphomedusae. These are the large, often colorful, jellyfish that are common in coastal zones worldwide.

In its broadest sense, the term jellyfish also generally refers to members of the phylum Ctenophora. Although not closely related to cnidarian jellyfish, ctenophores are also free-swimming planktonic carnivores, are generally transparent or translucent, and exist in shallow to deep portions of all the world's oceans.

For more information about Jellyfish, read the full article at Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.

News tagged with jellyfish

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Aquatic creatures mix ocean water

Physics / General Physics

Nov 22, 2009 | 5 / 5 (4) | 1

Understanding mixing in the ocean is of fundamental importance to modeling climate change or predicting the effects of an El Niño on our weather. Modern ocean models primarily incorporate the effects of winds and tides. However, ...

Scientists Unravel Evolution of Highly Toxic Box Jellyfish

Biology / Plants & Animals

Nov 18, 2009 | 4 / 5 (4) | 1

(PhysOrg.com) -- With thousands of stinging cells that can emit deadly venom from tentacles that can reach ten feet in length, the 50 or so species of box jellyfish have long been of interest to scientists ...

Red Sea coral seen to feed on jellyfish

Biology / Plants & Animals

Nov 17, 2009 | 4.5 / 5 (12) | 2

(PhysOrg.com) -- Corals depends on the products of photosynthetic algae for most of their food, but they also eat tiny plankton. Now, for the first time, there is evidence of a coral eating jellyfish.

Jellyfish swarm northward in warming world

Biology / Ecology

Nov 15, 2009 | 4.3 / 5 (15) | 1

(AP) -- A blood-orange blob the size of a small refrigerator emerged from the dark waters, its venomous tentacles trapped in a fishing net. Within minutes, hundreds more were being hauled up, a pulsating ...

Will a well-mixed, warmer lake doom invasive fish?

Space & Earth / Environment

Jul 30, 2009 | 4 / 5 (2) | 2

(PhysOrg.com) -- The rainbow smelt, an invasive fish that threatens native species such as walleye and perch, may soon be feeling the heat -- literally.

Caltech researchers link tiny sea creatures to large-scale ocean mixing

150 years later, Darwin vindicated... by jellyfish: Researchers link tiny sea creatures to large-scale ocean mixing

Space & Earth / Earth Sciences

Jul 29, 2009 | 4.6 / 5 (21) | 10

(PhysOrg.com) -- Creatures large and small may play an important role in the stirring of ocean waters, according to a study released Wednesday that confirms a theory advanced by Charles Darwin.

Jellyfish Robot Swims Like its Biological Counterpart

Electronics / Robotics

Jun 26, 2009 | 4.4 / 5 (9) | 1

(PhysOrg.com) -- "Jellyfish are one of the most awesome marine animals, doing a spectacular and psychedelic dance in water," explain engineers Sung-Weon Yeom and Il-Kwon Oh from Chonnam National University ...

Jellyfish joyride a threat to the oceans

Biology / Ecology

Jun 08, 2009 | 3.9 / 5 (7) | 3

Early action could be crucial to addressing the problem of major increases in jellyfish numbers, which appears to be the result of human activities.

Jellyfish: Far from Passive Drifters-in-the-Currents

Biology / Plants & Animals

May 11, 2009 | 5 / 5 (2) | 0

(PhysOrg.com) -- If you were to snorkel just before dawn at the popular tropical Pacific destination Jellyfish Lake, you'd have lots of company: millions of golden jellyfish, known to scientists as Mastigias ...

Early family ties: No sponge in the human family tree

Biology / Evolution

Apr 02, 2009 | 4.8 / 5 (6) | 0

Since the days of Charles Darwin, researchers are interested in reconstructing the "Tree of Life", and in understanding the development of animal and plant species during their evolutionary history. In the case of vertebrates, ...