What are facts about jellyfish?
Quick Facts
- Type: Medusa/Non-Polyp
- Diet: Carnivore
- Life span: 2-6 months - 30 years. ...
- Size: From 1mm wide to 1.8m wide & 15m long depending on the species
- Weight: From 5 pounds to 450 pounds depending on the species
- Habitat: Saltwater habitats but some can be found in freshwater
- Range: Across the world
- Scientific Name: Medusozoa
What type of symmetry do cnidarians have?
What type of symmetry do cnidarians have? radial symmetry The two body forms of cnidarians are _________ , a tube-shaped mouth surrounded by tentacles, and ___________ , an umbrella shape in which the tentacles hang down.
What are characteristics of jellyfish?
What are the characteristics of a jellyfish? Jellyfish have no brain, heart, bones or eyes. They are made up of a smooth, bag-like body and tentacles armed with tiny, stinging cells. These incredible invertebrates use their stinging tentacles to stun or paralyse prey before gobbling it up. The jellyfish's mouth is found in the centre of its body.
What is a good name for a jellyfish?
- Peanut — The average size of a Moon Jelly is only 2 to 15 inches.
- Pearl — For your equally precious pet jelly.
- Pixie
- Gus — A cute name for any tiny pet.
- Penny — Jellyfish are expensive pets, so you might have to spend more than a penny on these guys!
- Cookie
- Coco
- Teeny Tiny — This one is for all the pet owners who love a rhyme!
What is the name of the jellyfish?
The name jellyfish, in use since 1796, has traditionally been applied to medusae and all similar animals including the comb jellies ( ctenophores, another phylum). The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its modern connotation of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either. In scientific literature, "jelly" and "jellyfish" have been used interchangeably. Many sources refer to only scyphozoans as "true jellyfish".
How are box jellyfish similar to hydrozoans?
A short pedalium or stalk hangs from each of the four lower corners. One or more long, slender tentacles are attached to each pedalium. The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when the bell pulsates, allowing box jellyfish to swim faster than true jellyfish. Hydrozoans are also similar, usually with just four tentacles at the edge of the bell, although many hydrozoans are colonial and may not have a free-living medusal stage. In some species, a non-detachable bud known as a gonophore is formed that contains a gonad but is missing many other medusal features such as tentacles and rhopalia. Stalked jellyfish are attached to a solid surface by a basal disk, and resemble a polyp, the oral end of which has partially developed into a medusa with tentacle-bearing lobes and a central manubrium with four-sided mouth.
What are the different types of cnidaria?
The four major classes of medusozoan Cnidaria are: 1 Scyphozoa are sometimes called true jellyfish, though they are no more truly jellyfish than the others listed here. They have tetra-radial symmetry. Most have tentacles around the outer margin of the bowl-shaped bell, and long, oral arms around the mouth in the center of the subumbrella. 2 Cubozoa (box jellyfish) have a (rounded) box-shaped bell, and their velarium assists them to swim more quickly. Box jellyfish may be related more closely to scyphozoan jellyfish than either are to the Hydrozoa. 3 Hydrozoa medusae also have tetra-radial symmetry, nearly always have a velum (diaphragm used in swimming) attached just inside the bell margin, do not have oral arms, but a much smaller central stalk-like structure, the manubrium, with terminal mouth opening, and are distinguished by the absence of cells in the mesoglea. Hydrozoa show great diversity of lifestyle; some species maintain the polyp form for their entire life and do not form medusae at all (such as Hydra, which is hence not considered a jellyfish), and a few are entirely medusal and have no polyp form. 4 Staurozoa (stalked jellyfish) are characterized by a medusa form that is generally sessile, oriented upside down and with a stalk emerging from the apex of the "calyx" (bell), which attaches to the substrate. At least some Staurozoa also have a polyp form that alternates with the medusoid portion of the life cycle. Until recently, Staurozoa were classified within the Scyphozoa.
Why do box jellyfish have a faster pupillary contraction rate?
Behavioral studies suggest that faster pupil contraction rates allow for greater object avoidance, and in fact, species with more complex habitats exhibit faster rates. Ch. bronzie inhabit shallow beach fronts that have low visibility and very few obstacles, thus, faster pupil contraction in response to objects in their environment is not important. Ca. barnesi and Ch. fleckeri are found in more three dimensionally complex environments like mangroves with an abundance of natural obstacles, where faster pupil contraction is more adaptive. Behavioral studies support the idea that faster pupillary contraction rates assist with obstacle avoidance as well as depth adjustments in response to differing light intensities.
Why are jellyfish harvested?
Jellyfish are also harvested for their collagen, which is being investigated for use in a variety of applications including the treatment of rheumatoid arthritis.
How long have jellyfish been around?
Jellyfish have been in existence for at least 500 million years, and possibly 700 million years or more, making them the oldest multi-organ animal group. Jellyfish are eaten by humans in certain cultures.
What is the name of the sea jellies?
Play media. Spotted jellies swimming in a Tokyo aquarium. Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, ...
Why is symmetrical jellyfish important?
The scientists had stumbled upon a phenomenon completely new to science, which they call "symmetrization.". Because jellyfish often suffer from injuries—sometimes inflicted by unsuccessful predators—symmetri zation is an important method to heal themselves .
How long does it take for a moon jellyfish to restore symmetry?
Moon jellyfish (pictured at the Vancouver Aquarium) can restore their symmetry within four days.
How many arms does a moon jellyfish have?
Instead, the moon jelly had rearranged its six remaining arms until they were evenly placed around the body. Muscles in the jellyfish's body had pushed and pulled on the remaining arms until they were once again evenly spaced. Being symmetrical is crucial for moon jellyfish movement.
Why did Abrams repeat the jellyfish experiments?
After observing the jellyfish putting themselves back together, "I repeated the experiments several times because I thought I might have made a mistake ," Abrams says. (See jellyfish pictures from the National Geographic archives .)
Why do jellyfish lose limbs?
A jellyfish can lose a limb due to predators. Moon jellyfish (pictured, animals from the Toledo Zoo) are common in the world's oceans.
How long does it take for a jellyfish to reorganize its arms?
Once he had reassured himself that the jellyfish really was rearranging its arms to restore symmetry—a process which takes between 12 hours to 4 days —Abrams and his team had to figure out how the animal manages such a feat. After several false starts, the researchers focused on the jellyfish's musculature.
Where are moon jellyfish found?
Moon jellyfish (pictured, animals from the Toledo Zoo) are common in the world's oceans.
Overview
Mapping to taxonomic groups
The term jellyfish broadly corresponds to medusae, that is, a life-cycle stage in the Medusozoa. The American evolutionary biologist Paulyn Cartwright gives the following general definition:
Typically, medusozoan cnidarians have a pelagic, predatory jellyfish stage in their life cycle; staurozoans are the exceptions [as they are stalked].
Names
The name jellyfish, in use since 1796, has traditionally been applied to medusae and all similar animals including the comb jellies (ctenophores, another phylum). The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its modern connotation of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either. In scientific literature, "jelly" and "jellyfish" have been used interchange…
Anatomy
The main feature of a true jellyfish is the umbrella-shaped bell. This is a hollow structure consisting of a mass of transparent jelly-like matter known as mesoglea, which forms the hydrostatic skeleton of the animal. 95% or more of the mesogloea consists of water, but it also contains collagen and other fibrous proteins, as well as wandering amoebocytes which can engulf debris and bacteria. The mesogloea is bordered by the epidermis on the outside and the gastrode…
Largest and smallest
Jellyfish range from about one millimeter in bell height and diameter, to nearly 2 metres (6+1⁄2 ft) in bell height and diameter; the tentacles and mouth parts usually extend beyond this bell dimension.
The smallest jellyfish are the peculiar creeping jellyfish in the genera Staurocladia and Eleutheria, which have bell disks from 0.5 millimetres (1⁄32 i…
Life history and behavior
Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae. In some species certain stages may be skipped.
Ecology
Jellyfish are like other cnidarians generally carnivorous (or parasitic), feeding on planktonic organisms, crustaceans, small fish, fish eggs and larvae, and other jellyfish, ingesting food and voiding undigested waste through the mouth. They hunt passively using their tentacles as drift lines, or sink through the water with their tentacles spread widely; the tentacles, which contain nematocysts to stu…
Relation to humans
Jellyfish have long been eaten in some parts of the world. Fisheries have begun harvesting the American cannonball jellyfish, Stomolophus meleagris, along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asia.
Jellyfish are also harvested for their collagen, which is being investigated for u…