Full Answer
Are jellyfish really a fish?
Unlike their name suggest, jellyfish are not really fish as they lack a backbone. In fact, these animals are actually invertebrates and they are more closely related to corals, sea anemones, and sea whips than fish.
Why do jellyfish sting humans?
What causes jellyfish stings? People may come into contact with the nematocysts of a jellyfish when they are swimming in the ocean or walking on the beach. This contact can cause the venom from the nematocysts to be injected into the body. More than 150 million jellyfish stings happen in the world each year.
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!
Do jellyfish sting each other jellyfish?
There are some larger Jellyfish that prey on smaller ones, these may sting the smaller ones, but generally they are not turn on each other. A number of Jellyfishes travel in schools and hence it is safe to say that they do not sting each other.
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 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 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 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 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 are Jellyfish called Fish?
In the past, people started to call most of the animals living in water as fishes including Jellyfish even though Jellyfish is not actual fish since they do not possess backbones , and fins like fish but have amazing characters that even absent in fishes (for example stinging cells) so Jellyfish is classified as a different category rather than fishes. However, we refer to the Jellyfish as fish till today.
What is a Jellyfish classified as?
Jellyfish also called aurelia classified as coelenterates meaning stinging animals. These are special creatures evolved in water 50 crore years ago, One of the oldest multicellular organisms in the world. Sizing from ant-size to more than a human-size exclusively marine with a soft body containing approximately 95% of water.
What are the characteristics of a Jellyfish?
Aurelia or Jellyfish are also found in coastal water of the tropical and temperate seas. These are marine creatures.
What do Jellyfish Eat?
Food of a Jellyfish includes small zooplankton, fish, fish eggs, Larvae. They have only one mouth for food intake also to excrete it out of the body.
How long do Jellyfish live in a tank?
The average life expectancy of Jellyfish depends on the natural or artificial climate of the environment they live in and also depends on the type of Jellyfish you choose as pets, but the lifespan of Moon Jellyfish (Aurelia Aurita) is around 1 to 2 years, while Blue blubber jellies can live for 12 to 15 months and surprisingly the Sea Nettles can thrive for several years, only if they are taken care appropriately in the artificial setup.
What is the phylum of jellyfish?
Scientists put jellyfish-like organisms in a group (phylum) called “Cnidaria.” (The “c” is silent). The Cnidaria category contains and classifies organisms that have stinging cells called nematocysts. Underneath Cnidaria are several sub-categories (Classes):
What is a jelly with a lot of tissue called?
Scyphozoa – includes “true jellies” which have a lot of gelatinous tissue called “mesoglea.” Example: moon jelly (Aurelia) and cannonball jelly (Stomolophus).
What do John and Sally search for in the internet cafe?
They’ll type in search terms like “florida jellyfish,” “purple jellyfish,” “jellyfish with purple tentacles,” etc. They will not search for “siphonophore” or “man-of-war” or “hydrozoa” since they’ve never heard of those terms.
Is box jelly a jellyfish?
You might have noticed that the infamous and sometimes deadly box jelly is not a true jellyfish either as it is a Cubozoan. Nevertheless it too is commonly referred to as a jellyfish.
What is a Jellyfish?
Jellyfish are the medusa phase of certain animals in the phylum Cnidaria. This phylum includes a unique assortment along with corals and sea anemones
What phylum is jellyfish in?
Jellyfish are the medusa phase of certain animals in the phylum Cnidaria. This phylum includes a unique assortment along with corals and sea anemones. If you observe sea anemones closely, they look like upside-down jellyfish. This is because in the phylum Cnidaria, not all animal species in their sedentary phase (called the polyp phase) ...
How do jellyfish reproduce?
Jellyfish can reproduce asexually by budding in their polyp stage. In fact, a jellyfish can produce more polyps by asexual reproduction than it can create planula as a medusa. Jellyfish also reproduce sexually during the medusa stage by releasing sperm and eggs into the water, creating new planula in the process.
Why is a jellyfish immortal?
A jellyfish species called Turritopsis dohrnii can be immortal because it has the ability to become a polyp once again after reaching the medusa phase. Though this behavior only been seen in labs, the Turritopsis dohrnii can teach scientists about age reversal. 2. One Jellyfish Is the Most Lethal Marine Organism.
Why are jellyfish so fun?
Jellyfish are fun to watch because they are so unique looking with long tentacles and different kinds of movement. But they look completely different from most other animals with the word fish in their name. Is a jellyfish a fish? Jellyfish are not actual fish despite their name.
What is the sexual phase of jellyfish?
This free-swimming phase is called the medusa phase. The medusa phase is also the sexual phase for jellyfish. They release sperm and eggs into the water. When an egg becomes fertilized, it becomes a planula and the lifecycle repeats.
How long have jellyfish been around?
Jellyfish fossils dating back to more than 500 million years ago have been found, making them the oldest fossils on record (so far). This means that jellyfishes have been on Earth much longer than most animals, and they predate the dinosaurs.
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 interchangeabl…
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 us…