The body of the jellyfish is shaped like a transparent umbrella, and the diameter of the umbrella varies from large to small, with the diameter of the umbrella of a large jellyfish reaching up to 2 meters. From the edge of the umbrella body to grow some baleen-like strips, this strip is called tentacles, some tentacles can be as long as 20 meters to 30 meters, equivalent to the length of a large whale. Jellyfish floating in the water, stretching out long tentacles in all directions, some jellyfish umbrella body also has a variety of color patterns. In the blue ocean, these swimming jellyfish with different colors look very beautiful. Jellyfish predate the dinosaurs, dating back 650 million years. There are many species of jellyfish, about 250 species around the world, with diameters ranging from 10 centimeters to 100 centimeters, which are commonly found in the oceans all over the world. There are about eight common species in China, namely, the sea moon jellyfish, white haze jellyfish, jellyfish, and mouth-crowned jellyfish. People often classify them according to the difference of their umbrellas: some umbrellas glow silver and are called silver jellyfish; some umbrellas look like monks' hats and are called monk's hat jellyfish; some umbrellas look like white sails on a ship and are called sail jellies; some look like umbrellas and are called umbrella jellyfish; and some umbrellas are shining with the light of colorful sunshine and are called haze jellyfish ... ...Most of them live only a few weeks, but some live up to a year or so, and some deep-sea jellyfish can live even longer. Ordinary jellyfish umbrella is not very large, only 20 to 30 centimeters long, but the larger size of the giant umbrella of the summer jellyfish can be up to 2 meters in diameter, the drooping tentacles up to 20 to 30 m. In 1865, in the United States, Massachusetts coast, there is a summer jellyfish by the waves washed up on the shore, its umbrella diameter of 2.28 meters, tentacle length of 36 m. The umbrella was pulled out of the sea, and the tentacle was pulled out of the sea, and the tentacle was pulled out of the sea. Pull the tentacles of this jellyfish, from the tip of a tentacle to the tip of another tentacle, there are 74 meters long. Therefore, it can be said that jellyfish is the world's longest animal. There are about 250 species of jellyfish around the world, ranging from 10 centimeters to 100 centimeters in diameter, and are commonly found in oceans everywhere.
Species of the scyphozoan jellyfish order are free-swimming and are found in all oceans, including the common discoids that drift along coastlines. Most live only a few weeks, and some live about 1 year. The diameter is generally 2?6?540 centimeters (1?6?516 inches), but some species are quite large, up to 2 meters (6.6 feet) in diameter. The body composition is 99% water, as the main body of almost every species consists of a gelatinous substance. Most prey on small animals with tentacles that have stinging filamentous cells. Some species filter feed on microscopic animals and plants in the water. Like all cnidarians, the body consists of two germ layers, the inner and outer, between which there is a gelatinous layer (a layer of nodular tissue composed of gelatinous material). Jellyfish have a thicker mesoglossal layer than other cnidarians, are floating and transparent.
The life history of the free-swimming true jellyfish can be divided into three phases. The solid hydroid body can camp asexual reproduction, from the upper end of the downward transverse split into mantle mouth larvae, then split into saucers, each saucer grows into an adult. Adults are male and female, but some species often change sex. In many species, the embryonic bodies formed after the sperm-egg union hatch into floating wave larvae in the digestive tract of the adult, but some develop in seawater. After leaving the parent, the larvae fixate and grow into a new mantle larva after a short period of time in the so-called hydra tube larval stage. Such a life history is unique to the order Semaeostomeae, which consists of about 50 species, mainly in the littoral zone, some of which are extremely widespread. Examples include the sea-moon jellyfish genus Aurelia, the golden jellyfish genus Chrysaora, and the great red jellyfish Tiburonia granrojo (in the subfamily Tiburoniinae), the latter of which is one of the three species of tentacleless jellyfish.
There are about 30 species in the order Coronatae, most of which are found in the deep sea and are often maroon in color. The body is bell-shaped, bounded by a deep ring-shaped groove between the middle of the carapace and the peripheral part, and the peripheral part is divided into many broad flaps. The marginal tentacles are large and solid. Several species have a mantle-mouth larval stage, but the life history of most species is unknown. The crown jellyfish is the most primitive mantle jellyfish in existence and is probably descended from the cone jellyfish. Cone jellies flourished between 180 million and 600 million years ago, but only fossils remain today. Several species of crown jellies have persistent branching groups and were once organized into a single genus (Stephanoscyphus).
There are about 80 species in the order Rhizostomeae. The oral carpus is a fold-like protuberance formed by reaching down from the lower part of the body, which heals into a root-like shape, blocking the mouth and forming a spongy area for filtering food. Unciliated tentacles. Gelatinous bell-shaped body firm and tuberculate. Life history known to have a typical benthic mantle-mouth larval stage. Most species of this order are good swimmers; however, some (e.g., Cassiopea) swim infrequently, and are found in shallow tropical waters, where they provide light for the photosynthesizing algae with which they ****. The species of this order mainly live in the Indo-Pacific Ocean in the tropical to subtropical shallow sea, but the root mouth jellyfish genus (Rhizostoma, also known as soccer ball jellyfish), common in the cooler sea; cup root jellyfish genus (Cotylorhiza) common in the Mediterranean Sea.
The order Cruciformes (formerly Lucernariida) is not strictly speaking true jellyfish, with about 30 species that are stalked and live solidly. Lives mainly in cold water. Wineglass-shaped, with a basal stalk fixed, mouth located at the upper end. Diameter 1?6?510 centimeters (0.4?6?54 inches). The upper margin has eight sets of tentacles in a quadradial shape. Some species are able to dislodge the fixation point and can fixate again. Often prey on small marine animals and live for several years. Develops directly from larva to adult. The hydrozoan stage is inconspicuous.
There is only one order of Cubomedusae, the Cubomedusae, which some biologists still classify as mantle jellyfish. About 50 species are known. Although some species are up to 25 centimeters (10 inches) in diameter, most are 2?6?54 centimeters (1?6?52 inches) in diameter; the body is spherical, but the sides are square, hence the common name box jellyfish. Chironex and Chiropsalmus, commonly known as sea wasps, are widely distributed from Queensland northward to near Malaya, and are both highly venomous, causing death within minutes of stinging. The hydrozoa of the cuban jellyfish have not been seen to reproduce by budding, but metamorphose into adults.
The main component of the jellyfish body is water, and by the inner and outer two embryonic layers, there is a thick layer of gelatinous layer between the two layers, not only transparent, but also has a floating effect. They are in motion, the use of the body of the water jet reflex forward, from a distance, as if a round umbrella in the water quickly floating. When the jellyfish in the sea swarms, live closely together as a whole like a deep floating on the sea surface, looks very spectacular. The waves are like snow, and the blue sea is dotted with many graceful umbrellas, shining with a faint pale green or blue-violet glow, some with a rainbow-like halo. Many jellyfish glow. The slender tentacles stretch out in all directions, drifting along with them in a beautiful display of color and swimming. Jellyfish have a special gland inside their umbrella that emits carbon monoxide, which causes the umbrella to expand. When a jellyfish encounters an enemy or is caught in a big storm, it will automatically release the gas and sink to the bottom of the sea. Once the sea is calm, it only takes a few minutes for it to produce the gas to inflate itself and float. When the ctenophore swims in the sea, the eight meridian tubes can emit blue light, and when it glows, the ctenophore becomes a glorious ball of color; around and in the middle part of the banded jellyfish, there are several parallel bands of light, and when it swims, the bands of light sway with the waves, which is very beautiful. Jellyfish rely on a wonderful protein called Equimine, which emits a strong blue light when mixed with calcium ions. The more of it there is in the jellyfish, the stronger the light will be, and each jellyfish contains an average of only 50 micrograms of the substance.
The jellyfish, though beautiful and docile, are actually very fierce. Underneath the umbrella-like body, those slender tentacles are its digestive organs and also its weapons. On top of the tentacles are covered with stinging cells, like venomous filaments, capable of shooting venom, after the prey is stung, it will quickly paralyze and die. The tentacles then grab these prey tightly, shrink back, and suck them in with the polyps under the umbrella body, each of which is able to secrete enzymes that rapidly break down the proteins in the prey. Because jellyfish do not have respiratory organs and circulatory systems, but only primitive digestive organs, the captured food is immediately digested and absorbed in the cavernous intestine. In the hot summer, when we swim in the sea tide, sometimes will suddenly feel the body of the chest, back or limbs of a burst of stinging pain, as if by the whip feeling, it is likely to be a jellyfish in the strange sting. However, generally stung by jellyfish, only feel the pain and red swelling, as long as the application of anti-inflammatory drugs or vinegar, after a few days that will be able to reduce the swelling and pain. However, in the sea from Malaysia to Australia, there are two kinds of jellyfish called sea wasp jellyfish (box jellyfish) and trailing hand jellyfish, which secrete toxicity is so strong that if you are stung by them, you will die of respiratory distress within a few minutes, so they are also known as killer jellyfish. Therefore, when stung by a jellyfish and breathing difficulty occurs, artificial respiration should be carried out immediately or cardiotonic injection should be given, and no carelessness should be exercised to avoid accidents. Once a jellyfish meets its prey, it never lets go easily. But just like the rhinoceros and the little bird that ****survives for it to clean up its parasites, the jellyfish has its own ****surviving partner. It's a small shepherd fish, no more than 7 centimeters long, that can swim between the jellyfish's tentacles as it pleases without being afraid at all. When a big fish swims, the little shepherd fish swims to the giant umbrella under the tentacles, as a safe "shelter", using the jellyfish stinging cell device, cleverly avoided the enemy's attack. Sometimes, the little shepherd fish can even lure the big fish into the hunting range of the jellyfish and kill them, so that they can also eat the leftover scraps of the jellyfish. So why don't the stinging cells on the jellyfish's tentacles hurt the Little Mako? This is because the small Shepherdfish is flexible and can skillfully avoid the poisonous filaments and is not easily harmed, but only occasionally there are inadvertent deaths under the poisonous filaments. The jellyfish and the little mako **** born together, each other for the use of the jellyfish "protect" the little mako, and the little mako swallowed the jellyfish body habitat of small organisms.
Mighty and deadly jellyfish also have natural enemies, a kind of sea turtle can be in the jellyfish group free shuttle, easily with the mouth to tear off their tentacles, so that it can only roll up and down, and finally lost the ability to resist, become the turtle's meal.
Jellyfish tentacles in the middle of the thin handle on a small ball, there is a small grain of hearing stone, which is the jellyfish's "ears". By the waves and air friction and produce infrasound impact hearing stone, stimulate the surrounding nerve receptors, so that the jellyfish in the storm before the arrival of more than ten hours will be able to get the information, so they are as if they received the order, from the surface of the sea all of a sudden disappeared. Scientists have experimented with simulating the jellyfish's acoustic transmitter organs and found that they can detect ocean storms up to 15 hours in advance.
Jellyfish are envied for having three generations of jellyfish, even though they are lowly coelenterates. Jellyfish give birth to baby jellyfish, which are able to survive on their own, but the bond between parent and child seems so strong that they can't bear to be separated, so the baby jellyfish cling to the jellyfish's body. Soon after, the small jellyfish gave birth to grandchildren jellyfish, still closely linked together.