Most jellyfish eat plankton, crustaceans and fish
Jellyfish are a fascinating species whose body consists of 95 to 98 percent water. A jellyfish has no brain, no head, no heart and no digestive system. Since they can only move horizontally, they depend in search of food on the tides, the wind and the sea currents. But her rudimentary nervous system makes them sensitive to light, odor, pressure and other external stimuli react, so they begin abundant prey without needing any intervention.
Scyphozoa and box jellyfish are carnivorous
- In the North Sea and the Baltic Sea jellyfish (Aurelia aurita) are predominantly located. The designation goes back to four rings which are seen in the center of the screen. In the tentacles of this scyphozoa sensory cells are found that allow these cnidarians, perceive light and potential food. Based in Germany Aurelia aurita feeds mainly on small crabs, plankton and water fleas.
- The types of class "box jellyfish" distinguished not only by its cube-like form, they are also built more complex than scyphozoa. The class of the Australian box jellyfish include inter alia the dreaded sea wasp (Chiropsalmus quadrigatus) whose nettle poison for humans is fatal. Their tentacles, on which more than five billion stinging cells may be located, reach a length of up to three meters. Since this box jellyfish is not a hunter, you benefit from the long tentacles. The food of the box jellyfish consists mainly of crustaceans and small fish, which advised them more or less randomly between the tentacles.
Agent nematocysts and tentacles caught the food of jellyfish
Some jellyfish hunt their prey active afterwards, others are passive and wait for the food to come to them. In both cases, the tentacles are used.
- These involve millions of nematocysts. Stinging cells are tiny, poison-containing capsules. Each cnidocyte is equipped with a highly sensitive eyelash that works as a detector. At the slightest touch shoots a harpoon from the capsule, drilled through the surface of the loot and sets the poison-free. The venom of the jellyfish immediately goes into the bloodstream and paralyzes or kills the victim.
- Does the food at the sticky tentacles jellyfish pushes the feed, with the mouth arms, in her mouth, which can be found below the screen. Behind the mouth, in the middle of jellyfish screen, there is a pocket, are produced in the gastric juices. Here, the food is processed. The food, which can not digest the jellyfish is conveyed through the mouth out again.
Zooplankton, the food of the polyps
Polyps produce jellyfish, which are to jellyfish. the female germ cells of jellyfish have been fertilized, arise larvae that drift in the water and eventually hanging on a rock.
- From the larvae develop polyps. These are tiny organisms in the order of two to three millimeters. Visually, one could compare the polyp using a tube to a central mouth is in the middle. The upper edge is surrounded by many small tentacles resemble the long lashes.
- With the tentacles catch the polyps zooplankton, which serves them as food. After some time, the upper body of the polyp is divided into many annular segments, which may be produced ultimately. These rings are new jellyfish. They will carry their jellyfish life continued as genetically identical clones and eat small crustaceans, plankton, daphnia and fish.
Most jellyfish are carnivorous. Only a few species, such as the Cross jellyfish to feed mainly on plants. But by the carnivores goes for the people from any danger as a jellyfish-food.