Jellyfish are animals of the phylum Cnidaria, class Scyphozoa, order Semaeostomeae and family Cyaneidae. The phylum Cnidaria is an incredibly ancient group of invertebrate animals, stretching back hundreds of millions of years. Jellyfish are among the oldest types of multicellular animals. True jellyfish have a number of distinguishing characteristics by which they are classified.Continue Reading
Jellyfish are universally planktonic in their adult stage, meaning that they have only minimal ability to propel themselves through water, and are carried along freely by ocean currents. Jellyfish have minimal sensory capabilities and no nervous systems, with each part responding only to its immediate environment without any coordination with the rest of the organism. The body of a jellyfish is composed of a gel-like substance known as mesoglia, which is about 90 percent water, surrounded by a skin only a single cell in thickness.
Jellyfish have distinctive weapons, known as nematocysts, for hunting prey. These are venom-bearing barbs found in great numbers in their tentacles. These weapons are shared only by jellyfish and related groups, such as sea anemones. Jellyfish use one of the major cnidarian body plans, a free-floating bell with trailing tentacles, known as a medusa, while anemones use the other body plan, a sessile stalk with upward-pointed tentacles, known as a polyp.Learn more about Jellyfish
Jellyfish are invertebrates composed of gelatinous substances and water. The creatures are similar to sea anemones and coral, which all belong to the phylum Cnidaria, as stated by the National Oceanic and Atmospheric Association.Full Answer >
Jellyfish season occurs during the summer months when the nettle, moon and Australian jellyfish invade thousands of square miles of the Gulf of Mexico. The jellyfish are proliferate in an area called the Dead Zone, where polluted water from the Mississippi River pours into the Gulf of Mexico and allows for few things to survive other than jellyfish.Full Answer >
Jellyfish are opportunistic carnivores that will eat almost anything they come across. Smaller jellyfish consume plankton, larger ones eat fish eggs, crustaceans and snails, and the very largest jellyfish can catch and eat whole fish. Jellyfish can also be cannibalistic.Full Answer >
Jellyfish release thousands of larvae that settle on the ocean floor and turn into polyps that become baby jellyfish. Male jellyfish release sperm into the water and the sperm either fertilizes eggs that the female releases into the water or enter through the female's mouth and fertilize her eggs.Full Answer >