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What are the main features of Coelenterata?
Characteristics. All coelenterates are aquatic, mostly marine. The bodyform is radially symmetrical, diploblastic and does not have a coelom. The body has a single opening, the hypostome, surrounded by sensory tentacles equipped with either nematocysts or colloblasts to capture mostly planktonic prey.
What are the economic importance of cnidarians?
Sea anemones are eaten in some areas of Asia and North America. Throughout the tropics where reefs are accessible, coral skeletons are used as building material, either in blocks or slaked to create cement. Another use for cnidarian skeletons is in jewelry.
How are coelenterates different from other invertebrates?
an aquatic invertebrate animal of the phylum Cnidaria (formerly Coelenterata), which includes jellyfishes, corals, and sea anemones. They are distinguished by having a tube- or cup-shaped body.
What do you mean by Coelenterata?
coelenterate. / (sɪˈlɛntəˌreɪt, -rɪt) / noun. any invertebrate of the phylum Cnidaria (formerly Coelenterata), having a saclike body with a single opening (mouth), which occurs in polyp and medusa forms. Coelenterates include the hydra, jellyfishes, sea anemones, and corals.
What are economic importance of Coelenterates?
Coelenterates as a whole are of little economic importance. Seldom used as food by man, they are eagerly devoured by certain fishes and by invertebrates such as the crownof thorns starfish. Certain corals used as ornaments and for the manufacture of jewelry have become rare because of exploitation.
What is the purpose of cnidarians?
Cnidarians are carnivorous animals. They use cnidocytes on the surface of their tentacles to release nematocysts for attacking and capturing prey. The immobilized prey can then be brought into the coelenteron through the mouth. Medusae also have oral “arms” that assist in capturing and ingesting prey.
Why are Coelenterata called cnidarians?
Coelenterates are called Cnidarians because they contain specialized cells called cnidoblasts. They possess stinging structures called nematocysts.
What is the function of Medusa in Coelenterata?
The medusa is a free-swimming form; it moves by rhythmic muscular contractions of the bell, providing a slow propulsive action against the water. The other principal body type of the adult cnidarian is the polyp, a stalked, sessile (attached) form. Compare polyp.
What are the function of tentacles?
Tentacles are slender, flexible organs on the head. They may function in sensory perception and in actually securing food.
What is the use of tentacles in phylum Coelenterata?
Tentacles have special structures known as the nematocysts which help in capturing and paralyzing prey. Coelenterates simply wave their tentacles and when a prey comes in contact, the nematocysts inject the toxin that paralyses or kills the prey. Nematocysts are the most distinguishing feature of this phylum.
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