Notes on Cnidaria Essay - 499 Words.
The circulation in cnidarians and ctenophores is aided by micropumps such as the cilia that line the pharynx in cnidarians, or by the ciliary action of comb plates in ctenophores (Martin and Johansen, 1965; Brusca and Brusca, 2003). In addition, some cnidarians display contractions of the circular and longitudinal layers of myoepithelial cells that line their gastrovascular cavities.
All species of coral are also Cnidarians. They provide an important habitat for a huge number of commercially fished species, including crustaceans and other invertebrates, fish, algae, seaweed and more. These coral reefs also have a huge economic impact due to tourism as well, as people flock to the reefs for snorkeling, diving and other activities. There is also a large worldwide trade in.
Introduction to Cnidaria Jellyfish, corals, and other stingers: Cnidarians are incredibly diverse in form, as evidenced by colonial siphonophores, massive medusae and corals, feathery hydroids, and box jellies with complex eyes. Yet, these diverse animals are all armed with stinging cells called nematocysts. Cnidarians are united based on the presumption that their nematocysts have been.
Marine Biology Chapter 7 - Cnidarians Essay. STUDY. Flashcards. Learn. Write. Spell. Test. PLAY. Match. Gravity. Created by. kfunchess. Thomas F. Greene's Second Edition Marine Science Textbook Marine Biology and Oceanography. Terms in this set (12) Explain how the jellyfish is adapted for floating. The shape and thinness of the membranes, and the low density of the layer of mesoglea between.
DK Science: Cnidarians. PHYLUM: CNIDARIA. Cnidarians are water animals that have a simple, usually symmetrical, body with a mouth opening. Stinging cells on tentacles around the mouth catch prey. Cnidarians are either bell-shaped and mobile, like the jellyfish, or tubes anchored to one spot, like coral and sea anemones. Jellyfish drift about in the ocean currents, trailing their tentacles.
Cnidaria is a phylum with about 11,000 species of animals. All of them are simple and aquatic, and most of them live in the sea.Some are colonial, composed of zooids which may be clones.Cnidarian zooids may take the form of polyps or medusae at different phases of their life. Cnidaria take their name from special cells which have organelles that sting: the nematocysts.
Cnidarians have four main groups. One of the main groups is the Anthozoa, it includes true corals, anemones, and sea pens. The Anthozoans are the most famous cnidarians. They have a long fossil record that extends back at least 550 million years. Polyp-like and sea pen-like fossils are most likely the oldest entozoan. In the Cambrian period the first mineralized coral-like organisms appeared.