Jenis Crinoid Feather Stars

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o So each arm is a series of ossicles extending outward from the body. • The arms contain extensions of coelomic (body cavity), nervous, water vascular, and reproductive systems • They also have an ambulacra (radial area) groove bordered by fingerlike tube feet, or podia, which are extensions of the water vascular system as well. They are also used in suspension feeding and respiration • All living crinoids are pinnulate, bearing a small side branch, pinnule, on alternating sides of successive ossicles along the arm. These pinnules bear the food-gathering tube feet. o Pinnules arose in several lineages during the Paleozoic and are characteristic of all post-Palaeozoic crinoids. • <strong>Crinoid</strong>s have muscles, nerves, a gut, a reproductive system and other features Feeding of advanced animals. • They are all passive suspension and filter feeders and because they produce no feeding or respiratory current, they rely more on the water movement around them, feeding by filtering small particles of food from those seawater currents. • Their diet consists of a variety of protists (i.e. diatoms and other unicellular algae, foraminiferans, actinopods), invertebrate larvae, small crustaceans, and detrital particles. • To feed they use their featherlike arms that radiates from the central body which each bears an open ambulacra groove bordered by triads od fingerlike podia
(tube feet) which as mentioned before, are terminal extensions of the water vascular system. • This is a complex system of muscles, canals, pouches, bladders, tubes, and suckers connecting to numerous tube feet that allow Echinoderms to use this hydraulic system for locomotion, food, waste transportation, and respiration. • They are also typically nocturnal and will come out after dark to perch upon a coral or other structure. • Then they spread out their arms perpendicular to the current to feed, turning their “plumage” into the current to feed while being restricted to one spot. • They then their arms and feet to trap their food and flicking/filtering it into their mouths. • After a food particle is captured, the shortest tube foot wraps it in mucous secretions where ciliary tracts on the groove floor then transport it toward the mouth and ingested. o The mouth descends into a short esophagus and because there is no true stomach, it connects directly to the intestine, which runs in a single loop right around the inside of the calyx. o The intestine often includes numerous diverticulae (outpouching of a hollow or a fluid-filled structure in the body), some of which may be long or branched. o The end of the intestine opens into a short muscular rectum, which ascends towards the anus. Waste is collected by phagocytic (white cell) coelomocytes (immune cells of lower coelomate animals). • Oxygen is absorbed primarily through the tube feet, which are the most thin- walled parts of the body, using the water vascular system. http://www.youtube.com/watch?v=8uZJVSFwixY
Page 1 and 2: Crinoid Feather Stars Scientific (G
Page 3 and 4: Evolutionary Relationships Fossil C
Page 5: o Their Pinnules arose in several l
Page 10 and 11: Locomotion • Most crinoids are fr
Page 12 and 13: Reproduction and life cycle • The
Page 14: • Thy approximate 80 surviving sp

Jenis Crinoid Feather Stars

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