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Published byLucinda Moody Modified over 8 years ago
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Echinoderms
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What are echinoderms? spiny skin internal skeleton water vascular system tube feet
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Form and Function Water Vascular system Filled with fluid respiration Circulation movement Madreporite ◦ sieve like structure ◦ opening to outside
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5 part radial symmetry bilaterally symmetrical deuterostomes ◦ blastopore develops into the anus
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Sea stars ◦ Tube Feet muscles pull up the center of the suction cup Tube feet allow them to walk and pull open prey.
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Sea Urchins use a 5 part jaw-like structure to scrape algae from rock
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Sea Lilies use tube feet to capture floating plankton
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Sea Cucumbers move like bulldozers taking in sand and detritus
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Sea Stars feed on mollusks ◦ Pry open shells ◦ Push stomach out of its mouth ◦ Secretes enzymes to digest mollusks in their own shells ◦ Pulls stomach and partially digested prey back in
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Respiration and Circulation surface respiration ◦ tube feet ◦ skin gills water vascular system ◦ carry oxygen, food and waste
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Excretion Digestive waste ◦ anus Nitrogen-containing cellular waste ◦ tube feet ◦ skin gills
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Nervous System not highly developed nerve rings Radial Scattered sensory cells ◦ detect light gravity chemicals released by potential prey
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Movement dependant on the type of endoskeleton Most use tube feet with other forms of locomotion
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Sand Dollars and Sea Urchins movable spines
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Sea Stars and Brittle Stars have flexible joints
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Sea Cucumbers plates over a soft muscular body wall
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Reproduction external fertilization are either male or female Sperm and eggs released into the water for fertilization Larva have bilateral symmetry develop radial symmetry
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Groups of Echinoderms
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Sea Urchins and Sand Dollars Large solid plates around internal organs Are detritivores ◦ eat algae Defense ◦ burrowing in the sand (sand dollar) ◦ wedging in rocks (sea urchins) ◦ using sharp spines
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Brittle Stars Common ◦ especially on coral reefs slender, flexible arms rapidly escape predators shed one or two arms ◦ keep moving when ◦ distract predators Are filter feeders ◦ detritivores Nocturnal
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Sea Cucumbers warty moving pickles Are detritus feeders, ◦ organic matter ◦ remains of plants ◦ remains of animals. Roam across deep sea floor herds of hundreds of thousands
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Sea Stars creep slowly along the sea floor carnivorous ◦ prey on bivalves pieces will grow into a new animal ◦ Must contain a portion of the central body
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Sea Lilies and Feather Stars oldest class of echinoderms filter feeders long feathery arms Common in tropical oceans
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Sea lilies live attached to the ocean bottom by long, stem-like stalks
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Feather stars live on coral reefs and use their tube feet to catch plankton
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Ecology of Echinoderms Sea urchins ◦ help control algae and other marine life Sea stars ◦ predators to control the population of other organisms
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Crown-of-Thorns sea stars threaten coral reefs Have poisonous spines Feeds almost exclusively on corals destroyed extensive areas of the Great Barrier Reef in Australia
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