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Download Echinodermata - Effingham County Schools
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Phylum Echinodermata (Means spiny skin) https://vimeo.com/37295088 Echinodermata Classes Asteriodea(Stelleroids) Sea stars Aka starfish Echinodermata Classes Crinoidea/Crinoids Feather stars Sea lilies Echinodermata Classes Echinoidea/Echinoids Sea urchins, sand dollars Compact body within a shell No arms, often spiny Echinodermata Classes Holothuroidea (Holothuriods) Sea cucumbers Elongated body Leathery body wall with embedded ossicles (bony plates) Ophiunoidea Brittle stars, Basket stars Echinodermata Common Characteristics Radial Symmetry as opposed to bilateral Like spokes on a wheel Echinodermata Common Characteristics Body may be round Or Cylindrical Or star shaped With 5 or more ambulacra (radiating ‘arms’) Echinodermata Common Characteristics Endoskeleton with spines or spicules ( made of calcium carbonate plates called ossicles) Can regenerate lost parts Echinodermata Common Characteristics No head or brain Few specialized sensory organs Simple Nervous system Nerve ring / radial nerves No excretory organs Echinodermata Common Characteristics Water Vascular System Water is taken in at the madreporite Helps with respiration, Circulation and movement Specialized structures… •Mouth and anus – ingestion and excretion of digestive wastes •Madreporite – sieve like structure through which water is taken in. • Some species - gills Sea urchins have pedicellarines in their spines. •Used for protection and feeding. • Tube feet for movement •Gonads - make gametes (sperm and eggs) Echinodermata Anatomy Mouth Underside = Oral side Anus Top side = Aboral side Echinodermata Nutrition Most sea urchins scrape algae off surfaces They have specialized mouthparts for this Called Aristotle’s lantern A few are scavengers or predators Echinodermata Nutrition Brittle stars are mostly scavengers They crawl about on the bottom looking for dead stuff Some are active filter feeders Or just lay about waiting for food to float by and stick to them Echinodermata Nutrition Sea stars are carnivores They tear open mollusks with their arms Then extrude their own stomach out of their mouths to release digestive juices into the clam’s body. http://www.bbc.co.uk/nature/life/Sunflower_starfish#p005bpt2 Answer to #6 on the hand out They eat mollusks like clams and mussels, some eat coral (‘Crown of thorns’) http://www.arkive.org/crown-of-thorns-starfish/acanthaster-planci/video-00.html https://www.youtube.com/watch?v=-ardrFZuFkU Echinodermata Reproduction May be hermaphrodites Or separate male and female organisms Usually release sperm / egg into the water column External fertilization Many species synchronize this, along the lunar cycle
