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Phylum Echinodermata

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Presentation on theme: "Phylum Echinodermata"— Presentation transcript:

1 Phylum Echinodermata

2 Phylum Characteristics: Name: (Greek) echinos = spiny; derma =skin Calcareous endoskeleton in the form of ossicles Most adults with pentaradial symmetry Larva with bilateral symmetry Water-vascular system (including tube feet) for locomotion, attachment, and/or feeding Digestive tract Hemal system (to circulate fluids and possibly distribute nutrients) Nervous system (= nerve net, nerve ring, and radial nerves)

3 Class Crinoidea Sea Lilies and feather stars Most primitive of all living echinoderms Sea Lilies attach to substrate by a stalk – Unattached end = crown (of 5 branched arms) – Double row of tube feet along each arm – Crown attached to stalk at calyx – Stalk may have cirri (projections) *feather stars lack a stalk and are swim/crawl using their arms

4 messing/crinoids/8%20Feedin g%20mechanism_files/image 004.jpg 051026/a919_1857.jpg Sea Lilies

5 /080425cyrd1818m3.jpg&imgrefurl= &usg=__paR9PIvtJNr8UapDk- H_SyS1u0M=&h=216&w=216&sz=59&hl=en&start=33&itbs=1&tbnid=TcZY59QLNb31lM:&tbnh=107&tbnw=107&p rev=/images%3Fq%3Dfeather%2Bstars%26gbv%3D2%26ndsp%3D18%26hl%3Den%26sa%3DN%26start%3D18 Fossilgroups/Ophiuroidea/Feather_Star _large.jpg Feather Stars

6 Suspension/Filter feeding: Tube feet catch prey and cilia in ambulacral groove carry it to mouth Lack nerve ring Can be dioecious or monoecious (male gametes develop before female gametes) Fertilization may be external or embryos may be brooded on arms of adult Capable of regeneration

7 Class Asteroidea Sea Stars (and Sea Daises?) 5 arms around a central disk, each with an ambulacral groove and tube feet Some arms may have photoreceptors/ocelli on tube feet at tips Dermal Branchiae (thin folds of body) function in gas exchange Some have pedicellariae (pincherlike structures) which may help clean & protect

8 2 sides: oral/aboral – Aboral side contains anus and madreporite (connects ring canal to outside -helps to replace water into water-vascular system) – Oral side has mouth connected to esophagus, stomach (with 2 regions), and short intestine Feed on snails, bivalves, crustaceans, polychaetes, corals, detritus, etc.


10 science/Zoology/Aboral_surface_of_star_ fish.gif

11 Known for regeneration (asexual reproduction) Most Dioecious (internal difference) – 2 gonads in each arm External fertilization le/view/starfish_larva.jpg/31302621 /starfish_larva.jpg


13 es/NGS/Shared/StaticFiles/Photography/Images/Con tent/necklace-sea-star-696678-sw.jpg Th2WI/AAAAAAAAFxM/QaFw- 1gwPLo/s400/changi310808p01.JPG 12pam03/ thorns-sea-star-coral-killerxx.jpg

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