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Phylum Echinodermata MARINE INVERTEBRATES. Characteristics  All marine  Known as spiny-skinned animals  Endoskeleton known as the test is made of calcium.

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Presentation on theme: "Phylum Echinodermata MARINE INVERTEBRATES. Characteristics  All marine  Known as spiny-skinned animals  Endoskeleton known as the test is made of calcium."— Presentation transcript:

1 Phylum Echinodermata MARINE INVERTEBRATES

2 Characteristics  All marine  Known as spiny-skinned animals  Endoskeleton known as the test is made of calcium plates or ossicles with protruding spines  Includes sea stars, brittle stars, sand dollars, sea urchins, & sea cucumbers

3 Characteristics  Undergo metamorphosis from bilateral, free-swimming larva to sessile or sedentary adult  Larval stage known as dipleurula or bipinnaria  Adults have pentaradial (5 part) symmetry  Lack segmentation or metamerism Bipinnaria Larva


5 Characteristics  Coelomate  Breathe through skin gills as adults  Capable of extensive regeneration

6 Characteristics  Ventral (lower) surface called the oral surface & where mouth is located  Dorsal (upper) surface known as aboral surface & where anus is located  Have a nervous system but no head or brain in adults  No circulatory, respiratory, or excretory systems

7 Characteristics  Have a network of water-filled canals called the water vascular system to help move & feedwater vascular system  Tube feet on the underside of arms help in moving & feeding  One-way digestive system consists of mouth with oral spines, gut, & anus  Deuterostomes (blastopore becomes the anus)


9 Characteristics  Separate sexes  Reproduce sexually & asexually

10 Includes 5 classes:  Crinoidea - sea lilies & feather stars  Asteriodea - starfish  Ophiuroidea - basket stars & brittle stars  Echinoidea - sea urchins & sand dollars  Holothuroidea - sea cucumbers

11 1) Crinoidea Characteristics  Sea lilies & feather stars Sea lilies & feather stars  Sea lilies have a long stalk with branching arms that attach them to rocks & the ocean bottom  Feather stars can detach & move around  Mouth & anus on upper surface

12 1) Crinoidea Characteristics  May have 5 to 200 arms with sticky tube feet to help capture food (filter feeders) & take in oxygen  Common in areas with strong currents & usually nocturnal feeders

13 2) Asteroidea CharacteristicsAsteroidea  Usually sedentary along shorelines  Starfish or sea stars Starfish or sea stars  Come in a variety of colors  Prey on bivalve mollusks such as clams & oysters

14 2) Asteroidea Characteristics  Have 5 arms that can be regenerated  Arms project from the central disk  Mouth on oral surface (underside) Mouth  Range in size from 1 cm to 1 m

15 Body Plan of Sea Star  Have an endoskeleton made of calcium plates  Sharp, protective spines made of calcium plates called ossicles found under the skin on the aboral (top) surface  Have pedicellariae or tiny, forcep-like structures surrounding their spines to help clean the body surface Aboral Surface

16 Water Vascular System  Network of canals creating hydrostatic pressure to help the starfish move  Water enters through sieve plate or madreporite on aboral surface into a short, straight stone canal  Stone canal connects to a circular canal around the mouth called the ring canal

17 Water Vascular System  Five radial canals extend down each arm & are connected to the ring canal  Radial canals carry water to hundreds of paired tube feet

18 Water Vascular System

19 3) Class Ophiuroidea  Largest class of echinoderms  Includes basket stars & brittle stars  Live on the ocean bottom beneath stones, in crevices, or in holes

20 3) Class Ophiuroidea  Have long, narrow arms resembling a tangle of snakes  Arms readily break off & regenerate  Move quicker than starfish  Feed by raking in food with arms or trapping it with its tube feet

21 4) Class Echinoidea  Includes sea urchins & sand dollarssea urchins sand dollars  Internal organs enclosed by endoskeleton or test made of fused skeletal plates  Body shaped like a sphere (sea urchin) or a flattened disk (sand dollar)  Lack arms


23 4) Class Echinoidea  Bodies covered with movable spines  Have a jawlike, crushing structure called Aristotle's lantern to grind food  Use tube feet to move

24 4) Class Echinoidea  Spherical shape  Live on ocean bottom  Scrape algae to feed  Long, barbed spines make venom for protection

25 4) Class Echinoidea  Flattened body  Live in sand along coastlines  Shallow burrowers  Have short spines

26 5) Class Holothuroidea  Includes sea cucumber  Lack arms  Shaped like a pickle or cucumber  Live on ocean bottoms hiding in caves during the day  Have a soft body with a tough, leathery outer skin


28 5) Class HolothuroideaHolothuroidea  Five rows of tube feet run lengthwise on the aboral (top) surface of the body  Have a fringe of tentacles (modified tube feet) surrounding the mouth to sweep in food & water  Tentacles have sticky ends to collect plankton  Show bilateral symmetry  Can eject parts of their internal organs (evisceration) to scare predators; regenerate these structures in daysevisceration

29 5) Holothuroidea  Bulb-like sacs or ampulla on the upper end of each tube foot contract & create suction to help move, attach, or open bivalves  Rows of tube feet on oral surface (underside) are found in ambulacral grooves under each arm

30 Feeding & Digestion  Tube feet attach to bivalve mollusk shells & create suction to pull valves apart slightly  Starfish everts (turns inside out) its stomach through its mouth & inserts it into prey  Stomach secretes enzymes to partially digest bivalve then stomach withdrawn & digestion completed inside starfish

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