Spiny skinned animals with radial symmetrical body plan. Rays emanating from a common center. Internal skeleton of hardened plates of calcium

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Phebe Jordan
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1 Echinodermata

2 Spiny skinned animals with radial symmetrical body plan. Rays emanating from a common center. Internal skeleton of hardened plates of calcium carbonate. Water vascular system and tube feet locomotion, feeding, respiration, internal transport, and waste removal Close to chordates because of the development of a bilateral larval stage that is similar to that in chordates and the presence of an internal skeleton.

3 Vascular System: Madreporite Calcareous sieve like opening to the outside that is used to filter into the water vascular system. Ring canal at the center of the seastar from which the filtered water from the madreportie is distributed to the radial canal Radial canal carry water to the ampulla (reservoir portion) of the tube feet. Tube feet off radial canal

4 Feeding: Carnivorous Sea stars pry open clam shells with tube feet and extend their stomachs and digestive juice right onto shell. Herbivors Sea urchins scrape off algae, some sea stars. Filter feeders sea lilies, feather stars. Detritus feeders sea cucumbers, some sea stars.

5 Respiration: Some have skin gills Thin walled tube feet

6 Internal Transport: Nutrients move in fluid within body cavity and digestive glands

7 Excretion: Solid anus except in brittle stars Nitrogenous waste gills and tube feet

8 Response: Primitive nervous system. Nerve ring and radial nerve. Some have statocysts (A small organ of balance in many invertebrates, consisting of a fluid-filled sac containing statoliths that stimulate sensory cell).

9 Response Con t Chemoreceptors for finding food. Sea stars have photoreceptors (light/dark). Few protective responses hide under rocks

10 Movement: Tube feet sea stars and sea cucumbers Movable spines urchins and sand dollars Swim feather stars Flexible arms brittle stars

11 Reproduction: Separate sexes diecious External fertilization up to 2,500,000 eggs per season. Free swimming larva in plankton bilateral symmetry. Attaches by a stalk that degenerates when adult forms. (except in crinoids).

12 Regeneration: Clam fisherman fishermen in the past tried to kill sea stars by chopping them into pieces but the more they cut the more sea stars formed as they are able to reproduce through fragmentation as long as part of the ring canal was present.

13 Classes: Asteroidea sea stars intertidal zone About 1,800 species Often brightly coloured Most are carnivorous, preying on bivalves and other mollusks Arms are short and thick with spacious coelomic cavities containing gonads and branches of saclike digest system

15 Ophiurodea brittle star and basket star Most abundant group with over 2,000 species. Inhabit ocean floors worldwide, sometime in the millions. Arms are long and slender Coelomic cavity, gonads, and digestive system mostly confined to central disk Mostly suspension or detritus feeders some carnivorous.

17 Echinoidea sea urchins, sand dollars Spacious coelom containing 2 5 gonads and a coiled digestive tract. Mostly mobile grazers feeding on algae (sea urchins) or burrowing detritus feeders (sand dollars) All the plates of bear calcareous spines mounted on a ball-and-socket joint that s provided with muscles.

19 Echinoidea con t Pedicellarias (A defensive organ like a minute pincer present in large numbers on an echinoderm) of sea urchins are more complex than those of the sea stars. They are on tall moveable stalks and most have three jaws. They are specialized for different functions defence, cleaning, and even feeding

20 Holothuroidea sea cucumbers Soft to leathery, elongated bodies with microscopic or larger scale like ossicles (A small piece of calcified material forming part of the skeleton) in body wall Spacious coelom containing a single gonad and coiled digestive tract. Buccal tube feet greatly enlarged as feeding tentacles. Sedentary suspension feeders or creeping or burrowing detritus feeders.

21 Crinoidea sea lilies and feather stars Like an upside down sea star with the mouth pointing up. Branching arms with side branches (pinnules) containing gonads and bearing tube feet. Feed on tiny organisms and fine particles in the water, and the outspread arms and pinnules form an elegant food collecting device. Some feather stars move about constantly; others remain in the same spot for months at a time. Sea lilies are sessile.

23 Sea daisies The most recently discovered class of animals discovered in Live on sunken wood deep in the sea. Small animals, less than 1cm in diameter. No internal digestive system.

25 Echinoderms in the World Population explosions - crown of thorns are destroying coral reefs. Food Urchin eggs Anticancer and viral drugs

ADVANCED INVERTEBRATES HAVE COMPLEX BODIES AND INTERNAL SYSTEMS

ADVANCED INVERTEBRATES HAVE COMPLEX BODIES AND INTERNAL SYSTEMS Arthropoda Most successful phylum on Earth Exoskeleton chitin Striated muscle Articulation Crayfish, lobsters, shrimp, crabs Echinodermata