Echinoderms

= = = ﻿What are Echinoderms ? ﻿Echinoderms are characterized by spiny skin, internal skeleton, a water vascular system, and suction cuplike structures called tube feet. Most also have a five-part radial symmetry. They are also deuterostomes which is when the blastospore develops into an anus. Echinoderms include Sea urchins, sand dollars, brittle stars, sea cucumbers, sea stars, sea lilies and feather stars. =



= Form & Function = =They have a water vascular which is filled with fluid and carries out essential body functions including respiration, circulation and movement. A madreporite, a sieve like structure, connects to a ring canal and from there five radial canals extend along the body segments. They have hundreds of tube feet which are structures that are similar to suction cups. Each tube foot has a sucker at the end and muscles pull the center upwards forming a cup shape which makes the foot pull on the surface. This is what gives them the ability to get pray and move around. =

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= Feeding =

Sea Urchins use a five part jaw like structure. Sea Lilies use their tube feet. Sea Cucumbers move like bulldozers. Sea Stars pushes its stomach out through its mouth, pours enzymes, and digests the food in its own shell (if eating mollusks).

= ﻿ = = <span style="color: #ff005e; font-family: 'Comic Sans MS',cursive; font-size: 250%;">Respiration and Circulation = =<span style="color: #ff5050; font-family: Arial,sans-serif; font-size: 27px; font-weight: normal; line-height: 32px;">In some species, the thin-walled tissue of the tube feet provides the main surface for respiration. In other species, small outgrowths called skin gills also function in gas exchange. The circulation of essential materials and wastes take place in the water vascular system. =

= <span style="color: #ff005e; font-family: 'Comic Sans MS',cursive; font-size: 250%; font-weight: normal; line-height: 45px;">Excretion and Response = = <span style="color: #ff5050; font-family: Arial,sans-serif; font-size: 28px; font-weight: normal; line-height: 33px;"> Digestive wastes are released through the anus. Nitrogen- cont aining cellular wastes are excreted in form of ammonia. They don’t have a highly developed nervous system; Most have a nerve ring around the mouth; also radial nerves.Some have sensory cells that detect light, gravity and chemicals =

= <span style="color: #ff005e; font-family: 'Comic Sans MS',cursive; font-size: 250%;">Movement = <span style="color: #ff5050; font-family: Arial,sans-serif; font-size: 30px; line-height: 36px;">Most move by using tube feet, however some use other methods. Sand Dollars and Sea Urchins have movable spines attached to its endoskeleton. Sea Stars and Brittle Stars have flexible joints. Plates in Sea Cucumbers are reduced and contained in a soft, muscular body wall.

= <span style="color: #ff005e; font-family: 'Comic Sans MS',cursive; font-size: 250%; line-height: 49px;">Sea Urchins and Sand Dollars =

<span style="color: #ff5050; font-family: Arial,sans-serif; font-size: 26px; line-height: 28px;">They have large, solid plates that form a box around their internal organs. Many are detritivores which means they eat a lot of algae. Sand Dollars burrow under layers of sand <span style="color: #ff5050; font-family: Arial,sans-serif; font-size: 26px; line-height: 28px;">and mud while Sea Urchins wedge themselves in rocks <span style="color: #ff5050; font-family: Arial,sans-serif; font-size: 26px; line-height: 28px;">. <span style="color: #ff5050; font-family: Arial,sans-serif; font-size: 26px; line-height: 28px;">

= <span style="color: #ff005e; font-family: 'Comic Sans MS',cursive; font-size: 250%; line-height: 45px;">Brittle Stars = <span style="color: #ff5050; font-family: 'Comic Sans MS',cursive; font-size: 150%; line-height: 26px;">They have slender, flexible arms and can rapidly escape their predators. They detach one of their arms, which keeps moving to distract their predators while they escape. They hide by day and wander around at night.



= <span style="color: #ff005e; font-family: 'Comic Sans MS',cursive; font-size: 250%; line-height: 45px;">Sea Cucumbers = <span style="color: #ff5050; font-family: 'Comic Sans MS',cursive; font-size: 150%;">They look like warty pickles. Most are detritus feeders that move along the sea floor while sucking up organic matter and remains of other animals. They travel in herds, or large groups. = = <span style="color: #ff005e; font-family: 'Comic Sans MS',cursive; font-size: 46px; line-height: 68px;">**Sea Star**  <span style="color: #ff5050; font-family: 'Comic Sans MS',cursive; font-size: 150%; line-height: 26px;"> <span style="font-family: Arial,sans-serif;">They creep slowly along the ocean floor. Most are carnivorous that prey on bivalves. Most have the ability to repair themselves once they have been detached as long as they have a portion of the central part of the body. <span style="color: #ff5050; font-family: Arial,sans-serif; font-size: 24px; line-height: 0px; overflow-x: hidden; overflow-y: hidden;"> = <span style="color: #ff005e; font-family: 'Comic Sans MS',cursive; font-size: 250%; line-height: 45px;">Sea Lilies and Feather Stars   = <span style="color: #ff5050; font-family: 'Comic Sans MS',cursive; font-size: 150%; line-height: 23px;">Have long, feathery arms. Common in tropical oceans of today. They live attached to the ocean bottom by a long, stem like stalk. Most live in coral reefs and rely on tube feet to catch prey.