Echinoderm

Author: Sarah Wirtz
__**EXAMPLES**__:



__**HABITAT**__: Echinoderms are primarily bottom dwelling marine animals that live in intertidal zones, deep sea trenches, coral reefs, and cold and tropical seas. They often serve as hosts to a large variety of symbiotic organisms inclu ding shrimps, crabs, worms, snails and even fishes.

__**TYPE OF COELOM:**__ Echinoderms have a well-developed, spacious coelom (an open, fluid-filled body cavity lined with tissue).

Echinoderms have an endoskeleton of spiny calcium-rich plates called ossicles. The spines protruding from their skin account for the phylum name Echinodermata.
 * __ENDOSKELETON or EXOSKELETON__:**

Echinoderms have eyespots which can detect light. However, their eyespots are not nearly as sharp as human eyes. They generally have a poorly developed nervous system. T he water-vascular system takes over some of the functions of this system as well as the circulatory system.
 * __TYPE OF NERVOUS SYSTEM__:**

__**FEEDER**__: Some echinoderms are carnivorous (starfish) others are detritus foragers (sea cucumbers) or planktonic feeders (basket stars). Many starfish have the peculiar ability to feed by turning the stomach inside out through the mouth; sea urchins scrape algae from rocks with five large teeth arranged in a structure known as "Aristotle's lantern."

__**SYMMETRY**__: Echinoderms are characterized by radial symmetry, several arms (5 or more, mostly grouped 2 left - 1 middle - 2 right) radiating from a central body). The body actually consists of five equal segments, each containing a duplicate set of various internal organs.

__**REPRODUCTION**__: Reproduction is carried out by the release of sperm and eggs into the water. Most species produce free floating larvae which feed on plankton. These larvae are bilaterally symmetrical, unlike their parents. When they settle to the bottom they change to the typical echinoderm features. Some brittle stars and sea stars can reproduce asexually by breaking a ray or arm or by deliberately splitting the body in half. Each half then becomes a whole new animal.

__**CIRCULATORY SYSTEM**__: Echinoderms have a very rudimentary circulatory systems but do have water pumped through their bodies as part of its very simple circulation system. While they do not have hearts, t he water-vascular system takes over some of the functions of this system as well as the nervous system.

__**ENDOTHERMIC or EXOTHERMIC**__. Echinoderms are exothermic. The temperature of the water determines their body temperature.

__**SEGMENTATION**__: Each segment contains a duplicate set of vital internal organs. For example, in sea stars (starfish), each segment is an individual arm.

__**WORKS CITED**__:


 * "Echinoderms." //Monroe County Women's Disability Network//. Web. 27 Mar. 2011. .
 * Mader, Sylvia S. "Enchinoderms." //Biology. Student Ed.// [S.l.]: Glencoe/McGraw Hill, 2007. 554-56. Print.
 * "Morphology of Echinodermata." UCMP - University of California Museum of Paleontology . Web. 24 Mar. 2010. http://www.ucmp.berkeley.edu/echinodermata/echinomm.html.
 * "Warm Sea Urchins on Acid." //Heating, Cooling and HVAC//. Web. 27 Mar. 2011. .
 * Zubi, Teresa. "Echinoderms (starfish, Brittle Star, Sea Urchin, Feather Star, Sea Cucumber)." //Starfish: Dive into the Coral Reef (underwater Photos, Information about Coral Reef Animals)- Tauche Zum Korallenriff (Unterwasser Fotos, Information über Rifftiere//. 13 Mar. 2010. Web. 27 Mar. 2011. .
 * Zubi, Teresa. "Sea Stars (Echinoderms) - Starfish Photos - Seesterne (Stachelhäuter)." //Starfish: Dive into the Coral Reef (underwater Photos, Information about Coral Reef Animals)- Tauche Zum Korallenriff (Unterwasser Fotos, Information über Rifftiere//. 21 Mar. 2011. Web. 27 Mar. 2011. .