Echinoderms

Echinoderms

 

 Echinoderms are characterized by several arms around a central mouth forming radial symmetry, spiny skin, a water vascular system, internal skeleton, and tube feet. A water vascular system is filled with fluid and carries out many essential body functions such as respiration, circulation, and movement. A tube foot is a suction cup like structure that operates from a muscle pulling the center of the center of the sucker upwards which creates suction so the foot can hold onto surfaces very strongly. 

Echinoderms sexually through external fertilization. In reproduction the sperm that is produced in the testes of a male and the eggs produced in the ovaries of a female are shed into the water where the fertilization then takes place. After the bilateral larvae swim around they settle to the bottom of the ocean where they develope into adults with radial symmetry.

Some examples of Echinoderms are

Sea Urchins

Sand Dollars

Brittle Stars

Sea Cucumbers

Sea Stars

 Cite:

Pictures:

http://www.biog1105-1106.org/labs/deuts/echinoderms.html

http://photos.igougo.com/pictures-photos-p308039-Bishop_Cap_Sea_urchin.html

http://www.scuba-equipment-usa.com/marine/NOV04/Black_Sea_Urchin%28Centrostephanus_rodgersii%29.html

http://www.wildabouttheworld.com/gallery/showphoto.php/photo/240

http://myfishtanks.info/fish-profile/saltwater-invertebrate-profiles/brittle-star-tiger-striped-serpent-seastar/

http://www.aquaticcommunity.com/news/lib/164

http://www.seascape-photos.co.uk/norway/norway02.html

Info:

http://www.starfish.ch/reef/echinoderms.html

Pretice Hall Biology book