The sand dollar, sea urchin, brittle star, sea star and sea cucumber are some examples of echinodermata. This family of marine animals lives on the sea floor and is distributed widely from intertidal areas to the darkest depths of the ocean.
There are around 7,000 species that fall under the classification of echinodermata, otherwise known as echinoderms. At least 800 of these can be found in the waters that make up the Great Barrier Reef. The name "echinodermata" comes from the Greek "echinoderma," meaning "spiny skin."
Echinoderms are easy to spot because of their radial symmetry, since all echinoderm species have five arms or multiples of five arms. They also have a calcium carbonate shell covered by skin. Echinoderms have fairly rudimentary respiratory systems that allow them to take oxygen in through tube feet and simple gills.