(Djupfest - Sør-Trøndelag / 6 meters / 9.25.2005)

Phylum: Echinodermata

 

Norwegian: pigghuder

Echinodermata includes exclusively marine species. No echinoderms exist on land or in fresh water. The name originates from Greek and means spiny skin. Not all have spines in their skin, although it is quite common. An outer layer of calcareous material is typical. It may form a shell as in the sea urchins, or plates connected by a flexible material, as in the sea stars. Most echinoderms live their adult lives on the bottom, clinging to the ground with hydraulic suckers. Hydraulics (sea water) is used to nutrition transport nutrition around the body, as well. Sperm and eggs are released in the water. The larvae live their first phase in the water before they attach themselves to the seabed.