Sunday, February 21, 2016

Sea Stars

Starfish are marine invertebrates. There are about 2,000 species of starfish calling the world's oceans home, from the tropics to frigid polar waters. They are found from the intertidal zone down to abyssal depths, 6,000. The fossil record for starfish is ancient, dating back to the Ordovician around 450 million years ago.Starfish and other echinoderms are sensitive to marine pollution. The common starfish is considered to be a bioindicator for marine ecosystems