BIO 203 Lecture Notes - Lecture 10: Pisaster Ochraceus, Keystone Species, Pisaster
Document Summary
1a) in the food web of the rocky intertidal ecosystem, the pisaster orchraceus, or the purple sea star, is a dominant predator. They eat the predator below it, known as the thais. It also eats the species at the bottom of the food web, which are the gooseneck barnacles, chitons, limpets, and acorn barnacles (wagner 2010). Having the purple sea star in the food web is important. This is because it eats the other predator, also known as the mussels. If the purple sea star is removed, the mussels would have a great rise in numbers. As the number of mussels rises, the number of species on the bottom of the food chain decreases. This means that the pisaster orchraceus holds a vital role in keeping the number of mussels down to allow other species to live in that ecosystem (wagner 2010).
