Robert Paine conducted a study in which he removed sea stars, which prey mainly on mussels, from experimental plots in a rocky intertidal zone. With sea stars missing, mussels took over the plots, crowding out seven other species of invertebrates. In this community, sea stars function as ____.

A) endemic species
B) exotic species
C) pioneer species
D) keystone species
E) indicator species

Keystone Species

A species that has a disproportionately large effect on its ecosystem, influencing the types and numbers of other species in a community.

Sea Stars

Sea stars, also known as starfish, are marine invertebrates belonging to the class Asteroidea, known for their radial symmetry and a body plan consisting of a central disc from which arms (or rays) extend.

Intertidal Zone

The area of the shoreline that is exposed to the air at low tide and submerged under water at high tide, home to diverse organisms.