This division is composed of marine organisms known as "fire" algae, so named because most of them are red in color. Fire algae are an important component of ocean plankton. The major class within this division is Class Dinophyceae, the dinoflagellates. There are over 1100 species in this division. Members of Pyrrophyta are single-celled, photosynthetic organisms that move via two flagella. They store their food as starch, and their cell walls are made of cellulose. They usually reproduce asexually.