There are autotrophic and heterotrophic eubacteria. One type of the autotrophic eubacteria, called photosynthetic autotrophs, contain chlorophyll and undergo photosynthesis. An example of this is the genus Anabaena , a type of cyanobacteria. Cyanobacteria is a colony of individual unicellular organisms. Another type of autotrophic eubacteria are the chemosynthetic autotrophs.
Chemosynthetic autotrophs make their food by breaking down sulfur and nitrogen.
These type of eubacteria are of special importance, because they provide atmospheric nitrogen for other organisms. There are also two types of heterotrophs, parasites and saprophytes. The parasites get their food from other organisms, and saprophytes eat dead organisms. The saprophytes are also important, because they recycle the dead organism's energy. These bacteria live freely in the environment or have a symbiotic or parasitic relationship with other organisms.