Bacteria
Bacteria is a generic term for any single-celled, microscopic (usually 0.5 to 5 microns, although can be smaller or larger) prokaryote carbon-based biological organisms.
May be spherical, rod shaped, spiral, even (on some worlds) amoeboid. Naturally occurring bacterial lifeforms have been found in most life-bearing ecosystems; indeed, they are one of the most basic forms of life in the Galaxy. Although bacteria differ greatly in metabolism and chemistry, they share the basic functions of decmoposers, autotrophs, and symbionts. Because of their simplicity, rapid reproduction rate, and the ease with which their genetic material can be modified, many kingdoms of bacteria are frequently used for biotechnological purposes and modifications.
Importance as symbionts
Most, if not all, known sentient species rely on a symbiotic relationship with a wide assortment of bacterial species for a myriad of purposes, including digestion of food. In one well known occasion however, that of the superbacterium, the bacteria has further evolved into a kind of a "auxiliary reproductive system" for the host species, taking over many macrobody functions. This peculiar form of interaction of the micro- with the macroscopic has been recorded in the Bacterians, which is where they got the name.
