The first issue to get settled is that the shape of a
bacterium has biological relevance. One argument favoring
this assertion is that even though bacteria have a wide
variety of shapes, any one genus typically exhibits a
limited subset of morphologies, hinting that, with a universe
of shapes to choose from, individual bacteria adopt
only those that are adaptive. Another clue is that some
bacteria can modify their morphology in response to
environmental cues or during the course of pathogenesis
(e.g. reference [6
]), suggesting that shape is important
enough to merit regulation.