Bacterial Complexity: More Is Different on All Levels

This chapter presents new clues, drawn from the morphogenesis of bacterial colonies, for the challenges of complexity posed in the integrative study of biological systems (systemic or systems biology). Some exciting observations of complex cooperative behavior of bacteria in colonies are presented, guided by the assumption that they might shed new light on the foundations and evolution of biocomplexity in general. The chapter is aimed at researchers of different disciplines—microbiology, biology, chemistry, physics, mathematics, and computer science—so, to make it comprehensible to all, I have avoided the use of specialized terminology and limited the presented details.

Bacteria are not the simple, solitary creatures of limited capabilities they were long believed to be. The impression that bacteria act as unsophisticated, solitary creatures stems from years of laboratory experiments in which they were grown under artificial conditions. However, under the harsh conditions in the wild, or in the laboratory under growth conditions that mimic natural environments, these versatile organisms work as a team and employ chemical communication to form highly complex colonies of 10⁹–10¹² bacteria each [1–11]. Such colonies behave much like a multicellular organism with cell differentiation, distribution of tasks, and, in some cases, even modules that act like reproductive organs.