Motility, mixing, and multicellularity

Abstract. A fundamental issue in evolutionary biology is the transition from unicellular to multicellular organisms, and the cellular differentiation that accompanies the increase in group size. Here we consider recent results on two types of “multicellular” systems, one produced by many unicellular organisms acting collectively, and another that is permanently multicellular. The former system is represented by groups of the bacterium Bacillus subtilis and the latter is represented by members of the colonial volvocalean green algae. In these flagellated organisms, the biology of chemotaxis, metabolism and cell-cell signaling is intimately connected to the physics of buoyancy, motility, diffusion, and mixing. Our results include the discovery in bacterial suspensions of intermittent episodes of disorder and collective coherence characterized by transient, recurring vortex streets and high-speed jets of cooperative swimming. These flow structures markedly enhance transport of pas...

• Type: Journal
• Year: 2007
• Where: GPEM
• Authors: Cristian A. Solari, John O. Kessler, Raymond E. Goldstein
• Keywords: Bacterium Bacillus Subtilis, GPEM 2007, Multicellular, Multicellular Organisms