The Evolution of microbial life: paradigm changes in microbiology

Abstract

Bacteria are not as structurally or functionally simple as we believed. Bacteria live and die in complex communities that in many ways resemble multicellular organisms. The release of pheromones induces bacteria in a population to respond in concert by changing patterns of gene expression, a phenomenon called quorum sensing. Bacteria want what all other organisms want: to grow, to eat, to reproduce themselves; if their surrounding conditions are good, they will stay; if things are better somewhere else, they will move; if threatened, they will escape; and if the world around them changes, they must change. These are the basics of life: access to nutrients, consumption of nutrients for reproduction, dispersion, escape from predators, and differentiation. Today, it is common knowledge that the majority of microorganisms play essential roles in maintaining life on Earth. We, and our fellow macrobes, are ultimately reliant on the manifold activities of the invisible microbial world. The miniscule size of its members belies their tremendous importance.