Chapter 3 : Discovering the Real Microbial World

Abstract:

Life is an interconnected web of organisms, and the main struts—the main fibers—in this web are evolutionary relationships. Today, microbiologists are developing a biologically meaningful understanding of microorganisms, so that we can realize how really important, and diverse the microbial world is. Many earlier molecular evolutionists knew that the technical power existed in molecular sequencing to determine distant phylogenetic relationships. Some understood that with the right molecules—for example, transfer RNAs—the full breadth of phylogeny could be spanned. Yet from their actions, it appeared that none of them appreciated the importance of determining a universal phylogenetic tree, what powerful evolutionary knowledge would emerge there from. The old prokaryote-eukaryote dichotomy was short on understanding and long on dividing biology into two camps, which more or less went their separate ways. The emphasis was on the ways in which prokaryotes and eukaryotes differ, not on why they differ and what sort of common ancestor they share. The archaea are central to a real revolution that is still occurring in microbiology. They epitomize the importance of phylogeny and the power of molecular biology to reveal evolutionary history.