Microbes first appeared on earth about 3.8 billion years ago. They are critically important in sustaining life on our planet. Microbes drive the chemistry of life and affect the global climate. Microbial cycling of such critical chemical elements as carbon and nitrogen helps keep the world inhabitable for all life forms. Microbes generate at least half the oxygen we breathe.
Microbes offer unusual capabilities reflecting the diversity of their environmental niches.
These may prove to be useful as a source of new genes and organisms of value in addressing bioremediation, global change, biotechnology, and energy production. Microbial studies will help us define the entire repertoire of organisms in specialized niches and, ultimately, the mechanisms by which they interact in the biosphere. Diversity patterns of microorganisms can be used for monitoring and predicting environmental change. Microbes are roots of life's family tree. An understanding of their genomes will help us understand how more complex genomes developed.