Bacteria Click on image for full size (22K jpeg) Image courtesy of JPL/NASA

The bacteria are the most numerous of any of the living organisms. Bacteria have evolved an amazing diversity of means of acquiring the resources they need to live and reproduce. This remarkable diversity has enabled the bacteria to inhabit virtually every known environment on Earth, from the hot sulfur springs of Yellowstone to the glacial ice of the Arctic to the depths of the ocean floor.

The mere word "bacteria" typically conjures up images of germs and uncleanliness. The great deal of media attention paid to illnesses caused by bacteria such as E. coli and Salmonella, have helped earn the bacteria their notorious reputation as disease-causers. Though many diseases can be attributed to bacteria, other species are completely harmless and several perform beneficial functions, including converting milk into cheese and yogurt, and aiding in the production of pharmaceuticals to treat disease. Bacteria were among the first life forms on Earth.