Bacteria can grow rapidly, yet there are some that grow slowly under apparent optimal conditions. These organisms are usually present in environments with low levels of nutrients, and are not found in conditions of more plentiful nutrients. They are known as “oligotrophs”in contrast to “copiotrophs”, which are common in environments with greater nutritional opportunities. This essay asks why do the oligotrophs not occupy richer environments, and why are copiotrophs not more prevalent in chronic starvation environments? BioEssays 23:657–661, 2001. © 2001 John Wiley & Sons, Inc.