What universal themes or concepts seem to underlie and govern the behavior of microorganisms, particularly the bacteria? (By "behavior" we mean things like the microorganism's modes of growth, survival, nutrition, interaction, communication, and reproduction.) Think in terms of broad concepts that apply across many different ecosystems (soil and water, plants and animals, clinical and industrial). Address two such broad concepts that apply to nearly all microbes, tell why these concepts are so important to understanding microorganisms and how they interact with us and the environment. Illustrate your answer with specific examples whenever possible.