(August 2003) Microbes are everywhere. They populate the air, the water, the soil, and have even evolved intimate relationships with plants and animals. Without microbes, life on earth would cease. This is due mainly to the essential roles microbes play in the systems that support life on earth, such as nutrient cycling and photosynthesis. Further, the physiology, nutrition and protection of plants and animals (including humans) is dependent on various relationships with microbes. This report will focus on the relationships between microbes and humans. And as we will see these relationships are key factors that determine whether or not we…