The vast majority of Earth's biodiversity is microbial. Microorganisms are directly involved in the ecosystem services on which all of life depends. They interact intimately with other organisms and yet we know much less about their biodiversity than we do for plants and animals. Our lack of understanding of the interactions and feedbacks of microbial biodiversity is troubling, given the high rates of environmental change that the Earth is currently experiencing, including man-made global climate change. Satisfies one of three required modules for the Integrative Experience requirement for BA-MicBio or BS-MicBio majors.