Microbiology is the study of organisms and viruses too small to be seen by the unaided eye. Microbiologists study all aspects of these organisms, including what they are, their lifecycle and metabolic capacity, their distribution in nature, and their relationship to each other and to other living things. Microbial engineering uses our current understanding of these organisms to develop new species with applications in (for example) bioremediation, alternative energy production, or pharmaceutical science.