Understanding the emergence of microbiology sheds light on the nature of the science itself and is therefore often the starting point of most classes. Early scientists had hypothesized about the existence of microorganisms centuries before their existence was actually confirmed, but it took the discovery of the microscope to to provide actual documentation. It was Antonie van Leeuwenhoek who is credited with developing the first single-lens microscope in 1676 which allowed him to view bacteria and other microorganisms. Actually, however, several others before him also documented viewing microorganisms through simple microscopes. Regardless, the work of Louis Pasteur and Robert Koch is credited with giving rise to the science of microbiology. Courses usually cover many specifics of these developments in detail.
As microscopes became more complex and the body of knowledge expanded, microbiology became increasingly complex. Learning the specifics of this complexity is a cornerstone of microbiology classes. Students are responsible for knowing the taxonomy of microorganisms, including algae, archaea, bacteria, fungi and yeasts, parasites, protozoa and viruses. Students are also taught there are additional microbes yet to be discovered.
Another basic course objective is for students to learn the classification of these microbes as either prokaryotes (archaea and bacteria) or eukaryotes (most plants and animals, including humans) and understand the significance of the distinctions. The differences between bacteria and viruses are covered, since technically viruses aren't classified as living organisms, though they are considered microorganisms. Much of the work within microbiology is focused on bacteria and viruses.
As more has become known about microbiology, new areas of specialization have emerged. Students are made aware of these branches and provided varying amounts of background information. These branches include bacteriology (bacteria), immunology (immune system), mycology (fungi), parasitology (parasites), phycology (algae) and protozoology (protozoa). They also study how these branches have been incorporated into other fields of study, such as immunology.
Microbiology classes almost always entail lab work in which many of the microorganisms are viewed and studied firsthand. This includes learning the operation of the microscope and the proper staining of microbes for examination as well as learning about aseptic technique and the proper culturing of microorganisms. This portion of the course is where students are also apprised of the latest microbiological lab methods and research.
Courses address the application of microbiology in different areas, having the added benefit of exploring career options. This can include exploring how microorganisms are dealt with in the food industry to avoid spoilage and food-borne illness or bolster the properties of food such as with probiotics. Microbes' role in the pharmaceutical industry, in wastewater treatment science and in managing human disease are just some of the different applications explored. This part of the course frequently also discusses future trends and cutting-edge research.