organismsmicrobes

Microbes are microscopic organisms that encompass a broad range of life forms and biological particles. Most are unicellular, but some exist as multicellular communities or as acellular agents such as viruses. They occur in virtually every environment, from soil and water to extreme habitats and the internal systems of other organisms.

Commonly studied microbial groups include bacteria, archaea, fungi, protozoa, and algae. Bacteria and archaea are prokaryotes, lacking a nucleus, while fungi, protozoa, and algae are eukaryotes with membrane-bound organelles. Viruses, which require a host cell to reproduce, are often discussed alongside microbes but are not universally defined as living organisms.

Microbes perform essential ecological roles, including nutrient cycling (carbon, nitrogen, sulfur), decomposition, and the regulation of populations through predation and symbiosis. They also form complex communities, such as biofilms, that can alter environmental processes and host health.

In humans and other animals, microbes inhabit interfaces such as the gut, skin, and mucous membranes, contributing to digestion, immune development, and protection against pathogens. Disruptions to microbial communities can be associated with disease or health issues.

Microscopy, culture techniques, and modern sequencing technologies underpin microbiology. The field has a long history, beginning with the first observations of microorganisms by early microscopists, followed by demonstrations of germ theory and the development of antibiotics. Today, microbes are studied for medicine, industrial applications, environmental management, and fundamental biology.