
Microorganism - Wikipedia
A microorganism, or microbe, [a] is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from …
Microbiology | Definition, History, & Microorganisms | Britannica
Dec 4, 2025 · Microorganisms are of incalculable value to Earth’s ecology, disintegrating animal and plant remains and converting them to simpler substances that can be recycled in other organisms. …
Microorganism – Definition, Types, Importance, Examples
Mar 28, 2024 · A microorganism, or microbe, is a tiny living organism that is invisible to the naked eye and can exist as single-celled entities or colonies of cells.
The Five Major Types of Microorganisms
Aug 4, 2025 · Each type of microorganism—bacteria, viruses, fungi, protozoa, and algae—occupies a unique niche in Earth’s ecosystems. Yet they do not exist in isolation.
1.1A: Defining Microbes - Biology LibreTexts
A microbe, or microorganism, is a microscopic organism that comprises either a single cell (unicellular); cell clusters; or multicellular, relatively complex organisms.
Microorganism - New World Encyclopedia
A microorganism, or microbe, is an organism (form of life) that is microscopic (too small to be seen by the unaided human eye). Microorganisms can be bacteria, fungi, archaea, or protists, but not viruses …
Microorganisms Definition - Microbiology Key Term | Fiveable
Microorganisms, also known as microbes, are tiny living organisms that are invisible to the naked eye. They include a diverse group of microscopic life forms such as bacteria, archaea, fungi, protists, and …
MICROORGANISM Definition & Meaning - Merriam-Webster
Dec 5, 2016 · The meaning of MICROORGANISM is an organism (such as a bacterium or protozoan) of microscopic or ultramicroscopic size.
What are Microbes? - University of Utah
Bacteria are microscopic, single-celled organisms that have no nucleus and a cell wall made of peptidoglycan. Bacteria are the direct descendents of the first organisms that lived on Earth, with …
Microorganism - an overview | ScienceDirect Topics
Microorganisms are present virtually in every habitat on our planet, and responsible for numerous of functions. Microorganisms in their natural habitat coexist in mixed communities and form complex …