Biology is the study of life in general — every living thing, at every scale. Microbiology is one of its branches, dealing with organisms too small to see unaided: bacteria, archaea, fungi, protists and viruses. All microbiology is biology; most biology is not microbiology.
The core difference
A field and one of its subfields, distinguished by scale.
- biology — the study of living organisms of every kind.
- microbiology — the study of microscopic organisms.
The other main branches
Biology divides many ways: botany (plants), zoology (animals), genetics (heredity), ecology (organisms and environments), anatomy (structure), physiology (function). These overlap heavily — a microbiologist studying bacterial genes is doing genetics too.
The viruses question
Microbiology conventionally includes virology, though whether viruses are alive at all is genuinely contested: they carry genetic material but cannot reproduce without a host cell. The field includes them for practical reasons rather than because the definitional question is settled.
Frequently asked questions
Is microbiology part of biology?
Yes. It is the branch dealing with organisms too small to see without a microscope.
Does microbiology include viruses?
Conventionally yes, through virology — though whether viruses count as living is still debated, since they cannot reproduce without a host.
What are the main branches of biology?
Botany, zoology, genetics, ecology, anatomy, physiology and microbiology among others, all of which overlap considerably.