What are the 3 main branches of Biology?

Biology is one of the broadest disciplines of science. Biology came from the Greek word bio meaning life and logos meaning study. Under biology are numerous sub-disciplines that focus on specific organisms or phenomena relating to organisms and their lives. But what are the three main branches of biology and what are the subdisciplines under them? Continue reading to find out.

What are the three main branches of Biology?

The three main branches of biology are the following:

  • Botany
  • Zoology
  • Microbiology


Botany is the science of plants. It is one of the main branches of biology as it tackles topics related to the kingdom Plantae and often intersects with other subdisciplines like ecology, genetics, and many more.

The Greek philosopher Theophrastus was one of the early Botanists of the world and also called the “Father of Botany” because of his significant contributions to the studies of plants.

Botany and the study of plants’ structure, properties, and biochemical processes are further divided into four systematic studies. These are morphology, physiology, ecology, and systematics. 

Morphology also known as phytomorphology is concerned with the external or physical form and structure of plants to describe, categorize, and distinguish which group it homogenously belongs to.

Physiology is a division of botany that studies the plant’s function, process, behavior, and overall physiological components including metabolism and reproduction as it grows and matures.

Ecology or plant ecology is a subdiscipline of botany and ecology that tackles the relationship of plants to other plants, organisms, and other abiotic components of the environment.

The following are a few of the subdisciplines under botany:

  • Agriculture
  • Bacteriology
  • Ethnobiology
  • Dendrology
  • Phenology
  • Paleobotany
  • Plant anatomy
  • Agroforestry


Zoology is the science of animals. It is one of the main branches of biology because of its broad subject area. Zoology focuses on animals’ physiology, anatomy, organization, structure, evolution, classification, and distribution. 

Zoology is concerned with the animal’s structure from the molecular level to the individual characteristics to their constituent parts and their relationship to their environment and other animals.

Aristotle an ancient Greek philosopher is one of the pioneering contributors to this discipline because of his efforts to analyze and classify animals by recognizing their similarities with different organisms.

First, he studied animals with the same reproduction process then he classified them into their natural habitat. For his work, Aristotle was credited for creating a system for organizing animals in the fourth century.

Zoology finally took off in the 12th century as a discipline of science and its early works focused on identifying and describing the body structure of animals to further classify them into their groups.

Because of this, another discipline emerge as a science of classifying organisms according to a system called the binomial system of nomenclature developed by Swedish botanist Carolus Linnaeus.

Humans are also studied in the branch of Zoology as they belong to the kingdom of animals, in the phylum chordate, class Mammalia, order primates, family of Hominidae, genus homo, and specie of sapiens.

Few subdisciplines under zoology are the following:

  • Entomology
  • Genetics
  • Mammalogy
  • Paleontology
  • Embryology
  • Zoogeography
  • Arachnology
  • Paleozoology
  • Animal Physiology


Microbiology is the science of microorganisms. Microbiology is one of the main branches of biology because it is concerned with all organisms that are invisible to the naked eye and their structure, function, and classification. 

Organisms characterize by their cells which are either unicellular, multicellular, or even with no cells called acellular. These organisms include fungi, bacteria, algae, and even viruses that lack other components of microorganisms.

Microbiology is a broad discipline of biology as it encompasses numerous subdisciplines in biology including bacteriology, virology, mycology, immunology, and parasitology.

The abundance of these microorganisms or microbes made their study so fascinating as it has been proven that there are more microbes inside our body than the number of our body cells.

Some of these microbes are good as they aid several processes inside our bodies like digesting food and absorbing nutrients, and they produce several vitamins in the intestinal tract.

Microbiology has two main branches; pure and applied microbiology. These two main branches emerge because of the need to differentiate the foundational study of microorganisms from their application to different processes.

Pure microbiology is concerned with the fundamental and deeper understanding of microorganisms by conducting a research study on a specific group of microbes.

In pure microbiology, the end goal is better to understand microorganisms and the phenomenon they undergo through an in-depth examination and investigation.

Applied microbiology uses the foundational knowledge about microbes and utilizes them in various scientific processes for different fields and industries.

All in all, applied microbiology centers on how these microbes that we know of can be applied and make use of to produce products such as vaccines, and medicines, that will be advantageous to humans in the long run.

Different subdisciplines under microbiology are the following:

  • Astromicrobiology
  • Cellular microbiology
  • Microbial genetics
  • Microbial physiology
  • Immunology
  • Protozoology
  • Bacteriology
  • Mycology
  • Phycology/algology
  • Virology
  • Nematology
  • Agricultural microbiology
  • Plant microbiology
  • Soil microbiology
  • Veterinary microbiology
  • Water microbiology
  • Aero microbiology
  • Biotechnology


Biology is one of the broadest disciplines of natural science and is viewed as the most intricate discipline because of all the life forms to derive research and study from the origins, morphology, anatomy, physiology, distribution, and behavior. 

It is often the reason why some of these fields are interdisciplinary sciences especially its three main branches; Botany, Zoology, and Microbiology.

Biology and its main branches have been one of the foundations of the knowledge we have of our modern world today. The advantage we gain from these disciplines brought about some of the most important discoveries and advancements we have today.

Frequently Asked Questions (FAQs): what are the 3 main branches of biology?

Who is the father of biology?

Taught by Plato, Aristotle is considered the father of biology. During the Classical period in Ancient Greece, he founded the Peripatetic school of philosophy, Lyceum.

What are the seven types of biologists?

The seven types of biologists are the following: 

  • Ecologist.
  • Biological engineer.
  • Biostatistician.
  • Forensic biologist.
  • Microbiologist.
  • Marine biologist.
  • Wildlife biologist.

What is a cell?

The cell is known to be the smallest unit of life. It has three major parts; the cell membrane, the nucleus, and the cytoplasm. Every living organism is composed of cells whether unicellular or multicellular.


Branches Of Biology Encyclopedia Articles https://www.britannica.com/browse/Branches-Biology 

Woese, C.R., 2004. A new biology for a new century. Microbiology and molecular biology reviews, 68(2), pp.173-186.

Lindley, J. (1839). An introduction to botany. Longman, Orme, Brown, Green, and Longmans.

BioExplorer.net. Branches of Biology / Divisions of Biology. Bio Explorer. https://www.bioexplorer.net/divisions_of_biology/

Tortora, G. J., Funke, B. R., & Case, C. L. (2018). Microbiology: an introduction. Pearson.

Branches of Biology and Their Meaning LEEFRANCESEMERYSEP 27, 2016 https://owlcation.com/stem/Branches-of-Biology-and-its-Meaning 

Zucker, A. (2019). Zoology. In A Companion to Byzantine Science (pp. 261-301). Brill.

Branches of biology. (2021, March 1). Biology Online. https://www.biologyonline.com/dictionary/branches-of-biology