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Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Use this tag for general biology questions, but also use more specific life science tags to accompany this one if applicable.


Biology is a vast subject containing many subdivisions, topics, and disciplines. Among the most important topics are five unifying principles that can be said to be the fundamental axioms of modern biology:

  1. Cells are the basic unit of life
  2. New species and inherited traits are the product of evolution
  3. Genes are the basic unit of heredity
  4. An organism regulates its internal environment to maintain a stable and constant condition
  5. Living organisms consume and transform energy.


Subdisciplines of biology are recognized on the basis of the scale at which organisms are studied and the methods used to study them: biochemistry examines the rudimentary chemistry of life; molecular biology studies the complex interactions of systems of biological molecules; cellular biology examines the basic building block of all life, the cell; physiology examines the physical and chemical functions of the tissues, organs, and organ systems of an organism; and ecology examines how various organisms interact and associate with their environment.

A more comprehensive list is the following:

  • Anatomy
  • Arachnology
  • Astrobiology
  • Botany
  • Biochemistry
  • Biogeography
  • Bioinformatics
  • Biophysics
  • Cell biology
  • Cytology
  • Dendrology
  • Developmental biology
  • Ecology
  • Entomology
  • Ethology
  • Evolutionary biology
  • Embryology
  • Genetics / Genomics
  • Herpetology
  • Histology
  • Human biology / Anthropology / Primatology
  • Ichthyology
  • Limnology
  • Malacology
  • Mammalogy
  • Marine biology
  • Microbiology / Bacteriology
  • Molecular biology
  • Mycology / Lichenology
  • Nematology
  • Neurobiology / Neuroscience
  • Ornithology
  • Parasitology
  • Palaeontology
  • Phycology
  • Phylogenetics
  • Physiology
  • Plant pathology
  • Taxonomy
  • Virology
  • Zoology