Biology is a natural science concerned with the study of living organisms, life and living material, including the structure, function, growth, energy, evolution, distribution, identification and taxonomy of living organisms.

The main branches of biology:

Aerobiology – the study of airborne organic particles

Agriculture – the study of producing crops and raising livestock, with an emphasis on practical applications

Anatomy – the study of form and function, in plants, animals, and other organisms, or specifically in humans

Histology – the study of cells and tissues, a microscopic branch of anatomy

Astrobiology (also known as exobiology, exopaleontology, and bioastronomy) – the study of evolution, distribution, and future of life in the universe

Biochemistry – the study of the chemical reactions required for life to exist and function, usually a focus on the cellular level

Bioengineering – the study of biology through the means of engineering with an emphasis on applied knowledge and especially related to biotechnology

Biogeography – the study of the distribution of species spatially and temporally

Bioinformatics – the use of information technology for the study, collection, and storage of genomic and other biological data

Biolinguistics – the study of the biology and evolution of language.

Biomathematics (or Mathematical biology) – the quantitative or mathematical study of biological processes, with an emphasis on modeling

Biomechanics – often considered a branch of medicine, the study of the mechanics of living beings, with an emphasis on applied use through prosthetics or orthotics

Biomedical research – the study of health and disease
Pharmacology – the study and practical application of preparation, use, and effects of drugs and synthetic medicines

Biomusicology – the study of music from a biological point of view.

Biophysics – the study of biological processes through physics, by applying the theories and methods traditionally used in the physical sciences

Biosemiotics – the study of biological processes through semiotics, by applying the models of meaning-making and communication

Biotechnology – the study of the manipulation of living matter, including genetic modification and synthetic biology

Synthetic biology – research integrating biology and engineering; construction of biological functions not found in nature
Building biology – the study of the indoor living environment
Botany – the study of plants

Cell biology – the study of the cell as a complete unit, and the molecular and chemical interactions that occur within a living cell

Cognitive biology – the study of cognition as a biological function

Conservation biology – the study of the preservation, protection, or restoration of the natural environment, natural ecosystems, vegetation, and wildlife

Cryobiology – the study of the effects of lower than normally preferred temperatures on living beings

Developmental biology – the study of the processes through which an organism forms, from zygote to full structure

Embryology – the study of the development of embryo (from fecundation to birth)

Ecology – the study of the interactions of living organisms with one another and with the non-living elements of their environment

Environmental biology – the study of the natural world, as a whole or in a particular area, especially as affected by human activity

Epidemiology – a major component of public health research, studying factors affecting the health of populations

Evolutionary biology – the study of the origin and descent of species over time
Genetics – the study of genes and heredity.

Epigenetics – the study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence

Hematology (also known as Haematology) – the study of blood and blood-forming organs.

Integrative biology – the study of whole organisms
Limnology – the study of inland waters

Marine biology (or Biological oceanography) – the study of ocean ecosystems, plants, animals, and other living beings

Microbiology – the study of microscopic organisms (microorganisms) and their interactions with other living things

Bacteriology – the study of bacteria

Mycology – the study of fungi

Parasitology – the study of parasites and parasitism

Virology – the study of viruses and some other virus-like agents
Molecular biology – the study of biology and biological functions at the molecular level, some cross over with biochemistry

Nanobiology – the study of how nanotechnology can be used in biology, and the study of living organisms and parts on the nanoscale level of organization

Neurobiology – the study of the nervous system, including anatomy, physiology and pathology

Population biology – the study of groups of conspecific organisms, including …
Population ecology – the study of how population dynamics and extinction

Population genetics – the study of changes in gene frequencies in populations of organisms

Paleontology – the study of fossils and sometimes geographic evidence of prehistoric life

Pathobiology or pathology – the study of diseases, and the causes, processes, nature, and development of disease

Physiology – the study of the functioning of living organisms and the organs and parts of living organisms

Phytopathology – the study of plant diseases (also called Plant Pathology)

Psychobiology – the study of the biological bases of psychology

Quantum biology – the study of quantum mechanics to biological objects and problems.

Sociobiology – the study of the biological bases of sociology

Structural biology – a branch of molecular biology, biochemistry, and biophysics concerned with the molecular structure of biological macromolecules

Zoology – the study of animals, including classification, physiology, development, and behavior, including …

Ethology – the study of animal behavior
Entomology – the study of insects
Herpetology – the study of reptiles and amphibians
Ichthyology – the study of fish
Mammalogy – the study of mammals
Ornithology – the study of birds