
- Anatomy – the study of organisms structures
- Comparative anatomy – the study of evolution of species through similarities and differences in their anatomy
- Histology – the study of 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 reactionsrequired for life to exist and function, usually a focus on the cellular level
- Biological engineering – the attempt to create products inspired by biological systems or to modify and interact with the biological systems
- 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
- Biomechanics – the study of the mechanics of living beings
- Biomedical research – the study of health and disease
- Biophysics – the study of biological processes by applying the theories and methods traditionally employed in the physical sciences
- 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
- Botany – the study of plants
- Phycology – scientific study of algae
- Plant physiology – concerned with the functioning, or physiology, of plants
- Astrobotany – the study of plants in space
- Cell biology – the study of the cell as a complete unit, and the molecular and chemical interactions that occur within a living cell
- Chronobiology – the study of periodic events in living systems
- Cognitive biology – the study of cognition
- 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)
- Gerontology – study of ageing processes
- Ecology – the study of the interactions of living organisms with one another and with the non-living elements of their environment
- Evolutionary biology – the study of the origin and descent of species over time
- Genetics – the study of genes and heredity
- Genomics – the study of genomes
- Epigenetics – the study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence
- Immunology – the study of the immune system
- 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 application of nanotechnology in biological research, and the study of living organisms and parts on the nanoscale level of organization
- Neuroscience – the study of the nervous system
- 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
- Pharmacology – the study of the interactions between drugs and organisms
- Physiology – the study of the functions and mechanisms occurring in living organisms
- Phytopathology – the study of plant diseases (also called Plant Pathology)
- Psychobiology – the application of methods traditionally used in biology to study human and non-human animals behaviour
- Quantum biology – the study of the role of quantum phenomena in biological processes
- Systems biology – the study complex interactions within biological systems through a holistic approach
- Structural biology – a branch of molecular biology, biochemistry, and biophysics concerned with the molecular structure of biological macromolecules
- Theoretical biology – the branch of biology that employs abstractions and mathematical models to explain biological phenomena
- Zoology – the study of animals, including classification, physiology, development, evolution and behaviour, including:
- Ethology – the study of animal behaviour
- 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