What Is Biology? Research Areas, Funding, and Career Paths

Biology is the scientific study of life: the structure, function, growth, origin, evolution and distribution of living organisms, from single molecules and cells through whole organisms to populations, communities and entire ecosystems. It is one of the largest and most heavily funded areas of scientific research, and it is also one of the most administratively complex — biology research routinely involves human-subjects and animal-welfare oversight, large multi-institutional data consortia, and a funding landscape spread across several federal agencies and private foundations, on top of the science itself. This guide gives a genuine, thorough answer to what biology studies and how it developed as a science, covers its major branches, and adds the research-administration layer generic overviews leave out: who actually funds biology research, the methods and tools the field relies on, and typical career and training paths into it.

What Is Biology?

Biology is the natural science concerned with living organisms and the processes that define life: growth, metabolism, reproduction, response to stimuli, and, over longer timescales, adaptation and evolution. The name comes from the Greek bios (life) and logia (study of), and as a formal discipline it asks a small number of interlocking core questions:

• What is life, and what distinguishes living from non-living matter? — the search for a working definition of life centers on properties such as cellular organization, metabolism, homeostasis, growth, reproduction, heredity and the capacity to evolve.
• How do organisms function? — the physiological, biochemical and molecular processes that keep an organism alive, from a single bacterial cell to a multicellular animal or plant.
• How is biological information transmitted and expressed? — how genetic information stored in DNA is copied, passed to offspring, and read out to build and operate an organism.
• How does life change over time? — the mechanisms of evolution (natural selection, genetic drift, mutation, gene flow) that explain both the diversity of life and the relationships between species.
• How do organisms interact with each other and their environment? — the ecological relationships that connect individual organisms into populations, communities and ecosystems.

Biologists study these questions across a wide range of scales — molecular, cellular, organismal, population and ecosystem — and use a correspondingly wide range of methods, from controlled laboratory experiments and molecular assays to field observation, comparative anatomy, and large-scale computational and statistical analysis. What unifies the discipline is not a single method but a shared subject: life itself, in all its structural and functional forms.

How Biology Developed as a Science

Biology’s roots reach back to ancient natural history — Aristotle’s systematic descriptions and classifications of animals in the 4th century BCE are often cited as the earliest attempt to study living things as a coherent subject rather than isolated curiosities. The discipline took its modern shape gradually, through a series of foundational developments:

• Classification and taxonomy: Carl Linnaeus’s 18th-century system of binomial nomenclature (genus plus species) gave biology a standardized way to name and organize the diversity of life, a system still in use today.
• Cell theory: the 1830s–1840s work of Matthias Schleiden and Theodor Schwann established that the cell is the basic structural and functional unit of all living organisms.
• Evolution by natural selection: Charles Darwin’s and Alfred Russel Wallace’s independently developed theory, published jointly in 1858 and expanded in Darwin’s 1859 On the Origin of Species, provided the unifying mechanism explaining how species change and diversify over time.
• Heredity: Gregor Mendel’s mid-19th-century experiments with pea plants established the basic statistical rules of trait inheritance, though the work went largely unrecognized until it was rediscovered around 1900.
• Germ theory: Louis Pasteur’s and Robert Koch’s late-19th-century work established that specific microorganisms cause specific diseases, founding modern microbiology and medicine.
• The modern synthesis: in the 1930s–1940s, evolutionary biology and Mendelian genetics were combined into a single coherent framework, resolving an earlier split between geneticists and naturalists over how evolution actually worked.
• The molecular revolution: James Watson and Francis Crick’s 1953 description of the double-helix structure of DNA, built on X-ray diffraction data from Rosalind Franklin and Maurice Wilkins, gave biology a physical, molecular basis for heredity and opened the modern era of molecular biology.
• The genomic and computational era: the completion of the Human Genome Project in the early 2000s and the subsequent collapse in DNA-sequencing cost shifted much of biology toward genome-scale, data-intensive and computational approaches, giving rise to genomics, bioinformatics and systems biology as major growth areas within the field.

How Biology Relates to Neighboring Disciplines

Biology sits at the center of a cluster of related sciences, and the boundaries between them are genuinely blurry rather than sharply defined:

• Chemistry supplies the molecular and reaction-level foundation for biochemistry and molecular biology; see this site’s companion guide, What Is Chemistry?, for how the two fields divide up the study of matter and its transformations.
• Physics underlies biophysics and structural biology — the physical forces and imaging techniques used to study how biological molecules and systems behave; see What Is Physics?.
• Psychology and neuroscience overlap with biology wherever behavior and cognition are studied at the level of neurons, hormones and genetics rather than purely at the level of mind and behavior; see What Is Psychology? and this site’s discipline guide on What Is Neuroscience?.
• Computer science increasingly underpins biology through bioinformatics and computational biology, the data-analysis backbone of modern genomics and systems biology; see What Is Computer Science?.
• Medicine, agriculture and environmental science are largely applied extensions of biological knowledge — medicine applies physiology, immunology and genetics to human health; agriculture applies genetics, physiology and ecology to crops and livestock; environmental science applies ecology and earth systems science to environmental problems.

Because of this overlap, many practicing scientists in genetics, molecular biology, biochemistry, ecology, immunology, neuroscience, virology and other life-science fields describe themselves as biologists first and specialists second — the branches below are best understood as areas of emphasis within one broad discipline rather than fully separate sciences.

Major Branches of Biology

Biology is not one uniform activity. Researchers who call themselves biologists typically work within one or more of the following major branches:

• Molecular biology — studies biological processes at the level of molecules: DNA, RNA, proteins, and how they interact to carry out cellular functions. See this site’s guide, What Is Molecular Biology?.
• Cell biology — studies the structure, function and life cycle of cells, the basic unit of life common to all organisms.
• Genetics — studies genes, heredity and genetic variation. See What Is Genetics?.
• Biochemistry — studies the chemical processes within and related to living organisms. See What Is Biochemistry?.
• Physiology — studies how organisms and their organs, tissues and cells function, individually and as integrated systems.
• Anatomy and morphology — studies the structure and form of organisms and their parts.
• Microbiology — studies microorganisms: bacteria, archaea, fungi and protists (viruses are often studied within microbiology as well, though they are not classified as living cells; see What Is Virology? for the dedicated field studying them).
• Botany — the biology of plants: their structure, growth, reproduction, physiology and classification.
• Zoology — the biology of animals, covering their structure, physiology, behavior and classification across the animal kingdom.
• Ecology — studies how organisms interact with each other and their environment, at the population, community and ecosystem level. See What Is Ecology?.
• Evolutionary biology — studies how species change over time through natural selection, genetic drift, mutation and other mechanisms, and the relationships between species.
• Developmental biology — studies how a single fertilized cell develops into a complex, differentiated organism.
• Immunology — studies the immune system and how organisms defend against pathogens and other threats. See What Is Immunology?.
• Neuroscience — studies the nervous system, from individual neurons to behavior and cognition. See What Is Neuroscience?.
• Structural biology — determines the three-dimensional shapes of biological macromolecules (proteins, nucleic acids) to understand how their structure produces their function.
• Systems biology — studies biological systems as integrated networks of genes, proteins and metabolic pathways rather than as isolated parts, typically using computational modeling.
• Computational biology and bioinformatics — develops and applies computational methods to analyze large-scale biological data, from genome sequences to protein structures.
• Marine and aquatic biology — studies organisms and ecosystems in oceans, lakes and rivers.
• Taxonomy and systematics — classifies organisms and studies the evolutionary relationships between them.
• Conservation biology — applies biological and ecological knowledge to the protection and management of biodiversity and threatened species.

Epidemiology and biostatistics are closely related, quantitative fields that apply biological and statistical methods to population-level health questions; see this site’s guides on What Is Epidemiology? and What Is Biostatistics? for how they extend biological methods to human-population research specifically.

How Biology Research Is Funded

Biology is one of the largest and most diversely funded areas of scientific research, spanning basic, disease-focused, agricultural, environmental and infrastructure funding streams. In the United States, several distinct federal funders are active:

• The National Institutes of Health (NIH) is the largest single funder of biomedical and biological research. NIGMS (the National Institute of General Medical Sciences) has the broadest explicit mission to fund basic, foundational biology — molecular, cellular and structural — independent of any specific disease focus. Beyond NIGMS, most of NIH’s other institutes and centers (NCI, NIAID, NIDDK, NICHD and others) fund biology research relevant to their own disease or organ-system mandate, since basic biological knowledge underlies nearly every area of human health NIH studies.
• The National Science Foundation (NSF) funds fundamental biology primarily through its Directorate for Biological Sciences (BIO), which describes its mission as funding research “from molecules to ecosystems.” BIO is organized into divisions covering different levels of biological organization, including molecular and cellular biosciences and environmental biology, among others.
• The U.S. Department of Agriculture’s National Institute of Food and Agriculture (USDA NIFA) funds biology research applied to agriculture — plant and animal biology, breeding, and agricultural genomics.
• The Department of Energy (DOE) Office of Science funds biological research and infrastructure relevant to energy and environmental science, including genomics and large-scale sequencing capacity.

Outside the federal government, a small number of major private foundations are well-established funders across broad areas of biology. The Howard Hughes Medical Institute (HHMI) funds individual biomedical investigators, many working in core areas of biology, through its distinctive person-not-project funding model. In the UK, the Wellcome Trust is one of the world’s largest funders of biological and biomedical research. Numerous other foundations fund biology research within a specific disease area, taxon or ecosystem, typically alongside federal funding rather than as a standalone funding stream.

Because so much modern biology research is organized around large collaborative resources rather than single-investigator labs, it raises research-administration questions that a purely disciplinary overview would miss. Large biobanks and genome-sequencing consortia routinely produce papers with hundreds of contributing scientists, which raises real authorship and credit questions distinct from a traditional single-lab study — see this site’s guide on how large genomics consortia and biobank studies credit contributors. Biological specimen collections themselves also require careful consent governance; see this site’s comparison of broad, tiered and dynamic biobank specimen consent models for how that gets handled in practice.

Common Research Methods and Tools in Biology

The specific techniques vary enormously by branch and by the scale being studied, but biology research routinely draws on a common toolkit:

• Microscopy — from basic light microscopy to electron and confocal microscopy, used to visualize structures ranging from whole cells down to individual macromolecules.
• Molecular and genomic techniques — DNA/RNA sequencing, polymerase chain reaction (PCR), and related assays used to read, amplify and analyze genetic material; sequence data is typically deposited in public repositories such as GenBank for sharing and reuse.
• Cell culture — growing cells outside their original organism under controlled laboratory conditions, foundational to molecular and cell biology, immunology and much of biomedical research.
• Model organisms — biology research relies heavily on a small set of well-characterized species (mice, zebrafish, the fruit fly Drosophila, the roundworm C. elegans, and yeast, among others) whose biology is comparatively easy to manipulate and interpret; see this site’s comparison of the major model organism genome databases for how their data is organized and shared. Research using live vertebrate animals is subject to institutional oversight; see this site’s guide to IACUC and animal research oversight for how that approval process works.
• Field observation and sampling — ecology, botany, zoology and marine biology depend heavily on data collected directly in natural environments, from population surveys to specimen collection; standardized specimen-occurrence data is commonly shared using conventions such as Darwin Core occurrence IDs.
• Biostatistics and computational analysis — the large, often high-dimensional datasets modern biology produces (a single genome sequence is several gigabytes of raw data) require substantial statistical and computational expertise to analyze rigorously.
• Structural and imaging methods — X-ray crystallography, cryo-electron microscopy, and mass spectrometry are used to determine the structure and composition of biological molecules.

Career and Training Pathways

Research careers in biology typically follow the standard life-sciences academic pathway: an undergraduate degree in biology or a related field, followed by a PhD program (commonly five to six years in the US) combining coursework, laboratory rotations, a qualifying examination, and original dissertation research within a chosen branch of the field. Most academic research careers continue with one or more postdoctoral research positions before a scientist leads an independent laboratory. Biology PhD training is offered both through general biology or biological sciences graduate programs and through more specialized programs (molecular biology, ecology and evolutionary biology, neuroscience, and others), depending on the institution and the student’s area of focus.

A PhD-track research career is far from the only path into the field. Biology graduates and postgraduates also work in biotechnology and pharmaceutical research and development, clinical and diagnostic laboratories, healthcare and allied health professions, science and environmental policy, conservation and natural-resource management, science writing and communication, secondary and higher education, and research administration roles supporting biology research programs directly.

Two long-established organizations are widely known focal points for the field in the US: the American Institute of Biological Sciences (AIBS), a broad professional and scientific society representing biology across its many subfields, and the American Society for Cell Biology (ASCB), focused specifically on cell biology research. Many of biology’s individual branches also have their own dedicated professional societies, discussed in this site’s guides to those specific fields.

Frequently Asked Questions

What is biology in simple terms?

Biology is the scientific study of living things — how they are built, how they function, how they reproduce and pass on traits, and how they change over time and interact with their environment. It spans everything from individual molecules inside a cell to entire ecosystems.

What are the main branches of biology?

The major branches include molecular biology, cell biology, genetics, biochemistry, physiology, anatomy, microbiology, botany, zoology, ecology, evolutionary biology, developmental biology, immunology, neuroscience, structural biology, systems biology, computational biology/bioinformatics, marine biology, taxonomy/systematics, and conservation biology — see the branches section above for what each one covers.

What is the difference between biology and biochemistry?

Biology is the broad study of living organisms at every scale, from molecules to ecosystems. Biochemistry is a specific branch of biology (and of chemistry) that focuses on the chemical processes occurring within and related to living organisms — it is one of biology’s core branches, not a separate discipline.

Who funds biology research?

In the US, major federal funders include NIH (particularly NIGMS for basic, non-disease-specific biology, plus disease-focused institutes funding biology relevant to their own remit), NSF’s Directorate for Biological Sciences, USDA’s NIFA for agricultural biology, and DOE for biological research infrastructure. Private funders active across many areas of biology include organizations such as HHMI and, internationally, the Wellcome Trust.

What jobs can you get with a biology degree?

Common paths include academic and industry research (typically requiring a PhD for independent research roles), clinical and diagnostic laboratory work, biotechnology and pharmaceutical R&D, healthcare and allied health professions, conservation and environmental work, science policy, science writing and communication, teaching, and research administration roles supporting biology research programs.

Related Guides

This guide is part of a series covering major scientific disciplines from a research-administration perspective — see the overview guide to the branches of science for how biology relates to neighboring fields, and these companion discipline guides: What Is Genetics?, What Is Ecology?, and What Is Chemistry?.