Biology

Biology is the natural science that studies life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. It encompasses the study of organisms across all levels of organization, from molecules to ecosystems, and seeks to understand the interactions between organisms and their environments.

Some core concepts unify biology: cell theory states that all organisms are composed of cells and that new cells arise from existing ones; the gene theory explains how traits are inherited via DNA and gene expression; evolution by natural selection accounts for the diversity of life; metabolism covers the energy and chemical reactions that sustain life; homeostasis maintains stable internal conditions; information flow and systems thinking describe how genes, proteins, and networks govern function.

The discipline encompasses many subfields, including molecular biology, cell biology, genetics, physiology, ecology, evolution, microbiology, botany, zoology, biochemistry, and biophysics, as well as applied areas such as medicine, agriculture, and biotechnology. Research often integrates data across scales and disciplines.

Biology uses observation, experimentation, and modeling to test hypotheses. Techniques range from microscopy and sequencing to computational analysis and systems biology. Model organisms and comparative studies help reveal general principles applicable across species.

Historically, biology has deep roots in philosophy and medicine, with milestones such as cell theory, germ theory, and the modern synthesis shaping current understanding. The field underpins advances in health, environmental stewardship, and biotechnology, while also raising ethical, legal, and social considerations.