Biology

Biology is the natural science that studies living organisms and the processes of life. It examines the structure of organisms, how they function, their growth, reproduction, and their relationships with their environment. The term derives from two Greek words: 'bios', meaning life, and 'logos', meaning science or study.

Biology operates at multiple levels of organization: from molecules and cells up to tissues, organs, whole organisms, populations, and ecosystems. The method rests on observation, controlled experiment, and testable hypothesis.

Fundamental principles

Central ideas in biology include cell theory (all living things consist of one or more cells), genetics (which explains how traits pass from generation to generation), and evolution (which explains the diversity of species). There is also the principle of homeostasis—the ability of organisms to maintain a stable internal environment—and metabolism.

Genetic information is stored in DNA, a long molecule that carries the instructions for building proteins. Mutations and natural selection form the basis of how species change over time.

Branches

Biology has many branches. Botany studies plants, zoology studies animals. Microbiology examines microscopic life such as bacteria. Genetics works with heredity, ecology with the relationships between organisms and their environment. There is also physiology (how bodies function), anatomy (bodily structure), and molecular biology. Newer fields such as bioinformatics use computers to analyze large amounts of genetic data.

History and application

Study of living things is ancient, but biology became a systematic science in recent centuries, especially after the development of the microscope and work on classifying species and understanding evolution. The discovery of DNA's structure in the twentieth century opened a new chapter. Biology's results are now applied in medicine, agriculture, industry, and environmental management.