The main branches of biology include cellular and molecular biology, physiology and developmental biology as well as genetics, zoology, microbiology and ecology. There are numerous sub-branches of biology, which include entomology and comparative anatomy. These sub-branches typically concentrate on the study of animals, evolution or the environment.
Biology is a natural science concerned with the study of life and organisms. Modern biology is a vast field that encompasses many sub-disciplines. Basic biological concepts, such as recognizing the cell as the basic unit of life and evolution as the process through which species are created and altered, serve to unify the many different branches of modern biology. Many sub-branches of biology can be defined based on the scale, methods and types of organisms studied.
While modern biology is a relatively new science, the study of living organisms has been ongoing since ancient times. Natural philosophy was a subject of study for ancient Egypt, Mesopotamia and China. The invention of the microscope created many new developments that would impact the science of biology, including the creation of the microbiology sub-discipline. Charles Darwin's theories regarding evolution and natural selection quickly became central axioms within the rapidly growing field of biology. More recently, discoveries related to DNA and the role chromosomes play in heredity have had far reaching impacts on many branches of biology.