The biological fields of [[botany]], [[zoology]], and [[medicine]] date back to early periods of civilization, while [[microbiology]] was introduced in the 17th century with the invention of the microscope. However it was not until the 19th century that biology became a unified science; once scientists discovered commonalities between all living things it was decided they were best studied as a whole. Some key developments in the science of biology were the discovery of | The biological fields of [[botany]], [[zoology]], and [[medicine]] date back to early periods of civilization, while [[microbiology]] was introduced in the 17th century with the invention of the microscope. However it was not until the 19th century that biology became a unified science; once scientists discovered commonalities between all living things it was decided they were best studied as a whole. Some key developments in the science of biology were the discovery of |