History of biology

History
Ernst Haeckel's Tree of Life (1879)
Although biology in its modern form is a relatively recent development, sciences related to and included within biology have been studied since ancient times. Natural philosophy was studied as early as the ancient civilizations of Mesopotamia, Egypt, the Indian subcontinent, and China. However, the origins of modern biology and its approach to the study of nature are most often traced back to ancient Greece.[10]While the formal study of medicine dates back to Hippocrates, it was Aristotle who contributed most extensively to the development of biology. Especially important are his History of Animals and other works where he showed naturalist leanings, and later more empirical works that focused on biological causation and the diversity of life. Aristotle's successor at the Lyceum, Theophrastus, wrote a series of books onbotany that survived as the most important contribution of antiquity to botany, even into the Middle Ages. Significant advances in the study and development of biology were promoted through the efforts of suchMuslim physicians as the Afro-Arab scholar al-Jahiz (781–869) in zoology,[11] the Kurdish biologist Al-Dinawari (828–896) in botany,[12] and the Persian physician Rhazes (865–925) in anatomy and physiology. These philosophers elaborated on, expanded, and improved the Greek biological theories and systematics. Medicine was especially well studied by Islamic scholars working in Greek philosopher traditions, while natural history drew heavily on Aristotelian thought, especially in upholding a fixed hierarchy of life.
Biology began to quickly develop and grow with Antony van Leeuwenhoek's dramatic improvement of the microscope. It was then that scholars discovered spermatozoa, bacteria, infusoria and the sheer strangeness and diversity of microscopic life. Investigations by Jan Swammerdam led to new interest inentomology and built the basic techniques of microscopic dissection and staining.[13]
Advances in microscopy also had a profound impact on biological thinking itself. In the early 19th century, a number of biologists pointed to the central importance of the cell. In 1838 and 1839, Schleiden and Schwann began promoting the ideas that (1) the basic unit of organisms is the cell and (2) that individual cells have all the characteristics of life, though they opposed the idea that (3) all cells come from the division of other cells. Thanks to the work of Robert Remak and Rudolf Virchow, however, by the 1860s most biologists accepted all three tenets of what came to be known as cell theory.[14]
Meanwhile, taxonomy and classification began to present a focal point in the study of natural history. Carolus Linnaeus published a basictaxonomy for the natural world in 1735 (variations of which have been in use ever since), and in the 1750s introduced scientific names for all his species.[15] Georges-Louis Leclerc, Comte de Buffon, treated species as artificial categories and living forms as malleable—even suggesting the possibility of common descent. Though he was opposed to evolution, Buffon is a key figure in the history of evolutionary thought; his work would influence the evolutionary theories of both Lamarck and Darwin.[16]
Serious evolutionary thinking originated with the works of Jean-Baptiste Lamarck. However, it was the British naturalist Charles Darwin, combining the biogeographical approach of Humboldt, the uniformitarian geology of Lyell, Thomas Malthus's writings on population growth, and his own morphological expertise, that created a more successful evolutionary theory based on natural selection; similar evidence led Alfred Russel Wallace to independently reach the same conclusions.[17]
The discovery of the physical representation of heredity came along with evoluttionary principles and population genetics. In the 1940s and early 1950s, experiments pointed to DNA as the portion of chromosomes (and perhaps other nucleoproteins) that held genes. A focus on new model organisms such as viruses and bacteria, along with the discovery of the double helical structure of DNA in 1953, marked the transition to the era of molecular genetics. Since the 1950s to present times, biology has been extensively defined in the molecular form. The DNA code was cracked by Har Gobind Khorana, Robert W. Holley and Marshall Warren Nirenberg after DNA was proven to be composed solely of codons. Finally, the Human Genome Project was launched in 1990 as an attempt to map out the general human genome. This project was essentially completed in 2003, with further analysis still being published. The Human Genome Project was the first step in the globalized effort to incorporate accumulated knowledge of biology into a functional, molecular definition of the human body.