Biology

Biology comes from the Greek word for life, bis, and the Greek word for thought or reasoning, logos. It denotes the science that studies life, the properties and processes that sustain life, the evolutionary history of life, and particular living organisms. It is a science of enormous diversity, breadth, and heterogeneity unified only by the conceptual framework provided by the theory of evolution. Indeed, as famously noted in 1973 by the Russian evolutionary geneticist Theodosius Dobzhansky (1900–1975), "Nothing in biology makes sense except in the light of evolution"—a quote now replicated in so many university-level textbooks that it is almost a dictum in modern biology.

One reason for the diversity of biology comes from the staggering diversity of organisms that can be considered living. These range from viruses, bacteria, and fungi to plants and animals, including humans. Another reason is that life can be studied on various levels in a hierarchy that ranges from the organic-macromolecular level to genes, cells, tissues, organs, and entire organisms. Furthermore, organisms interact in, and can be organized into, families, communities, societies, species, populations, biomes or biota, and perhaps even the global systems (as in the controversial Gaia hypothesis, which postulates that the earth itself is a living organism). To a large extent, biological subdisciplines are organized around each of these levels of activity or organization. Thus, for example, cellular biology, or cytology (coming from the Greek word cyto for cell), deals specifically with the study of cells, while ecology (coming from the Greek word oikos for habitat) deals with interactions between populations, species, communities, and biomes and the processes that sustain them. Since biology deals immediately with living organisms and processes, it has a large applied component. It touches on medical and health-related areas, pharmacy, agriculture, forestry, and biological oceanography. In contemporary society, the promises and problems associated with applications of biology are staggering. They range from stem-cell research, the development and use of genetically modified organisms, and the use of biological tools as identity markers (as in DNA "fingerprinting") to the possibility of designer babies and human cloning. Whereas the physical sciences and their applications dominated science for much of the history of science, the biological sciences now dominate both popular and scientific discussions, especially after the discovery of the structure of DNA in 1953. Viewing the revolution precipitated by the applications of biology to society at the closing of the twentieth century, many commentators anticipate that the new century will be the century of biology.