BIOLOGY

study of living things and their vital processes. The field deals with all the physicochemical aspects of life. As a result of the modern tendency to unify scientific knowledge and investigation, however, there has been an overlapping of the field of biology with other scientific disciplines. Modern principles of other scienceschemistry and physics, for exampleare integrated with those of biology in such areas as biochemistry and biophysics. Because biology is such a broad subject, it is subdivided into separate branches for convenience of study. Despite apparent differences, all the subdivisions are interrelated by basic principles. Thus, though it was once the custom to separate the study of plants (botany) from that of animals (zoology), and the study of the structure of organisms (morphology) from that of function (physiology), the current practice is to investigate those biological phenomena that all living things have in common. Biology is often approached today on the basis of levels that deal with fundamental units of life. At the level of molecular biology, for example, life is regarded as a manifestation of chemical and energy transformations that occur among the many chemical constituents that comprise an organism. As a result of the development of more powerful and precise laboratory instruments and techniques, it is now possible to understand and define more exactly not only the invisible ultimate physiochemical organization (ultrastructure) of the molecules in living matter but also how living matter reproduces at the molecular level. Cell biology, the study of the fundamental unit of structure and function in a living organism, may be said to have begun in the 17th century, with the invention of the compound microscope. Before that, the individual organism was studied as a whole (organismic biology), an area of research still regarded as an important level of biological organization. Population biology deals with groups or populations of organisms that inhabit a given area or region. Included at this level are studies of the roles that specific kinds of plants and animals play in the complex and self-perpetuating interrelationships that exist between the living and nonliving world, as well as studies of the built-in controls that maintain these relationships naturally. These broadly based levels may be further subdivided into such specializations as morphology, taxonomy, biophysics, biochemistry, genetics, eugenics, and ecology. In another way of classification, a field of biology may be especially concerned with the investigation of one kind of living thinge.g., botany, the study of plants; zoology, the study of animals; ornithology, the study of birds; ichthyology, the study of fishes; mycology, the study of fungi; microbiology, the study of microorganisms; protozoology, the study of one-celled animals; herpetology, the study of amphibians and reptiles; entomology, the study of insects; and physical anthropology, the study of man. the study of living things and their vital processes. The field deals with all of the physicochemical aspects of life. Because biology is such a broad subject, it has been subdivided into separate branches for convenience of study. Despite apparent differences, all these subdivisions are interrelated by the basic principles that underlie all biological manifestations. The current approach to the study of living things is based on the levels of biological organization involvedwhether molecules, cells, individuals, or populationsand on the specific subject matter under investigatione.g., structure and function, types and classification, and growth and development. The study of the individual organism as a whole (organismic biology) dominated biology until the invention of the compound microscope (17th century) and the consequent rise of cell biology. Because each of the aforementioned levels is still too broad to be easily grasped by any one individual, a number of subdivisions have arisen over time. These include morphology, the study of the shape and structure of plants and animals; physiology, the study of the functions of cells, tissues, organs, and organ systems in living things; taxonomy, which attempts to classify living things into groups according to observed natural or hypothetical relationships; embryology, which is concerned with the formation and development of the embryo in plants and animals; genetics, which is the study of inheritance and variation in organisms and the mechanisms by which these processes operate; and ecology, the study of organisms and their interactions with other organisms and their environment. Each of these subdivisions, in turn, can be further subdivided: morphology, for example, is divided into anatomy, which is the study of structures that can be observed with the naked eye; histology, the study of microscopic structure; and cytology, the study of the particular minutiae of cellular structure. There has also been an overlapping of the field of biology with other scientific disciplines; for instance, the modern principles of chemistry and physics are integrated with those of biology in biochemistry and biophysics, respectively. Molecular biology, which studies the chemical structures and processes of biological phenomena at the molecular level, draws on several disciplines and has become one of the most important biological sciences. In another approach to classification, a field of biology may be especially concerned with the investigation of one type of living thinge.g., botany, the study of plants; zoology, the study of animals; ornithology, the study of birds; ichthyology, the study of fishes; herpetology, the study of amphibians and reptiles; entomology, the study of insects; mycology, the study of fungi; microbiology, the study of microorganisms; protozoology, the study of protozoa; and bacteriology, the study of bacteria. Additional reading Basic concepts of biology Two well-written and lavishly illustrated general beginning undergraduate biology textbooks are William K. Purves, Gordon H. Orians, and H. Craig Heller, Life: The Science of Biology, 4th ed. (1994); and Neil A. Campbell, Biology (1993). Stephen Jay Gould, The Panda's Thumb: More Reflections in Natural History (1980, reissued 1992), is one of his many interesting collections of essays on natural history. R.C. Lewontin, Biology as Ideology: The Doctrine of DNA (1991), written by one of the leading population geneticists in the United States, discusses the political and societal impact of some recent advances in genetics, with a decided left-wing bias. Ashley Montagu, Science and Creationism (1984), is an important contribution to the debate. Jacques Monod, Chance and Necessity: An Essay on the Natural Philosophy of Modern Biology (1971; originally published in French, 1970); Franois Jacob, The Possible and the Actual (1982, reissued 1994); and Andr Lwoff, Biological Order (1962), combine the authors' perspectives of living systems, with special reference to their genetic foundations, and their quasi-philosophical thoughts about the nature of living organisms. Lewis Thomas, The Lives of a Cell: Notes of a Biology Watcher (1974, reissued 1986), contains many noteworthy biological insights. Edward D. Garber (ed.), Genetic Perspectives in Biology and Medicine (1985), details some of the ways in which knowledge of the molecular genetics of cells and the new technologies thereby inspired have made major contributions to medicine. The Editors of the Encyclopdia Britannica The history of biology Publications concerned with the history and philosophy of biology include Charles Singer, A History of Biology, rev. ed. (1950), a highly readable classic that surveys the historical development of biological problems; Mordecai L. Gabriel and Seymour Fogel (eds.), Great Experiments in Biology (1955), a presentation of scientific writings from Robert Hooke to the 20th century; Bentley Glass, Progress or Catastrophe: The Nature of Biological Science and Its Impact on Human Society (1985), a philosophical text for the intellectual reader; Alexander Rosenberg, The Structure of Biological Science (1985), an advanced, complex philosophical discourse on the discipline of biology and its intellectual status among the more physical sciences such as physics and chemistry; Arthur M. Silverstein, A History of Immunology (1989), a scholarly history of immunological concepts and topics up to the early 1960s; and Anthony Serafini, The Epic History of Biology (1993). William Coleman, Biology in the Nineteenth Century (1971, reprinted 1987), gives special attention to morphology and physiology. Garland E. Allen, Life Science in the Twentieth Century (1975), emphasizes the growth of molecular biology. Peter J. Bowler, Evolution: The History of an Idea, rev. ed. (1989), surveys evolutionary ideas through Darwin. Edna R. Green The Editors of the Encyclopdia Britannica The history of biology There are moments in the history of all sciences when remarkable progress is made in relatively short periods of time. Such leaps in knowledge result in great part from two factors: one is the presence of a creative minda mind sufficiently perceptive and original to discard hitherto accepted ideas and formulate new hypotheses; the second is the technological ability to test the hypotheses by appropriate experiments. The most original and inquiring mind is severely limited without the proper tools to conduct an investigation; conversely, the most sophisticated technological equipment cannot of itself yield insights into any scientific process. An example of the relationship between these two factors was the discovery of the cell. For hundreds of years there had been speculation concerning the basic structure of both plants and animals. Not until optical instruments were sufficiently developed to reveal cells, however, was it possible to formulate a general hypothesis, the cell theory, that satisfactorily explained how plants and animals are organized. Similarly, the significance of Gregor Mendel's studies on the mode of inheritance in the garden pea remained neglected for many years, until technological advances made possible the discovery of the chromosomes and the part they play in cell division and heredity. Moreover, as a result of the relatively recent development of extremely sophisticated instruments, such as the electron microscope and the ultracentrifuge, biology has moved from being a largely descriptive scienceone concerned with entire cells and organismsto a discipline that increasingly emphasizes the subcellular and molecular aspects of organisms and attempts to equate structure with function at all levels of biological organization. The early heritage Although it is not known when the study of biology originated, early man must have had some knowledge of the animals and plants around him. His very survival depended upon the accurate recognition of nonpoisonous food plants and upon an understanding of the habits of dangerous predators. Archaeological records indicate that even before the development of civilization, man had domesticated virtually all the amenable animals available to him and had developed an agricultural system sufficiently stable and efficient to satisfy the needs of large numbers of people living together in communities. It is clear, therefore, that much of the history of biology predates the time at which man began to write and to keep records.