bioengineering Application of engineering principles and equipment to biology and medicine. It includes the development and fabrication of life-support systems for underwater and space exploration, devices for medical treatment (see dialysis, prosthesis), and instruments for monitoring biological processes. Development has been particularly rapid in the area of artificial organs, which culminated in the implantation of an artificial heart into a human being in 1982. Bioengineers also develop equipment that enables humans to maintain body functions in hostile environments, such as the space suits worn by astronauts during extravehicular maneu¬ vers.
biofeedback Information supplied instantaneously about an individu¬ al’s own physiological processes. Data concerning cardiovascular activ¬ ity (blood pressure and heart rate), temperature, brain waves, or muscle tension is monitored electronically and returned or “fed back” to the indi¬ vidual through a gauge on a meter, a light, or a sound. The goal is for the patient to use that biological data to learn to voluntarily control the body’s reactions to stressful external events. A type of behaviour therapy, biofeed¬ back training is sometimes used in combination with psychotherapy to help patients understand and change their habitual reactions to stress. Com¬ plaints treated through biofeedback include migraine headaches, gas¬ trointestinal problems, high blood pressure, and epileptic seizures.
biography Form of nonfictional literature whose subject is the life of an individual. The earliest biographical writings probably were funeral speeches and inscriptions. The origins of modern biography lie with Plu¬ tarch’s moralizing lives of prominent Greeks and Romans and Suetonius’s gossipy lives of the Caesars. Few biographies of common individuals were written until the 16th century. The major developments of English biography came in the 18th century, with such works as James Boswell’s Life of Johnson. In modern times impatience with Victorian reticence and the development of psychoanalysis have sometimes led to a more pen¬ etrating and comprehensive understanding of biographical subjects. See also AUTOBIOGRAPHY.
Bioko \be-'o-ko\ formerly Fernando Po \fer-'nan-do-'po\ Island (pop., 1987 est.: 67,920), Bight of Biafra, West Africa. It lies 100 mi (160 km) northwest of continental Equatorial Guinea, of which it is a part. Bioko became the official name in 1979. Volcanic in origin, with an area of 779 sq mi (2,018 sq km), it rises sharply from the sea; its highest point is Santa Isabel Peak, at 9,869 ft (3,008 m). Malabo, the country’s capital, is located on Bioko. The island was visited by the Portuguese explorer Fernao Po, probably in 1472. Though the island was claimed by Spain after 1778, the first attempt at firm Spanish control came only in 1858. The original inhabitants, the Bubi, are descendants of Bantu-speaking migrants from the mainland. Many Fang have flocked to the island from the continent.
biological rhythm Periodic biological fluctuation in an organism cor¬ responding to and in response to periodic environmental change, such as day and night or high and low tide. The internal mechanism that main¬ tains this rhythm even without the apparent environmental stimulus is a “biological clock.” When the rhythm is interrupted, the clock’s adjust¬ ment is delayed, accounting for such phenomena as jet lag when travel¬ ing across time zones. Rhythms may have 24-hour (circadian rhythm), monthly, or annual cycles. See also photoperiodism.
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biological warfare ► biotite I 221
biological warfare or germ warfare Military use of disease- producing or poisonous agents, and the means for defending against such agents. Biological warfare agents include many bacteria, such as those which cause anthrax, brucellosis, and typhus; viruses that cause diseases such as equine encephalitis; fungi such as rice blast, cereal rust, wheat smut, and potato blight; and toxins such as botulinum and ricin that are extracted from living organisms. Biological warfare dates from ancient times when warring groups would try to poison enemy soldiers with rotting or dis¬ eased corpses, infect cattle and horses, or spread contagion through civil¬ ian populations. Following the horrors of World War I, a 1925 Geneva Protocol prohibited the use of biological agents in warfare; however, this did not prevent Japan from using them in China during World War II. During the Cold War the Soviet Union as well as the U.S. and its allies built huge stockpiles of biological agents. Both sides signed the 1972 Biological Weapons Convention, which prohibits the production, stock¬ piling, or development of biological weapons and requires the destruction of existing stockpiles, but the Soviets conducted a clandestine program until the 1990s. Biological weapons programs can be concealed easily, and the 1972 convention contains no provisions for inspection and report¬ ing. As a result, many states have been suspected of developing biologi¬ cal warfare agents, and some modern armed forces have prepared defensive measures. These include battlefield sensors, protective garments and masks, sterilizing agents, and vaccines.
biology Study of living things and their vital processes. An extremely broad subject, biology is divided into branches. The current approach is based on the levels of biological organization involved (e.g., molecules, cells, individuals, populations) and on the specific topic under investiga¬ tion (e.g., structure and function, growth and development). According to this scheme, biology’s main subdivisions include morphology, physiology, taxonomy, embryology, genetics, and ecology, each of which can be further subdivided. Alternatively, biology can be divided into fields especially concerned with one type of living thing; for example, botany (plants), zoology (animals), ornithology (birds), entomology (insects), mycology (fungi), microbiology (microorganisms), and bacteriology (bacteria). See also biochemistry; molecular biology.
biology, philosophy of Philosophical investigation of the concepts, problems, and methods of the biological sciences. Many of the topics considered in contemporary philosophy of biology have arisen from reflection on aspects of the theory of evolution. They include the question of whether evolution is ultimately falsifiable, a conventional requirement of all scientific theories; whether the thesis of natural selection has empiri¬ cal content or is merely a tautology; whether selection operates at the level of the individual, the species, or the gene; and whether selection is guided by certain constraints controlling development at the molecular level. Other more general issues concern the possible reduction of biological theories to theories of the physical sciences, the role of teleological lan¬ guage in biology (see teleology), and the nature of species as a biological category. See also creationism; sociobiology.
bioluminescence \ l bI-o- l lii-m3- , ne-s 3 ns\ Emission of light by an organism or biochemical system (e.g., the glow of bacteria on decaying meat or fish, the phosphorescence of protozoans in tropical seas, the flickering signals of fireflies). It occurs in a wide range of protists and animals, including bacteria and fungi, insects, marine invertebrates, and fish. It is not known to exist naturally in true plants or in amphibians, reptiles, birds, or mammals. It results from a chemical reaction that pro¬ duces radiant energy very efficiently, giving off very little heat. The essen¬ tial light-emitting components are usually the organic molecule luciferin and the enzyme luciferase, which are specific for different organisms. In higher organisms, light production is used to frighten predators and to help members of a species recognize each other. Its functional role in lower organisms such as bacteria, dinoflagellates, and fungi is uncertain. Luminous species are widely scattered taxonomically, with no clear-cut pattern, though most are marine.