Environmental Physiology

a branch of physiology that studies the dependence of human and animal functions on conditions of life and activity in different physicogeographical zones, during different times of the year and day, and at different phases of the moon and tidal rhythms. Environmental physiology, which reveals the physiological bases of adaptations to natural factors, is closely tied in with ecology, chronobiology, the physiology of aging and evolution, the physiology of farm animals, and ethology; when the subject of study is man, it is also closely related to climatophysiology and the physiology of work and sports. All levels of physiological integration are studied: supraorganismic (populational), organismic, organic and systemic, and cellular and subcellular (molecular). In human environmental physiology, clinical, chemical and electrophysiological laboratory methods, such as radiotelemetry, are used.

The development of adaptations is studied by isolating an organism from individual environmental factors (controlled cultivation and rearing) and by comparing the parameters of physiological reactions in species that are taxonomically similar but that have different ecological specialization, such as arctic, tropical, desert, terrestrial, and semiaquatic organisms with different levels of muscle activity. In research on sensory systems, signalization, echolocation and ranging (bats, birds, fish), and chemical links (pheromones) between organisms, environmental physiology depends upon biophysical and biochemical data.

Environmental physiology enables man to forecast the mass multiplication of pests (rodents, insects) and acclimatize beneficial animal species; it also makes possible the regionalization of farm animals by breeds and the acclimatization of man to new climatic regions as new areas are developed (high latitudes, mountains, deserts). It studies the physiological characteristics that determine the course of the adaptive reactions in various animals inhabiting particular regions (seeLIFE FORM). At various phylogenetic levels, such general characteristics include mechanisms for the conservation of water in desert animals, osmotic control in desert, semiaquatic, and aquatic organisms, and the energy flow in organisms and their individual systems (high in northern latitudes and low in arid and tropical zones).

In the USSR, research in environmental physiology has been conducted since the 1930’s, including the study of thermoregulation (A. D. Slonim, O. P. Shcherbakova), adaptation to hot and cold climates (A. Iu. Iunusov, I. A. Izrael’), adaptation to mountainous conditions (A. G. Ginetsinskii, N. N. Sirotinin, M. M. Mirrakhimov), adaptation to environments with a variable gaseous composition (E. M. Kreps, Z. I. Barbasheva), and mechanisms of hibernation (N. I. Kalabukhov). The ecological approach was also used in the study of the nervous system (D. A. Biriukov) and the genetics of behavior (D. K. Beliaev, M. E. Lobashev). Beginning in the 1950’s, research in environmental physiology expanded in connection with the development of new territories, such as the arctic, subarctic, deserts, and mountainous regions; bases have been established at mountain, desert, and marine stations, and laboratories have been set up at wildlife sanctuaries. A pressing need is developing to investigate the effects of noise, vibration, and temperature factors on the human body as a whole and on the function of individual organs (V. V. Parin, A. S. Troshin).

Various aspects of environmental physiology have been studied abroad since the 1920’s, including the comparative physiology of respiration and muscle activity (A. Krogh), the effect of decreased air pressure on the respiratory function of the blood (J. Barcroft), adaptation to low temperatures (C. L. Prosser, T. H. Bullock, and P. F. Scholander; USA), the adaptation of animals to desert life (K. Schmidt-Nielsen; USA), and the physiology of human work under extreme arctic and desert conditions (O. G. Edholm; Great Britain). Since the 1970’s, the problems of environmental physiology have become closely linked with those of conservation. (See alsoPHYSIOLOGY.)