Ecology

ECOLOGY (from the Greek oikos-house and logos-science), according to the definition proposed by this term's originator E. Haeckel (E. Haeckel, 1869), is the science that studies 'the relations of animals to their organic and inorganic environment, in particular its friendly and hostile relations to those animals and plants with which it comes into contact'. This formulation of the content of Ecology reflects the characteristic features of post-Darwinian development of biological disciplines, when the view of the organism against the background of the environment was established, under the influence of which the organism¹ exists in conditions of the struggle for existence and natural selection. Generalizing the Darwinian direction of study of living forms, Haeckel's definition had in view the adaptive features of organisms. Nevertheless, subsequent authors define the content and tasks of Ecology in very different ways.-Main ecological schools. Many authors adhere to the physiological direction of Ecology e.g. Semper, 1881; Shelford, 1915; Pearce, 1926; D. P. Kashkarov, 1934, and many others), trying to consider Ecology as a branch of physiology, dealing with the study of reactions of the organism as a species, as a whole, in contrast to only physiology in the narrow sense, which is supposedly the physiology of organs. This completely erroneous view deprives Ecology of the specificity of its subject matter and makes it indistinguishable from the mechanics of development (see) and other disciplines that study the effect of environmental factors on the developing or adult organism. Other authors, especially Shelford (Shelford, 1929), Elton (Elton, 1927) and others, want to see in Ecology a science of communities or consider it as a science of the reactions of organisms and their aggregate to environmental influences or as a science of the relations of organisms to the environment (for example McDougall, 1927; Frederiks, 1932, and others). All these definitions of course include the subject matter of Ecology, but at the same time cover problems that other disciplines engaged in the study of 'organism and environment' e.g. physiology, taxonomy, 'biogeography, biocoenology, hydrobiology, etc.) are also interested in, and therefore do not indicate the specificity of Ecology as a science. Such specificity of Ecology is the study of those features of the morpho-physiological (including behavior) organization of living forms that determine their existence in a given environment or in other words correspond to it, i.e. are adapted to it. Ultimately, Ecology is the science of adaptations of organisms to biotic (i.e. created by organisms) and abiotic (physico-chemical) environmental conditions. To avoid misunderstandings, the concept of adaptation should be precisely defined. By the latter should be understood the correspondence in time and space of the morpho-physiological organization of living forms to environmental conditions. One or another type of living being is characterized by a certain area of distribution (range), which however is not continuously populated, but only in certain areas (biotopes) suitable for the life of this given species. Every organism lives in a given life situation because its morpho-physiological organization relatively corresponds, for example, to temperature conditions, humidity, rhythm of seasonal fluctuations, rhythm and amplitude of salinity fluctuations, oxygen regime, pH and other conditions of existence, features of edaphic (soil) factors, conditions created by other organisms, etc. and generally to quite specific, and not any 'limit' of the life situation. Consequently, the study (including laboratory) of the forms of effect of the listed and other environmental factors (or their qualitative aggregate) on the organism is undoubtedly one of the tasks of Ecology, provided that these studies aim at a causal explanation of the existence of these organisms in this environment, i.e. are in fact studies of the adaptability of these organisms to the corresponding conditions. It should be noted that the adaptations of organisms are far from being studied with the desired depth. A synthetic representation of the complex of adaptations of a given form in their qualitative unity, their mutual connection, their mutual conditioning has not yet been achieved.-The definition of Ecology as the science of adaptations is not universally accepted and is disputed, for example, by D. N. Kashkarov (1934), Academician B. A. Keller (1934) and other authors, who however have not brought forward any convincing refutations of the mentioned definition. On the other hand, the understanding of Ecology as the science of adaptations has many defenders (Haeckel, 1869, 1906; S. Detto, 1904; Dahl. 1923; Tschulok, 1910; Thienemann, 1927; in our country M. L. Levin and others). The system of Ecology has not yet been developed. The division proposed by Schroter and Kirchner (Schroter, Kirchner. 1896) into autecology, studying the Ecology of individuals and separate systematic units (species, genus, order, class, etc.), and synecology, studying the Ecology of biocoenoses, is widely spread. On the other hand, another division can be proposed, namely into general Ecology and special Ecology. General Ecology has as its task the study of the general regularities and concepts relating to this science. Special Ecology studies the Ecology of separate systematic groups. The main theoretical tasks of Ecology can be reduced to the following problems. General Ecology deals with: 1) defining Ecology as a science; 2) investigating the phenomena of adaptation as a problem of important methodological significance (relativity of adaptation, factual investigation of this relativity, scope and content of the concept of adaptation, etc.); 3) classification of adaptations and ecological types of organization; 4) studying the history of adaptations in phylogenetic series of forms and in the present; 5) causal investigation of the origin of individual adaptations and investigation of the origin of ecological types (life forms); 6) general analysis of ecological methods of mastering living forms. Special Ecology investigates these questions in application to separate systematic groups or separate biocoenoses. In accordance with this, one can speak of the Ecology of plants, the Ecology of animals, the Ecology of protozoa, coelenterates, echinoderms, vertebrates, birds, mammals, etc. or the Ecology of various biocoenoses. The relationship of Ecology to evolutionary theory is evident from what has been said above. By studying the history of adaptations or the reasons for the survival of one or another ecological types, Ecology thereby provides valuable material for studying the problems of speciation, as well as the problems of the evolutionary process as a whole, since the evolutionary process always has an adaptive character. The practical significance of Ecology is enormous. By studying the ecological moments of existence of given forms in given conditions, we thereby establish to what exact conditions these forms are adapted, and consequently we are in a position to foresee, and ultimately to control living organisms. Ecology in combination with genetics, selection and physiology is a powerful tool in the work of changing nature in the interests of socialist society. The importance of Ecology of agricultural pests-rodents, insects, roundworms, mollusks is very important.-The significance of Ecology in medicine is no less great. Thus, the study of the Ecology of various vectors of infectious diseases e.g. Ecology of malarial mosquitoes, ground squirrels, etc.) or the Ecology of free-living adult or larval forms of various parasitic worms and their intermediate and final hosts is of enormous importance. At present, Ecology is particularly strongly developing in the USA, to a lesser extent in England and other countries. In the USSR Ecology is rapidly catching up and in many ways is ahead of the ecology of capitalist countries. Ecological laboratories in the USSR are concentrated mainly in Moscow and Leningrad. Lit.:Questions of Ecology and Biocoenology, collection edited by D. Kashkarov and M. Levin, M.-L., 1934; Genderson L., Among Life, M.-L., 1924; Journal of Ecology and Biocoenology, M., 1930 (only vol. I was published); Kashkarov D., Environment and Community, M., 1933 (bibliography); he same, Content and Paths of Soviet Ecology, Sov. Botanika, 1934, No. 3; Frederiks K., Ecological Foundations of Applied Zoology and Entomology, L.-L., 1932; Elton Ch., Animal Ecology, M.-L., 1934 (bibliography); Adams C, Guide to the study of animal ecology, N. Y., 1913; Dahl F., Grundlagen einer Oekologischen Tiergeographie, Jena, 1923; Haeckel E., Generelle Morphologie d. Organismen, B., 1866; he same, Prinzipien der generellen Morphologie d. Organismen, B., 1906; Hesse R., Die Okologie der Tiere, Naturwissenschaften, B. XV, 1927; Mac Dougall W., Plant ecology, L., 1927; Weaver, Animal ecology, N. Y., 1926; Shelford V., Principal problems of ecology as illustrated by animals, Journ. of ecol., v. III,1915; he same, Laboratory and field ecology, Baltimore, 1929. Periodical publication.-Journal of ecology, Cambridge, since 1913.