BIONOMICS, in biology, the study of the habits and modes of life of animals or plants and their relations to each other, to all living beings and to the world around them. It cor responds to (ecology)) and to °biology') as used by German naturalists. Wasmann defines bi ology in the restricted sense of bionomics as — "The science of the external conditions of existence, which pertain to organisms ma individuals and at the same time regulate their relations to other organisms and to the inorganic environment." It therefore, he says, embraces in its restricted sense — "First. a knowledge of the mode of life of animals and plants. their nourishment. dwelling, mode of propagation, the care of offspring and their development, in so far as these present external manifestations; hence also. second. a knowledge of the life-relations that obtain between indi viduals of the same and different species (including all the phenomena of parasitism, symbiosis, etc.). and hence also, third. a knowledge of the conditions of existence which are essential to the life and maintenance of animals and plants." By conditions of existence are meant the action on plants and animals of climate, soil, light, gravity, heat, the dryness or moisture in the air and soil; the nature of the water, whether salt, fresh or brackish; currents of air and of water; elevation above the sea, also any other physi cal and biological agents in causing variation in or modification of organisms. As Wheeler
states: "Whenever we undertake the detailed or exhaustive study of an ethological problem, we are led imperceptibly into the details of physiology, morphology, embryology. taxonomy, or chorology. according to the particular aspect of the subject under consideration." Many of these subjects, falling under the head of bionomics, are treated under the head of evolution (q.v.), as the struggle for exist ence, mimicry, etc. Another department of bio nomics is geographical distribution and distri bution in time, together with migration, hered ity, hibernation and seasonal dimorphism. The word ubionomics)) seems preferable to (cethol ogy,3) which has been used as the name of the science of ethics; it is also the more compre hensive tertn. Consult papers by Bessey (Sci ence, XV, p. 593); Bather (Science, XV, p. 748) ; Wheeler (Science, XV, 20 June 1902). The writings of Reaumur, Audubon Huber, Lubbock, Plateau, Fabre, Ford, Wasmann, Riley, Wheeler and others deal especially with the habits and economy .or bionomics of insects (bees and ants) and birds. Consult also Waether, (Einleitung in die Geologie,) parts ii; (Bionomie der Meeresthiere) and (Lebens weise der Meeresthiere.) See ECOLOGY.