Bioorientation

the capacity of organisms to determine their own position in space, to choose the optimal location with respect to the forces acting upon them (environmental factors), and to determine a biologically favorable direction for movement.

Bioorientation is one of the basic conditions for the adaptation of organisms to the environment. This adaptation can proceed along one of three paths: a change in the state of an organism in accordance with changing conditions (morphophysiological adaptations); a change of location; a change in the surroundings by the formation of groups (for example, herds) or by the construction of shelters (burrows, nests, and so on). Bioorientation is a function of sensitivity to and perception of physical, chemical, and biological external effects. In higher invertebrates (arthropods and mollusks) and in vertebrate animals, external effects (signals) are perceived by special sensory organs, and their bioorientation reactions take on the character of complex instincts which provide the basis for bionavigation. The choice of direction during locomotion is based on chemical, mechanical (tactile), acoustic, electrical, or optical stimuli (signals) and their location—that is, the determination of their position in relation to the animal. The function of most locating mechanisms is ensured by pairs of sensory organs (for instance, sight, hearing, and balance) which permit the signals to be compared; strength, frequency, and other parameters of the signals entering the right and left sensory organs are gauged to determine the direction of their source.