Environment

Environment, a convenient collective term employed in biology for the conditions of existence, or inanimate and animate surroundings, among which an organism lives. The opinion is gaining ground that this environment has had a leading influence in producing adaptive modifications of organisms by its direct actions. Geoffrey St. Hilaire in 1795 and Lamarck (q.v.) in 1801 attributed much to what the former termed "le monele ambiant," as did Robert Chambers in the Vestiges of Creation (1844). Mr. Herbert Spencer has always done so; but Darwin at first laid far more stress on inherent variability. Drs. August Weismann and Karl Semper have since insisted on the paramount influence of the environment on animals, as has the Rev. George Henslow in the case of plants.

Food, light, temperature, movement and salinity of water, dryness or moisture of the air, among inorganic influences, and the action of parasites (q.v.) or of similar competing organisms, among those that are organic, contribute to this, environment. The absence of colour in cave animals and its uniformity in other cases, as in the "sabelline" or sandy hue of desert animals, have been attributed to the direct action of the environment. "Melanic," or dark, varieties are said to be connected with increased atmospheric moisture; even the origin of flowers is explained by the response of the plant to mechanical irritation by insects.