Life Zone

life zone [′līf ‚zōn]

(ecology)

A portion of the earth's land area having a generally uniform climate and soil, and a biota showing a high degree of uniformity in species composition and adaptation.

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Life Zone 

one of the large subdivisions of the biosphere; a spatially expressed complex of abiotic, mainly climatic, factors and groups of plants and animals that have adapted to them. The concept of the life zone was introduced by the American scientist C. H. Merriam in 1890.

On land, a distinction is made between horizontal life zones (tundra, taiga, steppe, and so on) and vertical life zones. The latter are found in mountain areas (alpine meadows, mountain forests, and so on). Life zones in the oceans are longitudinal (two polar zones with constant low temperature and floating ice, two temperate zones with sharp seasonal temperature fluctuations, and one equatorial zone with constant high temperature) and vertical (littoral, sublittoral, deep-sea, abyssal, and so on). The fact that life zones are insufficiently distinguished from topographical zones has led to a failure to use the term “life zone.”