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Biome, in ecology, is the term applied to the major biological communities which make up the biosphere. The concept is geographical and largely a function of human attempts to classify their environment into broad groups such as rainforest, though such categories are complex collections of smaller communities which interact at a number of levels. Communities respond to similar environmental conditions by parallel development in terms of the species types of which they consist: this gives rise to biome types such as mangrove swamp and coniferous forest.
Biomes of the same type are often seen on several different continents; for example, shrubland is a biome type found in different forms around the world. The species which make up geographically separate biomes of the same type are often different, but have evolved communities of similar structure as a result of parallel, independent responses to similar environmental conditions. Climate is the most important environmental factor in this convergent evolution and, as a result, given biome types are restricted to certain global areas: tropical rainforest, for example, is a biome type which is restricted to equatorial zones, while deciduous forest is found in more temperate areas to the north and south of the tropics. However, a number of other, more local factors such as soil type and altitude are also of importance in determining biome type. Furthermore, the biome and the physical environment interact and modify one another; the quality of soil is dependent upon the vegetation as well as on geology and climate, and humidity and rainfall are greatly affected by biome type. RB
See also biodiversity; ecosystem. |
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