B I O M E

Biome, is a plant and animal community that covers a large geographical area. The boundaries of different biomes on land are determined mainly by climate. Aquatic biomes are not easily defined. Important land biomes include (1) tundra, (2) coniferous forests, (3) deciduous forests, (4) grasslands, (5) savannas, (6) deserts, (7) chaparral, (8) tropical rain forests, and (9) tropical seasonal forests. Most ecologists distinguish between the temperate coniferous forest biome and the northern coniferous forest biome, also known as the boreal forest biome or the taiga biome.

Each biome is characterized by distinctive kinds of plants and animals and by a specific climate. For example, northern coniferous forests have a harsh climate with long, cold winters and short summers. The major plants in this biome are cone-bearing evergreen trees, such as spruces, firs, and pines. Moose, caribou, and other deer are the dominant plant-eating animals in northern coniferous forests. Some ecologists name biomes to show the importance of both animals and plants. The northern coniferous forest is sometimes called the spruce-moose biome, and the temperate deciduous forest also may be referred to as the oak-deer-maple biome.

The same biome includes similar communities that occur in different parts of the world. For example, the grassland biome includes the steppes of Asia, the prairies and plains of North America, the veld of southern Africa, and the pampas of South America. The species of grasses may differ in each of these regions. But these areas all share the same form of vegetation.

The ways in which plants and animals in a biome interact with each other determine their niche in the biome. A niche is the ecological "job and address" of a plant or animal in nature. The "job" refers to the function of the plant or animal, and the "address" refers to its habitat in the biome. For example, grazing is a major function of many animals in the grassland biome. Bison (American buffaloes) once functioned as the dominant grazers on North American grasslands. Today, on African grasslands, zebras and several kinds of gazelles and antelopes together fill the grazing niche. Plants or animals that fill the same niche in different places, such as bison in North America and gazelles in Africa, are called ecological equivalents.