Презентация на тему Natural zones of the Earth

rainforest;
savanna.

is hindered by low temperatures and short growing seasons.

The term tundra comes from Kildin Sami language, which means "uplands, treeless mountain tract". There are two types of tundra: Arctic tundra (which also occurs in Antarctica) and alpine tundra. In tundra, the vegetation is composed of dwarf shrubs, sedges and grasses, mosses, and lichens. Scattered trees grow in some tundra.

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Covering most of inland Alaska, Canada, Sweden, Finland, inland

Norway, the Scottish Highlands and Russia (especially Siberia), as well as parts of the extreme northern continental United States (Northern Minnesota, Michigan's Upper Peninsula, Upstate New York, Vermont, New Hampshire, and Maine), northern Kazakhstan and Japan (Hokkaido) the taiga is the world's largest terrestrial biome.

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receives almost no precipitation. Deserts are defined as areas

with an average annual precipitation of less than 250 millimetres (10 in) per year, or as areas where more water is lost by evapotranspiration than falls as precipitation. In the Thornthwaite climate classification system, deserts would be classified as arid megathermal climates.

The typical structure of these forests include four layers.

The upper most layer is the canopy which is composed of tall mature trees. Below the canopy is the three-layered, shade tolerant understory. The top layer of the understory is the sub-canopy which is composed of smaller mature trees, saplings, and suppressed juveniles canopy layer trees awaiting an opening in the canopy.

the eastern and western United States, Canada, central Mexico,

South America, Europe, China, Japan, North Korea, South Korea and parts of Russia. A temperate deciduous forest consists of trees that lose their leaves every year. Some of these trees include oak, maple, beech, and elm.

around the equator. They are common in Asia, Australia,

Africa, South America, Central America, Mexico and on many of the Pacific Islands. Within the World Wildlife Fund's biome classification, tropical rainforests are considered a type of tropical wet forest (or tropical moist broadleaf forest) and may also be referred to as lowland equatorial evergreen rainforest.

characterized by the trees being sufficiently small or widely

spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses.