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What are biomes?

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Key points

  • Biomes are large-scale . Examples of biomes include tropical rainforests, hot deserts, deciduous forests, boreal (taiga) forests and tundra.
  • The location of global biomes is determined by several factors, including latitude, altitude, and ocean currents.
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What are biomes?

The surface of the Earth can be divided according to biomes.

Global biomes
Figure caption,
A map showing the distribution of the global ecosystems or biomes
  • Tropical rainforest
    Tropical rainforests are found between the Tropics of and , 23.5掳 north and south of the . These dense forests grow in hot, wet conditions and a wide range of animals, such as monkeys, jaguars and parrots, live here.

  • Boreal (taiga) forests
    Cold environments, where often falls as snow. Evergreen coniferous trees, often with needles and cones, grow here. Moose, bears, lynx and wolves live in these forests.

  • Hot desert
    Dry areas with vegetation, commonly found along the Tropics of Cancer and Capricorn. plants, such as cacti, and many types of reptiles and insects are found here.

  • Tundra
    Cold, dry climates found almost entirely in the far north of the planet. Permafrost prevents trees from growing, but low-lying plants such as mosses thrive. Reindeer and Arctic foxes live here.

  • Deciduous forests
    Temperate climates, which means that they are not too hot or too cold. Trees such as oak and elm that lose their leaves during cooler months grow here. Animals such as owls, red deer and badgers live in these forests.

An elk emerging from a boreal forest next to a lake
Image caption,
Boreal (taiga) forests have evergreen trees, often with needles and cones

How different species have adapted to live in the Arctic tundra

Question

Which biome do reindeer live in?

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Why do global biomes vary?

The characteristics of global biomes are determined by several factors.

Biomes closer to the are hotter as the sun鈥檚 radiation is more concentrated here due to the curvature of the Earth. Biomes closer to the poles are therefore colder. The of air evens out this difference in temperature. The movement of air in part of this air circulation, known as the Hadley Cell, is responsible for the moist air that rises at the equator and the dry air that falls over the Earth鈥檚 deserts.

Global atmospheric circulation
Figure caption,
Global atmospheric circulation is responsible for the dry air that falls over the Earth鈥檚 deserts

Higher land is cooler and wetter. There is a decrease in air temperature of around 0.6 to 0.7 掳C for every 100 m gained in height. Cold mountain or alpine biomes are found at high altitude, even along the equator.

The sea retains heat during colder months, but remains cool during warmer months. Places closer to the sea have milder and often wetter biomes than those inland. This can be seen with the more moderate temperatures experienced along the coastline of south-western Europe.

Ocean currents

Warm ocean currents bring milder temperatures and higher . Cold ocean currents bring cooler temperatures and lower precipitation. A cold ocean current flowing along the south-west coast of Africa created the Namib desert.

Question

Which biome is found at high altitudes?

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What is climate?

The global atmospheric circulation system determines many climates.

Image gallerySkip image gallerySlide 1 of 4, The movement of air across the planet occurs in a specific pattern. The whole system is driven by the Equator, which is the hottest part of the Earth. Air moves in six large cells: three in the Northern Hemisphere and three in the Southern Hemisphere. The cells have names: the Hadley cells, the Ferrel cells and the Polar cells. , Global atmospheric circulation The movement of air across the planet occurs in a specific pattern. The whole system is driven by the Equator, which is the hottest part of the Earth. Air moves in six large cells: three in the Northern Hemisphere and three in the Southern Hemisphere. The cells have names: the Hadley cells, the Ferrel cells and the Polar cells.

Factors that determine the climate of a country and the five main climate zones of the world

Question

What type of climate is found where air rises?

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Test your knowledge

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Play the Planet Planners game! game

Make decisions for the planet in this KS3 geography game.

Play the Planet Planners game!
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