Natural Regions of the World
ICSE Class 9 · Geography · Chapter 20
What this chapter covers
- Meaning and basis of natural regions
- Equatorial region
- Tropical grasslands
- Tropical deserts
- Tropical monsoon region
- Mediterranean region
- Temperate grasslands
- Taiga
- Tundra
Key definitions
Natural vegetation is the plant cover that grows in a place on its own, without being planted or tended by people.
Rice is the chief food crop, because it needs high temperatures and plenty of water, and much of the work in the paddy fields is still done by hand and with bullocks.
Key points
- A natural region has broadly the same climate, natural vegetation and animal life throughout; climate is the main basis for dividing the world into natural regions.
- Equatorial region (5°-10° N and S): Amazon and Congo basins and South-East Asia; hot and wet all year, annual range 2 °C-3 °C, daily convectional rain over 200 cm; evergreen rainforest (selvas) of hardwoods; hunting-gathering, shifting cultivation and plantations of rubber, oil palm and cocoa.
- Tropical grasslands (5°-20°): savanna, llanos and campos and northern Australia; hot wet summer and warm dry winter; tall grass with acacia and baobab; Maasai herders, Hausa farmers, ranches and game parks.
- Tropical deserts (15°-30°, western margins): Sahara, Arabian, Thar, Kalahari, Atacama and Australian deserts; under 25 cm of rain and a large diurnal range, caused by descending air, off-shore trade winds and cold currents; xerophytes and oases; nomads, oasis farming, oil and minerals.
- Tropical monsoon (10°-30°, eastern and southern margins): South and South-East Asia and northern Australia; seasonal reversal of winds, three seasons and summer rain; deciduous teak and sal forests; densely populated rice-growing lands with kharif and rabi crops.
- Mediterranean (30°-45°, western margins): the Mediterranean basin, California, central Chile, the Cape and south-western Australia; hot dry summers and mild wet winters brought by the westerlies; evergreen trees with leathery leaves; orchard lands of citrus, olives and grapes, and tourism.
- Temperate grasslands (30°-55°, interiors): Prairies, Steppes, Pampas, Veld and Downs; continental extremes and light summer rain; short grass without trees; mechanised wheat farming, cattle ranching and sheep rearing.
- Taiga (50°-70° N only): Canada, Scandinavia and Siberia; long severe winters, short cool summers and the largest annual range; coniferous softwoods such as pine, fir, spruce and larch; lumbering, paper, fur trapping and mining.
- Tundra (65°-80° N): Arctic coasts of North America, Greenland and Eurasia; coldest climate, warmest month below 10 °C, permafrost; mosses, lichens and dwarf shrubs; Inuit hunters, Sami reindeer herders, oil and mining.
Questions answered
Define a natural region. On what basis are natural regions mainly identified?
A natural region is a large part of the earth's surface with broadly the same climate, natural vegetation and animal life, whose people face similar conditions and adapt in similar ways. Natural regions are identified mainly on the basis of climate, because temperature and rainfall control the vegetation, the animals and human activity.
Why is the annual range of temperature in the Equatorial region only about 2 °C to 3 °C?
The midday sun is nearly overhead at the equator throughout the year, and the length of day and night hardly changes, so every month receives almost the same amount of heat.
Give two reasons why commercial lumbering is difficult in the equatorial rainforest.
Many species grow mixed together, so trees of one useful kind are scattered; and the hardwoods are heavy and difficult to cut and transport through the dense, swampy forest. The hot, humid climate and diseases also discourage workers.
Name the tropical grasslands of Africa, the Orinoco basin and the Brazilian Highlands. State two ways in which the trees of these grasslands are adapted to the dry season.
Savanna, llanos and campos. The baobab and the bottle tree store water in thick trunks, and the acacia has small leaves and an umbrella shape that reduce water loss; many trees also shed their leaves in the dry season and have thick bark against fire.
Explain why hot deserts are found on the western margins of the continents between 15° and 30° latitude.
These latitudes lie under the sub-tropical high-pressure belts, where descending air is dry. The trade winds blow from the east and reach the western sides after losing their moisture over land. Cold currents along the western coasts cool and stabilise the air, so it does not rise to give rain.
What are xerophytes? Give three of their adaptations.
Xerophytes are plants adapted to very dry conditions. They have long roots to reach groundwater, small waxy leaves or spines to reduce transpiration, and fleshy stems that store water, as in the cactus.
Why does a hot desert have a much larger diurnal range of temperature than an equatorial place?
The desert's clear sky and dry air allow strong heating of the bare ground by day and rapid loss of heat at night. In the Equatorial region clouds and moist air reduce daytime heating and trap heat at night.
Name the three seasons of the tropical monsoon climate in India, giving the months of each.
The hot dry season (March to May), the rainy season of the south-west monsoon (June to September), and the cool dry season of the north-east monsoon (October to February).
Past board exam questions
ICSE 2019 sample paper · 2 marks
With reference to the Natural regions of the world answer the following: (i) Why does the Taiga region not exist in the Southern hemisphere? (ii) Prairies are called the granaries of the world.
Show answer
(i) The Taiga lies between about 55° and 70° latitude. In the Southern hemisphere there is hardly any land in these latitudes (only ocean, apart from the tip of South America), so the Taiga region is absent.
(ii) The Prairies have vast level land, fertile black (chernozem) soil, moderate rainfall and a warm summer suited to wheat; with large mechanised farms they produce a huge surplus of wheat that is exported to many countries, so they are called the granaries of the world.
ICSE 2019 sample paper · 2 marks
Why are tropical deserts found along the western margins of the continents?
Show answer
The western margins of continents in the tropics (15°-30°) lie in the path of the off-shore trade winds, which blow from the land and have lost their moisture; cold ocean currents flowing along these coasts cool the air above and prevent it from rising, so there is hardly any rainfall - hence deserts (e.g. Sahara, Kalahari, Atacama).
ICSE 2019 sample paper · 2 marks
Name the economic activities practised in the tropical grasslands.
Show answer
Cattle rearing / pastoralism (nomadic herding by tribes such as the Masai), hunting, and agriculture - growing crops such as maize, millets, groundnut, cotton, sugarcane, tobacco and coffee; also tourism (game parks and safaris).
ICSE 2019 sample paper · 3 marks
Give a reason for each of the following: (i) “The Equatorial region is also called the lungs of the world.” (ii) The trees found in the Mediterranean region have long roots and thick barks. (iii) Tundra region has a low annual range of temperature.
Show answer
(i) The Equatorial region has the densest evergreen rainforests in the world; these absorb large quantities of carbon dioxide and release huge amounts of oxygen, just as lungs supply oxygen to the body.
(ii) The Mediterranean region has hot, dry summers when there is no rain; trees have long roots to draw water from deep below the ground and thick barks to reduce loss of water (transpiration) during the dry summer.
(iii) The Tundra lies in high latitudes where it is cold throughout the year; the summers are short and cool, and the winters very cold, so the difference between the summer and winter temperatures is small.
ICSE 2019 sample paper · 3 marks
(i) What type of climate is experienced in the north-western part of Europe? (ii) What is the human response to the typical climate of this region?
Show answer
(i) North-western Europe has a cool temperate western margin (British type) climate: mild winters and cool summers, with rainfall throughout the year from the westerlies (and the warm North Atlantic Drift).
(ii) People practise dairy farming (fodder crops and grass grow well), mixed farming and growing of crops like wheat, barley, oats and sugar beet, as well as market gardening; lumbering in the forests; fishing on the continental shelves (Dogger Bank); the mild climate also favours industries and dense population.