CBSE Class 7 Social Science Geography Chapter 9: Life In The Deserts Notes

The Hot Desert: Sahara

The Sahara Desert is the world's largest desert, covering a massive area of North Africa across eleven countries (including Algeria, Egypt, Libya, Mali, and Sudan). It features vast stretches of sand, gravel plains, and elevated plateaus with bare rocky surfaces.

The climate of Sahara is scorching hot and dry. It has a short rainy season, and the sky is cloudless and clear. Moisture evaporates faster than it accumulates. Temperatures during the day can soar up to 50°C, heating the sand and rocks, which in turn radiates heat. At night, temperatures can plunge to freezing point near 0°C.

Despite the harsh climate, specialized flora and fauna survive here. Vegetation includes cactus, date palms, and acacia. In places where underground water reaches the surface, oases are formed. Animal species include camels, hyenas, jackals, foxes, scorpions, and various snakes.

The Cold Desert: Ladakh

The cold desert of Ladakh lies in the Great Himalayas, on the eastern side of Jammu and Kashmir. It is nestled between the Karakoram Range in the north and the Zanskar mountains in the south.

Its altitude varies from about 3,000m in Kargil to more than 8,000m in the Karakoram. Due to this high altitude, the climate is extremely cold and dry. The air is so thin that the heat of the sun is felt intensely. Summers are cool with daytime temperatures just above 0°C, while nights drop below -30°C. Winters are freezing cold, often staying below -40°C.

Because it lies in the rain shadow of the Himalayas, Ladakh receives very little rainfall (about 10 cm annually). Vegetation is sparse, consisting of thin patches of grass and shrubs. Groves of willows and poplars grow in valleys. The fauna includes wild goats, wild sheep, yaks, and dogs. Ladakh is also a home to migratory birds like Robins, Redstarts, and Hoopoes.

Comparison: Sahara vs. Ladakh

Glossary of Key Terms

Desert

An arid region characterized by extremely high or low temperatures, low rainfall, and scarce vegetation.

Oasis

A fertile green depression in a hot desert where underground water reaches the surface, allowing cultivation and settlement.

Khapa-chan

The local name for Ladakh, which literally translates to 'snow land'.

Shahtoosh

An extremely light, warm, and highly valuable wool harvested from the endangered Tibetan Antelope (Chiru).

Gompas

Traditional Buddhist monasteries found in Ladakh, often featuring distinctive architecture.

Rain Shadow Area

An area having relatively little precipitation because it is sheltered from rain-bearing winds by a range of hills or mountains.

Must Remember Key Points

• The Sahara is the world's largest hot desert, covering an area of about 8.54 million square kilometers.
• Oases in Sahara are formed when wind blows away the top sand, creating depressions where the water table is reached.
• Bedouins and Tuaregs are two major nomadic tribes in Sahara that trade livestock products like hides, wool, and milk.
• Discovery of oil in countries like Algeria, Libya, and Egypt has rapidly transformed the traditional lifestyle of the Sahara.
• Ladakh ranges in altitude from 3,000m to 8,000m, causing intense solar radiation and thin atmospheric pressure.
• The Gangri Glacier is one of the primary glaciers situated in the cold desert of Ladakh.
• Yaks are highly valued in Ladakh; their milk is used to make cheese and butter, and their hair is used for tents and woolens.
• The Leh-Manali Highway crosses four high altitude passes: Rohtang La, Baralacha La, Lungalacha La, and Tanglang La.

Exam Cues and High-Yield Tips

1. Map Questions: Prepare the map of Africa to point out the Sahara Desert and name at least three neighboring countries. Algeria, Libya, and Egypt are the easiest to remember.
2. The Chiru Trap: In short-answer questions, students often write that Shahtoosh comes from sheep. Remember, it comes from the Tibetan Antelope (Chiru), which is hunted illegally for this fine wool.
3. Monastery Examples: When writing about Ladakh's culture, always mention 'Gompas' and cite famous examples like Hemis, Thiksey, Shey, and Lamayuru to secure full marks.

Quick Revision Check

• Why do people of the Sahara desert wear heavy robes? People of the Sahara desert wear heavy robes as a protective measure against dust storms, scorching dry winds, and extreme heat during the day, as well as the abrupt cold at night.
• What crops are cultivated in the cold desert of Ladakh during summers? During the summer season, when the ice melts, people in Ladakh cultivate crops like barley, potatoes, peas, beans, and turnips.
• What major minerals are found in the Sahara Desert? The Sahara is rich in oil (mined in Algeria, Libya, and Egypt). Other important minerals found in the region include iron, phosphorus, manganese, and uranium.
• Describe the main factors that make Ladakh a rain-shadow region. Ladakh is situated on the eastern side of the high-altitude Great Himalayas. This mountain barrier blocks rain-bearing monsoon clouds from reaching the region, resulting in less than 10 cm of rainfall annually.

Frequently Asked Questions