The compilation of these Life in the Deserts Notes makes students exam preparation simpler and organised.
The Hot Desert – Sahara
We are sure you all know what deserts are. Isn’t it? How many of you have actually been to a desert and know how it is like? Have you ever wondered how people live in a desert and what they eat? In this chapter, we will look at one of the most famous deserts in the world, the Sahara Desert.
What is a Desert?
A desert is an arid region characterized by extremely high or low temperatures, low rainfall, and scarce vegetation. You would also find a scarcity of water. It is very difficult to live in a place where there is no water to drink, no grass to feed the cattle and no water for the growth of grass.
It is a wonder that people who live in the deserts have learned to cope up with extremely harsh climates. Depending on the temperature, we can find hot deserts or cold deserts. People inhabit these lands wherever little water is available to practice agriculture. In this chapter, we will discuss the desert of Sahara.
The Sahara Desert
The Sahara desert covers a large part of North Africa. It has the following features:
- Sahara is the world’s largest desert. It covers an area of around 8.54 million square kilometers (which is more than the total area of India!!).
- The desert touches eleven countries which are as follows: Algeria, Morocco, Chad, Egypt, Libya, Mali, Mauritania, Niger, Sudan, Tunisia, and Western Sahara.
- It has gravel plains and elevated plateaus with a bare rocky surface. These rocky surfaces, at some places, are more than 2500 m high.
Climate
The climate of the Sahara desert is scorching hot and parched dry. It has a short rainy season. Since the sky is cloudless and clear, the rate of water evaporation is greater than the rate of water accumulation. Hence, there is water scarcity. However, the nights may be freezing cold with temperatures nearing zero degrees Celsius.
Flora and Fauna
Flora: Vegetation in the Sahara desert includes cactus, date palms and acacia. We can find an oasis in some places.
Fauna: The animal species found here are camels, hyenas, jackals, foxes, scorpions and many varieties of snakes and lizards.
People of the Sahara Desert
Different groups of people inhabit the Sahara desert. They are engaged in different activities. Among them are the Bedouins and the Tuaregs. These groups are nomadic tribes. They wear heavy robes to protect them from the harsh climate i.e. dust storms and hot winds. The tribes are engaged in animal rearing. Animals such as sheep, goats, camels, and horses are reared for the following purposes:
- Milk
- Hides: These are used to make leather for belts, slippers, and water bottles.
- Hair: This is used to make mats, carpets, clothes, and blankets.
Growing Date Palms and Agriculture
The oasis in the Sahara and Nile valley in Egypt supports a settled population. Since water is available, people grow date palms. Other crops that are grown include rice, wheat barley, and beans. Egyptian cotton is grown in Egypt.
Changes in the Desert
Sahara desert is experiencing constant transformation because of the discovery of oil. This discovery has been made in Libya and Egypt etc. We can also find other important minerals like iron, phosphorus, manganese, and uranium.
- We also find a lot of changes caused due to business and infrastructural development.
- Gleaming glass-cased office buildings tower over mosques and superhighways crisscross the ancient camel paths.
- Trucks are replacing camels in the salt trade.
- Tuaregs are seen acting as guides to foreign tourists.
- Many nomadic tribes are finding jobs in the field of oil and gas operations, and migrating to cities.
What is a Mirage?
Under a baking sun, a weary traveller trudges across a seemingly never-ending expanse of desert. Looking up, he suddenly spots something in the distance: a sparkling lake. He rubs his eyes. It’s still there. Picking up the pace in glee he strides ahead… only for the water to melt into thin air. Doesn’t that sound fun?
Well, it actually is science! Mirages are a naturally occurring optical illusion. In cartoons, a mirage is often depicted as a peaceful, lush oasis lying in the shade of swaying palm trees, but in reality, it is much more likely to look like a pool of water.
The illusion results from a way in which light is refracted (bent) through the air at different temperatures. Cold air is denser than warm air and therefore has a greater refractive index. This means that as light passes down from cool to hot air. It gets bent upwards towards the denser air and away from the ground.
To your eyes, these distorted rays seem to be coming from the ground, so you perceive a refracted image of the sky on the ground. This looks just like a reflection on the surface of a pool of water. This causes confusion.
Example:
Question:
What is an Oasis?
Answer:
In the depressions (which are formed when the wind blows away the sands) where underground water reaches the surface; an oasis is formed. These areas are fertile. People may settle around these water bodies. People may grow date palms and other crops. Sometimes the oasis may be abnormally large.