NCERT Class 7 Geography Chapter 10: Life in Deserts Completes Notes Part 1

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Life in Deserts

Now when we started with the initial chapter we talked about the three basic system as the forest, grass lands and the shrugs. Then we talk about the desert areas so desert are typically of two types, hot deserts and cold deserts. In today session will be dealing with one case study from each of this, that’s the hot desert and the cold deserts.

Now I have been asked with numerous queries regarding. Are these the only things that we have to study for the competitive examination? My answer is definitely no because as we move forward will have further areas on which we will be studying so the case studies will automatically increase with higher classes.

Characteristics

  • Extreme High and Low Temperature

  • Scarce Vegetation

  • Low Rainfall

  • Types – Hot & Cold

Now what are the basic characteristics of a desert. Definitely there are extreme of temperature during the day time there is extremely high temperature. However during the night there is extremely low temperature. In winters the night even reach the freezing temperature in many areas. Now vegetation in the desert is mainly scares you have the main vegetation that’s in the form of Cactus and in Cactus if you see you have the modification of stem to leave and leaves to thorn that’s the commonly seen modification in the trees and that is the main idea is to reduce the water through transpiration. The reason definitely has low rainfall as a result you have the modification that you see here in the vegetation. Now when we will start with the case studies, there would be two case studies that we would be discussing. One is hot deserts and another is for cold deserts.

Sahara (Hot Desert)

Location of Sahara Desert on World Map

Location of Sahara Desert on World Map

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  • In N. Africa

  • World’s Largest Desert

  • Area – 8.54 Million Sq. Km.

  • 11 Nations – Algeria, Chad, Libya, Mali, Mauritania, Morocco, Niger, Sudan, Tunisia, W. Sahara

  • Sand, Plain Gravels, Elevated Plateaus

  • At one time it was lush green – Now climate changed

  • Highest Temperature – Al Azizia (Tripoli, Libya 57.7oC in 1922)

For Hot deserts will talk about Sahara desert in Africa and for cold desert will talk about the Ladakh desert in India. Now Sahara, you have the northern region that is the Sahara desert. Now this is the world’s largest desert area with an area of 8.54 million sq.km. There are 11 countries that are affected by Sahara desert that is Algeria, Chad, Libya, Mali, Mauritania, Morocco, Niger, Sudan, Tunisia, W. Sahara. The topography here is mainly Sand, Plain Gravels, Elevated Plateaus and few areas. Now this has been a result of climate change that has been taken place over the years, millions of years back this area was a lush green forest area or a region with very good vegetation but with the changes in the climate that happened this region turned out to be a desert area and that was the climatic change that has taken place over the years. In Sahara desert in 1922 the highest temperature was recorded at Al Azizia in Tripoli, Libya 57.5oC.

  • Short rain

  • Cloudless and clear sky

  • Nights freezing cold with zero degree

  • Cactus, Date Palms & Acacia

  • Oasis – Water – Depression (Tafilalet Oasis – 13000 Sq. km.)

  • Camels, Hyena, Jackals, Fox, Scorpions, Snakes & Lizards

  • Oil – Algeria, Egypt & Libya

  • Iron, Phosphorous, Magnesium, Uranium

This region definitely has short rainfall, they sky is cloudless and clear night are freezing cold with temperature rising up to zero degree, the major vegetation is Cactus, Date Palms & Acacia. Cactus is the major vegetation that seen through the desert area date palms are seen close to the region of Oasis. Now what is Oasis? Oasis is this is a water body that is found in a desert area. It’s a kind of depression so when we talk about when we work around with the Aeolian landforms we talked about the formation the erosional features and out of that one was depression. Now this depression is filled with water and that forms an Oasis in the desert area the oasis the region to the Oasis or surrounding the oasis has kind of date palms trees and you have small settlement that is close to Oasis. As a result settlement pattern in the desert area is primarily circular.

Now the famous Oasis is Tafilalet which is an area of 13,000 Sq. km. The common animals seen in deserts are Camels, Hyena, Jackals, Fox, Scorpions, Snakes & Lizards out of this camel has a capacity to store water and food for many days. Sahara in itself is rich with minerals and resources so among the mineral resource the common resources are Iron, Phosphorous, Magnesium, Uranium. It is also rich oil producing area with Algeria, Egypt & Libya. Now about the tribes.