Human Environment Interactions | Class 7 | CBSE

Chapter 8

Class 7 Social Science : Geography Chapter 8

Human Environment Interactions- the tropical and the subtropical Regions

Life in the Amazon Basin

A basin is a portion of land which is drained by a river and its tributaries. The Amazon Basin is drained by the River Amazon- the second longest river in the world. The river basin drain parts of Brazil, Peru, Ecuador, Bolivia, Columbia and a small portion of Venezuela into the Atlantic Ocean.

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Climate

The Amazon Basin is also called the equatorial region as it lies very close to the Equator. It is located between 10°N and 10°S.
Since the Amazon Basin lies in the equatorial regions, it has a hot and wet climate throughout the year. Both the days and nights are equally hot and humid here.
Rainfall occurs almost every day.
The day temperatures are very high while the nights are cooler but with high humidity.

Rainforests

Since heavy rainfall occurs daily, the region has a thick forest cover. At some places, the forests are so dense that sunlight is unable to reach the ground. Hence, the ground remains dark and damp.
The Amazon rainforests are known for their wide variety of fauna. Toucans, colourful parrots, and humming birds are largely found in these forests.
Animals such as monkeys, tapirs and sloths are also commonly found in the rainforests.
Various species of reptiles and snakes are also found in this region including anacondas and boa constrictors, which are two species of snakes.
Many varieties of small insects are also found in these forests. The Amazon Basin is a home of several species of fishes. Piranha- the flesh eating fish is also found in this region.

People

People in this region grow their food in small areas after clearing a patch of forests usually using slash and burn cultivation.
In this kind of cultivation, farmers first cut down the trees and burn them. The ashes of the burnt trees release nutrients into the soil making it fertile. Crops are then planted into the cleared area. After a few years of cultivation, the land loses its fertility and hence the farmers abandon the land and clear another patch of land for cultivation.

The staple food of the people is manioc, also known as cassava which grows underground like potato.
People also eat queen ants and egg sacs.
Cash crops which are grown here are coffee, maize and cocoa.
People live in houses called ‘maloca’ which have a slanting roof.
The lives of people in the Amazon Basin is changing fast. The construction of the Amazon Highway has made all parts of the basin accessible.
The commercial use of wood has forced the people to settle in new areas of the forest where they continue to practice slash and burn cultivation.
Heavy deforestation has been taking place in the rainforests due to the rising demand of commercial wood. Deforestation has also resulted in soil erosion as the top layer of soil gets washed away due to indiscriminate cutting off of trees.

Life in the Ganga-Brahmaputra Basin

The Ganga Brahmaputra Basin lies in the subtropical region located between 10°N to 30°S. The basin is drained by the tributaries of the River Ganga and River Brahmaputra. They drain the north and northeastern part of India which includes the Northern Indian Plains, foothills of the Himalayan regions and the Sunderban Delta.

Climate

The Ganga-Brahmaputra region has the monsoon type of climate. Rainfall occurs from the mid of June to the mid of September.
The summers here are hot while the winters are cold.

Topography and Vegetation

The topography or the relief features of this region vary greatly.
While the Northern Indian Plains have fertile lands, the mountainous areas have a hostile terrain. Therefore, the density of population in the plain region is very high while it is extremely low in the mountainous regions.
In the Ganga-Brahmaputra Basin, tropical deciduous forests grow. Teak, sal and peepal are the main species of trees found here.
Sunderbans in the Brahmaputra Basin forms the largest delta in the world. The Sunderbans have the mangrove forests. sundari is the common species of trees found here.
In the Himalayan regions, i.e., in parts of Uttarakhand, Sikkim and Arunanchal Pradesh, coniferous trees grow. Some commonly found species of trees here are deodar, pine and fir.

People and their Occupation

The plain region of the Ganga-Brahmaputra Basin is densely populated because of the fertile soi l and flat land.
The chief occupation of the people is cultivation.
Rice or paddy is the main crop which is grown in this region. Wheat, sorghum, maize, gram and millets are the other crops which are grown here.
Sugarcane and jute are the two cash crops grown in the region. Tea is grown in Assam and West Bengal. Silk is cultivated by the rearing of silk worms in Bihar and Assam.
In the hilly regions, terrace farming is practised.
Tourism is another important occupation of the people in the region. The Taj Mahal attracts thousands of tourists from across India and abroad.
Allahabad located on the confluence of rivers Ganga and Yamuna is visited by many pilgrims from all over the country.
Buddhist Stupas in Bihar and Uttar Pradesh and historical buildings in Lucknow are also visited by many tourists.
The Kazirangha and Manas wild life sanctuary in Assam is a popular tourist attraction.

Wild Life

The Ganga-Brahmaputra Basin has a rich wildlife. The one horned rhinoceros is found in the Brahmaputra Plains.
Elephants, deer and monkeys are commonly found in this region.
The Royal Tiger of Bengal is found in the Sunderban Delta.
Crocodiles and alligators are some common reptiles which are found in the delta region.
Rohu, hilsa and catla are the common varieties of fishes that are found in the region.
In fresh waters of river Ganga and Brahmaputra, a local species of dolphin called Susu or the blind dolphin are commonly found. However, an increase in the industrial effluents is resulting in a decrease in the number of dolphins.

Cities and Transport

Many known cities are situated in the Ganga-Brahmaputra Basin. The cities of Allahabad, Varanasi, Lucknow, Kolkata and Patna have a population of more than one million people. These cities are located along the River Ganga.
The discharge of liquid wastes from the industries located in these cities has polluted the water of the River Ganga.
All the cities and towns of the Ganga-Brahmaputra Basin are well connected to each other by all the four means of transport.
While roads and railways have connected the cities located in the plains, water transport has developed along the river systems. Kolkata is an important port located on the River Hooghly.