JAC Board Class 7 Social Science Notes Geography Chapter 8 Human Environment Interactions: The Tropical and the Subtropical Regions
→ Life in the Amazon Basin:
- The river Amazon flows through the equatorial region between 10°N and 10°S.
- River’s mouth is the place where a river flows into another body of water.
- Number of tributaries join the Amazon River to form the Amazon basin. The river basin drains portions of Brazil, parts of Peru, Bolivia, Ecuador, Columbia and a small part of Venezuela.
- The Amazon Basin has been characterized by hot and wet climate throughout the year. Day and nights both are almost equally hot and humid. The skin feels sticky.
- Rain occurs almost everyday. The temperatures of daytime are high with very high humidity. The temperature during night goes down but the humidity remains high.
In this region, heavy rainfalls happen. Hence, the forests are very thick that the dense ‘roof’ are created by the leaves and branches which does not allow the sunlight to reach the ground.
- Orchids, bromeliads grow as plant parasites as only shade tolerant vegetation may Birds which are found are toucans, humming birds, bird of paradise with their brilliantly coloured plumage, oversized bills for eating make them different from birds we commonly see in India. These birds make loud sounds in the forests. These forests are very rich in fauna.
- Monkeys, sloth and ant-eating tapirs are found in this forest. Different species of reptiles and snakes such as crocodiles, snakes, pythons are also found. Anaconda and boa constrictor are some of the species which are found here.
- It is the home for various kinds of insects. Many species of fishes such as the flesh eating Piranha fish is also found in the river. Hence, this basin is exceptionally rich in the variety of life found there.
→ People of the Rainforests
- Most of the food are grown in small places after clearing some trees in the forest. Men usually hunt and fish along the rivers and women take care of the crops.
- They mainly grow tapioca, pineapple and sweet potato. The women take care of their families alive by growing vegetables as hunting and fishing are uncertain.
- They practice ‘slash and bum agriculture’ which is a way of cultivating land where farmers clear a piece of land by slashing or cutting down trees and bushes and then they are burnt.
- Manioc which is also known as cassava that grows under the ground like the potato is the staple food. They also eat queen ants and egg sacs. Coffee, maize and cocoa are also grown which are the cash crops.
- Some people live in thatched houses shaped like beehives. Some live in large apartment like houses are known as ‘Maloca’ with a steeply slanting roof.
- In the older days, only by navigating the river the core of the forest could be reached. In 1970, all parts of the rainforest was made accessible by the Trans Amazon highway. Aircrafts and helicopters are also used for reaching the remote places.
- In the Amazon basin, it is evaluated that a large area of the rainforest has been disappearing annually.
- Due to destruction of forest, the topsoil is washed away as the rains fall and the lush forest turns into a barren landscape.
→ Life in the Ganga-Brahmaputra Basin
- Ganga-Brahmaputra basin in the Indian subcontinent is formed by the tributaries of rivers Ganga and Brahmaputra together. This basin lies in the sub-tropical region which is situated between 10°N to 30°N latitudes.
- The River Ganga has the tributaries such as the Ghaghra, the Son, the Chambal, the Gandak, the Kosi and the tributaries of Brahmaputra drain it.
- The main features of this basin are the plains of the Ganga and the Brahmaputra, the mountains and the foothills of the Himalayas and the Sundarbans delta.
- The monsoon climate is the main climate of this region. The monsoon brings rains from mid-June to‘mid-September. Hence, the summers are hot and the winters cool.
- The environment plays a major role in the distribution of the population. Inhospitable terrain is mostly found in the mountain areas with steep slopes. Hence, population is less who live in the mountain area of the Ganga-Brahmaputra basin.
- Human habitation is present in the plain area which is the most suitable land as the soil is fertile. The main occupation of the people is agriculture where flat land is available to grow crops.
- The density of population of the plains is very high. Paddy is the main crop as the cultivation of paddy requires sufficient water, so it is grown in the regions where there is high rainfall.
- The other crops which are grown here are wheat, maize, sorghum, gram and millets. Sugarcane and jute are the cash crops which are also grown. In some areas of the plain, banana plantations are found.
→ Tea is grown in West Bengal and Assam.
In some parts of Bihar and Assam, silk is produced through the cultivation of silk worms. Crops are grown on terraces in the mountains and hills, where the slopes are gentle.
- In the Ganga and Brahmaputra plain tropical deciduous trees grows such as teak, sal and peepal. In the Brahmaputra plain, thick bamboo groves are very common. The delta region is covered with the mangrove forests.
- In some parts of Uttarakhand, Sikkim and Arunachal Pradesh, coniferous trees such as pine, deodar and fir can be found. The climate is cool and the slopes are steep.
- Many animals are found in this basin. Elephants, tigers, deer and monkeys are found. In the Brahmaputra plain, the one-homed rhinoceros is found. In the delta region, Bengal tiger, crocodiles and alligator are found. Aquatic life are found in the fresh river waters, the lakes and the Bay of Bengal Sea. The most popular varieties of the fish are the rohu, catla and hilsa.
→ The staple diet of the people living in this region are fish and rice.
- Several big towns and cities are present near the Ganga-Brahmaputra plain. The main cities are Prayagraj, Kanpur, Varanasi, Patna and Kolkata with the dense population which are located along the River Ganga.
- The wastewater and garbage from these cities and industries is discharged into the rivers which leads to the pollution of the rivers.
- In the Ganga-Brahmaputra basin, all the means of transport are well developed. In the plain areas, the people use the roadways and railways transport to move from one place to another. The waterways, is an important means of transport particularly along the rivers. Kolkata is an important port on the River Hooghly. Large number of airports are present in the plain areas.
- The other important activity of the basin is tourism. Taj Mahal on the banks of River Yamuna in Agra, Prayagraj on the confluence of the Rivers Ganga and Yamuna and invisible Saraswati river which is known as Triveni Sangam, Buddhist stupas in Uttar Pradesh and Bihar, Lucknow with its Imambara, Kaziranga and Manas wild life sanctuaries in Assam and Arunachal Pradesh has a distinct tribal culture which are some of the places worth a visit.