- Books Name
- CBSE Class 7 Social Science Book
- Param Publication
- CBSE Class 7
- Social Science
The chapter deals with the life of the people and their culture and economic activities in the tropical and subtropical regions. We can find out the role of forests and the land in the economic life of the people living in these areas.
* Life in the Amazon Basin
(i) Notice that the tropical region lies very close to the equator, between 10°N and 10°S. So, it is referred to as the equatorial region.
(ii) The river Amazon flows through this region. It flows from the mountains to the west and reaches the Atlantic Ocean to the east.
(iii) The place where a river flows into another body of water is called the river’s mouth.
(iv) Numerous tributaries join the Amazon River to form the Amazon Basin.
(v) The river basin drains portions of Brazil, parts of Peru, Bolivia, Ecuador, Columbia and a small parts of Venezuela.
(vi) Amazon river basin is the largest river basin in the world.
(i) Has hot and wet climate throughout the year.
(ii) Both day and nights are almost equally hot and humid.
(iii) Day temperatures are high with very high humidity.
(iv) In night the temperature goes down but the humidity remains high.
(i) Due to heavy rains thick forests grow.
(ii) The ground remains dark and damp because forest are so dense that “roof” created by leaves and branches does not allow the sunlight to reach the ground.
(iii) Only shade tolerant vegetation may grow.
(iv) Orchids, bromeliads (special plants which store water in their leaves) grow as plant parasites.
(v) Rich in fauna such as toucans humming birds, bird of paradise with their brilliantly coloured plumage and oversized bills.
(vi) Also animals like monkeys, sloth and ant-eating tapirs are found here. Various species of reptiles and crocodiles, snakes also thrive in these jungles.
(vii) It is also home to many insects and fishes including flesh eating Piranha fish.
* People of the Rainforests
(A) ⇒ People grow most of their food in small areas after clearing some trees in the forest. While men hunt and go for fishing along the rivers, women take care of the crops.
⇒ They mainly grow tapioca, pineapple and sweet potato. As hunting and fishing are uncertain it is the women who keep their families alive by feeding them the vegetables they grow.
⇒ They practice “slash and burn agriculture”. The staple food is manioc, also known as cassava that grows under the ground like the potato. They also eat queen ants and egg sacs. Cash crops like coffee, maize and cocoa are also grown.
(B) The rainforests provide a lot of wood for the houses. Some families live in thatched house shaped like beehives. There are other large apartment-like houses called “Maloca” with a steeply slanting roof.
(C) Life of the people of the Amazon basin is slowly changing. In the older days the heart of the forest, could be reached only by navigating the river. In 1970 the Trans Amazon highway made all parts of the rainforest accessible. Aircrafts and helicopters are also used for reaching various places. The indigenous population was pushed out from the area and forced to settle in new areas where they continued to practice their distinctive way of farming.
(D) The development activities are leading to the gradual destruction of the biologically diverse rainforests. It is estimated that a large area of the rainforest has been disappearing annually in the Amazon basin. The topsoil is washed away as the rains fall and the lush forest turns into a barren landscape.
* Life in the Ganga-Brahmaputra Basin
(i) This basin lies in the sub-tropical region that is situated between 10°N to 30°N latitudes.
(ii) The tributaries of rivers Ganga like the Ghagra, the Son, the Chambal, the Gandak, the Kosi and the tributaries of Brahmaputra drain forming the Ganga-Brahmaputra basin in the Indian subcontinent.
(iii) 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. Also the Ox-bow lakes dot the plain area.
(iv) The area is dominated by monsoon climate which brings rains from mid-June to mid-September. The summers are hot and the winters cool.
(v) Therefore less number of people lives in the mountain area of the Ganga-Brahmaputra Basin because the mountain areas with steep slopes have inhospitable terrain.
(vi) The plain area provides the most suitable land for human habitation because the soil is fertile and agriculture is the main occupation of the people.
(vii) The main crop is paddy. Other crops grown include wheat, maize, sorghum, gram and millets.
(viii) Cash crops like sugarcane and jute are also grown.
(ix) Banana plantations are seen in some areas of the plain.
(x) Other plantation includes tea (in West Bengal and Assam).Silk is produced through the cultivation of silk worms in parts of Bihar and Assam.
(xi) In the ganga and Brahmaputra plain tropical deciduous trees grow, along with teak, sal and peepal. Thick bamboo groves are common in the Brahmaputra plain. The delta area is covered with the mangrove forests. In parts of Uttaranchal, Sikkim and Arunachal Pradesh, Coniferous trees like pine, deodar and fir can be seen because the climate is cool and the slopes are steep.
(xii) Elephants, tigers, deer and monkeys are common in basin. The one-horned rhinoceros is found in the Brahmaputra plain. In the delta area, Bengal tiger, crocodiles and alligator are found. Aquatic life abounds 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.
(xiii) Fish and rice is the staple diet of the people living in the area.
(xiv) The cities of Allahabad, Kanpur, Varanasi, Lucknow, Patna and Kolkata all with the population of more than ten lakhs are located along the river Ganga. The wastewater from these towns and industries is discharged into the rivers. This leads to the pollution of the rivers.
(xv) All the four ways of transport are well developed in the Ganga-Brahmaputra basin. In the plain areas the roadways and railways transport the people from one place to another. The waterways, is an effective means of transport particularly along the rivers. Kolkata is an important port on the river Hooghly. The plain area also has a large number of airports.
(xvi) Tourism is another important activity of the basin. Taj Mahal on the banks of river Yamuna in Agra, Allahabad on the confluence of the rivers Ganga and Yamuma, Buddhists stupas in Uttar Pradesh and Bihar, Lucknow with its Imambara, Assam with Kaziranga and Manas with wild life sanctuaries and Arunachal Pradesh with a distinct tribal culture are some of the places worth a visit.
* Interesting Facts:
1. Spanish explorers discovered Amazon river and were attacked by a group of local tribes wearing headgears and grass skirts. These people reminded them of the fierce tribes of women warriors known in ancient Roman Empire as the Amazons. Hence named Amazon.
2. Tributaries: These are small rivers that join the main river. The main river along with all its tributaries that drain an area form a river basin or the catchment area.
3. Slash and Burn is a way of cultivating land where farmers clear a piece of land by slashing or cutting down trees and bushes which are burnt, and releases the nutrients into the soil. Crops are now grown in this cleared field for a few years. After repeatedly using the patch of land, the soil loses its nutrients. So it is abandoned. Then they clear another plot of land to plant. In the mean time young trees grow in the old field. In this way soil fertility is restored. People can then return to it and start cultivating it again.
4. Population density: It means the number of persons that live in one sq. km of area e.g. the population density of Uttaranchal is 159 while the density of West Bengal is 904 and that of Bihar is 880.
5. Terraces are built on steep slopes to create flat surfaces on which crop are grown. The slope is removed so that water does not run off rapidly.
6. In the fresh waters of River Ganga and River Brahmaputra, a variety of dolphin locally called Susu (also called blind dolphin) is found. The presence of Susu is an indication of the health of the river. The untreated industrial and urban wastes with high amount of chemicals are killing this species.
* A case study
Lake : A source of Livelihood
Binod is a fisherman living in the Matwali Maun village of Bihar. He is a happy man today. With the efforts of the fellow fisherman - Ravindar, Kishore, Rajiv and others, he cleaned the maun or the ox-bow lake to cultivate different varieties of fish. The local weed (vallisneria, hydrilla) that grows in the lake is the food of the fish. The land around the lake is fertile. He sows crops such as paddy, maize and pulses in these fields. The buffalo is used to plough the land. The community is satisfied. There is enough fish catch from the river-enough fish to eat and enough fish to sell in the market. They have even begun supply to the neighbouring town. The community is living in harmony with nature. As long as the pollutants from nearby towns do not find their way into the lake waters, the fish cultivation will not face any threat.