Here is the class notes from Class 7 NCERT Geography- Chapter 8: Human Environment Interactions the Tropical and the Subtropical Region

LIFE IN THE AMAZON BASIN

  • Lies very close to the equator; between 10°N and 10°S.
  • The river basin drains portions of Brazil, parts of Peru, Bolivia, Ecuador, Columbia and a small part of Venezuela.
  • Flows from the mountains to the west and reaches the Atlantic Ocean to the east.
Climate
  • The Amazon Basin stretches directly on the equator and is characterized by hot and wet climate throughout the year.
  • Both day and nights are almost equally hot and humid.
  • The skin feels sticky.
  • It rains almost everyday, that too without much warning.
  • The day temperatures are high with very high humidity.
  • At night the temperature goes down but the humidity remains high.
Rainforests
  • The forests are in fact so thick that the dense “roof” created by leaves and branches does not allow the sunlight to reach the ground.
  • Only shade tolerant vegetation may grow here. Orchids, bromeliads grow as plant parasites.
  • This basin is thus extraordinarily rich in the variety of life found there.
  • Birds such as toucans, humming birds, birds of paradise with  their brilliantly coloured plumage is commonly seen here.
  • Animals- monkeys, sloth and ant-eating tapirs etc
  • Reptile- Crocodiles, snakes, pythons abound. Anaconda , boa constrictor etc
  • Flesh eating Piranha fish is also found in the river
People of the Rainforests
  • They practice “slash and burn agriculture”.
    • Slash and Burn is a way of cultivating land where farmers clear a piece of land by slashing or cutting down trees and bushes.
    • These are then burnt, which releases the nutrients into the soil. Now crops are grown in the area.
  • 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.
  • Houses called “Maloca” with a steeply slanting roof.
  • Life of the people of the Amazon basin is slowly changing.
  • 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.
  • The developmental activities are leading to the gradual destruction of the biologically diverse rainforests.

LIFE IN THE GANGA- BRAHMAPUTRA BASIN

  • The tributaries of rivers Ganga and Brahmaputra together form the Ganga-Brahmaputra basin in the Indian subcontinent.
  • The basin lies in the sub-tropical region that is situated between 10°N to 30°N latitudes.
  • The tributaries of the River Ganga like the Ghaghra, the Son, the Chambal, the Gandak, the Kosi and the tributaries of Brahmaputra drain it.
  • Main features of the Ganga- Brahmaputra basin
    • The fertile plains
    • The Himalayas
    • The Deltas of Sundarbans
  • Ox- bow lakes formed in the plain area.
  • The area is dominated by monsoon climate.
  • The soil is fertile.
  • Agriculture is the main occupation.
  • The main crop is paddy.
  • The density of population of the plains is very high.
  • Wheat, maize, sorghum, gram and millets are the other crops that are grown.
  • Cash crops like sugarcane and jute are also grown.
  • Banana plantations is also grown some areas of the plain.
  • In West Bengal and Assam tea is grown in plantations
  • 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.
  • In the foothills of Himalayas, coniferous trees like pine, deodar and fir can be seen because the climate is cool and the slopes are steep.
  • Elephants, tigers, deer, monkeys and one-horned rhinoceros is found in the Brahmaputra plain.
  • In the delta area, Bengal tiger, crocodiles and alligator are found.
  • The most popular varieties of the fish are the rohu, catla and hilsa is found in this area.
  • Fish and rice is the staple diet of the people living in the area.
  • In the fresh waters of River Ganga and River Brahmaputra, a variety of dolphin locally called Susu (also called blind dolphin) is found.
    • The untreated industrial and urban wastes with high amount of chemicals are killing this species.
  • On 02 October 2014, India launched “Swachh Bharat Mission” to achieve universal sanitation.
  • To conserve the river ganga, ‘Namami’ ganga Programme has been initiated.
  • Tourism is important activity of the basin.
  • Many national park and wildlife sanctuary is found here.
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