Human Environment Interactions the Tropical - Revision Notes

 CBSE Class 07 Social Science

Revison Notes
Chapter – 8 Geography

Human Environment Interactions: The Tropical and the Subtropical Region

• Human beings interact with the environment and are dependent on it for a number of things. The natural environment provides human beings with resources for their existence.

• Life in the Amazon Basin:

(i) Amazon river was discovered by a Spanish explorer, Vicente Yanez Pinzon. When Spanish explorers discovered the Amazon river, they 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, they named the river Amazon.

(ii) The Amazon basin lies in the tropical region of South America close to the equator between 10 degree North and 10 degree South, and the river Amazon flows through this region.

(iii) The Amazon river basin drains portions of Brazil, parts of Peru, Bolivia, Ecuador, Columbia and a small part of Venezuela.

(iv) The place where a river flows into another body of water is called the river’s mouth. Numerous tributaries join the Amazon River to form the Amazon basin.

• Climate:

(i) The Amazon basin stretches directly on the equator and it is characterized by hot and west climate throughout the year.

(ii) There is heavy rainfall and high humidity.

(iii) It rains almost everyday, that too without much warning.

(iv) The day temperatures are high with very high humidity. At night, the temperature goes down but the humidity remains high.

• Rainforest:

(i) As it rains heavily, thick forests grow in this region.

(ii) The forests are in fact so thick that the dense roof created by leaves and branches do not allow the sunlight to reach the ground.

(iii) The rainforest is rich in fauna.

  • Birds such as 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 also make loud sounds in the forests.
  • Animals like monkeys, sloth and ant-eating tapirs are found here. Various species of reptiles and snakes also thrive in these jungles. Crocodiles, snakes, pythons abound. Anaconda and boa constrictor are some of the species.
  • The basin is home to thousands of species of insects.
  • Several species of fishes including the flesh eating Piranha fish are also
    found in the river.

• People of the Rainforests:

(i) People grow most of their food in small areas after clearing some trees in the forest. While men hunt and fish along the rivers, women take care of the crops.

(ii) Slash and burn agriculture is prevalent. The crops grown are tapioca, pineapple and sweet potato.

(iii)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.

(iv) The development activities are leading to gradual destruction of the biologically diverse rainforest.

(v)The rain-forests provide a lot of wood for the houses. Some families live in thatched houses shaped like beehives. There are other large apartment-like houses called “Maloca” with a steeply slanting roof.

• Life in the Ganga-Brahmaputra Basin:

(i) The tributaries of rivers Ganga and Brahmaputra together form the Ganga-Brahmaputra basin in the Indian subcontinent.

(ii) 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.

(iii) The plains of the Ganga and the Brahmaputra, the mountains and foothills of the Himalayas and the Sunderbans delta are the main features of this region.

(iv) Ox-bow lakes dot the plain area. The area is dominated by monsoon climate. The
monsoon brings rains from mid-June to mid-September. The summers are hot and the winters cool.

(v) The basin area has varied topography. The mountain areas with steep slopes
have inhospitable terrain. Therefore, less number of people live in the mountain area of the Ganga- Brahmaputra basin. The plain area provides the most suitable land for human habitation. The soil is fertile.

(vi) Agriculture is the main occupation of the people where flat land is available to grow new crops.

(vii) Wheat, maize sorghum, gram and millet are the important crops of the region. Banana plantations are seen in some areas of the plain. In West Bengal and Assam tea is grown in plantations. Silk is produced through the cultivation of silk worms in parts of Bihar and Assam.
In the mountains and hills, where the slopes are gentle, crops are grown on terraces.

(vi) The vegetation cover of the area varies according to the type of landforms. 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 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.

(vii) There is a variety of wildlife in the basin. In the delta areas, Bengal tiger, crocodiles and alligators are found. Elephants, tigers, deer and monkeys are common. The one-horned
rhinoceros is found in the Brahmaputra plain. 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.

(viii) Fish and rice is the staple diet of the people.

(ix) The Ganga-Brahmaputra plain has several big towns and cities like Allahabad, Kanpur, Varanasi and Lucknow.

(x) All the four means of transport are well-developed in the Ganga-Brahmaputra basin.

(xi) Tourism is an important activity of the region. Taj Mahal on the banks of River Yamuna in Agra, Allahabad on the confluence of the Rivers Ganga and Yamuna, Buddhists stupas in Uttar Pradesh and Bihar, Lucknow with its Imambara, and Assam with Kaziranga are some of the places worth visiting.