Tropical and Subtropical Regions (NCERT Class 7 Geography Chapter 8 Notes)

The region between Tropic of Cancer and Tropic of Capricorn is known as the tropical region. It is also known as the torrid region.

Amazon Basin

The region between 10°N and 10°S is known as the equatorial region. The Amazon river flows through this region. It is joined by numerous tributaries to form the Amazon basin. The Amazon basin is the largest river basin in the world and drains the part of Brazil, Peru, Bolivia, Equador, Columbia and  Venezuela.

The Amazon Basin is characterized by a hot and wet climate. The daytime temperature is high with high humidity and night temperatures are low but humidity levels remain the same. Moreover, it rains on a daily basis.

Flora and Fauna
The Amazon Rainforest is so thick that even sunlight does not reach the ground. Only shade tolerant vegetation found here. Orchids and bromeliads are grown as parasite plants.

The Amazon Rainforest is known for its rich fauna. Birds like toucans, hummingbird and bird of paradise are common here. Animals like monkeys, sloth and tapir thrive here. It is also known for snakes such as anaconda, boa constrictor and python. It is also home to several fish species. The flesh-eating Piranha also lives here.

Slash and burn type of agriculture is practised here. Farmers clear the land and burn the vestige. The nutrients are fixed by this process and the crops are cultivated on this land. After a few years, the land is left and vegetation is allowed to grow whereas another piece of land is cleared for agriculture. Manioc (cassava) is the staple food of the region. Other cash crops such as coffee, maize, and cocoa are grown here. They also practice fishing and hunting. They live in apartment-like wooden houses known as Maloca. In recent years, a major chunk of Amazon rainforest has lost due to development activities.

Amazon River Map
Amazon River Basin/Image Source: Wikimedia

Ganga-Brahmaputra Basin

Ganga and Brahmaputra along with their tributaries form the Ganga-Brahmaputra Basin. It lies between 10°N to 30°N. The Gangetic Plains, the Brahmaputra Plains, lower Himalayas and Sunderban delta are the main features of the Ganga-Brahmaputra Basin. Numerous ox-bow lakes can be found in the basin.

The Ganga-Brahmaputra Basin is marked by the monsoon climate. Most of the rain falls between June and September. Winters are cold and Summers are hot. The basin has varied topography. Therefore, one can observe climatic variation in different zones.

Flora and Fauna
The basin has varied vegetation due to varied topography. In plains, one can see deciduous trees such as teak, sal and peepal. In the hilly region, one can see coniferous trees such as pine, chir and deodar, and in Sunderban, one can see mangrove trees such as Sundari.

It has a great variety of fauna. Elephants, tigers, deer and monkeys are common here. The Brahmaputra plain is known one-horned rhinoceros and Sunderbans is known for Bengal Tigers, crocodile and alligators. Rohu, Katla and Hilsa are some of the prominent fish varieties of this region.

Ganga is home to Susu or Gangetic River Dolphins. These are blind dolphins and rely on echolocation for navigation. The species is under threat due to the pollution caused by mindless dumping of untreated sewage water and chemicals.

The Ganga and the Brahmaputra plains are the most populated regions of the basin. The hilly region has very less population. Most of the workforce is engaged in agriculture and allied sectors. Paddy is the main crop here. Wheat, maize, sorghum, gram and millet are other major crops of this region. Cash crops such as sugarcane and jute are also grown here. Tea plantation is a common site in West Bengal and Northeast India. Sericulture or Silk Farming is also practised here in the Indian state of Bihar, West Bengal and Assam.

The Ganga-Brahmaputra Basin is home to several major cities of India such as Delhi, Dehradun, Haridwar, Allahabad, Kanpur, Varanasi, Lucknow, Patna and Kolkata. It has a population of more than 500 million, making most populated river basin in the world.

All four forms of transport are well developed in the basin. Kolkata is an important inland port on River Hooghly.

Tourism plays an important role in the economic development of the area. Some of the prominent tourist sites in the Ganga-Brahmaputra basin are Tajmahal (Agra), Sangam (Allahabad), Buddhist Stupas (Uttar Pradesh and Bihar), Kaziranga National Park (Assam) and Manas National Park (Assam).

Ganga-Brahmaputra River Basin Map
Ganga-Brahmaputra Basin
Source: NCERT