Class 7 Geography Notes - Human Environment Interactions : The Tropical and Sub Tropical Region

The Earth supports more than seven billion people, all connected through a complex ecosystem. Everyone shares basic needs like food, clothing, and shelter, showing how similar we are despite our different looks, characteristics, and cultures. This makes it important to study how humans and the environment interact in the Tropical and Subtropical Regions to better understand the wildlife, population, and other features of these areas.

Amazon Basin in South America

Life in the Amazon Basin

Life in the Amazon Basin is a captivating topic that showcases the complex bond between the environment and its people. The Amazon Basin lies directly on the equator, experiencing a hot and humid climate year-round. Both day and night are nearly equally warm, making the skin feel sticky due to the high humidity. It rains almost daily, often unexpectedly. Although daytime temperatures are high, they drop slightly at night, while humidity remains high.

The Amazon basin is located close to the equator, between 10° N and 10° S, known as the equatorial region.

The river Amazon flows from west to east, from the mountains to the Atlantic Ocean.

• The point where a river meets another body of water is called the river's mouth.
• Multiple tributaries combine to form the Amazon River and its basin.
• The Amazon basin drains parts of Brazil, Peru, Bolivia, Ecuador, Colombia, and a small part of Venezuela.

The Climate in the Amazon Basin

The Amazon Basin is located directly on the equator. It features a hot and wet climate all year round.

• Both day and night are consistently hot and humid.
• The skin often feels sticky due to the humidity.
• Rain is a common occurrence almost every day, usually without much warning.
• Daytime temperatures are high, accompanied by very high humidity levels.
• During the night, temperatures decrease, but humidity levels remain high.

Rainforests

Given the consistent rainfall throughout the year, it's unsurprising that the Amazon Basin boasts a diverse array of trees, collectively referred to as the rainforest. This abundance of rainfall is the primary factor driving the growth of these forests. Additionally, the rainforests provide a natural habitat for numerous tropical birds and animals.

Rainforest

• Thick forests grow due to heavy rainfall, creating a dense roof that blocks sunlight from reaching the ground.
• Only shade-loving plants like orchids and bromeliads can survive in this dark and moist setting.
• The rainforest is home to a wide range of animals. Birds such as toucans, hummingbirds, and macaws are common, known for their bright colours and large beaks, and they often make loud sounds.
• Animals like monkeys, sloths, and tapirs live in the area.
• Many species of reptiles and snakes thrive here, including crocodiles, anacondas, and boa constrictors.
• The basin supports thousands of species of insects and several species of fish, including the flesh-eating Piranha fish.
• The region exhibits an extraordinary diversity of life forms.

People of the Rainforest

People in the rainforests grow most of their food in small cleared areas. Men hunt and fish while women take care of the crops.

Slash and Burn Agriculture

• Main crops grown include tapioca, pineapple, and sweet potato. Women sustain families by feeding them the vegetables they grow.
• They practice "slash and burn agriculture" and primarily consume manioc (cassava) and queen ants and sacs.
• Cash crops such as coffee, maize, and cocoa are also cultivated.
• The rainforests provide wood for housing, with some living in thatched beehive-shaped houses and others in large Maloca houses with steeply slanting roofs.
• Access to the heart of the forest increased with the construction of the Trans-Amazon highway in 1970, alongside the use of aircraft and helicopters.
• Indigenous populations were displaced, leading to changes in farming practices in new areas.
• Development activities are causing the gradual destruction of biologically diverse rainforests, with a significant annual loss in the Amazon basin.
• Forest destruction leads to topsoil erosion, transforming lush forests into barren landscapes.

Life in the Ganga-Brahmaputra Basin

The Ganga-Brahmaputra basin is formed by the tributaries of rivers Ganga and Brahmaputra in the Indian subcontinent.

• The basin lies in the sub-tropical region between 10°N to 30°N latitudes.
• Main tributaries of River Ganga include Ghaghra, Son, Chambal, Gandak, and Kosi.
• The basin includes plains, mountains, foothills of the Himalayas, and the Sundarbans delta.
• Ox-bow lakes are scattered across the plain area.
• The region experiences a monsoon climate with rains from mid-June to mid-September.

Population Distribution and Agriculture

• The environment greatly affects how people are spread out in the basin. 
• Mountainous areas with steep slopes are hard to live in, leading to lower population densities, while the plains are very suitable for habitation, resulting in a high population density.
• The plains have fertile land ideal for farming, with rice (paddy) as the main crop. Paddy needs a lot of water, so it is grown where there is plenty of rain. 
• Other crops include wheat, maize, sorghum, gram, and millets. 
• Cash crops such as sugarcane and jute are also grown, and there are banana plantations in some areas. 
• Tea plantations are common in West Bengal and Assam, while silk is produced in parts of Bihar and Assam.

Vegetation and Wildlife

• The type of vegetation varies with the landforms. 
• Common plants include tropical deciduous trees, bamboo groves, and mangrove forests. 
• In cooler, higher regions, you can find coniferous trees like pine, deodar, and fir.
• Wildlife in the basin includes elephants, tigers, deer, monkeys, rhinoceros, Bengal tigers, crocodiles, and a variety of fish.

Urban Centers and Pollution

• Major cities like Allahabad, Kanpur, Varanasi, Lucknow, Patna, and Kolkata are located along River Ganga.
• Urban wastewater and industrial discharge contribute to river pollution.
  

Transportation and Tourism

• The basin has well-developed roadways, railways, waterways, and air transport. 
• There are many airports in the plain area. 
• Key tourist attractions include the Taj Mahal on the banks of the Yamuna in Agra, Allahabad at the confluence of the Ganga and Yamuna, Buddhist stupas in Uttar Pradesh and Bihar, Lucknow with its Imambara, Kaziranga and Manas wildlife sanctuaries in Assam, and the unique tribal culture of Arunachal Pradesh.