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

The Earth sustains over seven billion individuals, all interconnected within the intricate ecosystem. Our fundamental necessities—food, clothing, and shelter—are universally shared, underscoring our commonality despite diverse appearances, traits, and cultures. Hence, studying human-environment dynamics in the Tropical and Subtropical Regions is crucial for understanding wildlife, demographics, and other facets of these areas.

Life in the Amazon Basin

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

Amazon Basin in South America

• 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-tolerant vegetation such as orchids and bromeliads can grow in this dark and damp environment.
• The rainforest is abundant in fauna, including birds like toucans, hummingbirds, and macaws with brilliantly colored plumage and oversized bills.
• Animals such as monkeys, sloths, and ant-eating tapirs inhabit the region.
• The jungles are home to various reptiles and snakes, including crocodiles, snakes, pythons, 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 tend to 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 significantly influences population distribution in the basin.
• Mountain areas with steep slopes have inhospitable terrain and lower population density.
• The plains offer fertile land suitable for agriculture, with rice (paddy) being the main crop.
• Other crops grown include wheat, maize, sorghum, gram, millets, sugarcane, and jute.
• Tea plantations are common in West Bengal and Assam, while silk is produced in parts of Bihar and Assam.
  

Vegetation and Wildlife

• The vegetation cover varies based on landforms. Tropical deciduous trees, bamboo groves, and mangrove forests are common.
• Coniferous trees like pine, deodar, and fir are found in cooler regions with steep slopes.
• Wildlife in the basin includes elephants, tigers, deer, monkeys, rhinoceros, Bengal tigers, crocodiles, and various fish species.
  

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

• Roadways, railways, waterways, and air transport are well-developed in the basin.
• Kolkata serves as an important port on the River Hooghly.
• Tourism highlights include Taj Mahal, Allahabad, Buddhist stupas, Lucknow, Assam's wild sanctuaries, and Arunachal Pradesh's tribal culture.