Life in the Tropical and the Subtropical Regions Chapter Notes | Window on the Word Class 7: Solutions, Notes & Worksheets PDF Download

 The connection between humans and their surroundings shapes distinct environments in each region, influencing aspects like lifestyle, clothing, food, occupation, and culture. We have previously studied the various climatic zones across the globe.  In the forthcoming chapters, we will delve into the lives of individuals residing in these regions.  This chapter will focus on two specific locations situated in tropical and subtropical regions: the Amazon basin and the Ganga-Brahmaputra basin.

Life in the Amazon Basin

The Amazon basin is located in northern South America within the tropical region, situated between latitudes 10°N and 10°S. This vast area is drained by the Amazon River, the largest river globally, along with its tributaries. Originating from the Andes Mountains in the west, the Amazon flows eastward, emptying into the Atlantic Ocean. It traverses countries including Peru, Bolivia, Venezuela, Colombia, Ecuador, and Brazil.

Climate

• Due to its equatorial location, the Amazon basin experiences a hot and humid climate all year round. Rainfall is a common occurrence, nearly daily.

Natural Vegetation

• The Amazon basin is predominantly covered by the dense Amazon rainforest, housing a myriad of plant species. This rainforest is characterized by tall broadleaf hardwood trees that create a dense canopy, limiting sunlight penetration to the forest floor. Consequently, the lower levels of the forest remain dark and moist, inhibiting significant undergrowth. This unique ecosystem is often referred to as the selva.

Amazon Rainforest

• The rainforest is home to various animals.
• Mammals like jaguars, pumas, armadillos, monkeys, and reptiles such as crocodiles, alligators, and anacondas can be found.
• Birds like scarlet macaws, toucans, and hummingbirds also live in this region.
• Species of freshwater fish, including piranhas and arapaimas, inhabit the Amazon River.

People

• The Amazon basin has a low population density.
• Most inhabitants live in cities along the Amazon River and its tributaries.
• Indigenous groups like the Yanomami and Tikuna have resided in the rainforest for millennia.
• Due to deforestation, diseases, and migration to urban areas, the indigenous population has significantly decreased.

Rainforest Indigenous Groups

• Traditional Lifestyles: Indigenous groups in the rainforest continue their traditional ways of living, adapted to the forest environment. Some groups are settled in various parts of the basin, while others are nomadic.
• Housing: The people typically reside in traditional huts constructed from natural materials found in the forest. These huts are temporary and require periodic rebuilding. Some groups live in communal houses known as malocas, which have sloped roofs.
• Occupations: The main activities of these indigenous groups include hunting, food gathering, fishing, and various forms of agriculture. Slash and burn agriculture is a common practice among them.

Slash Burn Agriculture

• Slash and burn agriculture, also referred to as shifting agriculture, involves clearing a portion of forest by burning trees and using the resulting ash to enhance the soil.
• When the soil's fertility decreases over time, individuals relocate to a new area.
• The primary food crops cultivated include vegetables such as plantain, pineapples, sweet potato, and cassava.
• Major cash crops grown are cocoa, coffee, soya bean, and rubber.

Impact of Human Interaction on the Amazon Rainforest

Impact of Human Interaction on the Region

• The Amazon rainforest's interiors were mostly unreachable until the 1970s when the Trans-Amazonian highway was constructed, granting access to outsiders. This event led to extensive deforestation for various purposes like logging, farming, mining, and settlement. The consequences include damage to the forest's ecosystems and the displacement of indigenous communities.

Environmental Significance of the Amazon Rainforest

• The Amazon rainforest acts as the largest carbon sink globally, absorbing carbon dioxide and releasing oxygen, thereby playing a crucial role in regulating the Earth's climate. Deforestation in the region has disrupted this balance, contributing to global warming, soil degradation, and land infertility.

Life In The Ganga-Brahmaputra Basin  

• The Ganga-Brahmaputra basin is located in the subtropical region.
• It spans from 10°N to 30°N latitudes.
• The rivers Ganga and Brahmaputra, along with their tributaries, create a vast river basin in northern India.
• The Ganga originates from the Gangotri glacier in the Himalayas. Its main tributaries include Yamuna, Ghaghra, Son, Gandak, and Kosi.
• The Brahmaputra starts as the Yarlung Tsangpo from the Angsi Glacier in Tibet. It flows eastwards through Arunachal Pradesh, Assam, and Bangladesh, where it merges with the Ganga and empties into the Bay of Bengal, forming the Sundarbans Delta, the largest delta globally.
• Most of Bangladesh is situated within this delta.

Climate and Natural Vegetation

• Summers are hot, and winters are cold in this region.
• The South-West Monsoon Winds bring plentiful rainfall to the area from June to September.

Geography of the Region

Vegetation:

• The people in this area have been clearing forests for farming for many centuries, leading to a scarcity of natural vegetation. However, the Sundarbans in the delta region stands as the world's largest mangrove forest, known for thriving in both fresh and salty water.
• In mountainous and foothill areas, you can find tropical evergreen forests, deciduous forests, and coniferous trees like pine, cedar, deodar, and fir in places like Uttarakhand and Arunachal Pradesh. Assam boasts thick bamboo forests.

Wildlife:

• Notable animals in the region include elephants, Bengal tigers, deer, monkeys, one-horned rhinoceroses, crocodiles, and diverse freshwater fish such as catla, hilsa, and rohu.

People:

• The population distribution is influenced by the terrain, with the Himalayan mountain areas sparsely populated while the plains are densely inhabited.
• Agriculture is the primary occupation in the plains, with paddy (rice) being the main crop due to its need for ample water.
• Other crops include wheat, sugarcane, jute, pulses, and vegetables, with tea cultivation prominent in Assam and West Bengal.
• Farmers in the plains practice subsistence and intensive farming, using traditional methods like manure, irrigation, and quality seeds to enhance soil productivity.
• Indigenous communities in hilly areas practice shifting agriculture, known as Jhum in northeast India.

Occupations:

• Fishing and sericulture (silkworm cultivation) are significant activities in the region.
• Notable cities in the Ganga basin include Allahabad.

Ganga-Brahmaputra Plain

we explore why the Ganga-Brahmaputra Plain stands out as one of the most densely populated regions globally.

Factors Contributing to High Population Density

• The fertile soil in the region, courtesy of the Ganga and Brahmaputra rivers, supports robust agricultural practices.
• The flat terrain facilitates a well-connected network of transportation, including roads, railways, and navigable river routes.
• The region enjoys a favorable climate for agriculture, fostering economic growth.
• Diverse industries, both agriculture-based and mineral-based, have emerged, offering ample employment opportunities to the population.

Key Cities and Cultural Significance

The Ganga-Brahmaputra Plain is home to vibrant cities like Varanasi, Kanpur, Lucknow, Patna, and Kolkata, each rich in historical, cultural, and religious heritage.

Tourism and Economic Activity

Given the historical and cultural significance of the region, tourism plays a vital role in the economic landscape of the Ganga-Brahmaputra Plain.

Impact of Human Interaction on the Region

Ganga-Brahmaputra Region: This area has been a hub of human activity for many years. However, it faces challenges such as overpopulation and environmental harm.

Environmental Degradation: Waste from towns and industries is regularly dumped into the rivers, causing pollution.

Deforestation: As the population increases, forests are cleared for new settlements, leading to a decline in natural resources.

Global Warming and Sea Level Rise: The Sundarbans delta, in particular, is at risk due to global warming. A slight increase in sea levels could result in vast areas of the basin being flooded, impacting the livelihoods of numerous farmers and fisherfolk.