Chapter 7 — Human Environment Interactions

Chapter 7 of the Class 7 Geography NCERT textbook (Our Environment), "Human Environment Interactions", examines life in two major basins — the Amazon Basin in equatorial South America and the Ganga-Brahmaputra Basin in the subtropical Indian subcontinent — showing how climate and landforms shape livelihoods, food, and shelter.

• Comparing two river basins — The chapter contrasts the equatorial Amazon with the subtropical Ganga-Brahmaputra to show how a basin's latitude, climate, and landforms together mould the way people live within it.
• Life in the Amazon rainforest — It describes the hot, wet Amazon's dense canopy and rich wildlife, and how indigenous people practise slash-and-burn farming, grow manioc, and build thatched huts and Maloca houses.
• The fertile Ganga-Brahmaputra plains — It portrays the basin's fertile land supporting paddy, wheat, sugarcane, and jute, its distinctive wildlife like the one-horned rhino and blind dolphin, and its great riverside cities and tourism.
• Development and its pressures — The chapter links human activity to environmental cost — the Trans-Amazon Highway driving deforestation and displacement, and urban-industrial waste polluting the Ganga — highlighting the interaction's downside.

1. 01The Amazon Basin is the largest river basin in the world, in the equatorial region (10°N–10°S), draining parts of Brazil, Peru, Bolivia, Ecuador, Colombia, and a small part of Venezuela.
2. 02Amazon's hot, wet climate produces dense rainforests where the leaf-and-branch canopy blocks sunlight from the ground; notable wildlife includes toucans, macaws, piranha, anacondas, tapirs, and sloth.
3. 03Amazon people practise slash-and-burn agriculture; their staple is manioc (cassava); homes range from thatched beehive-shaped huts to large Maloca houses with steeply slanting roofs.
4. 04The Trans-Amazon Highway (1970) made the rainforest accessible, displaced indigenous communities, and accelerated deforestation; when forest cover is lost, topsoil is washed away by rain.
5. 05The Ganga-Brahmaputra Basin lies in the subtropical region (10°N–30°N); its fertile plains support paddy (main crop), wheat, sugarcane, jute, tea (West Bengal and Assam), and silk (Bihar and Assam).
6. 06Basin vegetation ranges from tropical deciduous trees (teak, sal, peepal) and Sundarbans mangroves in the delta to coniferous forests (pine, deodar, fir) in the Himalayan foothills of Uttarakhand, Sikkim, and Arunachal Pradesh.
7. 07Unique wildlife includes the one-horned rhinoceros in the Brahmaputra plain, Bengal tiger and crocodiles in the delta, and the blind dolphin Susu — whose presence indicates river health — in the Ganga and Brahmaputra.
8. 08Six cities with populations above ten lakhs lie along the Ganga — Allahabad, Kanpur, Varanasi, Lucknow, Patna, and Kolkata; industrial and urban wastewater discharged into the rivers causes serious pollution.