Social Science 2 : 🏔 Chapter 01: On the Roof of the World

📘 Title: On the Roof of the World

Chapter: 1
Subject: Social Science II – Geography
Grade: 9 (Kerala Syllabus)

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🔍 Summary (150–250 words)

The chapter "On the Roof of the World" provides an in-depth exploration of the Northern Mountain Region of India, focusing on its formation, features, and influence on human life. It begins by introducing the Himalayan mountain system, formed due to the collision between the Indian and Eurasian tectonic plates. This vast region includes Trans Himalayas, The Himalayas, and Eastern Hills, each with unique geographic and ecological characteristics.

The Himalayas are subdivided into Himadri (Greater Himalayas), Himachal (Lesser Himalayas), and Shiwaliks (Outer Himalayas). Key features such as gorges, glaciers, passes, and valleys are explained. The region is further divided regionally into Western, Central, and Eastern Himalayas, with prominent peaks like K2, Kanchenjunga, and Nanda Devi, and rivers such as Indus, Ganga, and Brahmaputra.

It covers natural features (soil, vegetation, wildlife), human adaptations like terrace farming, transhumance, and economic activities such as tourism, agriculture, and animal husbandry. The region's monsoon climate, strategic passes, and abundant natural resources make it vital for India's cultural and ecological balance.

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📌 Capsule Notes

🏔️ Physiographic Divisions:

• Trans Himalayas: Includes Karakoram, Zaskar, and Ladakh ranges.

• Himalayas Proper: Three parallel ranges—Himadri, Himachal, and Shiwalik.

• Eastern Hills (Purvachal): Includes Naga, Mizo, Patkai hills.

🧭 Formation:

• Result of convergent plate movement (Indian Plate & Eurasian Plate).

• Fold mountains formed from sedimentary rock compression (Tethys Sea uplift).

🌍 Regional Divisions:

• Western Himalayas (Jammu & Kashmir, Himachal Pradesh, Uttarakhand)

  • Notable Peaks: K2 (8611 m), Nanda Devi.

  • Glaciers: Siachen, Gangotri, Yamunotri.

  • Passes: Banihal, Rohtang, Baralacha La.

• Central Himalayas (Nepal, Sikkim)

  • Mount Everest, Kanchenjunga, Nathula Pass.

  • Darjeeling Tea and terrace farming.

• Eastern Himalayas (Assam, Arunachal Pradesh)

  • Namcha Barwa, Brahmaputra Valley, Root Bridges.

  • Purvachal Hills and rain-rich climate.

🌦️ Climate:

• Varies with altitude: mild in Shiwaliks, polar-like in Ladakh.

• Monsoon rains on southern slopes; heavy rain in northeast (Meghalaya).

🏞️ Drainage System:

• Perennial Rivers: Indus, Ganga, Brahmaputra and tributaries.

• Features: gorges, V-shaped valleys, waterfalls.

🌱 Soil & Vegetation:

• Mountain & forest soils; Karewas in Kashmir support saffron.

• Vegetation zones: tropical to alpine; conifers at mid-altitudes.

🐾 Wildlife:

• Home to yak, musk deer, snow leopard, and rhinoceros.

• Protected via national parks and biosphere reserves.

🌾 Agriculture & Livelihood:

• Terrace farming, shifting cultivation, and pastoralism.

• Bugyals: summer meadows for grazing (transhumance).

🏞️ Tourism:

• Adventure (skiing, trekking), pilgrimage (Amarnath, Manasarovar), resorts (Shimla, Darjeeling).

• Three stages: Pilgrimage → Colonial → Adventure tourism.

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❓ Q&A – Questions with Answers

1. What are the three major divisions of the Northern Mountains?
   → Trans Himalayas, Himalayas, and Eastern Hills.

2. How was the Himalayas formed?
   → By the collision of the Indian and Eurasian tectonic plates at a convergent boundary.

3. What is the significance of the Karewas soil?
   → Rich in humus, ideal for saffron cultivation in Kashmir Valley.

4. Name any two important glaciers of the Western Himalayas.
   → Siachen Glacier, Gangotri Glacier.

5. Why are the Himalayan rivers water-rich throughout the year?
   → Because they are both rain-fed and snow-fed (perennial).

6. What is transhumance?
   → Seasonal migration of shepherds with livestock between valleys and meadows.

7. Mention two features of Himadri.
   → Highest and innermost range of the Himalayas; includes peaks like Mount Everest.

8. Which is the highest battlefield in the world?
   → Siachen Glacier.

9. Why are there numerous hill stations in the Himalayas?
   → Pleasant climate, scenic beauty, and colonial legacy.

10. List any two rivers that originate from the Himalayas.
    → Ganga (from Gangotri Glacier), Brahmaputra (from Chemayungdung Glacier).

11. What kind of vegetation is found at higher altitudes?
    → Alpine meadows and tundra-like vegetation.

12. What is the role of passes in the Himalayas?
    → Enable transport and trade across mountains (e.g., Nathula, Rohtang).

13. Name two national parks located in the Himalayan region.
    → Valley of Flowers (Uttarakhand), Kaziranga (Assam).

14. Explain the term ‘Bugyals’.
    → Alpine pastures between 3000–4500m used for grazing during summer.

15. Why is the Eastern Himalayas rain-rich?
    → Due to monsoon winds getting trapped between Assam Himalayas and Purvachal.

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📚 Definitions & Key Terms

• Trans Himalayas: Northernmost ranges including Karakoram, Ladakh, and Zaskar.

• Fold Mountains: Mountains formed due to compression and folding of rock strata.

• Gorge: Deep valley with steep sides formed by river erosion.

• Bugyals: High-altitude alpine meadows.

• Transhumance: Seasonal migration of pastoralists.

• Karewas: Glacial alluvial deposits in Kashmir Valley.

• Biosphere Reserve: Protected areas for conservation of biodiversity.

• Pass: Natural gap or route through a mountain range.

• Tundra: Treeless region found at high altitudes with cold climates.

• Alluvial Soil: Fertile soil deposited by rivers; found in valleys.

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🧠 Main Points for Revision

• Trans Himalayas = Tibetan Himalayas.

• Himalayas = Himadri (inner), Himachal (middle), Shiwalik (outer).

• Formation = Indian Plate collided with Eurasian Plate.

• K2 = 2nd highest peak, in Karakoram.

• Bugyals = Seasonal pastures.

• Karewas = Ideal for saffron in Kashmir.

• Himalayan rivers = Perennial.

• Passes = Rohtang, Nathula, Banihal.

• National parks = Kaziranga, Corbett, Valley of Flowers.

• Tourism = Religious, colonial, and adventure types.

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📂 Topic-Wise Breakdown

I. Introduction

• Cultural & geographical diversity.

• Physiographic zones listed.

II. Northern Mountains Overview

• Origin from Pamir Knot.

• 2400 km long, 150–400 km wide.

III. Major Subdivisions

1. Trans Himalayas

2. Himalayas

   • Himadri

   • Himachal

   • Shiwalik

3. Eastern Hills (Purvachal)

IV. Regional Himalayas

• Western Himalayas: J&K, Himachal, Uttarakhand.

• Central Himalayas: Sikkim, Darjeeling (Nepal-dominant).

• Eastern Himalayas: Assam, Arunachal.

V. Climate & Natural Features

• Monsoon effects.

• Gorges, V-shaped valleys, waterfalls.

VI. Natural Resources

• Soils: Karewas, mountain soil.

• Vegetation: tropical to alpine.

• Wildlife: diverse and protected.

VII. Human Life

• Agriculture: terraced, shifting, tea.

• Transhumance & animal husbandry.

• Tourism: pilgrimage, resorts, adventure.