🌏 World Geography – Summary Notes
🟩 1. Introduction to World Geography
- Geography is the study of the Earth’s surface, features, climate, population, and resources.
- It explains the relationship between humans and their environment.
- The Earth is the 3rd planet from the Sun and the 5th largest in the solar system.
🟩 2. The Shape and Structure of the Earth
- Shape: Oblate spheroid (slightly flattened at poles).
- Layers of the Earth:
- Crust – outermost, solid layer (made of rocks and minerals).
- Mantle – thick middle layer of molten rocks (magma).
- Core – innermost, very hot (mainly iron & nickel).
- Continents (7):
Asia, Africa, North America, South America, Europe, Australia, Antarctica.
- Oceans (5):
Pacific, Atlantic, Indian, Southern, Arctic.
🟩 3. Latitudes and Longitudes
- Latitude: Imaginary lines running east–west (e.g., Equator 0°).
- Longitude: Imaginary lines running north–south (e.g., Prime Meridian 0°).
- Equator divides Earth into Northern and Southern Hemispheres.
- Prime Meridian (0° longitude) divides Earth into Eastern and Western Hemispheres.
- Important Latitudes:
- 0° – Equator
- 23½° N – Tropic of Cancer
- 23½° S – Tropic of Capricorn
- 66½° N – Arctic Circle
- 66½° S – Antarctic Circle
🟩 4. Motions of the Earth
| Motion | Description | Effect |
|---|
| Rotation | Earth spins on its axis (24 hrs) | Day & night |
| Revolution | Earth orbits the Sun (365¼ days) | Seasons |
- Tilt of Earth’s Axis: 23½° – causes different seasons.
🟩 5. Landforms of the Earth
Formed by internal (endogenic) and external (exogenic) forces.
🌄 Major Types of Landforms:
| Type | Characteristics | Examples |
|---|
| Mountains | High elevated areas | Himalayas, Andes, Rockies |
| Plateaus | Flat-topped highlands | Deccan Plateau, Colorado Plateau |
| Plains | Low flat lands, fertile | Indo-Gangetic Plain, Great Plains (USA) |
| Deserts | Dry, sandy, little rainfall | Sahara, Thar, Gobi |
| Islands | Land surrounded by water | Greenland, Sri Lanka |
| Peninsulas | Land surrounded by water on 3 sides | India, Arabia |
🟩 6. Continents Overview
🌍 Asia
- Largest continent (≈30% of land area).
- Bounded by Arctic (N), Pacific (E), Indian Ocean (S).
- Major countries: China, India, Japan.
- Highest point: Mount Everest (8,848 m).
🌍 Africa
- 2nd largest continent.
- Crossed by Equator, Tropic of Cancer, and Tropic of Capricorn.
- Longest river: Nile River.
- Largest desert: Sahara Desert.
🌍 North America
- 3rd largest continent.
- Bordered by Arctic (N), Atlantic (E), Pacific (W).
- Important features: Rocky Mountains, Mississippi River, Great Lakes.
🌍 South America
- Famous for Andes Mountains, Amazon River (world’s largest by volume), Amazon Rainforest.
- Mostly tropical climate.
🌍 Europe
- 2nd smallest continent, but highly developed.
- Divided from Asia by Ural Mountains.
- Major rivers: Danube, Rhine.
🌍 Australia
- Smallest continent, island continent.
- Mostly desert and grassland.
- Important features: Great Barrier Reef, Great Dividing Range.
🌍 Antarctica
- Covered with ice, coldest continent.
- No permanent human settlement.
🟩 7. Oceans of the World
| Ocean | Features |
|---|
| Pacific | Largest and deepest ocean (Mariana Trench) |
| Atlantic | Second largest, important for trade routes |
| Indian | Warm ocean, borders Asia, Africa, Australia |
| Southern | Surrounds Antarctica |
| Arctic | Smallest and shallowest, around North Pole |
🟩 8. Major River Systems
| Continent | Major Rivers |
|---|
| Asia | Ganga, Yangtze, Indus, Mekong |
| Africa | Nile, Congo, Niger |
| Europe | Volga, Danube, Rhine |
| North America | Mississippi, Missouri, St. Lawrence |
| South America | Amazon, Orinoco |
| Australia | Murray–Darling |
🟩 9. Climate Zones of the World
Based on latitude and temperature:
| Zone | Latitude Range | Climate |
|---|
| Tropical Zone | Between 23½° N & 23½° S | Hot & humid (e.g., Amazon, Congo) |
| Temperate Zone | 23½°–66½° (N & S) | Moderate (e.g., Europe, N. America) |
| Frigid Zone | Beyond 66½° (N & S) | Very cold (e.g., Arctic, Antarctica) |
🟩 10. Natural Vegetation
| Type | Region | Example |
|---|
| Tropical Rainforest | Equatorial regions | Mahogany, Ebony |
| Tropical Grasslands | Africa, South America | Savanna, Llanos |
| Temperate Forests | Europe, North America | Oak, Maple |
| Desert Vegetation | Sahara, Arabia | Cactus |
| Tundra | Polar regions | Moss, Lichen |
🟩 11. Major Natural Resources
| Resource | Major Producers |
|---|
| Coal | China, USA, India |
| Petroleum | Saudi Arabia, Russia, USA |
| Iron Ore | Brazil, Australia, India |
| Gold | South Africa, Australia |
| Natural Gas | Russia, Iran, Qatar |
🟩 12. Population and Human Geography
- World population: ~8 billion (2025).
- Most populated continents: Asia, Africa.
- Least populated: Antarctica, Australia.
- Major languages: English, Chinese, Spanish, Hindi, Arabic.
- Urbanization: Increasing rapidly, especially in Asia & Africa.
🟩 13. Major Geographical Phenomena
| Phenomenon | Cause / Example |
|---|
| Volcanoes | Movement of tectonic plates (e.g., Mount Fuji, Vesuvius) |
| Earthquakes | Fault movement between plates |
| Tsunami | Underwater earthquake or volcanic eruption |
| Hurricanes/Cyclones | Intense tropical storms over oceans |
| Glaciers | Slow-moving ice masses in polar regions |
🟩 14. Important Mountain Ranges
| Range | Continent | Highest Peak |
|---|
| Himalayas | Asia | Mt. Everest |
| Andes | South America | Aconcagua |
| Rockies | North America | Mt. Elbert |
| Alps | Europe | Mont Blanc |
| Atlas | Africa | Toubkal |
🟩 15. Important Deserts
| Desert | Continent | Type |
|---|
| Sahara | Africa | Hot |
| Gobi | Asia | Cold |
| Kalahari | Africa | Hot |
| Arabian | Asia | Hot |
| Atacama | South America | Dry (driest place on Earth) |
| Great Victoria | Australia | Hot |
🟩 16. Major Islands and Peninsulas
| Island | Location |
|---|
| Greenland | North America (largest island) |
| Madagascar | Africa |
| Borneo | Asia |
| New Guinea | Pacific |
| Japan | Asia |
| British Isles | Europe |
| Peninsula | Location |
|---|
| Arabian Peninsula | Asia |
| Indian Peninsula | Asia |
| Iberian Peninsula | Europe |
| Scandinavian Peninsula | Europe |
| Yucatán Peninsula | North America |
🟩 17. Environmental Issues
- Deforestation → loss of biodiversity.
- Global Warming → rising temperatures, melting glaciers.
- Desertification → expansion of deserts.
- Pollution → air, water, soil degradation.
- Ozone Layer Depletion → increased UV radiation.
Global Efforts:
Paris Agreement, UNFCCC, Kyoto Protocol, sustainable development goals (SDGs).
🧭 Quick Recap Chart
| Topic | Key Points |
|---|
| Continents | 7 |
| Oceans | 5 |
| Highest Peak | Mt. Everest |
| Longest River | Nile (Africa) |
| Largest Ocean | Pacific |
| Largest Desert | Sahara |
| Coldest Place | Antarctica |
| Densest Population | Asia |
| Climate Type | Tropical → Polar |
| Main Resources | Coal, Oil, Iron, Water |
