Lecture Notes: Earth and Its Landforms

Pangea and Continental Drift

• Pangea: Supercontinent existing 240 million years ago, surrounded by the ocean Pantalasa.
• Continental Drift: Theory by Alfred Wiegener (1912) explaining the movement of continents from Pangea to current positions.
  • Fossil evidence (e.g., Mesosaurus) and matching geological formations across continents.
  • Initially lacked a mechanism, later explained by plate tectonics.

Plate Tectonics

• Earth's structure: Core, mantle, crust (tectonic plates).
• Tectonic Plates: Crust pieces moving at ~10 cm/year, forming Earth's surface and features.
• Movement Types:
  • Convergent Boundaries: Plates collide, forming mountains.
  • Divergent Boundaries: Plates move apart, forming rifts.
  • Transform Boundaries: Plates slide past, causing earthquakes.
• Impact: Formation of mountains, islands, and potential for new continents.

The Seven Continents

• Asia: Largest continent, home to most of the world's population, Himalayas.
• Africa: 54 countries, Nile River, Sahara Desert, diverse wildlife.
• Europe: 51 countries, diverse cultures, small and large countries.
• North America: 23 countries, natural wonders like the Grand Canyon.
• South America: Bordered by oceans, Amazon rainforest, Andes mountains.
• Australia: Continent and country, Great Barrier Reef.
• Antarctica: Fifth largest, extreme cold, scientific research hub.

Earth's Landforms

• Mountains: Formed by tectonic forces, categorized into fold, block, and volcanic.
• Plains: Flat, fertile areas, suitable for human habitation and agriculture.
• Plateaus: Elevated flatlands, exist globally, formed by tectonic activity or volcanic eruptions.
• Deserts: Dry regions with minimal vegetation, process of desertification.

Earth's Major Domains

• Lithosphere: Earth's crust and upper mantle.
• Hydrosphere: All water bodies; essential for life.
• Atmosphere: Layers of gases surrounding Earth, vital for climate and weather.
• Biosphere: Zone of life, including both plant and animal kingdoms.

Glaciers

• Types: Alpine (mountain) glaciers, and ice sheets.
• Formation: Accumulation and compression of snow over time.
• Role: Store freshwater, indicators of climate change.

Tundra Regions

• Types: Alpine and Arctic.
• Characteristics: Cold, treeless plains, permafrost.
• Adaptations: Flora and fauna adapted to extreme conditions.

Additional Trivia

• Himalayan growth due to tectonic activity.
• Earth's age estimated at 3.7 billion years.
• Antarctic Lambert's Glacier is the largest glacier.
• Tundra's unique adaptations for survival in cold climates.