1.3. Distribution of the continents and oceans

Key Concept:

Continents and oceans are unevenly distributed on Earth’s surface due to the movement of tectonic plates over millions of years.

Short Notes:

Today’s continents are not randomly placed; their positions are the result of long-term plate movement. Initially joined as Pangaea, the landmasses drifted apart, forming the Atlantic, Indian, and Pacific Oceans between them.

Currently, seven continents (Africa, Antarctica, Asia, Australia, Europe, North America, and South America) and five oceans (Atlantic, Indian, Pacific, Arctic, and Southern) define Earth’s surface. Their distribution is the outcome of millions of years of movement, collision, and separation of Earth’s lithospheric plates.

Africa, for example, was once part of Gondwanaland, and as the supercontinent broke apart, the Indian Ocean formed between Africa and Asia. These changes have major effects on climate, biodiversity, and human development.

Key Terms:

• Continents – Large continuous landmasses on Earth,
• Oceans – Major bodies of salt water,
• Pangaea – Supercontinent that broke into current continents,
• Lithospheric Plates – Rigid outer shell of Earth that moves,
• Tectonic Movement – Shifting of Earth’s plates that forms continents and oceans.

Example:

The separation of South America from Africa created the Atlantic Ocean, whose shape and width continue to change.