Underwater life | Year 2 English (Cambridge) PDF Download

Introduction to Oceans

An ocean is a huge body of salt water. Oceans cover nearly 71 percent of Earth's surface and contain almost 98 percent of all the water on Earth.

The Five Main Oceans

There are five main oceans in the world:

• The Pacific Ocean
• The Atlantic Ocean
• The Indian Ocean
• The Arctic Ocean
• The Southern Ocean

These oceans are all connected, forming one large body of water. This is why they are sometimes called the world ocean.

Parts of the Oceans

Different parts of the oceans have different names:

• Seas: Smaller parts of the ocean partly enclosed by land (e.g., the Caribbean Sea).
• Gulfs: Large areas of the sea partly enclosed by land (e.g., the Gulf of Mexico).
• Bays: Broad inlets of the sea where the land curves inward (e.g., the Bay of Bengal).

Salty Water

• Ocean water is salty because it contains a substance called sodium chloride. 
• This salt is dissolved in the water, making it salty to taste.

Ocean Currents

Ocean water is always moving. Large amounts of water move in patterns called currents.
Currents can be:

• Warm Currents: They bring warm weather and rain to nearby lands.
• Cold Currents: They usually cause dry climates.

Waves and Winds

• Waves: Winds cause waves on the ocean’s surface. Strong winds make big waves, while gentle breezes create small ripples.

Ocean Floor

The ocean floor has different levels:

• Continental Shelf: The shallowest part, close to land.
• Ocean Basins: The deep parts of the ocean.
• Trenches: Deep cracks in the ocean floor.
• Ocean Ridges: Underwater mountain chains rising from the ocean floor.

Life in the Ocean

Plants and animals live at all levels of the ocean:

• Plants: Most ocean plants grow near the surface where there is sunlight. Common ocean plants include phytoplankton (tiny one-celled plants), seagrass, and seaweed.
• Animals: Many ocean animals live in shallow waters, but some live in deep water. Examples include:
  • Blue Whale: The largest animal in the ocean.
  • Zooplankton: Tiny animals drifting with the currents.
  • Other Animals: Clams, crabs, squid, dolphins, and many kinds of fish.

Interesting Facts

• Blue Whale: The blue whale is the largest animal ever to live on Earth.
• Corals: Corals look like plants but are actually animals.

Conclusion

Oceans are a vital part of our planet, covering most of Earth's surface and home to countless plants and animals. They are always in motion, with currents and waves shaping their behavior and impacting the climate. Oceans are fascinating and full of life at every level, from the tiniest plankton to the largest whales.