Year 2 Science

Under the Sea: The Ocean Habitat

ocean habitat

Let's have a look beneath the surface of the ocean. Put on your scuba-diving gear. Is your mask on tight? Are the air tanks full? Okay, let's jump in!

Look at the ground under the water. The sandy beach continues to slope down. We call the bottom of the sea the sea bed. Where the sea is shallow, the sea bed is close to the water's surface. Sometimes the seabed rises out of the water, and that makes an island. Where the wider ocean is deep, the ocean floor drops a long way down. Long, deep valleys run across it. The deepest valleys are called ocean trenches. You can think of the ocean floor as a landscape of mountains, valleys and trenches, stretching out for thousands of miles underwater.

So many different animals live in the sea. Can you name some? Did you think of fish, sharks, dolphins and others? Did you know that if you scoop up a handful of sea water, you're holding many living creatures? These creatures are so tiny that you can't see them. It would seem as if you were holding just a handful of water, but really the water is full of little living things!

There's a special name for all these teeny-tiny animals, along with many teeny-tiny plants, that drift in the sea: they're called plankton. The sea is home not only to teenytiny plankton but also to some of the world's largest creatures. Can you name any of these big oceangoing creatures? Did you think of whales?

The Blue Whale, the biggest whale of all, can grow to 30 metres long and weigh almost 180,000 kilograms. It's hard to imagine how big that is! If about thirty children your size were to lie down in a line, head to toe, they might add up to the length of a blue whale. But to add up to the weight of a blue whale, it would take about seven thousand children your size!

There's a food chain for animals and plants in the sea, just as there is for animals and plants on land. One ocean food chain is amazing: some whales eat only plankton. Think about it: some of the biggest ocean animals eat only some of the smallest plants and animals! How would you like to have the same thing every day for breakfast, lunch, dinner and snacks, and never see what you're swallowing?

The sea helps the world's people. It has many different habitats for many different plants and animals. It helps the planet earth stay healthy. That's why people have to be careful not to do things to harm the sea.

This activity is adapted from pages 299 - 301 of What Your Year 2 Child Needs to Know, which can be purchased here.

Click below to see the related activity.

science owl