Destination Biology for Kids: The Ocean Food Chain
Just as we have a food chain on land, there is also a food chain that thrives within the ocean. Food chains are important because they help to maintain the balance and populations of all living species in the environment. Although there are thousands of different types of creatures that live in the ocean, we classify them into four main groups in the food chain: large creatures, meat eaters, plant eaters and plants. Read on to learn about the exciting and amazing underwater world!
Level 4: Large Creatures
At the top of the food chain are the largest and most powerful creatures. They include fish as well as mammals (warm-blooded animals). Another word used to describe the creatures at Level 4 is Predators. A predator is a creature that survives by eating other (usually smaller) fish or animals. There are three main categories of predators at this level. The first are the ones that always live in the ocean: sharks, whales, dolphins and large tuna. The second category includes mammals who spend some of their time in water and some time on land, such as seals, sea lions and walruses. Finally birds make up the last category. Seabirds such as seagulls, penguins, cormorants and pelicans love to dive into the water to scoop out a fish for their food! Two of the characteristics that allow all of these creatures to be at the top of the food chain are that they are usually larger than the fish they prey on and they are fast at catching them too.
Level 3: Meat Eaters
At Level 3, we find many mid-sized creatures that eat smaller living things. Many of the creatures within this level are fish such as herring, snappers and sardines, as well as cephalopods, like octopuses and squid. The fish usually feed on smaller fish, while the octopuses and squid enjoy creatures such as crabs, shrimp, lobster and small fish for their food.
Level 2: Plant Eaters
The small creatures found at Level 2 mostly enjoy eating various types of plants and plant matter that grow in the ocean. You might think that slimy seaweed is gross, but it is actually an important source of food for many of the little animals at Level 2. There are roughly two very different groups of creatures that can be found here. The first are the larger creatures, such as turtles, sea cows (also known as manatees), and parrotfish among others. The second category contains smaller creatures like jellyfish, sea urchins, krill, mollusks and even some baby fish. Even though some of these creatures can be quite small, they love to eat a lot of plant matter!
Level 1: Plants and simple organisms
Life on land would be in grave danger if we didn’t have any plants or trees, and it is very similar underwater as well. Thousands of different types of plants survive in the ocean and help balance the ecosystem. Apart from the plants, there is another somewhat mysterious little organism. It’s called phytoplankton and in fact it’s only made up of one cell! We might think that such tiny creatures don’t matter at all, but in fact phytoplankton are one of the most important things in the ocean. They convert energy from the sun into nutritious materials. Without phytoplankton, most of the inhabitants in Level 2 would go very hungry. If they started to suffer and die, it would affect the animals in Level 3 in a similar way, and then Level 4!
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| Characteristics | Examples |
| Level 4 | Large creatures that are usually must faster and more powerful than the inhabitants on lower levels. | Sharks, dolphins, whales, tuna, seals, walruses, pelicans, seagulls, penguins. |
| Level 3 | Somewhat large creatures that like to eat meat. | Herring, snappers, sardines, octopuses, squid. |
| Level 2 | Small creatures that eat plants and phytoplankton. | Turtles, sea cows, parrotfish, jellyfish, sea urchins, krill, mollusks. |
| Level 1 | Plants and simple-celled organisms. | Seaweed, algae, phytoplankton. |
Keep in mind that not all creatures fit perfectly into these four levels of the ocean food chain. As an example, here’s a brainteaser for you. Whale sharks, which are technically classified as sharks even though they grow as large as some whales, do not eat large fish like other sharks. Instead they much prefer eating plant parts, plankton, and very tiny fish. Which level do you think the whale shark might belong to?
Learn More About the Ocean Food Chain
- Grow Your Own Shrimp!
- Read More About the Ocean And Its Creatures
- What Happens if a Species is Missing From the Food Chain?
- Watch a Video About the Ocean Food Chain
- Take the Ocean Creatures Quiz
- Meet the Creatures That Live in the Ocean (click on Deep Ocean)
- Place the Creatures in the Right Food Chain Levels
- Create a Food Chain at Home
- How Does a Food Chain Work?
- Make a Virtual Ocean Food Chain
