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Objectives
To illustrate the independence of living things in the ocean.
Materials
- recycled materials, such as paper
- art materials (crayons, paints, brushes, etc.)
Background
Here's one example of the interdependence of living things under the ocean waves. Kelp forests support on amazing diversity of life — molluscs, crustaceans, worms, fish, and countless other tiny but tasty species. 5o, when kelp beds grow thin, all these species — plus seals, bold eagles, sea otters, and other animals that eat them — must search for other homes. It took about 150 years before scientists understood the relationships among these species. In the meantime, hunters wanting glossy pelts nearly drove sea otters to extinction.
Scientists finally noticed that wherever the otters disappeared, kelp forests disappeared, too, as did seals and bold eagles. That’s because the otters love to eat purple sea urchins, which dine on kelp. But once too many hungry urchins munch kelp loose from the ocean floor, waves wash it away.
Today, sea otters are recovering in Alaska and British Columbia because they are protected. And wherever sea otters live, you will also find a healthy balance of sea urchins, kelp forests, fish, seals, and bald eagles!
In the same way, overfishing of triggerfish on coral reefs near Kenya allowed rock-boring sea urchins to thrive. This situation has thrown the entire ecosystem off balance. When fishermen caught too many sand eels off Shetland Island shores, arctic terns, puffins, and other birds had nothing to feed their chicks. As a result, the birds stopped breeding.
Procedure
- Tell students that they will decorate their classroom like on ocean ecosystem (such as a coral reef, kelp forest, etc.). Using this chart and maps, describe the kind of animals and plants found in some types of ocean ecosystems.
- Divide students into small groups. Each group selects their favourite ocean creature or plant and finds out what it needs to live.
- Ask students to construct their animal or plant as well as the elements that it needs. Use recycled materials where possible.
- Each group decorates a part of the classroom with their constructed ecosystem and presents it to the class.
- Discuss with students what might happen to their animal or plant if people disrupt any part of the ecosystem.
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