Under the Sea
Under the Sea
Students consider how various types of plastics could impact different marine organisms through two broad types of plastic impacts: entanglement and ingestion. Next, students examine plastic impacts across six trophic levels of organisms: producers, primary consumers, secondary consumers, tertiary consumers, apex predators, and decomposers. Finally, groups investigate different ecosystems to apply what they learned about specific impacts of plastics on a wider variety of marine organisms.
6 - 8
Oceanography, Ecology, Conservation, Biology
This resource is also available in Spanish.
Nearly 250,000 species are known to live in the oceans. Meanwhile, as many as 91 percent of ocean species still have not been classified, and 95 percent of the oceans remain unexplored. Ocean food webs, therefore, are complex and difficult to study. In some ways, they seem like a bizarre mirror image of terrestrial food webs. Stationary creatures, like coral, seem like plants, but are actually consumers (although they live symbiotically with photosynthetic algae called zooxanthellae). Huge animals, such as the whale shark, subsist primarily on plankton, while tiny creatures, such as seahorses, are predators. The water column contains so much detritus, known as marine snow, that many filter-feeding animals that eat plankton could also be considered decomposers. Adding to the confusion, many marine animals are opportunistic feeders that will take advantage of almost any available food source, so they could be considered to occupy more than one trophic level. This confusion may become apparent to some of the students as they learn more about the marine food web. Nevertheless, understanding how organisms in different habitats and niches interact with plastics of different sizes allows students to appreciate both the beauty of the ocean ecosystem and the complexity of dealing with the problem of plastics.
Recommended Prior Activities
- Autopsy of an Albatross
- Follow the Friendly Floatees
- Magazine Design Workshop I
- Plastics Aplenty
- The Life Cycle of Plastics
Students’ participation in the trophic level card sorting discussion and their exit tickets provide insights into students’ developing understanding and ideas about the cycling of matter in marine ecosystems; these should be collected by the teacher. Their completion of the Plastic Impacts handouts demonstrates their ability to determine the main ideas in scientific texts; these should be kept in the publishing teams’ project folders.
Extending the Learning
Consider using these related encyclopedic entries to build a deeper understanding of each trophic level and different roles in the food web.
What You’ll Need
Materials You Provide
- Internet Access: Required
- Tech Setup: 1 computer per classroom, Projector, Speakers
- Plug-Ins: Flash
- Large-group instruction
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June 1, 2023
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