Video-Enhanced Lesson

This video-enhanced lesson focuses on symbiosis and ecological relationships. Using sharks and marine species as examples, students will investigate the many ways that species that live in close proximity to each other might interact in an ecosystem, and will then explore the ways that ecosystems can be thrown out of balance, often as a result of human action. (Grades 9-12)

Longliners -- which set lines that can be up to 15 miles long and are laden with hundreds or thousands of baited hooks -- pose an increasingly potent threat to sharks.

Hardy Jones, the filmmaker behind NATURE's "The Dolphin Defender," is a former journalist with CBS News and UPI. NATURE Online interviewed him in May 2005.

Chemical pollution, including pollution from polychlorinated biphenyls (PCBs), has been linked to health and reproductive problems in dolphins and orcas.

Even as our actions have imperiled the red knot, we can also preserve the species, by regulating the fishing industry and keeping clear of the beaches that the knots rely on during migration.

Romulus Whitaker is a reptile conservationist who has spent the past 40 years conserving the most endangered crocs. NATURE caught up with him to "talk crocs" in January 2007.

Lion conservationists are enlisting every ally they can find. In early 2006, for instance, two groups held a "lion summit" in Johannesburg, South Africa.

Wayde Roberts is a Natural Resource Officer at Manitoba Conservation. He has worked with polar bears in Churchill, known to many as the polar bear capital of the world.

View additional resources, online and in print, for NATURE's "Flight School."

Joseph Duff is one of the leaders of Operation Migration, a nonprofit organization that is using aircraft to restore migrating populations of whooping cranes.