National Geographic
National Geographic: Marine Ecosystems and Biodiversity
In this unit students explore major marine ecosystems by locating them on maps. Students use marine examples to learn about energy transfer through food chains and food webs and then they discuss how food webs can illustrate the health...
Missouri Botanical Garden
Missouri Botanical Garden: Freshwater Ecosystems
At this site from the Missouri Botanical Garden, you can learn about the wide variety of plant and animal life in or around fresh water ecosystems. Click on the links to "wetlands," "Ponds and Lakes," or "Rivers and Streams" to view...
Missouri Botanical Garden
Missouri Botanical Garden: How the Ocean Refreshes Itself
Watch the animated illustrations to see how the nutrients at the bottom of the ocean get circulated to the top. This upwelling is necessary in order to maintain a healthy ocean.