University Corporation for Atmospheric Research
Ucar: The Carbon Cycle
A comprehensive introduction to the carbon cycle. The cycle of atoms between living and non-living things is known as a biogeochemical cycle. The most common of these are the carbon and nitrogen cycles.
TeachEngineering
Teach Engineering: Moebius Strips
In this activity, students make Moebius strips and use them to demonstrate the interconnectedness of an environment. They will explore the natural cycles (water, oxygen/carbon dioxide, carbon, nitrogen) within the environment.
Other
Marietta College: Ecosystems
Complete illustrated discussion of energy flow within ecosystems, including discussions of trophic levels, ecological pyramids, food chains and webs, biological magnification, and cycles.
Ohio State University
Ohio State University: Concepts of Plant Ecology
An advanced discussion of plant interactions and relationships. Energy flow, nutrient cycling and succession are discussed. Try the quiz to check your understanding.
University of Illinois
University of Illinois Extension: Energy and Ecosystems Use Some Lose Some
Life on Earth is possible because energy flows one way through ecosystems, while matter cycles endlessly. Water and elements, such as carbon, nitrogen, phosphorous, and sulfur are examples of matter that cycles through ecosystems.