An ecosystem is a community of plants and animals living in relationship with each other in a given environment. Nutrition is the main mechanism by which energy is transmitted from one species to another. In the food chain, plants produce their own food with carbon dioxide and minerals and are eaten by herbivores which in turn are consumed by carnivores, themselves eaten by super predators. When an organism dies the organic matter is decomposed by worms, insects and microorganisms resulting in minerals used by plants, completing the food chain. There are aquatic, terrestrial and atmospheric ecosystems which can vary greatly in size, as a lake or ocean.

Originally released by QA International, 2005. Streaming video file encoded with permission for digital streaming by Infobase on May 06, 2015.

Ecosystems (1:31).