What are ecosystems, and what do different ecosystems have in common? How are they affected by human activity? From the diverse rainforests of the tropics to the smallest microbial communities, ecosystems support life on Earth. This album reveals the ecological relationships that create these living systems of energy transfer and explores some of the key processes that occur. It goes on to show how these complex systems can be affected by external influences and harmed by the activities of humans. This material forms part of The Open University course S396 Ecosystems.