The functional role of an ecosystem encompasses various interactions among organisms and their physical environments. Ecosystems play a critical role in maintaining the balance of energy flow and nutrient cycling, supporting diverse forms of life. They provide essential services such as pollination, decomposition, and water purification, which are crucial for both ecological health and human survival. Ecosystems can vary widely in size and complexity, from small ponds to vast forests, impacting local and global biodiversity and climate regulation.