An ecosystem is defined as a community of living organisms interacting with their physical environment. This includes both biotic factors, such as plants, animals, and microorganisms, and abiotic factors, like water, soil, and climate. Ecosystems can vary widely in size and complexity, ranging from a small pond to an entire forest. They provide essential services such as nutrient cycling, climate regulation, and habitat provision, and they are fundamental to biodiversity. Understanding ecosystems is essential for conservation and sustainability efforts.