Ecosystem

🎯 How This Word Works in UPSC Writing

A functional unit in which a biotic community interacts with its abiotic environment through energy flow and nutrient cycling. The examinable division is between structure and function. Structure covers species composition and physical organisation such as stratification, while function covers productivity, decomposition, energy flow and nutrient cycling, and it is the functional attributes that determine whether a disturbed system recovers. The unifying rule is that energy flow is unidirectional, entering as sunlight and leaving as heat, whereas nutrients cycle indefinitely between biotic and abiotic pools. The policy vocabulary built on this is ecosystem services, conventionally grouped as provisioning services such as food and timber, regulating services such as flood control and pollination, cultural services such as recreation and spiritual value, and supporting services such as soil formation, which underpin the rest and are the easiest to destroy unnoticed.