Previous Year Question

An Ecosystem is a Structural and Functional Unit of nature in which living organisms continuously interact with their physical environment. It is generally an Open System because Energy and Matter are continuously exchanged between the ecosystem and its surroundings. Solar energy enters the ecosystem, while heat generated through respiration and other biological processes is released into the environment. Similarly, water, gases, nutrients, and organisms move between different ecosystems.

An ecosystem consists of both Biotic Components and Abiotic Components. Biotic Components include Producers, Consumers, and Decomposers. Green plants and algae prepare organic food through Photosynthesis, whereas herbivorous and carnivorous organisms obtain energy as Consumers. Decomposers such as bacteria and fungi break down dead organic matter and return nutrients to the environment. Abiotic Components include sunlight, temperature, water, air, soil, and minerals, which influence the growth and distribution of organisms.

Every ecosystem has its own Productivity, which represents the rate of Biomass production or energy accumulation per unit area or volume over a specified period. The total organic matter produced by Producers through Photosynthesis is called Gross Primary Productivity (GPP). The productivity remaining after subtracting the energy consumed in producer respiration is known as Net Primary Productivity (NPP). Additionally, the rate at which Consumers produce new biomass is called Secondary Productivity. The level of productivity depends on sunlight, water, temperature, nutrients, and other environmental conditions.

Ecosystems form an important foundation for natural resources and Ecosystem Services. Forests, grasslands, rivers, lakes, and oceans are examples of natural ecosystems, while agricultural fields and man-made Aquariums may function as artificial ecosystems. These systems provide services such as food, water, timber, Nutrient Cycling, soil formation, and climate regulation. According to Thermodynamics, a Closed System can exchange energy with its surroundings but not matter; in contrast, an Open System exchanges both energy and matter. The continuous exchange of both forms the basis of the functioning of natural ecosystems.