JNTU B.Tech II ENVIRONMENTAL STUDIES Previous Question Paper (March - 2022 - R13)

An ecosystem is a functional unit of nature where living organisms (biotic components) interact with their physical environment (abiotic components) to create a stable, self-sustaining system through the exchange of energy and nutrients.

The ecosystem functions through two primary processes: energy flow and nutrient cycling. Energy enters the system primarily from the sun, is captured by producers via photosynthesis, and is transferred through trophic levels with significant loss as heat. Simultaneously, essential nutrients like carbon, nitrogen, and phosphorus are continuously cycled between the biotic community and the abiotic environment, ensuring the sustainability of life.

A food chain is a linear sequence of organisms through which energy and nutrients are transferred as one organism eats another. A food web is a complex, interconnected network of multiple overlapping food chains, representing the actual feeding relationships in an ecosystem.

In a terrestrial ecosystem, the components of a food chain are:

• Producers (Autotrophs): Green plants and trees that convert solar energy into chemical energy through photosynthesis. They form the first trophic level.
• Primary Consumers (Herbivores): Animals such as insects, deer, or rabbits that feed directly on producers. They represent the second trophic level.
• Secondary Consumers (Primary Carnivores): Organisms like frogs, small birds, or snakes that feed on primary consumers.
• Tertiary Consumers (Secondary Carnivores): Top predators such as hawks, lions, or tigers that feed on secondary consumers.
• Decomposers (Detritivores): Microorganisms like bacteria and fungi that break down dead organic matter into simpler inorganic substances, returning nutrients to the soil to be reused by producers.