JNTU B.Tech II ENVIRONMENTAL STUDIES Previous Question Paper (November/December - 2020 - R15)

An ecosystem is a functional unit of nature where living organisms interact with each other and with their non-living (abiotic) physical environment. It is a self-sustaining system characterized by energy flow and nutrient cycling.

The components of an ecosystem are classified into two main categories:

• Abiotic Components: These include physical and chemical factors such as sunlight, temperature, precipitation, water, soil, and inorganic nutrients (C, N, P, S).
• Biotic Components: These include all living organisms, categorized by their trophic roles:
  • Producers (Autotrophs): Organisms like plants and algae that synthesize food using solar energy.
  • Consumers (Heterotrophs): Organisms that depend on producers for food, including primary (herbivores), secondary, and tertiary consumers.
  • Decomposers (Saprotrophs): Microorganisms like bacteria and fungi that break down dead organic matter, recycling nutrients back into the soil.

An ecological pyramid is a graphical representation of the relationship between different trophic levels in an ecosystem. It depicts the number of organisms, biomass, or energy content at each level, with producers at the base and top carnivores at the apex.

There are three main types:

• Pyramid of Numbers: Represents the count of individuals at each trophic level.
• Pyramid of Biomass: Represents the total dry weight of living matter at each level.
• Pyramid of Energy: Always upright, representing the total amount of energy available at each level, illustrating the 10% law of energy transfer.