JNTU B.Tech II ENVIRONMENTAL STUDIES Previous Question Paper (March/April - 2021 - R15)

The ecosystem functions through the continuous flow of energy and the cycling of nutrients, which maintain the stability of the environment. The primary functions are:

1. Energy Flow: Energy enters the ecosystem from the sun and is captured by producers (plants) through photosynthesis. It then flows through the food chain from producers to consumers (herbivores, carnivores) and finally to decomposers. This process follows the laws of thermodynamics, where energy is transferred and partially lost as heat at each trophic level.
2. Nutrient Cycling: Essential elements like carbon, nitrogen, oxygen, and phosphorus circulate between the biotic (living) and abiotic (non-living) components of the ecosystem. Decomposers play a critical role in breaking down organic matter to release these nutrients back into the soil, water, and atmosphere for reuse.
3. Primary Production: This is the rate at which solar energy is converted into organic compounds by producers, forming the base of the food web.
4. Regulation: Ecosystems regulate various processes, including climate control, water purification, and soil formation, which provide life-supporting services to all organisms.

Ecological pyramids are graphical representations of the relationship between different trophic levels in an ecosystem. They illustrate the distribution of organisms, energy, or biomass at each level, starting from producers at the base and moving up to top-level consumers. There are three main types:

1. Pyramid of Numbers: Represents the total number of individual organisms at each trophic level. It is usually upright in grassland ecosystems but can be inverted in forest ecosystems (where one tree supports many insects) or parasitic food chains.
2. Pyramid of Biomass: Represents the total dry weight of living matter at each trophic level. It is generally upright in terrestrial ecosystems, but in aquatic ecosystems, it can be inverted because the biomass of phytoplankton (producers) is often smaller than that of zooplankton and fish (consumers) due to their rapid turnover rate.
3. Pyramid of Energy: Represents the total amount of energy available at each trophic level per unit area per unit time. This pyramid is always upright because energy is lost as heat at each transfer, adhering to the 10% law, which states that only about 10% of energy is passed to the next higher trophic level.