All questions of Functions of an Ecosystem for BPSC (Bihar) Exam

Both statements are correct.

1. In a pyramid of biomass, the weight (biomass) of all individuals in each trophic level is considered instead of counting the number of individuals. This gives a more accurate representation of the energy available in each trophic level, as larger organisms typically have more energy stored in their tissues.

2. The pyramid of biomass is structured with producers at the bottom, representing the largest amount of biomass in the ecosystem. Producers (e.g., plants) convert sunlight into energy through photosynthesis and form the base of the food chain. As energy transfers up the trophic levels through consumption, energy is lost in the form of waste and heat, resulting in a decrease in biomass as you move up the pyramid. This is why the biomass of producers is at the bottom of the pyramid, as they represent the largest amount of available energy in the ecosystem.

Statement 1 is correct. In most terrestrial ecosystems, the pyramid of biomass has a large base of primary producers with smaller trophic levels on top, reflecting the greater biomass of plants compared to herbivores and carnivores.

Statement 2 is correct. In many aquatic ecosystems, the pyramid of biomass can be inverted, meaning that the biomass of primary producers (phytoplankton) is less than that of the higher trophic levels (zooplankton and fish). This inversion occurs because the primary producers reproduce and are consumed rapidly, maintaining a lower biomass.

Statement 3 is incorrect. The energy pyramid always remains upright because energy flow in an ecosystem follows the laws of thermodynamics, with energy decreasing at each successive trophic level due to inefficiencies in energy transfer.

Therefore, the correct answer is Option B: 1 and 2 Only.

1. Gaseous Cycle - Carbon Cycle: Correct- The Carbon Cycle is a gaseous cycle where carbon dioxide circulates between the atmosphere and living organisms.

2. Sedimentary Cycle - Nitrogen Cycle: Incorrect- The Nitrogen Cycle is primarily a gaseous cycle, involving the atmosphere as a major reservoir.

3. Gaseous Cycle - Water Cycle (Hydrologic Cycle): Correct- The Water Cycle is a gaseous cycle driven by solar energy, involving processes like evaporation and precipitation.

4. Sedimentary Cycle - Phosphorus Cycle: Correct- The Phosphorus Cycle is a sedimentary cycle, as phosphorus is primarily stored in the earth's crust.

Thus, pairs 1, 3, and 4 are correctly matched, while pair 2 is incorrectly matched. Hence, only two pairs are correctly matched.