Key Ecosystem Distinctions — NEET Biology

Which of the above statements about energy flow and ecological pyramids are correct? S1: The flow of energy in an ecosystem is unidirectional, with a significant amount of energy being lost as heat at each successive trophic level according to the second law of thermodynamics. S2: Primary productivity is defined as the rate of formation of new organic matter by consumers, and it is expressed in terms of gm⁻² or kcal m⁻². S3: A given species, like a human being, can occupy multiple trophic levels simultaneously depending on its feeding habits. S4: In an aquatic ecosystem, the grazing food chain (GFC) is often the major conduit for energy flow, while in terrestrial ecosystems, the detritus food chain (DFC) typically accounts for a larger fraction of energy flow. S5: Ecological pyramids of number and biomass can sometimes be inverted, but the pyramid of energy is always upright because of the 10% law. S6: Plants typically capture 50% of photosynthetically active radiation (PAR) to sustain the entire living world.