2.2.17—Ecological pyramids

The shape of a pyramid only makes sense after identifying what is measured and the units used.

Numbers may describe organisms, biomass, energy or productivity. Compare like with like, then explain a narrowing or widening level using transfer and loss.

If levels contain 1,000 kJ m⁻² y⁻¹, 100 and 10, the pattern shows roughly tenfold energy loss at each transfer—not tenfold fewer animals.

Only that measured biomass changes; you cannot call it an energy pyramid without energy units and time.

Never infer trophic efficiency from a picture alone; the variable and units control the interpretation.