Question

Why are trophic levels limited to 3–4?

Answer 1

At each transfer, on average, only about 10% of the energy at one level is passed on to the next; much is used in respiration and other life processes or lost as heat and waste. Consequently, little energy remains to support organisms at higher levels. Food chains are therefore usually short, commonly about 3–4 levels and generally no more than 4–5.