An ecosystem has very high productivity, abundant rain, and long growing seasons with relatively high temperatures.Strands in its food webs have no more than three or four trophic levels.Which of these factors is least likely to affect the number of trophic levels in the food web?
A) Energy is lost at every trophic level, so the web can only support a limited number of levels.
B) Top predators limit the number of trophic levels because they have no predators.
C) Humans control all major food webs and maintain the number of levels by predation.
D) Having fewer levels makes it easier for a web to recover after a disturbance.
E) The presence of omnivores limits NPP and possibly the number of trophic levels.

Question

Quizplus · Accepted Answer

Humans do not necessarily control all major food webs, and even if they do, they do not necessarily maintain the number of trophic levels by predation. Therefore, this factor is the least likely to affect the number of trophic levels in the food web. The other options (A, B, D, and E) all provide valid explanations for why the number of trophic levels in a food web may be limited.

An Ecosystem Has Very High Productivity, Abundant Rain, and Long