Why are there so few ecosystems with more than four levels of consumers?
A)because biomass decreases by about 90% at each trophic level moving up
B)because top consumers compete with and kill each other with increasing population size
C)because consumers at these highest trophic levels typically form social groups that stop reproducing at high densities
D)because predators at the highest trophic levels simply are not intelligent enough to hunt other top predators

Question

Quizplus · Accepted Answer

Biomass decreases significantly at each higher trophic level due to energy lost through metabolism and heat. As a result, there simply may not be enough energy left to sustain a higher trophic level.

Answer: B 
 As the population size of top consumers increases, competition for food and resources also increases, resulting in cannibalism or other forms of lethal competition. This reduces the number of top consumers in the ecosystem.

Answer: C 
 Consumers at higher trophic levels are typically larger and require more resources, which can be limited in the ecosystem. Additionally, forming social groups may provide benefits such as hunting in packs, but also reduces the number of breeding individuals.

Answer: D 
 This is an incorrect statement. Predators at the highest trophic levels have evolved sophisticated hunting techniques and strategies to succeed in hunting other top predators. However, even if a predator is successful in capturing a top predator, the energy required to do so is significant and may not be enough to sustain the predator population over time.

Why Are There So Few Ecosystems with More Than Four