For most terrestrial ecosystems, pyramids composed of species abundances, biomass, and energy are similar in that they have a broad base and a narrow top. The primary reason for this pattern is that
A) secondary consumers and top carnivores require less energy than producers.
B) at each step, energy is lost from the system because of the second law of thermodynamics.
C) as matter passes through ecosystems, some of it is lost to the environment.
D) the accumulation of toxic materials in tissues of animals limits the secondary consumers and top carnivores.
E) top carnivores and secondary consumers have a more general diet than primary producers.

Question

Quizplus · Accepted Answer

Pyramids of abundance, biomass, and energy in terrestrial ecosystems have a broad base and a narrow top because at each step from producers to top carnivores, energy is lost due to the second law of thermodynamics. This means that there is less energy available for organisms at higher trophic levels, resulting in a reduction in their abundance or biomass. Therefore, the pyramid becomes increasingly narrow towards the top.

For Most Terrestrial Ecosystems, Pyramids Composed of Species Abundances, Biomass