Question

Choose the correct option with respect to statements X and Y.

X: Marine ecosystems have lesser trophic levels than terrestrial ecosystems.

Y: Most of the phytoplankton is available for consumption and assimilation by primary consumers in aquatic ecosystems.

• A. Both X and Y are true
• B. Both X and Y are false
• C. X is true and Y is false
• D. X is false and Y is true

Answer 1

The correct option is D X is false and Y is true

In marine ecosystems, phytoplanktons carry out most of the photosynthesis that occurs. Phytoplanktons are small organisms like diatoms with extremely simple structures, so most of their primary production or biomass is consumed by grazing organisms that feed on them. In contrast, a large fraction of the biomass that land plants produce, such as roots, trunks, are complex and cannot be consumed by herbivores for food. This is the reason why terrestrial ecosystems have smaller food chains or lesser trophic levels than marine ecosystems.