Question

In a comparative study of terrestrial ecosystem and aquatic ecosystem, it may be observed that:

• A. primary and secondary consumers are similar
• B. the abiotic components are almost similar
• C. the biotic components are almost similar
• D. both biotic and abiotic components are different

Answer 1

The correct option is B

the abiotic components are almost similar

Terrestrial ecosystems usually have lesser number of trophic levels than the aquatic ecosystems. This difference between terrestrial and marine ecosystems is due to differences in the fundamental characteristics of land and marine primary organisms. In aquatic ecosystems, phytoplankton carries out most of the photosynthesis, while plants do most of this work on the land. Phytoplanktons are small organisms with extremely simple structures, so most of their primary production is consumed, and used for energy by aquatic animals that feed on them. In contrast, a large fraction of the biomass that land plants produce, like the roots, trunks, and branches, cannot be used by herbivores for food, so proportionately less of the energy fixed through primary production travels up the food chain. Because of these energy losses, most terrestrial ecosystems have not more than five trophic levels, while marine ecosystems generally have seven.