Question

In which of the following ecosystems, detritus food chain (DFC) is the major conduit for energy flow?

• A. Pond Ecosystem
• B. River Ecosystem
• C. Forest Ecosystem
• D. Marine Ecosystem

Answer 1

The Correct Option is C

The detritus food chain (DFC) refers to the flow of energy where organic matter is broken down by decomposers and detritivores, rather than being consumed directly by animals as in a grazing food chain. Among the provided ecosystems, the forest ecosystem is where the DFC serves as the major conduit for energy flow. In forest ecosystems, a substantial amount of energy is contained in dead organic matter such as fallen leaves, branches, and trees, which are decomposed by fungi, bacteria, and other detritivores. 

In contrast:

• Pond Ecosystem: Primarily relies on a grazing food chain with phytoplankton and zooplankton serving as the initial energy sources.
• River Ecosystem: Similar to ponds, they mostly function through grazing food chains originating from algae and aquatic plants.
• Marine Ecosystem: Although detritus plays a role, the primary energy flow is through phytoplankton-based grazing food chains.

Therefore, in the context of energy flow through detritus, the Forest Ecosystem is the correct answer as it relies heavily on detritus-based energy pathways.

Answer 2

The detritus food chain (DFC) is the food chain in which energy flows through the decomposition of dead organic matter (detritus). It primarily involves detritivores and decomposers (like bacteria and fungi) breaking down organic material.

Among the options provided:

(1) Pond Ecosystem: In a pond ecosystem, the energy flow is mainly through the grazing food chain (GFC), with primary producers (like algae) supporting herbivores and carnivores.

(2) River Ecosystem: Similar to the pond ecosystem, the river ecosystem also has a more prominent grazing food chain with primary producers (like aquatic plants) being consumed by herbivores.

(3) Forest Ecosystem: The forest ecosystem relies heavily on the detritus food chain. The decomposition of fallen leaves, dead plants, and animals provides the primary source of energy, with decomposers like fungi and bacteria breaking down the organic matter. This makes the detritus food chain the major conduit for energy flow in forest ecosystems.

(4) Marine Ecosystem: While the marine ecosystem does have a detritus food chain, it is typically less significant than the grazing food chain, where phytoplankton form the base for herbivores and larger consumers.

Thus, the correct answer is (3) Forest Ecosystem, where the detritus food chain plays a major role in energy flow.