Question

Assertion : DFC may be connected to the GFC chain at some levels.
Reason : After death, organisms of GFC are acted upon by decomposers and some organisms of DFC are preyed upon by GFC animals.

Answer 1

A food chain is a chronological series of organisms each depending on other for food. It also explains the feeding pattern or relationship between living organisms.

Different organisms occupy different levels in the food chain and each level is referred to as trophic levels.

There are two types of food chain : detritus food chain (DFC) and grazing food chain (GFC).

• Detritus food chain (DFC) : It begins with dead and decaying organic material. It is composed of decomposers like bacteria and fungi (heterotrophic organisms) which meet their energy requirements by degrading dead organic matter (detritus).
• Grazing food chain (GFC) : It begins with autotrophs like green plants, cyanobacteria, etc., that are able to synthesise their own food by photosynthesis and pass on the energy to herbivores and further to carnivores.

Detritus food chain may be connected with the grazing food chain at some levels. If an organism dies, the decomposers (bacteria and fungi) act on them to decompose the material. Even some of the organisms of the detritus food chain are prey to the grazing food chain. For example, earthworms (a part of DFC) are detritivores that are eaten up by small birds (a part of GFC) which can further be eaten up by kites or cats.

Figure : Detritus food chains connected with grazing food chain

Some organisms like cockroaches, crows which are omnivores, play an important role in the interconnections of DFC and GFC. These interconnections of food chains make it a food web.

Hence both the assertion and reason are true and the reason is the correct explanation of the assertion