Consider the following:
1. Grassland
2. Pond
3. Forest
Which among the above is / are example(s) of grazing food chain?

Answer: [B] Only 1 & 2

Cattle and rodents are the main grazers in a grassland, while zooplankton are the main grazers in a pond or lake. Usually up to 50% of the net primary production is grazed on by these animals in their respective ecosystems and the remaining 50% goes to the decomposer organisms as dead organic matter. Therefore, in these ecosystems, the food chain is herbivore based and herbivores are considered important consumers. This is classified as a grazingJood chain. In a forest ecosystem, the dominant primary consumers (herbivores) are the insects, which usually consume less than 10% of the net primary production. The rest (90%) is consumed later as dead plant material by the small detritus feeding animals, such as microarthropods, Oligochaetes and micro-organisms like protozoa, fungi, actinomycetes and bacteria.

The animals consume the detritus and process it in their gut by reducing it into small pieces and sometimes digesting it partially of fully, thus making organic materials available for bacterial and fungal attack. These macroorganisms also act as food for many soil animals. This food chain is classified as a detritus or decomposer food chain. The detritus food chain exists in every ecosystem and is very important for the circulation of materials.  Even in a grazing food chain, the faeces and urine of grazing herbivores ultimately come to the decomposer pathway. [Fundamentals of Ecology, TMH]

This question is a part of GKToday's Integrated IAS General Studies Module