Question

In an aquarium two herbivorous species of fish are living together and feeding on phytoplanktons. As per the Gause’s Principle, one of the species is to be eliminated in due course of time, but both are surviving well in the aquarium. Give possible reasons.

Answer 1

Gause’s principle

According to Gause’s ‘competitive exclusion principle’, closely related species which compete for the same resources cannot coexist indefinitely in a niche. The superior species will outgrow or eliminate the inferior species.

Reasons behind survival of both the species

The possible reason for the survival of both the fishes are mentioned below:

● Abundance of phytoplanktons: The competitive exclusion principle is true only if resources are limited. There may be a possibility where the phytoplanktons present in the aquarium are quite abundant to support the food requirements of both the species of fish.

● Resource partitioning: Species facing competition can evolve to coexist rather than to compete. Fishes may be feeding on different species of phytoplanktons or at different times exhibiting different foraging patterns. This is called resource partitioning.