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.
$=$ Each species has a specific position or functional role within the community, called niche.
- According to the Gause's principle, no two closely related species competing for the same resources cannot co-exist indefinitely.
In this case, two herbivorous species are living in the same niche and feeding on phytoplanktons.
$\Rightarrow \quad$ It may be because of the availability of sufficient phytoplanktons and or less number of individuals ofthe fish species.
Recently, it has been revealed that species facing intraspecific competition may evolve mechanism to encourage co-existence rather than exclusion. This is called as resource partitioning.
A sedentary sea anemone gets attached to the shell lining of hermit crab. The association is
$A$ : Fig species and wasp have tight one to one relatioinship.
$R$ : Angiosperms and insects are coevolved to perform a plant-pollinator interaction.
While explaining interspecific interaction of population, $(+)$ sign is assigned for beneficial interaction,$(-)$ sign is assigned for detrimental interaction and $(0)$ for neutral interaction. Which of the following interactions can be assigned $(+)$ for one species and $(-)$ for another species involved in the interaction?