All organisms require resources to grow, reproduce, and survive. All the resources are limited. Hence, organisms compete to get the resources. Competition is an interaction which takes place among organisms whenever two or more organisms require the same limited resource.
Ecological interactions can be intra-specific or inter-specific. Intra-specific interactions are those that occur between individuals of the same species, while interactions that occur between two or more species are called inter-specific interactions.
Competition between organisms plays an important role in ecology and evolution, it serves to limit organism population and thereby ensure its sustainability and survival.