Competitors are heterotrophic organisms that compete with others for food and resources within the food chain, and may feed or become food for an organism of the same size or larger. It was previously thought that the microbial loop was built upon the principle of a fixed size relationship between the predator and its prey. Here are three organisms that demonstrate the paradigm shift away from this idea, proving that size doesn’t matter when it comes to predator/prey relationships in the microbial loop. Some of these competitors consume prey in copious amounts, resulting in a diminished population and density of a microbial species. Therefore, competitors have a large impact on both micro and macro biota in their ecosystem.