The predator prey category primarily focuses on the relationships of organisms that consume another or thus be consumed. This relationship regulates populations and in turn the effects that some of the larger scale effects that some microbes can have. If the population of a predator species suffers, it can mean the mass outbreak of the prey as it has less to keep it in check. In return, if the prey species numbers dwindle it means less food for the consumer and it will struggle as well. An entire food web cycle can be disturbed just from the difficulties encountered by one part of the web, the system itself suffers from the effects.