What is Symbiotic Relationships? Symbiosis is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic. The organisms, each termed a symbiont, must be of different species. In normal words Different species often inhabit the same spaces and share—or compete for—the same resources, they interact in a variety of ways, known collectively as symbiosis . There are five main symbiotic relationships: mutualism, commensalism, predation, parasitism, and competition. Human Symbiotic Relationships. When two species benefit from each other, the symbiosis is called mutualism (or syntropy, or crossfeeding). For example, humans have a mutualistic relationship with the bacterium Bacteroids the taiotetraiotamicron, which lives in the intestinal tract. An interesting example. The symbiotic relationship between...