Symbiosis refers to a relationship in nature, between two organisms. It can exist in 3 forms. These are mutualism, commensalism and parasitism. Each of these is made up of different symbiotic systems in which at least one of the organisms benefits from the relationship. In a mutual relationship, both organisms will benefit in one way or another. In a commensal relationship, one organism will benefit from the partnership, while the other will neither be harmed nor benefited. Finally, in a parasitic relationship, one organism will benefit from the partnership while the other organism will be harmed or even killed. This article focuses on the mutual symbiosis found in nature (Patek, 2011). Symbiotic mutualism is a partnership in which both organisms will benefit from the relationship. This relationship beneficial to both organisms is therefore indirectly beneficial to the ecosystem. An example of this relationship, found in nature, is that of rhizobia and legumes. In this relationship, both the rhizobium and the legume it contends with benefit, in that the legume is enriched in nitrogen and amino acids by the rhizobium, while the rhizobium receives the important organic molecules that act as a source of energy for bacteria. (Kiers et al., 2003). The nitrogen present in this reaction is a very important nutrient, as it plays a driving role in many photosynthetic processes. This process is carried out by rhizobia bacteria which attach to a nodule on the root hairs of the legume, capture nitrogen from the air and convert it to a form usable by plants (NH4) using the enzyme nitrogenase , and receive growth in return. molecules it needs (Denison & Kiers, 2004). Both organizations benefit from the partnership they share; however, this...... middle of paper ......c relationship with the roots of legumes. However, this symbiotic relationship, in particular, can exist in two forms: mutual or parasitic. Although the parasitic strand is the largest among rhizobia populations, the parasitic strand exists, but it is slowly eradicated by the ever-changing legumes. The researchers studied the different strands of the bacteria and tried to draw conclusions about the effectiveness of the two separate strands. Each concluded that although the parasitic strands have much less work to do to obtain the essential molecules to facilitate their growth, they obtain a significantly lower amount of growth molecules, if any. Indeed, through the evolutionary pathways of the legume roots, the parasitic strand is selected and the legume favors the more hardworking mutual strand of the rhizobia bacteria..