The graph shows commensalism type of interaction between species 1 and 2. Species grows with time when grows alone. When species 1 and 2 grow together, species 1 grows more whereas no change is shown by species 2. In commensalism, one organism gets benefits and other derives niether benefit nor harm. In amensalism, one species harms another species without getting any kind of benefits. In mutualism, both species benefits each other. In competition both organisms are harmed.
