It depends on our perspective through which we try to evaluate evolution. If complexity in body design is the parameter to define evolution, then human beings are more evolved than bacteria. Bacteria are unicellular while human beings are multicellular. Bacteria show cellular level of organization, while human beings show organ system level of organization. In terms of complexity human beings are definitely highly evolved compared to bacteria.But when we compare the ability of survival, then situation is quite opposite. Human beings are living in almost every part of the earth but they can live only on land. Moreover, in extreme environmental conditions, human beings make artificial facilities to counter the adverse conditions. This means their body is not adapted to withstand extreme climatic conditions. Bacteria, on the other hand, are known to be present almost everywhere on earth. They are known to live even in some of the harshest conditions; like Sulphur spring, crater of volcano, etc. Bacteria can survive in highly acidic environment and they can survive extreme temperatures. From this angle, bacteria can be considered as more evolved than human beings.