The chapter presents the construction of evolutionary mechanisms at the level of mesoevolution. The author focuses on the role of group selection and intergroup competition as a driving force of evolution. Groups that were better adapted to their environment and cooperated more effectively increased in size and had a better chance of success in encounters at the expense of smaller groups with inferior behavioral patterns. The persistence and speed of the spread of innovations among groups depended on the size of populations, the intensity of migrations, and the nature of intergroup interactions. The complex mechanism of formation, selection, and diffusion of new skills involves the interaction of such factors as behavioral patterns, niche construction, changes in selection criteria, fixation in the genetic bases of heredity, as well as in transmitted cultural patterns. The cycle of social and cultural change acted faster than the mechanism of evolution through gene drift and mutations. Evolution has used genes to fix the basis for the most stable behavioral patterns during the change of generations. The mechanism of formation of new providing structures in response to challenges-threats and challenges-opportunities includes, in addition to different types of attempts (trials), ingredients and mechanisms of fixation. The author shows that Arthur Stinchcombe’s functional scheme is a potentially rich constructthe gathering of wood capable of explaining complex evolutionary processes through a network of reinforcing and weakening links between factors. He pays particular attention to the role of costs (losses, damage) from the activity of providing structures, which in turn generate new challenges and hence new trials, leading to a spiral of development. The explanation for the equal level of sapience of all human populations at the death of all hominin lateral branches consists in the systematic accumulation of polar consequences of two types of intergroup relations: parity and disparity.