During the period 1950-2000, the agricultural development model which is based on changes in technological improvement and commodities allowed a significant increase in global agricultural production. Beginning in the 70's, this model was consolidated in South American emerging countries as a result of the combination of government policies and strategies of large private groups. It has raised questions about the environmental and socio-economic consequences, particularly when adopted in family farming systems. The authors found changes and resistance in agrarian structures, farming systems and demographic aspects related to the dissemination of this model and their adoption by the farmers. The study was conducted in the state of Paraná - Brazil in two areas representing the history of rural diversity on the technical, socio- economic and human development dimensions. The work was based on the analysis of statistical data of the agricultural census (1970, 1975, 1980, 1985, 1996 and 2006), on the demographic census (1970, 1980, 1991, 2000 and 2010) and on the agricultural official database of the State of Paraná Agricultural Agency (1970-2012). The data were compared between the two areas and analyzed in alignment with the St ate of Paraná standards. The data exhibit a decrease in the numbers of farms and of the rural population, with a focus on the significant departure of young people and of women especially. The results also s how a big reduction in the numbers of the middle- size farms, caused by land concentration and proliferation of extra- small farms in the suburbs of the cities. They also demonstrate the expansion of soybeans crops in both regions, however with differentiated modalities of insertion in the farming systems, and finally the recent survival of family farming systems despite the severe changes observed in the period.