In addition to exogenous factors – climate, geography, etc.. – Human evolution would also be due to cultural and social practices, a recent study of Native American tribes of Brazil said.
The cultural and social environment – tradition, transmission, rites and practices – influence the morphological changes of the man. Research conducted by geneticist Francisco Salzano and his team, the University of Rio Grande do Sul , proved it. The results are published Dec. 19 in the Proceedings of the National Academy of Sciences magazine.
Scientists have indeed analyzed the human characteristics of 1,203 members of six South American tribes in the Brazilian Amazon. Of these, a community, Xavantes, differ significantly in terms of shape and silhouette, compared to neighboring tribes. The members of Xavantes community possess larger heads, bigger and stronger faces , and more amazed nose.
These characteristics have evolved about 1500 years after the tribe was separated from the Kayapó. “A remarkably rapid morphological differentiation” as quoted by Francisco Salzano LiveScience . About four times faster than comparable changes observed in other tribes.
For researchers, it is the social and cultural determinants that are responsible for these changes.Xavante in the village of Sao Domingo, ¼ of the population is derived from the son of one head, Apoena, who had five wives. Sexual practices of the tribe indeed allow people to generate a large popular offspring. Thus, any trait of dominant males can quickly dominate the population.
The researchers plan to create a database of cultural and biological data to discover other examples of the influence of human evolution of culture.
Abdullah Al Abbadi
Sources : Livescience