THE ROLE OF HUMANS IN THE EVOLUTION OF THE NORTH AMERICAN PINYON PINES

Abstract

The North American pinyon-pines ( Pinus subsec. Cembroides) have evolved since geological times in response to environmental factors. As a result of man?s incursion in the pinyon-pine forests 20 000 years before the present, these plants have experienced a continuous impact due to their utilization for nuts, firewood, wood, resin, pollen, etc. This utilization has modified ecological relations, population attributes, community structure and other characteristics, which may be at the genetic and evolutionary level. This essay presents an analysis of the utilization as the driving forces of the evolution of pinyon-pines based on the development of the means of subsistence and the social and political organization of men. The model to evaluate selective changes in the pinyon pines was the route of evolution of other species managed by men: the continuum of wild-weedy-domesticated forms. We found antagonistic biological responses, suggesting that pinyon pines are in a transitional state between wild and modified environments, though in terms of biological evolution the evidences of the effects of human populations in their diversification are lacking.