Since the beginning of their existence, human beings, unable for elaborating by themselves the nutrients that make possible their life, have appealed both animal and vegetable organisms for the satisfaction of their needs; the plants (because of their capacity of producing its own energetic substrates through the photosynthesis process) are those which establish the first step in the ecosystem energy flow.
Along the time, Homo had not been but another biological component in the nature, and his participation (limited to the extraction of those materials that sporadically was finding in his environment) was very far of the creativity that through the time would be the Homo sapiens characteristic. "There was a very long lapse before the agriculture emerge as the more important advance in the human being efforts to achieve their basic satisfactories by the transformation of natural resources" (Hernández X. 1978).
In the plants case, their consideration
as resources surely arose in first instance to the man necessity for obtaining
his food, action that later drove him to knowing other property in the
plants (medicinal, hallucinating, poisonous...) in those species that his
starving invited to consume. Being satisfied his elementary necessities,
the human groups development (starting on their cultural background and
ecological environmental conditions around them) have gone amplificating
and sometimes restricting the magnitude of their useful