Convergence:
Two structures (Human social systems and environmental ecosystems) that have evolved differently but share a common ancestry, begin to converge at a common center (evolutionary capacity).
Ecology is the study of organisms and their relationship to their environment. Human Ecology is the study of humanity and their relationship with their environment(s). This requires that we distinguish between social and the natural, because humanity, especially in Western Modern Society evolved within the parameters of a separate environmental order with socially constructed norms, rules, patterns, processes, and organizations around economic principles vs. ecological.
When human development and technologies converge with the basic principles of ecology and design we will just be beginning our journey for (sustainable) development. In order to understand how to do something we have never done before, or even mimic/ model environmental ecology, we look to nature as a designer of life-support systems. Our mental models that were created from learning how to separate humanity from nature, and re-create reality from our own collections of parts manipulated into linear cause and effect scenarios served its purpose. Now it is time for the ultimate convergence when we put the pieces together again, in accordance with the systems in which everything exists or has come to be.