[spynxic]

natural (comparative more natural, superlative most natural) 1. That exists and evolved within the confines of an ecosystem. 2. Of or relating to nature. 3. Without artificial additives. 4. As expected; reasonable. ------ mechanical (comparative more mechanical, superlative most mechanical) 1. (now rare) Characteristic of someone who does manual labour for a living; coarse, vulgar. 2. Related to mechanics (the branch of physics that deals with forces acting on mass). 3. Related to mechanics (the design and construction of machines) 4. Done by machine.

(These definitions were sourced from Wiktionary)

I hope these senses of the terms natural and mechanical help with drawing a clear distinction between what is authentically natural and what is not. If you seek further context about the distinction then search out for senses of the terms nature and artificial. Also, in response to the high regard for labor productivity, remember that efficiency can be a force for both creation and destruction.