A constant worry in the environmental front of synthetic biology is its influence on natural biodiversity and natural systems in general. Synthetic biology products are human-made things, no more natural than buildings, radio, or television. If this is the case, the question about environment is not solely related to synthetic biology but engineering as a whole. Human constructions - buildings, roads, night lights, irrigation, dams, etc. - have probably affected natural systems significantly. Synthetic biology is another item on this long list; perhaps humans were much less careful about natural systems when they first started engineering buildings or dams. After witnessing the slow decrease of natural landscape, perhaps humans have become more cautious about consequences of engineered products. The question on how to safeguard natural systems from engineered biological systems is perhaps a starting point to the question about how to safeguard natural systems against any engineered system.