There are two examples in this article which are in order to show the nature does not behave in a simple linear way. The invasion of spotted knapweed illustrates that not only the lacking of enemies caused a species flourish, but the microbes in soil also work. That is the complexity of nature system. The other example is reducing fishing would let the fish stocks increase, but indirectly, as a result, it would cause the numbers of some other seabirds decrease. The two examples make out a principle that the nature is an interacted system, and more complex than we could think. So perhaps our motive is good, but if we overlooked the complexity of a system, we may have the opposite results which we don’t want to get.

So for other situations. We can always learn from nature. When we make an environmental planning of a city, or establish standards of the concentration of discharge, we should think about all the possibilities. Some scientists commit themselves to make grey models, which is nonlinear models. I think this is similar with the ways in which nature behave.

I have heard another try: in the last century, some scientists built an experiment base called “Biosphere Ⅱ” in order to study how to set a self-support ecosystem in Mars in the future. There are soil, water source, air and multiplicate plants, animals and microbes in the base. It simulated the earth environment in a hermetic condiction., scientists hope it could provide enough food、ample water and air, which eight researchers could rely on to sustain their lives for two years. However, the fact was widely divergent from the expects. In Jan. 1993, after the researchers had moved in for about one year, the environment quality in the Biosphere Ⅱfell on the level that is not suitable for men to live and work. The concentration of oxygen was lower and lower, while the concentration of carbon dioxide is increasing, atmosphere growing acidification as well as the sea, and most of the vertebrates lost their lives. All that means the experiment was a case of crabs.

This experiment shows that although technology has developed to a high level, it is still impossible to realize a man-made ecosystem. There is no doubt that the complexity of nature is a crucial reason. All kinds of biology and abiology react to each other, they control each other and sometimes work together. This interaction mechanism keep the ecosystem in homeostasis. The earth developed its own function during the far-flung evolution. So far our human beings has known all about the interrelationship of the world biology and abiology. We couldn’t make another earth , and if we want to survive , we have to do our best to ensure the ecosphere be in its own function state.

In my opinion, the nature always teaches us, and we should be good students to nature. There is a long way for us to know all about how nature works , about its complexity. Before we master all the mechanism which works on nature we have to keep it in its natural way.

YanYan
06.9.20