Evolution has fascinated me ever since I learned about it. I spent some time thinking about it, what it really is, what its purpose is, what its limitations are. As many people, initially I anthropomorphized evolution, almost making it into something by itself intelligent, purposeful. I quickly realized that evolution is nothing else than a statistical process related to survival bias -- it's a manifestation of the fact that over time, as species compete for resources, the random mutations that happen to improve the odds of one species surviving will become dominant. We, the outside observers, will see this as the betterment of species, but evolution is nothing more than an epiphenomenon.
Evolution becomes interesting when we consider the role humans play in it. People believe that the shape of our hands enabled us to create and use tools which had a tremendous evolutionary advantage (these tools were a de facto extension of our bodies; they could be produced, used and discarded well within the lifetime of an individual). This ability led to an emergence of intelligence, which ultimately obviated the need for mutations: instead of waiting for a random mutation to take place over many generations to adapt to changing conditions, humans can adapt much faster through being smart. If a new Ice Age hit the planet, instead of waiting for mutations to occur that would offer some protection from the cold (such as thick fur), humans can simply leverage their ability to use tools to build dwellings that protect them from the cold, or skin animals to wear their fur.
In a way, in an age of intelligent creatures, evolution is obsolete -- i.e. humans will no longer need to evolve since the mutations no longer carry significant comparative advantage. At a risk of making evolution into something it's not again, one can say that evolution made itself obsolete, since the emergence of intelligence happened through an evolutionary process (whether intelligence is a necessary step in the evolution of species is an entirely separate and fascinating question; I'll probably come back to it at some point).
As the epiphenomenon of evolution has been replaced by the phenomenon of intelligence, the prerogative of survival has been replaced by the mission of betterment. This "betterment" is simply an extension of the work of our tool-building ancestors, who perceived problems and use the tools to solve them. The creation of more elaborate and abstract tools allowed humans to solve more and more fundamental problems that they face, an, in an extreme, also prevent future problems (so, in my view, string theory is no different than a sharpened stick that our ancestors used to kill animals). And as intelligent creatures attempt to achieve progress at an ever-increasingly faster rate, they begin to reach for more and more fundamental devices, eventually imitating nature itself. The next step for intelligent creates, in my view, will be the mastery of genetic engineering -- the human body being the kind of ultimate tool at his disposal (at which point mutations will be replaced by direct changes to the human DNA in order to fulfill specific goals). Eventually humans will breach the final limitation, that of the biological medium. In that final breakthrough, what is natural will be replaced by what is conceivable (a very primitive example of this is artificial intelligence).
As we see, more primitive (and constrained) processes are replaced by more advanced ones (either those that take less time to effect a change, or those that break down more limitations). In a way, then, we're dealing with an epiphenomenon of meta-evolution, the "survival" of large-scale processes observed in species.
It's easy to misunderstand evolution. My mentor said that evolution as the natural move toward better should be understood as the greatest single force in the universe. He also said that outcomes consistent with natural laws ("good" outcomes) will likely lead to rewards and this is why we should all be striving for achieving outcomes contributing to evolution (as the latter is the fundamental natural law). I think it's a somewhat superficial understanding of evolution as something special -- an instance of the aforementioned anthropomorphizing of evolution. There is nothing special about evolution other than it being an example of how some processes in the Universe that tend to increase entropy can exhibit patterns consistent with evolution.