Sufficiently hostile environmental conditions destroy living things by causing error catastrophes / mutational meltdowns. You have to go in the opposite direction to see constructive, adaptive evolution - which is basically what I was talking about.
If your environment is insufficiently hostile there will be no natural selection at all. Evolution does not have a direction. The life that survives survives the life that does not, does not. That's it. Conditions are favorable for some life and unfavorable for others. There are indeed conditions where few complex, macroscopic life forms will develop-- but that is because in those conditions it is disadvantageous to be complex or macroscopic. If you live next to an underwater steam vent you're probably the kind of thing that likes to live there and won't do well in Monaco.
Re: "Evolution does not have a direction."
My essay about that: http://originoflife.net/direction/
See also, the books "Non-Zero" and "Evolution's Arrow".
In this video, Julian Savulescu from the Uehiro centre for Practical Ethics argues that human beings are "Unfit for the future" - that radical technological advance, liberal democracy and human nature will combine to make the 21st century the century of global catastropes, perpetrated by terrorists and psychopaths, with tools such as engineered viruses. He goes on to argue that enhanced intelligence and a reduced urge to violence and defection in large commons problems could be achieved using science, and may be a way out for humanity.
Skip to 1:30 to avoid the tedious introduction
Genetically enhance humanity or face extinction - PART 1 from Ethics of the New Biosciences on Vimeo.
Genetically enhance humanity or face extinction - PART 2 from Ethics of the New Biosciences on Vimeo.
Well, I have already said something rather like this. Perhaps this really is a good idea, more important, even, than coding a friendly AI? AI timelines where super-smart AI doesn't get invented until 2060+ would leave enough room for human intelligence enhancement to happen and have an effect. When I collected some SIAI volunteers' opinions on this, most thought that there was a very significant chance that super-smart AI will arrive sooner than that, though.
A large portion of the video consists of pointing out the very strong scientific case that our behavior is a result of the way our brains are structured, and that this means that changes in our behavior are the result of changes in the way our brains are wired.