It doesn't. Hence the curiosities and concerns about general AI, non-human intelligence, hopefully created by us humans, the first intelligences intelligent enough to design their successor instead of letting a weaker non-intelligent design process such as evolution happen upon it by chance.

The site I linked to has some good introductory material to the related concepts. (http://yudkowsky.net/singularity/intro is short and to the point.) http://singularity.org/research/ lists some important texts to read, and following up on the authors will lead to more. (An author I will also recommend following for his practical pursuits is Ben Goertzel. Lastly, I think this is a good criticism of the Singularity Institute's general mode of operating: http://kruel.co/2012/11/03/what-i-would-like-the-singularity... But you should probably read that one last, if you intend to read anything at all beyond the simple introduction.)