[ccallebs]

> The most important thing to understand about evolution is that natural selection can only work with the existing traits of an organism, the current environment in which the organism exists, and what random changes happen.

I believe most of the time you're right, the changes are random. However, at least one experiment has shown that species can pass adaptive traits to their offspring (called Lamarckian inheritance) [1]. The experiment is intriguing, in that it seems to hint something more is going on than the Darwinian inheritance model.

[1] http://newsroom.cumc.columbia.edu/blog/2014/07/17/effects-of...