Thanks for you comments guys. I think the bottom line was nicely summarized by crashfrog:
There's no evolutionary drive towards complexity. Certain organisms evolved in complex ways as adaptation to environment, but complexity isn't the only way to adapt; it probably isn't even the best way.
So for me the conclusion is: more complex != more evolved
I do not think as evolution as a one-brached three with humans on top (with their little crown), although that's a common mistake among many pleople (myself included perhaps). Showing that picture and telling me (or anybody else) that that's the way I probably think is kind of rude. It's ok to be aggresive when you try to make a point but don't ridicule ignorance.
Anyways, perhaps a related question then is how two (new?) species can coexist? Let me try to explain. When a mutation occurs and a new species appears by natural selection, doesn't the predecesor ceases to exist after a certain time? How is it possible then to have branching in the tree of evolution?
Edited by ircarrascal, : No reason given.