Evolution is much more complicated than "survival of the fittest." That certain genetic tendencies are selected for and passed down through the generations is obvious to anyone who bothers to look at the world around them. Any reasonably intelligent person who has thought about this should not disagree.
The difficult point is exactly how new species arise, and how often it should happen from chance. The exact process(es) are AFAIK not completely understood. Even so, I personally can't understand how all animals could be so extraordinarily similar if they were not directly related.
In terms of modern human life, darwinism obviously doesn't apply in its usual sense anymore. We take care of those would have never survived, etc. I think this is good to a point - intelligence is now more important than physical strength - yet modern medicine is I think getting close to seriously degrading our intrinsic health.
At the same time, we are still a product of our past. We are not wired to be attracted to modern traits. Nerds can hardly get laid, yet they shape our future
