Survival Of The Fittest
This claim exemplifies the naturalistic fallacy -- arguing that the way things are implies how they ought to be. It is like saying that, if someone's arm is broken, it should stay broken. But "is" does not imply "ought." Evolution is descriptive. It tells how things are, not how they should be. http://www.talkorigins.org/indexcc/CA/CA002.html
Humans, being social, improve their fitness through cooperation with other people. Even if survival of the fittest were taken as a basis for morals, it would imply treating other people well.
The phrase 'survival of the fittest' was not even Darwin's. It was urged on him by Wallace, the codiscoverer of natural selection, who hated 'natural selection' because he thought it implied that something was doing the selecting. Darwin coined the term 'natural selection' because had made an analogy with 'artificial selection' as done by breeders, an analogy Wallace hadn't made when he ...