(Article "Social darwinism")

Moral Relativism
If evolution is true, there is no God to set any standards of behavior. Biblical concepts then become relics of the past, and there is no right or wrong, no such thing as immorality (“If it’s right for you then its okay”). It’s now considered “immoral” to restrict the “rights” of those wanting to practice premarital sex, adultery, homosexuality, etc. Since humans are just animals that are a little higher on the evolutionary scale, and animals do these things, then what’s wrong with doing them?
The overall result has been a general lowering of standards of behavior and expectations, even in the Christian community. The entertainment industry is a prime example. People take for granted today TV programs, movies, video games, music that would have caused outrage in previous generations.

Woe to those who call evil good and good evil, who put darkness for light and light for darkness, who put bitter for sweet and sweet for bitter. Woe to those who are wise in their own eyes and clever in their own sight. Isaiah 5:20-21

The Devaluation of Human Life
Abortion views the fetus is not really human yet, but still going through the early stages of evolution, abortion is okay—you’re not really killing a human being. In conjunction with abortion, euthanasia is a practice can be justified on the grounds of moral relativism ("what’s right for me is my choice") as discussed above. God’s will is usually left out of the picture.
Evolutionism provides the same basis for discarding or ignoring moral values as Epicureanism did with the ancient Greeks. Epicureans wanted freedom to indulge in every pleasure without consequence: "Eat, drink, & be merry, for tomorrow we die." Many evolutionists also seek unbridled freedom in every area. Evolution justifies freedom from morality, using science to avoid consequences such as pregnancy, STDs, etc. The only remaining obstacle is Christianity.