Lets look at
> one popular attempt to ground morality in biology: considering things as
> evolutionarily favored or disfavored. Isn't it an evolutionarily favored
> behavior to wipe out groups that have the maximum variation from one's own
> genes and taking over their slots in the ecosystem. Isn't it also genocide
> and evil?
Let me jump in here. I think there is some confusion about gene behavior individual behavior and species behavior.
The gene does act and always behaves selfishly or it perishes but selfish does not equate with competition. Cooperation may be (and usually is) a better strategy except when comparing allelles (different versions of the same gene). Since genes must act selfiishly there is no such thing as good or evil from the gene's eye view. All sorts of nastiness occurs at the gene level. Maternal diabetes is the result of paternal genes in the placenta trying to get as much energy as possible from the mother and her fighting back. The Y chromosome is small because it is constantly being attacked by genes on the x chromosome so it has become small to hide. Kin selection is a good example of selfish alturistic behavior (One wag said "I would die for two brothers or eight cousins".
At the level of the individual organism (the orthodox level of selection- Mayr et al) organisms can behave altruistically if it benefits them that is improves their level of survival. One would therefore not automatically murder others with different genes. Your own genes wouldn't favor it by necessity. There is an enormous amount of work on this in game theory. Tit for Tat etc. For a good review read Dawkins "The Selfish Gene" or Ridley's "The Origins of Virtue". Basically it turns out that cooperative "good" behavior is favored or competitive "nasty " behavior whenever the parties have to engage in repeated interactions. This has some bearing on other debates happening here in particular the Geneva Convention Arguement. Our military (or at least some members) favors application of the Convention because they want the same protections in future conflicts. In this context it is not surprising that Colin Powell an ex-general favors this approach while Rummy and Chaney! ! who are not military people do not.
At the level of the group things get very tricky. Group selection as a common mechanism was shown by Hamilton and Williams to be a non-starter (individuals who do things for the group die out). In social animals the group can be important if behavior that favors the success of the group directly benefits the individuals. This sort of behavior may be important in one particular bipedal ape.
Species selection does not occur but when two similar species (sibling species or species that occupy the same niche) meet up the better adapted will win.
Within all of this complexity the simple formulas "Wipe out anything not exactly like you" or "Love all strangers as if they were kin" do not work.
