For those of us not in the know, what are the models of group evolution you mention?The answer turned out to be too long for a reply, so here it is. DISCLAIMER: I am a complete amateur in this area, so take this synopsis for what it's worth.
Conventional evolution--the "Darwinian Synthesis"--notes that the gene, rather than the individual, is the unit of selection. That is, evolution operates by killing off some genes and replicating others. The organism is simply the vehicle.
However, biologists have long argued about the evolution of certain traits that don't seem to favor the reproductive success--and, hence, the genes--of the individuals who have them. The classic conundrum is altruism. If you jump into a raging river to save a drowning person, you are much more likely to die than if you watch dispassionately from the shore. Yet altruism is a human universal, and has been observed in other species as well. Why have not those genes been eliminated?
One simple answer is group selection. The naive version goes like this: Yes, your genes will perish. But your tribe is stronger because you are willing to do this. Your tribe will cooperate more, save each others' lives, and therefore outcompete other, less-altruistic tribes. This model imagines natural selection operating at the levels of groups: better-adapted groups thrive, worse-adapted groups don't.
This is intuitive. The problem is that the math doesn't seem to support it. The benefit to the group has to be implausibly huge, and the risk tiny, for these genes to survive. The reason is that you're directly competing with people within your group, and compared to them, you, Mr. Altruist, are a total loser. As in, you are dead, rendering your further reproductive success highly doubtful
A somewhat different explanation, which came to prominence in the 1960s and 1970s, is called kin selection, or inclusive selection. Kin selection says, basically, that altruism is disguised selfishness. Your genes are willing to risk themselves to the extent that the victim in the river may have some of those same genes. Thus, most people are very altruistic towards their children; somewhat altruistic towards near relatives; slightly altruistic to distant relatives; and very little altruistic towards complete strangers.
Kin selection is now the orthodoxy among biologists. It has some math to back it up, and some examples that fit the observed data. Edward Wilson himself was originally a prominent supporter.
More recently he's broken with the Church, and has been appropriately vilified therefor. His current argument is that there is a more subtle form of group selection that does meet the mathematical tests, while the math behind kin selection is flawed.
Boiling it down, my understanding of his position is that, just as you can model an individual as a carrier of heteregeneous genes, you can model a group the same way. The unit of selection is still the gene--but if you're talking about a gene that's dispersed through the group, it may make sense to talk about the group collectively "having" some genetic trait.
In a social species, for example, a gene that promotes a feeling of social cohesion may be an individual reproductive advantage; individuals that have it will cooperate to outcompete individuals who don't. At the point where the "cooperation" gene is dispersed through the group, you can sensibly model natural selection at higher levels than the individual.
Obviously, you should not rely on a dilettante engineer for your biology homework. I don't know enough about the subject to have an opinion one way or the other, although it does seem to me that both Wilson and his opponents--especially Richard Dawkins--are behaving somewhat childishly. Here is what seems to me to be an in-depth "middle-ground" position, if you're curious.