Cooperation and multilevel selection

A few days ago I introduced how higher levels of selection could occur via a "toy" example. Obviously it wasn't realistic, and as RPM pointed out a real population is not open ended in its growth potential. I simply wanted to allude to the seeds of how Simpson's Paradox might occur, where population structure is needed to explain overall trends. Now I'm going to dive into a somewhat more complicated model, one which Martin Nowak published last year in PNAS, Evolution of cooperation by multilevel selection. The paper is free, so if this post piques your interest I recommend you dive straight into the paper. I've blogged Nowak's Evolutionary Dynamics, a recent book which gives accessible summaries of his body of work within mathematical biology, and am comfortable with his formalisms. So that explains my choice of this particular paper (though I plan to hit a few others and perhaps ...