Explanation for power law in biology

Network biology is an emerging field that incorporates several of the themes discussed in class. In this review (http://www.nature.com/nrg/journal/v5/n2/full/nrg1272.html) Barabasi and Oltvai (a former NU professor) discuss the pervasiveness of the power law in biological networks. In short, they propose the reason for its ubiquity is because (1) new nodes join the system over time and (2) nodes prefer to link to nodes that already have many links. This makes sense because the more connections a node has, the higher the probability a new node will connect to it. Check out their review for more, they do some cool work.