http://www.wired.com/wiredscience/2009/02/homogecene/The small-world phenomenon, which this class covered in the context of social networks, can also be seen in the world of biology these days.The above article discusses how improvements in transportation methods have brought the disparate regions of the world into a more tightly connected network. In the past, before mechanized travel, movement from one region to another was bounded by the speed at which an organism could move on ones feet. Now, however, an ocean-liner can cross the seas in days; a plane can do so in hours. As a result, organisms can travel to totally alien areas relatively easy, a problem that has gained significant attention from biologists in recent years.This article explains how the problem is particularly pronounced in the great lakes region, where, even though only one of the ports there, Montreal, is a big part of the global shipping network, the network within the the lakes region is very “integrated and dense.” The result is something akin to the small-world effect. In social networks, most people have a concentrated network of friends, where most people are pretty similar and all know one another - the effect of homiphily. However, while most edges run through this dense cluster, some edges stretch far beyond to other clusters of friends; such edges are the ultimate catalyst of the small-world phenomenon. Applying this concept to the article above, and you can see the parallels. Montral is the only major node on the global shipping network, but because the Great Lakes shipping network is so dense, even a remote port in the farthest removed part of the great lakes is just a few steps removed from the larger global shipping network. (”The average Great Lakes port … is only an average of two degrees of separation from 80 percent of the ports in the world.”)This has resulted in a fairly easy time for organisms in transplanting from one region to another, a serious challenge to the world in the future.