PageRank to Explain The World

This class is all about how and why certain things link together. That is the whole idea of networks. As we learned about this past week, PageRank is an algorithm used to establish how “important” a web page or a link is based on the number of links or citations it other pages have to it. The idea of PageRank, though complicated, is fairly intuitive. PageRank, after being in this class for half of a semester really illustrates the strength of networks in my opinion.

A big issue today is the environment, and a part of that is ecosystems and how all different species and life forms are interconnected. Obviously, it is important to understand how these connections work and the strength of any given connection. For instance, if one species goes extinct, or if something were to happen to a species’ natural habitat, this does not only affect the given species, but every other subsequent one that relies on or utilizes the species in question in any way.

An article, published by the New York Times in 2009, cites the research of Stefano Allesina and Mercedes Pascual in their attempt to study the networks of food webs. Instead of using previously established extinction models, Allesina and Pascual adopted the PageRank algorithm and found that it was more effective at “identifying which species’ extinction would cause the greatest number of other species in the food web also to go extinct.” This is a huge step in not only ecosystem and species extinction studies but also in the world. Since network theory is everywhere, the fact that the PageRank algorithm can be applied to the study of species’ interactions means that there may be no limit to what the PageRank model can be used for with the right alterations.

 

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One thought on “PageRank to Explain The World”

  1. This is a very interesting read, kind of impressive to see an algorithm that is used for the internet that can be used to explain why animals go extinct. The two subjects just seem so far apart that it would be impossible to relate them, but obviously its fairly easy. I never thought about the page rank algorithm and dinosaurs in the same context but now it is easy to see the connection. Not too long ago I was watching the history channel and a program on the extinction of dinosaurs was the main topic. In large, if you asked the general public what killed the dinosaurs off? The most common responses are changes in the habitat (ice ages, fluctuating temperatures etc.) and the “giant meteor” explanation. The central focus of the program was to introduce a reason for extinction that was more closely related to this blog post, their extinction was due to network failures. By network failures I mean changes in the habitat that may have caused the eradication of food sources that caused them to essentially starve to death. The explanation was that the rapid temperature fluctuations didn’t necessarily bother the dinosaurs dramatically, but it effected the environment enough to start a chain-reaction of extinction within the feeding network. For instance, spring and summer seasons began to shorten and the cold winter months became longer, this started to kill off vegetation and plant life that were essential to the herbivores. Since food started to become scarce because of the cold, herbivores started to starve to death and die off. Naturally this caused and issue for the carnivores, which began to die off because of the lack of prey animals to feed on. So the network failure began with plant life, expanded to the dinosaurs that ate the plant life, which in turn expanded to the dinosaurs that didn’t even eat plants, but ate the dinosaurs that ate the plants. Essentially the meteor was just the “nail in the coffin” that put the finishing touch on an already rapidly depleting population of dinosaurs, and it was their network that triggered their extinction rather than the meteor.

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