The Google search engine has inspired a new algorithm that can predict which species losses will spark the fastest implosion of a food web, according to the University of Chicago's Stefano Allesina. "The problem of how ecosystems are likely to respond to the loss of species is quite important, particularly in light of how many different ways human activities are resulting in the local extinctions of populations," says the Santa Fe Institute's Jennifer Dunne. The algorithm's functionality is similar to Google's Web-page-ranking tool, PageRank. PageRank quantifies a page's value to searchers depending on the importance of the pages that link to it. However, the Google ranking system assumes that any page might lead to any other page--a concept that is not applicable to food webs. Allesina and Mercedes Pascual of the University of Michigan in Ann Arbor only drew connections between predator and prey. The researchers compared the new algorithm to others by using information from real-world food webs. The algorithm matched results of the standard-bearing genetic algorithm without being computationally intensive.
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