Google Algorithm Predicts When Species Will Go 404, Not Found
Biologists have figured out the most efficient way to destroy an ecosystem — and it’s based on the Google search algorithm.
Scientists have long known that the extinction of key species in a food web can cause collapse of the entire system, but the vast number of interactions between species makes it difficult to guess which animals and plants are the most important. Now, computational biologists have adapted the Google search algorithm, called PageRank, to the problem of predicting ecological collapse, and they’ve created a startlingly accurate model.
“While several previous studies have looked at the robustness of food webs to a variety of sequences of species loss, none of them have come up with a way to identify the most devastating sequence of extinctions,” said food web biologist Jennifer Dunne of the Santa Fe Institute, who was not involved in the research. Using a modified version of PageRank, Dunne said, the researchers were able to identify which species extinctions within a food web would lead to biggest chain-reaction of species death.
“If we can find the way of removing species so that the destruction of the ecosystem is the fastest, it means we’re ranking species by their importance,” said ecologist Stefano Allesina of the University of California, Santa Barbara, who co-authored the paper published Friday in PLoS Computational Biology.
Unlike previous solutions to the coextinction problem, the Google solution takes into account not only the number of connections between species, but also their relative importance. “In PageRank, you’re an important website if important websites point to you,” Allesina said. “We took that idea and reversed it: Species are important if they support important species.”
http://www.wired.com/wiredscience/2009/09/googlefoodwebs/