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Natural selection isn’t nearly enough to explain how life created so many innovations so fast. Fortunately for us, writes SFI External Professor Andreas Wagner in a new book, Nature had something else up her sleeve: robustness.

Even in organisms with relatively few genes, the number of possible combinations of those genes is unimaginably enormous — many, many orders of magnitude greater than the number of hydrogen atoms in the Universe. Even 3.7 billions years isn’t enough to search all those possibilities at random and find all the forms of life we have today.

In Arrival of the Fittest: Solving Evolution's Greatest Puzzle (Current Hardcover , October 2, 2014), Wagner shows how robustness, long a subject of interest at SFI, helped solve the problem. Metabolic systems, protein interactions, and gene regulation networks share a particular kind of robustness: even drastic changes to the underlying structure leaves their operations unchanged. For example, the complex of chemical reactions that metabolize glucose in E. coli can overlap by as little as 20 percent and still function perfectly well.

Read a review of Wagner's book by Mark Pagel in Nature (October 1, 2014)

At the same time, very small genetic changes can radically alter the phenotype. Some such alterations portend certain death, but a few lead to powerful new innovations: the ability to fly, for example, or the first light-sensitive cells eventually leading to photosynthesis. Searching all the genetic possibilities at random would take forever, but a species — with all the same functions, but widely varying genes — can search millions of genetic options all at once, dramatically increasing evolution’s efficiency.

Robustness itself is a response to environmental complexity, Wagner argues. To withstand heat, cold, moisture, and dryness, living things developed a modular toolset of molecules such as amino acids, which combined in complex ways to produce a range of innovations in response to any given problem.

Technology innovators might take a lesson from that strategy, he suggests. While we often prefer simple solutions, Nature has found that complexity leads to robustness, and robustness leads to innovation.

More about Arrival of the Fittest 

Read a review of Wagner's book in Kirkus Reviews (October 1, 2014)

Read a Q&A with Wagner in the World Science Festival's "Smart Reads" (September 30, 2014)

Read a review of Wagner's book on Paleolibrarian (October 1, 2014)

Read a review of Wagner's book on Patheos blog "The Friendly Atheist" (October 2, 2014)

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