MSGID: 1:317/3 6466fb61   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Perfection: The Enemy of Evolution    
    Freedom to miss the optimal mark opens a wide range of new designs over   
   time    
      
     Date:   
         May 18, 2023   
     Source:   
         Duke University   
     Summary:   
         Evolution is a sequence of design changes happening on their own in   
         a discernible direction; it never weds itself to a single point on   
         a drawing board. An evolving system or animal is free to simply go   
         with what works. Not so much that its performance suffers greatly,   
         but enough that it opens access to other options near the so-called   
         optimal design.   
      
         With scientists often looking to nature for clues to solve   
         challenges, they should also free to miss the optimal mark and   
         open a wider design space over time.   
      
      
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   FULL STORY   
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   Scientists are often trained to seek out the absolute best solution to a   
   given problem. On a chalk board, this might look something like drawing   
   a graph to find a function's minimum or maximum point. When designing a   
   turbojet engine, it might mean tweaking the rotor blades' angles a tiny   
   degree to achieve a tenth of a percent increase in efficiency.   
      
   Adrian Bejan, the J.A. Jones Distinguished Professor of Mechanical   
   Engineering at Duke University, was busy demonstrating the former for a   
   class full of students when a thought struck him: this is not how nature   
   operates. Evolution is a sequence of design changes happening on their   
   own in a discernible direction; it never weds itself to a single point on   
   a drawing board. An evolving system or animal is free to simply go with   
   what works. Not so much that its performance suffers greatly, but enough   
   that it opens access to other options near the so-called optimal design.   
      
   With science often looking to nature for clues to solve challenges, Bejan   
   wondered if he might look the opposite way, to predict nature before   
   looking at it. If problem solvers and builders were free to miss the   
   absolute highest mark, how much greater might be the range of designs they   
   consider plausible?  That's the question that Bejan posits in a new paper   
   published online May 16 in the journal Biosystems. Using two relatively   
   simple examples -- walkways ferrying passengers off a train and a bird   
   flapping its wings -- he discovers that the answer is, "quite a lot."   
   "In engineering, design, theater, architecture or even the organization   
   of this university, any form of design benefits from the ability to make   
   good but imperfect decisions and the freedom to move on and contemplate   
   other opportunities for improvement," Bejan said. "If one is wedded   
   to the idea of the absolute best, nothing new will ever be created."   
   In the paper, Bejan first looks at the example of passengers arriving   
   by train and walking across a room with many exit points. With the total   
   area of the room remaining constant but the length and width of the room   
   free to change, he solves for the optimal shape of the room to get all   
   passengers where they're going the quickest. With the solution equations   
   in hand, he shows that providing even 1% wiggle room for imperfection   
   away from the best performance opens the design space by 28%.   
      
   In his second example, Bejan looks at the flapping motion of birds   
   at nearly constant altitude and speed. Considering the various forces   
   involved -- drag during gliding, lift created by wing size, speed and   
   body size, among others - - he formulates an equation for the rhythm of   
   wings needed to maintain constant speed with minimum effort. While an   
   optimal answer does exist, Bejan once again shows that allowing for just   
   1% imperfection above the theoretical minimum effort opens the design   
   space by 20%.   
      
   Bejan says that he chose these examples because they involved changing   
   only a single variable, a single degree of freedom -- the shape for a   
   room or the flapping rhythm for a wing. In more complex examples that   
   involve many variables, these tiny tolerances for imperfection create   
   an even wider range of "good enough" solutions.   
      
   The lesson learned is that science now has a predictive idea of how   
   nature works. By focusing less on finding absolute optimal designs,   
   researchers may use the freedom to iteratively move toward entirely new   
   design concepts that wouldn't otherwise have been within their sight. It   
   also gives designs, methods and entire fields of study the ability to   
   adapt to a changing world.   
      
   "The doctrine of chasing the best design is not helpful," Bejan said. "The   
   teaching of science should go hand-in-hand with the freedom to take a   
   shot, hit the vicinity of the mark and move on. The end goal isn't just   
   to hit a bullseye, but to keep more arrows in your quiver to keep taking   
   shots over a long period of time."  This work was supported by a grant   
   from CaptiveAire Systems.   
      
       * RELATED_TOPICS   
             o Plants_&_Animals   
                   # Evolutionary_Biology # Birds # Nature   
             o Earth_&_Climate   
                   # Sustainability # Earth_Science # Weather   
             o Fossils_&_Ruins   
                   # Evolution # Human_Evolution # Early_Birds   
       * RELATED_TERMS   
             o Hurricane_proof_building o Earth_science   
             o Rotifer o Ionosphere o Weather_forecasting o   
             The_evolution_of_human_intelligence o Convergent_evolution   
             o Parallel_evolution   
      
   ==========================================================================   
   Story Source: Materials provided by Duke_University. Original written   
   by Ken Kingery. Note: Content may be edited for style and length.   
      
      
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   Journal Reference:   
      1. Adrian Bejan. Perfection is the enemy of evolution. Biosystems,   
      2023;   
         229: 104917 DOI: 10.1016/j.biosystems.2023.104917   
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   Link to news story:   
   https://www.sciencedaily.com/releases/2023/05/230518172034.htm   
      
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