November 1, 2009 | David F. Coppedge

To Advance Science, Imitate Nature

Biomimetics – the imitation of nature – continues to be one of the hottest areas in science.  Here are a few of the latest findings coming from the world of living creatures.

  1. Fish robot:  National Geographic News shows a photo of the latest thing in underwater robotics: a robotic submarine modeled after the Amazonian knifefish.  In particular, the inventors at the University of Bath noticed that the knifefish “keeps its body rigid to sense electric currents in the water.”  Their “gymnobot” stays rigid but lets its rear fin propel it through the water.
        PhysOrg reported that engineers at Michigan State are also modeling their underwater robots after fish.  They could patrol underwater for months, providing information on water quality, oxygen, algae and bacteria levels, and other data.  “Fish are very efficient,” explained Xiaobo Tan, an assistant professor of electrical and computer engineering.  “They can perform very efficient locomotion and maneuvering in the water.”  The 9-inch robots use fins made of electro-active polymers to change shape and swim, and use GPS to navigate precisely.  The designers didn’t say, though, what they will do if their robots get swallowed by a bigger fish.
  2. Spider suture:  New Scientist had more to say about the efforts to reproduce spider glue as a biodegradable suture for surgery (see 10/24/2009, bullet 2).
  3. Shrimp DVDs:  “Mantis Shrimp Eyes Could Show Way To Better DVD And CD players,” announced Science Daily.  That’s because the eyes of this lowly shrimp sense 12 colors and can distinguish between different forms of polarized light.  Dr. Nicholas Roberts (U of Bristol) said, “Our work reveals for the first time the unique design and mechanism of the quarter-wave plate in the mantis shrimp’s eye.  It really is exceptionalout-performing anything we humans have so far been able to create.”  He also remarked emphatically, “What’s particularly exciting is how beautifully simple it is.  This natural mechanism, comprised of cell membranes rolled into tubes, completely outperforms synthetic designs.”  By using liquid crystals “chemically engineered to mimic the properties of the cells in the mantis shrimp’s eye,” the process “could inspire the next generation of DVD and CD players.”  The same U of Bristol press release was printed by PhysOrg.
  4. Flipper power:  Researchers at Duke University are figuring out the reasons for differences in the flippers of dolphins, reported Live Science.  It appears that form follows function.  Some dolphins swim slowly in shallow water; some swim fast in deep water.  The team is performing the “first-ever comparative hydrodynamic analysis of cetacean flippers.”  All dolphins have the backward swept fins we know from surfboards and behave “comparable to engineered hydrofoils.”  The fast species have sharply backward swept edges and exhibit “the same unusually advanced lift properties as triangular-winged aircraft, such as the Concorde and some military planes,” while the slower river dolphins have “relatively broad triangular flippers that aid maneuvering in complex river�floodplain systems.”  While the short article did not mention biomimetics, it is clear that understanding the biological designs will have applications for improving aircraft, ships and submarines — maybe surfboards, too.
  5. Wet cell battery:  PhysOrg reported on attempts by Yale scientists to make tiny batteries, imitating the ion channels of living cells.  It’s a “daunting task” to understand the function of each molecule in a living cell membrane, but they’ve had some initial success with a very simplified bilayer system.  “Building synthetic versions of complex real cells—such as those that enable an electric eel to zap its prey – is far too difficult a task for now,” one of the researchers said.  One benefit of this kind of biomimetic research is that it feeds back into better understanding of living cells: “researchers can study cellular machinery one manageable piece at a time.”

In the fish-robot entry above, National Geographic made a comment that could be applied to all biomimetic efforts: “Researchers worldwide are developing robots that look and act like aquatic creatures.  That’s because biomimetic gadgets—bots that take inspiration from nature—are often more efficient than their clunkier counterparts.”

In the mantis shrimp story, Science Daily speculated about the evolution of the remarkable eye.  “Exactly why the mantis shrimp needs such exquisite sensitivity to circularly polarized light isn’t clear.”  Was it for sex, or for avoiding predators?  “If this mechanism in the mantis shrimp provides an evolutionary advantage, it would be easily selected for as it only requires small changes to existing properties of the cell in the eye.”  They need to read Michael Behe’s book The Edge of Evolution.  Strange that a blind process produced a system that seeing scientists cannot imitate.
    That was the only entry of the five that had anything to say about evolution.  As usual, it was not germane to the research.  It was only an oversimplified tale tacked on by someone willfully ignoring the issues involved in trying to tinker one’s way up to complex specified design.  In productive science labs, Tinker Bell need not apply.

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