Animals Overcome Limitations of Physics
The limits of human engineering have been overcome by animals in surprising ways worth imitating.
Cochlea secrets improve sound reception: Why does the cochlea in the mammalian inner ear have two fluid-filled chambers? Prof. Marcel van der Heijden at Erasmus Medical Center, University Medical Center, Rotterdam, wanted to know. He found that the leading “resonance theory” is wrong; experiments have shown that lab imitations can either get frequency tuning or amplification, but not both. Van der Heijden’s new model based on the cochlea’s two-chamber design can carry waves and do spectral analysis simultaneously, because it “displays strong structural and behavioral similarities to the cochlea.” The living cochlea, though, still excels in its ability to perform “multiband dynamic range compression” and “automatic gain control,” among other advanced features. The new work relies on the theory of “optical coherence tomography.” The article goes into some detail about how the cochlea works.
Shrimp sees cancer: The mantis shrimp has been a frequent focus of engineering interest for its amazing eyes (1/29/14, 3/31/08 #5) and claws (7/06/14). Now, an interdisciplinary team at the University of Queensland believes that sensors modeled on the mantis shrimp eye could detect cancer. PhysOrg says, “Mantis shrimp eyes are inspiring the design of new cameras that can detect a variety of cancers and visualise brain activity.” That’s because “the shrimp’s compound eyes are superbly tuned to detect polarised light, providing a streamlined framework for technology to mimic.”
Butterfly photonics: One of the early biomimetic stories concerned “photonic crystals” found on insect wings and bird feathers – structures that manipulate light without pigment (1/29/03). PNAS just published a paper by Harvard scientists who made “Bioinspired micrograting arrays mimicking the reverse color diffraction elements evolved by the butterfly Pierella luna.” Although evolution was on the lips of the UK team (“In the course of evolution, many organisms have developed unique light manipulation strategies…”), it was not in their techniques. Those involved intelligent design: “Exploiting and improving the butterfly’s strategy, we create photonic materials that increase our basic understanding of the optical interplay of hierarchical structures and provide a platform for the development of novel photonic devices.” Among them, Live Science reported, could be “counterfeit-proof tech” because the material is “difficult to create”.
Beetle paint: A related article on PhysOrg discusses a more “natural route” to photonics being investigated across the pond by Oxford scientists: “Researchers take cells from chrysalis and use them to grow butterfly wings in the lab.” Judging from the durability of these photonic crystals in fossils, it should be possible to create long-lasting colored surfaces that could be painted on. “They point out that such materials would never fade, noting that similar beetles from millions of years ago that have been unearthed, still have the same colors that had when alive,” the article concludes. “They also note that they believe what they’ve discovered is only the beginning—they envision a host of products grown from a wide variety of cells from fish, peacocks, and many types of insects.”
Membrane tech: A researcher at the University of Leeds sees “endless possibilities for bio-nanotechnology,” says PhysOrg, thanks to the imitation of lipid membranes that cells use to enclose their systems. That “thin skin” that surrounds biological cells “can be applied to synthetic surfaces,” also mimicking the active transport cells use to control what goes in and out. The university is using nano-lithography and atomic force microscopy in its attempts, “with high precision, to create novel hybrid bio-electronic devices.”
Dolphin sonar: A physical limitation that challenged man-made sonar systems has been overcome by imitating dolphins. PhysOrg headlined its story, “Dolphin-inspired sonar overcomes size-wavelength limitation.” That limitation arises when the size of the sonar arrays is much larger than the wavelength. The article attributes mastery of sonar to evolution, winning an “Amazing” award as well as “Stupid Evolution Quote of the Week” –
While this problem plagues man-made sonar, Yangtze finless porpoises don’t seem to have the same limitation. Through millions of years of evolution and natural selection, the animal has developed a relatively small head (compared to man-made sonar) that can manipulate acoustic waves into a beam with high directivity. Porpoises and dolphins use these highly efficient biosonars for foraging, avoiding predators, and group coordination. Studies have shown that, despite serious vision degradation in water, dolphins can locate centimeter-sized objects 100 meters away using echolocation.
Don’t forget us plants: A clumsy-looking electric “plant” named PLANTOID begins an article on Science Daily about “Robotic solutions inspired by plants.” The prototype in the picture has “a 3D-printed ‘trunk‘, ‘leaves‘ that sense the environment and ‘roots‘ that grow and change direction.” Why would a robot designer make like a leaf? “Humans naturally understand problems and solutions from an animal’s perspective, tending to see plants as passive organisms that don’t ‘do’ much of anything, but plants do move, and they sense, and they do so in extremely efficient ways.” Because “plants are very efficient in terms of their energy consumption during motion,” using no muscles, your future surgery could benefit from this research.
The shrilk joy of it all: New Scientist has an updated account of Shrilk, a new bio-friendly replacement for plastic made from spider silk and shrimp exoskeleton. This might be a far better replacement than the current material that Salee Adee says is still inhabiting a landfill somewhere with your baby diapers. That old polyethylene plastic may last a few centuries more. A photo shows what shrilk looks like: “a tough, biodegradable replacement for world-choking plastics.”
Nano-mold: Harvard’s Wyss Center for Biologically Inspired Engineering achieved a “significant breakthrough” in nano-technology. PhysOrg says they have constructed tiny structures made from a familiar biological molecule: DNA. This ability allows them to “form tiny 3D metal nanoparticles in prescribed shapes and dimensions using DNA, Nature’s building block, as a construction mold.” A sheet of paper is 100,000 nanometers thick; these DNA molds are as small as 25 nanometers. “The properties of DNA that allow it to self assemble and encode the building blocks of life have been harnessed, re-purposed and re-imagined for the nano-manufacturing of inorganic materials,” one of the team members said. “This capability should open up entirely new strategies for fields ranging from computer miniaturization to energy and pathogen detection.”
Pitcher this: The Wyss Center also came up with a bio-inspired material for coating medical devices, PhysOrg said. The material, called SLIPS, repels blood, prevents clotting, and resists bacterial biofilms. Where’d they get the idea? “Inspired by the slippery surface of the carnivorous pitcher plant, which enables the plant to capture insects, SLIPS repels nearly any material it contacts.”
Design is everywhere from Atlanta to Zoo: Georgia Tech’s Center for Biologically Inspired Design has created an iPhone app called ZooScape to raise public awareness about biomimetics and to encourage conservation of the animals that have inspired new technologies. Though usable anywhere, the app becomes interactive at the Atlanta Zoo, where visitors can interact with the lessons in physics coming from animal inspiration. PhysOrg has a short video clip where Marc Weissburg, professor of Biology at Georgia Tech, says, with feeling, “Animals are really amazing in the things that they do, and we learn so much from them, that there’s actually not one that I don’t look at and say, ‘Wow, that’s really cool!’” The clip gives an example: flamingoes have a water filter in their beaks that we don’t fully understand, but it might help us improve water faucets some day. Joe Mendelson, adjunct professor and herpetologist at the zoo, echoed Weissburg’s sentiments. “There’s so much we have learned and still have to learn about animals,” he said. “They’re experts at navigating their environments successfully, and it turns out that sometimes all we have to do to improve our own systems and efficiency is to sit back and watch them do what they already do so well.”
Read how Evolution News & Views responded to the Darwinians’ efforts to insert themselves into biomimetics where they don’t belong, trying to make themselves look relevant to the Design Revolution.