What do a Swiss engineer, a giraffe, and a German pilot traveling at 9G's have in common? The answer lies in a new field of science called biomimicry. Find out more on this episode of the Synapse Science Podcast!
- Action Potentials: https://faculty.washington.edu/chudler/ap.html
- First use of the word 'biomimicry': Merrill, C. L. (1982). Biomimicry of the Dioxygen Active Site in the Copper Proteins Hemocyanin and Cytochrome Oxidase. Rice University.
- Inventor of Velcro (R): http://www.swissinfo.ch/eng/how-a-swiss-invention-hooked-the-world/5653568
- More on Velcro (R): http://www.wipo.int/ipadvantage/en/details.jsp?id=2658
- Mitchell, G., Van Sittert, S. J., & Skinner, J. D. (2009). The structure and function of giraffe jugular vein valves. South African Journal of Wildlife Research, 39(2), 175-180.
- Brøndum, E., Hasenkam, J. M., Secher, N. H., Bertelsen, M. F., Grøndahl, C., Petersen, K. K., ... & Wang, T. (2009). Jugular venous pooling during lowering of the head affects blood pressure of the anesthetized giraffe. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 297(4), R1058-R1065.
- Brondum, E. T., Wang, T., Hasenkam, M., Nygaard, H., Secher, N. H., Petersen, K. K., ... & Aalkjaer, C. (2007). Regulation of blood pressure during head movement in the anaesthetized giraffe. The FASEB Journal, 21(6), A1400.
- G-RAFFE suits made by G-Nius Pte. Ltd (Company Website)
- How Biomimicry is Inspiring Human Innovation (Article, Smithsonian)
- Inventions Inspired by Nature Biomimicry (Slideshow, Bloomberg)
- Vincent, J. F., Bogatyreva, O. A., Bogatyrev, N. R., Bowyer, A., & Pahl, A. K. (2006). Biomimetics: its practice and theory. Journal of the Royal Society Interface, 3(9), 471-482.
- BBC Documentary: Richard Hammond's Miracles of Nature
- "Biomimicry in action" by Janine Benyus (TED talk)
Definition & History
Biomimicry. The very term itself is derived from two ancient Greek words: βίος (bios), life, and μίμησις (mīmēsis), imitation. μίμησις (mīmēsis) itself comes from from μῖμος (mimos), meaning actor. So literally biomimicry is a field involved in imitating life, imitating the models and systems and characteristics of nature in the development of human processes. Biomimicry is observing how nature has managed to solve some of its most intriguing problems and applying those solutions to our own pursuits. Some have called it a new approach to innovation that provides more sustainable solutions to current challenges faced by human industries.
The first traces of biomimicry in action can probably be dated back to good old Leonardo da Vinci in the 15th century. Da Vinci's flying machines were most likely influenced by his avian observations - his sketchbooks contained many sketches of bird flight as well as multiple observations on how birds do what they do so well. Later in 1903, the Wright Brothers were also heavily influenced by the dynamics of pigeon flight, incorporating some of nature's design into the world's first successful heavier-than-air aircraft.
Where does the phrase "biomimicry" actually come from? Sources point to an American biophysicist and overall Renaissance man called Otto Schmitt sometime in the 1950's. If the name sounds familiar, it's because this is the same Schmitt that developed the Schmitt trigger. The Schmitt trigger is an electronic circuit with two stable equilibrium states. When input into the circuit rises above a certain threshold, the circuit output will also increase up to a certain maximum. When the input voltage falls below a certain threshold, the circuit output also decreases, almost all the way down to zero. Does this system sound familiar? If you're a tiny bit familiar with neuroscience, it may seem reminiscent of an action potential mechanism. In fact, Schmitt developed this circuit as a result of his grad student days spent studying the nervous system of squids. He observed this interesting biological phenomenon of nerve propagation, or action potentials, in which the electrical membrane potential of a cell (like a neuron) can rise and fall quickly as the signal travels down the length of the axon. The Schmitt trigger was an attempt to replicate this phenomenon.
Schmitt's views of applying biological knowledge to problems faced in physical sciences and engineering came to be known as biomimetics. Around this same timeframe, the term "bionics" was also coined by a fellow right down the hall (figuratively speaking) called Jack E. Steele. Steele defined "bionics" specifically as, and I quote, "the science of systems which have some function copied from nature, or which represent characteristics of natural systems or their analogues". The term bionic has since been associated more specifically with solving engineering problems using knowledge of how biological systems function. TV programs like The Six Million Dollar Man in 1974 (inspired by Martin Caidin's novel, "Cyborg") later crafted the word "bionic" to mean "the use of electronically operated artificial body parts", largely implying superhuman strength thanks to technological aid. The scientific community largely abandoned the term "bionic" probably as a result of its misinterpretation in the scifi community.
The term "biomimetics" had been floating around quietly the whole time until around 1982, when a spin-off word "biomimicry" was used in the title of a scientific paper on the dioxygen active site in the copper proteins called hemocyanin and cytochrome oxidase. If that kind of thing floats your boat, there'll be a link to the paper in the show notes. Biomimicry was then popularized by Janine Benyus in 1997, when she wrote a book entitled, "Biomimicry: Innovation Inspired by Nature". Benyus is known widely ever since for her work on biomimicry, with her titles including American natural sciences writer, author, President of The Biomimicry Institute, co-founder of Biomimicry Guild, and innovation consultant. In her first 1997 book, she defines biomimicry as, and I quote, "a new science that studies nature's models and then imitates or takes inspiration from these designs and processes to solve human problems". Her approach to biomimicry is mostly focused on its appeal as a method of creating sustainable solutions, not just quick and easy fixes.
The Genius is in the Burdock Plant
Speaking of quick and easy fixes, though, one of the most popular and well known examples of biomimicry can be found on the sneakers of many little kids. Well, the cool kids anyway. Because all the cool kids in elementary school had Velcro sneakers. That's right, Velcro (R) is an imitation of the prickly heads or burrs of a thistle burdock plant. In 1941, Swiss electrical engineer George de Mestral was on a hunting trip in the Alps with his trusty canine companion when he turned around to notice his dog was covered in these little prickly burrs. When he got home and looked at them under the microscope, he realized that the thistle burdock plant burrs had this intricate series of hooks that could easily attach itself to loops on animal fur, socks, clothing, or hair. While this most likely was a great way for the plant to spread its seeds around by hitching a ride on the nearest moving object, the end product for humans had a completely different purpose. In the 1950s, de Mestral had successfully replicated this mechanism using fabric strips and was awarded the patent for what was called the hook and loop fastener. De Mestral named the mechanism velcro, which is actually a portmanteau of the French words velours ("velvet") and crochet ("hook") and also a registered trademark of Velcro Industries B.V.
Just like De Mestral noticed how nature had designed an effective fastening system, a great deal of other astute individuals are beginning to notice similar brushstrokes of genius found in living organisms around the world. And the mechanisms they notice in nature don't just make you the coolest kid on the block...studying how Mother Nature operates could actually help us survive on the way to space.
The Genius is in the Giraffe
To tell this story, we need to travel to the savannas, grasslands, and open woodlands of Africa. Somewhere on these lands, a tall terrestrial mammal lowers its head to take a drink of water. What should happen next should be disastrous, but a moment later, the giraffe, having taken a satisfying sip of water, raises its head back up and continues roaming around the African savanna. Why would such a simple act be disastrous?
Consider this. The heart of a giraffe is much like ours, albeit much larger, but it serves the same function of pumping blood through the body at a certain pressure to ensure that blood reaches all our extremities. Now visualize that incredibly long neck that's characteristic of the giraffe. That's quite a long way to pump blood up to the brain, thus the normal blood pressure of a giraffe is something like twice that of human beings. It's the highest blood pressure of any living being. Once the blood reaches the head of the giraffe, the blood pressure is half that.
So what happens when the giraffe lowers its head to take a drink? Gravity steps in, and it steps in hard. Gravity helps blood to flood down into the giraffe's head, increasing the blood pressure in the brain to dangerous levels. Normally, what happens when you have a closed container and you keep increasing the internal pressure, the whole thing explodes. But giraffe explosions aren't a natural occurrence...thankfully. Childhood trips to the zoo would be a traumatic event. Managing blood flow to the brain and cranial blood pressure requires some additional mechanisms, but for a giraffe, that's no tall order.
Part of the giraffe's secret most likely lies in its complex network of arterioles and small veins that's found in its neck. This network is called the rete mirabile (Latin for "wonderful net"). The rete mirabile helps to reduce the amount of pressure in the giraffe brain's arterial vessels by expanding the venous vessels when the animal lowers its head. Just like if you were squeezing your garden water hose and then let go, the hose would expand and the water pressure would decrease. A similar thing may be going on in giraffes. This would help to attenuate any pressure problems that the giraffe may experience when it lowers its head. In addition to expansion, the rete mirabile also kind of acts like a sponge, containing the extra blood going to the head, resulting in an accumulation of blood. When the giraffe lifts its head back up, this blood can go through to the brain and prevent the giraffe from fainting or getting light-headed on the way up. Some studies also suggest that the jugular vein in the giraffe may also expand when the head is lowered, again allowing for a decrease in pressure in the head. What this means is that the blood vessels of a giraffe have certain elastic qualities, allowing dynamic expansion and contraction to respond to changes in blood volume, induced by the giraffe simply lowering its head.
Outside of their circulatory system, giraffes also have another trick up their incredibly long sleeves. Since the giraffe is such a tall animal (about 5 m or 17 ft on average), the blood vessels located in the long legs of the giraffe are under greater pressure. Think of the giraffe like a fluid column, and you can start to see how the weight of all the blood and fluid inside the giraffe presses down on the legs of the animal. As a solution, the skin around a giraffe's legs (and neck, for that matter) is very tight, kind of like a G-suit worn by fighter pilots to prevent them from fainting due to excessive g-forces. Pilots experience g-forces along the same axis that their spine is in (call it the y-axis, if you like). This causes significant changes in blood pressure along the length of the pilot's body, and when experiencing high vertical g-forces, blood can rush from the brain and pool in the legs. What a G-suit essentially does is apply pressure to the abdomen and the legs, which in turn maintains blood blow to the brain during high acceleration events in the air.
Now the ability to regulate blood pressure and blood flow the way the giraffe does is pretty appealing to fighter pilots and astronauts. Imagine if there was a way to borrow from the giraffe's elegant and complex design to make life easier for human beings placed under high g-force stresses. What you get is something called the G-raffe suit, developed by a company called G-Nius Pte. Ltd. If anything, you have to appreciate their knack for cutting out the first vowel of a word, hyphenating it, and making it look suave and hip. What the G-raffe suit does is help to maintain blood flow throughout the human body under high g-forces. The suit can be worn under a regular flight suit and contains a series of valves and chambers to help prevent blood pooling in certain areas by compressing the body like the giraffe's blood vessels constrict or how the skin around the giraffe's neck and legs are naturally very tight. In a human scenario, this helps keep blood flowing to the brain and prevents pooling of blood in the legs. Without help from a g-suit, the blood leaves the brain and pilots can end up passing out, experiencing vision problems, or even die under long durations of g-force stress. Usually, humans can survive about 5Gs without a special suit on, but with a type of g-suit, even higher g-forces can be tolerated. With the G-raffe suit on, a German pilot who was chosen to test the apparatus was able to make it up to a little past 9G's in the centrifuge without passing out. Gee-whiz, that's a lot of g's. In fact, just to prove his cognitive abilities were 100% a-okay, he then proceeded to take out a Rubik's cube from his flight suit and solve it while experiencing 9 Gs. From the looks on their website, the G-raffe suit may be available for aeronautic companies to purchase and outfit their pilots and perhaps astronauts with in the future. And all that from a simple giraffe. Well, a not so simple giraffe, a highly complex giraffe.
Sound effects used in this episode are from www.freesfx.co.uk.
Music used in this episode (in order of appearance): "Bass Walker" // "Dreamy Flashback" // "Marty Gots A Plan" // "Fast Talkin" // "Artifact" // "Political Ad" // "Cold Funk" // All music tracks are attributed to Kevin MacLeod and are licensed under Creative Commons: By Attribution 3.0 creativecommons.org/licenses/by/3.0/. All audio clips included in the podcast are used for nonprofit, educational purposes.
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