Biomimicry

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As the ecological designer Sim Van der Ryn mentioned, evolution has been architecture’s best teacher. If the Earth’s history were to be compacted into one year, humanity’s time on the planet would be five and one-half minutes. Evolution had plenty of time to develop the best designs for most every structure on Earth without the need for computers or project management teams. The new specialty in ecological design and architecture called biomimicry relies on using designs invented by Mother Nature for structures for human use.

Biomimicry copies nature in three ways: form and structure, processes, or ecosystem operation. Designers who copy natural forms and structures concentrate on the shapes, sizes, and unique features of natural things and model their designs accordingly. For example, an engineer may design a stronger type of corrugated wall modeled on the corrugation of incredibly strong mollusk shells. Designers who copy processes, by contrast, follow the methods in which nature processes its structures. For example, eco-designers might develop water distribution systems based on the system found in redwood trees or even the human body. Redwoods transport water 350 feet (107 m) from their roots to the topmost upper leaves, and they do this silently, powered only by sunlight. The heart pumps
blood through the cardiovascular system, and yet, as the California ecodesigner Jay Harman pointed out in the San Francisco Chronicle magazine in 2008, “Your cardiovascular system: 60,000 miles [96,561 km] long and no straight pipes, and it’s far more efficient than anything humans have ever dreamt of.” These feats prove to be a significant challenge for ecobuilding designers.

The job of designing structures that mimic entire natural ecosystems presents a challenge even more difficult than mimicking a single structure in nature. A few zero energy houses achieve a facsimile of ecosystems by relying on sunlight for lighting interiors, solar energy for power, and perhaps a small wetland for cleaning wastewaters. Building a more complex
ecosystem facsimile has been much more difficult. In 1991 eight scientists entered an enclosed structure called Biosphere 2 in the Arizona desert. They intended to demonstrate how humans could live in a self-contained unit that would mimic all of the Earth’s nutrient recycling systems. Despite meticulous planning, the residents of Biosphere 2 struggled with
an oxygen-depleted atmosphere caused by an overgrowth of microbes that

The wings of Morpho rhetenor reflect blue light due to nano-structures in the wing, which
contains no pigmentation. The reflected light makes the wings appear blue to the human
eye. The School of Electronics and Computer Science at the University of Southampton,
England, used this butterfly wing structure as a model for nanoscale photonic crystals.
Photonic crystals transmit information as photons or rays of light. (Nano Group, School of
Electronics and Computer Science, University of Southampton)

consumed oxygen and emitted carbon dioxide (CO2). This was the most serious but not the only problem they faced. Eventually, scientists inside and outside Biosphere 2 ended the experiment, knowing they had not mastered the ability to recreate a natural ecosystem.

Engineers may need to replicate nature’s form and function on a small scale before attempting to mimic whole ecosystems. A clamshell offers a good example of the differences that exist between nature and humans regarding form and function. Clamshells have evolved into the perfect size to protect the clam, allow the creature to feed and eliminate waste, and withstand strong forces from waves and tides. The clam wastes no
extra energy building a shell bigger than it needs. By contrast, people often design oversized houses that waste heat and energy and lead to overconsumption of products simply to fill up the space. Nature builds structures

Ecological design endeavors to mimic natural processes in structures used by humans.
Copying an entire natural ecosystem is very difficult, but landscapers have been
successful in re-creating small wetland ecosystems. A wetland like the one pictured
here can clean runoff, act as a rainwater collector and irrigation source, and provide
water for wildlife. (CanadianPond.ca)

perfectly suited for their functions. Sometimes nature makes structures flexible rather than rigid to absorb strong forces—trees that bend with strong winds—and in other instances the structure possesses incredible rigidity and strength—mussel shells that withstand constant pounding by ocean surf. Engineers copy the methods used in nature to increase a structure’s
durability. For example, engineers design skyscrapers and bridges to sway a little in the face of storms as trees yield to winds. Environmental engineers, nevertheless, still have some distance to cover in order to build things as well as nature. The table on page 23 shows the main differences between the characteristics of human-made structures and natural structures.

Ecological design should start with the question, “How would this problem be solved in nature?” Architects and engineers create strength and durability by building with steel and concrete, but nature often takes

an entirely different approach. The design scientist Jay Harman relayed his observations on nature’s ability to combine fragility and strength. “As I was swimming along the [Australian] reef, waves would come and I’d grab hold of seaweed so that I wouldn’t be pulled onto the reef, and the seaweeds would break off, because they’re quite fragile. And yet, time and time again, even in the most violent storms, I noticed these seaweeds wouldn’t break off even with these huge waves coming past, so what’s happening? Well, all these seaweeds were changing their shape to let the force go past.” Some inventions modeled on things in nature include Alexander Graham Bell’s telephone design based on the structure of the middle ear and George de Mestral’s Velcro, which he designed to mimic burrs that stuck to his dog’s coat. The table on page 24 describes additional examples of adaptations from nature.

Nature tends to use simple materials such as silica, calcium carbonate, or keratin (the protein that gives hair its strength), which all require little energy to make. Environmental engineers study not only the composition of natural materials, but also the way nature makes these materials. Designers and engineers take slightly different approaches toward
mimicking nature. Designers use biomimicry to imitate natural designs. Engineers, however, stress the field of biomimetics, which uses engineering principles to build biology-based structures. The chemical engineer 

Robert Cohen of the Massachusetts Institute of Technology explained to National Geographic in 2008 the value of biomimetics, “Looking at pretty structures in nature is not sufficient. What I want to know is, Can we actually transform these structures into an embodiment with true utility in the world?” This of course is the challenge of biomimicry and biomimetics. Harman warned, “It’s like trying to understand the universe. In order to really understand the universe, we sort of have to be outside the universe and look at it from a distance. The best we can hope for is to achieve levels of understanding.” The following sidebar “Abalone Shell—Designed for Strength” describes an instance in which engineers have studied the fine points of a natural structure to learn from it.