If you are like most people, you probably haven’t devoted much thought to earwax, unless it relates to the safest way to clean it out of your ears.
But earwax is worth thinking about, because it is a remarkable substance with extraordinary properties, as recent work by engineers from Georgia Institute of Technology (GIT) attests.1 In fact, the GIT researchers think that they can use their new insight about earwax to develop specialized filters for electronic devices that must perform in dusty environments.
By using earwax as an inspiration for new technology, these researchers have unwittingly provided more evidence for intelligent design, while at the same time raising a powerful challenge to the evolutionary explanation for the history and the design of life.
What Is Earwax?
This substance is an eclectic mixture of fatty acids, fatty alcohols, cholesterol, and squalene formed from secretions of the sebaceous and the ceruminous glands that line the outer portion of the ear canal. Earwax also consists of shed epithelial cells and hair.
Earwax is produced by all mammals, including humans. Two different types of earwax are found in humans, referred to as wet and dry. Honey brown in color, wet earwax contains a higher concentration of lipids and pigments than dry earwax. A single genetic change converts wet earwax (which is the genetically dominant form) into dry earwax (the genetically recessive form), which is gray and flaky.
The type of earwax a person has reflects their ancestry, with people of African and European descent having the wet variety and Asian and Native American people groups having dry earwax. Anthropologists have noted a correlation between earwax type and body odor. People with wet earwax tend to be more odiferous than people with dry earwax. Anthropologists think this correlation reflects sweat production levels, with people with wet earwax sweating more profusely than people with dry earwax. Presumably, the mutation which alters the color and consistency of the earwax also impacts sweat production. Anthropologists think that reduced sweating may have offered an advantage to Asian peoples and Native Americans, and consequently, dry earwax became fixed within these populations.
What Is the Function of Earwax?
Earwax serves several functions. One is protecting the inner ear from water, dust particles, and microorganisms. Even though earwax is a solid substance, it allows air to flow through it to the inner ear. Yet, the high fat content of earwax makes it an ideal water repellent, keeping water away from the inner ear. The hair fibers in earwax serve a useful function, forming a meshwork that traps dust particles. And the acidic pH of earwax and the lysosomes from the cellular debris associated with it impart this waxy secretion with antibacterial and antifungal properties.
The fatty materials associated with earwax also help lubricate the skin of the inner ear canal as the earwax moves toward the outer ear. Earwax motion occurs via a conveyor action set up, in part, by the migration of epithelial cells toward the outer ear. These migrating cells, which move at about the same rate as fingernails grow, carry the earwax along with them. Jaw motion also helps with the earwax movement.
By comparing earwax from several animals and by video recording earwax in human ear canals, the GIT researchers discovered that earwax has special properties that make it a non-Newtonian fluid. It is solid at rest, but flows when under pressure. Apparently, the pressure exerted on the earwax from jaw movements helps it to flow toward the outer ear. This movement serves as a cleaning mechanism, carrying the debris picked up by the earwax toward the outer ear. Interestingly, the particles picked up by the earwax alter its consistency, from a waxy material, to a flaky solid that readily crumbles, making it easier to clear the outer ear, while making room for newer, cleaner earwax.
New Technology Inspired by Earwax
The GIT engineers recognized that, based on its physical properties, earwax could serve as an inspiration for the design of new types of filters that could protect electronics from water and dusty environments. With a bit of imagination, it is possible to conceive of ways to take advantage of shear-thinning behavior to design filters that could be readily replaced with cleaner ones, once they have trapped their limit of dust particles.
Biomimetics, Bioinspiration, and the Case for Intelligent Design
It has become rather commonplace for engineers to employ insights from biology to solve engineering problems and to inspire the invention of new technologies. This activity falls under the domain of two relatively new and exciting areas of engineering known as biomimetics and bioinspiration. As the names imply, biomimetics involves direct copying (or mimicry) of designs from biology, whereas bioinspiration relies on insights from biology to guide the engineering enterprise.
From my perspective, the use of biological designs to guide engineering efforts seems fundamentally at odds with evolutionary theory. Generally, evolutionary biologists view biological systems as the products of an unguided, historically contingent process that co-opts preexisting systems to cobble together new ones. Evolutionary mechanisms can optimize these systems, but they are still kludges, in essence.
Given the unguided nature of evolutionary mechanisms, does it make sense for engineers to rely on biological systems to solve problems and inspire new technologies? Is it in alignment with evolutionary beliefs to build an entire subdiscipline of engineering upon mimicking biological designs? I would argue that these engineering subdisciplines do not fit with the evolutionary paradigm. On the other hand, biomimetics and bioinspiration naturally flow out of a creation model approach to biology. Using designs in nature to inspire engineering only makes sense if these designs arose from an intelligent Mind.
“Engineers’ Muse: The Design of Biochemical Systems” by Fazale Rana (article)
“Beetles Inspire an Engineering Breakthrough” by Fazale Rana (article)