Ears Convert Energy

macro view of house cat's ear with fur in soft light with a gray background

Biological Strategy

Mammals

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Image: Alireza Khatami / Unsplash / Free non-commercial use

Transform Electrical Energy

Electric energy comes from electric potential energy, which is energy associated with a living system’s electric charge or its position relative to other electrically charged objects or living systems.

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Transform Mechanical Energy

Mechanical energy is made up of kinetic energy (the energy of an object in motion) and potential energy (stored energy). Organisms use mechanical energy in a variety of ways, including capturing prey, transporting seeds, and moving around.

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Transduce/Convert Signals

Sometimes a signal, such as sound or vibration, reaches a living system and needs to be converted into a different, usable form. This requires converting from one type of energy form to another. For example, organisms with eyes have photoreceptors at the back of the eyes that convert light into electrical pulses. These pulses travel to the brain and allows it to register color, shape, and detail.

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Mammals

Class Mammalia (“breast”): Bats, cats, whales, horses, humans

Mammals make up less than 1% of all animals on earth, but they include some of the most well-known species. We know first-hand some of the characteristics that make mammals unique, like having hair, being able to sweat, and producing milk through mammary glands. Another critical shared feature is a set of highly-specialized teeth. Unlike sharks or alligators, for example, whose teeth are generally all the same size and shape, mammals have differently shaped teeth in different areas of the jaws to target specific foods or foraging strategies.

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The hairs in mammalian ears convert motion into electrical energy and back in order to amplify sound via the prestin protein.

“A new Cambridge-based venture called IntAct Labs is investigating how to harness the power generating capabilities of life for space applications. It would involve the use of a called prestin found in human ear-hair as a means of powering space suits. The protein converts motion into electrical energy — and if it’s augmented with an electricity-conducting microbe, it could form self-healing, semi-living ‘skins’ that convert Martian wind and even the jogging and walking of astronauts into electricity. Prestin is found in the outer hair cells of the human ear. In the cell membranes of these cells, prestin also converts electrical voltage into motion, elongating and contracting the cell. This movement amplifies sound in the ear.” (Courtesy of the Guild)

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