Bug-Eared: Human and Insect Ears Share Similar Structures
By Marissa Fessenden | ScientificAmerican.com
In a noteworthy example of convergent evolution, Katydid ears have evolved components resembling those of humans, albeit on a much smaller scale
A rainforest katydid has ears that evolved to be remarkably like those of humans and other mammals. The insect’s hearing organ, although tucked in the crook of its front legs, has components that echo the structures of our own middle and inner ear, researchers have discovered.
In humans the outer portion of the ear gathers sound waves and funnels them toward the thin membrane of the eardrum, also called the tympanic membrane. The eardrum’s vibrations translate the pressure waves of sound to the three smallest bones in our body—the hammer, anvil and stirrup bones—which shake against a snail shell-shaped organ called the cochlea, whose curves are lined with sensory-cell hairs. The wiggling bones outside jiggle liquid inside the organ and trigger those cells, which send signals to the brain via the auditory nerve. Hair cells that respond to high frequencies are closest to the origin of wave propagation and cells that respond to low frequencies are located deeper within the cochlea.
Copiphora gorgonensis is a yellow-orange–faced katydid from Gorgona Island in Colombia. The insect’s hearing organ comprises a tympanic membrane that connects to a thin cuticle plate. Sound waves rock the tympanum and thus the cuticle plate like a seesaw. But the seesaw is lopsided, with the fulcrum closer to one end. This setup translates larger movements from air pressure waves to smaller, more powerful motions in the cuticle plate. The plate creates ripples in a fluid-filled chamber akin to an unfurled cochlea. Inside this chamber sensory cells are arranged like a keyboard from high- to low-frequency sensitivity.
The cuticle plate plays the same role as the tiny hammer, anvil and stirrup of mammalian ears, but in miniature. The katydid’s entire ear spans just 600 microns, a U.K.-based research team reports in the November 16 issue of Science. (A micron is one millionth of a meter.)
Read the full article at: scientificamerican.com
Latest News from our Front Page
Barbara Lerner Spectre On Twitter!
Kevin MacDonald writes in 2010:
In the video below, Barbara Lerner Spectre, who runs a government-funded Jewish study group in Sweden, makes the following remarkable statement—remarkable because she does not attribute anti-Jewish attitudes to irrational prejudices or even Muslims who hate Israel. Instead she says that it’s because of the “leading role” played by Jews in the movement toward multiculturalism:
“I think ...
Sweden investigating underwater wreckage as possible Russian submarine
What may be the wreckage of a Russian submarine is seen off the coast of Sweden
The Swedish military is studying a video taken by shipwreck hunters who say it shows a wrecked submarine, just off the country’s eastern coast, which appears to be Russian.
Ocean X Team, the company behind the discovery, said on its website: “It is unclear how old ...
The Dissidenti™™ and their frazzled hall monitors buzzsaw with talk about “cuckservatives.” It’s the shiv du jour, you see. As shivs go, it is in this ‘umble narrator’s opinion one of the more lethal of the semantic shanks employed by dark realists.
Lovers and haters of the Cuck Shiv gird for battle (well, the haters girdle for battle). The wielders love ...
The Inevitable - The Daily Beast Begins The Personal Attacks To Tear Down Trumpâ€¦.
Only the politically naive didn’t see this coming. The liberal outlet “The Daily Beast” begins to attack Donald Trump personally, through a method of hiding behind citations in old books and manipulating content/context delivery to attack their target.
The Daily Beast takes this very specific and very strategic approach because references to the statements/opinions of others allows them to avoid libel and ...
Residents of Dresden Wake up to Find Overnight, City Park Has Been Turned Into Migrant Camp For 2,000
The German city which dared to stand-up to their government’s policy of accepting Islamisation and mass migration appears to have been punished for dissent by the zero-notice imposition of a migrant camp.
Government employees stood by the entrance of a city park in Dresden, Saxony on Thursday night handing out fliers to passers-by informing them the next day the green space, ...
|More News » |