Darwin Gets a Tongue Lashing

An article on the evolution of the tongue
deserves the Bronx cheer.

 

Tales of the tongue (Science Magazine, 25 May 2023). “Tales” is right. Our tongue lashing is not for author Elizabeth Pennisi, who is generally a fair reporter when it comes to Darwinism, and usually avoids the just-so storytelling method. The rebuke is for Darwin who made it acceptable to say that anything and everything “evolved” simply because it exists.

Since first evolving 350 million years ago, the tongue has taken myriad forms, unlocking new niches and boosting the diversity of life.

It just evolved. With its intricate muscles, nerves and sensors, the tongue should be seen as a marvel of engineering. But ever since the Darwin Party redefined science to exclude design and insist on naturalistic answers, biologists have gotten lazy. They no longer have to defend their Stuff Happens Law. It gets automatic peer review and acceptance, no matter how just-so the story.

On the plus side, this article will give readers an appreciation for the diversity and functionality of tongues in the animal kingdom.

“The incredible variation in vertebrate tongue form is replete with astonishing examples of almost unbelievable adaptation,” says Kurt Schwenk, an evolutionary biologist at the University of Connecticut. Salamanders whipping out sticky tongues longer than their bodies to snag insects; snakes “smelling” their environment with their forked tongue tips; hummingbirds slurping nectar from deep inside flowers; bats clicking their tongues to echolocate—all show how tongues have enabled vertebrates to exploit every terrestrial nook and cranny. In humans, still more functions crowded aboard the tongue. “I am amazed by everything we do with our tongue: eat, talk, kiss. It’s a central part of what it is to be a human,” says Jessica Mark Welch, a microbial ecologist at the Forsyth Institute.

Indeed, the hummingbird tongue was one of the marvels of engineering animated in a short film from Illustra Media. This animation was praised by one of the scientists who figured out how it works.

Amazing, isn’t it? But it evolved. It just evolved. No artist allowed. No engineer allowed. Stuff happens.

More Than an Isolated Organ

Pennisi points out that a tongue needs a brain to operate it. So how does evolution explain the tongue-brain system? Do they have a credible scientific explanation that is testable or falsifiable, or makes predictions?

Yet how tongues came about “is one of the biggest mysteries in our evolutionary history,” says Sam Van Wassenbergh, a functional morphologist at the University of Antwerp. Like other soft tissues, tongues are rarely preserved in fossils. Hidden inside the mouth, they defy easy observation. In the past decade, however, new technologies have begun to reveal tongues in action in different groups of animals. That work is beginning to yield new insights about the tongue’s evolutionary trajectories, and how its specializations fueled further diversification. Kory Evans, an evolutionary biologist at Rice University, says the more biologists learn, the more convinced they are that “tongues are really fantastic.”

The wording that the tongue’s “specializations fueled further diversification” seems illogical if “specializations” are accidents. Is Pennisi’s appeal to vaporware and futureware grounded in anything solid right now? No; she dodges to other things, like the fact that it’s hard to define what a tongue is.

A tongue turns out to be a slippery thing to define. Although tonguelike structures exist in virtually all vertebrates, from lampreys to mammals, “There is no clear definition to what makes a ‘true tongue,’” says Daniel Schwarz, an evolutionary biologist at the State Museum of Natural History Stuttgart. We tend to think of tongues as soft, muscular, and flexible—like our own.

These evolutionary biologists are sounding pretty useless. Maybe they should drop the adjective “evolutionary” and just try to act like old-fashioned biologists.

Similarities Again

The just-so story begins with a cartoon of fish evolving tongues as they climbed onto the land. To connect the dots, the evolutionary biologists compare bone structures between a coelacanth, Tiktaalik and a lizard. Tiktaalik had to crawl back into the water to swallow its Big Mac, but it was making progress. “Over time, the hyoid of early tetrapods got more complex, with perhaps the first inklings of a tongue.” They call it a prototongue. Or maybe it was the first inklings of a pre-prototongue. Was it really a tongue at all?

The next panel shows a lizard with a full-fledged tongue. How did that happen? Magic! It evolved—a completed transformation!

Once animals evolved tongues, they could become fully terrestrial and exploit new foods….

With the skeleton and musculature to support and operate a protrusible tongue, land verterbrates finally became adept at feeding on land.

Where did the skeletal changes come from? Where did the musculature to support and operate a tongue come from? They evolved, silly. No more questions. Maybe an eyeball of newt under the full moon prompted Tinkerbell to hit on the right incantation.

Based on experiments with newts, Schwarz thinks a prototongue became functional even before the transition to land. Like other salamanders, newts are aquatic when young but mostly terrestrial as adults. Their metamorphosis, and the change in feeding strategies that accompanies it, might be akin to water-to-land changes that occurred hundreds of millions of years ago. And it holds a clue to how those changes might have unfolded.

It “might have” happened. What’s the matter with you? Don’t you have an imagination? Don’t you respect evolutionary biologists? You wanted to see a prototongue: there it is—right inside the mouth of a baby newt (that has the full genes for a whole tongue—ahem—when it grows into an adult). Haeckel was right! We can watch the dramatic history of evolution in the embryo, just like the gill slits you had before you were born. (Not; they’re neither gills nor slits.)

Natural Selection the Omnipotent

Stuff happens, but once it happens, Natural Selection the Omnipotent fashions the “inkling” of a useful thing into rocket science. Watch Pennisi sneak the problem of tongue origins into the Darwin Party’s favorite euphemism for stuff happens, “emergence.”

The demands of feeding may have prompted the emergence of the tongue, but natural selection then tailored and honed it for myriad other purposes, sometimes creating “ridiculously crazy specialized systems,” Schwenk says. For example, web-toed salamanders (Hydromantes) whip out a sticky tongue to nab insects or other small arthropods, shooting their entire throat skeleton out through their mouth. This feeding mode involved retooling throat muscles, with one set storing elastic energy that could be instantaneously released to shoot out the tongue, and another set reeling the tongue back in.

Other salamanders, at least 7600 frogs and toads, as well as chameleons and other lizards have independently evolved other extreme forms of this quick-fire “ballistic” feeding. Chameleons, for example, launch their tongues at almost 5 meters per second, catching crickets in less than 1/10th of a second.

That little fleshy pad in Baby Newt’s mouth has come a long way. Talk about “convergent evolution,” this statement may set a record for Darwin Flubber: over 7,600 cases where amphibians “independently evolved” rocket tongues. Strange; the specialized ability for a salamander to nab an insect or a chameleon to catch a cricket in 1/10 second doesn’t strike us as ridiculous or crazy. It sounds rather cool.

Cool Tongues

The article then goes on to describe wonderful tongues in birds, including the nectar pump tongue in hummingbirds shown in the video above. Incidentally, the researcher who figured it out is mentioned with some new information, including a beautiful photo of the nectar flaps in liquid.

After that, Pennisi gives instances of highly functional tongues in mammals. Without the e-word evolved, this article could serve as a splendid showcase of intelligent design in the animal kingdom.

It’s in mammals, however, that the tongue displays its fullest versatility. The mammalian tongue has evolved into an intricate network of muscle fibers capable of moving in complex ways even without any bones, tendons, or joints. It contributes to suckling in most species, helps with thermoregulation in some (picture a panting dog), and takes on even more specialized tasks in a few, such as producing the sounds used for echolocation in bats and speech in humans. And it hosts the taste buds that help guide feeding in all these species. “The tongues of most mammals perform great feats,” Hu says. “It’s truly a multifunctional tool, and has only received less attention because it is less accessible than an animal’s external appendages.”

In humans and other mammals, the tongue has another key job to do: positioning the food for swallowing. On that subject, a Darwin-free press release from the Max Delbruck Center on May 25 explained “the mechanisms behind swallowing,” a very intricate process involving the tongue, the brain stem, the vagus nerve, and sensors in the esophagus.

“So, the esophagus isn’t just a tube that connects the mouth to the stomach,” he says. “It uses mechanosensory feedback to fulfill its function.” Birchmeier adds that without these cells in the vagus nerve, food gets stuck in our esophagus. In some of the mice, it actually flowed back into the throat.

The article describes swallowing disorders that can occur when one part is defective. An animal that cannot swallow is not likely to pass on its genes to the next generation. Did all those parts show up together for it to work?

Pennisi says even more about this in an excellent summary of the tongue’s role in swallowing:

The tongue’s most essential job in mammals is to position food to be chewed and swallowed. Depending on the species, that could mean shifting the food from one side to another with each bite or confining it to just one side, while the tongue itself stays safely away from chomping teeth. Then, with the addition of saliva it helps produce, the tongue shapes mashed food into a rounded “bolus” that can fit easily down the throat. Finally, it pushes that bolus back to be swallowed, making sure no food enters the airways. In a sense, the tongue has become a “hand of the mouth,” says J.D. Laurence-Chasen, a biologist at the National Renewable Energy Laboratory.

Pennisi’s Grand Darwin Finale

Darwinese only returns at the end of Pennisi’s paean to the tongue. Here, Charles Darwin makes a cameo appearance, and tongue evolution takes a bow as the source of our humanity. She entertains the notion that brain enhancement that accompanied the tongue gave rise (emergence) to the hand. That changed everything. It gave rise to thought itself!

Whishaw thinks a similar brain region exists in humans and could help explain why so many people gesture as they talk, why children learning to write often twist their tongues as their fingers shape letters—a phenomenon noted by Charles Darwin—and even why Mahomes sticks his tongue out before a pass. He suspects many people move their tongue as they are about to use their hands—but because their mouth stays closed, no one is the wiser.

A common brain region for the hand and tongue makes evolutionary sense, Whishaw says. In early land animals, a dexterous tongue was essential for feeding; later, when some animals began grabbing food with their limbs, evolution might have coopted the same brain circuitry guiding the tongue to coordinate hand movements. He speculates that even more complex behaviors—such as thinking—could have arisen from the brainpower that initially evolved to coordinate the tongue. “I think it is the center of our being, as crazy as that might seem.”

Yes, it does seem crazy. The tongue emerged, which led to the emergence of thinking, which led to the emergence of thinking that the tongue emerged? Something looks amiss here.

It makes “evolutionary sense” to one with the sophoxymoronia mind virus, a frequent malady infecting the brains of evolutionary biologists. This virus is often accompanied by the Yoda Complex, but it is unclear if one is the cause of the other. One thing is clear: anyone claiming that the Stuff Happens Law can explain the tongue or any other complex organ deserves a tongue lashing.

It pains us to award Stupid Evolution Quote of the Week to Elizabeth Pennisi, a talented science writer. The facts she gives about animal tongues are really interesting and good, but we wish she could be more critical of Darwinian just-so stories. If she were, it would probably end her career. The Darwin Party is ever on the prowl, sniffing for hints of insufficient allegiance to King Charley. Many scientists and reporters have paid dearly for thinking critically about evolution.

Pennisi and the evolutionary biologists she quotes seem to have cases of human design clouding their definitions of the Stuff Happens Law. We all know that human inventions are quickly copied and diversified, whether cars, cell phones, or spacecraft. Darwinians seem to think that “nature” acts similarly. Some clever part “emerges” and then gets diversified mindlessly by Darwin’s blind watchmaker, tinkering in his lab. Back in the day, neo-Darwinism was limited to chance mutations and natural selection. Everything happened by chance, without guidance or purpose. But now, a personified Natural Selection the Omnipotent “tailors” and “hones” proto-tongues into thousands of varieties of tongues: rocket tongues, tongues with a sense of smell, tongues that can sip nectar with a fluid trap, tongues that can echolocate, and tongues that can tell fibs.

Speaking of fibs, the Word of God warns about the evil uses of the tongue. The Darwin Dictionary has definitions of confability (the ability to confabulate fables) and confibility (the ability to confabulate fibs). The letter of James refers to the tongue as a metonymy for evil speech emanating from an evil mind. In this picturesque and trenchant passage, he warns Christ followers to learn to control this powerful organ in the mouth.

For we all stumble in many ways. And if anyone does not stumble in what he says, he is a perfect man, able also to bridle his whole body. If we put bits into the mouths of horses so that they obey us, we guide their whole bodies as well. Look at the ships also: though they are so large and are driven by strong winds, they are guided by a very small rudder wherever the will of the pilot directs. So also the tongue is a small member, yet it boasts of great things.

How great a forest is set ablaze by such a small fire! And the tongue is a fire, a world of unrighteousness. The tongue is set among our members, staining the whole body, setting on fire the entire course of life, and set on fire by hell. For every kind of beast and bird, of reptile and sea creature, can be tamed and has been tamed by mankind, but no human being can tame the tongue. It is a restless evil, full of deadly poison. With it we bless our Lord and Father, and with it we curse people who are made in the likeness of God. From the same mouth come blessing and cursing. My brothers, these things ought not to be so.

Solomon wrote 19 proverbs about the power of the tongue: the healing tongue of the wise, and the perverse tongue of the liar or fool. “Death and life are in the power of the tongue,” he said, “and those who love it will eat its fruits” (Proverbs 18:21).

Exercise: Practice some awareness of your tongue for the next hour. What are some of the things your tongue does for you? I know as a brass player that tonguing is an essential part of performing a wind instrument. We do “double-tonguing” and “triple tonguing” to hit the fast notes, which can be remarkably rapid. That takes muscles that pronounce tu-ku or tu-tu-ku in succession quickly. It takes training to get it right (try it now). How do you use your tongue when not talking or eating? Write down some observations.