Scarce as Hen's Teeth

Most everyone knows that birds come with a hard beak, empty of any teeth. Thus the old saying I often heard my mom say, when something couldn't be found: “It's as scarce as hen's teeth.” Little did Mom know that hens—or, rather their deep ancestral forebears—once did have teeth. In fact, those toothy critters were birds' very deep ancestors (actually, dinosaurs), who lived over 100 million years ago.

In that ancient time the ancestors of today's birds were small, toothed dinosaurs that cohabited the planet with the really big toothy dinosaurs, like the formidable T-Rex. A great many species of dinosaurs presided over all living creatures on Earth, until that fateful day when an asteroid crashed down near the Mexican Gulf coast, 65 million years ago. The resultant disruption to Earth's climate soon wiped out the great dinos, but the smaller, feathered ones managed to squeak through.

Well before that asteroid crash, however, those bird ancestors had already lost their teeth. How do we know? New genetic analyses show that the toothed dinos long ago first lost their teeth at the front of their jaw, and the tooth loss then gradually moved rearward on the jaw. As this loss progressed, the hard beak slowly developed (I guess to give them something hard to mash their food with).

Bird evolution continued to occur, as the proto-birds also evolved flight feathers and even began to sing. As a fascinating example of how genes are shared across species (good evidence that we all co-evolved from even more primitive critters), the 50 or so genes that permitted birds to begin to sing are shared by us humans. These genes give us the ability to speak—and yes, sing, but certainly not like a bird.

But back to hen's teeth: Was a toothless bird more suited for surviving the asteroid impact than the dentally-equipped large dinosaurs? It was more likely a case of their larger size and the over-specialization of the huge dinos that did them in. In any case, the surviving proto-birds found countless available niches, after their dino cousins disappeared. When many niches are available, a species can rapidly multiply into many new species. That's why Earth currently supports more than 10,000 species of birds.

So, the proliferation of birds happened because the big dinosaurs, some 65 million years ago, became scarcer than hen's teeth.

Flying Dinosaurs?

In the past decade or so several feathered dinosaur fossils have been found in China. (What? Feathers on dinosaurs!? Didn’t they have scales or leathery skin, like crocodiles?) Feathers rarely last long enough to be fossilized like bones, so these findings have been exceptionally rare; yet several recent discoveries have confirmed that some dinos indeed sported feathers. Until those discoveries, it was thought by paleontologists that only prehistoric birds grew feathers. 

A related finding by scientists in recent years is that birds evolved from dinosaurs. So let's put these two results together: Birds fly and have feathers. Dinosaurs also had feathers but did not fly (among other things, they were too heavy). So what's going on here? What use may feathers have had for dinosaurs? Aren't they supposed to be for flying?

Those who misunderstand the process of evolution are inclined to think that feathers were “designed” for flight. But this is not how evolution works. There is no “intent,” no design to the evolutionary process. Rather, feathers appeared at some point in the deep past (for no “reason” at all), well before birds did—in their ancestral dinos. Hair-like follicles literally began erupting as rudimentary feathers, that slowly evolved into real feathers. When birds later came on the scene, they arrived with these inherited feathers, and then later further evolved the kinds of feathers that enabled them to fly. (Note that not all birds fly; some feathered extant species such as the ostrich can't flap themselves off the ground.) 

So, of what use were feathers to some of the dinosaurs that sprouted plumes; creatures that could not use them to fly? Well, feathers have some advantages over scales and hair, as skin covering. Besides, even today, most types of feathers are not used for flight. (Think of soft down.) Here are some useful functions that feathers can provide, that the flightless dinosaurs may have enjoyed:

1. Insulation—they are excellent for preserving body heat.
2. Colorful and decorative—sexual selection today has resulted in many birds becoming almost psychedelic in appearance, as males seek to attract mates. Dinos may have preceded birds in this swaggering sexual game.
3. Molting—feathers shed and then regrow, allowing a critter to change seasonal color and appearance, or to replace damaged ones.
4. Transformation—feathers can be fanned out and then retracted, to change size and appearance; useful for both sexual selection and to intimidate foes.
5. Maneuvering—feathered appendages can be extended to aid in balancing when running or gliding (the precursor to flying).
6. Defense—horny, stiff feathers can defend a critter, similar to how porcupines and hedgehogs do. (On my 6/17/13 posting, “Whistling Wings,” I wrote about how mourning doves use their wings in battle.)

As an example of a couple of these uses, I once watched my cat round the corner of the house with a bird in its mouth. Lying down to dine on his prize, he momentarily relaxed his jaw and the bird flew away, leaving the stunned cat with a mouthful of dry feathers, which the bird could later regrow.

Science does not yet know what uses dinos may have found for their feathers, or even how feathers further evolved, to be employed for various purposes. So dinosaurs may well have taken advantage of some of the offerings on the list above. We just don't know. Maybe someday more revealing fossils will be found.

New ways of preserving and analyzing fossils are rapidly being developed by paleontologists. DNA analysis is an especially powerful technique. Whether fossils from dinos or mammals or hominids—scientists are rapidly filling the gaps in our understanding of evolution. What fascinating stories they are telling!

(P.S. My 'puter is alive and active again! May it stay so for awhile.)

Dinosaur Luck

We humans tend to look with fascination upon the dinosaurs; being those formidable, scary beasts who once roamed ancient Earth’s surface (as well as modern film thrillers), but then suddenly became extinct, some 65 million years ago. They had their time, but just couldn’t last, we think. In fact, they had the bad luck of being susceptible to a meteorite that crashed into the Yucatan Peninsula.

In the aftermath of the impact, the dinosaurs disappeared, and little mammals—previously hovering on the fringes, cowering from the lizard monsters—prospered. Some of those mammals were our ancestors. Had the meteorite missed Earth, evolution would have played out a different story. If so, today’s most dominant species could be an intelligent Tyrannosaurus rex (with opposable thumbs, of course), rather than Homo sapiens. Bad luck, dinosaurs; good luck, quadrupedal and bipedal mammals.

But there’s more to the story than that. If we look even further back in time—some 200 million years and more—there were two great families of critters who competed to dominate the Earth: dinosaurs and crocodile ancestors. Both were big bruisers, both were prospering, both were diverse (fostering myriad species), both lived in similar places and filled similar ecological niches, and both were evolving at the same rate (fast). The future looked great for them. Something happened, however, that allowed the dinosaurs to shove aside the ancient crocs and go on to dominate the terrestrial ecosystem for over 100 million years, evolving into a fantastic variety of critters, while the crocs muddled along as smaller creatures, mostly hiding underwater.

What allowed the dinos to triumph, even when the croc ancestors initially had them outnumbered? Why didn’t the crocs have the dinos on the ropes? Until recently, scientists have assumed—given evolution’s survival-of-the-fittest depiction—that dinosaurs possessed some characteristic that helped them out-compete their crocodile competitors. It is not clear what that advantage may have been. The issue is under ongoing investigation.

One recently published scientific paper, however, suggests that the dinos did not possess any superior quality that the crocs lacked… it may have simply been pure luck. They dodged a bullet that the crocs caught. That’s fascinating!

Then a crashing meteorite some 65 million years ago brought the dinosaurs bad luck. They were kicked off the evolutionary mountain and we mammals replaced them. Prior to that—some 200 million years ago—another random incident may have smiled upon the dinos, displacing their competitors. A meteorite? A croc-specific disease? If so, it was the dinos’ good luck back then. Were it not for chance at that ancient time, we mammalian humans again might never have come about. Smart crocs (with opposable thumbs, of course) could have been the long time winners.

So, before we get too big a head about our dominance over today’s Earth, two facts should bring us humans a little humility: (1) we wouldn’t be here if it wasn’t for a string of favorable coincidences (our good luck) and (2) the extinct crocs and dinos flourished for a period a thousand times longer than we have been around. We can’t claim true bragging rights for at least another few million years.

Meek Heirs

The Beatitudes are one of the more enigmatic passages of the Bible. In fact, they sometimes seem downright oxymoronic. For example, the verse: “Blessed are the meek, for they shall inherit the earth.” It’s probably one of the more puzzling of the Beatitudes, and certainly goes against the popular thinking of today. “Nice guys finish last” is the trendier perception. Virtually nothing one sees in either the entertainment or political world suggests that anyone but the tough guys will triumph in the end.

Given that this Beatitude is such a riddle, it has spawned endless interpretations and explanations. I have no intention here of entering either the philosophical or theological arenas and getting mired down in speculation, or even try to guess what Jesus meant by this statement. Many of his biblical quotes pose paradoxes for us, and the true meaning of these statements probably has many layers and varying interpretations—depending on our particular circumstances. One of the beautiful attributes of Semitic languages—such as Aramaic and Arabic—is that they can have multiple meanings, depending on a given situation. Their relevance continues to speak to us, even as times change.

A similar paradoxical statement is found in the Tao Te Ching, the scripture of Taoism. Two example partial verses are:
“The hard and stiff will be broken. / The soft and supple will prevail.”
“The soft overcomes the hard, / The gentle overcomes the rigid.”

In contrast to popular interpretation, the dictionary definition of meek is to be quiet, gentle, and soft—not weak and frightened. Thus the Tao suggests—as does Jesus—that it is the gentle and soft people who will eventually triumph, that they will ultimately “inherit the earth.”

What started me thinking along this line recently was pondering the fact that mammals—once the meek critters skittering among the feet of the huge dinosaurs—eventually came to inherit their earth. For nearly 200 million years the dinosaurs ruled the planet. Think of that: 200,000,000 years! That’s a thousand times longer than we humans have been a separate species! During the dinosaurs’ realm the mammals were relegated to the shadows—meekly scurrying about the edges. The dinosaurs were big and powerful. Mammals were small (more diminutive than a kitty cat) and indeed quite weak.

In time, however (and aided by a crashing meteorite), mammals came to take control. Why did they (the “soft and supple”) prevail, while the dinosaurs (the “hard and stiff”) disappeared? How is it that the mighty dinosaurs, who were superbly fit at the time, did not survive this celestial catastrophe? The main reason is that the dinosaurs had evolved to a very static state of equilibrium, wherein they were no longer being tested and didn’t need to struggle to survive. They were boss! They could afford to become set in their ways, fat and happy, and not worry about any challenges that they could see on the horizon. Those puny little mammals were effectively sidelined and forced to scramble for the scraps. No competition.

Things worked fine (for 200 million years!) for the big guys, until the game suddenly changed. When times got tough in the wake of the meteorite crash (the planet went into a deep freeze and food nearly vanished), the entrenched, overconfident creatures couldn’t cope, while the humble and flexible (the meek) little mammals who were used to tough times, persevered. Mammals could roll with the climatic punches and better deal with adversity. They came to inherit the earth and Homo sapiens came to be the main heirs.

What might this meek inheritance issue mean to us today—other than maybe being an interesting puzzle? It seems quite possible to me that one of the key advantages the meek have is their patience—their ability to withstand and accept suffering. They have no choice, if they want to survive. The powerful hold the trump cards—no need for them to suffer. Those who are patient also tend to be gentle and humble—no sense in acting belligerent if you hold the short straw. Sooner or later, however, conditions always change. The current balance will be upset and the meek just might then be favored—especially if they have learned how to be flexible and nimble.

We are in a situation today wherein the meek are once again being ruled by the powerful—the masses of people who are being controlled by the very rich. Our culture tends to look upon the meek as weak and cowardly, and that is why they are easily manipulated by the powerful, and even thought to deserve their plight. But what if, instead, they are really gentle, soft, supple, and humbly patient? Might their time be coming, to inherit the earth? Even more interesting, that same reasoning might also apply to all of the human species—currently the dominant player on the planet. We humans tend to shove around many meek species—insects, birds, frogs, etc.—who may simply be waiting for their inheritance, while we are busy upsetting the environmental applecart and just possibly our earthly dominance with it.