New Theory Of The Evolution Of Bird Flight Linked To Parental Care

Modern birds evolved from ground-dwelling reptiles as their increasingly refined parenting skills led them into the trees, where they could better protect their young, proposes a researcher at the University of California, Davis.

This new theory, contradicting the two leading theories on the evolution of avian flight, appears this month in the German journal "Archaeopteryx," named after a feathered fossil with both reptilian and birdlike traits.

"The evidence indicates that a whole suite of behavioral and physical traits, including feathers and wings, evolved along with improved parenting and brood-care traits," said James Carey, a UC Davis demographer and ecologist. "Once the precursors to birds began to fly, the ecological interplay of flight and parental care may have been mutually reinforced, continuing the evolution of both traits and accelerating the rate at which the physical features of the modern bird were acquired."

The origin of bird flight is a fundamental issue in avian biology and in overall evolutionary theory. Many scientists point to the fossilized specimens of Archaeopteryx as evidence that there was a transitional vertebrate species that developed during the evolution from reptilian dinosaurs to birds. Furthermore, they suggest that the development of flight may explain why birdlike dinosaurs avoided extinction.

Until now, there have been two basic theories on the origins of bird flight. The first, the arboreal theory, is a tree-to-ground model, suggesting that birds' primitive ancestors were tree-dwellers that leapt from branch to branch. Through the ages, the ability to first glide and later fly developed because gliding slowed their fall to earth when they missed a branch.

The second, the cursorial theory, is a ground-up model that suggests that birds evolved from four-legged reptiles. According to this theory, scales on these creatures' front limbs gradually developed into feathers that gave them upward thrust when they ran and eventually enabled them to fly.

Carey maintains that both of these theories have major flaws. If the arboreal theory were accurate, birds' early ancestors would more likely have been four-legged creatures that developed membranes between their front and back legs, much like flying squirrels or bats, he asserts.

And, if the cursorial theory were true, there should have been obvious useful advantages to each form that developed between the four-legged reptile and the bird, he maintains. He is not persuaded by the suggestion that the intermediate stages of this line used their feathers, first developed to conserve heat, to swat insects from the air.

On the other hand, the parental-care theory is consistent with both the physical and behavioral changes that appear to have occurred as reptiles evolved into winged dinosaurs and finally into modern birds, Carey says.

He suggests that modern birds' very early ancestors were reptiles that established and guarded their nests on the ground, much like crocodiles. Over time, these creatures developed hard-shelled rather than leathery eggs and the ability to modulate their own body temperature in order to provide a more constant environment for their developing young. Scales evolved into feathers, better camouflaging and insulating the parents.

In time, these early ancestors of birds developed more advanced techniques for caring for their young. They started to feed their young in the nest, pumping liquid food or placing small food items in their mouths. They also began to produce fewer and more dependent offspring and smaller eggs, and began nesting in bushes and then small trees to better protect their offspring from predators.

Gradually the forelimbs of these creatures became feathered and even more elongated, enabling them to better manipulate their eggs and to "parachute" from their tree nests to a soft landing. Later they would develop the ability to glide and eventually fly by flapping their wings.

Carey hypothesizes that bird beaks also evolved in the context of parental care. The beak, he suggests, serves both as a point source of food for small hatchlings in the same way the nipple is used to feed mammalian young and also as a tool for sophisticated nest construction. This concept diverges from the commonly held notion that birds evolved beaks because they weigh less than teeth and so are better adapted for flight.

He points out that flight provided these prehistoric ancestors of birds with numerous advantages including the ability to safely place their young high in trees and cliffs, maximize their food sources through seasonal migration, and supply more and higher quality food by expanding their foraging range.

He adds that the fossil record, specifically Archaeopteryx, provides ample evidence that the evolution of parental care was the main driving force behind the evolution of avian flight. For example:

* Fossil specimens of Archaeopteryx have forelimb claws, supporting the concept that ancient bird ancestors were tree-dwellers;

* The feathers on Archaeopteryx fossils appear to be much more advanced than the creature's other birdlike traits, which is consistent with the notion that feathers evolved very early to shield the nest-sitting adults from the elements;

* The beak of Archaeopteryx is quite primitive, which is in keeping with the concept that sophisticated nest-building and feeding behaviors emerged much later in the development of parenting traits; and

* While Archaeopteryx had highly advanced feathers, its bone and muscle structure appear to have equipped it for only limited flight. This makes sense, according to the parental care theory, which asserts that flight developed long after the reptiles with their protective feathers moved into the trees.

Additionally, recent findings in Asia of feathered dinosaurs provide further evidence that feathers evolved before flight, Carey adds.

In this paper, he also discusses why flying dinosaurs with nonfeathered membrane-like wings, such as the pterosaurs, became extinct. He suggests that they perished, not because they were out-competed by birds but because they lacked the sophisticated parenting skills needed to cope with a changing environment.

Carey developed the parental-care theory of avian flight evolution while doing research supported by the National Institute on Aging, the Duke University Center for Demographic Studies and the UC Berkeley Center for the Economics and Demography of Aging.

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Note: This story has been adapted from a news release issued by University Of California - Davis for journalists and other members of the public. If you wish to quote from any part of this story, please credit University Of California - Davis as the original source. You may also wish to include the following link in any citation:

The really big lie which is being promulgated by the evos is that the dialectic is between evolution and religion. That's BS. In order to have a meaningful dialectic between evolution and religion, you would need a religion which operated on an intellectual level similar to that of evolution, so that the debate would be between the evolutionists, and the voodoo doctors: Dick Dawkins vs Jr. Doc Duvalier.

But the real dialectic is between evolution and mathematics. Professing belief in evolution at this juncture amounts to the same thing as claiming not to believe in modern mathematics, probability theory, and logic. It's basically ignorant.

Evolution has been so thoroughly discredited at this point that you assume nobody is defending it because they believe in it anymore, and that they are defending it because they do not like the prospects of having to defend or explain some expect of their lifestyles to God, St. Peter, Muhammed...

To these people I say, you've still got a problem. The problem is that evolution, as a doctrine, is so overwhelmingly STUPID that, faced with a choice of wearing a sweatshirt with a scarlet letter A for Adulteror, F for Fornicator or some such traditional design, or or a big scarlet letter I for IDIOT, you'd actually be better off sticking with one of the traditional choices because, as Clint Eastwood noted in The Good, The Bad, and The Ugly:

God hates IDIOTS, too!

The best illustration of how stupid evolutionism really is involves trying to become some totally new animal with new organs, a new basic plan for existence, and new requirements for integration between both old and new organs.

Take flying birds for example; suppose you aren't one, and you want to become one. You'll need a baker's dozen highly specialized systems, including wings, flight feathers, a specialized light bone structure, specialized flow-through design heart and lungs, specialized tail, specialized general balance parameters etc.

For starters, every one of these things would be antifunctional until the day on which the whole thing came together, so that the chances of evolving any of these things by any process resembling evolution (mutations plus selection) would amount to an infinitessimal, i.e. one divided by some gigantic number.

In probability theory, to compute the probability of two things happening at once, you multiply the probabilities together. That says that the likelihood of all these things ever happening, best case, is ten or twelve such infinitessimals multiplied together, i.e. a tenth or twelth-order infinitessimal. The whole history of the universe isn't long enough for that to happen once.

All of that was the best case. In real life, it's even worse than that. In real life, natural selection could not plausibly select for hoped-for functionality, which is what would be required in order to evolve flight feathers on something which could not fly apriori. In real life, all you'd ever get would some sort of a random walk around some starting point, rather than the unidircetional march towards a future requirement which evolution requires.

And the real killer, i.e. the thing which simply kills evolutionism dead, is the following consideration: In real life, assuming you were to somehow miraculously evolve the first feature you'd need to become a flying bird, then by the time another 10,000 generations rolled around and you evolved the second such reature, the first, having been disfunctional/antifunctional all the while, would have DE-EVOLVED and either disappeared altogether or become vestigial.

Now, it would be miraculous if, given all the above, some new kind of complex creature with new organs and a new basic plan for life had ever evolved ONCE.

Evolutionism, however (the Theory of Evolution) requires that this has happened countless billions of times, i.e. an essentially infinite number of absolutely zero probability events.

And, if you were starting to think that nothing could possibly be any stupider than believing in evolution despite all of the above (i.e. that the basic stupidity of evolutionism starting from 1980 or thereabouts could not possibly be improved upon), think again. Because there is zero evidence in the fossil record (despite the BS claims of talk.origins "crew" and others of their ilk) to support any sort of a theory involving macroevolution, and because the original conceptions of evolution are flatly refuted by developments in population genetics since the 1950's, the latest incarnation of this theory, Steve Gould and Niles Eldredge's "Punctuated Equilibrium or punc-eek" attempts to claim that these wholesale violations of probabilistic laws all occurred so suddenly as to never leave evidence in the fossil record, and that they all occurred amongst tiny groups of animals living in "peripheral" areas. That says that some velocirapter who wanted to be a bird got together with fifty of his friends and said:

Guys, we need flight feathers, and wings, and specialized bones, hearts, lungs, and tails, and we need em NOW; not two years from now. Everybody ready, all together now: OOOOOMMMMMMMMMMMMMmmmmmmmmmmmmmmmmmmmmmmmmmmmmm.....

You could devise a new religion by taking the single stupidest doctrine from each of the existing religions, and it would not be as stupid as THAT.

But it gets even stupider.

Again, the original Darwinian vision of gradualistic evolution is flatly refuted by the fossil record (Darwinian evolution demanded that the vast bulk of ALL fossils be intermediates) and by the findings of population genetics, particularly the Haldane dilemma and the impossible time requirements for spreading genetic changes through any sizeable herd of animals.

Consider what Gould and other punk-eekers are saying. Punc-eek amounts to a claim that all meaningful evolutionary change takes place in peripheral areas, amongst tiny groups of animals which develop some genetic advantage, and then move out and overwhelm, outcompete, and replace the larger herds. They are claiming that this eliminates the need to spread genetic change through any sizeable herd of animals and, at the same time, is why we never find intermediate fossils (since there are never enough of these CHANGELINGS to leave fossil evidence).

Obvious problems with punctuated equilibria include, minimally:

1. It is a pure pseudoscience seeking to explain and actually be proved by a lack of evidence rather than by evidence (all the missing intermediate fossils). Similarly, Cotton Mather claimed that the fact that nobody had ever seen or heard a witch was proof they were there (if you could see or hear them, they wouldn't be witches...) The best example of that sort of logic in fact that there ever was was Michael O'Donahue's parody of the Connecticut Yankee (New York Yankee in King Arthur's Court) which showed Reggie looking for a low outside fastball and then getting beaned cold by a high inside one, the people feeling Reggie's wrist for pulse, and Reggie back in Camelot, where they had him bound hand and foot. Some guy was shouting "Damned if e ain't black from ead to foot, if that ain't witchcraft I never saw it!!!", everybody was yelling "Witchcraft Trial!, Witchcraft Trial!!", and they were building a scaffold. Reggie looks at King Arthur and says "Hey man, isn't that just a tad premature, I mean we haven't even had the TRIAL yet!", and Arthur replies "You don't seem to understand, son, the hanging IS the trial; if you survive that, that means you're a witch and we gotta burn ya!!!" Again, that's precisely the sort of logic which goes into Gould's variant of evolutionism, Punk-eek.
2. PE amounts to a claim that inbreeding is the most major source of genetic advancement in the world. Apparently Steve Gould never saw Deliverance...
3. PE requires these tiny peripheral groups to conquer vastly larger groups of animals millions if not billions of times, which is like requiring Custer to win at the little Big Horn every day, for millions of years.
4. PE requires an eternal victory of animals specifically adapted to localized and parochial conditions over animals which are globally adapted, which never happens in real life.
5. For any number of reasons, you need a minimal population of any animal to be viable. This is before the tiny group even gets started in overwhelming the vast herds. A number of American species such as the heath hen became non-viable when their numbers were reduced to a few thousand; at that point, any stroke of bad luck at all, a hard winter, a skewed sex ratio in one generation, a disease of some sort, and it's all over. The heath hen was fine as long as it was spread out over the East coast of the U.S. The point at which it got penned into one of these "peripheral" areas which Gould and Eldredge see as the salvation for evolutionism, it was all over.

The sort of things noted in items 3 and 5 are generally referred to as the "gambler's problem", in this case, the problem facing the tiny group of "peripheral" animals being similar to that facing a gambler trying to beat the house in blackjack or roulette; the house could lose many hands of cards or rolls of the dice without flinching, and the globally-adapted species spread out over a continent could withstand just about anything short of a continental-scale catastrophe without going extinct, while two or three bad rolls of the dice will bankrupt the gambler, and any combination of two or three strokes of bad luck will wipe out the "peripheral" species. Gould's basic method of handling this problem is to ignore it.

And there's one other thing which should be obvious to anybody attempting to read through Gould and Eldridge's BS:

The don't even bother to try to provide a mechanism or technical explaination of any sort for this "punk-eek"

They are claiming that at certain times, amongst tiny groups of animals living in peripheral areas, a "speciation event(TM)" happens, and THEN the rest of it takes place. In other words, they are saying:

ASSUMING that Abracadabra-Shazaam(TM) happens, then the rest of the business proceeds as we have described in our scholarly discourse above!

Again, Gould and Eldridge require that the Abracadabra-Shazaam(TM) happen not just once, but countless billions of times, i.e. at least once for every kind of complex creature which has ever walked the Earth. They do not specify whether this amounts to the same Abracadabra-Shazaam each time, or a different kind of Abracadabra-Shazaam for each creature.

I ask you: How could anything be stupider or worse than that? What could possibly be worse than professing to believe in such a thing?

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