Birds Evolved Fast Except When They Evolved Slow
To make a dinosaur fly, you have to adjust the rate of evolution by orders of magnitude, and commit other scientific fallacies.
Birds evolved very fast after a long, slow period, Daniel Ksepka argues in Current Biology:
With approximately 10,000 living species, ranging from tiny nectivorous hummingbirds to soaring raptors to secondarily aquatic penguins, birds represent one of the most remarkable vertebrate radiations. How did birds achieve such astonishing diversity? Birds split from their closest living relatives, the crocodilians, approximately 250 million years ago. This deep split places questions about the earliest phases of avian evolution beyond the reach of methods sampling only extant taxa. Thus, evolutionary biologists must turn to the fossil record. An ever-growing trove of fossil theropods — the clade of feathered bipedal dinosaurs that includes such well-known taxa as Velociraptor and Tyrannosaurus — provides the raw data needed to reconstruct the crucial steps preceding the appearance of primitive birds roughly 150 million years ago. In a recent issue of Current Biology, Stephen Brusatte and colleagues harness the fossil record of theropods to provide insight into rates of evolution near the transition between non-avian dinosaurs and birds.
Using an expansive morphological character dataset and methods for estimating rates of evolution, Brusatte and colleagues identify a faster rate of skeletal character change along the theropod lineage leading to birds, as well as a faster rate within birds (as a clade) compared to other theropod clades. Conversely, the study detects no great leap between advanced theropods and basal birds in morphospace (a multidimensional representation of the possible form of an organism, with each axis representing variation of a specific feature). This drives home the message that, although birds represent the endpoint of an exceptional fast-evolving lineage in the theropod evolutionary tree, there is no wholesale morphological transformation on the particular branch leading directly to birds (Figure 1). Rather, the earliest birds were extremely similar to their non-avian theropod contemporaries, and it was after the basic bird ‘body plan’ was acquired that they began a runaway diversification.
One of the highlights of Brusatte’s paper is the claim, “The assembly of the avian body plan unlocked great evolutionary potential” (see sophoxymoronia in the Darwin Dictionary). Apparently, he thinks, evolutionary potential is all that is needed for wondrous things to happen, like “assembling” a land-dwelling theropod with puny arms into something new that could grow wings and take to the skies in a relatively short period of time. As positivistic as the story is told, it requires different rates of evolution for different lineages. Evolution is fast except when it is slow.
Brusatte admits that “The evolution of birds from theropod dinosaurs was one of the great evolutionary transitions in the history of life.” Yet despite all the interest in this transition, “The macroevolutionary tempo and mode of this transition is poorly studied.” That’s surprising, he continues, because “it may offer key insight into major questions in evolutionary biology, particularly whether the origins of evolutionary novelties or new ecological opportunities are associated with unusually elevated ‘bursts’ of evolution.” Where have the Darwinists been for 154 years?
For support of his quest, Brusatte went on a tree-building exercise, placing all the new Chinese “feathered dinosaurs” and other theropods into an ancestral diagram. His resulting tree shows nothing major happening until the bird form appears, then whoosh! Evolution took off in a way George Gaylord Simpson suggested more than 60 years ago: “high rates of morphological evolution after the development of a novel body plan may be a common feature of macroevolution.”
If evolution is supposed to be a gradual process, though, this sounds like a case of special pleading. Evolution was fast during the Cambrian explosion, but nearly dead still for all the living fossils in the world today. A novel body plan, furthermore, is not something amenable to an unguided process. Since mutation and selection have no foresight, the “assembly” of dozens of new cell types into tissues, organs, and systems is beyond the reach of evolution, as Steven Meyer argues in Darwin’s Doubt about the Cambrian animals. New body plans show positive evidence of intelligent design (see also the Illustra film Darwin’s Dilemma).
Illustra Media’s recent documentary Flight: The Genius of Birds argues that the constraints for powered flight must be carefully coordinated. It’s not enough to have wings if the muscles are not there to power them. It’s not enough to have hollow bones if the digestive system has not been assembled yet. In birds, the center of gravity has been relocated, the weight of every component reduced, and new sensory systems introduced, such as magnetosensing and star navigation, along with the “flight software” (brain instincts) to use them. Sticking feathers on a ground-running dinosaur won’t make it fly.
Brusatte’s tree can only be made to look like an evolutionary sequence by assuming evolution for the dates. Fossils do not come with dates on them. They cannot be dated by radiometric means, even if that were reliable. By assuming which strata go in which order (because of the fossils they contain), paleontologists assign some fossils to be “primitive” and others to be “derived.” Without those assumptions of time and of evolution, a very different picture could be drawn. Paleontologists agree that many of the specimens overlap or were contemporaries.
“Primitive” birds like Archaeopteryx have been repeatedly moved into the tree, off the tree, and back again. Brusatte’s tree puts it back again as a basal bird, but that creates another evolutionary improbability: “Strikingly, if Archaeopteryx could fly — a subject of debate in its own right — this phylogeny would require two separate origins of powered flight.” That would be a hard pill to swallow for an unguided process. How much more so when it arose four times? (insects, pterosaurs, birds, bats). There’s a term for this phenomenon: “convergent evolution.” An outsider would consider this another ad hoc case of special pleading, bandaging up an injured theory with a mere label.
Another trick of the evolutionary trade is possibility thinking. Ksepka says, for instance, “Although these results differ on precisely when body size evolution speeds up, broad consensus is emerging that small size is the result of a long-term trend culminating in breaking through the size limit that enabled powered flight.” But will “enabling powered flight” make it happen? A landing strip enables flight, but a car driving down it will not enable it to take off, except, perhaps, in Back to the Future II. Furthermore, some of the extinct flying pterosaurs and today’s giant condors are larger and heavier than some extinct theropods, so why should it be necessary to “break through the size limit” by “miniaturization” to enable flight? Who conducted the miniaturization process? Nobody, in evolutionary thinking; it was the result of an unplanned, unguided natural process. No theropod could see flight coming in millions of years in order to prepare for it.
The confident-sounding papers, therefore, rely on ad hoc reasoning to speak of a “burst of evolution” in order to fit the fossil record to the Darwinian ancestry belief. Ksepka writes, “the hypothesis that the completion of the avian skeletal plan and development of powered flight opened the door to new ecological niches and triggered a burst of evolution.” Who was the foreman for this plan? Who oversaw the “development” of powered flight, with all the independent systems coming together perfectly in a bird? This is belief masquerading as evidence. A tree constructed with the evolutionary conclusion embedded up front can hardly be convincing to an unbeliever. If the rate of evolution was steady, that might at least look like a law of nature. Isn’t science supposed to build its hypotheses on laws of nature?
“Once believed to be a diagnostic feature of birds, feathers are now known to have evolved in dinosaurs well before the first birds,” three evolutionists write in Science Magazine. In “Beyond the Rainbow,” they speculate:
Protofeathers probably evolved in early dinosaurs for insulation and preceded planar feathers in coelurosaurians. Planar feathers, in turn, preceded flight or gliding. Miniaturization along the bird stem line led to a trade-off between color display and insulation, which could have been solved by the evolution of planar feathers serving both functions.
Once again, a critic could note that an abundance of feathers on a dinosaur will never make it fly. Whatever these integumentary structures were on non-avian dinosaurs, unless they were accompanied by all the flight systems of birds, they would have been completely earthbound. The constraints for powered flight are very stringent. One doesn’t just partly fly. As Paul Nelson comments in the Illustra film, “Flight requires not just having a set of wings, but having your entire anatomy coordinated for that function.” The only vera causa (true cause) capable of achieving an end goal and arranging all the systems for a severely-constrained function like powered flight is intelligence. Creationist Jonathan Sarfati has quipped that a Boeing 747 is composed of five million non-flying parts.
Since the three evolutionists merely assume that the presence of feathers or “protofeathers” on a dinosaur will eventually lead to flight, one wonders who is really “Beyond the Rainbow.” The write-up on PhysOrg mentions that the precursor “ancient lizards had a highly developed ability to discern color” without explaining how that complex ability emerged in the first place. Did color vision drive the evolution of feathers, or was it the other way around? Insert your just-so story here.
Seeing the Same Data a New Light
There’s another way to look at birds and dinosaurs. That’s to approach the data with design thinking. The PhysOrg article just mentioned includes some beautiful photos of intricately patterned and colorful feathers, but they’re not only beautiful, they are functional. An article on Science Daily reports that engineers at RMIT have been inspired by feathers to create anti-turbulence technology. They realize that feathers are exquisitely designed for efficient flight and smooth landings. The “feathers” on the Virgin Galactic craft that crashed in the desert (BBC News) were not really feather-like, but we can observe that birds rarely crash-land, thanks in large part to their feathers. Why not learn from the birds? “Inspired by nature’s own anti-turbulence devices – feathers – researchers have developed an innovative system that could spell the end of turbulence on flights.” This kind of outlook at least has some good practical use.
Biomimetics is a form of design thinking that frequently looks to birds for inspiration. Here’s a new case reported on Science Daily: “Running robots of future may learn from world’s best two-legged runners: Birds.” An ostrich can outrun a horse, but for its size, a quail achieves similar performance with the same efficient strategy.
Running birds come in an enormous range of sizes, from tiny quails to an ostrich that has 500 times as much body mass. Most, but not all, can fly, but spend most of their lives on the ground, and they don’t always look the most graceful when they run. But researchers found that they maximize the results while keeping their priorities straight — save energy and don’t break a leg.
Those are good priorities for robot design, too. It may surprise many that birds are superior to any other two-legged runner that we know of in the animal kingdom. (Whether that was true for theropod dinosaurs can only be inferred, but even if so, it would only reinforce the biomimetics approach with more examples.) The tacked-on evolutionary story carries no evidential weight here: “Their skills may have evolved from the time of the dinosaurs and they may now be superior to any other bipedal runners — including humans,” the article says. A design thinker doesn’t need to know where something evolved from. He or she only needs to know that it works, and can be reverse engineered for practical applications.
Vote for the best approach to the data: (1) evolution, which is controversial, debatable, ad hoc, constantly revised, unobservable, unrepeatable, dependent on weird phrases like “evolutionary potential” and, at the bottom line, effectively useless; or (2) intelligent design, which provides a vera causa adequate for the observations, fits the data, employs well-known goal-directed processes we are familiar with, and leads to useful applications. It’s election day. Vote early; vote often.