Story on Evolution of Birds Glosses Over Details
It takes more to turn a dinosaur into a bird than changing arm and leg ratios and reducing body size.
The summary of an article on Science Daily foretells what it will try to explain:
The key characteristics of birds which allow them to fly — their wings and their small size — arose much earlier than previously thought, according to new research that examined closely the Paraves, the first birds, and their closest dinosaurian relatives which lived 160 to 120 million years ago. Researchers investigated the rates of evolution of the two key characteristics that preceded flight: body size and forelimb length. In order to fly, hulking meat-eating dinosaurs had to shrink in size and grow much longer arms to support their feathered wings.
The article promised “New insights into origin of birds” by focusing on “key characteristics that preceded flight: Body size, forelimb length.” A little reflection makes it clear, though, that smaller size and shrinkage of forelimbs is not going to help a dinosaur caught falling out of a tree or running along the ground, assuming the two leading theories about the origin of flight (arboreal vs. cursorial). A small rock with long arms drops at the same rate as a large rock with short arms.
Mark Puttick and his team from the Universities of Sheffield and Bristol could say that these “key characteristics” are prerequisites only – not that they are explaining flight itself. Nevertheless, flight is a major theme in their statements. It’s what they aim to explain.
“We were really surprised to discover that the key size shifts happened at the same time, at the origin of Paraves,” said Mr Puttick of Bristol’s School of Earth Sciences. “This was at least 20 million years before the first bird, the famous Archaeopteryx, and it shows that flight in birds arose through several evolutionary steps.”
What did their research consist of? They “applied new numerical methods that calculate the rate of evolution of different characteristics across a whole evolutionary tree, and identify where bursts of fast evolution occurred.” Clearly this assumes evolution occurred. It is useless, therefore, to counter arguments for design, because they assume evolution to “prove” evolution. Even so, there are contradictions within the evolutionary scenario. For one, different traits helpful for flight “evolved” at different rates. For another, they have to account for certain dinosaurs surviving with long arms and stubby legs for 20 million years, without being able to use them for flight. It would seem those ungainly limb ratios would hinder survival on the ground with other fast-running theropods able to outrun and outcompete them. Evolutionary theory prohibits traits emerging with the goal of using them for flying millions of years later. Each variation has to have immediate survival value.
Without details, the article claims “a whole group of dozens of little dinosaurs were lightweight and had wings of one sort or another” that were “gliders or parachutists, spreading their feathered wings, but not flapping them.” How they could know that is curious, since they weren’t there as Jurassic birdwatchers. It would be necessary to know if these “dinosaurs” were secondarily flightless birds. More importantly, powered flight with flapping wings and all the accessory equipment is far different from gliding behavior, requiring new flight muscles (pectoralis and supracoracoideus) as well as related ligaments, nerves, and brain hardware and software to operate them.
Puttick’s paper in Evolution (co-authored with Gavin Thomas and Michael Benton) is entitled, “High Rates of Evolution Preceded the Origin of Birds.” The paper seems to focus on body size alone as the determining factor: “The high evolutionary rates arose primarily from a reduction in body size, as there were no increased rates of forelimb evolution.” The Aves class was unique, they claim, in its ratio of forelimb length to body size. “Traits associated with Aves evolved before their origin, at high rates,” they say – without accounting for how or why evolutionary rates should be high or low, nor why they should evolve before flying birds appeared. All their thinking depends, furthermore, on believing the evolutionary dates and the evolutionary trees.
The beautiful Illustra documentary Flight: The Genius of Birds gives a much more elegant and satisfying explanation for flight, because it doesn’t gloss over the details, but accounts for all the traits needed for powered flight: efficient one-way lungs, efficient digestive and excretory systems, the beautifully engineered flight muscles that provide a compact center of gravity, the hollow bones, the navigation systems, the sensory components (able not only to see details from the air but to sense the magnetic field), the exquisite design of feathers, and the behaviors that allow birds to take advantage of air currents, including the lift from other birds in formation flight (1/16/14). The integrated systems that allow an eagle to pick a fish out of a lake, a hummingbird (12/05/13) to hover in mid-air sucking its food out of a flower with a specialized nectar-trapping tongue, or a snowy egret with its large, elegant wings to fly between tree limbs without hitting them, are explained by appealing to what we know in our universal experience about complex functional systems. Intelligent design is a known “vera causa” (true cause) that can account for the observations.
Evolution, by contrast, comes up empty looking for a true cause for flight (7/30/13). Never do we see blind, unguided processes leading to complex functional systems with integrated parts contributing to the overall design goal. Intelligent design is, therefore, the best scientific explanation in contrast to the storytelling from the Darwin camp (9/30/13). The Tweety Rex fable looks downright silly by comparison. With its high perhapsimaybecouldness index, its stretchable rates of evolution (a clear ad hoc theory rescue device), and its copious use of magic words (emerged, arose, developed, appeared), it reduces to “birds evolved because they evolved.” If the public were allowed to hear the two explanations side by side, there would be no contest. Darwin’s flightless DODO birds would go running out of the auditorium in shame.