Evolution for the Birds
Birds have not evolved as much as evolutionary theories about them have.
Among the vast diversity of birds alive today, from ostriches to hummingbirds, only a few have been given detailed analysis by evolutionists. Those are Darwin’s finches. Is this indeed the case? Look what Cooney et al. say in Nature this week:
Small clades such as Darwin’s finches demonstrate that natural selection is the driving force of adaptive radiations, but how microevolutionary processes scale up to shape the expansion of phenotypic diversity over much longer evolutionary timescales is unclear.
While Darwin’s finches are the best-studied example (2/12/15), the only other “small clades” they refer to are Hawaiian honeycreepers and Malagasy vangas. Even if they had more examples, though, their statement is problematic at several points. For one, natural selection is not a “driving force” (see 10/03/15). For another, “adaptive radiation” presupposes Darwinian evolution rather than demonstrating it (i.e., evolutionists typically find the tips of branches of phylogenetic trees, but not the nodes or branching points of ancestral lines). Third, the authors assume that microevolution can scale up to macroevolution, but they freely admit it is “unclear” how. That’s why they went to work to address the problem.
Here we address this problem on a global scale by analysing a crowdsourced dataset of three-dimensional scanned bill morphology from more than 2,000 species. We find that bill diversity expanded early in extant avian evolutionary history, before transitioning to a phase dominated by packing of morphological space. However, this early phenotypic diversification is decoupled from temporal variation in evolutionary rate: rates of bill evolution vary among lineages but are comparatively stable through time. We find that rare, but major, discontinuities in phenotype emerge from rapid increases in rate along single branches, sometimes leading to depauperate clades with unusual bill morphologies. Despite these jumps between groups, the major axes of within-group bill-shape evolution are remarkably consistent across birds. We reveal that macroevolutionary processes underlying global-scale adaptive radiations support Darwinian and Simpsonian ideas of microevolution within adaptive zones and accelerated evolution between distinct adaptive peaks.
One will look in vain for evidence of positive natural selection in this paper. While bill size and shape are important to a bird, they are certainly not as important as flight. By choosing this one lesser trait to focus on, the evolutionists make their work easier, like saying, ‘To understand the evolution of automobiles, we will study the macroevolution of radiator grills.’ Even so, their evidence for macroevolution (when Darwinian theory is not assumed) is questionable. It must be emphasized that to distinguish evolutionism from creationism, evolutionists need to demonstrate changes beyond what creationists already accept. The most conservative creationists already allow for significant amounts of variability in bird beak sizes and shapes. That’s why they say ‘ho-hum’ to studies about Darwin’s finches, honeycreepers and vangas. They want Darwin to prove a dinosaur can take off into the air with muscle-powered flapping wings by natural selection alone.
Darwin’s ideas of microevolution are well known. These authors rely heavily on the ideas of a prominent 20th century Darwinist, George Gaylord Simpson. Cooney et al. explain Simpson’s ideas as they begin the paper, amplifying on what they said in the Abstract (above). First, however, they admit a major contradiction of predictions for macroevolution.
The role of adaptive radiations as the source of much of the world’s biological diversity has been widely emphasized. Studies of small clades have provided insights into the role of natural selection as a diversifying force, but cannot illuminate the processes that shape the diversity and discontinuities of radiations over longer evolutionary time frames. Indeed, at large taxonomic scales, the diversification of clades and traits shows no evidence of the predicted slow-downs in evolutionary rates, despite there being numerous examples in small clades. This apparent paradox is potentially resolved by G. G. Simpson’s model, in which major jumps to new adaptive zones (‘quantum evolution’) can occur unpredictably throughout clade history. These jumps give rise to rapid lineage expansion into previously unoccupied niche space as sub-clades continue to radiate within distinct adaptive zones and subzones. Simpson’s models introduced the concept of ‘mega-evolution’—diversification over large temporal and spatial scales—unifying microevolution with other factors such as ecological opportunity and evolutionary constraints that shape the macroevolutionary trajectories of radiating lineages.
It appears that Simpson discovered how flexible the Stuff Happens Law (SHL) can be as a theory rescue device. Isn’t that the plain meaning of this paragraph after it has been translated out of Darwinese? Simpson makes up a word, ‘mega-evolution,’ to cover up the lack of evidence for macroevolution. Darwin, though, had insisted that “Natural selection acts only by taking advantage of slight successive variations; she can never take a great and sudden leap, but must advance by short and sure, though slow steps” (Origin of Species, 1859). So when leaps and gaps become evident, one would think that would falsify Darwinism according to Charlie’s own standards. But Simpson turns that evidence into vindication for Charlie by applying the SHL. Some vindication, though! In his new book Darwin’s House of Cards, Tom Bethell points out the downside of Simpson’s rescue strategy:
George Gaylord Simpson (1902-1984), the curator of paleontology at the American Museum of Natural History and later at Harvard, once drew attention to the all-embraching nature of Darwinism, but did so as though it were a point in its favor. Animals from different lines can either converge, or evolve in parallel, or diverge, he said. Whatever happens, it “usually has an adaptive basis.” [Simpson, The Major Features of Evolution (1953), p. 171]
So evolution has all the bases covered. It is “opportunistic,” Simpson reassured us. What could possibly falsify such a theory?
Incidentally, Bethell knew Karl Popper personally. The father of falsificationism as a criterion for science told Bethell the following after it was widely reported that Popper had recanted his criticisms of Darwinism as a scientific theory.
I immediately brought up the issue of natural selection. He [Popper] told me that his opinion had not changed. He also said that he thought that natural selection had in fact been falsified “by Darwin’s own theory.” [Bethell, p. 15]
Getting back to the issue at hand (macroevolution of bird bills), Cooney et al. continue their vain quest to vindicate Darwin.
However, although phylogenetic studies involving thousands of species have demonstrated heterogeneity in rates of phenotypic evolution, it is unclear whether the processes outlined by Simpson have an important role in large-scale adaptive radiations. This is because previous studies have been unable to specifically assess the macroevolutionary dynamics of ecologically relevant traits. Here we study the evolution of an important ecological trait (bill shape) across an entire class of organisms (birds) to elucidate the processes shaping the accumulation of phenotypic diversity within a global-scale adaptive radiation.
Here’s how it works: ‘Evolution happens fast, and it happens slow. It jumps unpredictably. Stuff happens.’ Evolutionists can ramp up the perhapsimaybecouldness index to handle any contingency:
The disjunction between rates of evolution and the accumulation of bill-shape disparity suggests that temporal trends in evolutionary rate are not necessarily indicative of the underlying mode of niche filling. This decoupling could arise if some clades diverge rapidly within regions of morphospace that are occupied by other clades, but where the respective clades occur in allopatry….
[Last sentence]: It is likely that the rise of modern birds from the late Cretaceous onwards occurred in a rapidly changing world, coinciding with extensive ecological opportunity. Our results imply that this dynamic adaptive landscape may have driven Simpsonian mega-evolution across adaptive zones, later giving way to smaller scale fine-tuning of the bill as avian diversity expanded across the globe.
Translated from Darwinese, this means, ‘maybe stuff happens.’ Birds evolved fast except when they evolved slow (11/04/14). Cooney’s publicists in Nature (naturally) heap warm fuzzy praise for this glorious insight: “a large-scale study of bird beak evolution by Cooney et al., on page 344 highlights the importance of rare and even single events in the history of life,” writes Bhart-Anjan S. Bhullar. Strangely, he destroys Cuvier only to resurrect him. Georges Cuvier’s “catastrophism theory ultimately fell before the intellectually nuanced Darwinian idea that changes in the make-up of Earth’s flora and fauna have been continuous and uniform.” My, how times change. Darwin’s idea is not intellectually nuanced any more.
The researchers predicted that their data would be consistent with the concept of quantum evolution — the idea that an initial radiation involves rapid divergence into new forms and functions. For instance, such rapid divergence occurred during the Cambrian explosion of lineages of animals that have bodies showing bilateral symmetry, which began about 541 million years ago and lasted for 20 million to 25 million years. Under this model, rates of beak-shape diversification would be fastest during the initial avian radiation. Indeed, the authors found that most of the shape space filled rapidly during this initial burst. Coupled with a comprehensive study of avian relationships, which indicated that the radiation was associated with the catastrophic end-Cretaceous mass extinction 66 million years ago, these results support the idea that evolution is highly contingent on chance occurrences, marrying a Darwinian and a Cuvierian world view.
Incidentally, Darwin was greatly troubled by the Cambrian explosion, hoping it would be resolved as more fossils came to light (it wasn’t). And no, it wasn’t 20-25 million years long, but more like 3-6 million, a ‘geological blink of an eye’ comparable to one minute in a 24-hour day, explains Stephen Meyer in Darwin’s Doubt. It’s amazing how Darwinians can turn falsification into vindication, then use it to vindicate Darwin against additional falsifications. The SHL ensures their web of belief (2/11/17) can wobble safely between catastrophism and gradualism and back again without damage.
Some publicist Bhullar turns out to be. Look what he says about Cooney’s paper, then about the fossil evidence:
As with any pioneering effort, Cooney and co-workers’ study raises questions and would benefit from refinement. Despite covering more than 70 million years of evolution, for instance, the authors did not analyse any fossils, and thus did not explicitly take into account the historical record of avian evolution. As they point out, though, most fossil bird beaks are crushed. Moreover, the fossil record, at least superficially, supports the idea that a diversity of beaks was present soon after the end-Cretaceous extinction.
In other words, since bird beaks were already diverse when the assumed asteroid hit, the catastrophe might not have had anything to do with creating ‘ecological opportunity’ for natural selection to work its creative magic.
If all this fake science (storytelling, confabulation) is getting you down, maybe a look at some actual living birds would help. At least it shows what Darwin’s theory is up against.
Update 2/23/17: Just after this post was written, Nature published an article by paleontologist Stephen Brusatte about the evolution of birds from dinosaurs. In “A Mesozoic Aviary,” Brusatte destroys any scenario of dinosaurs evolving from birds in a straightforward Darwinian manner. His description fits the Stuff Happens Law. He calls that “interesting”—
The attainment of powered flight—that is, active flapping that generates thrust—has been widely regarded, sometimes explicitly but often implicitly, as a long evolutionary march in which natural selection progressively refined one subgroup of dinosaurs into ever-better aerialists. However, recent fossil discoveries reveal a much more interesting story that is beginning to be corroborated by biomechanical studies. According to this story, the development of flight was chaotic, with different dinosaurs experimenting with different airborne behaviors using different airfoil and feather arrangements (see the figure), until ultimately only modern birds survived.
One obvious comment: dinosaurs are not scientists. They do not run experiments. Brusatte claims that dinosaurs evolved wings and feathers “for nonflight reasons (such as display, egg brooding, or something else entirely) and that their early evolution was not shaped by selection for aerial flapping.” The catch-all phrase “or something else entirely” reveals he has no idea. Having abandoned scientific reasoning entirely for complete just-so confabulation, he continues:
Only much later, it seems, did some paravians evolve the right combination of small body size, large wings, and other anatomical features to begin powered flight. It was at that point that selection was able to mold these animals into more effective flying machines.
Having ratcheted up the perhapsimaybecoudlness index, he ends with the rescue device of futureware: “But much work remains to be done to better understand this heady period of evolution.” See Phys.org‘s summary of Brusatte’s commentary.
Update 2/24/17: The fossil of a giant penguin has been found “much earlier than previously thought,” reports Science Daily. Dating to 61 million Darwin Years, it means that penguins were already well diversified when dinosaurs roamed the earth. The previous record for oldest penguin was about 45 million Darwin Years. Were penguins swimming with ichthyosaurs? It’s hard to think of a bird more different from a land-based theropod dinosaur growing feathers trying to become airborne, than a flightless bird that swims underwater! How many mutations did that take? Another surprise is that this was a giant found in New Zealand, measuring 150 centimeters (5 feet), is as large as the biggest fossil penguin previously known. “This shows that penguins reached an enormous size quite early in their evolutionary history, around 60 million years ago,” the discoverer said.
“The discoveries show that penguin diversity in the early Paleocene was clearly higher than we previously assumed,” says Mayr, and he adds, “In turn, this diversity indicates that the first representatives of penguins already arose during the age of dinosaurs, more than 65 million years ago.”
Real Live Birds
Keas Perform Similarly to Chimpanzees and Elephants when Solving Collaborative Tasks (PLoS One). There’s a reason the cute but noisy parrots of New Zealand are so mischievous: they’re smart. In fact, one kea showed a preference for working with others instead of alone, a trait “present in humans but absent in chimpanzees.” How can the authors rescue Darwin from this conundrum of ranking bird intelligence with ape intelligence, despite their vast separation in Darwin Years? “This raises the possibility that aspects of the cooperative cognition seen in the primate lineage have evolved convergently in birds.” The authors did it by applying the Stuff Happens Law and raising the perhapsimaybecouldness index.
Wintering ducks connect isolated wetlands by dispersing plant seeds (Phys.org). About 34% of seeds that mallard ducks eat are passed through unharmed. “Surprisingly, they have very high site fidelity and return to the same sites almost every night,” the press officer from Utrecht University reports. This provides an ecological service for wetland communities. “Given the large numbers of seeds mallards ingest on a daily basis, they are likely to greatly contribute to plant dispersal and the connection between otherwise isolated plant populations across a wide range of landscapes.”
Emergence and development of gut motility in the chicken embryo (PLoS One). Illustra Media’s documentary Flight: The Genius of Birds animates the amazing 21-day process of embryonic development from egg to chick. This new paper discusses the complexity of one specific stage: when the intestinal tract begins to pulsate in the movements called peristalsis that will be essential for the developing chick when it hatches and eats its first food.
Departure of migratory birds from stopover sites is hormone-controlled (Phys.org). “Every year, billions of migratory birds make their way back to Europe from their wintering quarters,” this article says. “Since their energy reserves are not enough for a non-stop flight, they put in stopovers along the way to rest and replenish their fat stores. That migratory birds must stop on their long journey is clear. But how long they rest and what signals tell the birds to continue on their way has so far been unclear.” European scientists identified levels of one hormone, ghrelin, that appears implicated in appetite of warblers and their urge to migrate. Most likely, as in mammals, “a network of hormomes” regulates these functions.
Did complex flight feathers ’emerge’? (Evolution News & Views). This intelligent-design-based article critiques the propensity of evolutionists to concoct Darwin Flubber when evidence fails. The word “emergence” becomes their emergency rescue device when faced with explaining complex structures like flight feathers – and powered flight itself.
We need more translators of Darwinese into common-sense English. Are you getting good at it by reading CEH? Once you master the terms in Jargonwocky, you begin to see the SHL everywhere. You see evolutionists ratcheting up the perhapsimaybecouldness index. You know the difference between explanation and confabulation. You smell the vaporware of Darwin Flubber cooking in the lab. You no longer fear the DODO heads mumbling incomprehensible sophoxymorons, the moyboys spinning mythoids about Darwin Years as safety nets for Charlie, the DOPE heads in the schools imposing Darwin Sharia. (If any of these terms seem unfamiliar, see the Darwin Dictionary.)