Evolution for the Birds: Must Adaptation Be Evolutionary?
Darwinians use adaptation and evolution almost interchangeably. Is that justified?
Adaptation, strictly defined, refers to the matching of an organism to its environment. Think of a woodpecker. Its claws enable it to cling to tree trunks, and its tongue can reach into deep holes in the wood. The tongue, moreover, has a sticky tip able to glue onto bugs inside the hole. Its head is protected from the hammer-like blows of its beak, which is pointed for penetrating wood. The woodpecker, all would acknowledge, is well adapted to its lifestyle. A hummingbird, by contrast, has specific adaptations for hovering in the air while sipping nectar in flowers, including its nectar-trapping tongue.
Such amazing matches of organisms to their environment have been observed for thousands of years. Only since Darwin, however, has the word included linkages to evolution by natural selection. At Dictionary.com, two of the biological definitions embed natural selection in the definition of adaptation:
- any alteration in the structure or function of an organism or any of its parts that results from natural selection and by which the organism becomes better fitted to survive and multiply in its environment.
- a form or structure modified to fit a changed environment.
- the ability of a species to survive in a particular ecological niche, especially because of alterations of form or behavior brought about through natural selection.
This gives Darwinism an unfair advantage. It would be like defining oxygen as ‘anything that was produced by phlogiston.’ Embedding a theory into the definition of an effect thought to be produced by the theory is an example of circular reasoning, because other explanations are possible. Engineers, for instance, adapt parts to the needs of particular car models. An SUV needs a transfer gear box that a sedan does not. The parts of a Ferrari engine are adapted for speed; the parts of a truck for weight bearing. When evaluating claims in science articles about adaptation, perceptive readers should watch out for the assumption that adaptations were brought about by natural selection (the Stuff Happens Law). Here are some examples from the world of birds.
Inexperienced preys know when to flee or to freeze in front of a threat (PNAS). Observation: chicks do not need to learn about threats, because they instinctively know to flee or freeze when a threat appears. That’s the adaptation. It’s obviously important for survival. How do these three biologists explain it? “…it is expected that evolutionary pressures have equipped preys with mechanisms to counteract predators in different situations.” Why must the pressures be evolutionary? A pressure and a mechanism are very different things. It’s absurd to imagine that applying pressure to a chick will cause brain software to appear by chance. “Solving the long-standing issue of the evolutionary origins of antipredatory behaviors, these findings suggest that the adaptive needs of young preys are matched by spontaneous threat recognition and use of appropriate defensive mechanisms that do not require learning.” Why must the adaptive needs have evolutionary origins? The authors don’t mention any mutation for this trait that was “selected” by a Darwinian process. Necessity may be the mother of invention, but inventors have minds.
Why are bald eagles such great gliders? It’s all in the wrist (Phys.org). Wings show remarkable matches to the habitats and lifestyles of different birds. That part is uncontroversial. What does this have to do with evolution? The explanation in this article makes it sound like birds are choosing the mutations that the mystical Stuff Happens force will select to let them explore new niches. But what if they always were well matched to their habitats and lifestyles?
An enduring mystery is why bird species with similar flight styles or body sizes don’t have consistent wing shapes. All hummingbirds, and some species of falcons, hawks, kingfishers and passerines can hover, but the birds have strikingly different morphologies and are only distantly related. Ravens soar like eagles while their look-alike cousins, crows, stick more closely to the ground.
New research in Science Advances helps explain why. Bird species tend to reshape the range of motion of their wings—rather than wing shape or size itself—as they evolve new ways of flying.
The picture of Evolution as an engineer gets even more ridiculous further down: “Evolution has tested a range of wing designs and motions for specific circumstances.”
Why Do Pigeons Bob Their Heads? (Live Science). Parents will enjoy telling their kids in the park why pigeons bob their heads as they walk. There’s actually a reason for it. The bobbing gives pigeons the best possible amount of time with a stable gaze between bobs. Nice adaptation! What’s evolution got to do with it?
Pigeon’s eyes can move around like ours, but the birds also have more-mobile heads than humans do, so it makes sense that they’ve evolved head-thrusting as a more effective vision-stabilizing tool.
Reporter Emma Bryce lacks the sense to know that evolution has no sense. It’s mindless, remember? And birds could not evolve a trait by force of will any more than a human can grow wings and fly just by wishing for them.
Evolution is resetting the annual clock in migratory birds (Phys.org). German ornithologists have found that certain migrating birds, particularly flycatchers, seem able to adjust their biological clocks to changing climate. That’s the adaptation. The article claims that the Germans have”shown there is an evolutionary response of this clock to climate.” Why must it be an “evolutionary” response? What if that adaptive response is built-in to the birds’ software? Dr Barbara Helm responded, “The good news is that there is more adaptive potential than we previously thought.” Adaptive potential is not evidence for evolution, nor does it contradict intelligent design. Good programmers can write software that can handle multiple unforeseen circumstances. That’s how the Mars rovers know not to drive off cliffs, and know how to reduce power during the night.
Male mating displays can evolve from exploitative origins to cooperative endings (PNAS). Assuming adaptation is produced by selection can lead to humorous theory rescue attempts. In this commentary, Richard Gomulkiewicz does his best to rescue evolution from observations about ring dove mating displays that do not fit Darwinian natural or sexual selection. His attempt relies heavily on a high perhapsimaybecouldness index:
Species like the ring doves, however, are pair bonded and effectively offer no variation in the number of mates a male can have each season. This excludes sexual selection as an explanation for their exaggerated mating displays. Instead, male displays appear to stimulate female investment in reproduction. From an adaptive evolutionary standpoint, this is unexpected since a male’s efforts would be better spent contributing resources directly to his offspring and the female would be better off ignoring such displays if her investment in the brood is already optimal. When a male displays to a receptive female, the stimulation may cause her to overinvest in the offspring, imposing an immediate benefit to the male and future cost to the female. This is a form of sexual conflict, in which traits favored in one sex harm the other. In PNAS, Servedio et al. show that evolution can result in male displays that stimulate receptive females to invest optimally in their offspring; that is, evolution can convert sexual conflict into cooperation. Some have speculated that this reversal is logically impossible, but Servedio et al. prove otherwise.
DODOs in the Tree
Birds are not the only kinds of organisms that have Darwin-Only Darwin-Only (DODO) explanations thrust on them. Humans and their presumed bacterial ancestors all get the circular massage.
Accounting for diverse evolutionary forces reveals the mosaic nature of selection on genomic regions associated with human preterm birth (bioRxiv). This preprint by a team that includes Antonis Rokas, who tweaks evolutionary rates to keep Darwin from hurting (15 May 2013), starts off with circular reasoning in the very first sentence: “Human pregnancy requires the coordinated function of multiple tissues in both mother and fetus and has evolved in concert with major human adaptations.”
The treacheries of adaptation (Science). This is a surprising article. Craig R. Miller discusses a new idea by Johnson et al., who say that adaptation reduces the fitness of offspring! The steepness of a fitness landscape, usually concave in shape, expresses the cost of adaptation. An organism stuck on a fitness peak may have only one way out: down. Miller also explains the problems of epistasis: the reality that mutations interact in unpredictable ways. One beneficial mutation may be accompanied by one or more deleterious mutations. These ideas are problematic for Darwinism; Miller offers an escape hatch, saying that “The authors speculate that increasing costs, paired with the reality of diminishing gains, may arrest adaptation before a fitness optimum is reached.” Stuff Happens to the rescue! For our present purposes, suffice it to say that Miller assumes that adaptation is produced by natural selection. What if it isn’t? What if the adaptation was already there?
You’ve witnessed a major reason why evolution wins by default: scientists just assume it. The late Phillip Johnson saw through this gimmick in the late 1980s and 1990s. It was a major reason for the rise of Darwin skepticism, and on the other side of that coin, the rise of intelligent design as an alternative. In 2011, in a tribute to Johnson by Michael Behe on the 20th anniversary of his consensus-shaking book Darwin on Trial, Behe wrote,
Twenty years ago Darwin’s theory seemed a truism, simply because rival explanations had been ruled out of bounds from the start. Then Phillip Johnson’s epic Darwin on Trial cut to the heart of the debate. It wasn’t about evidence; it was about assumptions. And like the proverbial drunk looking for his car keys, no one searched beyond Darwin’s lamppost. Two decades later, even as scientific advances accumulate, Johnson’s insight remains key. We must cast off arbitrary assumptions. If we are ever to arrive at the solution[,] the search for answers to the question of how life arose and developed has to be free to follow the evidence wherever it leads. (Evolution News & Science Today).
Recommended Resource: Casting off arbitrary assumptions, Randy Guliuzza has offered a creation-supportive explanation for adaptation from an engineering perspective. His series on ICR about “engineered adaptability” and “continuous environmental tracking” is well worth pondering, because it’s based on a cause we know a lot about: intelligence.