Fossil record shoots down origin of flight just so story.

 Fossil Friday: A Popular Just-So Story on the Origin of Bird Flight Bites the Dust

Gunter Bechly

This Fossil Friday features the early bird Confuciusornis from the Lower Cretaceous of Liaoning in China. Last week I reported for Fossil Friday on a just-so story about ichthyosaur evolution and how it fell apart (Bechly 2023). This week I want use the opportunity to report yet another case of a popular evolutionist just-so story that recently was put to rest for good. It is about the origin of avian flight.

An Old Debate About Birds

There is a long-running debate in evolutionary biology, asking whether birds took off by running and flapping from the ground up (cursorial hypothesis), or whether they jumped as gliders from the tree down (arboreal hypothesis). About twenty years ago there was a modification of the cursorial hypothesis suggested by Dial (2003), based on the observation in chicks of living Chukar partridge: it is the so-called wing-assisted incline running (WAIR) hypothesis, which suggested that wing flapping lifts the body during uphill running. This was also claimed to answer the old question “What use is half a wing?” (Dial et al. 2006), which obviously is not just an iconic question Darwin skeptics came up with.

The WAIR hypothesis quickly became more and more popular, with dozens of studies published on various aspects, such as aerodynamics (Tobalske & Dial 2007, Dial et al. 2008), mechanics (Bundle & Dial 2003), kinematics (Baier et al. 2013), and computer modelling (Heers et al. 2018). “According to the proponents of the WAIR hypothesis, adaptation to WAIR in avian ancestors prepared their locomotor apparatus for the subsequent evolution of forward flapping flight. In other words, WAIR is proposed as a preadaptation to full-fledged avian flapping flight.” (Kuznetsov & Panyutina 2022)

The Function of Wing Flapping

However, last year a new study by Kuznetsov & Panyutina (2022) showed that, contrary to earlier beliefs, the function of the wing flapping during uphill running is not to lift the body, but to push it towards a steep slope. This is the opposite adaptation to powered flight and requires very different muscles. Actually, “it follows that the action of the forelimb during WAIR cannot preadapt the musculature in a non-flying ancestor to free flapping flight. Furthermore, the wing action during WAIR [already] requires highly developed avian flight musculature.”

Therefore, the authors concluded that “Wing-assisted incline running should be regarded as a crown locomotor specialization of birds and is not an appropriate model for locomotion in avian ancestors.” Unsurprisingly, there was not a shred of paleontological evidence for the WAIR hypothesis (Nudds & Dyke 2009), and non-avian feathered dinosaurs as well as early birds arguably were incapable of WAIR (Senter 2006), which is the opposite of the model’s prediction. It looks like yet another evolutionist just-so story bites the dust after empirical data failed to support the imaginative storytelling.

References

Baier DB, Gatesy SM & Dial KP 2013. Three-dimensional, high-resolution skeletal kinematics of the avian wing and shoulder during ascending flapping flight and uphill flap- running. PLoS One 8(5): e63982, 1–16. DOI: https://doi.org/10.1371/journal.pone.0063982

Bechly G 2023. Fossil Friday: Ichthyosaur Birth, Another Evolutionist Just-So Story Falls Apart. Evolution News September 29, 2003. https://evolutionnews.org/2023/09/fossil-friday-ichthyosaur-birth-another-evolutionist-just-so-story-falls-apart/

Bundle MW & Dial KP 2003. Mechanics of wing-assisted incline running (WAIR). Journal of Experimental Biology 206(24), 4553–4564. DOI: https://doi.org/10.1242/jeb.00673

Kuznetsov AN & Panyutina AA 2022. Where was WAIR in avian flight evolution? Biological Journal of the Linnean Society 137(1), 145–156. DOI: https://doi.org/10.1093/biolinnean/blac019

Dial KP 2003. Wing-Assisted Incline Running and the Evolution of Flight. Science 299(5605), 402–404. DOI: https://doi.org/10.1126/science.1078237

Dial KP, Randall RJ & Dial TR 2006. What use is half a wing in the ecology and evolution of birds? BioScience 56(5), 437–445. DOI: https://doi.org/10.1641/0006-3568(2006)056[0437:WUIHAW]2.0.CO;2

Dial KP, Jackson BE & Segre P 2008. A fundamental avian wing-stroke provides a new perspective on the evolution of flight. Nature 451(7181), 985–989. DOI: https://doi.org/10.1038/nature06517

Heers AM, Rankin JW & Hutchinson JR 2018. Building a Bird: Musculoskeletal Modeling and Simulation of Wing-Assisted Incline Running During Avian Ontogeny. Frontiers in Bioengineering and Biotechnology 6: 140, 1–25. DOI: https://doi.org/10.3389/fbioe.2018.00140

Nudds RL & Dyke GJ 2009. Forelimb posture in dinosaurs and the evolution of the avian flapping flight-stroke. Evolution 63(4), 994–1002. DOI: https://doi.org/10.1111/j.1558-5646.2009.00613.x

Senter P 2006. Scapular orientation in theropods and basal birds, and the origin of flapping flight. Acta Palaeontologica Polonica 51(2), 305–313. https://www.app.pan.pl/article/item/app51-305.html

Tobalske BW & Dial KP 2007. Aerodynamics of wing-assisted incline running in birds. The Journal of Experimental Biology 210(10), 1742–1751. DOI: https://doi.org/10.1242/jeb.001701

Humankind: Evolving with a little help from our friends?

 Intelligent Design in Human-Animal Friendships

Eric Hedin

Our experiences suggest strongly that many animals — mostly but not exclusively mammalian — possess an innate quality that enables them to relate to and connect with humans. Cats and dogs, our most common domesticated pets (estimated at 135 million in the U.S.)1, provide countless examples of the relationships that can develop across the human-animal divide. If the number of pets alone isn’t enough evidence of their importance to our lives, consider how much Americans spend on their pets — estimated at $136.8 billion in 2022.2

Considering the importance we place on our relationship with pets, what is our point of connection with them? A reasonable answer would be our shared qualities of mind, will, and emotions, or what could be termed “soulish” qualities.

Not Merely Animals

By drawing attention to the shared attributes between humans and animals that enhance our interactions, I am not suggesting that this supports any contention that humans are merely animals. Animals can relate to us by sharing certain aspects of a subset of our characteristics, but the overlap is far from complete. While animals share with us the quality of intelligence, we transcend them in significant ways, including our abstract reasoning, language and mathematical abilities, our unlimited creativity, and our ability to visualize and instantiate novel outcomes. Another notably unique human trait is our ubiquitous spiritual nature.

Spirituality is a significant and universal aspect of human experience. The specific content of spiritual belief, practice, and experience varies, but all cultures have a concept of an ultimate, transcendent, sacred, or divine force.3

Worship of the divine is not an observable behavior among animals.

“Winning” the Competition

Does our ability to relate to animals and their responsiveness to human interactions indicate intelligent design in the order of things on Earth? From an evolutionary point of view, human dominance among all species on Earth resulted from our “winning” the competition for survival of the fittest. In this view, an innate animosity could be expected to persist between humans and other animal species. 

Now, some Darwinian aficionados might object to this conclusion by appealing to the genealogical distance between humans and animals, arguing that “time heals all wounds.” If this is so, the soothing of ancient animosities has occurred so effectively that it has been replaced with a distinct inclination to relationship found between humans and many animal species. Interestingly, animals that are conducive to domestication by humans are those that support a mutually beneficial relationship with humans. 

But once domestication got rolling, we didn’t just change the animals we brought into our lives; they changed us, too. Humanity would look very different today — and possibly not have thrived to the extent that it has — without the assistance and support of domesticated animals to help us hunt, bear burdens, provide food and materials for clothing and tools, and so much more.4

Earliest domestication occurred with dogs (approximately 15,000 years ago)5, used in assisting humans with hunting; goats, pigs, and sheep probably came next (9,500 BCE), followed by cattle and horses, with their well-known, mutually beneficial relationships with humans.6 Other domesticated animals include some that might not immediately come to mind, including, chickens, guinea pigs, water buffaloes, pigeons, rabbits, and fancy rats.

Aside from the more utilitarian examples of domesticated animals used for food, bearing burdens, or transportation, the breadth of therapeutic human-animal interactions is profound.

The variety of possible types of interactions that occur between humans and animals results in an equally rich variety of effects on human health and well-being, including behavioral, educational, physiological, and/or psychological effects.7

Our pets provide us what is termed an affiliative relationship, and its benefits are familiar to most people. Even when I was in grade school, I can vividly remember the feelings of contentment and joy that I experienced when two little black kittens my family had recently acquired fell asleep in a purring huddle on my lap as I sat in the sunshine on the milk box on the back porch.

Pets entail a strong emotional attachment that facilitates the exchange of physical and psychological benefits. Pet ownership correlates with a number of health benefits, such as increased physical activity and lower baseline blood pressure (McCune et al., 2014).8

More targeted human-animal interactions have become popular in recent years:

Human-Animal Interaction encompasses many relationships with animals, including companion animals, emotional support animals, working animals, and any Animal-Assisted Intervention.9

An Extremely Wide Scope

The scope of human physical, emotional, and mental needs that are benefited by animal interactions is extremely wide.

Animals have been used in therapies for children with autism, adults with spinal cord dysfunction, older adults with dementia, and prison inmates.

Service animals are individually trained to help disabled persons overcome specific disabilities. They promote a more independent livelihood, facilitating, for example, mobility for the visually impaired, low blood sugar detection for diabetics, or support for veterans with post-traumatic stress disorder.

Human-animal interactions of all types elicit positive psychological effects in clinical and nonclinical populations across the lifespan.11

Futuristic depictions of human societies in science fiction movies and many books often portray a world without pets. Star Wars seems to have replaced animal pets with functional robotic companions — for example, the resourceful and intuitive R2-D2. Pets were conspicuously absent in the original Star Trek shows, but the crew shows the effects of their deprivation when tribbles pullulate aboard the Enterprise and the crew absolutely luxuriates in their company.

What is it about animals that gives us the positive benefits from our interactions with them? While human-to-human relationships are vital to our lives, sometimes our human relationships can get complicated. Animals relate to us in a refreshingly uncomplicated manner. We don’t feel judged by animals. They are rarely in a hurry. While they certainly have their own needs, they often seem to be able to sense when we have particular physical or emotional needs and their calming presence with the affection they give helps us towards well-being.

Many people whose lives have been enhanced by their interactions with animals (myself included) could hardly imagine a life devoid of such human-animal companionship. As evidence for intelligent design, the provision of animals that assist our lives in so many ways stands out as not merely fortunate, but profoundly caring.