October 10, 2023 | David F. Coppedge

Humpty Darwin Totters on the Wall

The reign of natural selection theory has long
been tenuous and may be nearing collapse

 

— Can all his horses and all his men save King Charley from a big fall? —

Humpty Darwin sits on a wall of foam bricks held together by decayed mortar. Cartoon by Brett Miller commissioned for CEH. All rights reserved.

About that Natural Selection Superpower

Darwinism is almost synonymous with “natural selection” (NS). In textbooks, the popular press and science journals, NS is the driving force that brought the world giraffes, whales, and human brains—indeed, everything in biology.

Since Darwin, his disciples in the Darwin Party have subcategorized selection into things like positive, negative, stabilizing, purifying, and balancing selection, kin selection, multilevel selection and more, but only “positive selection” matters. Only the positive selection of beneficial variations can lead to novelty, innovation or adaptation (see 2 Sept 2019; also P.J. Levi at Evolution News, 2011). Darwin’s mythical blind “Selector” takes rare beneficial mutations, according to the concept, and confers survival on organisms while everything else has to die (the “cost of selection”). The mutations or variations, moreover, are acknowledged to be random; that part is all chance. Only positive selection is claimed to drive evolution onward and upward with some kind of direction (“fitness” whatever that is).

Everything the Darwin Party believes rests on this tipping point: the validity of natural selection to create novel, functionally adaptive traits. How solid is the point? It supports a mythical city of subdomains, including astrobiology, the RNA World hypothesis, evolutionary psychology, and much more. On his wall of natural selection, is Humpty Darwin wearing a seat belt?

A few have challenged the supremacy of NS from time to time, but they have been largely ignored due to the reputation of Darwin built by scientific materialists and the media. That reputation took some decades to build, since many of his contemporaries criticized natural selection. By the early 1900s, the reputation was built, reinforced at the Scopes Trial, and became dominant with the rise of Neo-Darwinism (the “Modern Synthesis”). For a few decades criticisms were barely noticeable. Peace, however, was not to last.

Rumblings from Within the Scientific Materialist Camp

Kimura proposed a “neutral theory” in the 1960s that claimed most mutations are not adaptive. Neutral mutations do nothing to improve an animal. Levi begins with an alternative proposed by Austin Hughes in 2007, called the “plasticity-relaxation-mutation (PRM) model” but it never gained traction. In 2019, Stephen Talbott urged biologists not to begin with natural selection, and explained his doubts for its efficacy (15 Nov 2019). Proponents of the “Third Way” of evolution have also not yet succeeded in gaining much notice in the popular science media or Big Science journals. Some alternatives have looked almost comical in their mysticism, like Doolittle and Inkpen’s ITSNTS proposal (3 April 2018), which was prompted by their misgivings about the nature and power of NS (2 April 2018).

The Darwin Party remains in power, but tremors on Humpty Darwin’s wall have never stopped. Some new rumblings, published this month in leading pro-Darwinist journals, are worth noting. In each case, the authors rush to assure the public that all is well in Darwin’s kingdom, but their defensive rhetoric cannot ignore the concerns expressed by critics of NS.

Darwin or Kimura – Natural Selection or Pure Chance? (Senckenberg Institute of Biodiversity, 9 Oct 2023). The German defenders of Darwinian NS in this press release call defenders of Kimura “Neutralists” and defenders of Darwin “Selectionists.” What’s notable here is that they don’t completely refute the Neutralists, but try to reconcile the two.

Even within the group of “Neutralists”, opinions on this matter may differ, as the study authors point out. Some suggest that neutral mutations mainly occur in the non-coding part of the genome (e.g., ‘junk-DNA’), which has no effect on the appearance or functioning of an organism. Others suggest, instead, that neutral mutations are also common in the functional part of the genome (e.g., genes), and hence do cause phenotypic differences.

“The first position is fully compatible with Darwin’s concept of speciation by natural selection, while the second offers at times a potential alternative explanation,” explains the study’s lead author, Dr Menno de Jong of the Senckenberg Biodiversity and Climate Research Centre. “We refer to these different interpretations as the narrow and the extended versions of the Neutral Theory, because in the second case the Neutral Theory is extended to the phenotype. Kimura originally advocated the narrow version, but eventually accepted the extended version.” Even Darwin – more than 100 years before Kimura proposed the Neutral Theory – did not rule out the possibility that ‘variations neither useful nor injurious’ (Origin of Species, chapter 4) could manifest themselves over time as visible differences within and between species.

Menno J. deJong and colleagues argue that the two parties are not far apart.

De Jong and his co-authors stress that “Neutralists” do not reject the idea of evolution by selection. For instance, Neutralists do not question whether giraffes acquired their spots through natural selection. They only advocate neutrality when it comes to more subtle differences, such as the exact shape and size of the spots that characterise the different giraffe species and subspecies, says De Jong. “Proponents of the selection theory and the narrow version of the Neutral Theory will assume that each fur pattern evolved to fit the respective regional environment, while Neutralists adhering to the extended version of the theory may argue that the precise details of fur colouration do not offer significant survival advantages.”

See? Everything’s fine. Peace.

Moderating the neutralist–selectionist debate: exactly which propositions are we debating, and which arguments are valid? (deJong et al., Biological Reviews, 24 Aug 2023). This is the paper expounding on the ideas mentioned in the press release.

Brownian Darwinism

Long-Term Lizard Study Challenges the Rules of Evolutionary Biology (Georgia Tech, 9 Oct 2023). This press release begins with questions about “the paradox of stasis.” If NS is so powerful, why do animals and plants appear to survive unchanged for vast periods of time?

Charles Darwin said that evolution was constantly happening, causing animals to adapt for survival. But many of his contemporaries disagreed. If evolution is always causing things to change, they asked, then how is it that two fossils from the same species, found in the same location, can look identical despite being 50 million years apart in age?

Everything changed in the past 40 years, when an explosion of evolutionary studies proved that evolution can and does occur rapidly — even from one generation to the next. Evolutionary biologists were thrilled, but the findings reinforced the same paradox: If evolution can happen so fast, then why do most species on Earth continue to appear the same for many millions of years?

A display of the ‘living fossil’ coelacanth in England. From Wiki-Commons.
The term ‘living fossil’ was originally coined by Charles Darwin. From Wiki Commons.

Again, these authors rush to stabilize Humpty Darwin on his wall by addressing the paradox.

This is known as the paradox of stasis, and James Stroud, assistant professor in the School of Biological Sciences at the Georgia Institute of Technology, set out to investigate it. He conducted a long-term study in a community of lizards, measuring how evolution unfolds in the wild across multiple species. In doing so, he may have found the answer to one of evolution’s greatest challenges.

“We call this a paradox because it doesn’t seem to make any sense,” Stroud said. “The most common explanation is that natural selection is working to stabilize a species’ appearance, with the assumption that an average form will help them survive the best. The problem is, when people do field studies, they almost never find that this kind of ‘stabilizing’ selection actually exists.”

So if stabilizing selection isn’t defeating natural selection, why are animals exhibiting stasis? Stroud figured that “A Picture of Evolution Is Worth a Thousand Lizards,” so off into the jungle he went, lassoing lizards and watching them for three years. His conclusion?

Evolution can and does happen — it’s this ongoing process, but it doesn’t necessarily mean things are constantly changing in the long run. Now we know that even if animals appear to be staying the same, evolution is still happening.

It’s there. It’s happening under the hood. You just can’t see it.

Fluctuating selection maintains distinct species phenotypes in an ecological community in the wild (Stroud et al., PNAS, 9 Oct 2023). Stroud’s Darwin Rescue Plan made the cover story of the Proceedings of the National Academy of Sciences. With three colleagues from other American universities, Stroud set out to debunk the myth of the “paradox of stasis,” at least for three species of Caribbean lizards within a three-year period.

The observed patterns of natural selection on these co-occurring species can translate to community-wide patterns. Specifically, our results revealed that this lizard community occurs on a complex, rugged fitness landscape, whereby divergent niche specialists occupy independent fitness peaks. Fitness valleys inhibit evolutionary change and thereby can preserve community structure through time. Evidence from the fossil record has long suggested that entire communities may experience such “coordinated stasis”, yet this concept has attracted debate, due in part to an incomplete understanding of the processes that might drive it. While similar patterns of community structure could arise from alternative processes that are neutral to selection, such as developmental constraints or habitat tracking, here, we show that contemporary natural selection can be integral to maintaining patterns of community structure through time. In this case, the rugged fitness landscape that matched predictions of selection-driven community-wide stasis was only evident when measured over an appropriate timescale. We show that the combination of dynamic short-term bouts of selection (Fig. 3), whether within or between generations, can yield a cumulative selection landscape (Fig. 2) that is capable of maintaining species’ mean phenotypes through time.

The rescue plan seems to be saying, “natural selection is always working” but its effect might consist of “maintaining species’ mean phenotypes through time.” But how can this account for the appearance of new organs, like eyes, wings, and human brains? Is his explanation like Brownian motion, a random shuffle only evident through a microscope? NS is busy on the “rugged landscape” of fitness peaks, but if the valleys “inhibit evolutionary change,” nothing significantly new will evolve. The species of lizards he looked at for three years remained the same species. He admits this:

15 to 20 myo fossils closely resemble the extant phenotypes of modern ecomorphs, and phylogenetic analyses suggest that communities of anole ecomorphs have occurred in their present configuration over a similar time scale. Our results imply that this community-wide stasis may have resulted from stabilizing selection maintaining species on largely invariant peaks on a rugged adaptive landscape over macroevolutionary time, each peak corresponding to a different ecomorph phenotype.

But he didn’t witness macroevolution. Nothing changed in his observations; no speciation (“origin of species”) or innovation. The lizards looked the same. What did he really observe? Stasis! “Stabilizing selection” (which is not the driving force needed for upward evolution by positive selection) kept the community of lizards largely unchanged.

The adaptive landscape provides a conceptual bridge between microevolutionary processes and macroevolutionary patterns, unifying how natural selection can drive observable patterns of diversity from single species to entire communities. Nevertheless, as selection has rarely been measured in multiple coexisting species, community-wide adaptive landscapes have remained largely metaphorical. Our uncovering of a complex, multipeaked adaptive landscape bridges this divide, showing how natural selection can maintain species as divergent phenotypes through time and compound to produce community-wide patterns of species diversity. However, patterns of selection at microtime scales can be unpredictable: Selection can fluctuate dramatically from bout to bout—even differing among species at the same time—yet cumulatively produce patterns consistent with stabilizing selection.

He did not see a bridge. He saw only a conceptual bridge—a figment of his imagination. It is hard to see how Stroud has defended Neo-Darwinism in any way. He has just embarrassed the Darwin Party by admitting that most studies on adaptive landscapes “have remained largely metaphorical.” He criticizes stabilizing selection on the micro scale, but defends it on the macro scale:

The presence of local fitness optima within species, and fitness valleys between species, presents a barrier to adaptive evolutionary change and acts to maintain species differences through time. However, instead of continuously operating stabilizing selection, we found that species were maintained on these peaks by the combination of many independent periods among which selection fluctuated in form, strength, direction, or existence and in which stabilizing selection rarely occurred. Our results suggest that lack of substantial phenotypic evolutionary change through time may be the result of selection, but not persistent stabilizing selection as classically envisioned.

His explanation of NS sounds like Brownian motion: lots of commotion under the microscope, but when you back away, everything looks stationary.

These papers both show Darwinism in a very unstable state. If this is the best that Darwin’s defenders can do to keep him on the wall, his fall is coming soon, and nobody will be able to put him together again.

German authors of the first paper create a false dichotomy. They assume that Kimura’s Neutral Theory is based on “pure chance” but Darwinian NS is not. If “selection” is blind, unguided and purposeless, then it is just as chancy as mutation. That’s why we call Darwin’s theory of NS the “Stuff Happens Law.

Stroud’s paper pretends to stabilize Humpty Darwin on the wall, but actually gives him a shove. If stabilizing selection overcomes natural selection on the macro scale, then no macroevolution will occur. Imagine playing rugby on a mountain peak that has an uneven surface with a group of blind players. There’s lots of commotion; amidst the “fluctuations” in “form, strength, and direction” between players (who don’t know what they are doing and don’t care anyway), some players temporarily end up on little high points on the peak. Natural selection wins! But the players are never going to get the ball on top of a higher peak miles away. The valley below will keep them from “evolving” over there (which would represent macroevolution).

Both ideas are silly. To critics who mock, “You just don’t understand evolution,” we reply that more likely we understand it better than its own proponents do. Look at these papers, published triumphally in major Big Science journals by PhDs dedicated to Darwinism. Stroud’s paper made the cover of one of America’s leading journals. Did deJong or Stroud give you any confidence that this mythical concept of “natural selection” is capable of turning wolves into whales, Ediacaran fronds into trilobites, or monkeys into men with brains capable of building spaceships and computers? If so, we’d like to sell you a timeshare on the Isle of Debris.

 

 

 

 

 

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