Evolution Writ Small

One might think that the natural place to look for an understanding adequate to the evolutionary history of life would be the powers of self-transformation we observe in the evolving organisms themselves. But it can be dangerous to look in a clear-eyed manner at the creative potentials of living beings. One risks having to acknowledge the evident wisdom and agency so vividly on display. In an era of institutionalized materialism, any suggestion that these inner powers are vital to the entire evolutionary story can only produce the sort of discomfort associated with a taboo.

On the other hand, Stephen Jay Gould ran afoul of no taboo when he effectively ascribed this same wisdom and agency to natural selection. Countering the questions we heard voiced in Chapter 16 about what sort of creative principle could explain the “arrival of the fittest”, he asked (referring to several giants of twentieth-century evolutionary biology), “Why was natural selection compared to a composer by Dobzhansky; to a poet by Simpson; to a sculptor by Mayr; and to, of all people, Mr. Shakespeare by Julian Huxley?”

The answer, Gould said, is that the allusions to poetry, musical composition, and sculpture helpfully underscore the “creativity of natural selection”:

The essence of Darwinism lies in its claim that natural selection creates the fit. Variation is ubiquitous and random in direction. It supplies the raw material only. Natural selection directs the course of evolutionary change. It preserves favorable variants and builds fitness gradually.¹

On its face, this argument for Darwinism was a puzzling one. Its answer to the question how variation arises amounted to saying nothing more than “It is everywhere” (“variation is ubiquitous”) — which, one might have thought, only added urgency to the need for an explanation. The suggestion seems to be that, because organisms are so expert and prolific at producing new possibilities of life, the evolutionist can simply take their powers of achievement for granted without actually looking at them. Because organisms so abundantly provide what is needed (“raw materials”) for the transformation of life, we are somehow free to declare natural selection the transforming agent. It need only preserve all those wonderfully effective new variants, and they will somehow integrate themselves into the almost infinitely differentiated unity of a living being. We need not concern ourselves with those powers of integration and unity. After all, what could they have to do with evolution?

How easy it is, apparently, to forget that the so-called “raw materials” being preserved are never merely raw materials! At the first appearance of any substantive change, the creative work has already been accomplished — if indeed the change is truly beneficial to a living being. We find ourselves looking, not at random raw materials, but at a whole harmoniously transforming itself as a whole, where everything tends to affect everything else.

In this way, whatever we may have falsely isolated in our minds as a “new feature” is incorporated into the tightly interwoven complexity of an organism’s life. The only power we know to be capable of such incorporation is that of the organism telling its own story, a story always reflecting the qualitative, unified character and dynamic developmental potentials of a particular species.

This harmonious incorporation of new features, founded upon whole-cell inheritance and manifested in whole-organism processes of development, is where we see creative evolutionary change originating. The spreading of an already-existing change through a population is an entirely different matter.

So Gould’s response shows us that one of the evolutionist’s strategies for coping with taboo agency is immediately to turn the question, “How does creative change arise?” into the different question, “How does creative change, once arisen, spread through a population?” The switch of topics is not hidden, but occurs in plain sight. Only a habit of blindsight relative to the organism’s agency seems able to explain such an obvious evasion of a real biological question.

None of this means we need to doubt whatever is true in the idea of natural selection (which may be very little that bears directly on evolution). Selective mortality certainly occurs throughout all domains of life. Not every organism lives out a full life. But the mere elimination of problematic traits (or defective organisms) through mortality is not the same thing as positively and viably transforming the integral unity that a particular organism is.

The point is not terribly subtle. There is simply nothing in the idea of natural selection itself that points to the creative capacities necessary for producing new adaptive features — for producing, say, a four-chambered heart (with all its organism-wide implications) from a three-chambered one. There is only the living being whose agency and activity natural selection necessarily assumes and which evolutionists have unconsciously transferred to a mystical “mechanism” of selection somehow operated by the inanimate world.

So, if we do not accept this subterfuge, we are left with the main question for this chapter: What do organisms show us, directly, compellingly, and uncontroversially, about their own powers of organic transformation? Much of the first half of this book contributes to an answer, especially at the physiological and molecular levels of observation. But in the present, evolutionary context, it will be well to look at the organism from a new angle.

As researchers hone their ability to investigate single cells, they are finding that even neighboring cells, “identical” in type and occupying the same tissue or niche, reveal great heterogeneity. Every cell is, in whatever degree, “doing its own thing”.

Strikingly, however, the cell is not only doing its own thing; it is also heeding the “voice” of the surrounding context, which is in turn an expression of the unity of a particular kind of organism. So each cell is disciplined by the needs of its immediate cellular neighborhood as well as those of the entire developing organism, which in turn is conditioned by the larger environment. Every organism — even a single-celled one — is a remarkable diversity within an overall, integral unity.

In humans there are, for example, cells (neurons) that send out extensions of themselves up to a meter or more in length, while being efficient at passing electrical pulses through the body. There are contractile cells that give us our muscle power. There are the crystalline-transparent fiber cells of the lens of the eye; their special proteins must last a lifetime because the nucleus and some other subcellular entities (prerequisites for protein production) are discarded when the fibers reach maturity. There are cells that become hard as bone; as easily replaceable as skin; as permeable as the endothelial cells lining capillaries; and as delicately sensitive as the various hair cells extending into the fluids of the inner ear, where they play a role in our hearing, balance, and spatial orientation.

Many of these cells are as visibly and functionally different, in their own way, as the phenotypes of any two organisms known to us. This, you might think, would interest the evolutionary biologist. It has drawn the attention of a few who — if they do venture to comment about it — tend to be widely ignored on the point. One such is the much-awarded biochemist, cell biologist, and cancer researcher, Mina Bissell, who remarked in an interview with Cell magazine, “Your nose and mouth are completely different and yet they have the same DNA. So what on earth is telling the DNA what to do?” (Bissell 2020).

The question is as old as it is decisive. A hundred years ago, as we heard in Chapter 7 (“Epigenetics: A Brief Introduction”), the pre-eminent biologist, Frank Lillie, who served as president of the National Academy of Sciences, said that “those who desire to make genetics the basis of physiology of development will have to explain how an unchanging complex [DNA] can direct the course of an ordered developmental stream” (Lillie 1927, pp. 367-68). I can’t say there’s much evidence yet that evolutionary biologists feel they should bother with the question.

A gamete is at least as specialized as any other cell of the body. At the same time, this gamete, along with the entire lineage leading up to it, must retain the potential to yield the totipotent zygote. That is, despite its commitment to a highly specialized, reproductive function unlike that of any other cell type in the body, the germline cell must at the same time preserve within itself the flexibility and freedom that will be required for its role as progenitor for every cellular lineage of a new organism.

It is an extraordinary mandate, and our bodies must focus extraordinary powers of development upon it. For example, the chromosomes of both sperm and egg will have been modified by epigenetic “marks” (Chapter 7, “Epigenetics: A Brief Introduction”), ensuring that certain genes in the offspring will be active, or repressed, depending on which parent the gene was inherited from. Other widespread marks imposed by the parents will (for the most part) be erased immediately after fertilization. This leaves space for the new organism to structure the spatial, electrical, and chemical characteristics of its chromosomes (and therefore also its gene expression) according to its own way of being and developmental potentials.

And, of course, there is the elaborately orchestrated “meiotic ballet” (Page and Hawley 2003) that produces both sperm and egg, each with only half the number of chromosomes found in somatic cells, and with those chromosomes reshuffled and otherwise modified according to a logic and via activities that are still largely beyond any comprehensive understanding. But one thing is sure: the body’s rearrangement (“recombination”) of its germ-cell chromosomes during meiosis is now showing itself to be highly regulated. Multiple protein complexes and epigenetic modifications of chromosomes function combinatorially, with synergism, antagonism, and redundancy: “The new-found multiplicity, functional redundancy and [evolutionary] conservation” of these regulatory factors “constitute a paradigm shift with broad implications” (Wahls and Davidson 2012).

So we are given no choice but to think of the germline as an expression of that same agency — that same, end-directed transformative power — through which our bodies subtly, elaborately, and adaptively direct each of their other cell lineages toward a distinctive form and functioning within the unity of the whole. We have seen that this power of transformation comes to intense expression in entire differentiating cells, quite apart from any mutations in their DNA. And it is just a fact that an entire cell is what each parent passes on as an inheritance to its offspring.

It would be strange indeed if the organism’s ability to proceed adaptively and creatively along paths of whole-cell developmental transformation were to become frozen at the very point where, via the most sophisticated activity imaginable, it prepares its whole-cell bequest for the next generation. Can we reasonably claim that this is the one cell lineage in which the organism’s normal, future-oriented activity goes silent? Or that, with all the organism’s expertise at producing and stably maintaining diverse phenotypes even without changes in DNA sequence, it “refuses” to employ this expertise when it comes to the preparation of inheritances? Or that the power with which the organism adapts all its cells, tissues, and organs as far as possible to new or unexpected conditions is a power lost to it in the management of its own germline?

If every organism is a living agent and power of becoming, as we know it to be, then surely that power of agency — whatever its nature, and however conditioned and constrained by the material results of its previous activity — is the decisive thing preparing the way for a new life. And yet our science has not even addressed the problem of this species-specific formative power, let alone asked about its source or about what role its unfolding expression and its development of its own potentials might play in evolution.

The questions we do ask — and ask compulsively — have to do with how an organism’s genes mutate, not how, say, a mammal directs its single, inherited genome toward the radically different fates of a lens cell and a liver cell. Such cellular fates (not unlike the whole-organism fates of larva and beetle or tadpole and frog we also discussed above) are repeatedly and stably achieved before our eyes and with apparently casual ease, despite their being more complexly divergent over the space of a few weeks or months than the changes accomplished in a million years within many an evolutionary lineage.³

Another question we could wonder about is how all this creative potential of the organism bears upon the question of genetic mutation itself. And here we would have to reckon with the same future-oriented aspect we see in every cellular lineage during an organism’s development, and indeed in all biological activity. Which is to say that the real question hasn’t yet even been posed.

That question is not “How does a mutation affect this organism’s fitness”, but rather “How does it relate to where the species is going evolutionarily?” It cannot be emphasized enough that this latter question differs radically from that of fitness. After all, a tadpole in the process of transforming into a frog — having lost its tadpole organs for feeding and digestion, but not yet having completed the formation of the corresponding frog organs — is presumably not as fit as the fully mature frog. But this temporary “unfitness” is exactly what is required for the sake of a good future.

In her 1983 Nobel address, geneticist Barbara McClintock cited various ways an organism responds to stress by, among other things, altering its own genome. “Some sensing mechanism must be present in these instances to alert the cell to imminent danger”, she said, adding that “a goal for the future would be to determine the extent of knowledge the cell has of itself, and how it utilizes this knowledge in a ‘thoughtful’ manner when challenged” (McClintock 1983). Subsequent research has shown how far-seeing she was.

James Shapiro, a leading microbiologist and geneticist at the University of Chicago, worked for a considerable time with McClintock, and has himself gone a good way toward achieving her “goal for the future”. In his impressive and sprawling book, Evolution: A View from the 21st Century, he has painstakingly documented innumerable ways that organisms carry out what he calls “natural genetic engineering” on their “read-write genomes”. The relevant molecular biological research is rapidly intensifying today and throwing ever more light on the subject. We can be quite sure that Shapiro’s understanding will become more and more the “view from the 21st century. However, there is not much reason for me to recapitulate any of Shapiro’s massive work here, and I wish only to add one line of thought of my own.

As long as there has been a modern biological science, it has been common for biologists to mention in passing the “wisdom of the organism”. But this has hardly been a theme seriously influencing their scientific understanding, and I imagine that McClintock’s rather more tendentious references to the cell “sensing” danger, and to the use of its “knowledge” of itself in a “thoughtful” manner, has raised more than a few skeptical eyebrows in the years since her Nobel address. But what, really, is the issue here?

Do we not know that the DNA of a human cell suffers tens of thousands of lesions (“mutations”) per day, and that without the cell’s skillful and well-informed repair of nearly all this damage we would not long survive? Or that when germline cells undergo the cell divisions producing gametes, they routinely and competently restructure their genomes via a process known as “genetic recombination”? Or that all dividing cells pass through “checkpoints” at which they assess whether they have accrued enough unrepaired DNA damage to require a decision in favor of cellular suicide? Or that immune cells creatively reconstitute their genomes so as to enable the potential production of millions of distinct proteins required for immune activity — proteins that could not have been produced before the elaborate reconfiguration? Or that certain one-celled organisms (Deinococcus radiodurans) are capable of reassembling a functional genome after their chromosomes have been shattered into more than a thousand fragments by radiation (Chapter 8)? Or that topoisomerases — enzymes that cut one or both strands of a DNA molecule and then stitch them back together so as to release twisting tension or undo knots — do so with uncanny knowledgeability, so that their discoverer, Harvard molecular biologist James Wang, after calling the feat “amazing”, explained:

An enzyme molecule, like a very nearsighted person, can sense only a small region of the much larger DNA to which it is bound, surely not an entire DNA [molecule]. How can the enzyme manage to make the correct moves, such as to untie a knot rather than make the knot even more tangled? How could a nearsighted enzyme sense whether a particular move is desirable or undesirable for the final outcome? (Wang 2009).

And do we not know about the several hundred molecules that collaborate with surgical precision to remove parts of an RNA and splice together the remaining parts, typically preserving only a small fraction of the original molecule — all of which is accomplished this way rather than that way in order to produce the needed form of a protein under the current circumstances in a particular cell type (Chapter 8; Talbott 2024)? There are no mechanical linkages enforcing the outcome, and no instructions telling the diffusible molecules what sort of protein the larger context requires here and now. And yet, the molecular “surgeons” display all the expertise one could ask for. Do we have any idea how this expertise actually comes into play — or what part of our biological theorizing would remain if we only went as far as accepting the fact in front of our faces that it somehow does come into play?

Perhaps most importantly, do we not know of the technically overwhelming ways in which the whole cell brings all its intricately interwoven, almost infinitely complex regulatory resources to bear upon the expression genes — something I tried to give a slight hint of in Chapter 14 (“How Our Genes Come to Expression”)?

We certainly have a right to worry about McClintock’s use of words like “sensing”, “knowledge”, and “thoughtful”, which so strongly suggest something like consciously directed human activity. But, however we care to think about organisms lacking our sort of conscious self-awareness and powers of reflective thought, the effective knowledge is somehow, undeniably there. Unfathomably, as far as our current thinking goes. Freely moving molecules are guided moment by moment – not by any mechanism contrived in the past, but with what we can only think of as a practical understanding of the detailed nature of the current task and, equally perplexing, a firm grasp of the needs of the present context. What can we make of this, and can we really afford to ignore it?

Think about it for a moment. A superior wisdom vastly dwarfing any understanding we can consciously claim, is at work in all our bodily functioning. It’s a wisdom through which the body, early on, launches each of innumerable cells upon one of hundreds of perfectly targeted, altogether different, multi-generation journeys, each of which eventuates in a differentiated state of a highly specific character. Each journey is a venture into the future requiring all the cell’s resources, including its DNA, to achieve a whole-cell organization for which no roadmap or set of specifications is given in advance. And even if there were a map or set of explicit instructions, no one has any suggestion as to how molecules in the watery medium of a cell might be informed and guided by such instructions as they collide a million times every second with other molecules.

What we witness is not merely a set of complexly interwoven physiological processes impossible to encompass from moment to moment with our understanding minds. As an effective power, the wisdom of our bodies apparently acts (as you and I cannot in any conscious sense)⁴ at the root of material manifestation just as physical laws do. And so this organic wisdom is able to entrain lawful material performances within the current of its own higher intentions and meanings.⁵

We might have asked long ago: Could such a wise and knowledgeable power, intrinsic and prerequisite to our material being, possibly not be enlisted in service of the future evolutionary state toward which an organism, as a member of an evolving species, was being “called”? And can we reasonably think that mutations or transformations of DNA, with which the immanent wisdom of our bodies is already so deeply engaged, are the one aspect of activity around DNA that this wise power is clueless about?

If you are skeptical at this point, what do you make of the bodily wisdom that accomplishes so much that is incomprehensible to you?

Notes

1. Gould 1976. By the time Gould completed his 2002 masterwork, The Structure of Evolutionary Theory, he would offer a richly nuanced qualification of these statements. But his fundamental belief in the creative role of natural selection — or, as he would say, its “efficacy” — remained.

2. Figure 17.1 credit: Goliath beetle larva: Ximonic, Simo Räsänen (CC BY-SA 3.0); Goliath beetle adult: courtesy of Frantisek Bacovsky.

3. The organism’s ability to transform its cells (that is, to transform itself) independently of genetic mutations during development becomes especially significant when we consider those evolutionary lineages where change seems to occur at an unexpected, almost preternaturally rapid pace. See, for example, the discussion of cichlid fish evolution in the lake region of East Africa (Chapter 19, “Development Writ Large”). But we would expect germline DNA, over generations, to be caught up in a species’ self-transformation, just as are all other available resources. The main point is that DNA would not be the sole or leading factor in the change. It would, in its own way and like all the other parts, express the evolving whole, not govern it.

4. Actually, this is not true. We consciously move our own bodies, although we are not conscious of how it is done.

5. In this way our bodies show us in every detail of their activity why the supposed problem of physical determinism versus freedom is a falsely contrived problem whose solution stares us in the face every day. Every biological activity testifies magnificently to the fact that physically lawful interactions readily lend themselves to being caught up in larger, more fully meaningful performances. The laws of physics — which, we shouldn’t forget, are ideas — are themselves expressions of one kind of meaning in the universe. And, like all meaning, they can serve the expression of higher meaning.

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Steve Talbott :: Evolution Writ Small