evolution

by Robert DePaolo

Abstract

 

This article offers alternatives to Darwin’s theory of natural selection as a complete explanation of evolution. Two other possibilities are discussed, including a revision of Lamarckism. The argument is offered that while there is probably not a direct, imminent mutative response to environmental changes as in Lamarck’s model, a feedback mechanism might exist within the interactions of DNA, mRNA, protein synthesis vis a vis environmental shifts that induce organic stress and lead to a state of genomic agitation, (i.e. negative feedback) that creates uncertainty in biochemical assembly and over time increases the probability of trait mutations.

Topsy-Turvey Naturalism

Sometimes it seems the idea of randomness as applied to adaptation is hard for even Darwinian adherents to conceptualize, possibly because it is non-deterministic and perhaps a bit alien to scientists. Darwinian advocates often allude to…”organisms developing large molars to accommodate a vegetarian diet”, or perhaps…”a coat color mutation creating a blend with tall grass to facilitate stealth and predation.” The fact that natural selection could lead to random mutations that could be advantageous is not in question here. Undoubtedly that process occurs at some (trial and error) level of probability. Yet it seems incomplete.

Take tooth development. The notion that there is an implicit congruence between a vegetarian diet and having small canines and large molars implies several things that are sequentially confusing. One pertains to the question of whether certain creatures began eating plants, then evolved teeth more suitable to grinding or whether the mutation to smaller canines and enlarged molars came first, leading to a “decision” by the creature to shift to a plant diet. Since most creatures have brains, evolution can arguably never be separate from cognition – a point that will be revisited in the discussion on Neo-Lamarckism.

It raises other questions. For example; why would a creature change its dietary preference? If it never ate plants before the mutation; its taste buds, perceptual attractions, dietary tract, metabolism and behavioral instincts would have to change along with its teeth. If it did eat plants prior to the dental mutation why the need for large molars and small canines? If the creature had subsisted as a herbivore prior to the mutation what benefit would the tooth restructuring provide – bearing in mind that many primates with large canines feed primarily on plants, which after all are plants. With regard to the efficiency of tooth structure and plant eating, meat eating involves chunking morsels down as opposed to chewing but one could do that with lettuce as easily as with a leg of zebra.

Another problem with Darwin’s theory is his notion of sexual selection. In choosing mates females could certainly select some traits over others but that selection process might run counter to evolutionary change; not just because the meshing of paternal and maternal genes tends to stabilize the gene pool but because females typically select males with traits that represent the current state of the species. For example human females value language capacities in men, which happen to be unique to our species. Some female birds select males who sing well or those with elaborate plumage that exemplifies the best status quo traits of the species. In that sense sexual selection would seem to mitigate against evolutionary change. The females in any given species cannot be prescient enough to select mates with unusual traits that may or may nor prove advantageous down the road. They do not mate by chance but by purpose, which would tend to skew the evolutionary process toward species norms.

Another problem lies in the fact that the biological world and all its creatures operate by a homeostatic process. When there is a disturbance in any physiological system, the tendency is for cybernetic (corrective) responses to restore stasis. The fact that there are regulatory genes in the genome and also communicative interactions between RNA and DNA regarding the appropriate synthesis of proteins suggests homeostasis operates at the biochemical level. That suggests a holistic process in gene alignment rather than peculiarities cropping up here and there that would be subject to nature’s scrutiny.

Finally, there is the problem of chronology. Whenever an opponent of natural selection argues that it is impossible for the order and complexity seen in all organisms to occur over time the counter argument is that life has been around for well over a billion years and that humans cannot conceive of such extended time spans – that they can’t impose anthropocentric judgments on evolutionary probabilities.

In some ways that argument is legitimate, except for one thing. Evolution does not happen “over time.” It often occurs in short bursts – in other words it is punctuated. For most of those billion or so years, organisms did not change much at all. Then in dramatic spurts they did. Unless one assumes some cause and effect relationship between the relatively sudden change in the environment and an increased rate of mutation.

Alternatives

Based on such snags in the theory of natural selection, there are alternative ideas that would not refute Darwin’s theory but might augment, or even surpass it as a model. One, proposed by this author is progressive encoding (DePaolo 2007). To explain this requires a look back at the origin of life. Many have grappled with the question of how life began on earth, especially since even bacteria are incredibly complex, it is clear such systemic entities did not arise from spontaneous generation (Wald 1954) or from a floating DNA molecule that out-competed other macro molecules that did not replicate (Muller 1966) or from some sort of proto-biotic protein that could build somatic structures and also reproduce (Fox 1977). One question raised by Shapiro (2006) who wrote a very insightful book on the subject of origins was how a system comprising life – with its self sustaining and reproductive capacities cropped up in the first place.

Bits of Existence

Progressive encoding is based on Information Theory concepts. Without going too far off the subject, this theory can be whittled down to two main concepts. One element is noise, which is a super blend of elements without distinction, thus without information content. In simple terms, if every component in a whole is exactly the same there can be no identities within the structure thus no capacity to separate one item from another). Nor could any one element or the “super blended whole” have any capacity for communication because information transmission requires at least two separate signals.

The other component is information, or a code, which does feature distinctions that operate outside the overall “blend” and while interacting with it, are not incorporated into the whole. As an illustration; consider a room full of people who all look exactly alike, have the same exact name, walk and talk exactly alike. In such an instance there would be no personhood. On the other hand if one person “broke loose from the pack” found a way to talk and look differently and assigned himself a separate name those distinctions would comprise three bits of information. One bit (or distinction) being unique language, a second bit pertaining to a distinct appearance, a third resulting from his having a unique name.

Information can be quantified. The general formula is that each resolution of noise or uncertainty (undoing of the blend) comprises one bit of information (Shannon, Weaver 1949), (Pierce 1961), (McGliece 2002). One interesting aspect in this scenario is that despite being differentiated from the others the “information man” would still have to interact with the others. If he remained isolated he would eventually become himself a monotonous system with no distinction or information content. He would regress toward a “noisy” blend. Thus the influence of information dynamics in nature is sequential and mandatory. A component can break out of a uniform system, become informed/encoded but to remain solvent it must interact with other components or systems that in turn are distinct from it, lest it lapse into a insular state of noise, i.e. entropy.

Yet that process has a major snag. Any system that expands and becomes more interactively variable will run the risk of chaos. In order to maintain the integrity of the overall system there must be interactive rules, that is, a governor. In the hypothetical social example discussed above the rules might revolve around a common language, and perhaps rules on social probity. In the body the rule is homeostasis i.e. an oversight process that recognizes errors in the overall system and can summon substrate organs to make readjustments regarding body temperature, blood flow, caloric count, metabolism, cellular maintenance etc.

From People to Molecules

The proto-biotic molecules on earth poised potentially to ratchet into life forms were faced with a “noise” problem. Such molecules no doubt cropped up periodically in some sort of assimilable form, but due to disruptive lightning storms, water flow and extreme shifts in temperature between day and night they would break up and re-blend with the surrounding milieu. In order for life to evolve into a system with anchor point structures and functions required a mechanism by which it could separate from its surroundings; specifically a semi-permeable membrane. Membranes insulated cells from the tumult of the outer world and enabled them to function independently. The advent of the first semi-permeable membrane did not allow for complete independence but rather created a capacity to remain separate yet communicate with the environment so it could absorb and discard energy and obtain and act upon information about the outside world. Membranes consist of lipids, which are fats. Fats provide an ideal insulation against water and other agents. With their incorporation into the cell structure came a new process of evolution, characterized not just by natural selection but by an increasing tendency toward organic insulation. First, came membranes to insulate the cell proper. Then with the advent of eukaryotic cells came nuclei and other organelles to provide further layering between the inner and outer world. And as organisms proceeded to become larger and more complex came further insulation in the form of organ structures with specialized functions, such the alimentary tract, lungs, (or gills), muscles, hearts and brains.

The advent of separate and distinct organs led to an increase in bio-information content. An important aspect of information content (even in a biological context) is redundancy. By way of explanation, the main purpose of all biological systems is cellular integrity. Cells need nutrition (including oxygen) to survive. Having lungs to inspire, a heart and vessels to pump and transmit, muscle to burn sugars and signal the need for replenishment creates a very efficient division of labor that insulates the organism against a failure in any one system and increases the odds on cellular survival. In short, the number of layers (distinctions/bits) in the body provides both increases insulation from the environment and a parallel increase in bio-information content. In that context the amount of information contained in any given organism delineates its separation quotient from the environment and correlates highly with adaptation and survival.

Snags in Complexity

According to Progressive Encoding Theory life did not merely emerge and evolve as a retroactive means of adapting to its environment but also as a means of avoiding environmental influence through the complexity of organic structural and functional insulation – in other words via enhanced information content. The progressive encoding process provided organic stability, complexity, inter-organic communication/cooperation and also produced a template by which organisms could continue to get larger, more internally complex and poly stable.

While speculative, this concept could be used to explain why mammals became homeothermic and why humans developed a brain capable of imaginative cognition. Being able to interact covertly through imagination, anticipatory thought and planning might have been just another step on the progressive encoding sequence that insulated us yet further against the influence of the outside world. This might have been a continuation of the rudimentary noise reduction process that created the initial separation of cell from environment and it might help explain why human brain expansion enabled us to create the separate, non-experiential and insular worlds of art science, empathic morality and politics. In other words the same mechanism that made life’s onset possible was also responsible for the paintings on the Sistine Chapel.

Another Alternative

Even if progressive encoding can be viewed as a co-causal process in organic evolution it is probably not the only complementary factor. This author is fond (in an ironic sort of way) of statements by dyed in the wool scientists that either personify basic biological phenomena or state them in deterministic language. For example Richard Dawkins (1976) and Carl Sagan (1980) both alluded to the idea of the “selfish gene”; the idea being that mere macromolecules are capable of instructing organisms on how to behave and think; all for purposes of maintaining the gene pool. The dictatorial qualities they assign to genes is interesting on many levels. First it implies that an entity without mind is controlling entities with minds (begging the question of what brains are for in the first place). Second, it suggests subjects like morality, social cooperation, sexual interest, even the use of deceptive behavior are driven by molecules; the rest of our bodies oblivious enactors of plans drawn up in the primordial soup several billion years ago. Perhaps we haven’t changed much after all.

At face value the selfish gene concept might seem dubious. Then again haven’t biologists discovered the highly communicative interactions between mRNA, DNA and protein synthesis? Is it not the case that chemicals correct errors, set up complex chemical pairings on the double helix, perform editing functions via RNA interruptions and tell protein composites how and where to line up in gestation? All these well documented functions do exist. Turns out many of the decisions we consider cognitive occur in the smallest of contexts. That leads to discussion on a newly emerging concept of evolution based on the initially refuted theory of Jean Baptiste Lamarck.

The Origin of Theory

Jean Baptiste Lamarck was one of several early thinkers on the subject of evolution. His model, often referred to as “soft inheritance” or “use/disuse” theory held that organisms evolved traits in response to environmental pressures. Unlike Darwin he saw organic change as more purposeful than purely accidental. The key element in his theory was not that individual organisms could change in the face of environmental pressures but that such changes could be passed on to subsequent generations. One flaw in his mode was the notion that evolution inevitably proceeds to order – that there is an implicit (almost Platonic) drift toward organic perfection. That was a bit too anthropocentric for most scientists. The purposeful adaptation vs. random change distinction is important because it is well known that any given creature can alter its morphology in response to environmental changes. A thin person living in cold climates can “fatten up’ by eating certain foods and by becoming less active – two mechanisms for sustaining energy reserves. The real question is whether such changes can be carried over to new generations. In other words, will the person’s newfound girth and metabolic shift show up in the body type or metabolism of his offspring?

Early research seemed to disprove Lamarck’s theory; the most notable being Weismann’s study (1889) which showed that cats whose tails were severed did not over several generations produce tailless offspring. However in hindsight this and other studies seem suspect. For example severing tails in an artificial, experimental context had nothing to do with extant environmental pressures occurring over time. The experiment did not include environmental pressures mitigating the need for tails – as for example if long tails over time made the cat more susceptible to predation, i.e. easier to catch.

Weismann’s refutation prevailed in any event and natural selection remains a mainstay of evolution theory. On the other hand science never stands still and recent research has led to a modification of use/disuse theory in a new model supported by the idea of epigenesis.

Softer Inheritance

Based in part on questions regarding natural selection by Gauthier ( 1990) an others, Neo-Lamarckian theories have arisen, with roots in several areas of study. All of these models adhere to the notion that traits acquired in light of environmental changes can be passed on to subsequent generations. All of these are refutations of the germ plasm theory, which derives from natural selection and holds that the somatic experiences of one individual or generation will not register with the DNA and consequently are not heritable. Studies in the field of trans-generational epigenesis have shown that cellular and physiological traits that do not correlate with changes in the DNA sequence are heritable by daughter cells. (Jablonka, Lamb (1995), (Jablonka 2006). That would seem to challenge the idea of an exclusive connection between genes and mutations. Their study showed that altering the diet of mice with dietary supplements led to changes in expression of the Agouti gene, which is involved in color, weight and cancer proneness. Thus it seems generational changes can transfer to the traits of offspring even without changes in the genetic code.

Other studies have offered challenges to the natural selection model. For instance the functions of stem cells as macro-generators of more specific cells raises questions about the direct link between specific genes and inherited traits. (Skinner 2015) In this instance changes were determined by stem cell generativity without a corresponding change in the DNA of specific traits. Offering still another challenge to natural selection, are “prion” studies which have shown that proteins can catalytically convert and reduce a protein’s activity and that micro-RNA can cause a delay or disruption in the communication between messenger RNA and protein synthesis (Krakauer, Zanotto et al 1998). In a sense epigenetics turns the entire concept of evolution upside down. It not only brings into question the legitimacy of natural selection theory but also offers an alternative mechanism on how traits are passed on.

Quite obviously the simple notion that genetic mutation, superimposed on environmental change determines which traits emerge and which organisms survive is a bit lacking as a complete explanation. Still, it is not a model easily abandoned, in part because of its simplicity. The question is: where does one find a good fit among the progressive encoding, epigenetic and natural selection models?

Feedback

A key element in evaluating evolutionary thinking lies in the concept of feedback. In a sense the epigenesis studies demonstrate that on some level a feedback/registration mechanism does exist between the outside world, the genes and the soma. It seems the genome (ancient and unmalleable as it might seem) is aware of an organism’ response in light of environmental pressures. Yet evolution is such a long term process that one must explain exactly what happens in that interaction; In other words if genes can change in response to the environment why would this only occur over after millions of years or in punctuated manner during dramatic environmental shifts?

One possible resolution is to assume, in line with the progressive encoding theme, that environmental changes can, over time cause genomic discord, featuring disturbances in the alignment process in the form of negative feedback between organs and genes which leads to disturbances in the pristine structure of the genetic code. If the genome and soma do communicate with respect to prolonged hormonal, anatomical and physiological duress might it begin to quaver a bit, producing noise in the system? Furthermore, might the noise go unresolved for long periods of time, perhaps exacerbated so much during environmental disasters such as glaciation, or volcanic-induced shifts in terrain that the amount of noise increases that genetic restructuring is made more rapid? In other words, with greater genomic discord do mutations reduce so much noise as to produce a leap forward of manifest traits by the thrust of emerging information content?

Looking at evolution in information terms allows for the implied purposefulness seen in epigenetic studies. In some sense this idea is reminiscent of Freud’s tension reduction theory, in that the organism can be viewed as a physical system governed by homeostasis. If feedback communications between genes and soma do exist, then the genes, “concerned” as they are with survival and propagation of the pool would tend to process threats to that mandate.

One way to prove or disprove an information-based model of evolution would be through research; specifically around the question of whether dramatic or prolonged environmental changes correlate with increased errors in genetic/molecular alignment, skewed reactions in mRNA or proliferation of discard genes that appear to have no influence in trait manifestation, but can signify an increase in noise in the genomic system. If such a cause-effect tumult can be proved to exist, there might be a theoretical shift beyond the scope of natural selection and epigenesis toward an information-based model of evolution that assumes environmental shifts, increased organic duress, an increase in somato-genetic uncertainty can lead to an increased probability of evolutionary change. If so, then perhaps, Heisenberg’s description of Information Theory as the “theory that decides” might prove accurate.

 

REFERENCES

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