Below is a brief summary of some of the main players in this rather un-Darwinian alternative evolutionary synthesis & a bit about their theories. Click on the image above for the more in-depth version from the forthcoming book: Evolution: A Scientifically Guided Thought Experiment – Book One: By Other Means…?
(1860 – 1948)
Thompson was born the year after Darwin published his famous book On the Origin of Species and in time, came to publish his own quite famous book: On Growth and Form, 1917 [Link].D’Arcy Thompson 1945 Link.
Fig. 2: Transformation of coordinates in ape compared to human skull. Source: ‘About D’Arcy’ Web site Link
On Growth & Form
After easily transforming our coordinate diagram of the human skull into a corresponding diagram of ape or of baboon, we may effect a further transformation of man or monkey into dog no less easily; and we are thereby encouraged to believe that any two mammalian skulls may be compared with, or transformed into, one another by this method. There is something, an essential and indispensable something, which is common to them all, something which is the subject of all our transformations, and remains invariant (as the mathematicians say) under them all. In these transformations of ours every point may change its place, every line its curvature, every area its magnitude: but on the other hand every point and every line continues to exist, and keeps its relative order and position throughout all distortions and transformations.
―D’Arcy Thompson (1942, American Edition reprinted 1945,
p., 1085) Link
Figure 2 above, is given as an analogy by D’Arcy Thompson to help visualise Nature’s flexibility and pattern of growth. They are used mainly by D’Arcy to draw attention to the fact that Nature makes transformation in a highly efficient manner by metaphorically stretching and skewing key origin/starting points (along the fundamental axis of growth on all planes) which changes the whole form in relation to everything else. The details are the filling in or, building up the contours patterns at different scales of the whole. In other words, if D’ Arcy Thompson had access to 3D computing software, he would have been able to input a few simple coordinates and equations/parameters and hit ‘RUN’. He would have produced very different shapes from the same basic template form by simply shifting the orientation (skewing or deforming slightly) the grid prior to the main contour details being filled in.
For instance, Figure 2 shows that the jaw area in an ape and the sloping brain case compared to the human skull. The human skull illustrates that much of the flexible sheet area is filled by the much larger brain-case compared to the grid area for the entire jaw. It is just the opposite in the ape skull example, where the grid is almost entirely filled by the massive jaw area and conversely, the grid area occupied by the brain-case are minimal.
On Growth & Form
From this comparison of the gorilla’s or chimpanzee’s with the human skull we realise that an inherent weakness underlies the anthropologist’s method of comparing skulls by reference to a small number of axes…But it is, in the first place, evident that these axes are merely the principal axes of a system of coordinates, and that their restricted and isolated use neglects all that can be learned from the filling in of the rest of the coordinate network”
―D’Arcy Thompson (1917,. 1084) Link
Overall, the outward appearance of the great diversity of even a single species is rather superficial according to D’Arcy Thompson as seen in the example give below in Figure 3 of the fish.
Fig. 3: Transformation of coordinates change the basic shape in every direction proportionally to itself (after D’Arcy Thompson 1917, figs 525-526). Link
Knowing the coordinates on his two idealised axes, Thompson was able to work out the third axes as it was on a predictable pattern. In many ways, he was working in 3D space in his mind, but he could only show these in a rather limited way in 2D. By metaphorically bending and stretching the flexible grids, he observed that these always grew (in magnitudes) scaled up or down in spatial arrangements in proportion to the whole.
Since Thompson’s time, much research has taken place, particularly within embryological studies, that lend good support to his observations of shape and formation of an organism and how this can be applied to describing species development. The best way perhaps to think of the grid analogy in three dimensions, it to visualise a bar magnet creating fields of attraction, or repulsion, or no effect at all. We can’t see the field, but we know it is there from its effects on iron filings. Indeed, if we had enough iron filings and moved these bar magnets around at different 3D grid points, we could change, and sculpt these into many different forms.
Essentially, D’Arcy Thompson’s growth and development grids in many ways represent what has come to be known as the morphogenetic developmental field, which I will explain using the quote below. But first, to explain what such a field, it is perhaps best visualised as being analogous to the patterning field created by a powerful magnet on all points of a 3D hollow sphere and the unorganised analogous iron filings are within. The metamorphic biological field is similarly known by its effects, (like a the force-field of the magnet aligning and arranging the filings) as it cannot be directly seen, but its effects are seen in the patterning and spatial layout of bodies during development which are described in the following science paper: Morphogenetic fields in embryogenesis, regeneration, and cancer: Non-local control of complex patterning by Michael Levin with an opening quote as follows:
…. A Question of Pattern
Emryonic development results when a single cell (the fertilized egg) reliably self-assembles a highly complex pattern appropriate to its species. This process is known as morphogenesis—the establishment and creation of 3-dimensional anatomy. During later life, multicellular creatures must maintain their pattern—an active process of morphostasis that works to maintain the whole while individual tissues age or are removed by traumatic injury. Some organisms replace large-scale structures during adulthood, illustrating the remarkable plasticity and dynamic control of shape by biological systems. For example, salamanders can regenerate eyes, limbs, lower jaws, hearts, and portions of the brain.
Levin (2012, 1) Link
Another important aspect of Thompson’s observations of growth and form was the concept that: a small change at the beginning can lead to a very big change further down the line. Imagine if D’Arcy Thompson had access to 3D graphic software, he might have been able to make endless variations on the same fundamental shape/form by slightly adjusting the initial starting conditions.
This idea of initial staring conditions causing a profound change further down the line, is a well-known concept established by observation within developmental evolutionary biological studies, but interestingly, it is also a well established and observable fact of physics and can be mathematically described. It is a principle within the specific field of Chaos theory, a branch of physics that tries to understand the tendency of systems to become disordered or chaotic and conversely, systems that seem disordered initial, tend to organise themselves. You may have heard of it – it is called the butterfly effect. It is explained in the MIT Technology Review When the Butterfly Effect Took Flight by Peter Dizikes (February 22, 2011) Link
This concept came about as a result of trying to study the very unpredictable and highly complex system (seemingly chaotic and without pattern and certainly with limited predictability – the weather. The problem was that when numbers were rounded off and put into a computation machine to project the outcome of the weather, the actual rounding up of numbers rather than using all the smaller numbers after the decimal place was believed to have no effect or a very minimal one to the end result. However, this very minuscule change at the beginning led to wildly different results depending upon the starting conditions. Therefore, it was given the analogy of a butterfly flapping its wings on one continent could have the potential to create a hurricane in another continent further down the line and coined the butterfly effect. However, as unpredictable as the weather is, it turns out that biological systems are slightly easier to understand and it may all relate to Nature’s incredible ability to be highly efficient and space-saving.
… the dynamic influence of starting conditions lies in the morphology of shells and horns. These are the permanent, non-living, three-dimensional record of a temporary, two-dimensional living state – the base of the horn, or the mantle of the shellfish. D’Arcy Thompson showed that all horn and shell morphologies could be described in simple mathematical terms readily derived from the incremental nature of growth.
… For instance, geometrical rules of packing determine cell arrangements. These need not be specified, but can arise spontaneously. Yet the packing arrangement may be “useful” in minimising the space occupied by the cells, by maximizing cell-cell contacts, by establishing different categories of cells (“inside” versus “outside”), and so on…
Perhaps the most famous images from ‘On Growth and Form’ are the transformations. D’Arcy showed that gross variation in form between related species could be modeled by the consistent deformation of a sheet.
The consistency of the deformation is the crucial point here: it is obvious that any fish form could be made to look like any other fish form, if it were sketched on a perfectly deformable elastic sheet, and stretched in many directions at once. But D’Arcy Thompson showed that if the sheet were stretched in one particular pattern, then a new species form would be generated. This remarkable and curious observation has not been fully explained even today.
This concept applied, means that even a minor change in the conditions of a developing species may and indeed, seems to have had a profound effect upon how it evolves and what it evolves into in the end. This aspect of D’Arcy Thompson’s research as well as his general principles regarding growth and development as it relates to an alternative form of evolution of the species is summarised above on the website dedicated to the man and his research:
As he observed the principles of self-similar repeating patterns on different scales of magnitude (we would describe these today as fractal) and he measured them and found that they had predictive and quantifiable proportions which for any mathematician or physicist, is a joy to behold. Moreover, he recognised the universality of these simple constants or invariant qualities throughout the natural world.
For instance, he was impressed by the fact that although biological forms differ widely, that the mathematics to describe them remains the same. Thompson didn’t just describe and catalogue all the natural patterns seen in nature, but explained their simple underlying properties that linked and was common to all. He even had a mathematical description for certain spirals (self-similar patterns) as seen in the form of many shells and applied what he called a logarithmic spiral to these predictable forms. These and many other shapes in nature had the property of never-changing its essential shape, once it was initiated; no matter how large or small, the equation was scaled up or down and still applied.
In essence, D’Arcy Thompson’s identification of the simple mathematical equations which underpin the outward complexity of biological life and according to its scaling, or fractal reiterations (repeating self-similar patterns built up in ever more complex detail on every dimensional plane). And as noted above, the great variations upon these themes, may have come about simply in accordance with their initial starting conditions and by following the scaling rules of growth and form which are discernible within Nature.
From his writings, it also appears that D’Arcy Thompson believed from his insights into natural systems (animate or inanimate), the principle of one part being reflected in the whole and that each part was mutually dependent upon an influenced by environmental effects. Thompson pondered this seemingly strange order of nature and noted that the underlying principles of order – were somehow universal and guided incredibly efficiently, the function and this informed its shape and form and while growing, developing or evolving, keeps everything in perfect proportion to itself. This led him to proclaim:
There is something, an essential and indispensable something, which is common to them all.
NASA (1999, May 28th) (Link).
In other words, none of this was just about pretty patterns and interesting mathematical abstractions, but these had very real applications. It meant that predictions about otherwise unknowable biological complexity could be discovered. Indeed, Thompson’s observations have been picked up in more recent times by NASA scientists who are using his book of life to find extraterrestrial life as seen below. On the NASA website the article is entitled: ‘Who Wrote The Book of Life? Picking Up Where D’Arcy Thompson Left Off’
NASA scientists are using Thompson’s biomathematical studies of life forms on Earth to postulate about life forms throughout the universe. There are certain universal conditions that will always affect the shape of a life form, wherever that life may be.
“Everywhere Nature works true to scale, and everything has a proper size accordingly,” wrote Thompson. “Cell and tissue, shell and bone, leaf and flower are so many portions of matter, and it is in obedience to the laws of physics that their particles have been moved, moulded and conformed.” … Gravity, for instance, acts on all particles and affects matter cohesion, chemical affinity and body volume. Other influences that are consistent throughout the universe are temperature, pressure, electrical charge and chemistry.
Yes, I noticed that NASA didn’t use Darwin’s On the Origin of Species on their cosmic missions. Anyway, D’Arcy Thompson’s ideas and concepts are definitely finding more recent scientific verification of late. Obviously, these universals of growth and form that Thompson and others proposed are powerful generalisations as they can allow us to effectively see into the otherwise unknown. These bigger principles highlight the underlying properties or biological organisms, which can explain in more simple terms, otherwise, seemingly inexplicable complexity. However, D’Arcy Thompson went further than simply highlighting these patterns of growth and form, but he also came to see it has having consequences for the way we viewed evolution of the species.
For instance, he states the following regarding this proposition which he offers as an alternative to the Darwinian view, which at that time was certainly not accepted as dogmatically as it is today (Darcy writes in his book published in the 1940s: and also note that protozoa refer to the entire kingdom of animals, and quadrupeds are four-limbed animals).
Eighty years’ study of Darwinian evolution has not taught us how birds descend from reptiles, mammals from earlier quadrupeds, quadrupeds from fishes, nor vertebrates from the invertebrate stock… Our geometrical analogies weigh heavily against Darwin’s conception of endless small continuous variations; …Our argument indicates, if it does not prove, that … the “higher” protozoa, for instance, may have sprung not from, or through one another, but severally from the simpler forms; or that the worm-type, to take another example, may have come into being again and again.
—D’Arcy Thompson, On Growth and Form, (1942, 1093-1095). Link
D’Arcy not only offered an alternative to the Darwinist model of evolution as he believed he seen a different means of it happening: springing not from a few or single origins, but from many forms that come into being naturally through the forces of nature and diverge from the earlier forms via the same agencies (shared forms with continuous variations and overlays of the same themes according to dynamic natural and universal laws of growth and form), but also because he seen much that was wrong with the Darwinian model of his own time and indeed even in the genetic age.
For instance, his issues with Darwinism, and indeed, many scientists of the time had issues with it, D’Arcy as seen in a paper that he wrote in 1894 entitled: Some Difficulties of Darwinism which is unfortunately not available as it was never apparently published, where we could see more regarding his view of the difficulties with Darwinism, but there is a link to its summary given by an unknown author, in Biology at the British Association, in Nature, Vol. 50, 1296 (1894) p. 435. (Link). There is however, a fairly good discussion in his 1942 American Edition of On Growth and Form: Vol. 1, The Rate of Growth and the discussion of embryology. Interestingly, this edition and the few reprints thereafter are the most extensive of D’Arcy Thompson’s work in containing 1116 pages, the most illustrations and much updated discussion based on evidence that had emerged since his 1917 edition Link
In the section: Of Physics and Embryology, he discusses issues with Darwin’s model that he believes the understanding of Von Baer’s work (see summary of Von Baer further on in this article) and morphology in general would resolve and it wasn’t slow either. Historically, there are very specific reasons for alternative views to the Darwinist model of evolution not surviving into our present era, but one particular reason that was emerging at the time of D’Arcy’s research that is worth highlighting here, that may have hindered his type of research, was that the broad and multidisciplinary approach (where scientists from different fields of physics, mathematics, embryology and the biological sciences, as well as anthropologists could use their disciplines and expertise to investigate the broader issues of life itself), was becoming increasingly difficult as science departments and scientists became more and more specific in their fields with little or no collaboration between them. This issue is clearly highlighted with some frustration by D’Arcy in Transformations: The Visual Influence of D’Arcy Thompson:
D’Arcy passionately believed in giving students as great a breadth of
knowledge as possible, telling them if you dream, as some of you, I doubt not, have a right to dream, of future discoveries and inventions, let me tell you that the fertile field of discovery lies for the most part on those borderlands where one science meets another. There is a cry in the land for specialization. . . but depend upon it, that the specialist who is not reinforced by a breadth of knowledge beyond his own specialty is apt very soon to find himself only the highly trained assistant to some other man. . . Try also to understand that though the sciences are defined from one another in books, there runs through them all what philosophers used to call the commune vinculum, a golden interweaving link, to their mutual support and interpretation.
Jarron (2013, 83-4). Link
In other words, as D’Arcy tried to relate to his students, there is a bigger picture to be discovered on the borderlands of science and getting distracted in classification and details only clouds the issue as noted a number of times by D’Arcy and as he noted above and in his other writings reveals that this extreme specialisation makes one blind to the greater discoveries. Thankfully, in our more modern era, this is beginning to change. This is seen particularly in the collaborations of scientists such as: Geoffrey West (a physicist working on biological problems in collaboration with other scientists from different fields of biological research) who echoes similar sentiments to D’Arcy as seen in an interview entitled: Yeah, but what about the crayfish? (…Where, the title is a reference within the article to how some biologists still show concern about details of animals rather than the bigger and more overarching patterns embedded in the natural world.
A different mind set
“In general,” … “although this was not true of my collaborators, biology tends to be dominated by a certain type of person in the opposite way to physics. They are always looking at the particular, and everything is an exception.” … [West] does not understand how such people can work in science if they do not believe there are such things as universal laws. “If you had biologists working, for example, in nuclear physics you would have someone working on deuterium and then someone else working on helium and they would not realize they were working in the same field.”
―Cartlidge (2001 – Physicsworld)
And another quote, this time from West’s collaborator Brown as taken from another interview with West and Co., entitled: Of Mice and Elephants: A Matter of Scale:
”Physicists tend to look for universals and invariants whereas biologists often get preoccupied with all the variations in nature,” Dr. Brown said… Dr. West liked to joke that if Galileo had been a biologist, he would have written volumes cataloging how objects of different shapes fall from the Leaning Tower of Pisa at slightly different velocities. He would not have seen through the distracting details to the underlying truth: if you ignore air resistance, all objects fall at the same rate regardless of their weight.
Johnston (The New York Times dated to Jan 12th 1999)
All in all, D’Arcy Thompson’s desire for a broader approach to the bigger questions in many ways is beginning to re-emerge. Moreover, the collaborations of such scientists and their multidisciplinary approach has led to the discovery of exciting, predictable patterning in Nature that can be summarised in powerful, yet simple equations and actually begin to give us a deeper insight into the underlying processes that begin to explain the predictable scalable unity of D’Arcy Thompson’s observations of shape and form.
Geoffrey West and others noted above are also beginning to find answers in the universal patterning of life as seen in the following statement by West:
”Everything around us is scale dependent,’’…
”It’s woven into the fabric of the universe.”…
”It is truly amazing because life is easily the most complex of complex systems,’ …. ‘But in spite of this, it has this absurdly simple scaling law. Something universal is going on.” …
—Johnson (New York Times Jan 12th 1999)Link
This of course expresses the very same sentiments of D’Arcy Thompson, once he got a mathematical insight into the amazing predictability and universality of Nature’s systems. And interestingly, the research of West and others is being taken quite seriously even by biologists such as: Richard Dawkins as noted in a recent interview below:
A different mind set
The work has drawn praise from many biologists, including the popular science writer and Oxford professor Richard Dawkins, who describes it as “a theory of enormous power, explaining a huge range of facts with great economy”.
Cartlidge 2001, July, p. 3: A Different Mindset). Link
Perhaps, I should point out at this stage, that although, the more recent collaborations between physics and biology have at least recognised and acknowledged D’Arcy Thompson’s contributions to revealing the deeper complexity of biology, they take the cautionary approach to stating these laws and invariants of scale and form in more general and less emphatic terms than D’Arcy Thompson did as indicated below:
Life’s Universal Scaling Laws
Although few today would articulate Thompson’s position so provocatively, the spirit of his characterization remains to a large extent valid, despite the extraordinary progress during the intervening century. The basic question implicit in his discussion remains unanswered: Do biological phenomena obey underlying universal laws of life that can be mathematized so that biology can be formulated as a predictive, quantitative science?
Most would regard it as unlikely that scientists will ever discover “Newton’s laws of biology” that could lead to precise calculations of detailed biological phenomena. Indeed, one could convincingly argue that the extraordinary complexity of most biological systems precludes such a possibility. Nevertheless, it is reasonable to conjecture that the coarse-grained behavior of living systems might obey quantifiable universal laws that capture the systems’ essential features. This more modest view presumes that, at every organizational level, one can construct idealized biological systems whose average properties are calculable.
West and Brown (2004, 36)
Therefore, we could go one of two ways here and either acknowledge that even in the light of our more modern approaches to trying to understand biological complexity, D’Arcy Thompson’s model is still highly relevant; albeit as an idealised concept and useful for grasping the essence of biological systems and how they appear to work. On the other hand, we could take the position that D’Arcy Thompson took, based upon a much broader approach to the most up-to-date evidence from many fields of study and apply them to biological systems and restate his universal patterning of life in terms of biological laws that hold at every level in Nature.
I have taken the latter approach and as you will see: his dream of placing biology en par with the mathematical descriptions afforded physics and chemistry really do appear to hold across the entire spectrum and at every scale of life. They are quantifiable and predictable, not just descriptions of life, but a key to unlocking many of its mysteries embedded in the evolutionary process itself. In my mind, this is good science, as these laws and equations of scale can be tested and applied to find out things we could not otherwise directly measure.
Read more about D’Arcy Thompson’s theory in the preview version above and how it is proving highly testable and is turning out to be a very powerful explanation of the most fundamental processes embedded within all of Nature…This brings us to Alan Turing and his own particular mathematically based contribution to the understanding of evolutionary complexity via his theory of the chemical-basis of morphogenesis.
Alan Mathison Turing
THE TURING ENIGMA
MORPHOGENESIS AND THE OTHER CODING SYSTEM of LIFE
Alan Turing certainly did take his cue from D’Arcy Thompson’s mathematical challenge that Nature was knowable by observing her rules. And as presumably, like Thompson, Turing was also an amazing mathematician with a fascination for the natural world, of course, Turing rose to the challenge.
You see, Alan Turing is perhaps better known for his pioneering work during World War II for cracking the Enigma Code (Holehouse 2012) [Link], rather than his code cracking abilities as applied to biology, as seen in his publication entitled: The Chemical Basis of Morphogenesis (1952) [Link].
Essentially, where D’Arcy Thompson explained the underlying simplicity and universality of shape and form – transformations and scaled principles of the formation of the species, Turing showed how the bio-chemical properties and the context during development of the cells could create these meaningful pattern, shape, form and transformations of structures in the first place.
Turing was right all along
Turing’s equations of life, like D’Arcy Thompson’s mathematical description are not just numeric abstractions, but could help explain the natural development processes as will be seen below. Indeed, just as D’Arcy Thompson’s concepts of evolutionary processes are gaining wider acceptance due to a deeper understanding of biological complexity, so are Turing’s ideas.
For example, the great diversity of complex patterning, shape and form seen within the animal kingdom may be underlain and explicable by simple principles of bio-chemistry operating within and between cells that can be expressed mathematically as highlighted in an article by Holehouse, dated to the 20th February 2012 in the Telegraph: entitled: How did the leopard get its spots? and with the subtitle: Codebreaker Alan Turing was right all along [Link].
And, this subtitle, of course, is where this present section heading was derived. Again, more recently, Turing’s theory of Morphogenesis is highlighted as becoming increasingly well supported in the light of our deeper understanding of biological complexity as noted in another excerpt article outlined below:
Turing’s theory of morphogenesis validated
Scientists from Brandeis University and the University of Pittsburgh show how identical cells differentiate.
Alan Turing’s accomplishments in computer science are well known, but lesser known is his impact on biology and chemistry. In his only published paper on biology, Turing proposed a theory of morphogenesis, the process by which identical cells differentiate, for example, into an organism with arms and legs, a head and tail…
Turing was the first to offer an explanation of morphogenesis through chemistry. He theorized that identical biological cells differentiate and change shape through a process called intercellular reaction-diffusion. In this model, a system of chemicals react with each other and diffuse across a space — say between cells in an embryo.
These chemical reactions need an inhibitory agent, to suppress the reaction, and an excitatory agent, to activate the reaction. This chemical reaction, diffused across an embryo, will create patterns of chemically different cells.
Burrows (2014, 10th March)
For further detail and increasing validation of Turing’s theory of Morphogenesis, I would suggest viewing the video presentation given by Prof. Philip Maini and entitled: Turing’s Theory of Developmental Pattern Formation from the University of Edinburg dating to 2012 [Link].
Turing’s mathematical equations can be applied directly to biological processes during early cellular and embryonic development known as Morphogenesis, recall all the while the morphogenetic field that guides the meaningful expression of shape and form and the proposal from D’Arcy Thompson, that with a simple shift in these invisible growing fields (axes), approximating our more modern understanding of the morphogenetic developmental field, the same underlying form can, via deformation, become radically different in the end as seen between a gorilla’s skull and that of a modern human illustrated example.
Essentially, Turing’s model begins to explain how cells that start out as ‘un-programmed’ stem-cells or pluripotent cells, even though they all contain the same genetic code, can be ‘programmed’ chemically according to their growing environment. After programming, these cells would all have their specialised jobs relating to the function of a whole organism; it is this evolutionary process that actualised the meaningful proportions, patterning and formation of biological systems and seemingly has ultimately has helped modify, shape and form organisms according to their growing/developmental environment and therefore is implicated in the adaptation of the species itself.
Turing’s applications to growth and development and variation within biological organisms explores, using theoretical mathematics and the known behaviour of bio-chemicals under certain conditions for example, the reaction/diffusion of natural chemicals to explain the behaviour between and within cells during development. And on another scale, as organisms are a collection of trillions of highly specialised cells, it seems reasonable to suggest that Turing’s formula and equations can be applied in principle, to help explain and account for much of the great diversity of life in the natural world. This proposition finds much support which will become clear as the more detailed book on the topic reveals (Evolution: By Other Means).
For instance, if you follow Turing’s model and apply the line of reasoning and principles embedded in D’Arcy Thompson’s model, all the way from the chemical reaction scale, to the genetic molecule scale and beyond (DNA), to the cellular differential stage, to embryonic and all the way finally to the species scale, Nature does indeed appear to work according to self-similar patterns at every scale.
Indeed, Turing referred to the chemical interactions between cells as morphogens and proposed that cells patterned themselves according to the activation signal (diffusion) or, a deactivation signal (like a chemical off switch) causing a type of chain reaction (a certain sequence), which set up development patterns that once initiated, patterned itself repeatedly (reiteration/or committed to that developmental trajectory) accordingly.
In a sense, these chemical switches are one of the most fundamental processes for orchestrating, in a meaningful way, the differentiation of un-programmed cells into differentiated programmed and ultimately, highly specialised cells and on another scale, the undifferentiated organisms into differentiated species with their own specialism via their own evolved bio-chemical programs.
It is important therefore at this point to note that Turing’s theory of development of the organism from undifferentiated cells that is explicable via bio-chemical processes, does not directly involve the genetic code; it is indirect and explicitly via factors operating above and beyond the genes (epigenetics), where genes are only a small, but integral part of a much more adaptive whole system. This is because the genetic code itself cannot be the cause of the different specialisations of the cells (bone, tissue, neurons etc) as there is nothing in the identical code in every cell that would allow them to become anything different.
For example, we know that when development begins that the pluripotent (stem-cells) are essentially cellular clones (same DNA sequence), which should look and act exactly the same if they are all genetically identical, but of course we know that the cells in the body become (during development) a multitude of different things. They end up extremely different to one another once they differentiate into highly ordered and specialised cooperative colonies of bone, tissue, organ and neuron type cells within an organism. In other words, cells need to have their own special programs to run and allow them to become something other than copies/clones of each other.
Having one and the same genetic code doesn’t have the information necessary to allow these cells to express the genetic code differently and differentiate as yet. So how do these bio-chemical ‘on’ or ‘off’ switches proposed in Turing’s model get triggered and ultimately help these undifferentiated (stem-cells) to become differentiated, highly specialised ones, if it isn’t the genes directly?
To find out more, read the chapter on Turing and his theory by clicking the image at the top of this article. Essentially, as it turns out, the chemical basis of morphogenesis during development is also seemingly applicable at an evolutionary scale of life and begins to explain, quite eloquently, the morphogenesis of the species via epigenetic processes, which brings us to our next forgotten theory of evolution.
Karl Ernst Von Baer
EMBRYOLOGICAL DEVELOPMENT MIRRORS DEVELOPMENT OF THE SPECIES ON DIFFERENT SCALES
Von Baer Karl Ernst, Ritter von Baer -Prussian-Estonian embryologist (sometimes referred to as the Father of Embryology), proposed a theory regarding vertebrate development from egg to cellular differentiation to embryos and by re-winding its developmental stages, their evolutionary species developmental stages could be inferred as outlined by Elizabeth Barnes (2014) from the Arizona State University, Center for Biology and Society working on the Embryo Project Encyclopedia [Link] and her interpretation of Von Baer laws of embryology in both editions of his book Über Entwickelungsgeschichte der Thiere [On the Development of Animals], 1828 Link. The essence of Von Baer’s model formulated in a pre-genetic era is given below:
Von Baer proposed four main fundamental groups from which all modifications and divergence arose within the group as described below:
Karl Ernst von Baer’s Laws of Embryology
Von Baer’s first law states that the general characters of an animal group appear earlier in the embryo than the specialized characters do, which contradicted preformationist theories. Von Baer’s second law states that embryos develop from a uniform and noncomplex structure into an increasingly complicated and diverse organism. For example, a defining and general characteristic of vertebrates is the vertebral column […]. This feature appears early in the embryonic development of vertebrates.
However, other features that are more specific to groups within vertebrates, such as fur on mammals or scales on reptiles, form in a later developmental stage. Von Baer argued that this evidence supporting epigenetic development rather than development from preformed structures. He concluded from the first two laws that development occurs through epigenesis […], when the complex form of an animal arises gradually from unformed material during development.
Karl Ernst von Baer
The first law says that the general features of a large group of animals appear earlier in the embryo than the special features. The second law says that less general characters are developed from the most general, and so forth, until finally the most specialized appear. The third law is that instead of passing through the stages of other animals, each embryo of a given species departs more and more from them. Finally, the fourth law concludes from the previous three that the embryo of a higher animal is never like the adult of a lower animal, but only like its embryo.
Von Baer’s concept of principle (his laws) are reflected in recent research involving the study of brain development in vertebrates and its implication for our simplistic linear and continuous view of evolutionary development by A.B. Butler and others The quotes below are taken from ‘Evolution of Vertebrate Brains:
EVOLUTION OF VERTEBRATE BRAINS
….The simplistic … concept of evolution ranks organisms on an ascending scale that is presumed to reflect evolutionary history … While this concept is unfortunately widely and deeply embedded in the public consciousness, it is completely unsupported by the massive amount of data on evolution, not only for the brain but for all characters across the board.
…That brain enlargement and elaboration has occurred four times independently presents a very different reality of how brain evolution has operated than is perceived in the widely held folk-belief…
Butler (2009, 57)
… reptiles did not give rise to mammals any more than mammals gave rise to reptiles. In regard to embryological development, it likewise generally proceeds from the general (common ancestral features) to the specific (specializations of the taxon) … What is clearly established is that all taxa have their own specializations. Each taxon has a mix of primitive features.
Butler (2009, 64)
Basically, as you can see above, this brain study really begins to support a theory proposed over 180 years ago in a pre-molecular/genetic age and strongly supports the concept that species converge on ancestral features (shared ancestral condition) and then, later become specialists and they diverge from a shared (common) ancestral CONDITION, not a literal descent as the independent origins of brain types strongly suggests.
Karl Ernst von Baer
von Baer held that the animal kingdom could be separated into four distinct archetypes: the radiata (e.g., starfish and sea urchins), the mollusca (e.g., clams and octopus), the articulata (e.g., insects and crabs), and the vertebrata (e.g., fish and human beings). He denied recapitulation theory—the idea that the embryos of more complex animals passed through morphological stages comparable to those of the adult forms of organisms lower in the hierarchy of life. He maintained that the embryo of an animal exemplified from the beginning of its gestation only the archetype or Urform of that particular organism “The embryo of the vertebrate,” he asserted, “is already at the beginning a vertebrate” (1828-1837, 1: 220).
So a human fetus, he held, would move through stages in which it would take on the form of a generalized vertebrate, a generalized mammal, a generalized primate, and finally a particular human being. The form of the growing fetus moved from the general to the specific. The human embryo, in its early stages, therefore, never assumed the mature form of an invertebrate or of a fish.
Richards (nd. 2)
This begins to open up an alternative, less literal form of evolutionary development of the actual species. What made Von Baer’s model distinct from the Darwinian perspective was the means by which these commonly associated ancestral organisms had changed so dramatically through time. The Neo-Darwinian perspective sees it as a fishy-pod to walking amphibian/reptile to mammal progression as highlighted above in Butler’s study, whereas, Von Baer seen the complex patterning of embryological development as a scaled down version (not a literal recapitulation) of species formation itself (akin to D’Arcy Thompson’s view).
Von Baer extrapolated the patterns of development to infer that evolution had preceded from the unorganised cellular world, to the undefined generic (generalist) forms and from fundamental forms, diversified into a myriad of species (specialists) from these commonly shared templates, to put his theory in more modern language.
For instance, the following excerpt explains how many of Von Baer’s concepts are beginning to be supported by more recent studies as seen below:
Von Baer’s law for the ages: lost and found principles of developmental evolution
With advances in multiple fields, including paleontology, cladistics, phylogenetics, genomics, and cell and developmental biology, it is now possible to examine carefully the significance of von Baer’s law and its predictions…185 years after von Baer’s law was first formulated, its main concepts after proper refurbishing remain surprisingly relevant in revealing the fundamentals of the evolution–development connection, and suggest that their explanation should become the focus of renewed research.
Abzhanov (2013 Summary)
Von Baer’s laws are coming into clearer focus in the light of our more modern understanding of embryological development and how it may relate to species development. This is perhaps best illustrated via what has come to be described as the hourglass model, reflecting/ mirroring on another scale, species divergences away from their more generic and un-specialised primitive (embryonic-like) forms.
The developmental hourglass model is summarised in the excerpt below. (note embryogenesis means the origin of the embryo as a species and phylotypic means the phylo type where phylo refers to the shape and form of an organism):
The developmental hourglass model: a predictor of the basic body plan?
The hourglass model of embryonic evolution predicts an hourglass-like divergence during animal embryogenesis – with embryos being more divergent at the earliest and latest stages but conserved during a mid-embryonic (phylotypic) period that serves as a source of the basic body plan for animals within a phylum. Morphological observations have suggested hourglass-like divergence in various vertebrate and invertebrate groups, and recent molecular data support this model. However, further investigation is required to determine whether the phylotypic period represents a basic body plan for each animal phylum, and whether this principle might apply at higher taxonomic levels.
Naoki and Shigeru (2014, Abstract)
Fig. 3: Part of diagram sourced from: Naoki, I., and Shigeru, K., 2014, The developmental hourglass model: a predictor of the basic body plan? Development, Vol. 141, , Fig. 2, p. 4651 (adapted from Wang et. al. 2013) http://dev.biologists.org/content/develop/141/24/4649.full.pdf
Below is another excerpt relating to the hourglass model and directly links recent molecular investigations to the pattern predicted specifically in Von Baer’s third law that corresponds with the latter phase of the embryological developmental hourglass model.
In search of the vertebrate phylotypic stage: A molecular examination of the developmental hourglass model and von Baer’s third law
In 1828, Karl von Baer proposed a set of four evolutionary “laws” pertaining to embryological development. According to von Baer’s third law, young embryos from different species are relatively undifferentiated and resemble one another but as development proceeds, distinguishing features of the species begin to appear and embryos of different species progressively diverge from one another.
..According to the hourglass model, ontogeny is characterized by a starting point at which different taxa differ markedly from one another, followed by a stage of reduced intertaxonomic variability (the phylotypic stage), and ending in a von-Baer-like progressive divergence among the taxa. …The molecular evidence for the later parts of the hourglass model, i.e., for von Baer’s third law, was stronger than that for the earlier parts.
Hazkani-Covo, et al (2005 Abstract)
The hourglass model is idealised to show the type of convergence (on a shared ancestral condition, I would like to stress, rather than a literal ancestral common ancestral form) and this is where the following excerpt becomes interesting.
There is no highly conserved embryonic stage in the vertebrates: implications for current theories of evolution and development
Embryos of different species of vertebrate share a common organisation and often look similar. Adult differences among species become more apparent through divergence at later stages…Our survey seriously undermines the credibility of Haeckel’s drawings, which depict not a conserved stage for vertebrates, but a stylised amniote embryo. In fact, the taxonomic level of greatest resemblance among vertebrate embryos is below the subphylum.
Richardson et al (1997, Abstract)
This bottleneck of the hourglass does not therefore correspond to the ‘conserved stage’ employed by the literal and linear model of common genetic descent, but to a stylised amniotic embryo stage, which is important as this describes not only a more primitive and less defined stage in the amniotic organisms (these include all vertebrates that are not fish or amphibian types), but it implies a much earlier stage in evolutionary development akin to when Butler’s study established a fundamental ancestral shared generalist condition amongst the vertebrate groups .
This begins to correspond closely with Von Baer’s laws of going from the generic generalist forms (archetypes) and diverging into increasingly independent and more specialised forms that we might call an adult species. And of course reflects the study carried out by Butler on the evolution of vertebrate brains where the results suggest independent evolution of the brains within the broader vertebrate groups and descent from a commonly shared ancestral condition rather than the simplistic linear model of fish to amphibian, to reptile and mammal etc we currently employ today.
Von Baer’s developmental model for vertebrates can be easily scaled up to an evolutionary level of speciation and when restated in the light of our most up-to-date understanding of epigenetics, this becomes a very dynamic model indeed and has the potential to unlock the otherwise unknown course of the evolutionary past.
This now brings us to a name that is virtually synonymous with epigenetics: Jean Baptiste Lamarck, but again like Von Baer’s concepts of evolution, these were developed within a pre-genetic age, but is being confirmed and supported by our most up to date studies that have explored the nature of genetics and molecular biology in particular.
THE ORIGINAL NATURAL EVOLUTIONARY THEORY OF DESCENT – BY EPIGENETIC MODIFICATION
The evolutionary ideas of Jean-Baptiste Lamarck French Naturalist and early biologist and Original Founder of Modern Evolutionary Thought, [Link] (Packard. 1901) go back to over 200 years and are most commonly associated with his fully comprehensive publication Philosophie Zoologique (“Zoological Philosophy: Exposition with Regard to the Natural History of Animals”). This comprehensive theory was informed by his deep anatomical study of a vast array of species, as indicated below:
*Lamarck had acquainted himself with an astonishingly large number of animal and plant species, and it had not escaped him that the individual members, by changing their environment, under the influence of changed feeding requirements with regard to their body proportions, underwent many changes in their physical appearance and organization.
Gershenowitz (1983. 146)
*Quote above translated by Gershenowitz ‘Lamarck As Founder of the Theory of Descent’, written in German by Carl Claus, published by Alfred Holder, Vienna, 1888, p. 11.
*In German: “Lamack als Begrunder der Descendenziehre” [Link]
Interestingly, Lamarck’s main treatise on the topic of evolution came out the same year of Charles Darwin’s birth – 1809, but wasn’t translated into English until 1914 (See translation by Hugh Elliot [Link]) although, unfortunately, World War I. broke out, so it took quite a long time for Lamarck’s original ideas to filter out to the English-speaking world and even then, the English speaking world were finding that Neo-Darwinism was incrementally being installed within the academic institutions at the expense of Lamarckian type evolutionary thought. But, fortunately now, Lamarckian evolutionary principles are finally beginning to return from their long, arduous and scientifically unwarranted exile, which I will briefly outline further on in this article.
In order to gain a better insight into what some scientists thought of Lamarck’s theory back in the day, particularly prior to the installation of modern Darwinism, I believe Ernst Haeckel, writing at the end of the nineteenth century summarises Lamarck’s evolutionary theory quite succinctly below:
The Evolution of Man
To enable my readers to judge of the great value of the Philosophie Zoologique, I shall here briefly mention some of the most important of Lamarck’s ideas. According to him there is no essential difference between animate and inamimate nature; all nature is a single world of connected phenomena, and the same causes which form and transform inanimate natural bodies are alone those which are at work in animate nature. Hence, we must apply the same methods of investigation and explanation to both. Life is only a physical phenomenon. The conditions of internal and external form of all organisms-plants and animals, with man at their head-are to be explained, like those of minerals and other inanimate natural bodies, only by natural causes… The same is true of the origin of the various species…
Haeckel (1897, 83)
In many ways, as indicated above, Haeckel reflects in his view of Lamarck’s theory, a relatively untainted understanding as this was prior to the rise of the Neo-Darwinian synthesisers and their staunchly gene-centred evolutionary theory. For instance, epigenetics could not be more different to this gene/selectionist view, and yet epigenetics is virtually synonymous with the Lamarckian form of evolutionary species formation, and therefore, begins to account for the main cause of the unwarranted dismissal and ridicule of Lamarckian evolutionary concepts from the Neo-Darwinist camp, and, the main reason why it is important to highlight where Lamarck’s theory stands, scientifically.
In the deep reading of Lamarck’s work (see following link [Link] for most of his publications and related works in both English translation and original French), it becomes clear that what he meant by acquired characteristics is that species (particularly as they were themselves developing) could be modified in accordance with their ancestral/evolutionary environmental conditions/interactions and all of this was driven by natural laws that shape, form and mould and ultimately adapt each species – going from the generalist to the specialist – to be all that it can be according to its intrinsic or innate complexity.
In other words, Lamarck’s theory is underpinned by the fundamentals of epigenesis/epigenetic processes of non-preformation of the cells and embryo (as also advocated by Von Baer’s study and scaled-up to the species level) as it particularly extends out to the species scale of formation. Lamarck’s expertise, as indicated above, came from his deep anatomical research with extensive collections of specimens along with his insightful understanding of the nature of Nature. Essentially, Lamarck’s comprehensive evolutionary proposal could be described as modification via epigenetics. However, this term would not have been used by Lamarck, but instead, referred to this aspect of his formulation of the theory as: acquired characteristics.
Essentially, our current model of evolution excludes the inheritance of characters acquired via environmental interactions, and/or any impact of your experience/learning/nutrition within your own life-time; where, Lamarckian inheritance is just the opposite. The Neo-Darwinian doctrine advocates that everything is in the genes (pre-formationist – written in stone in the genes) and species survive because they carry the fittest genes that have been preserved (selected) or eliminated (also via selection by not being preserved). This is particularly interesting, considering that Charles Darwin himself was rather Lamarckian in his views and certainly not as dogmatic as his successors about selection being the only way (see books by Dig-Press on this site for more detail on Darwin’s own views).
As far back as 1907, in the publication entitled: Evolution and Animal Life… Lamarckian environmentally driven evolutionary concepts were clearly linked to epigenetics, (and the term is explicitly used) in the context of an emerging understanding of genetics and advances in embryology and that this Lamarckian-form of evolution which is highlighted as being widely supported around the turn of the late nineteenth and early 20th Century Jordan (1907, 56) [Link].
Historically there was a growing body of evidence to support the epigenetic/Lamarckian view of evolutionary change, particularly around the end of the 19th Century and earlier part of the 20th Century as seen below:
The Notions of Plasticity and Heredity among French Neo-Lamarckians (1880-1940): From Complementarity to Incompatibility
During the 1880s “Pasteur and his colleagues showed that some bacteria could be transformed by vary in culture conditions.” …”However, the most spectacular and clear results were obtained in botany…They performed numerous experiments in order to establish that the morphology, anatomy, and physiology of plants were dominated by abiotic parameters such as luminosity, temperature, and humidity.”Beginning in the 1880s (e.g. Bonnier) “Many characteristics of the plants were rapidly affected by the new environment: their size, color, general shape, for example, were changed. The results showed clearly that by changing growing conditions, it was possible to directly (i.e., without the need for natural selection) transform living plants.”
…”it was possible to transform one organ into another by imposing drastic changes in growing conditions. Indeed, by cultivating a stem under a mass of thick soil, one could observe transformations which slowly made the stem look like a root (Constantin 1883). He also obtained interesting results by pushing land plants into the water during their growth, which led to the disappearance of stomata (Constantin 1886). Whatever the trait, at every possible level and on every scale; it seemed that living organisms were capable of conforming to the requirements of their environment. All these results strengthened the idea of the transformability of life, and were widely discussed in France at the end of the nineteenth century.
Loison (2011, 68 – 69).
Lamarckian concepts continued to find empirical support as detailed in an excerpt from a science article by Yongsheng Liu, where we can see clearly that inherited traits (acquired characters) were demonstrated and even explored by Darwin himself.
Like father like son. A fresh review of the inheritance of acquired characteristics
There are also many records of graft-induced inheritable changes in plants and Darwin was the first to compile the available information on graft hybrid individuals produced from the cellular tissue of two different plants (Darwin 1868). Several famous plant breeders, including Luther Burbank (1849–1926) and Ivan Michurin (1855–1935), created plants with inheritable characteristics that were acquired from the tissues of both original plants.
In addition, about 500 papers on these types of hybridization experiment were published in the Soviet Union during the 1950s, although Western geneticists largely ignored the literature and dismissed the work as based on fraudulent results. Over the past decades, however, independent scientists have repeatedly shown that graft-induced variant characteristics in plants are stable and inheritable
…Oscar Hertwig in the late 19th century discovered a number of examples of phenotypic plasticity – the ability of an organism to alter its development, hence phenotype, depending on environmental conditions – such as that underlying the sexual dimorphism of the echiuroid worm Bonellia viridis.
But as discussed elsewhere (a common theme within this blog) epigenetics operating above and beyond the gene level along with their environmental-drivers (updated Lamarckian evolutionary principles) have been traditionally dismissed by the modern synthesis version of Darwinism, yet, there were never any scientific grounds for such a dismissal. As the historical record shows, it was much more to do with a Neo-Darwinian ideology; a story for another day perhaps? Moreover, epigenetics and its direct association with Lamarckian evolutionary concept of acquired characteristics is finally beginning to see resurgence again as indicated above as a result of our more modern era of molecular and genetic understanding as also seen below:
A Comeback for Lamarckian Evolution?
Lamarckian Evolution confirmed 200 years later in Epigenetic studies
Two new studies show that the effects of a mother’s early environment can be passed on to the next generation. The findings provide support for a 200-year-old theory of evolution that has been largely dismissed: Lamarckian evolution, which states that acquired characteristics can be passed on to offspring.
…In contrast to natural selection, in which organisms that are born well adapted to their environment survive and reproduce, passing down those successful traits, Lamarckian evolution suggests that animals can develop adaptive traits, such as better memory, during their lifetimes, and pass on those traits to their offspring. The latter theory was largely abandoned as Darwin’s, and later Mendel’s, theories took hold. But the concept of Lamarckian inheritance has made a comeback in recent years, as scientists learn more about epigenetics.
The following article entitled: What is a gene? What are genes? (2013) explains and it has a great deal to do with the epigenetics (Lamarckian style) and what has come to be known as the epigenome:
Initially, after the Human Genome Project was completed, we thought that much of the instructions for making the proteins that make an organism was contained in a tiny part of the genome, while the rest was simply “junk” DNA, without any useful function.
Later on, geneticists discovered another layer of heritable genetic data that are not held in the genome, but in the “epigenome”. In this area there are instructions on how to interpret the DNA code for the production of proteins. Some of the code for manufacturing the proteins of the epigenome was found to be hiding in junk DNA.
That discovery helped us understand that the c.23,000 genes in the human genome that can be found in all the cells of the human body are expressed differently in different organs and tissues. How they are expressed depends on gene regulation instructions located in the epigenome
This so-called junk DNA, which highlights the greatest differences between organisms and the coding DNA (for proteins that build and maintain everything) – your genes, is what all life-forms share and this is surprisingly similar across species. For example, we are not genetically that different to say a little wiggly worm. We actually share about two-thirds of our genes with a certain worm in particular. It is coding DNA (gene sequences) that we share, and it is epigenetics which makes the difference between how these otherwise, very similar genes are expressed that makes the real difference. This is the role of the epigenome and its dynamic adaptable system that intimately connects an organism at a cellular level to its environment; environmentally induced and acquired characteristics that can be inherited.
Below is another article that might help explain this epigenetic phenomenon a little better. Taken from the website about learning genetics (Utah education) under the heading: A Different Kind of Inheritance, it explains the following:
We’re used to thinking of inheritance in terms of the letters of the DNA code that pass to us from our parents […]The epigenetic code gives the genome a level of flexibility that extends beyond the relatively fixed DNA code. The epigenetic code allows certain types of information to be passed to offspring without having to go through the slow processes of random mutation and natural selection.
(from learn genetics via Utah education: A Different Kind of Inheritance)
This article continues to point out that recent studies are clearly demonstrating that modified behaviours can be inherited epigenetically.
A Different Kind of Inheritance…
“Some mother rats spend a lot of time licking, grooming and nursing their pups. Others seem to ignore their pups. Highly nurtured rat pups tend to grow up to be calm adults, while rat pups who receive little nurturing tend to grow up to be anxious.
It turns out that the difference between a calm and an anxious rat is not genetic – it’s epigenetic. The nurturing behavior of a mother rat during the first week of life shapes her pups’ epigenomes. And the epigenetic pattern that mom establishes tends to stay put, even after the pups become adults.
(from learn genetics via Utah education: A Different Kind of Inheritance)
These epigenetic studies of course have major implications for not only how we understand the evolutionary past, but also its implications for how we proceed, medically, socially and educationally in the future.
A comeback for Lamarckian evolution
….mice genetically engineered to have memory problems were raised in an enriched environment–given toys, exercise, and social interaction–for two weeks during adolescence. The animals’ memory improved–an unsurprising finding, given that enrichment has been previously shown to boost brain function. The mice were then returned to normal conditions, where they grew up and had offspring. This next generation of mice also had better memory, despite having the genetic defect and never having been exposed to the enriched environment.
MIT Technology Review: Emily Singer , Feb 4th 2009
All in all, the studied of epigenetics in our more modern era and the reinstatement of the Lamarckian form of evolutionary processes are seriously beginning to throw a bit of a spanner in the works of our more modern gene-centred and selection-driven form of evolutionary explanations as in the book review The Epigenetic Revolution by Nessa Carey as published in the Guardian.
“A book that would have had Darwin swooning”
So far, this is instructive and highly promising for medical research, but epigenetics finally reaches that “everything you’ve been told is wrong” moment when it claims that some epigenetic changes are so long-lasting they cover several generations: they can be inherited. This flouts one of biology’s most cherished dogmas – taught to all students – namely that changes acquired during life cannot be passed on – the heresy of Lamarckism. But the evidence that this can occur in some cases appears to be growing.
Forbes (2011 ‘Guardian’ 19th August)
This is particularly pertinent in the light of Richard Dawkins’ quote below taken from his famous book ‘The Selfish Gene‘, a view which he continues to staunchly adhere to even today.
The Selfish Gene:
Genes do indirectly control the manufacture of bodies, and the influence is strictly one way: acquired characteristics are not inherited. No matter how much knowledge and wisdom you acquire during your life, not one jot will be passed on to your children by genetic means. Each new generation starts from scratch.
— Dawkins (1989, 23) New Edition
But, Professor Noble would beg to differ on that as seen in his paper entitled: Physiology is rocking the foundations of evolutionary biology:
The “Modern Synthesis” (Neo-Darwinism) is a mid-twentieth century gene-centric view of evolution, based on random mutations accumulating to produce gradual change through natural selection. […] The organism became a mere carrier of the real objects of selection: its genes. We now know that genetic change is far from random and often not gradual. […] Acquired characteristics can be inherited…
Noble (2013, abstract)
But in direct response to Dawkins’ quote, for a little light relief, I would like to tell you a little story:
THE MOGGY CAT STORY
(A moggy cat is my term for one that isn’t bred from pure pedigree stock)
In the Darwinian model of evolution, the runt (the one that is weakly and sick and never gets much suckling from the mummy cat) of a litter would surely die and it would therefore not continue its lineage, perhaps because its mutant genes killed it? On the other hand, in my own personal experience, the runt of litters, if they do survive against the odds (which they typically do), they become much more resilient and strong because of their experience.
In other words, if you are looking for the fittest survival tactics, the moggy cat wins hands down and I’m afraid those better-bred pedigree cats just will not hack it in the dog eat dog world. They will not breed better and stronger cats and they will cost you a good deal more in the vets than your average moggy cat.
So I think you know the moral of this story. It is not the elimination of the gene-pool of the weaker species at the expense of best-bred with the good gene-pool that is selected in nature for survival, as these go on to out-compete, out-produce others genetically akin to themselves; the unlucky ones that did not survive the rat (cat) race, but rather, it is a case of all creatures and organisms have an in-built adaptive system that allows them to, not only survive: but seemingly thrive.
Therefore, nothing needs to be selected for: Nature has found many ingenious ways to adapt the species – one being: evolution via epigenetic modification and seemingly according to natural laws of growth and form and at every conceivable scale of life.
Epigenetic modification is implicated in the differential programs for limb and organ regeneration, and particular metamorphic programs of many insects, where the same insect with the same genes expresses them epigenetically at different stages to look like a caterpillar earlier on in its development and a flying insect during a later stage. Epigenetics (or Turing’s differential bio-chemical triggers and suppressors – ‘on’ or ‘off’ chemical switches orchestrating cellular differential programs according to their developmental context) appear to work at all scales of life and these differential programs are as applicable to the initial cellular formation/differentiation of cells with the same genetic code, as they are to another scale of life: the differential divergences of the species itself (as discussed above in relation to von Baer’s laws).
For instance, Morphogenesis via Epigenesis during cellular differentiation and embryo development is seemingly essentially the same as morphosis/evolution via Epigenetics during species differentiation on another scale, where this is a replay of evolutionary development of going from the generalist to the specialist as reflected during the developmental phases of present-day embryonic growth.
Epigenetic processes are implicated in orchestrating meaningful adaptations; how big or how small species are according to the natural resources available, – heat, light, food, space, and ultimately metabolic concerns (to scale and in perfect proportion and in equilibrium with the environment and the whole system as proposed in D’Arcy Thompson’s model outlined above). For instance, blindness in cave-fish that live in the dark, but have a more heightened sense of hearing, (evolution by loss or use).
Epigenetic type evolution also helps explain the means of some lizards losing their legs and becoming snakes. It accounts for temperature dependent sex determination in many amphibian/lizard species and even fish and provides the mechanism for why vertebrates of the fish variety could never have developed fishy fingers, while less matured vertebrates in the making could. Furthermore, epigenetic processes can re-trigger old ancestral programs (program switching) even in seemingly non-metamorphosising species. Hormones being stimulated via the presence of iodine in algae for instance, and suddenly, some vertebrate species can go into metamorphosis.
Think how dynamic it would be to take a relatively unformed species in the making, something akin to a present-day amphibian species which can seemingly (almost miraculously) transform from a tadpole/larval-type organism which is a water-dependent swimmer (it would drown in air); go from a limbless blob with a tail, to a full-air-breathing, limbed, land-dwelling walker (which would drown if it didn’t reach land as a miniature frog).
Now, obviously, there is more to the genetic story itself, even beyond epigenetics and how we get metamorphosising amphibians in the first place, because we have to understand where all the genetic novelty came from to begin with so that epigenetic processes could act upon to orchestrate such diverse variations. Furthermore, Nature would appear to have a wild-card up her sleeve in the form of jumping genes with their ability to rapidly remodel entire genomes under the guiding influence of epigenetic processes – seemingly, so that something useful and not too crazy and experimental emerges as a result. This aspect of this rather un-Darwinian model of evolutionary development is outlined in more detail along with several epigenetic studies that support the means of speciation via epigenetic modification in the forthcoming book on: Evolution: A Scientific Thought Experiment – Book One: By Other Means…?
Yes, well, returning to our discussion above regarding Mr. Dawkins’ views on genetics, perhaps he was not licked enough as a child (like our little epigenetically modified rats described above). But all is not lost as, maybe Mr. Dawkins could update his reading on Lamarckian epigenetics in the light of our modern understanding of molecular biology. There are many on the topic, but I would definitely recommend the following which contains a number of essays which are historically revealing and will give you a clear insight into why and how Lamarckian ideas became effectively written out of the history books and it wasn’t due to the silliness of his ideas even if they were somewhat ahead of their time and it has taken us until more recent times to even begin getting them. Below is one of the many endorsements of the book, which I believe summarises the value of the book most succinctly as follows:
Endorsement of the Book ‘Transformations of Lamarckism from Subtle Fluids to Molecular Biology’
Ever since Darwin and the neo-Darwinians came to dominate the interpretation of evolutionary theory and its history, Lamarck has been ignored, misrepresented and stereotyped. The same was about to happen in the year of Darwin’s bicentennial, but thanks to Snait Gissis and Eva Jablonka, Lamarck has finally received the serious attention his work deserves.
The editors have assembled a group of world-class scholars – historians, philosophers, and evolutionary developmental biologists – to produce a far more accurate, comprehensive, and exciting portrait of Lamarck as one of the most sophisticated, knowledgeable, and influential naturalists of his day. […]
Allen (2011) [Link]
Below are a couple of very helpful video links which should help explain the misconceptions surrounding Lamarckian type evolution and the profound implications for evolution when we apply Lamarckian/epigenetic or non-gene-centred thinking to evolution. Maybe Mr. Dawkins would enjoy watching these also.
‘Who was Lamarck? And what did he think?’ on Turner channel at YOU TUBE (a short and to the point myth-dispelling video presented by a scientist looking at what Lamarck actually proposed as opposed to what we think he actually proposed) (Turner 2012) [Link] and, ‘Epigenetics in Evolution’ (short video interview with Dr Eva Jablonka on epigenetics and Lamarck and implications for our current model of evolution) (EpiGenie 2011) [Link].
I know Mr. Dawkins will never read the next books, but I will recommend them to you as, apart from the fact that I have personally researched, written and publishing these, I do believe they will give you a very real insight into this whole topic of Lamarck, epigenetics and the historical context of what really happened. See for instance: Lamarck and the Sad Tale of the Blind Cave-Fish. where I have also dealt with the background relating to Lamarck and our modern synthesis and focus on the specific epigenetic effect of loss or gain of traits, features, even limbs and organs of species according to environmental triggers – a key concept within Lamarck’s evolutionary theory. And another epigenetic alternative to evolutionary processes and a historical perspective on Lamarck as seen in The Epigenetic Caterpillar: An Alternative to the Neo-Darwinian view of the Peppered Moth Phenomenon (O’Hare 2015a) [Link] (O’Hare 2014) [Link].
All in all, there is a great deal of evidence to support Lamarck’s overall they of evolution – via epigenetic adaptation according to environmental factors and conditions of existence as detailed in book One Evolution: By Other Means…?