An Internal Evolutionary Mechanism: Origin of the Lamarckian Calluses of the Ostrich Origin of the Pentadactyl Pattern in Terrestrial Vertebrates

Contents: 1) Introduction
                 2) Origin of the Lamarckian Calluses of the Ostrich
                 3) Origin of the Pentadactyl Pattern in Terrestrial Vertebrates
                 4) The Post-Notochord Model

1) Introduction [back to top]

The following gives two examples of how the proposed Internal Evolutionary Mechanism could account for co-ordinated evolutionary changes. The whole concept of the mechanism can be found here but the part necessary for understanding the examples has been included on this page as The Post-Notochord Model

2) Origin of the Lamarckian Calluses of the Ostrich [back to top]

 The term "Lamarckism" has become synonymous with "the inheritance of acquired characteristics" which proposes that changes in an organism due to its interaction with the environment may be passed on to succeeding generations.

   A classic example is the ostrich which is born with calluses on its breast, pubis and rump. These are the areas in contact with the ground when an ostrich sits and Lamarckists argue that generations of calluses formed by sitting have caused their formation to become incorporated into the genome. They reason that for the calluses to appear in the very areas they are "needed" is simply too co-incidental to be the result of random genetic changes. Darwinists, of course, have an intellectual argument based on "Natural Selection" that rebuts this.

   One aspect of the calluses has particular signifance for the proposed internal evolutionary mechanism: in addition to those already mentioned calluses also appear on the ankles of the ostrich which, because of the way the feet  are turned outwards when sitting, do not make contact with the ground. The ostrich is the only two-toed bird still living and has evolved from a form that originally had three toes. The suggestion has been made [1] that the three-toed ostrich did not turn its feet outwards when sitting which would have brought the ankles into contact with the ground and hence account for the calluses being there.

   If all the calluses were indeed present in the three-toed ostrich then, during the period that it evolved into the two-toed variety, why didn`t those on the ankles "degenerate"?. After all they no longer had any function to fulfil and many other organisms have the vestigial remains of structures that have subsequently "degenerated" once they were no longer needed (the eye of the mole and thigh-bone of the whale being but two examples).

   Anyone who has formed a callus on the outside of the little finger through writing (a recent experience), or anywhere else by a more arduous activity, will know that a callus has two obvious "benefits":

1) Damage to the surface tissue  no longer occurs
2) Pain ceases

   When a human being engages in an activity that has the potential to form a callus then initially nerve impulses from the distressed tissue travel along the nervous system and up through the AONE (affecting equilibrium) to the conscious level where they are experienced as pain. It is in ignoring the localised pain but continuing the overall activity causing it that brings the callus into being. Once this happens, and whether the originating behaviour is repeated or not, impulses no longer emanate from the area of the callus to affect the AONE and be consciously experienced as pain.

   The proposed internal evolutionary mechanism would account for the initial formation of all the ostrich`s calluses by suggesting they continued to sit even though "mildly" distressed by the areas in contact with the ground. With succeeding generations behaving in the same way (possibly even as they evolved into ostriches) co-ordinated formation of the calluses would have been incorporated into the genome once the threshold of the AONE was crossed to a degree recognising pain from the distressed areas was a permanent part of the physical constancy of the world. Equilibrium of the AONE  would have been restored and thereafter unaffected by the "inputs" from the calluses irrespective of whether the ostrich was standing or sitting.

   During evolution of the three-toed ostrich into the two-toed variety there continued to be no impulses from the ankle calluses to upset the AONE . Consequently they are still there.

[Cite as "Origin of the Lamarckian Calluses of the Ostrich: An Internal Evolutionary Mechanism"]

3) Origin of the Pentadactyl Pattern in Terrestrial Vertebrates [back to top]

 The basic pentadactyl pattern (the human hand for example) is one found throughout the fore-limbs of terrestrial vertebrates and evolutionists, including Darwin, have used this fact as a strong indicator of descent from a common (amphibian) ancestor. The pattern, however, also appears in the hind-limbs and it has been said that no evolutionist can claim that the front and rear limbs have evolved from a common source [2].

   The following is not concerned with the specific pattern itself (i.e. "Why 5 and not 6, 7 or 8?") but with the probability that there was indeed a "common source" that caused the pattern to appear in both sets of limbs.

   From today`s intellectual viewpoint conventional theory describes an eel, for example, as an organism perfectly adapted to its environment. In addition its form is said to be the accumulated result of beneficial random genetic mutations screened by Natural Selection. Two years ago a program on British television ("Screaming Reels") showed a man offering food to an eel that came halfway out of the water, onto the flat riverbank, in an attempt to reach it. Presumably it had taken the eel some time to recognise the man as a source of food but, in following the "HUNGER-SEE FOOD-EAT IT!" impulse, the eel had propelled itself into an environment for which it wasn`t "adapted" at all. The impulse to eat was so strong, in fact, that even when it couldn`t emerge any further the motion of the eel`s fins continued unabated.

   Submerged an eel is buoyant and experiences uniform resistance to movement over the entire surface area of its fins which, for a given effort, propel the eel a proportional distance. What would have been the temporary effect on the AONE of the eel as it made its brief foray into the alien environment?.

   As the eel began to emerge from the water gravity started to have an effect but the first major upset to the AONE would have been the immediate differential appearing across the forward fins. The tops, meeting "zero" resistance, were wildly describing great arcs through the air but no longer contributed to achieving forward momentum. To use an analogy this would be, at the level of the AONE, like a suddenly unnecessary telephone continuously "over-ringing" and thereby upsetting equilibrium. The base of the fins met increased resistance where they made contact with the mud and consequently moved over a much smaller distance relative to when submerged. At the AONE this would be like a necessary telephone suddenly continuously "under-ringing" which would further affect equilibrium. In addition the base of the forward fins, in conjunction with those still submerged, did achieve initial forward movement but it decreased in proportion to the amount of body exposed. Eventually the effect of gravity could no longer be overcome and at this point a final differential existed between the upper and lower halves of the exposed body, and that part still submerged.

   All this "information" is integrated by the AONE but maintaining continuity of Being entails maintaining integrity of Being: until the existing thresholds of the eel`s AONE were exceeded, or not met, then evolutionary changes would not occur.

   It is not too difficult to imagine, however, organisms similar to the eel living at a time when land vertebrates did not exist. Each time a proto-amphibian partially emerged from the water there would be consistency of experience of the new environment at the AONE. Persistency of such behaviour, perhaps coupled with increased necessity, could eventually cause the original thresholds of the AONE to be crossed initiating co-ordinated evolutionary changes to the genome available for the next generation: Tops of the fins: devolve until the "ringing" stops. Base of the fins: evolve into structures orientated towards - and reflecting the nature of - the "ground". Elongate the same to negate the effect of gravity on the body (the tops of the fins meeting little resistance in air being an indicator that equilibrium could be restored this way). The experience at the AONE of the fins supporting body weight could begin to be extrapolated upon and the proto-feet/undercarraige strengthened accordingly etc. etc..

   There would be no "direction" to these changes other than restoring the equilibrium of the AONE and neither would they be induced by the organism "wanting" them. The phrase "Changes in behaviour precede structural changes" is often encountered in articles on evolution but, in the example of the eel, it could be argued that there was no change in behaviour. Once the "HUNGER-SEE FOOD-EAT IT!" impulse was triggered the eel followed it blindly and would have had little "awareness" of being in an environment it wasn`t "adapted" for until the effects of being there reached the point that the original impulse was replaced by one of greater urgency: "MAINTAIN CONTINUITY OF BEING-RETURN TO WATER!".

   The starting point in the scenario involving proto-amphibians are organisms whose pectoral and pelvic fins were already being used in co-ordination. The evolutionary changes filtering down from the AONE would therefore apply to both sets of fins causing the pentadactyl pattern to appear in each. Initial differences between front and rear would continue to reflect "the head being at one end and the tail at the other". Further differentiation would then be determined by the subsequent experiences, at the AONE, of the organisms within the new environment. This can be illustrated, on a smaller scale, by the various species of finches found on the Galapagos Islands all of who evolved from a single common ancestor finch species. Amphibians need only to have evolved once, under any scenario, to have given rise to all the terrestrial vertebrates that are their evolutionary descendents each with their own version of the pentadactyl pattern.

[Cite as "Origin of the Pentadactyl Pattern in Terrestrial Vertebrates: An Internal Evolutionary Mechanism"]

References: [back to top]

[1] "The Great Evolution Mystery", Gordon Rattray Taylor, Secker & Warburg London, page 37. [back to text]

[2] "Evolution - A Theory in Crisis", Michael Denton, Burnett Books, London 1985, page 151. [back to text]

4) The Post-Notochord Model [references have been omitted from this extract] [back to top]

   

The diagram opposite shows a dotted area within which all internal and external "inputs" come together and it is here that an internal evolutionary mechanism is proposed to exist. Cannon (1929) formulated the concept of "homeostasis" whereby activity at this level can be described as "self regulating" or "automatic" which are observations of a closed system made from an external standpoint. The model proposes, when viewed from the inside, any non thinking and non intelligent organism with such a configuration is simply maintaining equilibrium and that this equilibrium extends in another direction - that of evolution.      The dotted area, arbitrarily labeled the A.O.N.E. ("Area of Natural Equilibrium"), is a localized area at the apex (or center) of the internal homeostatic hierarchy [Note 1: The Triune Brain]. The genome in such an organism's germ cells, equally hierarchically integrated, will also have a localized area and this connectivity reflects the continuity of organism - genome - organism.

     Changes in the life experiences of an organism experienced at the level of the AONE - not that of consciousness - may cause single or co-ordinated evolutionary/devolutionary changes to occur if existing thresholds are exceeded or, just as importantly, not met. These changes would be in a direction that restored equilibrium of the AONE.

    Signalling pathways from outputs of the AONE into the genomes of specific physically remote cells are known to exist as is a molecular mechanism, recently discovered in mammals, of a type that would also be necessary: "Experiments performed at the University of Maryland Medical Center have revealed a molecular mechanism that may be a significant driver of evolution in humans and other mammals. Certain retrotransposons - bits of DNA able to copy themselves from one region of the genome to another - are able to pick up flanking genetic sequences and then insert themselves and the tag-along DNA at new locations". Connect signalling pathways with such molecular mechanisms and the proposed action of the AONE on the genome is entirely possible.

   This brings to the fore, however, Weismann`s accepted theory that information gained by somatic cells cannot be transmitted to the germ cells that give rise to succeeding generations (the "Weismann Barrier). The proposed mechanism doesn`t contradict this because no direct connection between somatic and germ cells is suggested and illustrating this point is how the effect named after Weismann`s contemporary, J. Mark Baldwin, could be accounted for:

   In 1896 the paper "A New Factor in Evolution" was published by American Naturalist in which Baldwin, referring to his earlier publications, argued the case for a new factor that he called "Organic Selection". The "Baldwin Effect", as it is now more commonly known, says that the phenotypic plasticity of an organism (the ability to adapt to it`s environment) enables it to learn and that over succeeding generations a learned behaviour may eventually become instinctive (i.e. hereditary). Consider the following hypothetical example:

   As a human being learns the complex movements of riding a bicycle the inner co-ordination required is transferred into the cerebellum, a structure within the AONE, so that the activity then appears to be "automatic" and requires less conscious effort. In the cerebellum the desire to ride a bicycle obviously has no relevance and instead it is the overall ability of the non-intelligent organism to balance that becomes significant. If succeeding generations of human beings not only learned to ride bicycles but began doing so for greatly increased periods then any transient disruptions the activity produced in the AONE would be integrated during this time.

   Once existing thresholds were exceeded (see the experiment involving rats in the Method of Testing for a gross example of this happening) co-ordinated evolutionary changes would be triggered in a direction that would restore equilibrium. From an external viewpoint this would be perceived as a relative improvement in the ability of human beings to balance that would be independent of any specific activity.

   In addition once the hypothetical evolutionary changes were triggered they would continue to completion (i.e. restoration of equilibrium) even if the causing factor of riding bicycles were discontinued during the number of generations that such changes would require. One final point: the phenotypic plasticity of human beings is such that if the above example ever were to happen then there wouldn`t be an instinctive urge to ride bicycles but rather an instinctive recognition that it could be done, even if a human being on a bicycle had never been seen before.

   Homeostasis is the maintaining of equilibrium varying about a mean. If the above example is seen as a "positive" upset to equilibrium that would result in a relative improvement in the ability to balance then equally important are "negative" upsets the principle of which can be seen in this example:

   Although there are obvious difficulties in talking about single structures within a naturally integrated organism there existed earlier in Man's evolutionary history an ancestor whose tail provided a naturally utilized input into the AONE of that time. As the transition from ancestor to Man began (irrespective of elapsed time and externally identifiable intermediary stages) the tail began to be used less and less and once the degree of usage no longer reached the lower threshold of the AONE then devolution commenced.

   The reason this occurred is because equilibrium of the AONE would have been upset in a negative direction. Not meeting the lower threshold would be like waiting for a telephone to ring that no longer does (hardly scientific but neither is natural life and it does convey the concept rather well) and so the tail would have been partially devolved but only to a point that restored equilibrium of the AONE.

   This in turn set a new and lower threshold which, when it too was no longer reached, then caused the process to be repeated etc. until today a tail only exists for a short period of time during the growth of the human fetus. This reflects it's "position" within our current AONE. The transitory appearance of gills in the human fetus or even the appendix could serve equally well as examples.

   Other examples of phenotypic plasticity include the abilities to tan and  form calluses. The Lamarckian Calluses of the Ostrich looks at an example where calluses have become hereditary and emphasises how the proposed mechanism could explain why the callus on the ankle of the ostrich, the one that is no longer "necessary", is still there. The AONE is ideally placed to have differentiated between those large areas of skin requiring a hereditary degree of pigmentation and the smaller ones requiring calluses or the need to be relatively thicker (e.g. the soles of feet).

   Taking all the examples into account, and putting it in more general terms, the proposed mechanism has the potential, when looking at evolutionary history, to "put the right variations in the right place at the right point in time".

[Note 1:] Maclean's Triune Brain theory [Link 1] [Link 2] considers the human brain to consist of three parts ('reptilian', 'old mammalian', and 'new mammalian') which:

"appear, one after the other, during the development of the embryo and the fetus (ontogenesis), recapitulating, chronologically, the evolution of animal species (phylogenesis), from the lizards up to the homo sapiens."

A person in a coma demonstrates that the intellect is not required for biological survival and so an 'egocentric' view of the human organism may not be appropriate.

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