Sunday, August 3, 2014

HOMOLOGY

"It must be stressed that Darwin himself never claimed to provide proof of evolution or of the origin of species, what he did claim was that if evolution has occurred, a number of otherwise inexplicable facts are readily explained. The evidence for evolution was therefore indirect….The indirect evidence for evolution is based primarily on the significance of similarities found in different organisms…The similarity of plan is easily explicable if all descended with modification from a common ancestor,  by evolution, and the term homologous is used to denote corresponding structures formed this way….In vertebrate animals, the skeleton of the forelimb is a splendid example of homology, in the bones of the upper arm, forearm, wrist, hand, and fingers, all of which can be matched, bone for bone, in rat, dog, horse, bat, mole, porpoise, or man.  The example is all the more telling because the bones have become modified in adaptation to different modes of life but have retained the same fundamental plan of structure, inherited from a common ancestor."    The Encyclopedia Brittanica

The similarity of this most famous example of homology, of the forelimb, consists of one large bone leading from the torso of the body, separating into two bones and then into five.  In humans that would be the humerus bone leading from the shoulder to the elbow, the ulna and radius bones leading from the elbow to the wrist and then starting at the wrist, five bones, the carpals, joined by skin within the hand, leading to five metacarpals, or fingers, emerging from the outer edge of the hand.  It is this pattern, one, two, five, repeated in the forelimbs through all classes of vertebrates, fish, amphibians, reptiles, birds and mammals, in fins, wings and arms, which must be isolated as the homologous factor.  There is no homology of genes.  These different organs are specified by different genes, and, although the bones of these wings, fins and arms are made of similar materials which may be specified by some overlapping genes, many of the genes composing these features are quite different.  Also, going back to the embryology of each of these, we find no similarity, whatsoever, between the embryology which leads to the differentiation and the pattern of migration of cells which lead to the fin of the fish, the wing of the bird, and the forearm or foreleg of the mammal.  The way that the original oocyte replicates in each of the classes of vertebrates to form a blastocyst and then the way that the cells of the blastocyst twist, turn and migrate to form the gastrula, is so different in each of the classes, that the only conclusion is that completely different patterns of cell specialization, and cell migration, lead to the formation of so-called homologous features.  This is not only true for the forearm, but for every feature shared between classes that are referred to as homologous.


So what is it that is shared, if it is not the genes, nor the method of construction of these features.  It is the shape, the pattern, the plan.  In the case of the forearm it is the one-two-five plan. In the case of the kidneys, it is the shape of the kidneys.  For the eye, it is the basic shape of the eye, with the lens within it.  Now have these plans and shapes been randomly come upon by accidental mutations, by random copying errors of genes?  Of course not. Mutations in genes may change the shape of the protein molecule which they specify, but aside from the sub-microscopic shape of the protein molecule, genes by themselves couldn't possibly have anything to do with the causing of shapes.  In fact in our bodies probably all our genes and certainly the great, great majority of our genes are pleiotropic.  That is, they are used in a variety of different situations in the body and are involved in the formation of a wide variety of shapes.  To say that genes, by themselves,  determine shapes would be like saying that grains of sand determine the shape of sand sculptures, or that the tiniest pixels of modern optical technology (still exponentially larger than protein molecules), determine, or even limit the shapes of the pictures that are formed by these pixels.


If accidentally some ancient organism stumbled upon a shape that gave that organism a survival advantage, where was the knowledge of that shape stored?  How was that shape communicated to successive generations?  Certainly not through the inheritance of mutated genes.  Any new shape must be accompanied by a change in blood circulation to supply nutrients to that new shape; new changes in the nervous system to supply sensation or control or both to the area of that new shape; changes in the real estate of the brain to connect nerves from that new shape to specific areas of the brain that would allow the organism to experience heat or touch or optical or aural or taste sensations from the material of that new shape.  There may be a change in the entire structure of the body to maintain equilibrium after the introduction of that new shape.  There would have to be an entire restructuring of the unfathomably complicated genetic firing patterns during embryology and a shift in the patterns of cell differentiation and migration of cells during gastrulation to recreate this new shape.  Some of these changes involve genes, to the extent that new materials or different amounts of old materials are needed to form all the nerve and muscle and blood vessel, and bone and skin materials involved in this new shape, but it is absurd to think of the genes, the passive genes, whose sole activity is to allow themselves to be copied, and that at the behest of protein molecules; to think of the genes as the causative origin of these new shapes.


So what does cause a new shape?  Let's look no further than the world of human technology.  Here we find a wheel made out of rubber, and a wheel made out of plastic.  Other wheels are constructed from wood and metal.  Each method of construction is different.  The size and materials of the wheels are different.  The wheel has been adapted to thousands of different uses.  The same thing can be said for the metal screw and the wood screw and the plastic screw, and the flathead screw and the Phillips head screw.  Yes, they share an ancestor, but the ancestor is not the original wheel or the original screw but the original idea for the orignal wheel and the original screw.


Many inventions of human technology can be identified by a specific inventor.  But that inventor was the inheritor of many, many ideas that had already been discovered in the inventor's society or recorded from other societies, and it was by using the knowledge of all these previous ideas, that the inventor came upon her new idea, which built on (or evolved from) all the ideas that preceded it.  Exactly the same in biology.  One-two-five is a construction idea.  That is how homologous organisms are related. They are the products of the same ideas:  the idea of a genetic code, the idea of fitting nucleotides to amino acids; the idea of oxygen based metabolism, the idea of one two five one, etc. 


And, of course, genes are involved.  The entire genetic system, not just the genes, but the enormously complex timing pattern of when genes are fired and the delivery system of the genetic information to the cytoplasm of the cell, and the translation of the genetic information into an amino acid chain, and the folding process of the chain and the addition of other chemicals to that chain and the delivery of the finished protein to the exact part of the body where it is needed, are all part of the transcendantally brilliant way of providing all the precise biological building materials in the exact shape and exact chemical quality, and in the exact quantity and at the exact moment and to the exact place that they are needed, so that they can be constructed and shaped in the precise way that realizes all the ideas of their creator.  In sexual reproduction and when we breed plants and animals or genetically engineer them, we are  mixing not just individual genes, but whole complexes of genes and their timing systems; but what we are really mixing are the ideas that these genetic systems have been created to materialize. 


We are living beings that inhabit living organisms.  As living beings we are not merely related;  we are actually aspects of the same one being, inhabiting different organisms.  The organisms that we inhabit are related in that they are all products of ideas from the same mind, the same being, the same cosmic consciousness, the same God.


Just consider for a moment the hind limbs.  The hind limbs, just like the dorsal fins, also display the exact same one two five pattern.  In humans we have a femur leading from the hip to the knee; a tibia and fibula bone leading from the knee to the ankle; five separate tarsals covered by skin in the foot, emerging as separate metatarsals or toes from the foot.  No one suggests that the hind limbs were inherited from the fore limbs.  If they evolved in a neo-Darwinist fashion, they must have evolved separately.  So how did their basic pattern of bones wind up being identical?  Was this a random, tiny advantageous mutation by tiny advantageous mutation process that was taking place simultaneously in the fore and hind limbs and both processes just happened to randomly stumble upon the exact same sequence of fortuitous mutations that resulted in two identical patterns?


It is absurd.  Homologousnes as caused by common random inheritance is absurd.  That an organism, a biological, material organism,  could retain somehow the understanding of a shape and communicate that through genes to its progeny is absurd.  Exactly as in human technology, our biological machines are the culmination of all the ideas that led up to them, ideas that were motivated by the desire to provide for the inhabitors of these organisms the most interesting, most varied, most satisfying life experience possible given the environmental conditions on this planet at different points in our geological and atmospheric and ecological history.  Evolution is the result, not of a random accumulation of materials, but of a purposeful accumulation of ideas.


Please comment.  I know that many people are reading these blog posts.  Please let me hear from you.  Thanks.



1 comment:

Bill Schwan said...

Hi and thanks again for thinking things through to their logical conclusions. I really appreciate the way you bring troublesome side processes that are vital to the continued usefulness of a mutation but which require a wholesale reordering of a majority of the organism to accommodate the mutation. The whole shebang must adjust to allow the oddball mutation to coexist with the established system. So much more must take place than just a happenstance mutation. Thank you for your efforts.