Evolution - Essay Question

Explain the operational mechanism behind evolution, if you believe it exists; otherwise label your model and explain why it doesn't.

respondent: Swinton Roof

In this paper I hope to dismiss the side arguments of creationism vs. evolution and naturalistic vs divine issues. Much philosophical time and confusion is wasted on these issues. The worst part is that they truly ignore the really central questions about what life is all about on this planet. I also think some of us have been guilty of accusing others of engaging in such philosophical boondoggling.

Webster's New World Dictionary defines evolution simply as an unfolding, process of development, or movement that is part of a series. It goes on to say that the theory of evolution is the theory that all species developed from earlier forms. I think only the 'creationists' would dispute this basic premis. On the otherhand, most scientists, while they believe the premis to be true in general, still continue to debate what the operational mechanism(s) might be for producing such a connected development of life forms.

I stated the theory is a premis, because all the evidence is really circumstantial. There are three main sources of empirical evidence for studying this question - the fossil record, genetic (DNA) studies, and the historical experience of breeding and husbandry. The experience of plant and animal breeders is that living forms are easily modified by generations of selection or culling and re- breeding of offspring. This observation gives strength to the idea that all species might have originated from earlier forms. There is a problem, however, in that all attempts to create new species thusly have failed. Hybrids and varieties are easily produced, but the offspring remain rooted as species to their progenitors. Also their experience has shown that viable diversity is achieved in a population by breeding in stock from outside the population.

Now consider the fossil record. The fossil record is at best, just an imprint or partial record in stone of a portion of the form a once living creature. Most of the soft inner details of living things do not survive fossilization. Also, the process has to have special conditions for development so the record must necessarily be a sketchy or incomplete one. The overall impression one gets from studying fossils is that there have been many species in the past which no longer exist. One can also get an impression that in a very broad sense, the overall complexity of living forms has increased over the ages. There are exceptions to this rule, but in general, there were early ages where simpler forms dominated and some classes were absent.

The fossil records have been the prime evidence for evolution. The major drawback, however, is that they offer no clues about possible mechanisms of evolution. They only strongly suggest that some sort of process has influenced the arrival and departure of new species on this planet. The fossil record really cannot even suggest with certainty that there is some inevitable progress toward a more advanced state.

Hypothetical aliens studying human fossils and those of dolphins might conjecture that they had some increased capacity over say dinosaurs, but if they were not familiar with vertebrate type brain cases they might not even know what that function was. They would be hard put to infer evolutionary position from fossil bones alone I think, except in a purely historical sense relative to the entire record. There is still some controversy about which species belong in which branch of fossil classification. There are a great number of fossil specimens which share similar traits from separate branches of the classification tree, yet which seem to have no distinct progenitor. There are many gaps and inconsistencies which do not seem to support any ideas of gradual development of forms.

Next we have the DNA evidence. Sadly, we have DNA only from recently alive creatures and a very small handfull of preserved specimens from the most recent epochs. DNA is the strongest evidence in a way because it has been shown to be the exact blueprint for the growth and development of every single individual lifeform ever encountered. Furthermore it has been shown that all forms share the exact same coding scheme using 4 nucleaic bases. This is a very strong argument for a common origin of all life on earth.

As true with all theories, however, they can never be completely proven, only disproven or supplanted by more inclusive theories. Statistical comparisons of gene code segments from species close and further apart on the classification tree have recently given almost ironclad evidence to support the idea of common origins, and scientists working in this field probably have reams of corrobative correlations that support this conviction. As above, however, the problem again is that the operational mechanism(s) remains elusive. It is my belief that the answers will ultimately come from DNA research. Let us step back then and see how we might approach this question. Till now I have only given a bit of background and highlighted what the question is.

Operational mechanism - what could it be. For a long time, many scientists have been content to accept the traditional Darwinian view. This view is that variations in species occur naturally. Natural selection, acting over time, removes less fit variations, and the species as a whole gradually diverges from its original state. Given enough time and ( most importantly ) geographical isolation, one ends up with new species. This is 'gradualism' in its most basic form. I believe 'natural selection' is indisputable, except I do object to the word natural. The problem is that semantically speaking, this word invites the natural vs. divine debate.

Survival of the fittest likewise causes problems because, fitness is relative to circumstance and change and not necessarily an ongoing improvement. The theory is thus suggestive and glosses over the actual mechanisms. There are two basic flaws to Darwinian evolution as I see it. First and most damning is the idea of gradualism. The above mentioned empirical data simply do not support it. Punctuated equilibria of species is the new catchword for what the evidence suggests. The second flaw is that only one half of an operational mechanism is given by the theory. A species must actually be there living in order for natural selection to operate. To avoid infinite regress one must postulate an initial mother life form for evolution to proceed from. This opens the door for the creationist debate again. Aaaaghh! Just how do these so-called natural variations occur.

Well, scientists were very happy when they discovered genetics and random mutations. Everything seemed neat and tidy except for the gradualism problem. Experimentalists working with radiation induced random mutations on critters with very short temporal life-cycles, were over 30 years or so not able to produce a single new species. Incredibly, a species seemed to have some power to forcibly maintain its integrity over time. Animal and plant breeders concur on this fact also. Genetics has to be where the changes take place but apparently uncoordinated single point mutations wont get you there. Massive duplication of chromosomes ( diploidization ) will produce new species, but as a general mechanism for evolution is untenable because of the exponential catastrophe problem and is not supported by DNA evidence either. It is thus relegated to being an occasional factor in evolution, not a major operative mechanism.

Other mechanisms are said to be extant but I do not know what they are. One could propose a 'pot pourri' of paths to species creation but I would caution one to consider first that a species is an incredibly complex coordinated affair. Any tampering or reordering of genetic material on the smallest scales can lead to non-viable organisms, much less a robust new species. My own view is that any such mechanism must be INTIMATELY involved with the organizing principles of DNA itself. My own experience with programming computers echoes a similar problem. Any random single change to a program can lead to disaster. Any changes which don't are invariably trivial and uninteresting.

To create a new viable program, one literally has to reason out a whole series of relations and interactions and reconcile them. This has to be done from a higher or more abstract viewpoint. Please don't misunderstand my metaphor and think that I am proposing divine mechanism. I am merely pointing out that evolution cannot occur in a peacemeal fashion - either gradually or not. It is our viewpoint or model which needs some divine inspiration. DNA as the prime code for an organism MUST have some sort of internal consistency which leads to a healthy functioning organism. It has been found that DNA even endeavors to repair itself and maintain its consistency at all costs by means of redundancy, sequential specificity, and XXX shhhh! XXX.

At this point in time no one has all the answers. Recent simulations inspired by chaos theory and complexity theory have revealed some rather startling correlations with the way populations seem to evolve over time. If valid they suggest that the complexity and internal consistency of DNA itself give it the power to actually reorganize itself in a consistent and viable way. If so, then evolution is truly an 'unfolding' natural process whose mystery lies only in the unpredictable nature of its results. Most everyone is aware of the fact that DNA encodes the structure and function of life forms, but how many are aware of the vast implications of this fact? Pondering this question alone, can open one to a new round of philosohical debate, where all the old questions can reimerge in a new guise. Perhaps the debate itself evolves as part of THE process. This paper actually only touched the questions. I hope the reader agrees that I have only pointed a finger at where answers might lie.

Swinton