Tuesday, March 08, 2005

Evolution - Here I Stand! I Can Do Nuttin' Else.

I got an interesting comment about my last post so I thought I would answer it in the form of a post. I hope this does not breach some kind of blogging etiquette.

Robert said...

I would like to turn your arguments in the comment thread of your last post back to you.

"For those of us that not only accept evolution but are interested in it..." My question is simply: why have you seemingly put your skepticism aside for the purpose of "accepting" evolution? Before I'm accused of being a "creationist", note that I have heretofore made no such claim. It just strikes me as inconsistent for you to assent to a theory that has yet to be conclusively proven. Granted, the preponderance of evidence may strongly suggest it's validity. I postulate that one relies more heavily upon conjecture to bridge the gaps in the fossil record than one for whom the Bible is supporting evidence for the existence God. ;)



Good question. It all boils down to what I have personally learned and the fact that our standards for whether or not a theory has "yet to be conclusively proven" are different.

I have been interested in many fields of science to varying degrees since childhood . I am even currently working on a more formal education in Biology at University after being in the civil service for a spell. However I should go back a bit in my education to explain how I accepted evolution.

There came a point in high school where I had been reading about Darwin on my own (school I was at had a Catholic nun on the board so the science teacher did not dwell long on the topic) when it suddenly clicked as to how things like survivability and viability of an organism would affect how often it would be able to pass on its genes and thus how widely those genes would be expressed. If new genes were emerging at a slow but constant rate (I would only learn how later in my education), there could be no other outcome than for those genes to be either screened out by killing the organism or preventing mating, or spread into the greater population where they would either increase or decrease in frequency based on the probability of survival for all individuals that had them. Over time, all non lethal genes would be tested and either pushed out or achieve some fraction of penetration in the population. For really useful genes, that fraction would be 100%. What else was possible? Could genes and combinations of genes that made an animal more adapted to its environment, more likely to survive and reproduce become less prevalent over time? Would traits that left one unable to find mates or food gradually take over a population. The logic seemed pretty unassailable.

As I went through some university (followed by a temporary escape from academia) and also pursued my education on a personal level, I was aware that the theory was not accepted by a large fraction of people, almost all of whom were outside the scientific community like philosophers, theologians, normal every-day people and graduates from Bible colleges. Those few who were scientists tended to be physicists, mathematicians... people with little or no background in biology. While this itself does not discredit their arguments it is worth considering their lack of education in the field they are criticizing. I read the arguments by creationists of various types and backgrounds - young earth, old earth, left-wing relativists, right-wing fundamentalists, Christians, Hindus, Intelligent Design theorists and all of their points were easily and repeatedly addressed by evolutionists. This did not dispel the points though; they kept repeating the same tired criticisms year after year like appealing to thermodynamics (as if earth were a closed system). Only occasionally coming up with something new but equally fallacious.

I can't remember exactly when it happened that I went from feeling that evolution was the most likely theory to account for the natural world to being certain that it was the only theory that was consistent with everything I had learned and discovered. I gradually became struck by the fact that all of these different fields I had been interested in (due to their fundamental significance to questions like: Who are we? What is life? What is reality? etc.) were all pointing in the same direction. Observations from fields including biology (from molecular and population genetic to embryology to cellular, right up to the ecosystem level), anthropology (paleoanthropology, primatology,) cosmology, computer science, geology (to the limited extent that I was interested) were all delivering information that fit in perfectly with the evolutionary model and yet were virtually impossible to account for in the absence of that model. Is it likely that God or some other power would have created a universe that was perfectly and completely designed to look like an evolutionary one and which had laws of physics and principals of biology that would allow - no insist - that evolution happen, and yet this same entity would somehow prevent evolution from occurring?

As far as the "gaps in the fossil record" and the "lack of intermediate fossils" as opponents of evolution often claim exist... quite frankly, it is not entirely true. It is true that there has never been a discovery of millions of individual fossils from successive species, lined up like a Soviet bread queue so we can see a skeleton from every thousand years and play them back like a flip book. That being said, the museums and universities of the world are filled with drawers and drawers full of fossils that show individuals of species that share more traits with those organisms that are found in similarly dated rock and fewer with those that are further removed in geological time. Many intermediate species have been found.

In the ape to human branch of the fossil record we should expect there to be few fossils due to the short geological time frame involved and yet we do have a significant number of intermediate fossils. Take a look at this site. Notice how the top row of modern ape skulls is so distinct from the lower row of humans. Then look at the middle rows. What possible reason could there be for finding old skulls that share traits of both apes and humans even though neither modern apes nor humans are seen today with skulls of this shape and yet find no modern looking human skulls before about 180,000 years ago? Given the amount of evidence for evolution of other species like mammals, amphibians etc. and the transitional forms in the fossil record (not to mention egg laying mammals like the platypus), does it really take much faith or "conjecture" to conclude that these skulls belonged to various intermediate proto-humans?

I have not gone in to the topic of vestigial organs and tissues or the genetic evidence for evolution like how neutral mutations accumulate in a manner that can be used to compare species' genetic similarity and how these changes correlate with the fossil record to a such a degree that would not be expected without evolution because I am getting tired now. Perhaps in another post.

Skepticism is not an absolute law but a set of principals. Believing something in the absence of sufficient evidence goes against these principles. Believing something despite sufficient evidence to the contrary is also. How much evidence is sufficient though is a judgment call.

When all of the information and observations that I have been able to obtain (a considerable amount, I feel), not only support a theory but are in many cases are incomprehensible without the theory; when all arguments and opposing claims I have seen are inconsistent with reason and available evidence; when there are no competing claims, I am willing to conclude that the theory has been proven conclusively. For any theory to displace it or for any argument to challenge it in my mind, I would have to see how it could account for all or at least much of what evolution does. For instance if an elf were to appear, prove to me that he could make universes and explain to me why and how he had created a universe designed to trick us, I would certainly reevaluate the modern evolutionary model. I would not however feel foolish since he seems to have put on one hell of a show.

That does not mean that the evolutionary theory is finished. There will no doubt be things we learn about evolution as we continue to study life both past and present. In fact, only a few months ago I was reading about the work of a mathematician with computer simulations that showed how a species can be divided into two separate breeding populations by a single selective pressure long before any mutations occur. Before this many biologists assumed that a population would need to be separated by geography and accumulate mutations before they would be unable (or unwilling) to interbreed. Not only did the simulations support his point but it made perfect logical sense as well. I have been meaning to do a post about it as soon as I can track down the article.

In closing here are a couple of extra links on the issue. The first one is my favorite because it represents an entirely new form of evolution to study.

http://www.carlzimmer.com/articles/2005/articles_2005_Avida.html

http://www.talkorigins.org/faqs/comdesc/

http://www.talkorigins.org/faqs/comdesc/section2.html#ontogeny_ex3

P.S. I will be away for a few days so I may or may not post this week. I am trusting the Internet to be on its best behavior in my absence so no monkey business!

5 Comments:

At Tue Mar 08, 06:34:00 PM 2005, Anonymous Robert said...

I appreciate your thoughtful response. Your arguments strike me as being consistent with that which I have previously heard from other proponents of modern evolutionary theory (I’m no expert). This is not unlike theoretical/quantum physicists, in that they too have much information, but no ultimate *unified theory*. Even the most avid supporters of so called *string theory* stop short of calling it fact. What I’m getting at is this: microevolution seems to be a priori, but conclusive evidence (strictly defined) for macro is conspicuously absent. Is there circumstantial evidence for macro...sure. The same could be said for string theory. The fact that all carbon based life forms share common traits is not surprising. I think the logical leap occurs when one insists upon common ancestry. Your link notwithstanding, the possibility that distinct species are and have always been distinct is, in my view, discounted without warrant. You seem to accept it’s veracity on the basis insufficient disproof, rather than immutable positive proof.

The main difficulty for each discipline is the question of origin. The preexisting *singularity* in space, and the *primordial soup* on earth are a practical premises from which to hypothesize, but cannot be replicated by scientific standards to produce conclusive empirical data. Let me say here: I am in no way anti science, but I am a strict skeptic (I know, that seems to belie my comments about God). From my perspective, *serious* theologians and hard scientists are not altogether dissimilar. That is, ALL are in search of *truth* or at least an accurate description of reality. Also, ALL necessarily start from unprovable first principles (note: I’m interested in all, but master of none). Thus, my arguments in support of the Bible and suspicion about macroevolution are both qualified by my previous statements. What say you?

 
At Fri Mar 11, 12:34:00 AM 2005, Blogger Apesnake said...

Actually, evolution is analogous to the "unified field theory" in that it makes sense of huge amounts of observations that would be senseless otherwise. If evolution had as little evidence as string theory, even its proponents would not want it taught in schools except for the odd graduate level course in "theoretical biology"

The distinction between macro and micro evolution disappears with time. If micro evolution is allowed to progress for vast numbers of generations the result would be macro evolution.

"Your link notwithstanding, the possibility that distinct species are and have always been distinct is, in my view, discounted without warrant. You seem to accept it’s veracity on the basis insufficient disproof, rather than immutable positive proof."

One of the problems with defending evolution is that one never knows which pieces of evidence would be familiar, understood, persuasive etc. My mention of the fact that I would change my mind if something utterly persuasive came along was not to say that I was not utterly persuaded by the evidence. One has to be ready, in the world of science to reexamine even those beliefs that we consider utterly proven.

As for what evidence is considered conclusive evidence of "macro" evolution; if you are careful enough to decide what the standard for that is you can avoid accepting evolution forever regardless of its veracity. God tells you in person that it is true? - Why, that is no more than hearsay.

If transitional species are considered circumstantial, the criteria for conclusive evidence might need to consist of a living animal that is hatched from a reptile egg, is a reptile on the left side and a mammal on the right and gives birth to live young. Such an observation will never nor can ever be made. Likewise for the soviet bread queue of fossils that show a flip-book of adaptive modifications.

If however you define conclusive as an overwhelmingly large body of observations that one would not expert to see if common descent was false then conclusiveness has been achieved. I will give a couple more examples lower down the post.

Think of gravity, you can not see gravity working but you can make a huge number of observations that support a single description of the phenomenon. No matter how hard you train your telescope or microscope above or beneath the falling apple, gravity can not be observed, only its circumstantial effects. That does not mean we can or should ignore it or treat it as "just a theory" even though our understanding of gravity, how it works and what it does is just a theory, albeit a successful one. What would be necessary to provide conclusive proof of the existence of a phenomenon like gravity? Could falling objects be simply manifesting a temporary (several thousand years old) preference for the center of the earth? Possible. Am I putting off making a commitment about gravity and not walking outside? I think I will chance it ;-)

The fact that all carbon based life forms share common traits is not surprising. I think the logical leap occurs when one insists upon common ancestry.

I am glad you brought this up. It relates to something I only touched on in my last comment, neutral mutations. With the exception of a couple of really primitive extremophile microbes, all life on earth has a language with which it reads DNA to turn it into proteins. Each amino acid building block of a protein is represented by 3 DNA bases (that is the old A,T,C and G). Each protein amino acid, of which there are 20, is represented by a three base "word" called a codon. Now some simple math will show that there are more three-base combinations of A,C,G, and T than are needed for representing the 20 amino acids and the start and stop codes. It turns out that amino acids can be placed on a protein chain in response to different but similar codons. For example, alanine will be placed in the sequence of amino acids if the genetic code is a GCA sequence or a GCC sequence. All but one amino acid are coded by more than one sequence of bases.

Now the fact that almost all living things share the same code is interesting since a specific creator with some kind of forethought could have used a different code for any animal, plant or microbe that she wished. The same protein could be made in both a chicken and a human but when it came time to put in an alanine in the sequence, the DNA would not read GCA or GCC but AAG. The cells of the chicken would put the proper building block in every time even though a human cell would have put in a different one. This would have the added benefit that viruses would not be able to jump from animal to human because there DNA would read as gibberish when the other animals code tried to transcribe it.

But the fact that all species share this code is not the only way that this phenomenon supports the common decent theory.

Because more than one codon can input the same amino acid in a protein sequence, it means that the exact same protein can be spelled with different letters. For instance a protein that has needs to have three alanines in a row will function just fine whether the DNA codding it is spelled GCC-GCC-GCC or GCA-GCC-GCC. The flip of the final "C" to an "A" in the first codon is called a neutral mutation because it does not change the resulting protein. There are other types of neutral mutations like when a codon change does alter which amino acid is used but the new one has the same properties (hydrophobic, charged etc.) so the protein structure and function is not altered. Neutral mutations are not selected for or against so when they occur they just stick around.

What we would expect, if all species have always been distinct would be that neutral mutations would occur at relatively the same rate. There might be some correlation with body size due to radiation and chemical exposure, but there would be no reason to assume that if the same protein is used in a rabbit, a rat (both rodents) and a cat, that the "related" species would have a closer "spelling" of the gene than the cat since the relatedness is just morphological and not ancestoral. If however, the rabbit and rat had a common ancestor and this common ancestor was more recent than the common ancestor of the feline and rodent families, we would expect to see that the cat has protein "spellings" that are less similar to the spellings of either the rat or rabbit than those between the two rodents. The common descent theory would also predict that we could use this as a genetic clock to see how long, comparatively, since two species broke off. It is logical to predict that if there has been common descent and if the fossil taxonomists have done their job relatively well, there should be a strong correlation between the tree of protein spellings and the morphological tree worked out from fossils. Since there are many common proteins to look at there is ample opportunity to test this prediction.

As it turns out this is exactly what we see. Not just for the occasional common proteins in a few organisms but each time a comparison is made. There seems to be only two possible conclusions. All life descended from a common ancestor or someone designed all life on earth in such away that we would have little choice but to conclude it had.

It is many such dichotomies, where we are faced with a choice between the simple theory of common decent and some bizarre world where nothing is as it seems and someone or something is trying to fool us by manipulating our environment, that lead we who believe in evolution to feel it is safe enough to put the "conclusively proven" stamp on the theory and if someone wants us to scrub that stamp off they had better have something really impressive like omnipotent, malevolent elves. And we want to see the elves in person not this "oh, they were here a minute ago" stuff.

As for assuming the primordial soup, that is a separate theory called abiogenisis - that life emerged from non living chemistry. I believe this theory has a good chance of being true given the prevalence of complex chemicals such as sugars seen in interstellar gas clouds through spectroscopy, amino acids found in meteorites and the semi complex hydrocarbons being found in out solar system like on Titan and also given the ease with which organic molecules self assemble. Cell walls are primarily simple bubbles of soap (phospholipids) and auto catalytic chemicals are not at all magical - with those two ingredients plus time and water you are half way to a proto-cell already.

The important thing to remember though is that if abiogenisis turns out to be false or improbable it would not invalidate evolution. The common ancestor could have been a primitive cell dropped in by a meddling God or a hitchhiking microbe on the bottom of an alien's boot. Personally I prefer the soup. Yum soup.

Personally, I think that abiogenisis is true; I am certain that evolution is true. I can not blame others for not being as certain as I am, because much of the evidence is not widely popularized and those who actively oppose the theory are often quite successful in portraying the evidence as weak or non existent. I have some comfort in the fact that I truly believe humanity will one day make its peace with the idea that every organism from the large to the small, from the most beautiful bird to the most revolting intestinal worm are kin. As a 19th century French anatomist once said "There are no monsters-and nature is one."

 
At Sat Mar 12, 03:02:00 AM 2005, Blogger Robert said...

Again, I commend your arguing style. You’ve made the case quite well. As you may know, the are many for whom “theistic evolution” is valid, in addition to those who share your view. From my perspective, most reasonable juries of 12 would likely vote to convict upon hearing your proposition…well done counselor.

I do have one quibble with this: “No matter how hard you train your telescope or microscope above or beneath the falling apple, gravity can not be observed, only its circumstantial effects.” Gravity is instantaneously observable, while evolution is “observed” over time plus historical examination…I think.

At the risk of being misunderstood, here is my position: either evolution is immutable fact or self fulfilling prophesy (not without evidence). I’ll make my point by picking on a renowned theologian (with whom I disagree), who once, in a moment of candor, said: “I really want the Bible and its claims about God to be true”. I could be said that SOME, perhaps not you, really want Darwinian Evolution to be so. If D.E. is fact, the Bible has problems; if the Bible is reliable, evolution (theistic or otherwise) is not. Now, I’m no mindless mystic and my ego is not so sizeable that I can’t countenance ridicule for that which I think. While I hold that either of the two possibilities could represent reality, I lean toward one rather than the other. The basis for this is thorny to say the least. Suffice it to say, what I suggest is an accurate, albeit unpopular, reading of scripture, belies common arguments that support evolution (“All life descended from a common ancestor or someone designed all life on earth in such away that we would have little choice but to conclude it had.” and “some bizarre world where nothing is as it seems and someone or something is trying to fool us by manipulating our environment”) My response to this is complicated by millennia of poor exegesis coupled with layers of pragmatic tradition among divergent communities. I guess I just bristle at dogmatic Darwinism.

I’m right because…I will it to be so. No, but seriously, I won’t bore you with my esoteric recitation of “accurate” theology, unless of course you are interested, in which case I would love to…your move. ;]

 
At Sun Mar 13, 04:23:00 PM 2005, Blogger Apesnake said...

Thanks for your compliment, though I could probably get a jury to believe they were sitting at the center of the earth by having someone hold a lighter outside the window. Juries are soooo stupid. (For all those readers that have ever sat on a jury, I was not taking about you but the dimwits you were sitting next to.) You have obviously but a lot of thought into your position even though we still don't see eye to eye on it.

I have enjoyed pitting my skepticism against someone else's. Even if I disagree with your conclusions, I respect your refusal to simply believe in evolution because others are convinced of it. I will concede that, as you say,

"It could be said that SOME, perhaps not you, really want Darwinian Evolution to be so."

and that some of those who accept and defend evolution (especially online) do not have a full grasp on the theory and of those the worst are the Social Darwinists who have grabbed on to evolution to support their warped world view with absolutely no understanding of the theory just as some new agers have grabbed on to quantum physics and relativity to justify their beliefs because they find the vocabulary and analogies are confusing enough to make them sound scientifically credible - "relativistic quantum entangled healing morphic field water instruction guides" will sell faster than "magic potions manuals" even if brevity requires it to be used only as a subtitle. Social Darwinists have done far more damage to science than any creationist.

This discussion has been quite fruitful for me because in looking around for useful references I found some sites that were useful to me. One of which was a site describing instances of observed speciation including an experiment done in the 80s where a two groups of fruit flys were separated into individual populations, left to reproduce separately for many generations and then tested to see if they had any trouble producing fertile offspring. In the the first group, both populations were kept at identical temperatures, humidity and other conditions. In the second group, the two half populations were kept in different conditions. While the descendants of the first group had no trouble mating with their separated lineage, the second group showed a significant number of infertile offspring, indicating that the genes of the population had changed enough due to environmental selection to begin speciation. A similar phenomenon has been documented in the wild, I believe it was in California where there are two populations of insects that are nearly identical except they are currently occupying different climates. If the males of population "A" mate with females of population "B" there is no problem but if the reverse occurs the reproduction is not successful. Over time, one would expect that any trait which discouraged the individuals from interbreeding would be favored since they would not waste time and energy raising infertile offspring. Changes in morphology or mating rituals could then be selected for. In effect it is an example of partially complete speciation. I mention all this not to bore the jury or to try to convince you but for the simple fact that I find this stuff fascinating.

Perhaps I will leave of for now by addressing one of your points:

"If D.E. is fact, the Bible has problems; if the Bible is reliable, evolution (theistic or otherwise) is not."

The problem is only with the interpretation of the Bible as a work of literal and exclusively divinely inspired history and science. The Bible itself does not claim these to be the only types of knowledge. Parables are used extensively by J.C. himself and no one goes looking for archaeological evidence of historical references to the prodigal son or the man that threw seeds on every type of ground only to find some grew and some didn't. Ironically this guy would have been doing a scientific experiment if he followed it up by asking questions about why the difference in successful growth rates. Just as there are people who believe in theistic evolution, there are Christians who believe in a "Darwinian" evolution without theistic intervention and that the Bible need not be used as a textbook even if it has been for centuries.

I have enjoyed this discussion.

 
At Mon Mar 14, 11:08:00 AM 2005, Blogger Robert said...

"You have obviously put a lot of thought into your position even though we still don't see eye to eye on it."

Back at ya, bro. I propose that we agree to disagree and I look forward to future sparring...both here and my place. You've acquitted your self admirably.

 

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