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Debate: 15 questions for evolutionists (view source)
Revision as of 18:41, January 25, 2012
, 18:41, January 25, 2012→What an evolutionist would say
===What an evolutionist would say===
===What an evolutionist would say===
DNA is not a code, which is encoded information intentionally transmitted by an intelligent agent. The "information" present in DNA is the result of natural selection, which screens out DNA sequences unsuited to reproduction and increases the frequency of those which are useful. The result is a highly complex molecule capable of a large variety of functions, but it is still a chemical, obeying the laws of physics and chemistry in a highly predictable way.[[User:TonyPark|TonyPark]] 15:55, 12 January 2012 (EST)
DNA is not a code, which is encoded information intentionally transmitted by an intelligent agent. The "information" present in DNA is the result of natural selection, which screens out DNA sequences unsuited to reproduction and increases the frequency of those which are useful. The result is a highly complex molecule capable of a large variety of functions, but it is still a chemical, obeying the laws of physics and chemistry in a highly predictable way.[[User:TonyPark|TonyPark]] 15:55, 12 January 2012 (EST)
::TonyPark is right again! There is no such thing as the "DNA code" (at least Dan Brown hasn't published it yet). A cell is a biochemical system, similar to how a car is a mechanical system. Actually, if examined closely, most biochemical systems are remarkably mechanical in function. The set of biomolecular actions in any cell, while they may seem quite complex, are actually quite predictable once they are well understood. This is one of the driving principles in modern cell biology, molecular biology, developmental biology, pharmacology, medicine (notably oncology), bioinformatics, and every other field (there are hundreds) that deals with functional genomics, proteomics, or metabolism.
::Genes are referred to as "information", even studied as information (bioinformatics), because that is a convenient way to model and discuss a very complex system. The article on [[genes]] here at Conservapedia is actually pretty well written (when I have time, I do want to tweak a couple minor points in that article, but that is something I will discuss on that article's talk page), I would encourage anybody reading this argument to read that article first if they are unfamiliar with the terms I am going to use.
::In the context of this question (and the "answers" posted by CMI), "DNA code" is a very arbitrarily defined term. The trouble is that the interactions between DNA and the biomolecular mediators of cellular homeostasis (the processes that maintain the tightly controlled cellular microenvironment) are quite complex. It is a gross oversimplification (in fact, it is incorrect) to say that DNA ''only'' functions as a "template" to be transcribed into mRNA and then translated into protein. It is true that a similar-sounding term, "genetic code", refers to triplets of bases (codons) encoding for particular amino acids in a protein product. However, there is a lot more that goes into regulating cell processes than blind protein production. Gene expression is a very tightly regulated process ensuring that only the right cells express the right genes at the right time (for a good example of when this goes wrong, see [[cancer]]). This regulation is highly mechanical. To avoid launching into a lengthy discussion of gene regulatory mechanisms, I will leave the point at that.
::Accordingly, I will give the authors of this question the benefit of the doubt and interpret "DNA code" to mean the sum of homeostatic regulation via direct and indirect biomolecular interactions with DNA. On the whole, this question is so broad in scope that it ''is'' impossible to properly answer without several thousand pages of text. To illustrate this point, I have a five volume reference book on my bookshelf that summarizes most of the human biomolecular signalling pathways that were known when it was published (2006); in total, the book is 5300 pages long. Given the pace with which biomedical scientists are unraveling the human interactome, a 2011 edition would need to be '''at least''' twice as long (and require a giant team of very masochistic editors). The simple fact here is that '''every''' chemical process within the cell can (and does) elicit some downstream effect on gene regulation. Therefore, one cannot even ''functionally'' explain the "DNA code" without also explaining every last scrap of chemistry that goes on in a cell. Similarly, thoroughly explaining its origin would require tracing the phylogeny of several hundred thousand individual processes.
::While creationists may rejoice at the "impossibility" of this question, science is not at all clueless about the evolutionary origin of many of the more central parts in this system. Quite the contrary actually. For instance, the evolutionary origin of introns in eukaryotic genes from ancient self-splicing bacterial transposable elements (which seem to have been retroviral in origin) is practically an air-tight case. The highly conserved sequence homology among members of the most common families of transcription factors (proteins that directly interact with DNA to regulate genes) also strongly hints at the existence of a common root at the base of each family "tree". An even better example is the remarkably high level of homology between the transcriptional machinery in all extant lineages of life. Similarly, there is the striking homology in translational machinery. In fact, sequencing of ribosomal RNAs (which are under quite a bit of selective pressure to stay '''very''' static) is a very accurate way to estimate ancestral relationships--oh, and for most clades examined, the "newfangled" rRNA data suggests ancestral relationships that are very similar to (and in plants and animals, often identical to) those suggested by older techniques based on phenotype. All the examples that I just gave are evidence of the common descent of the gene regulatory / expression machinery. Clearly, without going back to the origin of life itself (which is an impossibility), explaining the evolutionary origin of the obscure <s>creationist invention</s> concept that is the "DNA code" is fundamentally impossible. However, just because scientists can not precisely trace every last bit of cellular machinery all the way back to the origin of life (which is the rather disingenuous implication of this question), does not mean that that the scientific community is at a loss for evidence from which to make logical inferences about its approximate naturalistic origin.
::Like question number 1, question 2 ignores the fundamental principles of the scientific process; conclusions and hypotheses regarding an un-observable process must strictly rely on logical consideration of the available evidence. The sound practice of science (which, I might add, is meticulously ingrained in any scientist-in-training and '''very''' strictly enforced by peer review) requires that evidence is objectively interpreted as only speaking for itself, independent of presupposition or ideological dogma. Science is not about searching for evidence in support of a particular hypothesis; in fact, it is about seeking evidence which contradicts the working hypothesis, so that the working hypothesis may be further refined. It is for this simple reason that "creation science", by relying on the '''presupposition''' of divine creation, is not science. A scientific theory, such as evolution or relativity is not a presupposition (as will be claimed in a couple later questions), rather it is a logical paradigm that is compatible with the hypotheses suggested by the available evidence. Scientific theories are, by definition, fluid logical paradigms; when the evidence suggests a paradoxical conclusion, the theory (not the conclusion) is adjusted to accommodate the new finding. --[[User:JHunter|JHunter]] 13:41, 25 January 2012 (EST)
===What a creationist would reply===
===What a creationist would reply===