Vital organs gave snakes their venom: An Evolutionary Tail:
A letter in Genome Research states that snake venoms evolved from other proteins in their body so that they could be toxic to other animals. But if such toxins were designed, then wouldn’t it make sense to just tweak proteins already present in animals such that they would become toxic? This shows that it is often very difficult to test between the predictions of evolution and design, and the evidence for evolution is greatly weakened in the face of design. Another interesting finding in the letter is that apparently, relatively minor changes in amino acid sequences can be deadly - literally. In other words, mutations causing changes in proteins can have lethal effects. Continuing along these lines, a system would have to be in place once these proteins were mutated to ensure that they did not "attack" the snake organs themselves from which they originated. This is beginning to seem a bit like multiple mutations and systems are required to be in place prior to utilizing such essentially poisonous proteins. Getting back to the idea with minor changes in the protein, this provides further evidence for the idea of how sensitive amino acid sequencing can - the specification for proteins is rather strict. Considering these aspects of the evidence, design may be a more plausible explanation for what is observed than unguided processes. Recall that simply because of similarity does not prove what process can take credit for what is seen - all other factors that allow venom to be effective, yet properly stored must be considered in an evolutionary explanation for these supposed mutated proteins.
LA Times Questions Power of Mutations: A recent editorial in the LA Times, "Waiting for the Supermutants," highlights the difficulty which mutations have to create beneficial effects in organisms. The author notes that with "6 billion rolls of the dice ... no one has been born with a brain the size of a basketball [and] No eyeballs that see in the dark." While this may be a somewhat unsophisticated view of evolutionary theory, it does highlight an important point: with six billion inhabitants on earth today, every single nucleotide in the human genome should have been mutated several times within this generation. Though beneficial mutations are hard to detect with such small odds, there appear to be no hopeful monsters with large beneficial changes.
Rewriting the History of Evolutionary Thought: A recent letter to nature, What Darwin Knew offers a view of the history evolutionary theory that many would find unorthodox. According to William L. Abler of the Department of Geology at the Field Museum of Natural History in Chicago, the concept of natural selection did not originate with Darwin. Rather, Abler notes that James Hutton penned the concept in his An Investigation of the Principles of Knowledge and of the Progress of Reason, from Sense to Science and Philosophy in 1794, and again by William Paley's Natural Theology in 1803. Paley, thought by many to have developed ideas that were progenitors to the intelligent design movement, apparently considered the possibility that, "that the present world is the relict of ... variety; millions of other bodily forms and other species having perished, being by the defect of their constitution incapable of preservation, or of continuance by generation" but then rejected it.
Speciation and the Pace of Evolution II: A recent article in Science, "Molecular Phylogenies Link Rates of Evolution and Speciation" (301:473), evolutionary biologists have sought to correlate rates of speciation with rates of genetic change since Ernst Mayr proposed the "founder effect" model of speciation. Under the founder effet, a small number of individuals in a population become reproductively isolated from the main population, and thus their genes can found a new population. The authors state that this concept, "formed the basis of the theory of punctuated equilibrium" because it supposedly allowed rapid evolution in small populations. The study attempted to correlate genetic difference with the number of speciation events, and found that they correlated in 15 out of 43 unbiased trees. The authors conclude that, "rapid genetic evolution frequently attends speciation" which seems to confirm Mayr's founder effect model and state, "our results provide both a genetic counterpart to and a plausible link with the observations of punctuated equilibrium of morphological traits reported in the fossil record." The question is what have they really found? The number of "speciation events" is a quantity that assumes there is an unbroken chain of organisms going back go some ancestor. If common dscent is not true, then perhaps the number of "speciation events" is simply an function of the degree of observed differences between one organism and one of its relatives. If descent is not assumed, that would seem to imply on the surface that the significance of this paper is that the genetic distance sometimes correlates with observations about the level of difference between a group of organisms. Such a correlation would be unsurprising. However, this paper seems to assume that speciation entails genetic evolution. This claim is not necessarily held by all evolutionary biologists. Ian Stewart (as discussedin Speciation and the Pace of Evolution I) seems to imply that genetic differences accumulate before speciation events, and it is some shift in the environment that causes instability in a population where it reproductively separates, allowing the two populations to evolve their separate ways. Such a view of evolution would not require that genetic differences correlate with speciation events, because speciation is not the result of some sudden strong selection pressure but of some event which simply divided a population with pre-existing diversity in two. If this paper is correct, however, then one must ask how rapid is the genetic evolution, and is it too rapid for known mutation rates? Evolutionary biology cannot have it both ways: either Part I is correct and speciation allows for slow genetic change (but where are the intermediate fossil forms?) or Part II (this study) is correct and speciation entails rapid genetic change (their results are "attributable to a punctuated molecular clock"). If this study is correct, then we must ask, can genetics produce the increased rapidity in evolution (i.e. is the mutation rate high enough to produce the required rate of change)? (7/23/03)
Speciation and The Pace of Evolution I: A recent article in New Scientist, "How the species became (vol 180 issue 2416)," begins with the observation that, "One of the ironies of Charles Darwin's On The Origin of Species is that while it provides ample evidence that new species evolve from existing ones, it doesn't tell us much about how it happens." The article goes on to note that conceptions of speciation have themselves evolved as it was once thought that, "species formation occurs as the direct result of major environmental and geographic differences" whereas, "[t]he new focus is on situations where speciation takes place without any dramatic changes, in a single interbreeding population of very similar creatures, all in much the same environment." The article observes that "[n]early all publications on speciation in Nature and Science over the past five years or so focus on this undramatic scenario -- a complete reversal of what used to be the case." This is basically because biologists are realizing that allopatric speciation (speciation by geographical isolation) is less common than sympatric speciation (speciation with geographic comingling). Through "symmetry breaking," differences in organisms arise which effectively cause them to be members of different species. Variatian always exists, and when the enviroment shifts to a certain point, instability arises in a population where suddenly some members are favored over others and speciation occurs. This all makes sense but the question is if it can explain the origin of biological novelty and the lack of transitional forms in the fossil record. The author's primary example of speciation is the Galapagos Finch species, which are genetically very similar. Speciation does not incorporate any kind of magical muation, and thus in the case of Darwin's finches, speciation seems to be variation upon a theme--but what about the origin of new themes both in biology and in the fossil record? Small incremental genetic mutations still seem to set the pace of evolution, and seem to be unrecorded in the fossil record and implausible as a means of creationg novel features in organisms.
Lemmings Don't Jump Off Cliffs? You're kidding me! Contrary to very popular belief, lemmings may not jump off cliffs, says a New York Tims article entitled, "Scientists Find Lemmings Die as Dinners, Not Suicides ." Apparently lemming populations do undergo rapid bursts and crashes, but scientists are now attributing this to predation by snowy owls, predatory sea birds, arctic foxes, and the stoat (a weasel-like creature). These scientists have been able to explain population changes as a four-years cycle based upon predation. Interestingly, the popular notion that lemmings commit suicide may be based upon a Disney special, "White Wilderness" in which lemmings jumped off a cliff, and it was apparently documented that the lemmings were purchased from children and then, "herded into the water." This shows how even well-intentioned media can promote false facts in the mind of the public over popular scientific ideas. Perhaps such distortions occur elsewhere. (10/31/03)
Evolutionary Psychobabble? A recent New York Times article, "In Mating Games, Spiders May Learn Lessons Faster Than Young Men," claims that research on spider mating shows that spiders and other animals are often driven towards mates which seem to have had reproductive success in the past. Evolutionary biology can explain this, but the article goes on to claim that human mating behavior is shaped by the same forces. Of course all this assumes that mating behavior in organisms has been driven purely by the forces of nature--i.e. natural selection. While this may be true to an extent, particularly in animals, if the psychological nature of the human mind is indeed designed, then we would expect that naturalistic forces have not been the only ones which shaped human mating behavior. If intelligent design were allowed into the picture, perhaps "intelligent design psychology" could make contributions over evolutionary psychology.
Speciation or Something Else? An article in Science, "Sounds Like Speciation," found that rapidly-arising differences in song-bird songs could lead to reproductive isolation in the matter of one generation. The article calls this "speciation," but one must ask if this "speciation" has involved the origin of any novel biological feature. The answer to that question is no: the standard for speciation appears to be mere reproductive isolation. The two song-bird populations do not interbreed because they sing different songs. Genetically, however, they are nearly identical. The reader should beware definitions of "evolution" speciation that may appear to imply macroevolution, when nothing new is really generated. (8/20/03)
Complex Biochemical Systems Resist Evolution: A recent study in Biomed Central, "A simple dependence between protein evolution rate and the number of protein-protein interactions," shows that the ability of a protein to evolve is linked to the number of other proteins with which it interacts. Although the study was conducted by comparing systems which it assumes evolved, it concluded that, "protein-protein interactions tend to slow the rate at which proteins evolve." This implies that complex biological systems resist change because change tends to destroy functionality. Perhaps this hints that irreducible complexity might be lurking in the cell. (5/23/03)
Limits to Genetic Change: A recent paper in Science, "Low Potential for Climatic Stress Adaptation in a Rainforest Drosophila Species," indicates that fruit fly populations subjected to "intense selection for over 30 generations" "lack the ability to evolve further resistance." This seems to imply that even under extreme selection pressure, there are inherent genetic limits the amount of change possible in an organism. The abstract concludes that, "[t]he low potential for resistance evolution highlights the importance of assessing evolutionary potential in targeted ecological traits and species from threatened habitats," implying that species just can't naturally evolve very far very fast in response to even severe environmental changes! This has strong implications that there are limits to how far a species can evolve. (7/8/03)
Origin of Eukaryotes: "The origin of the eukaryotic cell: A genomic investigation", a paper in PNAS by Hyman Hartman and Alexei Fedorov shows eukaryotes contain 347 proteins without homologs in supposed bacteria and archaea ancestors. This challenges the hypothesis that eukaryotes formed through a simple merging of bacteria and archean cells. Authurs suggest a new pre-cursor cell type--the Chronocyte--merged with members of both the archea and bacteria domains, making the evolutionary origin of eukaryotes a much more complicated and less elegant theory. Engineers Ask Nature for Design Advice by Jim Robbins for the New York Times
Researchers Not Monkeying Around: Can Infinite Monkeys on Infinite Typewriters Type Shakespeare? A recent CBS News article, Monkey Theory Proven Wrong, reports that if so, they're off to a slow start. British researchers who left a functioning computer in a monkey enclosure found that before urinating and defacating on the keyboard, "the lead male got a stone and started bashing the hell out of it." Eventually some of the more scholastically inclined started playing with it, and produced about 5 pages of text, "primarily of the letter S." Click here for the full article. (5/10/03)
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