MICHAEL BEHE: In Darwin’s Black Box: The Biochemical Challenge to Evolution I devoted a chapter to the mechanism of blood clotting, arguing that it is irreducibly complex and therefore a big problem for Darwinian evolution. Since my book came out, as far as I am aware there have been no papers published in the scientific literature giving a detailed scenario or experiments to show how natural selection could have built the system. However three scientists publishing outside science journals have attempted to respond. The first is Russell Doolittle, a professor of biochemistry at the University of California at San Diego, member of the National Academy of Sciences, and expert on blood clotting. Second is Kenneth Miller, a professor of cell biology at Brown University and author of Finding Darwin’s God (Miller 1999). The third scientist is Keith Robison, who at the time of his writing was a graduate student at Harvard University. I will give their arguments below and my response. Here is a brief summary. 1) Professor Doolittle argued that new laboratory work showed two components of the blood clotting cascade could be eliminated (“knocked-out”) from mice and the mice got along fine without them. However, Doolittle misread the laboratory work: the double knock-out mice have severe problems and have no functioning blood clotting system. They are not models of evolutionary intermediates. Although anyone can misread a paper, in my opinion the fact that an expert cited a recent and contradictory journal article, instead of a publication directly addressing the evolution of blood clotting, shows that there are indeed no detailed explanations for the evolution of blood clotting in the literature and that, despite Darwinian protestations, the irreducible complexity of the system is a significant problem for Darwinism. 2) Although embedded in a lengthy description of how blood clotting and other systems work, Professor Miller’s actual explanation for how the vertebrate clotting cascade evolved consists of one paragraph. It is a just-so story that doesn’t deal with any of the difficulties the evolution of such an intricate system would face. Even so, in the one paragraph Miller proposes what looks like a detrimental or fatal situation, akin to the knock-out mice (above) that lack critical components. 3) Keith Robison proposed that a cascade might begin with a single enzyme with three different properties. Upon duplication of the gene for the enzyme, the duplicate loses several of the properties, resulting in a two-component cascade. Repetition of the scenario builds cascades with more components. Although intriguing, the scenario starts with a complex, unjustified situation (the enzyme with multiple abilities) that already has all necessary activities. What’s more, the proposed gene duplication and several steps needed to lose function are “neutral,” unselected mutations. Stringing together several very specific neutral mutations to build a complex system is vastly improbable and amounts to intelligent design. trueorigin.org/behe03.asp
Posted on: Tue, 08 Jul 2014 04:02:12 +0000
Trending Topics
Recently Viewed Topics
© 2015