The Engineering Prowess of the Blood Clotting Cascade

The vertebrate blood coagulation system is a delicately regulated marvel that helps maintain the integrity of the circulatory system. Over 20 years ago, Michael Behe argued it was an example of an irreducibly complex system. Does Behe's claim still hold up today? On this ID The Future, host Andrew McDiarmid speaks with fellow Scotsman Dr. Jonathan McLatchie about his new article series examining recent claims that an evolutionary pathway has been identified for this incredible process. McLatchie is a fellow and resident biologist at the Discovery Institute’s Center for Science & Culture. He holds a Bachelor’s degree in Forensic Biology, a Masters degree in Evolutionary Biology, a second Master’s degree in Medical and Molecular Bioscience, and a PhD in Evolutionary Biology. In their conversation, McLatchie describes how the blood clotting cascade works and why it poses a challenge for evolutionary theory. "Evolution doesn't perform particularly well when you need to make multiple co-dependent mutations," he says. McLatchie explains just how delicately regulated the blood coagulation system is and defends Behe's argument for the cascade, saying it exhibits irreducible complexity in spades. McLatchie also critiques recent proposals by the late biochemist Dr. Russel Doolittle, who claims to show a step-by-step evolution of vertebrate blood coagulation. McLatchie notes that Doolittle helps himself to irreducibly complex components as he attempts to explain its origin, inadvertently helping to confirm Behe's arguments in the process. Read McLatchie's 3-part article series on the blood clotting cascade at evolutionnews.org.