The evolutionary claim is that the one-chambered heart pump evolved first, and then it evolved into the two-chambered heart, then the three-chambered heart, and finally, the four-chambered heart, which is used in all mammals. In short, evolution postulates that the circulatory system evolved from a simple system in bacteria to the complex system in humans by the natural selection of billions of mutations (Bishopric 2005). However, the major insurmountable problem is that each type of heart is an integral part of a specifically designed complex circulatory system. To function properly, each type of heart and circulatory system works together and very differently from all the others. As a result, how one type of system evolved into the next type has baffled Darwinists. Not even plausible "just-so" stories have been proposed to explain how one heart system evolved into a very different system. Evolution is unable to explain their origin.