Land-vertebrate blood circulation
From EvoWiki
Suboptimal design > Land-vertibrate blood circulation
This starts off in fishlike fashion and gets reorganized, with some aortic arches and other vessels dropping out. Likewise, the heart starts off as a two-chambered, fishlike heart and becomes split into a three-chambered heart and sometimes further into a four-chambered heart with two separate blood paths. But why not start out with some intended final state if that is what is desired? Why build some extra blood vessels, only to throw them away? Why not make the heart start off as three- or four-chambered?
