The Remarkable Fossil of the "Fishapod," Tiktaalik, Which Lived About

Essay

The remarkable fossil of the "fishapod," Tiktaalik, which lived about 375 million years ago, is a beautiful example of an intermediate form, having the attributes of both fish (scales, fins) and tetrapods (a flat head, mobile neck). The presence of Tiktaalik and other fossils of other organisms that lived around the same time shows clear evidence that tetrapods were derived from fish, implying that the grouping "fish" is paraphyletic. Imagine now that there was no fossil record. Would it still be possible to determine whether or not "fish" is paraphyletic?