I prefer to look at it from the other angle, which is that all vertebrates are fish. I had a professor who was mainly an ichthyologist, but overall a really ol

I prefer to look at it from the other angle, which is that all vertebrates are fish. I had a professor who was mainly an ichthyologist, but overall a really old school natural historian. He always said that we were all just highly derived fishes. If you spend any time at all looking at evolutionary biology, it really does hold true. Bones in our heads can be traced back to the gill arches in bony fish. The pelvic girdle and shoulder bones developed from the pelvic girdle and pectoral bones of early fish. We're really just fish adapted to land.