why most animal facial structures are the same

Question

Why are most animal faces eyes at the top, nose in the middle, and mouth at the bottom? How are they all so similar?

In: 16

Answer 1

We are deuterostomes, a minority in the animal kingdom, whereas the vast majority of animal life belongs to the Protostome group (e.g. arthropods). The gut plan between the two groups is reversed, which means our “face” developed on the end of the gut plan where protostomes developed an anus, and Vice versa. So while both groups developed a “head” with “eyes” positioned above a “mouth,” that was just an example of convergent evolution, because those features developed from completely different features.