Human link to Reptiles and Fish Found

May 18, 2006 — The feet of human embryos taking shape in the womb reveal links to prehistoric fish and reptiles, a new study finds.

Basically this study has found that the shape of a developing fetus' feet share many characteristics with those of reptiles. It goes on to say that evolution follows many patterns, which are also shared by a human fetus. It starts with a stage in which the limbs are fin-like, goes on to quadrupedal reptilian limbs, then quadrupedal mammal feet, then bipedal human.

Fetus' Feet Show Fish, Reptile Vestiges

Intruiging, and no doubt controversial. Not so long ago, there was a morphologist named Haeckel, who thought that the fetus goes through forms that the species has evolved through, not in exact detail of course. "Ontogeny recapitulates phylogeny", they would say.

Turns out to not be quite so true, and its lead to some people thinking, for example, that a human fetus has gills when its in its 'fish' stage. Rather, individual organs can sometimes ungergo these 'recapitulation' changes. The human fetus has 'pharyngeal pouches' that are like the ancient gill slits of our fishy ancestors, but aren't fully developed gills, and these pouches are involved in the development (ontogeny) of the lower jar and arms, a process that is seen in the evolutionary development (phylogeny) of the the lower jaw and arms.

Fascinating that they've found this similarity in foot structure. I wonder why the foot should need to develop in such a way.