My inner fish

Your Inner Fish is a TV series about evolution. It goes back to fossils, and explains how ancient species changed throughout evolution. In this TV series, we learned about how biologists found the missing links in evolution. We learned about fish moved from sea to land in out evolution unit, and this show tells us how scientists found the bones from the missing link. Also, we learned about the long bone, short bone, many bones layout. This show discusses this to a further extent. To elaborate on the question related to the sonic hedgehog, it is basically a little cell giving out a signal where to stop. If that little signal emitter is removed, then the arm basically mirrors itself because it didn't know where to stop. This can prove to be useful, but also shows up on accident sometimes. Elaborating on the question regarding the hybrid land/ocean animal, basically it's limbs changed length in order to accommodate land movement. It's bones got longer, and shoulder got more motion. This allowed it to be much more mobile on land, and even lay down as if it were doing a push-up.