Chapter 5: Getting Ahead

In this chapter, Shubin discuses the anatomy and  the connection between human and sharks. He mentions that the basic structure and blueprint of the human head is similar to those of a shark and worm. The four different arches that compose the significant blueprint of heads make it easier to understand the perplexing structure. Each arch is made up of cells that builds the different parts of our skull. The trigeminal and facial nerve control the muscles and carry sensory information from our face back to our brain. The muscles controlled by the trigeminal include those we use to chew as well as the muscles inside the ear. The different intricate nerves each plays a different role in our face, allowing us to smile, to frown, to raise and lower our eyebrows, to flare our nostrils, and so on. I was also shocked when I read that these headless worms are somehow related to the origin of humans. Humans and worms both share gill arches supported by an amphioxus. Never would I have thought we were similar to worms, which are far less complex.