Chapter Five: Getting Ahead

Shubin started the chapter with the detailed description of human brain. Though the brain structure was complex and chaotic, author's descriptions helped me visualize the appearance of the anatomy. While learning about the different nerves, it was interesting to learn the names of each facial nerves, such as anguli oris and corrugator supercelli. Like previous chapters, Shubin continued to compare the human bone structures to those of other creatures. "If we follow the gill arches from an embryo to an adult, we can trace the origins of jaws, ears, larynx, and throat. Bones, muscles, nerves, and arteries all develop inside these gill arches" (96). Knowing these facts, doctors use the information to predict and prevent birth defects. Another interesting fact was that a shark embryo and a human embryo share similar appearances and functions, which helped me understand Shubin's theory of our inner fish.
Amphioxus and Haikouella (over 530 million years old) share similar anatomy; Both worms have notochords, a nerve cord, and gill slits. These worms are known as the earliest creatures with notochords and nerve cords. Scientists use this information to prove the revolution of species, since some of human body parts come from these worms. This chapter amazed me once again about the origin of our body and bone structures.