Ch 4: Teeth Everywhere

I have to say that this chapter is by far the most interesting. I never realized or even thought about the possibility of an organisms teeth telling you about their eating lifestyle. Shubin clearly describes the difference between a mammals teeth and a reptiles. He describes that, "[...] whereas many reptiles have similar teeth, those of mammals are distinctive" (Shubin 61). I truly like how Shubin shows how some of the fossil teeth he and his team discovered are similar to say that of a dog. His comparisons really help me visualize how some organisms can have similar bone structure. He answered all my questions the questions about why hard bones came about by stating, "[...] Hard bones arose not to protect animals, but to eat them" (Shubin 76). Once again, Shubin's diagrams helped me visualize jawless creatures with a diagram of Conodonts. Also, his diagram of the Ostracoderms helped me visualize their head region covered by a big disk-like shield of bone. I found this chapter most interesting because I discovered that all animals are related in some way such as teeth. Also, I found this the best chapter because Shubin summarized all of the past three chapters and showed how they were all related to chapter four. He stated a theme, "A theme of these first four chapters is how we can trace the same organ in different creatures" (Shubin 80). He made me realized that different versions of our organs, DNA and genes, bones, and teeth are found in every creature. That made me realize that all creatures are one in the same but just have modified characteristics depending on their environment and eating lifestyle.