YIF: Chapter 3

            This chapter brought embryos and eggs to show some of the biology of evolution that occurred. They did this by mentioning and describing and relating ZPAs, zones of polarization activity, which are essentially a patch of tissue that causes the pinky side to be different than the thumb side. Then the author went on and said that many animals, including humans, have the ZPA. Then scientists were curious so the wanted to see if the adding of another animal’s ZPA would cause to same result of adding the same animal’s ZPA to another ZPA and surprisingly it did. This was probably the part that most interested me as it justified, scientifically, the relationship of animals to each other using genetics. It is so intriguing to see that this was one of the first ways that scientists used to prove that different animals have similar genetic makeup. More specifically the part where they took a mouse’s ZPA and put it near the ZPA of a skate’s and the two reacted as if the two ZPA were from the same animal, which is an example, to what was mentioned above. This shows scientists that the genetic material of humans is similar to the animals that we already have seen similarities to. This just strengthens the fact that humans share a common ancestor to other animals. This is also the idea that can be drawn by relating this chapter to the Big Idea of biology, the process of evolution drives the diversity and unity of life. The overall essential question that can be made based off of this chapter is, “What is the relationship between genetics and evolution?”