Fish Chapter 14 Summary

Chapter 1:

1: The author and his colleagues chose to focus on 375 million year old rocks because they were looking for a missing link. They had found fish without amphibious qualities in rocks 10 million years older than their focus age, and 10 million years later the focus age they had found amphibians that looked different than fish. Thus sending them on the search for a missing link. The type of rock these fossils where found in were sedimentary because sedimentary allows the fossil to be preserved inside of it. The igneous and metamorphic rocks are formed from lava and extreme heat/pressure (igneous formed by lava and metamorphic formed by intense heat and pressure).

2: Tiktaalik had a flat head with two eyes on it, fins, and a flexible neck. It was the missing link of life evolving from water to land. It filled in the

Chapter 5:

1: Both the trigeminal and facial cranial nerves are the most complicated because the start from the brain and split into different parts of the body.

2: The structures are the ears, larynx, throat and jaws.

3: The Hox genes are like blue prints for development for embryos. They are important because without them the embryo wouldn’t know how to develop.

4: Amphioxus is a small invertebrate, yet shares many characteristics with vertebrates. It is a good specimen to study due to its similarities and differences with vertebrates. I characteristic I share with this critter is a nerve chord.

Chapter 6:

1: The three germ layers are ectotherm (forms the epidermis, nervous tissue, and sense organs),endotherm (forms gastrointestinal tract and lung muscle), the mesoderm (forms circulatory tissue, muscle and bone).

2: When the fertilized egg continues to divide and the inner cells develop into an embryo and the outer cells protect