30 August 2010
Your Inner Fish
Your Inner Fish, by Neil Shubin, is a journey into the 3.5- billion- year history of the human body. It is filled with many interesting topics covering the subject. The four topics I liked from it were: Getting a Grip, Handy Genes, Teeth Everywhere, and Adventures in Body Building. I feel these topics gave key information about our past.
Chapter 2, Getting a Grip, talks about the connections between the human and other creatures’ limbs. It also talks about Shubin’s fossil, Tiktaalik, and the unique specialized limbs it had.
Ours hands have long fascinated scientists because of the complexity in them. Sir Richard Owen was a great anatomist who searched for a divine order within bodies. He defined homology in 1843, which is defined as the same organ in different animals under every variety of form and function. For example, a bat’s wing, a seal’s flipper, a cat’s paw, and the human hand all display a common plan of structure. These examples all show identical arrangements of bones and muscles.
During a 2004 expedition of Shubin’s, he discovered the fossil, tiktaalik. It had a joint at the end that had spaces for four other bones, which scarily looked like a wrist bone. They then discovered a whole fin in one block they had found. It was a fin that had “that” kind of bone. It attached four more beyond. This 375- million- year- old- fish had a wrist. It was part limb and part fin. They then discovered tiktaalik had a shoulder, elbow, and wrist composed of the same bones as a human. This meant tiktaalik was capable of doing push- ups.
As Owen described, we humans have connections to some creatures in the design of the hand. Both display a common plan of structure. Shubin’s fossil, tiktaalik, shows the same structure of its fin as a human.
Chapter 3, Handy Genes, discusses how our bodies are filled up with hundreds of different kinds...