Chapter 2: Getting a Grip

I found it clever how Shubin transitioned from the cadaver's hand into a reflection of how our ancestral limbs came to be. The discovery of many different ancient fish with their complex names was confusing to me, and so I had to reread the chapter a couple of times before I understood what each fish signified or did not signify. After realizing that "digits" meant fingers, I finally understood the situation. For example, Shubin sought a fish that showed signs of the transition and evolution of limbs for terrestrial survival. Thus, creatures like the Ichthyostega were irrelevant because although they showed similarity between fish and amphibians, its more modern toed and fingered limbs did not give strong enough evidence that their limbs had been adapting to a terrestrial environment. Thus, it took the discovery of the Tiktaalik's fin with the bone structure of a full limb (unlike the Eusthenopteron's fins with only digits and the one bone-two bone structure) to demonstrate the fin's adaption to today's flippers, wings, and arms. As a result, I learned that appearance isn't the most important similarity that connects creatures with their ancestors, but their bones.