Ch. 2: Limbs

The hand is probably the most interesting and unique part of the human body. I like the way that Shubin comments how the "...hand is a visible connection between us"(29). We use our hands for endless uses. If we desire to make a sandwich, we use our hands to grab the bologna, lay the lettuce, squeeze the mayonnaise, spread the pickles, all done with the biomechanics of the hand. One way that I envision the hand as a reflection of us is how we use them to communicate with others with gestures. When we're angry, we cross our arms. When we're beckoning someone in a kung-fu fight, we curl our fingers back and forth to provoke them. It's amazing how the human hand reflects who we are. As Dr. Shubin is amazed at the different motor connections between the hand as it bends, extends, and twiddles, I too am also amazed at it. I am so fascinated how the opposable thumb helps out in so many of our everyday functions, without it we would not be able to write with a pencil! Hmm, I wonder how humans and other animals have opposable thumbs while some creatures like rats do not? I would have to do more research to find that answer.

What I found astonishing was the earliest limbs found on the Acanthostega gunnari. I thought that since limbs developed for this creature to help swim, could humans eventually develop new limbs for additional functions? Imagine, if we sent a family of humans to live underwater that in a billion years, after mass reproduction, these humans will eventually develop limbs to swim and breathe underwater, just like a mermaid! The water environment helped shape Acanthostega gunnari, so we should expect to see more creatures (including humans) to develop new limbs in the billions of years to come. For example in the future if global warming becomes severe humans may have less hair on their bodies and may develop an umbrella-looking limb to keep them cooler. I may be overspeculating but you never know!
-Benni Vargas