“Two chemicals called actin and myosin evolved eons ago to allow the muscles in insect wings to contract and relax. Thus, insects learned to fly. When one of those paired molecules are absent, wings will grow but they cannot flap and are therefore useless. Today, the same two proteins are responsible for the beating of the human heart, and when one is absent, the person’s heartbeat is inefficient and weak, ultimately leading to heart failure.Again, science marvels at the way molecules adapt over millions of years, but isn’t there a deeper intent? In our hearts, we feel the impulse to fly, to break free of boundaries. Isn’t that the same impulse nature expressed when insects began to take flight? The prolactin that generates milk in a mother’s breast is unchanged from the prolactin that sends salmon upstream to breed, enabling them to cross from saltwater to fresh.”