Serendipity is the way to make discoveries, by accident but also by sagacity, of things one is not in quest of. Based on experience, knowledge, it is the creative exploitation of the unforeseen.
For a finite-size system to persist in time (to live), it must evolve in such a way that it provides easier access to the imposed currents that flow through it.
The fact that the same proportionalities rule optimal running, flying and swimming is not a coincidence rather it is an illustration of the fact that a universal principle is involved.