The easy way to get asymmetry is the "winner takes all". Why we have 5 fingers? 6 is probably a good number too. Cartoon characters have 4 fingers and they seem to do fine. Why all 5 and not a mix?
The answer is that there was an old fish with 5 whatever in it's fins, and the offspring conquered the land and evolved and now we have 5 fingers. If a 4 whatever fish tries to do the same trick, it will face a strong competition an if the offspring ever reach the technological level to create a small country, we would nuke them from orbit.
The answer is that there was an old fish with 5 whatever in it's fins, and the offspring conquered the land and evolved and now we have 5 fingers. If a 4 whatever fish tries to do the same trick, it will face a strong competition an if the offspring ever reach the technological level to create a small country, we would nuke them from orbit.