Along a similar line...
Star trek Next Gen had an excellent episode that explained why all the sentient races looked so similar...
Billions of years ago a sentient species- the very first one- seeded the galaxy with life, genetically pre-programed to evolve to a common goal- something resembling the first ones...
It was one of the deepest episodes they did...
https://en.wikipedia.org/wiki/The_Chase_(Star_Trek:_The_Next_Generation)