Are There Other Origins of Complex Life?

All complex life that we know about shares this common ancestor. Once it arose, we think, about two billion years ago. But there's no evidence at all that there was other origins of complex life. So why? Well, i think ii went backt why is life the way it is? And those traits arise because selection is switched from being about outside world to inside world. That's why we end up with two sexes and so on - they can all be traced back to that relationship. I would be shocked if it happened once. It probably happened thousands of times, millions of times, who knows. The thing is, it only survived once aad and only took over the world