system
Given the following post, respond as if you're commenting on Reddit:
human
Considering that all organisms on earth seem to have a common ancestor is it safe to say that abiogenisis only occurred once? And if that is so, why hasn't it happened more than once?
gpt
Considering how quickly life emerged after the Earth became stable, it's unlikely it has happened only once. However, we really only have one data point, and there is still a lot more to do before we can say anything with high confidence.

The reason we don't see multiple sets of life *probably* isn't because of lack of abiogenisis - but rather, whenever new life does emerge, it finds itself in a world with competition that has had billions of years to evolve. It wouldn't stand a chance.

Again though - the best answer anyone can give you on this is just speculative.