system
Given the following post, respond as if you're commenting on Reddit:
human
Do scientists believe that all life as a single ancestor?

I'm not sure if I'm able to word this in a way that gets my point across, but even if all life comes from the same *general* configuration of proteins and what have you, is the prevailing theory that there was one "organism" that started it all and then split into everything else, or that across the globe multiple, similar organisms formed under similar conditions in primordial goo?
gpt
The current best accepted theory is that all life on earth shares a single common origin. We are reasonably confident that all extant cellular life has a common ancestor dating to around 3.5 billion years ago, typically designated as the Last Universal Common Ancestor or LUCA. This would most likely have been a communal-living single celled organism not entirely dissimilar to a bacterium. The origin of life predates the existence of the LUCA by around 1 billion years and to begin with this is unlikely to have been celular in origin. Nevertheless given what we know of evolution and biochemistry we can be confident that the abiogenesis of life on earth was a singular event from which all life has since descended. If there were competing abiogenesis events 4.6 billion years ago then we can see no evidence of them today.

Edit : the biochemical origin of life likely predates the existence of the LUCA by between 0.2 and 0.8 billion years.