In another thread, Tosca was expressing skepticism that all living organism on this particular planet share a common ancestor, so I told him to do some research in that regard. He wanted a new thread instead, somhere it is. Let’s start with an article that does not get real deep into the topic but gives a good overview:
Ancestor of All Living Things More Sophisticated than Thought | Live Science
Here are the first few paragraphs of the article:
“The mysterious common ancestor of all life on Earth may have been more complex than before thought — a sophisticated organism with an intricate structure, scientists now suggest.
The last universal common ancestor, or LUCA, is what researchers call the forerunner of all living things. Much about LUCA remains enigmatic — many think it was little more than a primitive assemblage of molecular parts, a chemical soup from which evolution gradually built more complex forms. Some even debate whether it was even a cell. [Theories on Earth's First Life]
Now, after years of research into a once-neglected feature of microbes, scientists suggest the last universal common ancestor was indeed complex, and recognizable as a cell.”
In addition, It has been estimated to have lived some four billion years ago, when Earth was a mere 560 million years old.
There ya go, Tosca. Have at it.
