The truth of that statement is presently unknown. All that's known for sure is that all life we've found so far shares a common ancestry. It's possible there

The truth of that statement is presently unknown. All that's known for sure is that all life we've found so far shares a common ancestry. It's possible there were multiple abiogenic sources of life and the one we see now just out-competed everything else. So maybe the first living thing has no ancestors alive today.