Adam and Eve
The first man, from whom we are all descended, is traditionally called Adam. The Bible does not tell us what his name was, or even whether he had one. When it calls him ha adam, that is just the Hebrew for the man. But it serves as a convenient nickname.
According to the Bible, God appointed Adam as humanity's representative in its response to its task, with the first woman and all their descendants as members. This meant that Adam's decision to comply with God's law would entail that humanity as a whole would comply.
Was this choice really made in the mind of one man? I think so, though the truth may be more complex. At any rate, it is a convenient way to express the dire reality of the current human condition. Much effort has gone into trying to devise an interpretation of the story of Adam that retains the truth it conveys about the human condition while being less of an affront to the prevailing modern paleontology. I cannot say that I am convinced by any of these, and I suspect that prevailing modern paleontology is less true than its practitioners suppose. However, these details are not important.