If you say the lineup of your family members that have lived on this earth under the sun, you're really explaining your genealogy.
This kanji has a second meaning too. It means score. So if you're saying the line up of what happened today under the sun you're really just saying the score of a game. So which is it? Are you talking about the past or something that happened today? That's what makes the difference.
if you can't tell the difference between your genealogy and a game's score you're a fool (ふ) and I can't help you. You aren't a fool, are you? You know the difference.