Henotheism in the Hebrew Bible.

[LinuxGal]

But the purpose of the generations of Adam is to show a direct line between him and Noah - it has no other purpose. The purpose of the generations of Noah is to show the men who peopled the Earth after the flood. You’re attempting to apply the same reasoning to two different things.

A list of Noah’s children and grandchildren doesn’t serve the same purpose as a list of Noah’s male ancestors in direct lineage. 

And if you weren’t so quick to sneer at semantics, you might understand why you’re getting this wrong.

Boru

That wasn't it's purpose at all, it was tracing the lineage of the firstborn sons, Noah just happened to be one of those firstborn sons.