[ReignOfError]

I'd like to know how something can be "related" to another biologically without in some way "descending" from it.

I am closely related to my sister. She is not my mother. My niece and nephew are related to me, but they are not my children. This isn't very complicated stuff.

[Fester Chugabrew]

So then, what does "common descent" mean, if not some kind of relationship? I sense a semantic shell game here.