Clean Animals

In Gen 3, After Adam and Havah eat the forbidden fruit, Adonai makes a sacrifice and coveres them with skins.
Later in Gen 4, Kayin and Hevel offer sacrifices, Hevel's sheep offering is accepted
But in Gen 7, when Adonai is telling Noach which animals and how many to take in the ark, it's HERE that we first learn about Clean and Unclean animals. Now, it's not elaborated on, we don't know which animals are clean and which are unclean at this point, but I'm sure Noach knew which ones were considered clean.
Now isn't this interesting, seeing as at this particular point in time, Adonai has only given plants as food for Man, so clean and unclean clearly doesn't have anything to do with food at this point. Rather, I'm sure it has to do with offering sacrifices (I haven't gotten to this point in my writing yet, but I know it's there in a few verses.).

I also thought it was interesting that Adonai says that Noach is to take seven couples of the birds too. Let me find it for you

Genesis 7:3 also of the birds in the air take seven couples - in order to preserve their species throughout the earth.

Isn't that interesting. Take seven couples for clean animals, one couple for unclean animals, and seven couples for birds of the air. Wonder why?