DTT, the first two sentences in my paragraph above should not have been necessary, but obviously they were. Though not of modern styling (and you chose the KJV for your quote, which is early 17th Century English), Genesis 6-9 are the full account of the Flood. The writer of Genesis made clear in the two verses Jac quoted exactly what Noah was commanded to do. It may simply be that in writing the less complete and simpler accounts of the command given Noah and the embarking of the animals, the writer thought it unnecessary to spell out the exact details each and every time. IOW, the writer relied on the memory of those who would read it.But the part of scripture I quoted clearly says two of each kind (whether clean or unclean) If my bit is wrong, why is it in the bible?
That Leviticus has the first recorded definition of "clean" and "unclean" animals - the definition given to Israel - does not preclude Noah knowing what God meant. It just means the writer of Genesis didn't record how Noah acquired that knowledge.And if your bit is right, how did Noah know about clean and unclean animals, given that Leviticus - in which such things are described - hadn't been written?
Another point my daughter made to me, besides what Jac pointed out, is that Noah, his family, and the animals were on the ark for nearly a year. It is entirely possible that the ark's population at the end of that year might have been greater than it was at the start. Need I explain?