Actually, according to the bible Adam was not the first man. When he was created the earth was already populated. Genesis clearly tells us that God created two races of man - one in his own image, and one from the dust of the ground.
Genesis 1:26 And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.
Note this verse says 'them' and not 'him', indicting a race of men.
Then in:
Genesis: 2:5 ..........and there was not a man to till the ground.
(How strange. God had just created man and yet there was no one to take care of the crops).
Then it goes on:
Genesis 2:7 And the LORD God formed man of the dust of the ground and breathed into his nostrils the breath of life; and man became a living soul.
It seems the race of Adam was created to serve the man who was already there.
The Bible doesn't tell us about the people of Nod because initially it only narrates the history of one family.