God used two arks in the early lives of His people.  One was to save them from the world-encompassing, cleansing flood.  The other was to save them from eternal damnation.  After creation of the world and eviction from Eden, the peoples of the world grew increasingly bad. At one point, it was so bad that God was grieved.  Genesis 6:6-9 Verse 6 says: " The LORD was grieved that he had made man on the earth, and his heart was filled with pain. " Verse 8: " But Noah found favor in the eyes of the LORD."  Verse 9. ... "Noah was a righteous man, blameless among the people of his time, and he walked with God."  This time God had Noah build an ark with instructions that upon completion he was to load it with his wife and sons with their wives along with a boat load of animals.  Thus the animal part of God's creation was saved from destruction. The second ark was quite different but had a similar function - to save God's creation...