My Baptist friend asked me the difference between Catholicism and Christianity?

I told him that was like asking me what the difference between Coke and Coca Cola Clic because Catholicism is the oldest and most popular form of Christianity just like Coke Clic is the oldest and most popular form of Coke. He got mad and said that wasn't true because the first Christians were more like Baptist but they dissapeared for 1700 years. My question I guess is if that is true that the early Church was more like Baptists than Catholics why are all groups that are descended from that early Church, ie Catholic, Orthodox, Coptic, Armenian etc., why do they all ask Mary and the Saints to pray for us, have a deacon, priest, bishop hierarchy system, have a literal interpretation on Body and Blood and a liturgical service. I don't really understand why all these seperate Churches would have all this in common if the early Church didn't have it in common. He didn't specify why asking Saints to pray for us was bad but Christians were doing this before there was a Bible.