ancestor          
noun [ C ] uk/ˈæn.ses.tər/ us/ˈæn.ses.tɚ/
B2 祖先,祖宗
a person related to you who lived a long time ago
  There were portraits of his ancestors on the walls of the room. 房间墙壁上挂着他祖先的画像。 
 Compare: descendant
  (动植物)原种;(物体)原型
a plant, animal, or object that is related to one existing at a later point in time
  This wooden instrument is the ancestor of the modern metal flute. 这种木质乐器是现代金属长笛的雏形。 
 - More examples
 - Twelve thousand years ago, our ancestors were primitive savages living in caves.
 - Apparently his ancestors came over from France in the 11th century.
 - She claims that Mary Queen of Scots is one of her distant ancestors.
 - These bones come from an animal that is the ancestor of the modern horse.
 - Archaeology can tell us a lot about how our Iron-Age ancestors lived.