A family tree is a chart representing family relationships in a conventional tree structure.
Family trees are usually presented with the oldest generation at the top and the newer generations below showing all the descendants of an individual. This is what we call a descendant family tree.
An ancestry family tree, on the other hand, presents an indivual at the top and all his ancestors below. This is what we call an ascendant family tree.
Look at the Simpson's family tree, can you tell which is an ascendant and a descedant tree?