When a family historian, for example, traces their family, they can use either a pedigree sheet (often called a pedigree chart) or a family tree (or family group sheet). The pedigree sheet provides less information than the family tree.
In a pedigree chart, only the direct ancestors of the person of interest are listed. In other words, my pedigree sheet would include my mother and her parents. But it would not include my mother's siblings or her parents' siblings. This is because those people are not my direct ancestors.
By contrast, a family tree would show all of those people who are omitted from the pedigree chart. It would show my aunts and uncles and cousins and my great aunts and uncles as well.
A family tree, therefore, gives much more information than a pedigree sheet does.
A Pedigree Sheet traces back the direct family lines from parents to grand parents and beyound whereas a Family Tree will show all descendents of common ancestors.