A pedigree is a tree diagram that represents the relationships between different individuals based on certain facts and medical(genetic evolutionary) histories. Basically , the branches of the tree represents the generations which allows the researcher understand how certain genetic characteristics or traits are transmitted with in a family
Such as transmission of any genetic diseases from one generation to the other.
The similarities between bones of humans and other animals shows that every living creature on earth has a common ancestor, even if that common ancestor is as simple as a sing-celled organism.