In a larger sense it can be thought of as the study of family ancestries and histories. Tracking the descent from an original family progenitor is sometimes desired, and can result in very large pedigrees. Lineage and ancestry provides many individuals and families with satisfying connections and links to their pasts. These have been represented by genealogical tree diagrams.
Diagrams of different kinds showing the relationships between people in several generations of a family are helpful to organize and convey large amounts of information. Genealogical data can be represented in several formats, for example as a pedigree or ancestry chart. Family trees are often presented with the oldest generations at the top and the newer generations at the bottom. An ancestry chart, which is a tree showing the ancestors of an individual, will more closely resemble a tree in shape, being wider at the top than the bottom.
In some ancestry charts, an individual appears on the left and his or her ancestors appear to the right. A descendancy chart, which depicts all the descendants of an individual will be narrowest at the top. Family trees can have many themes. One might encompass all direct descendants of a single figure, or all known ancestors of a living person. Another might include all members of a particular surname (e.g. male-line descent).