Final answer:
The difference between bilateral and unilateral descent lies in how kinship is traced. Bilateral descent considers both mother's and father's ancestors equally, whereas unilateral descent follows only one side, either patrilineal or matrilineal. Ambilineal allows a choice between the two depending on the situation.
Step-by-step explanation:
In kinship terms, there are two main systems of descent: bilateral and unilateral. Bilateral descent traces an individual's family through both parents, recognizing the contributions of both mother's and father's ancestors. In contrast, unilateral descent traces the lineage through only one side of the family. This can be either patrilineal, where descent is traced through the father's line, or matrilineal, where it's traced through the mother's line. A third type, called ambilineal descent, allows the choice of tracing descent through either the father or the mother, depending on specific circumstances.
In patrilineal descent, both male and female members carry the surname and are considered part of their father's lineage, but only males typically pass on the family name to their children. This system is commonly seen in societies like rural China and India. On the other hand, in matrilineal descent, lineage is carried and passed down through female members. This system emphasizes the mother's side of the family. Using my kinship association as an example, if my family surname follows my father's side and we adhere to that tradition, then it would be a patrilineal descent. However, if both my mother's and father's family names and heritage are recognized equally, then it would be bilateral descent.