Final answer:
The term for descendants in a direct line from one ancestor forming a group is lineage, a concept important in understanding family kinship and tracing ancestry in different societies.
Step-by-step explanation:
The descendants in a direct line from one ancestor form a lineage. This is a group of people related by a common ancestor through either the maternal or paternal line. Within communities, there may consist of multiple lineage groups, each led by elders who hold informal authority. These elders play a crucial role by using their knowledge and persuasion skills to establish consensus and resolve disputes within the group. Lineage is a crucial aspect of kinship, determining how individuals trace their ancestors and kin.
When tracing one's kinship, there are two systems - unilineal descent and bilateral descent. Unilineal descent involves tracing kinship through a single gendered line, which could be either the male (patrilineal) or female (matrilineal) line. Bilateral descent, on the other hand, traces ancestry through both the mother's and father's lines, as commonly found in North American and European societies. This kinship reckoning shapes social structures, obligations, and inheritance patterns within cultures.