The most important group is the family.

Nuclear: two adults and their children

Extended nuclear: grandparents / aunts uncles may live close by but in separate accommodation

Extended. All members share the same accommodation in which a hierarchy of authority (usually) with the older / providers having greatest authority.

Families, clans and tribes represent increasing groupings who provide or help one another’s members. This provides identity and requires obligations.

Genes are perpetuated within a tribe or larger social group, and values (culture - maps for understanding) are concentrated. Many of the determinants of social groupings have an economic, or by one step removed, political origin to do with control of access to resources and reproduction.