Kinship is a relationship between any entities that share a genealogical origin, through either biological, cultural, or historical escent. In anthropology the kinship system includes people related both by descent and marriage, while usage in biology includes descent and mating. Human kinship relations through marriage are commonly called "affinity" in contrast to "descent" (also called "consanguinity"), although the two may overlap in marriages among those of common descent. Family relations as sociocultural genealogy lead back to gods (see mythology, religion), animals that were in the area or natural phenomena (as in origin stories).