In biological classification, a "genus" is a rank used to group species that are closely related and share a common ancestor. It is one level above species and one level below family in the hierarchical system known as taxonomy. For example, the genus Homo includes species like Homo sapiens (modern humans) and Homo neanderthalensis (Neanderthals). Each genus contains one or more species, and the name of the genus is always capitalized and italicized. This classification helps scientists communicate more effectively about different organisms. For instance, the genus Canis includes species such as Canis lupus (wolves) and Canis familiaris (domestic dogs).