Name and taxonomy
The binomial name Homo sapiens was coined by Carl Linnaeus (1758). The Latin noun homō (genitive hominis) means "human being", while the participle sapiēns means "discerning, wise, sensible".
The species is taken to have emerged from a predecessor within the genus Homo around 300,000 to 200,000 years ago. A problem with the morphological classification of "anatomically modern" was that it would not have included certain extant populations. For this reason, a lineage-based (cladistic) definition of H. sapiens has been suggested, in which H. sapiens would by definition refer to the modern human lineage following the split from the Neanderthal lineage. Such a cladistic definition would extend the age of H. sapiens to upward of 500,000 years.
Extant human populations have historically been divided into subspecies, but since c. the 1980s all extant groups tend to be subsumed into a single species, H. sapiens, avoiding division into subspecies altogether.
Some sources show Neanderthals (Homo neanderthalensis) as a subspecies (Homo sapiens neanderthalensis). Similarly, the discovered specimens of the Homo rhodesiensis species have been classified by some as a subspecies (Homo sapiens rhodesiensis), although it remains more common to treat these last two as separate species within the genus Homo rather than as subspecies within H. sapiens.
The subspecies name Homo sapiens sapiens is sometimes used informally instead of "modern humans" or "anatomically modern humans". It has no formal authority associated with it. By the early 2000s, it becomes common to use H. s. sapiens of the ancestral population of all contemporary humans, and as such is equivalent to the binomial H. sapiens in the more restrictive sense (considering H. neanderthalensis a separate species).