Homo sapiens

***Homo sapiens*** is the modern human species. *Homo sapiens* is a name in binomial nomenclature. It means that modern humans belong to the genus *Homo* and the species *sapiens*. It is abbreviated *H. sapiens*.

Modern humans are the only living species of the genus *Homo*. There were other species in this genus (like *Homo habilis* and *Homo erectus*), but they are extinct.

*Homo sapiens* are sometimes called "anatomically modern humans".

## Origin
Most scholars agree that modern humans originated in East Africa. This is the near-consensus position held within the scientific community.

The hypothesis that humans have a single origin was published in Charles Darwin's *The Descent of Man* (1871). Modern studies of mitochondrial DNA support this theory. So does evidence based on physical anthropology of fossil humans. 

According to genetic and fossil evidence, older versions of *H. sapiens* evolved only in Africa, between 200,000 and 100,000 years ago. Then members of one branch of *H. sapiens* left Africa by 90,000 years ago. Over time, it replaced earlier human populations such as Neanderthals and *Homo erectus*.

### Neanderthal genome 
Sequencing of the full Neanderthal genome suggests Neanderthals and some modern humans share some ancient genetic lineages. Some populations may have as much as 4% Neanderthal DNA, according to the authors of this study. The reason for this admixture is not known. 

This DNA overlap may exist because both Neanderthals and modern humans had a common ancestor, according to an August 2012 study.

## Evolution
The genus *Homo* evolved out of the last common ancestor roughly 10 to 2 million years ago. The species *H. sapiens* evolved from *Homo erectus* roughly 1.8 to 0.2 million years ago.

Scientific study of human evolution focuses mostly on how the genus *Homo* developed. However, it usually involves studying other hominids and hominines as well, such as *Australopithecus*. 

### Extinct subspecies 
Within the *Homo sapiens* species, modern humans belong to the only living subspecies: *Homo sapiens sapiens*. *Homo sapiens idaltu*, the other known subspecies, is now extinct. 

*Homo neanderthalensis*, which became extinct 30,000 years ago, has sometimes been classified as a subspecies, "*Homo sapiens neanderthalensis*". Genetic studies now suggest that the functional DNA of modern humans and Neanderthals diverged 500,000 years ago.

Similarly, some scientists have classified the discovered specimens of the *Homo rhodesiensis* species as a subspecies, but this classification is not widely accepted.

### Earliest fossils of the species
Until recently it was thought that anatomically modern humans first appeared in the fossil record in Africa about 195,000 years ago. However, studies of molecular biology suggest that 200,000 years ago, modern humans diverged from the common ancestor of all human populations. 

A broad study of African genetic diversity found the ǂKhomani San people had the greatest genetic diversity among the 113 distinct populations sampled. This makes them one of 14 "ancestral population clusters". The research also placed the origin of modern human migration in south-western Africa, near the coastal border of Namibia and Angola.

In the 1960s an archaeological site at Jebel Irhoud in Morocco was dated as about 40,000 years old. However, it was re-dated in the 2000s. It is now thought to be between 300,000 and 350,000 years old. The skull form is almost identical to modern humans, though the jaw is different.

The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome show selection in the past 15,000 years.

## Related pages 
* Evolution
* Natural selection
* Binomial nomenclature
* *Homo*
* Neanderthal genome project

## References