Homo sapiens

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Homo sapiens
Temporal range: 0.3–0 Ma
Middle PleistocenePresent
Akha man and woman in northern Thailand – husband carries stem of banana-plant, which will be fed to their pigs
Male and female H s. sapiens
(Akha in northern Thailand,
2010 photograph)
Conservation status
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Family: Hominidae
Genus: Homo
Species: H. sapiens
Binomial name
Homo sapiens
Linnaeus, 1758
Subspecies

H. s. sapiens
H. s. idaltu
H. s. neanderthalensis(?)
H. s. rhodesiensis(?)
(others proposed)

Homo sapiens (Latin: "wise man") is the scientific name for the human species.

Homo is the human genus, which also includes Neanderthals and many other extinct species of hominid. H. sapiens is the only surviving species of the genus Homo.

Modern humans are sometimes called "anatomically modern humans". Homo sapiens considers itself the most influential species on the planet. However, many kinds of life, especially plants and protists, have had a much greater effect on the air, the rocks, life, and natural environment on Earth.

Origin[change | change source]

Schematic representation of the emergence of H. sapiens from earlier species of Homo. The horizontal axis shows geographic location; the vertical axis shows time in millions of years ago.
Blue areas show presence at a given time and place.[2]

The recent African origin of modern humans is the mainstream model of the origin and dispersal of anatomically modern humans.[3]

The hypothesis that humans have a single origin was published in Charles Darwin's The Descent of Man (1871). The concept is supported by a study of present-day mitochondrial DNA, and with evidence based on physical anthropology of fossil humans. According to genetic and fossil evidence, older versions of Homo sapiens evolved only in Africa, between 200,000 and 100,000 years ago, with members of one branch leaving Africa by 90,000 years ago and over time replacing earlier human populations such as Neanderthals and Homo erectus.

The recent single origin of modern humans in East Africa is the near-consensus position held within the scientific community.[4][5][6][7][8]

Sequencing of the full Neanderthal genome suggests Neanderthals and some modern humans share some ancient genetic lineages. The authors of the study suggest that their findings are consistent with Neanderthal admixture of up to 4% in some populations. The reason for this admixture is not known.[9] In August 2012, a study suggested that the DNA overlap is a remnant of a common ancestor of both Neanderthals and modern humans.[10][11]

Evolution[change | change source]

Further information: Human evolution

The time frame for the evolution of the genus Homo out of the last common ancestor is roughly 10 to 2 million years ago, that of H. sapiens out of Homo erectus roughly 1.8 to 0.2 million years ago.

Scientific study of human evolution is mostly concerned with the development of the genus Homo, but usually involves studying other hominids and hominines as well, such as Australopithecus. "Modern humans" are defined as the Homo sapiens species, of which the only living subspecies is known as Homo sapiens sapiens.

Homo sapiens idaltu, the other known subspecies, is now extinct.[12] 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.[13]

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

Earliest fossils of our species[change | change source]

Until recently it was thought that anatomically modern humans first appeared in the fossil record in Africa about 195,000 years ago. Studies of molecular biology suggested that the approximate time of divergence from the common ancestor of all modern human populations was 200,000 years ago.[14][15][16][17][18] The broad study of African genetic diversity found the ǂKhomani San people had the greatest genetic diversity among the 113 distinct populations sampled, making 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.[19][20]

In the 1960s an archaeological site at Jebel Irhoud in Morocco was dated as about 40,000 years old but 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,[21] 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.[22]

References[change | change source]

  1. Global Mammal Assessment Team (2008). "Homo sapiens". The IUCN Red List of Threatened Species (IUCN) 2008: e.T136584A4313662. doi:10.2305/IUCN.UK.2008.RLTS.T136584A4313662.en. http://www.iucnredlist.org/details/136584/0. Retrieved 12 January 2018. 
  2. Stringer, C. (2012). "What makes a modern human". Nature 485 (7396): 33–35. doi:10.1038/485033a. PMID 22552077. 
  3. Wood B. 2010. Reconstructing human evolution: achievements, challenges, and opportunities. Proceedings of the National Academy of Sciences 107: 8902–8909. [1]
  4. Hua Liu et al 2006. A geographically explicit genetic model of worldwide human-settlement history American Journal of Human Genetics 79, 230–237, quote: "Currently available genetic and archaeological evidence is generally interpreted as supportive of a recent single origin of modern humans in East Africa. However, this is where the near consensus on human settlement history ends, and considerable uncertainty clouds any more detailed aspect of human colonization history".
  5. "Out of Africa revisited - Science 308 (5724): 921g -". Sciencemag.org. 2005-05-13. doi:10.1126/science.308.5724.921g. Retrieved 2009-11-23. 
  6. Nature (2003-06-12). "Access: human evolution: out of Ethiopia". Nature. Retrieved 2009-11-23. 
  7. "Origins of modern humans: multiregional or out of Africa?". ActionBioscience. Retrieved 2009-11-23. 
  8. "Modern humans - single origin (out of Africa) vs multiregional". Asa3.org. Retrieved 2009-11-23. 
  9. Green R.E. et al (2010). "A draft sequence of the Neanderthal genome". Science (Science (journal)) 328 (5979): 710–22. doi:10.1126/science.1188021. PMID 20448178. http://www.sciencemag.org/cgi/content/full/328/5979/710. 
  10. Study casts doubt on human-Neanderthal interbreeding theory, The Guardian, Tuesday 14 August 2012
  11. Anders Eriksson and Andrea Manica Effect of ancient population structure on the degree of polymorphism shared between modern human populations and ancient hominins PNAS 2012 : 1200567109v1-201200567. July 20, 2012
  12. Human evolution: the fossil evidence in 3D, by Philip L. Walker and Edward H. Hagen, Dept. of Anthropology, University of California, Santa Barbara. Retrieved April 5, 2005.
  13. Green R.E.; et al. (2006). Analysis of one million base pairs of Neanderthal DNA. Nature. pp. 16, 330–336. 
  14. nsf.gov - National Science Foundation (NSF) News - New clues add 40,000 years to age of human species - US National Science Foundation (NSF)
  15. "Age of ancient humans reassessed". BBC News. February 16, 2005. Retrieved April 10, 2010. 
  16. The oldest Homo sapiens: – URL retrieved May 15, 2009
  17. Alemseged, Z., Coppens, Y., Geraads, D. (2002). "Hominid cranium from Homo: description and taxonomy of Homo-323-1976-896". Am J Phys Anthropol 117 (2): 103–12. doi:10.1002/ajpa.10032. PMID 11815945. 
  18. Stoneking, Mark; Soodyall, Himla (1996). "Human evolution and the mitochondrial genome". Current Opinion in Genetics & Development 6 (6): 731–6. doi:10.1016/S0959-437X(96)80028-1. 
  19. Henn, Brenna; Gignoux, Christopher R.; Jobin, Matthew (2011). "Hunter-gatherer genomic diversity suggests a southern African origin for modern humans". Proceedings of the National Academy of Sciences of the United States of America (National Academy of Sciences) 108 (13): 5154–62. doi:10.1073/pnas.1017511108. 
  20. Gill, Victoria (May 1, 2009). "Africa's genetic secrets unlocked". BBC News. ; the results were published in the online edition of the journal Science.
  21. Ghosh P. 2017. First of our kind found in Morocco. BBC News Science & Environment. [2]
  22. Wade, N (2006-03-07). "Still evolving, human genes tell new story". The New York Times. Retrieved 2008-07-10.