Out of Africa theory

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As the Out-of-Africa-Theory (also: Out-of-Africa-Hypothesis ) is called in the paleoanthropology the theory that the genus Homo had its origin in Africa (" cradle of mankind ") and that their relatives came from there spread all over the world. The name Out of Africa was created in the mid-1980s. It was represented as a hypothesis as early as 1871 by Charles Darwin in his work The Descent of Man and Sexual Selection and was repeatedly taken up by later authors. A well-known example is Robert Ardrey : His book African Genesis was published in 1961, the German version Adam came from Africa in 1967. The theory was later presented by Günter Bräuer at the 1st International Congress for Paleoanthropology in Nice in 1982 with a view to anatomically modern humans ( Homo sapiens ) as the "Afro-European Sapiens Hypothesis". Today in the specialist literature, two migrations that are independent of one another in terms of time and space are occasionally summarized under the Out-of-Africa theory .

Out-of-Africa I

A migration , which is included under the out-of-Africa theory , refers to the emergence and spread of Homo erectus , whose oldest known fossils outside Africa - the Dmanissi finds - are around 1.8 million years old (also : "Out-of-Africa I").

The discovery of the 1.8 million year old fossils from Dmanissi and the Flores fossils and their preliminary derivation from Homo erectus has revived a debate in professional circles about whether Australopithecus- like populations have already left Africa, evolved outside Africa to Homo erectus and this then also repopulated Africa.

Even older than the Dmanissi finds are 2.1 million years old stone tools , which were discovered in the district of Lantian ( Shaanxi Province , People's Republic of China ) in the Shangchen site , but which, due to the lack of fossils, could not be assigned to a specific type of hominini. The Shangchen- finds are the datings According significantly older than - those with an age of 1.9 million years ago - the earliest fossils of Homo erectus / ergaster in Africa.

Out-of-Africa II

The migration of Homo sapiens across the Middle East to Australia .
M 168 and M 130 denote markers in the Y chromosome of humans (cf. Adam of the Y chromosome ).
The colonization of Eurasia by Homo sapiens from around 40,000 years ago. M denotes markers on the Y chromosome in humans.

The term Out-of-Africa was initially only applied to the spread of anatomically modern humans ( Homo sapiens ) (today also: "Out-of-Africa II" or Recent African Origin ); Evidence for this is for example the fossils Omo 1 and Omo 2 as well as the Herto skull from Ethiopia , which are among the oldest known records of Homo sapiens .

Basically, two possible migration routes are discussed. On the one hand, it is assumed that when the sea level was low (e.g. during an ice age) the strait between the Horn of Africa and the Arabian Peninsula near Bab al-Mandab was only half as wide as it is today, making it easier to cross. If people stayed near the coast after that, they came to Asia along the Indian Ocean . A second possible route is to hike northwards along the Nile, which often formed a “green lane” through the Sahara.

One consequence of Bräuer's argument, initially called the “Afro-European Sapiens Hypothesis”, was the assumption that Homo sapiens - coming from Africa - replaced the Neanderthals in Europe and other archaic species such as Homo erectus in Asia (“replacement” instead of “continuity”) .

With regard to Homo sapiens, the Out-of-Africa theory is not only supported by numerous fossil finds, but also by genetic (see also the two graphics) and linguistic findings. It is the theory of the origin of humans that is advocated by the majority of researchers today and, since the mid-1980s, has formed the opposite pole to the hypothesis of the multiregional origin of modern humans , which was refuted by genetic analyzes . This hypothesis was based on the assumption that Homo sapiens developed in Africa, Europe, Australia and Asia - separately from one another - from a common ancestor of the genus Homo .

Genetic studies on tapeworms of the genus Taenia provide additional, independent evidence for the origin of Homo sapiens from Africa , which suggest that early representatives of the genus Homo had close contact with African predators and scavengers, at least indirectly . The species Taenia saginata and Taenia asiatica , which also occur in humans, are closely related to a tapeworm found in African lions , and Taenia solium is closely related to a tapeworm in hyenas . If it was initially assumed that these tapeworms had passed from cattle and pigs to humans with the advent of cattle breeding around 10,000 years ago, the genetic studies were interpreted to mean that the transition probably already took place 1.7 million years ago in Homo ergaster .

If, as some researchers assume today, the individuals classified as Homo heidelbergensis in Europe more than 600,000 years ago separated from Homo erectus and thus from the line of development leading to Homo sapiens and - coming from Africa - settled in Europe, would be attributed to Homo heidelbergensis “Out-of-Africa II” and the later spread of Homo sapiens “Out-of-Africa III”.

See also

literature

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Individual evidence

  1. ↑ Chris Stringer : The Origin of Our Species. Penguin / Allen Lane, 2011, ISBN 978-1846141409 , p. 77.
  2. ^ Charles Darwin: The Descent of Man , Volume 1, Chapter 6, p. 199 .
  3. ^ Günter Bräuer: Early anatomically modern man in Africa and the replacement of the Mediterranean and European Neanderthals. I. Congrès International de Paléontologie Humaine. Nice 1982, Resumés: 112.
  4. ^ John G. Fleagle et al .: Out of Africa I: The First Hominin Colonization of Eurasia. Springer, 2010, ISBN 9048190355 .
  5. ↑ “The narrative of human evolution […] is known as 'Out of Africa 1'. This postulates that the genus Homo originated in Africa, and as H. ergaster or H. erectus , left Africa about 1.8 million years ago. " In: Walking with humans. - Nature of December 22, 2005, doi: 10.1038 / nature04259 .
  6. ↑ Carl C. Swisher 3rd, Garniss Curtis , Teuku Jacob et al .: Age of the earliest known hominids in Java, Indonesia. In: Science. Volume 263, No. 5150, 1994, pp. 1118-1121, doi: 10.1126 / science.8108729 .
  7. ↑ Bernard Wood : Did early Homo migrate “out of” or “in to” Africa? In: PNAS. Volume 108, No. 26, 2011, pp. 10375-10376, doi: 10.1073 / pnas.1107724108 .
    Colin Barras: Our Asian Origin. In: New Scientist . Volume 218, No. 2916, 2013, pp. 40-43.
  8. ↑ Zhaoyu Zhu, Robin Dennell , Weiwen Huang et al .: Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago. In: Nature. Volume 559, 2018, pp. 608-612, doi: 10.1038 / s41586-018-0299-4 .
    Our ancestors may have left Africa hundreds of thousands of years earlier than thought. On: sciencemag.org of July 11, 2018.
    An early hominin arrival in Asia. On: nature.com from July 11, 2018
  9. ^ Allan C. Wilson and Rebecca L. Cann : The Recent African Genesis of Humans. In: Scientific American. Volume 266, 1992, pp. 68-73.
  10. ^ Günter Bräuer: The "Afro-European sapiens hypothesis" and hominid evolution in East Asia during the late Middle and Upper Pleistocene. In: Courier Research Institute Senckenberg. Volume 69, 1984, pp. 145-165.
  11. ↑ Rebecca L. Cann, Mark Stoneking and Allan C. Wilson: Mitochondrial DNA and human evolution. In: Nature. Volume 325, 1987, pp. 31-36, doi: 10.1038 / 325031a0 .
  12. ↑ Quentin D. Atkinson: Phonemic Diversity Supports a Serial Founder Effect Model of Language Expansion from Africa. In: Science. Volume 332, No. 6027, 2011, pp. 346-349, doi : 10.1126 / science.1199295 .
  13. ↑ Chris Stringer: Human evolution: Out of Ethiopia. In: Nature. Volume 423, 2003, pp. 692-695, doi: 10.1038 / 423692a .
  14. ↑ Michael D. Petraglia et al .: Out of Africa: new hypotheses and evidence for the dispersal of Homo sapiens along the Indian Ocean rim. In: Annals of Human Biology. Volume 37, No. 3, 2010, pp. 288-311, doi: 10.3109 / 03014461003639249 .
  15. ↑ Hugo Reyes-Centeno, Silvia Ghirotto, Florent Détroit, Dominique Grimaud-Hervé, Guido Barbujani and Katerina Harvati : Genomic and cranial phenotype data support multiple modern human dispersals from Africa and a southern route into Asia. In: PNAS . Volume 111, No. 20, 2014, pp. 7248-7253, doi: 10.1073 / pnas.1323666111 .
  16. ↑ Tapeworms tell tales of deeper human past. In: Science News of July 1, 2009, doi: 10.2307 / 3981638
  17. ^ EP Hoberg, NL Alkire, AD Queiroz and A. Jones: Out of Africa: origins of the Taenia tapeworms in humans. In: Proceedings of the Royal Society B. Online publication of April 22, 2001, doi: 10.1098 / rspb.2000.1579 .
  18. ↑ Michael Balter: In Search of the First Europeans. In: Science . Volume 291, No. 5509, 2001, pp. 1722-1725, doi : 10.1126 / science.291.5509.1722 .
  19. ↑ Thomas Junker : The evolution of man. 2nd Edition. CH Beck, Munich 2008, pp. 38-40. - Junker uses Arabic numerals.