Mythos 4 – Homo Erectus

 

The other modern-hominin at the beginning of the Pleistocene was the Homo ergaster, also called African Homo erectus.(1)Manji Hazarika (2007) “Homo erectus/ergaster and Out of Africa: Recent Developments in Paleoanthropology and Prehistoric Archaeology” Universitat Rovira i Virgili Homo ergaster lived in eastern and southern Africa during the early Pleistocene, between 1.8 million and 1.3 million years ago. There is still disagreement on the subject of the classification, ancestry, and descendants of Homo ergaster. The current consensus among palaeo-anthropologists is to consider Homo ergaster to be simply the African variety of Homo erectus.(2)S. C. Antón (2003) “Natural history of Homo erectus” American Journal of Physical Anthropology Volume 122, Pages 126–170 Until the fossil discoveries of the past few decades, Homo erectus were believed to have appeared on the planet early in the Pleistocene, and the have existed until they became extinct around 143,000 years ago. The discoveries in Dmanisi, Georgia, since 1991 have made palaeo-anthropologists reconsider previous concepts. The older hypothesis was that Homo erectus migrated from Africa during the Early Pleistocene, and dispersed throughout much of Eurasia. The second hypothesis is that Homo erectus evolved in Eurasia and then migrated to Africa. The species occupied a site in Dmanisi, Georgia, from 1.85 million to 1.77 million years ago, slightly before the earliest evidence in Africa. Excavations found 73 stone tools for cutting and chopping and 34 bone fragments from unidentified creatures.(3)R. Ferring et al. (2011) “Earliest human occupations at Dmanisi (Georgian Caucasus) dated to 1.85-1.78 Ma” Proceedings of the National Academy of Sciences Volume 108, Number 26, Page 10432 Other fossilized remains from 1.8 to 1 million years old have been found in Kenya,(4)Kendrick Frazier (2006) “Leakey Fights Church Campaign to Downgrade Kenya Museum’s Human Fossils” Skeptical Inquirer magazine Volume 30, Page 6 Tanzania, Indonesia, Vietnam, China, and India.(5)Harald E. L. Prins et al. (2007) Evolution and prehistory: the human challenge, Page 162

Artist's Impression of Homo Erectus' on the African Savannah

Artist’s Impression of Homo Erectus’ on the African Savannah

A new debate appeared in 2013 in the palaeontological community, with the publication of the Dmanisi skull 5 also called D4500.(6)Sid Perkins (2013-10-17) “Skull suggests three early human species were one” Nature Considering the large morphological variation between all Dmanisi skulls, researchers suggests that many species of early human ancestor such as Homo ergaster or Homo heidelbergensis and even Homo habilis were actually all Homo erectus.(7)David Lordkipanidze et al. (2013) “A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo” Science, Volume 342, Number 6156, Pages 326–331 The variation in morphology of all the Dmanisi skulls are so large that had they been discovered on different archaeological sites, they most likely would have been classified as different species. However, all Dmanisi skulls have the same age and have been found at exactly the same place. Faced with the wide variation between Skull 5 and the others Dmanisi skulls, Georgian and Swiss researchers were prompted to examine normal variations in modern human skulls and chimpanzees skulls. They found that while they looked different from one another, the great variations between all Dmanisi skulls were no greater than those seen among modern humans, or among chimpanzees. Consequently, it was entirely possible that such variations could be found in Homo erectus. The unification of these species is an ongoing debate among the scientific community.(8)Brian Switek (October 19, 2013) “Beautiful Skull Spurs Debate on Human History” National Geographic

The Five Dmanisi Skulls

The Five Dmanisi Skulls

Prior to the expansion of the Homo erectus family, the cranial capacity was believed to be 850cm³ to 1,100cm³. With the various additions made in the past few years the expanded Homo erectus estimate would need to be 510cm³ to 1,400 cm³. This implies that some of these tool making, fire using people had cranial capacities smaller than some apes. One possible explanation is that archaic-humans showed greater sexual dimorphism; the females had much smaller skulls, as they do in the great ape species.(9)C. Lorenzo et al. (May 1998) “Intrapopulational body size variation and cranial capacity variation in Middle Pleistocene humans: the Sima de los Huesos sample (Sierra de Atapuerca, Spain)” US National Library of Medicine National Institutes of Health If the expanded Homo erectus theory holds up, then the species would have existed from 2.2 million to 125,000 years ago.

Since only one of the skulls at Dmanisi (Skull 5) was significantly smaller than the rest, it is equally possible that the larger Homo erectus people were keeping a smaller Homo Habilis as a pet, or even a food source. If so then the Homo habilis line could continue to be treated as an independent species, or moved into the Australopithecus as suggested in the Journal of Anatomy in 2000.(10)Barnard Wood and Brian G. Richmond (2000) “Human evolution: taxonomy and paleobiology” Journal of Anatomy, Volume 197, Part 1, Number 19–60, Page 41 This would mean that Homo erectus (H. ergaster, H. heidelbergensis, H. rhodesiensis, H. rudolfensis) would be left with an estimated cranial capacity of 700cm³ to 1,400cm³, far closer to the established variance pattern found within Humans (950cm³ to 1,800cm³) and Neanderthals (1,200cm³ to 1,900cm³). Regardless of how big the Homo erectus family was, human evolution theoretically continues with modern-Humans evolving out of Homo erectus (Homo rhodesiensis) in Africa,(11)Renée Hetherington and Robert G. B. Reid (2010) “The Climate Connection Climate Change and Modern Human Evolution” Page 64 while Neanderthals and Desovians evolved from Homo erectus (Homo heidelbergensis) in Eurasia.(12)Dmitra Papagianni and Michael Morse (2013) The Neandethals Rediscovered

References   [ + ]

1. Manji Hazarika (2007) “Homo erectus/ergaster and Out of Africa: Recent Developments in Paleoanthropology and Prehistoric Archaeology” Universitat Rovira i Virgili
2. S. C. Antón (2003) “Natural history of Homo erectus” American Journal of Physical Anthropology Volume 122, Pages 126–170
3. R. Ferring et al. (2011) “Earliest human occupations at Dmanisi (Georgian Caucasus) dated to 1.85-1.78 Ma” Proceedings of the National Academy of Sciences Volume 108, Number 26, Page 10432
4. Kendrick Frazier (2006) “Leakey Fights Church Campaign to Downgrade Kenya Museum’s Human Fossils” Skeptical Inquirer magazine Volume 30, Page 6
5. Harald E. L. Prins et al. (2007) Evolution and prehistory: the human challenge, Page 162
6. Sid Perkins (2013-10-17) “Skull suggests three early human species were one” Nature
7. David Lordkipanidze et al. (2013) “A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo” Science, Volume 342, Number 6156, Pages 326–331
8. Brian Switek (October 19, 2013) “Beautiful Skull Spurs Debate on Human History” National Geographic
9. C. Lorenzo et al. (May 1998) “Intrapopulational body size variation and cranial capacity variation in Middle Pleistocene humans: the Sima de los Huesos sample (Sierra de Atapuerca, Spain)” US National Library of Medicine National Institutes of Health
10. Barnard Wood and Brian G. Richmond (2000) “Human evolution: taxonomy and paleobiology” Journal of Anatomy, Volume 197, Part 1, Number 19–60, Page 41
11. Renée Hetherington and Robert G. B. Reid (2010) “The Climate Connection Climate Change and Modern Human Evolution” Page 64
12. Dmitra Papagianni and Michael Morse (2013) The Neandethals Rediscovered