Turkana Boy: Wikis

  
  

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Turkana Boy
Turkana Boy
Catalog number KNM-WT 15000
Common name Turkana Boy
Species Homo erectus or Homo ergaster
Age 1.6 mya
Place discovered Lake Turkana, Kenya
Date discovered 1984
Discovered by Kamoya Kimeu/Richard Leakey

Turkana Boy or Nariokotome Boy is the designation given to fossil KNM-WT 15000,[1] a nearly complete skeleton of a roughly 13-year-old[2][nb 1] hominid boy who died 1.5 million[3] years ago in the early Pleistocene. The skeleton was discovered in 1984 by Kamoya Kimeu, a member of a team led by Richard Leakey, at Nariokotome near Lake Turkana in Kenya.

Contents

Adolescence and maturity

Turkana Boy is classified as either Homo erectus or Homo ergaster. The shape of the pelvis indicates that it was a male. The aging of the skeleton is a contentious issue with different methods giving different ages. Anthropologists Alan Walker and Richard Leakey in 1993 estimated the boy to have been about 11-12 years old based known rates of bone maturity).[4][nb 2] Christopher Dean of University College, London in a Nova special claimed Turkana Boy was 8 years old at death.[5][6] Alan Walker and Richard Leakey, though, explain that dental dating often gives younger than actual ages.[7][nb 3]

Morphology

The skeleton was about 1.60 m (5 ft 3 in) tall, although he might have been 68 kg (150 lb) and 1.85 m (6 ft 1 in) tall had he lived to adulthood. The total skeleton is made up of 108 bones. The cranial capacity of Turkana Boy was about 880 cc, although, if he had lived to adulthood, it would have been about 910 cc, which is considerably smaller than the 1350 cc cranial capacity of modern humans, but does cross the bottom of the modern human range.

There are several features which seem awkward in comparison to modern humans. The pelvic structure is narrower than in modern Homo sapiens, meaning that Homo ergaster and Homo erectus in both Africa and Asia had a greater ability to run.[citation needed] Their running techniques may have been equivalent to a modern day race track athlete.[citation needed] This hints that the species lived a harsh and demanding lifestyle; most importantly they must have been accomplished hunters rather than scavengers such as Homo habilis. Radical changes are believed to have taken place during the transformation between the australopithecines and Homo species. Because of Homo ergaster's greater height and limb proportions, which are more similar to Homo sapiens than to the ape-like australopithecines, a combination of height and the thinning of body hair would have been a necessity.[citation needed] As such it has been speculated that the fine body hair now commonly found in humans would have been a necessity for the body's thermoregulatory mechanisms to maintain comfort during diurnal activities, thus facilitating the aerodynamics of bipedal movement.

Most importantly, the disparate thinning of body hair has been theorized as necessary in the shift towards savannah living and eventual encephalization, as postulated by P.E. Wheeler in The evolution of bipedality and Loss of Body hair in Hominids.

It can be speculated that much like their primate "relatives", the gorillas, Homo ergaster conserved its darker skin. A possible reason for this could be thermoregulation, although another school of thought postulates sexual selection, due to favouring a skin tone which would be easier to groom for parasites. In equatorial Africa, modern humans evolved this trait an estimated one million years ago.[citation needed] The loss of thick fur enabled the sweating mechanism to cool the body down to the required 37 °C. For any of these reasons, melanin development would have become crucial to surviving in open land under such conditions. This coloring of the skin is still present in equatorial populations of modern Homo sapiens.[citation needed].

The overall body stature, weight, and proportions coincidentally are somewhat similar to today's ethnic Maasai peoples living in modern day Kenya, with Bergman's rule and convergent evolution as possible explanations.

The overall KNM-WT 15000 skeleton still had features (such as a low sloping forehead, strong brow ridges, and the absence of a chin) not seen in present day modern humans.[citation needed] The arms of the species were slightly longer than seen in modern-day humans. It is currently believed that Turkana Boy had a projecting nose rather than the open flat nose-structure seen in apes and possibly acquired in australopithecines. The larger protruding nose helped to keep in moisture at a balanced temperature, cooling the blood in hot arid areas. The opposite could be said for Homo neanderthalensis (Neanderthals), who had unusually large nostrils which would warm and humidify cold and dry air before it reached the throat and lungs.

Social behavior & language

The fossil skeleton and other fossil evidence such as Acheulean stone tools prompts the majority of scientists to conclude that Homo ergaster and Homo erectus, unlike their more primitive ancestors, became efficient hunters. The social structure would probably have become more complex with a larger brain volume; the Broca's area of the brain allows speech and is noted by a slight slant on the cranium. Some anthropologists believe that simplistic sounds led to modern language. However, there are contradictory views on the notion of language. It remains controversial when modern human sounds and basic verbs first became used. The various possibilities include:

  • 1.9 million years ago (Homo habilis had a large Broca's area able to be seen in the cranium of KNM ER 1813), possible signs of the earliest ability for speech.
  • 1.5 million years ago, on the arrival of several distinct more human-like hominins spread throughout Africa, Europe, and Asia (i.e., Homo erectus).
  • 600,000 and 150,000 years ago when archaic Homo sapiens dominated regions in the Pleistocene epoch (several members during this period are considered fully modern Homo sapiens)[citation needed]
  • 50,000 years ago (fully modern Homo sapiens had already spread through the Old World and slowly into the New World 20,000 BCE). Some believe language coincided solely with modern humans once culture was established by groups such as Cro-Magnon man in Europe. It is still a matter of debate whether Neanderthals had a modern form of language.

Richard Leakey also mentions in his book Origin of humankind (1995) that Turkana Boy's thoracic vertebrae is narrower than in modern Homo sapiens's, meaning that he could not make complex speech due to less air being received into his lungs.

See also

References

  • Leakey, Richard (1994). The Origin of Humankind. ISBN 0-465-03135-8. 
  • Leakey, Richard. Origins Reconsidered. ISBN 0385412649. http://books.google.com/books?id=rGo8AAAACAAJ&dq=origins+reconsidered&ei=gY_QSJmpPIPWtgOD8eTbAw. 
  • Barraclough, G. (1989). Stone, N. (ed.). ed. Atlas of World History (3rd edition ed.). Times Books Limited. ISBN 0-7230-0304-1. 
  • Walker, Alan; Shipman, Pat. Wisdom of the Bones. ISBN 0-679-74783-4.  - Good popular level presentation
  • Alan Walker and Richard Leakey (eds.), ed. Nariokotome Homo Erectus Skeleton. ISBN 0-674-60075-4.  - Technical papers
  • Mckie, Robin (2000). Dawn of Man. BBC. ISBN 0-7894-6262-1. 
  • Wheeler, P.E. (1984). The Evolution of Bipedality and Loss of Functional Body Hair in Hominids t 13, 91-98. Journal of Human Evolution. ISBN 0047-2482-84-01009-1. 
  • Lewin, Roger (2004). Human Evolution: An Illustrated Introduction 5th Edition. Wiley. ISBN 978-1-4051-0378-7. 

Notes

  1. ^ "Thus, in all, 13 or 13.5 years seems to be a good compromise estimate of skeletal age in this individual using a modern human schedule."(Christopher-Dean, 2009, p. 104) Please note this is as of 2009
  2. ^ Walker in arriving at the figure explains:"in KNM-WT 15000, his skeletal development can only be used to place an upper limit of about 14 years on his age at death. However, a less often recognized skeletal maturational event does generally occur prior to 14 years in modern males-- the union of the trochlea and capitulum (and also the lateral epicondyle) of the humerus, prior to their joint union with the humeral shaft...That these elements were fused in KNM-WT 15000 (at least the capitulum and trochlea) suggests a skeletal age for him of somewhat more than 11 years...In either event, 11 to 12 years would seem to be the best compromise figure to use for his chronological age at death."(Walker & Leakey, 1993, p. 235)
  3. ^ "Just as in the case of human dental age (above), estimates based on tooth formation give slightly younger ages than those based on emergence."(Walker & Leakey, 1993, p. 207)

Footnotes

External links








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