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| map_caption = Olduvai Gorge in Tanzania
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'''Olduvai Gorge''', or '''Oldupai Gorge''', in [[Tanzania]] is one of the most important [[paleoanthropology|paleoanthropological]] sites in the world and has been instrumental in furthering the understanding of early [[human evolution]]. This site was occupied by ''[[Homo habilis]]'' approximately 1.9 million years ago, ''[[Paranthropus boisei]]'' 1.8 million years ago, and ''[[Homo erectus]]'' 1.2 million years ago. ''[[Homo sapiens]]'' is dated to have occupied the site 17,000 years ago. Olduvai Gorge is a steep-sided ravine in the [[Gregory Rift|Great Rift Valley]] that stretches through [[eastern Africa]]. It is in the eastern [[Serengeti Plains]] in [[Arusha Region]], [[Tanzania]] and is about {{convert|48|km|abbr=on}} long. It is located {{convert|45|km|abbr=on}} from the [[Laetoli]] archaeological site.
'''Olduvai Gorge''', or '''Oldupai Gorge''', in [[Tanzania]] is one of the most important [[paleoanthropology|paleoanthropological]] sites in the world; it has proven invaluable in furthering understanding of early [[human evolution]]. =\\=''[[Homo habilis]]'', probably the first early human species, occupied '''Olduvai Gorge''' approximately 1.9 million years ago (mya); then came a contemporary [[australopithecine]], ''[[Paranthropus boisei]]'', 1.8 mya, and then ''[[Homo erectus]]'', 1.2 mya. ''[[Homo sapiens]]'' is dated to have occupied the site 17,000 years ago. A steep-sided ravine in the [[Gregory Rift|Great Rift Valley]] that stretches across [[East Africa]], it is about {{convert|48|km|abbr=on}} long, and is located in the eastern [[Serengeti Plains]] in the [[Arusha Region]] not far, about 45 km, from [[Laetoli]], another important archaeological site of early human occupation. The British/Kenyan paleoanthropologist-archeologist team [[Mary Leakey|Mary and Louis Leakey]] established and developed the excavation and research programs at '''Olduvai Gorge''' which achieved great advances of human knowledge and world-renown status.


This site is significant in showing increased developmental and social complexities in [[hominids]]. Evidence of this is shown in the production and use of [[stone tools]], which indicates the increase in [[cognitive]] capacities. Evidence also indicates the practices of both [[Scavenger|scavenging]] and [[hunting]], which are highlighted by the evidence of gnaw marks predating cut marks, and comparisons on percentages of meat versus plant in the early hominid diet. Furthermore, the collection of tools and animal remains in a central area is evidence of increases in [[social interaction]] and communal activity.
The site is significant in showing the increasing developmental and social complexities in the earliest humans, or [[hominins]], largely as revealed in the production and use of [[stone tools]]. And prior to tools, the evidence of [[Scavenger|scavenging]] and [[hunting]]—highlighted by the presence of gnaw marks that predate cut marks—and of the ratio of meat versus plant material in the early hominin diet. The collecting of tools and animal remains in a central area is evidence of developing [[social interaction]] and communal activity. All these factors indicate increase in [[cognitive]] capacities at the beginning of the period of [[hominids]] transitioning to [[hominin]]—that is, to human—form and behavior.


==History==
==History==
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===Research===
===Research===
Researchers dated Olduvai Gorge using [[radiometric dating]] of the embedded [[artifact (archaeology)|artifact]]s, mostly through [[potassium-argon dating]] and [[argon–argon dating]]. German neurologist [[Wilhelm Kattwinkel]] traveled to Olduvai Gorge in 1911,<ref>Maier, Gerhard, ''African Dinosaurs Unearthed: The Tendaguru Expeditions,'' Indiana University Press, 2003, p. 116 ISBN 978-0253342140</ref> where he noticed many [[fossil]] bones of an extinct three-toed horse. Kattwinkel's discovery inspired Professor [[Hans Reck]] to lead a team to Olduvai Gorge in 1913. There, he found a [[hominid]] skeleton, but unfortunately the start of [[World War I]] halted his [[research]].
German neurologist [[Wilhelm Kattwinkel]] traveled to Olduvai Gorge in 1911,<ref>Maier, Gerhard, ''African Dinosaurs Unearthed: The Tendaguru Expeditions,'' Indiana University Press, 2003, p. 116 ISBN 978-0253342140</ref> where he observed many [[fossil]] bones of an extinct three-toed horse. Inspired by Kattwinkel's discovery, German geologist [[Hans Reck]] led a team to Olduvai in 1913. There, he found [[hominin]] remains, but the start of [[World War I]] halted his research. In 1929, [[Louis Leakey]] visited Reck and viewed the Olduvai fossils; he became convinced that Olduvai Gorge held critical information on human origins, and he proceeded to mount an expedition there.


In 1931, [[Louis Leakey]] found Olduvai fossils in [[Berlin]] and thought Olduvai Gorge held information on human origins, and thus began excavating there. Louis and [[Mary Leakey]] are the archaeologists responsible for most of the [[excavations]] and discoveries of the hominid fossils in Olduvai Gorge. Their finds, when added to the prior work of [[Raymond Dart]] and [[Robert Broom]], convinced most paleoanthropologists that humans originally evolved in [[Africa]]. At the Frida Leakey Korongo (FLK) site (named after Louis' first wife) in 1959, Mary found remains of the robust australopithecine ''[[Zinjanthropus boisei]]'' (now known as ''Paranthropus boisei''). The specimen's age of 1.75 million years radically altered the accepted ideas about the time scale of human [[evolution]]. They also found and studied more than 2,000 stone tools and flakes at the site, which were classified as Oldowan tools, in addition to an abundance of faunal remains. Louis Leakey's son Jonathan found the first specimen of ''[[Homo habilis]]'', a jaw fragment, at Olduvai in 1960.
Louis and [[Mary Leakey]] are responsible for most of the [[excavations]] and discoveries of the hominin fossils in Olduvai Gorge. Their finds and research in [[East Africa]] and and the prior work of [[Raymond Dart]] and [[Robert Broom]] in south Africa eventually convinced most paleoanthropologists that humans did indeed evolve in Africa. In 1959, at the Frida Leakey Korongo (FLK) site (named after Louis' first wife), Mary Leakey found remains of the robust australopithecine ''[[Zinjanthropus boisei]]'' (now known as ''Paranthropus boisei'')—which she dubbed the "Nutcracker Man"; its age, 1.75 million years, radically altered accepted ideas about the time scale of [[human evolution]]. In addition to an abundance of faunal remains the Leakeys found more than 2,000 stone tools and lithic flakes, most of which they classified as [[Oldowan]] (of Olduvai) tools. In 1960, the Leakeys' son [[Jonathan Leakey|Jonathan]] found a jaw fragment that proved to be the first fossil specimen of ''[[Homo habilis]]''.


In the late 1990s and early 2000s, Professor Fidelis Masao of the Open University of Tanzania led his team to excavate at Olduvai Gorge. These researchers focused on stone tools and animal bones bearing butchery marks to reveal the activities of long-ago human ancestors. Masao also studied the [[rock art]] paintings found in the region.
XXX===In the late 1990s and early 2000s, Professor Fidelis Masao of the Open University of Tanzania led his team to excavate at Olduvai Gorge. These researchers focused on stone tools and animal bones bearing butchery marks to reveal the activities of long-ago human ancestors. Masao also studied the [[rock art]] paintings found in the region.


The [[geology]] of Olduvai Gorge and the surrounding region was studied in detail by Richard L. Hay, who worked at the site between 1961 and 2002. His finding revealed, millions of years ago, the site was a large lake, with shores covered with deposits of [[volcanic ash]]. Around 500,000 years ago, [[seismic activity]] diverted a nearby stream which began to cut down into the sediments, revealing seven main layers in the walls of the gorge.
Researchers have dated Olduvai Gorge layers with [[radiometric dating]] of the embedded [[artifact (archaeology)|artifact]]s, using [[potassium-argon dating|potassium-argon]] and [[argon–argon dating|argon-argon]] methodology. Geologist Richard L. Hay studied the Olduvai Gorge and surrounding region between 1961 and 2002. His findings revealed that the site once contained a large lake, with shores covered by deposits of [[volcanic ash]]. Around 500,000 years ago, [[seismic activity]] diverted a nearby stream which proceeded to cut down through the sediments, revealing seven main layers in the walls of the gorge.


The name Olduvai is a misspelling of '''Oldupai Gorge''', which was adopted as the official name in 2005. Oldupai is the [[Maasai language|Maasai]] word for the wild sisal plant ''[[Sansevieria ehrenbergii]]'', which grows in the gorge.<ref>[http://www.basecamptanzania.com/NP_OldupaiGorge.htm Oldupai Gorge], Base Camp Tanzania</ref>
The name Olduvai is a misspelling of '''Oldupai Gorge''', which was adopted as the official name in 2005. Oldupai is the [[Maasai language|Maasai]] word for the wild sisal plant ''[[Sansevieria ehrenbergii]]'', which grows in the gorge.<ref>[http://www.basecamptanzania.com/NP_OldupaiGorge.htm Oldupai Gorge], Base Camp Tanzania</ref>


===Occupation===
===Occupation===
''Homo habilis'' is thought to have occupied the site from 1.9 to 1.2 million years ago. ''Paranthropus boisei'' was found to occupy the site from approximately 1.8 million years ago until 1.2 million years ago. ''Homo erectus'' remains were found and dated at the site from 1.2 million years ago until 700,000 years ago. ''Homo sapiens'' came to occupy the gorge 17,000 years ago.
''Homo habilis'' occupied Olduvai from 1.9 mya. The australopithecine ''Paranthropus boisei'' was found to occupy the site from approximately 1.8 until 1.2 mya. Remains of ''Homo erectus'' have been dated at the site from 1.2 mya until 700,000 years ago. ''Homo sapiens'' came to occupy the gorge some 17,000 years ago.


==Significance==
==Significance==


===Toolmaking===
===Toolmaking===
In the 1930s, as Mary and Louis Leakey searched for earliest stone tools in east Africa, many people were skeptical that Africa was the place where humans evolved. Yet, when the Leakeys found tools in Olduvai Gorge, evidence turned in their favor. These Oldowan tools had sharp and shaped edges. [[Lithic flake]]s were taken off in the intentional shaping of the tools' points.
In the 1930s, as Mary and Louis Leakey opted to search for stone tools in [[East Africa]], many if not most scholars were skeptical that Africa was the place where humans evolved. The Leakeys soon turned the evidence that confirmed their intuition. They found stone tools in the lowest (oldest) geological beds (see below). These tools presented both shaped edges and sharp points; and [[lithic flake]]s—struck off the core stone in the intentional shaping of those points and edges—were found in copious amounts.


The Leakeys recorded the particular locations in which the tools were found and compared these positions to locations where the [[raw materials]] originated. When these tools were found to have been transported up to 9 miles from the materials' place of origin, this suggested cognitive capacities to plan and think, and also to carry materials. While these Oldowan tools were found in the same [[stratum]] as the ''Australopithecus'' specimen, the multitude of other hominin fossils found dating back to two million years ago complicated the discussion of which species was, in fact, the toolmaker.
The Leakeys mapped locations where the tools were found and the sites where the [[raw materials]] (stone cobbles) originated. They determined that some tools were found to have been transported up to nine miles from the place of origin, which suggested cognitive capacities to think and plan, and to execute, with abstract thought and purpose of mind. The Oldowan tools were found in the same [[stratum]] as the ''Australopithecus'' specimen, but the large number of other hominin fossils dating back to two mya complicated the discussion as to which species was, in fact, the toolmaker.


The first species found by the Leakeys, ''Zinjanthropus boisei'' or ''[[Australopithecus boisei]]'' (renamed and still debated as ''Paranthropus boisei''), featured a [[sagittal crest]] and large [[molars]]. These attributes suggested the species engaged in heavy chewing, indicating a tough [[diet (nutrition)|diet]] consisting of [[tubers]], [[nut (fruit)|nut]]s, and [[seeds]].
The first species found by the Leakeys, ''Zinjanthropus boisei'' or ''[[Australopithecus boisei]]'' (renamed and still debated as ''Paranthropus boisei''), featured a [[sagittal crest]] and large [[molars]], which attributes suggested the species engaged in heavy chewing, indicating a [[diet (nutrition)|diet]] of tough plant material, including [[tubers]], [[nut (fruit)|nut]]s, and [[seeds]]—and possibly large quantities of [[grasses]] and [[sedges]].<ref>{{cite journal |last1=Macho |first1=Gabriele A. |year=2014 |title=Baboon Feeding Ecology Informs the Dietary Niche of Paranthropus boisei |journal=PLoS ONE |volume=9 |issue=1 |pages=84942 |pmid=24416315 |pmc=3885648 |bibcode=2014PLoSO...984942M |doi=10.1371/journal.pone.0084942}}</ref>


Conversely, the Leakeys' 1960s find held many different characteristics. Firstly, its lack of sagittal crest and much more rounded [[braincase]] suggested it was not an australopithecine. This newer fossil's skull also suggested a much bigger brain capacity than the previously found ''Australopithecus boisei''. These stark differences indicated this fossil must have belonged to a different species, eventually named ''Homo habilis''. Its cognitive capacity and decreased teeth size identified ''Homo'' as the toolmaker.
Conversely, the Leakeys' 1960s finds presented different characteristics. The skull lacked of a sagittal crest and the [[braincase]] was much more rounded, suggesting it was not australopithecine. The larger braincase suggested a larger brain capacity than that of ''Australopithecus boisei''. These important differences indicated a different species, which eventually was named ''Homo habilis''. Its larger brain capacity and decreased teeth size pointed to ''Homo'' as the probable toolmaker.


The lowest (oldest) tools located were [[Oldowan]] which consisted of pebbles chipped on one edge.<ref name=Langer>{{cite book|title=An Encyclopedia of World History| editor-last = Langer | editor-first = William L. |edition = 5th | publisher = Houghton Mifflin Company| location = Boston, MA| year = 1972 | isbn = 0-395-13592-3|pages = 9}}</ref> Above this were true [[hand-axe]], [[Chellean]], and [[Acheulean]] industries. Higher still are located [[Lavalloisean]] and finally the [[Stillbay]] implements.<ref name=Langer/> Mary Leakey herself developed Oldowan A,B, and C linking them to Modes one assemblages. Today her work remains a foundation for assessing local, regional, and continent-wide changes in stone tool-making during the early Pleistocene. It also helps to consider which species of hominins were responsible for the changes in stone tool over time.<ref>{{cite book|last1=Barham|first1=Lawrence|last2=Mitchell|first2=Peter|title=The First Aftricans|date=2008|publisher=Cambridge University Press|page=126}}</ref>
The oldest tools at Olduvai, found at the lowest layer and classified as [[Oldowan]], consists of pebbles chipped on one edge.<ref name=Langer>{{cite book|title=An Encyclopedia of World History| editor-last = Langer | editor-first = William L. |edition = 5th | publisher = Houghton Mifflin Company| location = Boston, MA| year = 1972 | isbn = 0-395-13592-3|pages = 9}}</ref> Above this layer, and later in time, are the true [[hand-axe]] industries, the [[Chellean]] and the [[Acheulean]]. Higher still (and later still) are located [[Lavalloisean]] artifacts, and finally the [[Stillbay]] implements.<ref name=Langer/> Oldowan tools in general are called "pebble tools" because the blanks chosen by the stone knapper already resembled, in pebble form, the final product.<ref>Napier, John. 1960. "Fossil Hand Bones from Olduvai Gorge." in ''Nature", December 17th edition.</ref> Mary Leakey classified the Oldowan tools according to usage; she developed Oldowan A,B, and C categories, linking them to [[Oldowan|Modes 1, 2, and 3]] assemblages classified according to mode of manufacture. Her work remains a foundation for assessing local, regional, and continental changes in stone tool-making during the early Pleistocene, and aids in assessing which hominins were responsible for the several changes in stone tool technology over time.<ref>{{cite book|last1=Barham|first1=Lawrence|last2=Mitchell|first2=Peter|title=The First Aftricans|date=2008|publisher=Cambridge University Press|page=126}}</ref>


It is not known for sure which hominin species was first to create Oldowan tools. The emergence of tool culture has also been associated with the pre-''Homo'' species ''[[Australopithecus garhi]]'',<ref name="de Heinzelin">{{cite journal | last1 = De Heinzelin | first1 = J | last2 = Clark | first2 = JD | last3 = White | first3 = T | last4 = Hart | first4 = W | last5 = Renne | first5 = P | last6 = Woldegabriel | first6 = G | last7 = Beyene | first7 = Y | last8 = Vrba | first8 = E | title = Environment and behavior of 2.5-million-year-old Bouri hominids | journal = Science | volume = 284 | issue = 5414 | pages = 625–9 | year = 1999 | pmid = 10213682 | doi=10.1126/science.284.5414.625}}</ref> <!------>and its flourishing is associated with the early species ''[[Homo habilis]]'' and ''[[Homo ergaster]]''. Beginning 1.7 million years ago, early ''[[Homo erectus]]'' apparently inherited Oldowan technology and refined it into the Acheulean industry.<ref name="Meat">{{ Cite journal | last=Richards|first=M.P.| title=A brief review of the archaeological evidence for Palaeolithic and Neolithic subsistence| journal=European Journal of Clinical Nutrition | volume =56 Supplement 1, March 2002| date=December 2002|issue =12 |pages =1270–1278 |
A significant change took place between Bed I and II at Olduvai Gorge at around 1.5 m.y.a. Flake size increased, bifacial edges were present more and their length increased, and signs of battering on artifacts increased. The implications of these factors, among others, are that after this pivotal time period hominids became better tool makers, used tools more, and transported tools more.<ref name="Kimura, Yuki. C 2002">{{cite book|author=Kimura, Yuki. C|title=Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge|date=2002|publisher=Journal of Human Evolution|volume=43}}</ref>
url=http://www.nature.com/ejcn/journal/v56/n12/full/1601646a.html | doi=10.1038/sj.ejcn.1601646 | pmid=12494313 | postscript=<!-- Bot inserted parameter. Either remove it; or change its value to "." for the cite to end in a ".", as necessary. -->{{inconsistent citations}}}} .</ref>


===Raw materials===
====Dating of beds====
Oldowan tools occur in Beds I–IV at Olduvai Gorge. Bed I, dated 1.85 to 1.7 mya, contains Oldowan tools and fossils of ''[[Paranthropus boisei]]'' and ''[[Homo habilis]]'', as does Bed II, 1.7 to 1.2 mya. ''H. habilis'' gave way to ''Homo erectus'' at about 1.6 mya, but ''P. boisei'' persisted. Oldowan tools continue to Bed IV at 800,000 to 600,000 before present ([[Before Present|BP]]). A significant change took place between Beds I and II at about 1.5 mya. Flake size increased, the length of bifacial edges (as opposed to single-face edges) occurred more frequently and their length increased, and signs of battering on other artifacts increased. Some likely implications of these factors, among others, are that after this pivotal time hominins used tools more frequently, became better at making tools, and transported tools more often.<ref name="Kimura, Yuki. C 2002">{{cite book|author=Kimura, Yuki. C|title=Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge|date=2002|publisher=Journal of Human Evolution|volume=43}}</ref>
To make Oldowan lithics in Olduvai Gorge, lava and quartz were usually used. And only in specific period (1.65-1.53 m.y.a), chert was used and it causes huge differences between the each assemblages of Olduvai Gorge.<ref name="Kimura, Yuki. C 2002"/>

====Raw materials====
Lava and quartz were used to make tools in Olduvai Gorge. Only in the period 1.65 to 1.53 ma was chert used, and it presents a significant difference in appearance among the assemblages of Olduvai Gorge.<ref name="Kimura, Yuki. C 2002"/>


===Hunters or scavengers?===
===Hunters or scavengers?===
Though substantial evidence of hunting and [[scavenging]] has been discovered at the site, it is believed by archaeologists{{Who|date=October 2012}} that the hominins that inhabited the area between 1.9 and 1.7 million years ago spent the majority of their time gathering wild [[plant]] foods, such as [[berries]], tubers and [[root]]s. Though substantial archaeological evidence for [[meat]] in ancient hominin diets exists, early hominins were most likely not relying heavily on meat for [[nutrition]]. This speculation about the amount of meat in their diets comes from comparative studies with a close relative of early humans: the [[chimpanzee]]. The chimpanzee's diet only consists of about 5% meat. Furthermore, modern hunter-gatherers' diets also do not consist of a large amount of meat. As a result, the majority of the [[calories]] in both their diets came from plant sources. By the [[middle-range theory (archaeology)|middle-range theory]] or [[bridging arguments]], it can be assumed that early hominins also had similar diet proportions. These bridging arguments are used by archaeologists to explain past behaviors and include an underlying assumption of [[uniformitarianism]].
Though substantial evidence of hunting and [[scavenging]] has been discovered at Olduvai Gorge, it is believed by archaeologists{{Who|date=October 2012}} that hominins inhabiting the area between 1.9 and 1.7 mya spent the majority of their time gathering wild [[plant]] foods, such as [[berries]], tubers and [[root]]s. The earliest hominins most likely did not rely on meat for the bulk of their [[nutrition]]. Speculation about the amount of meat in their diets is inferred from comparative studies with a close relative of early hominins: the modern [[chimpanzee]]. The chimpanzee's diet in the wild consists of only about five percent as meat. And the diets of modern hunter-gatherers do not include a large amount of meat. That is, most of the [[calories]] in both groups' diets came from plant sources. Thus, it can be assumed that early hominins had similar diet proportions, (see the [[middle-range theory (archaeology)|middle-range theory]] or [[bridging arguments]]—bridging arguments are used by archaeologists to explain past behaviors, and they include an underlying assumption of [[uniformitarianism]].)
Much of the information about early hominins comes from tools and piles of [[garbage]] from the sites such as the FLK-Zinjanthropus (also known as FLK-Zinj and where the "Zinj" skull was discovered) in Olduvai Gorge. Early hominins picked special types of rocks that would break in a predictable manner when "worked" to create tools, and carried these rocks from deposits several miles away. By fitting rock fragments back together like a puzzle, archaeologists, such as Fiona Marshall states in her article "Life in Olduvai Gorge", have been able to determine the early hominins, "knew the right angle to hit the cobble, or core, in order to successfully produce sharp-edged flakes. Such flakes were used to cut meat off animal carcasses. Shaped cobbles (called choppers) were probably also used to extract the marrow from inside the bones, or to chop up plant foods."
===Much of the information about early hominins comes from tools and debris piles of [[lithic flakes]] from such sites as FLK-Zinjanthropus in Olduvai Gorge. Early hominins selected specific types of rocks that would break in a predictable manner when "worked", and carried these rocks from deposits several miles away. Archaeologists such as Fiona Marshall fitted rock fragments back together like a puzzle. She states in her article "Life in Olduvai Gorge" that early hominins, "knew the right angle to hit the cobble, or core, in order to successfully produce sharp-edged flakes ...". She noted that selected flakes then were used to cut meat from animal carcasses, and shaped cobbles (called choppers) were used to extract [[Bone marrow|marrow]] and to chop tough plant material.


[[Bird]], [[fish]], [[amphibian]], and large [[mammal]] bone fragments were found at the FLK-Zinj site, some of which had marks on them. These could have been made by hominins breaking open the bones for [[Bone marrow|marrow]], using tools to strip the meat, or from [[carnivores]] which had gnawed on the bones. Since both kinds of marks are present on them, some archaeologists, namely Lewis Binford, think the hominins at FLK-Zinj scavenged the meat or marrow left over from carnivore kills. Others like Henry Bunn believe hominins hunted these animals and the carnivores chewed on the bones left over.<ref>{{cite book|last=Bunn|first=Henry|title=Meat Made Us Human|year=2007|publisher=Oxford University Press|location=New York|isbn=0195183460|pages=191–211|editor=Peter Ungar}}</ref> This controversial point is still debated today, but archaeologist Pat Shipman's study proved the evidence of scavenging was most common, meaning the majority of carnivore teeth marks came before the cut marks. Other findings during Shipman's research at FLK-Zinj revealed many of the [[wildebeest]] bones found at the site were of an adult, male wildebeest, and this indicates humans were hunting these animals, as carnivores, such as [[hyenas]], tend to hunt the weak, young and elderly. This would indicate humans were not only scavenging, but hunting, as well. The issue of hunting versus gathering at Olduvai Gorge is clearly a controversial one.<ref>{{cite book|last=Ungar|first=Peter|title=Evolution of the Human Diet|year=2007|publisher=Oxford University Press|location=New York|isbn=0195183460|editor=Peter Ungar}}</ref> Further evidence found at nearby sites helped to clarify some of this debate.
Bone fragments of birds, fish, [[amphibian]]s, and large [[mammal]]s were found at the FLK-Zinj site, many of which were scarred with marks. These likely were made by hominins breaking open the bones for marrow, using tools to strip the meat, or by [[carnivores]] having gnawed the bones. Since several kinds of marks are present together, some archaeologists including Lewis Binford think that hominins scavenged the meat or marrow left over from carnivore kills. Others like Henry Bunn believe the hominins hunted and killed these animals, and carnivores later chewed the bones.<ref>{{cite book|last=Bunn|first=Henry|title=Meat Made Us Human|year=2007|publisher=Oxford University Press|location=New York|isbn=0195183460|pages=191–211|editor=Peter Ungar}}</ref> This issue is still debated today, but archaeologist Pat Shipman provided evidence that scavenging was probably the more common practice; she published that the majority of carnivore teeth marks came before the cut marks. Another finding by Shipman at FLK-Zinj is that many of the [[wildebeest]] bones found there are over-represented by adult and male bones; and this may indicate that hominins were systematically hunting these animals as well as scavenging them. The issue of hunting versus gathering at Olduvai Gorge is still a controversial one.<ref>{{cite book|last=Ungar|first=Peter|title=Evolution of the Human Diet|year=2007|publisher=Oxford University Press|location=New York|isbn=0195183460|editor=Peter Ungar}}</ref>


==Gallery==
==Gallery==
<gallery class="center" widths="145px">
<gallery class="center" widths="175px">
Olduvai stone chopping tool.jpg|The oldest object in the [[British Museum]]
Olduvai stone chopping tool.jpg|The oldest object in the [[British Museum]]
Plaque marking the discovery of Australopithecus in Tanzania.jpg|The spot where the first ''A. boisei'' was discovered in Tanzania
Plaque marking the discovery of Australopithecus in Tanzania.jpg|The spot where the first ''A. boisei'' was discovered in Tanzania

Revision as of 02:04, 13 July 2015

Olduvai Gorge
Oldupai Gorge
Olduvai Gorge is located in Tanzania
Olduvai Gorge
Olduvai Gorge
Olduvai Gorge in Tanzania
Length48 kilometres (30 mi)

Olduvai Gorge, or Oldupai Gorge, in Tanzania is one of the most important paleoanthropological sites in the world; it has proven invaluable in furthering understanding of early human evolution. =\\=Homo habilis, probably the first early human species, occupied Olduvai Gorge approximately 1.9 million years ago (mya); then came a contemporary australopithecine, Paranthropus boisei, 1.8 mya, and then Homo erectus, 1.2 mya. Homo sapiens is dated to have occupied the site 17,000 years ago. A steep-sided ravine in the Great Rift Valley that stretches across East Africa, it is about 48 km (30 mi) long, and is located in the eastern Serengeti Plains in the Arusha Region not far, about 45 km, from Laetoli, another important archaeological site of early human occupation. The British/Kenyan paleoanthropologist-archeologist team Mary and Louis Leakey established and developed the excavation and research programs at Olduvai Gorge which achieved great advances of human knowledge and world-renown status.

The site is significant in showing the increasing developmental and social complexities in the earliest humans, or hominins, largely as revealed in the production and use of stone tools. And prior to tools, the evidence of scavenging and hunting—highlighted by the presence of gnaw marks that predate cut marks—and of the ratio of meat versus plant material in the early hominin diet. The collecting of tools and animal remains in a central area is evidence of developing social interaction and communal activity. All these factors indicate increase in cognitive capacities at the beginning of the period of hominids transitioning to hominin—that is, to human—form and behavior.

History

Olduvai Gorge from space
Topography map of the Olduvai Gorge.
Close-up of monolith
Panoramic view

Research

German neurologist Wilhelm Kattwinkel traveled to Olduvai Gorge in 1911,[1] where he observed many fossil bones of an extinct three-toed horse. Inspired by Kattwinkel's discovery, German geologist Hans Reck led a team to Olduvai in 1913. There, he found hominin remains, but the start of World War I halted his research. In 1929, Louis Leakey visited Reck and viewed the Olduvai fossils; he became convinced that Olduvai Gorge held critical information on human origins, and he proceeded to mount an expedition there.

Louis and Mary Leakey are responsible for most of the excavations and discoveries of the hominin fossils in Olduvai Gorge. Their finds and research in East Africa and and the prior work of Raymond Dart and Robert Broom in south Africa eventually convinced most paleoanthropologists that humans did indeed evolve in Africa. In 1959, at the Frida Leakey Korongo (FLK) site (named after Louis' first wife), Mary Leakey found remains of the robust australopithecine Zinjanthropus boisei (now known as Paranthropus boisei)—which she dubbed the "Nutcracker Man"; its age, 1.75 million years, radically altered accepted ideas about the time scale of human evolution. In addition to an abundance of faunal remains the Leakeys found more than 2,000 stone tools and lithic flakes, most of which they classified as Oldowan (of Olduvai) tools. In 1960, the Leakeys' son Jonathan found a jaw fragment that proved to be the first fossil specimen of Homo habilis.

XXX===In the late 1990s and early 2000s, Professor Fidelis Masao of the Open University of Tanzania led his team to excavate at Olduvai Gorge. These researchers focused on stone tools and animal bones bearing butchery marks to reveal the activities of long-ago human ancestors. Masao also studied the rock art paintings found in the region.

Researchers have dated Olduvai Gorge layers with radiometric dating of the embedded artifacts, using potassium-argon and argon-argon methodology. Geologist Richard L. Hay studied the Olduvai Gorge and surrounding region between 1961 and 2002. His findings revealed that the site once contained a large lake, with shores covered by deposits of volcanic ash. Around 500,000 years ago, seismic activity diverted a nearby stream which proceeded to cut down through the sediments, revealing seven main layers in the walls of the gorge.

The name Olduvai is a misspelling of Oldupai Gorge, which was adopted as the official name in 2005. Oldupai is the Maasai word for the wild sisal plant Sansevieria ehrenbergii, which grows in the gorge.[2]

Occupation

Homo habilis occupied Olduvai from 1.9 mya. The australopithecine Paranthropus boisei was found to occupy the site from approximately 1.8 until 1.2 mya. Remains of Homo erectus have been dated at the site from 1.2 mya until 700,000 years ago. Homo sapiens came to occupy the gorge some 17,000 years ago.

Significance

Toolmaking

In the 1930s, as Mary and Louis Leakey opted to search for stone tools in East Africa, many if not most scholars were skeptical that Africa was the place where humans evolved. The Leakeys soon turned the evidence that confirmed their intuition. They found stone tools in the lowest (oldest) geological beds (see below). These tools presented both shaped edges and sharp points; and lithic flakes—struck off the core stone in the intentional shaping of those points and edges—were found in copious amounts.

The Leakeys mapped locations where the tools were found and the sites where the raw materials (stone cobbles) originated. They determined that some tools were found to have been transported up to nine miles from the place of origin, which suggested cognitive capacities to think and plan, and to execute, with abstract thought and purpose of mind. The Oldowan tools were found in the same stratum as the Australopithecus specimen, but the large number of other hominin fossils dating back to two mya complicated the discussion as to which species was, in fact, the toolmaker.

The first species found by the Leakeys, Zinjanthropus boisei or Australopithecus boisei (renamed and still debated as Paranthropus boisei), featured a sagittal crest and large molars, which attributes suggested the species engaged in heavy chewing, indicating a diet of tough plant material, including tubers, nuts, and seeds—and possibly large quantities of grasses and sedges.[3]

Conversely, the Leakeys' 1960s finds presented different characteristics. The skull lacked of a sagittal crest and the braincase was much more rounded, suggesting it was not australopithecine. The larger braincase suggested a larger brain capacity than that of Australopithecus boisei. These important differences indicated a different species, which eventually was named Homo habilis. Its larger brain capacity and decreased teeth size pointed to Homo as the probable toolmaker.

The oldest tools at Olduvai, found at the lowest layer and classified as Oldowan, consists of pebbles chipped on one edge.[4] Above this layer, and later in time, are the true hand-axe industries, the Chellean and the Acheulean. Higher still (and later still) are located Lavalloisean artifacts, and finally the Stillbay implements.[4] Oldowan tools in general are called "pebble tools" because the blanks chosen by the stone knapper already resembled, in pebble form, the final product.[5] Mary Leakey classified the Oldowan tools according to usage; she developed Oldowan A,B, and C categories, linking them to Modes 1, 2, and 3 assemblages classified according to mode of manufacture. Her work remains a foundation for assessing local, regional, and continental changes in stone tool-making during the early Pleistocene, and aids in assessing which hominins were responsible for the several changes in stone tool technology over time.[6]

It is not known for sure which hominin species was first to create Oldowan tools. The emergence of tool culture has also been associated with the pre-Homo species Australopithecus garhi,[7] and its flourishing is associated with the early species Homo habilis and Homo ergaster. Beginning 1.7 million years ago, early Homo erectus apparently inherited Oldowan technology and refined it into the Acheulean industry.[8]

Dating of beds

Oldowan tools occur in Beds I–IV at Olduvai Gorge. Bed I, dated 1.85 to 1.7 mya, contains Oldowan tools and fossils of Paranthropus boisei and Homo habilis, as does Bed II, 1.7 to 1.2 mya. H. habilis gave way to Homo erectus at about 1.6 mya, but P. boisei persisted. Oldowan tools continue to Bed IV at 800,000 to 600,000 before present (BP). A significant change took place between Beds I and II at about 1.5 mya. Flake size increased, the length of bifacial edges (as opposed to single-face edges) occurred more frequently and their length increased, and signs of battering on other artifacts increased. Some likely implications of these factors, among others, are that after this pivotal time hominins used tools more frequently, became better at making tools, and transported tools more often.[9]

Raw materials

Lava and quartz were used to make tools in Olduvai Gorge. Only in the period 1.65 to 1.53 ma was chert used, and it presents a significant difference in appearance among the assemblages of Olduvai Gorge.[9]

Hunters or scavengers?

Though substantial evidence of hunting and scavenging has been discovered at Olduvai Gorge, it is believed by archaeologists[who?] that hominins inhabiting the area between 1.9 and 1.7 mya spent the majority of their time gathering wild plant foods, such as berries, tubers and roots. The earliest hominins most likely did not rely on meat for the bulk of their nutrition. Speculation about the amount of meat in their diets is inferred from comparative studies with a close relative of early hominins: the modern chimpanzee. The chimpanzee's diet in the wild consists of only about five percent as meat. And the diets of modern hunter-gatherers do not include a large amount of meat. That is, most of the calories in both groups' diets came from plant sources. Thus, it can be assumed that early hominins had similar diet proportions, (see the middle-range theory or bridging arguments—bridging arguments are used by archaeologists to explain past behaviors, and they include an underlying assumption of uniformitarianism.) ===Much of the information about early hominins comes from tools and debris piles of lithic flakes from such sites as FLK-Zinjanthropus in Olduvai Gorge. Early hominins selected specific types of rocks that would break in a predictable manner when "worked", and carried these rocks from deposits several miles away. Archaeologists such as Fiona Marshall fitted rock fragments back together like a puzzle. She states in her article "Life in Olduvai Gorge" that early hominins, "knew the right angle to hit the cobble, or core, in order to successfully produce sharp-edged flakes ...". She noted that selected flakes then were used to cut meat from animal carcasses, and shaped cobbles (called choppers) were used to extract marrow and to chop tough plant material.

Bone fragments of birds, fish, amphibians, and large mammals were found at the FLK-Zinj site, many of which were scarred with marks. These likely were made by hominins breaking open the bones for marrow, using tools to strip the meat, or by carnivores having gnawed the bones. Since several kinds of marks are present together, some archaeologists including Lewis Binford think that hominins scavenged the meat or marrow left over from carnivore kills. Others like Henry Bunn believe the hominins hunted and killed these animals, and carnivores later chewed the bones.[10] This issue is still debated today, but archaeologist Pat Shipman provided evidence that scavenging was probably the more common practice; she published that the majority of carnivore teeth marks came before the cut marks. Another finding by Shipman at FLK-Zinj is that many of the wildebeest bones found there are over-represented by adult and male bones; and this may indicate that hominins were systematically hunting these animals as well as scavenging them. The issue of hunting versus gathering at Olduvai Gorge is still a controversial one.[11]

Gallery

See also

References

  1. ^ Maier, Gerhard, African Dinosaurs Unearthed: The Tendaguru Expeditions, Indiana University Press, 2003, p. 116 ISBN 978-0253342140
  2. ^ Oldupai Gorge, Base Camp Tanzania
  3. ^ Macho, Gabriele A. (2014). "Baboon Feeding Ecology Informs the Dietary Niche of Paranthropus boisei". PLoS ONE. 9 (1): 84942. Bibcode:2014PLoSO...984942M. doi:10.1371/journal.pone.0084942. PMC 3885648. PMID 24416315.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  4. ^ a b Langer, William L., ed. (1972). An Encyclopedia of World History (5th ed.). Boston, MA: Houghton Mifflin Company. p. 9. ISBN 0-395-13592-3.
  5. ^ Napier, John. 1960. "Fossil Hand Bones from Olduvai Gorge." in Nature", December 17th edition.
  6. ^ Barham, Lawrence; Mitchell, Peter (2008). The First Aftricans. Cambridge University Press. p. 126.
  7. ^ De Heinzelin, J; Clark, JD; White, T; Hart, W; Renne, P; Woldegabriel, G; Beyene, Y; Vrba, E (1999). "Environment and behavior of 2.5-million-year-old Bouri hominids". Science. 284 (5414): 625–9. doi:10.1126/science.284.5414.625. PMID 10213682.
  8. ^ Richards, M.P. (December 2002). "A brief review of the archaeological evidence for Palaeolithic and Neolithic subsistence". European Journal of Clinical Nutrition. 56 Supplement 1, March 2002 (12): 1270–1278. doi:10.1038/sj.ejcn.1601646. PMID 12494313Template:Inconsistent citations{{cite journal}}: CS1 maint: postscript (link) .
  9. ^ a b Kimura, Yuki. C (2002). Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge. Vol. 43. Journal of Human Evolution.
  10. ^ Bunn, Henry (2007). Peter Ungar (ed.). Meat Made Us Human. New York: Oxford University Press. pp. 191–211. ISBN 0195183460.
  11. ^ Ungar, Peter (2007). Peter Ungar (ed.). Evolution of the Human Diet. New York: Oxford University Press. ISBN 0195183460.
  • 2004 - 2011. Olduvai Gorge – The Cradle of Mankind. http://www.tanzania- adventure.com/olduvai.htm, accessed December 2, 2011.
  • 2005. Chapter Outline. http://highered.mcgrawhill.com/sites/007299634x/student_view0/chapter2/chapter_outline.html, accessed December 2, 2011.
  • Cole, Sonia (1975) Leakey's Luck. Harcourt Brace Jovanvich, New York.
  • Colin Renfrew and Paul Bahn Archaeology Essentials 2007 Archaeology Essentials, 2nd Edition. Thames & Hudson Ltd, London.
  • Deocampo, Daniel M. (2004) "Authigenic clays in East Africa: Regional trends and paleolimnology at the Plio-Pleistocene boundary, Olduvai Gorge, Tanzania." Journal of Paleolimnology, vol. 31, p. 1-9.
  • Deocampo, Daniel M., Blumenschine, R.J., and Ashley, G.M. (2002). "Freshwater wetland diagenesis and traces of early hominids in the lowermost Bed II (~1.8 myr) playa lake-margin at Olduvai Gorge, Tanzania." Quaternary Research, vol. 57, p. 271-281.
  • Hay, Richard L. (1976) "Geology of the Olduvai Gorge." University of California Press, 203 pp.
  • E. Gengo, Michael. "Evidence of Human Evolution, Interpreting." Encyclopedia of Time: Science, Philosophy, Theology, & Culture. 2009. SAGE Publications. 5 Dec. 2011. <http://www.sage-ereference.com.proxy.lib.umich.edu/view/time/n200.xml>
  • Hominin Migrations Out of Africa. Lisa Young. Introduction to Prehistoric Archaeology. University of Michigan. October 2, 2011.
  • Joanne Christine Tactikos (2006) A landscape perspective on the Oldowan from Olduvai Gorge, Tanzania. ISBN 0-542-15698-9.
  • Leakey, L.S.B. (1974) By the evidence: Memoirs 1932-1951. Harcourt Brace Jovanavich, New York, ISBN 0-15-149454-1.
  • Leakey, M.D. (1971) Olduvai Gorge: Excavations in beds I & II 1960–1963. Cambridge University Press, Cambridge.
  • Leakey, M.D. (1984) Disclosing the past. Doubleday & Co., New York, ISBN 0-385-18961-3.
  • Marshall, Fiona. "Life in OLDUVAI GORGE." Calliope Sept. 1999: 16. General OneFile. Web. 4 Dec. 2011.
  • The First Stone Tool Makers. Lisa Young. Introduction to Prehistoric Archaeology. University of Michigan. September 25, 2011.

External links