Extra knowledge on Jurmain
a) Fossil record of Homo habilis, the earliest Homo
Ever since the accidental discovery of Taung child (Australopithecus africanus) from South Africa in 1924, a number of Australopithecine fossil were excavated from East, West and South Africa. In 1960, almost seven decades after Dubois discovered Homo erectus from Java, Louis and Mary Leakey discovered an extraordinary partial skull from Olduvai Gorge in Tanzania, the same site from where Robust Australopithecus (also known as Paranthropus or Zinjanthropus boisei) was discovered. The skull belongs to a juvenile and it is dated to about 2 million year ago. It is derived from the Australopithecine by having relatively smaller face and larger cranial capacity. The estimated average cranial capacity of earlier Homo skull is 631cc, compared to 520 cc for all the measurable Paranthropus specimens and 442 cc for Australopithecus crania (McHanry, 1988). Recognizing the significance of these characteristics, Louis Leakey, Philip Tobias and John Napier convincingly gave a
new genus “Homo” and named it as Homo habilis, meaning ‘handy – man or skilled – man’, referring to the use and manufacture of stone tools.
In addition to fossil bone and teeth, some stone tools were also discovered from Olduvai Gorge. Initially it was thought to be the remains of Australopithecus, but later they were convinced that the discovered materials were of Homo habilis who really manufactured and used it. Thus, most anthropologists agreed that Homo habilis might be the first maker of stone tools and this marked the beginning of a lineage leading to modern human. Initially, reorganization of Homo habilis was met with skepticism. However, with additional finding from other parts of Africa, it confirms the presence of such early member of the genus. Now Homo habilis is found from Hadar and Omo in Ethiopia, Urcha in Malawi, Chemeron Formation and Koobi Fora in Kenya besides Oldovai Gorge in Tanzania.
About a decade after Homo habilis was discovered, in early 1970s, Richard Leakey and his team discovered a more intact skull of Homo habilis from Koobi Fora, Eastern shore of Lake Turkana. The skull was dated approximately 1.9 million year ago and known by the National Museums of Kenya catalog number KNM-ER 1470. This fossil greatly differed from the one discovered from Olduvai Gorge having a large cranial capacity of 775 cc. The difference between the largest specimen of Homo habilis or early Homo and the smallest specimen is too large to be grouped together under one single species. The cranial capacity of the largest specimen is almost one third larger than the smallest specimen (only 510 cc). Moreover, the smaller specimens have longer upper limbs compared to the larger specimen, which is a primitive feature. Hence, many scholars preferred to call the larger specimen with a new species name Homo rudolfensis. However, the two types of specimen have similar brain to body proportion. The specimen with large brain size has larger body and the one with small brain size has smaller body. So, many scholars claim that they were male and female individuals of the same species. Since both the fossils have same general body plan and overall morphology we can consider them as a single species – Homo habilis or early Homo. But not to have confusion between Homo habilis and Homo rudolfensis we will use the term ‘early Homo’ to mean both.
East Africa have yielded a wide variety of fossil remains predominantly Australopithecine along with early Homo and Homo erectus. Early Homo roamed in East Africa from about 2.0 to 1.4 million year ago (mya). The latest Australopithecine was seen in East Africa in about 1.5 mya and the earliest Homo erectus appeared in East Africa in 1.8 – 1.9 million year ago. By putting all these evidence together, it can be reasonably presumed that at least one species of early Homo evolved in East Africa about 2 million year ago, along with an Australopithecine species, coexisting contemporaneously for atleast a million year after which Australopithecines apparently disappeared forever. One lineage of this early Homo might have evolved into Homo erectus about 1.8 million year ago and all other species of early Homo became extinct sometime about 1.4 million year ago.
b) The Lower Paleolithic Period: Emergence of Human Culture
The oldest identifiable stone tools date to 2.6 mya, and it is from this evidence that archaeologists determine the beginning of the Lower Paleolithic period. The two major Lower Paleolithic stone tool industries or tool complexes are the Oldowan, which spans roughly 2.6–1.7 mya, and the Acheulian, which dates to 1.7–0.2 mya.
The name Oldowan was coined decades ago by Louis and Mary Leakey to describe early stone tools and archaeological sites found at Olduvai Gorge, Tanzania. Subsequent research elsewhere in East Africa unearthed Oldowan sites that are more than half a million years older than the oldest Olduvai Gorge locations. These Oldowan assemblages demonstrate that by 2.6 mya, hominins were already inventing and adopting cultural, rather than purely biological, means of dealing with the world around them.
The meager Oldowan archaeological evidence may seem unremarkable, especially when you consider that the cultural changes it reflects occurred so slowly that they would have been virtually unnoticeable to the Oldowan tool users themselves. Nevertheless, this seemingly insignificant beginning was profoundly important to the development of humans. As Thomas Plummer (2004, p.118) recently observed: “The appearance of Oldowan sites ca. 2.6 million years ago . . . may reflect one of the most important adaptive shifts in human evolution. Stone artifact manufacture, large mammal butchery, and novel transport and discard behaviors led to the accumulation of the first recognized archaeological debris.” These small steps also created a new phenomenon—the archaeological record, the source of the only direct evidence by which researchers can understand the cultural side of our biocultural evolution.
Oldowan tools are extremely rudimentary compared with the simplest known modern human technology. Assemblages mostly consist of stone flakes, which were used for cutting; hammerstones, used as the name implies; core tools such as choppers, which show considerable battering on their edges; and stone cores, which were used only as a source of flakes. These early hominins may have also made bone and wooden tools, but such implements have not survived in the archaeological record.
Most Oldowan stone tools were made by the “hard hammer” percussion method , which, as the name implies, means that these toolmakers simply took one rock and smashed it with another rock until they got the sharp flakes or cutting edge they wanted. The resulting tools typically owe most of their shape or form to that of the original pebble or cobble from which they were made. This pattern begins to change during the Acheulian, when we find tools that clearly are the result of the toolmakers sharing a common target design they wished to produce.
Compared with most hunter- gatherer tool kits from, say, 20,000 ya, Oldowan tools were of a generalized nature, where any given tool might serve several tasks. They were also relatively expedient tools, which means that they tended to be made when they were needed, used, and then discarded. Expedient tools are the opposite of curated tools, which are made, used, and kept (“curated”) in anticipation of future use. The overall trend, is for human tools to become both more specialized and more curated, but it took a long time for this trend to be measurable in the archaeological record. An important exception can be found in areas where suitable stones for tools do not occur naturally. In these cases, the available archaeological evidence suggests that Early Pleistocene hominins carried stones as much as 6 miles from their source areas. Oldowan tools are properly viewed as the oldest tools that archaeologists can reliably identify. Our knowledge of the beginnings of human toolmaking is complicated greatly by the rudimentary nature of the earliest tools and by factors of preservation that removed wooden and other organic tools from the archaeological record. It is reasonable to assume that early hominins were tool users for hundreds of thousands of years before the oldest identified Oldowan stone tools were made and used (Harris and Capaldo, 1993). New discoveries continue to push back the age of the earliest hominin tool use. Recently, for example, researchers found 3.39-million-year-old animal bones at Dikika, Ethiopia, that show stone tool cut marks and battering from the removal of meat and marrow (McPherron et al., 2010). It is important to note that the Dikika evidence is of the effects of tool use; no identifiable stone tools were found in association with the cut-marked animal bones. Nevertheless, Dikika is the latest and, thus far, the earliest example of evidence that the beginnings of hominin tool use (and, consequently, of hominin biocultural evolution) have deep roots in our past (de la Torre, 2011; Rogers and Semaw, 2009). The first tool-using hominin was likely one or more species of Australopithecus, but which species is far from clear.
So what did Lower Paleolithic hominins use Oldowan tools to do? They are best described as “tool-assisted” gatherers and meat scavengers. We can be reasonably certain that they were not hunters of big game, nor did their technology confer more than a minor competitive advantage over bigger, more aggressive savanna animals. If anything, these hominins were more equipped physically to be prey rather than hunter. Our earliest direct ancestors may have been inching their way up the food chain, but to get there, thousands of generations spent time waiting to pick over what was left after the real predators and scavengers ate their fill.
The Oldowan archaeological record is a controversial area of anthropological research. We are confident that early hominins created the earliest archaeological evidence of human cultural behavior. But which hominins, and why? How did they use the tools they made? Were they hunter, prey, or both? We have answers to these questions, but all too often, they are slippery, chameleon-like ones that can change dramatically with the next fossil find or archaeological excavation. It is a frustrating but fascinating area of science.