Anthropology 102: Introduction to Physical Anthropology
Professor Arnie Schoenberg
1. What are the major trends in hominin evolution?
Major Trends in Hominin Evolution are diet, cultural evolution, encephalization, language and speech Diet; In addition to forcing changes in locomotion that led to walking upright, the increasingly dry climate of east Africa over the last six million years forced changes in the diet of early hominins from the soft fruits of the tropical rain forest to the increasingly fibrous and tough foods available in open habitats.Early hominin diets are reconstructed partly based on the surface areas of the molars and the cross-sectional area of the body of the lower jaw (Collard & Wood 1999). Tooth area reveals the efficiency of food processing; whereas, the mandibular body size reflects the amount of force applied during processing. Humans are omnivores that favor nuts, fruit and meat. The chimpanzee diet is not much different from that of humans except in a greater emphasis on fruit, stems and leaves and less on meat. Chimpanzees do not differ particularly from modern humans in the efficiency and force of their dentition. However, only H. ergaster of the early hominins shared these dental dimensions with us. Australopithecines and the robust Paranthropus species, in particular, required more area for processing and more robust jaws. Paranthropus species especially relied on hard food items suggested by scratches on their teeth (Kay & Grine 1988). In general the earliest sites showing hominin activity are near lake margins where streams join or at rock outcrops, places with a variety of resources that can be exploited for longer periods (Larick & Ciochon 1996). This pattern changes after 2.0 m.y.a. as landscapes became more open. Fewer resources are exploited at any one locale, and individuals probably used several locales simultaneously which would have required a wide-ranging scavenging behavior. This shift happens after the appearance of relatively longer lower limbs and coincides with the first exit from Africa. By 1.7 m.y.a. it is the most common pattern and is associated with H. ergaster, H. erectus, and Acheulean tools. The first use of fire may be represented by burnt bones (1.5-1.0 m.y. old) found at the Swartkrans Cave in South Africa. Although we do not know if they used fire for cooking or at all, it is commonly believed that Homo erectus regularly ate meat. How they acquired it, however, whether by scavenging or hunting, is controversial (Klein 1999; Tappen 2001). It is more commonly accepted that Homo heidelbergensis hunted meat regularly.Cultural Evolution; bipedalism appeared after 5 m.y.a. and it is likely that these earliest hominins achieved a level of technology consistent with contemporary chimpanzee tool use (Ambrose 2001). The earliest stone tools date to 2.5 m.y.a. from Ethiopia, and likely as early in Kenya (Heinzelin et al. 1999; Klein 1999). The site in Ethiopia provides evidence of the disarticulation and deflveshing of large mammals and of long bones that were smashed open presumably to obtain the marrow. These early stone tools are lumped with the slightly later tools at Olduvai Gorge into the Oldowan Industry that lasted until 1.7-1.6 m.y.a.. Their shapes are mostly a function of the characteristics of the raw material used but represent skilled percussion flaking (well beyond the capacity of chimpanzees) that maximizes the production of sharp edges (Ambrose 2001). Larger stone cutting tools 10-17 cm. in length of the Acheulean Industry appeared around 1.5 m.y.a. at approximately the same time as Home ergaster / Homo erectus. They represent a long lived tool association and were produced as recently as 300,000 years ago (y.a.) by Homo heidelbergensis (Ambrose 2001). The Acheulean Industry is found only west and south of the “Movius Line” which curves from India-Bangladesh to northern England (with a few exceptions in...
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