Alison S. Brooks - US grants

The earliest known remains of anatomically modern humans occur in Africa. These remains are associated with people practicing Middle Stone Age (MSA) activities. The most intensive research on MSA peoples has been in the Cape Province of South Africa, but remains also have been uncovered in the Katanda area of the Semliki Valley in eastern Zaire. The Katanda sites are associated with fish remains, which suggest that aquatic resources may have been used much earlier than is evident at the South African sites. One of the Katanda sites also has yielded six barbed bone points, which are estimated to date from about 40,000 years before the present, the earliest known record of complex bone technology. This grant will permit further excavation of paleosol-related remains at the most productive of the Katanda sites. It also will permit surveying and mapping of the paleosol horizon along a roughly three kilometer exposure in order to place the archaeological findings in a broader regional context, and it will enable use of dosimeters and additional samples to determine more accurately the age of these MSA horizons. This project will expand on the work of previously sponsored excavations from a very promising site, which already has shed new light on Middle Stone Age peoples in central Africa. This work will contribute to our knowledge about the specific features of this site, and it also will contribute to our more general understandings of the processes by which evolution of modern humans was related to the development of new technologies and the exploitation of new environments and food sources.

9311709 Brooks The evolution of large savanna mammals, such as pigs, horses, and bovids, relates to the human story as both environmental and time/strategraphy indicators. This proposal will focus on one of the most prevalent large mammals commonly associated with hominids, the African Elephant lineage. This study will assess the variation in Elephas recki in order to describe the pattern of evolution seen in this fossil lineage, and will examine its utility as an indicator for early hominid sites. The goal is to study how elephants reflect the long term response of African ecosystems to changing biotic conditions, of which early human ancestors were a critical part. It will also involve advanced training of a graduate student. ***

9521879 BROOKS The Middle Stone Age is a period when anatomically modern humans replaced more archaic forms. Recent research findings in Africa have shown that economic activities of humans in this time may also have been associated with crucial behavioral changes. Excavation of Middle Stone Age sites is limited, however, and long sequences with good faunal preservation are rare. This project will continue work by an interdisciplinary team of archeologists, paleontologists, geologists, and geochemists at Middle Stone Age and Acheulean sites in the Aduma-Bouri regions of the Middle Awash Valley of Ethiopia. Continued excavations will focus on evidence of human economic activities in association with fossil lake shores and deltaic deposits. Parallel work will continue on the relatively little-known Middle Stone Age industries of the Aduma region and the later Acheulan sites at Bouri in order to establish a chronological and paleoenvironmental relationship between the sequences of these two regions. Research will include stratigraphic, paleolandscape, and paleoenvironmental reconstruction of the Aduma region and establishment of an absolute chronology using several techniques. The project will be coordinated with the work of a team led by T.D. White that is working sites about 30 km to the north. This project will continue what already has been a productive network of sites in central Ethiopia. The excellent preservation of materials has generated new insights into the evolution of marine-related industries. Of special significance is the potential to gain new insights into the behavior transformation of early humans from independent actors into communal entities who work together and employ relatively sophisticated tools.

9987590
Bernard Wood - George Washington University
IGERT: Integrative Human Evolutionary Biology

This Integrative Graduate Education and Research Training (IGERT) award supports the establishment of a multidisciplinary, multi-institutional, graduate training program of education and research on human evolutionary biology. The Human Evolutionary Biology Doctoral Program (HEBDP) is a graduate program linking anthropology with molecular and organismal biology, chemistry, engineering and geology that promotes interdisciplinary research emphasizing experimental and comparative methods for studying human evolutionary history. HEBDP is a collaboration between George Washington University, Howard University, the University of Maryland, the Smithsonian Institution, and other Washington DC area researchers. The evidence for our species' evolutionary history is well studied and of unquestionable social and scientific importance. Yet, despite a wealth of fossil, archaeological, molecular, paleoecological and comparative data, issues as basic as hominid phylogeny, the evolution of bipedal locomotion, diet, language and cognition, and the effects of environmental change on human evolution, and vice versa, remain poorly understood. These gaps in our knowledge partly occur because few students are trained in the new range of analytical, experimental and conceptual skills needed to test evolutionary hypotheses. HEBDP will combine coursework with innovative problem-based learning seminars, internships and research to train students in new methods for studying our species' fossil, archaeological and genetic records. Because human evolutionary research has broad social and medical implications, HEBDP includes training in skills required for the effective public dissemination of science.

IGERT is an NSF-wide program intended to meet the challenges of educating Ph.D. scientists and engineers with the multidisciplinary backgrounds and the technical, professional, and personal skills needed for the career demands of the future. The program is intended to catalyze a cultural change in graduate education by establishing new, innovative models for graduate education and training in a fertile environment for collaborative research that transcends traditional disciplinary boundaries. In the third year of the program, awards are being made to nineteen institutions for programs that collectively span all areas of science and engineering supported by NSF. The intellectual foci of this specific award reside in the Directorates for Social, Behavioral, and Economic Sciences; Biological Sciences; Mathematical and Physical Sciences; Engineering; Geosciences; and Education and Human Resources.

Humans have impacted global biodiversity via habitat degradation and destruction, the introduction of invasive species, and direct harvesting of plant and animal populations. The archaeological record provides abundant evidence that modern humans living in small-scale societies are capable of substantial impacts on past ecosystems. The antiquity of human impacts on past environments is much debated, especially concerning the extent to which humans contributed to mass extinctions of megafauna during the past 100,000 years. In this project the coPI will evaluate the hypothesis that human foragers contributed to large mammal extinctions along the southern coast of South Africa during the Pleistocene/Holocene environmental transition, between 12-10 thousand years ago. It is generally agreed that environmental change played an important role in these extinctions, although possible human contributions to the southern African extinctions remain unclear. The research will involve an analysis of faunal remains from southern African archaeological sites spanning the past 125 thousand years. A primary objective is to determine whether Later Stone Age humans (<40 thousand years ago) exerted greater predation pressure on large mammal populations than their Middle Stone Age (~250-40 thousand years ago) predecessors. The coPI will examine dental remains of fossil ungulates to reconstruct the age structures of animal populations and to examine the effects of human predation pressure on wildlife populations through time. In addition, the coPI will determine whether there is evidence for anthropogenic resource depression, a decline in wildlife population densities resulting from human predation pressure, at the time of the southern African extinctions. This will involve an investigation of human subsistence change across the Pleistocene/Holocene transition at Boomplaas Cave, located in the Cango River Valley. The Boomplaas Cave faunal remains will be studied to determine how changes in prehistoric human diet reflect environmental shifts and/or anthropogenic resource depression.

Debate over the possible role of prehistoric human foragers on large mammal extinctions has been underway for over 150 years. While much research has focused on extinctions in North America, Australia, and Eurasia, the extinctions in Africa remain poorly understood. The results of this research will provide new insight into how the combined effects of human activities and environmental change have structured the ecosystems of southern Africa, particularly through their impact on large mammal populations. This project will also establish the time depth of human impacts on animal populations in southern Africa. In turn, this has implications concerning the hunting rights of indigenous peoples and wildlife conservation decisions, especially with respect to the fate of contemporary biodiversity and our attempts to understand and moderate the effects of global climate change.

This Integrative Graduate Education and Research Training (IGERT) award focuses on the evolution of the human brain, cognition, and related behavioral responses to environmental change. The program integrates cross-disciplinary research training in a unique mix of disciplines, namely archeology, biomechanics and engineering, cognitive science, comparative and experimental functional morphology, ecology, evolutionary and developmental biology, genetics, geochemistry, morphometrics, life history, molecular biology, neuroscience, and paleoclimatology. Innovative educational and training aspects include an emphasis on collaboration via group problem-based learning approaches, required laboratory rotations in two different disciplines, and seminars in ethics and professional conduct. The program combines George Washington University?s PhD program in Hominid Paleobiology with the Howard University PhD in Physiology and Biophysics, together with faculty from the Smithsonian Institution and Johns Hopkins University?s Center for Functional Anatomy and Evolution, The collaboration with Howard University (an HBCU) and existing and planned internship programs for undergraduates will increase the recruitment of underrepresented minorities. Outreach activities include a required internship in the public understanding of science, in conjunction with area institutions such as the National Geographic Society, USA Today, NPR, the National Academy of Sciences, American Anthropological Association, local schools and others. The program offers research-training opportunities at major international institutions in Europe (e.g., Max Planck Institut für evolutionäre Anthropologie (MPIEA); Swedish Museum of Natural History; Università degli Studi di Firenze?s Laboratori di Antropologia; University of Bordeaux), China and Africa. IGERT is an NSF-wide program intended to meet the challenges of educating U.S. Ph.D. scientists and engineers with the interdisciplinary background, deep knowledge in a chosen discipline, and the technical, professional, and personal skills needed for the career demands of the future. The program is intended to catalyze a cultural change in graduate education by establishing innovative new models for graduate education and training in a fertile environment for collaborative research that transcends traditional disciplinary boundaries.

In contrast to their great ape relatives, humans have spread from their original home in a limited region of Africa to occupy and even dominate almost all terrestrial habitats. Their success has in part been attributed to the use of, and dependence on, technology of which stone tools represent the earliest evidence. The form of stone tools, together with data on their use and manufacture (knapping), also provide a long record of human cognitive development. Since the early period of tool production corresponds to major changes in the morphology of the hand, wrist and arm, researchers have suggested that increasing use of stone tools played a role in shaping modern human upper limb anatomy. The fracture mechanics involved in producing stone tools in different raw materials and the biomechanics of the upper limb during stone tool production, however, are not well understood. The interactive relationship of fracture mechanics and upper limb morphology on the resulting stone tool is also unclear. This project addresses these issues from an interdisciplinary perspective that integrates lithic analysis with experiments in fracture mechanics and biomechanics. Two main hypotheses will be tested: 1.) magnitude and direction of knapping forces required to produce specific flake morphologies can be predicted from raw material properties (i.e., toughness) and core shape, and, 2.) evolved upper limb morphology in Homo plays a key role in efficient stone tool production.
The research design involves fracture mechanics experiments on relevant raw materials, followed by a two phase analysis of knapping motions using a digital motion analysis system to study upper limb motion patterns and forces acting across the hand and wrist. The motion analysis study will involve ten experienced knappers replicating stone flakes and tools in two different raw materials from four different successive tool traditions (Oldowan, Acheulian, Levallois and Middle Stone Age). The two phases will involve the same tasks but in the second phase the knappers' wrists will be restrained to ~30° of anterior-posterior motion to simulate the primitive condition found in African apes and early hominins. Flakes and tools from the two phases will be compared and analyzed for the accuracy and efficiency of motions during the natural vs. the restrained condition. The goal of this study is to determine how fundamental variables involved in stone tool production (material toughness, fracture behavior, core shape and upper limb kinematics) interact to determine flake morphology, knapping accuracy, and energetic efficiency. The study will provide new insights into the advent and development of stone tool production and the evolution of the human upper limb. This in turn has significant clinical implications for understanding upper limb joint motions, variations in morphology, and the impact of injuries and degenerative bone diseases.

Symbolism, including language, is widely viewed as an essential element of modern human behavior. Documenting the evolutionary origins of such behavior, however, has proven difficult. Ochre pigments (iron oxides) form a major part of the evidence used to interpret when humans began communicating through symbols. Excavations at Olorgesailie, Kenya; Karonga, Malawi; and Twin Rivers, Zambia have yielded ochre artifacts that may indicate very early occurrences of symbolism. Yet mineral pigments may also form naturally in archaeological sites, or may have technological rather than symbolic uses. This project will evaluate and further develop analytical approaches to the chemical "fingerprinting" of ochre artifacts and sources from these three African localities. Using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry and Instrumental Neutron Activation Analysis to facilitate the matching of artifacts to source deposits, the doctoral student Andrew Zipkin (George Washington University), under the supervision of Dr. Alison Brooks, will demonstrate the extent to which human ancestors were willing to seek out and transport specific pigments. This project also will use color quantifying technologies to determine if Middle Stone Age humans exhibited color preferences in the ochres that they collected and modified. Color preference potentially suggests symbolic use of ochre since the meaning given to different colors, such as in national flags, is a well-known aspect of modern human behavior.

The dissertation's final aspect will be an experimental evaluation of proposed non-symbolic uses of ochre. The leading alternative explanation is that ochre was an ingredient in plant resin adhesives used to construct compound tools, like stone-tipped spears. In collaboration with material scientists, the investigators will measure the effectiveness of different ochre minerals in formulating adhesives to test if glue production rather than symbolic meaning could explain past ochre procurement choices.

The research will contribute to the development of international collaborations between American, Australian, Canadian, Malawian, and Zambian researchers, as well as outreach activities for the general public. The development of new analytical approaches for "fingerprinting" mineral sources will find broad application in usage not just by archaeologists, but also by art historians, state agencies investigating the illegal transport of stolen antiquities, and forensic scientists.