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Drummond-Clarke RC. Bringing trees back into the human evolutionary story: recent evidence from extant great apes. Commun Integr Biol 2023; 16:2193001. [PMID: 36969387 PMCID: PMC10038020 DOI: 10.1080/19420889.2023.2193001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
Hypotheses have historically linked the emergence and evolution of defining human characteristics such as bipedal walking to ground-dwelling, envisioning our earliest ancestors as living in treeless savannahs (i.e. the traditional savannah hypothesis). However, over the last two decades, evidence from the fossil record combined with comparative studies of extant apes have challenged this hypothesis, instead favoring the importance of arboreality during key phases of hominin evolutionary history. Here we review some of these studies, including a recent study of savannah chimpanzees that provides the first model of how bipedalism could have been adaptive as an arboreal locomotor behavior in early hominins, even after the forests receded during the early Miocene-Pliocene transition. We suggest that whilst a shift to exploiting open habitats catalyzed hominin divergence from great apes, adaptations to arboreal living have been key in shaping what defines humans today, in counter to the traditional savannah hypothesis. Future comparative studies within and between great ape species will be instrumental to understanding variation in arboreality in extant apes, and thus the processes shaping human evolution over the last 3-7 million years.
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Affiliation(s)
- Rhianna C. Drummond-Clarke
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Institut für Zoologie und Evolutionsforschung, Friedrich Schiller Universität Jena, Jena, Germany
- CONTACT Rhianna C. Drummond-Clarke Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
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Drummond-Clarke RC, Kivell TL, Sarringhaus L, Stewart FA, Humle T, Piel AK. Wild chimpanzee behavior suggests that a savanna-mosaic habitat did not support the emergence of hominin terrestrial bipedalism. SCIENCE ADVANCES 2022; 8:eadd9752. [PMID: 36516260 PMCID: PMC9750136 DOI: 10.1126/sciadv.add9752] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 11/08/2022] [Indexed: 06/17/2023]
Abstract
Bipedalism, a defining feature of the human lineage, is thought to have evolved as forests retreated in the late Miocene-Pliocene. Chimpanzees living in analogous habitats to early hominins offer a unique opportunity to investigate the ecological drivers of bipedalism that cannot be addressed via the fossil record alone. We investigated positional behavior and terrestriality in a savanna-mosaic community of chimpanzees (Pan troglodytes schweinfurthii) in the Issa Valley, Tanzania as the first test in a living ape of the hypothesis that wooded, savanna habitats were a catalyst for terrestrial bipedalism. Contrary to widely accepted hypotheses of increased terrestriality selecting for habitual bipedalism, results indicate that trees remained an essential component of the hominin adaptive niche, with bipedalism evolving in an arboreal context, likely driven by foraging strategy.
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Affiliation(s)
| | - Tracy L. Kivell
- School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| | - Lauren Sarringhaus
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Department of Anthropology, University of Michigan, Ann Arbor, MI, USA
| | - Fiona A. Stewart
- Department of Anthropology, University College London, London, UK
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
| | - Tatyana Humle
- School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Alex K. Piel
- Department of Anthropology, University College London, London, UK
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3
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Stevenson DS, Wallace R. Biogeographical Modeling of Alien Worlds. ASTROBIOLOGY 2021; 21:831-844. [PMID: 33904766 DOI: 10.1089/ast.2020.2304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this article, we partially quantify the biological potential of an exoplanet. We employ a variety of biogeographical analyses, placing biological evolution in the context of the geological evolution of the planet as a whole. Terrestrial (as in Earthly) biodiversity is tightly constrained in terms of species richness by its environment. An organism's habitable environment may be considered its niche space or hypervolume in terms of the physical characteristics in which that organism can survive and reproduce. This fundamental niche forms the broader space in which the organism realizes its true niche in terms of its interactions with other species. Many of the physical characteristics can be determined from astrophysical constraints and are thus amenable for dissection. However, the geographical space that organisms occupy is driven by the geological evolution of a sizable telluric planet. In turn, this is driven by the progressive differentiation of its interior to produce increasingly felsic crust. Using a variety of available models, we can then constrain the available space that species can inhabit using species-area relationships. By considering a combination of astrophysical constraints and geographical space, we partially quantify the numbers of species that can inhabit the landscape that geology provides. Finally, we also identify a correlation between geomorphological scale and speciation, which, if validated, will allow further dissection of species diversity on alien worlds.
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Affiliation(s)
- David S Stevenson
- Science Department, Carlton le Willows Academy, Nottingham, United Kingdom
| | - Rodrick Wallace
- Division of Epidemiology, The New York State Psychiatric Institute at Columbia University, New York Psychiatric Institute, New York, USA
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4
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Revisiting the pedogenic carbonate isotopes and paleoenvironmental interpretation of Kanapoi. J Hum Evol 2020; 140:102549. [DOI: 10.1016/j.jhevol.2018.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 09/15/2018] [Accepted: 11/06/2018] [Indexed: 11/18/2022]
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5
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Seasonal and habitat effects on the nutritional properties of savanna vegetation: Potential implications for early hominin dietary ecology. J Hum Evol 2019; 133:99-107. [DOI: 10.1016/j.jhevol.2019.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 01/09/2019] [Accepted: 01/23/2019] [Indexed: 11/22/2022]
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6
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Peterson A, Abella EF, Grine FE, Teaford MF, Ungar PS. Microwear textures of Australopithecus africanus and Paranthropus robustus molars in relation to paleoenvironment and diet. J Hum Evol 2018; 119:42-63. [DOI: 10.1016/j.jhevol.2018.02.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 02/03/2018] [Accepted: 02/05/2018] [Indexed: 12/20/2022]
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7
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Environmental hydro-refugia demonstrated by vegetation vigour in the Okavango Delta, Botswana. Sci Rep 2016; 6:35951. [PMID: 27775028 PMCID: PMC5075895 DOI: 10.1038/srep35951] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 09/30/2016] [Indexed: 11/25/2022] Open
Abstract
Climate shifts at decadal scales can have environmental consequences, and therefore, identifying areas that act as environmental refugia is valuable in understanding future climate variability. Here we illustrate how, given appropriate geohydrology, a rift basin and its catchment can buffer vegetation response to climate signals on decadal time-scales, therefore exerting strong local environmental control. We use time-series data derived from Normalised Difference Vegetation Index (NDVI) residuals that record vegetation vigour, extracted from a decadal span of MODIS images, to demonstrate hydrogeological buffering. While this has been described previously it has never been demonstrated via remote sensing and results in relative stability in vegetation vigour inside the delta, compared to that outside. As such the Delta acts as a regional hydro-refugium. This provides insight, not only to the potential impact of future climate in the region, but also demonstrates why similar basins are attractive to fauna, including our ancestors, in regions like eastern Africa. Although vertebrate evolution operates on time scales longer than decades, the sensitivity of rift wetlands to climate change has been stressed by some authors, and this work demonstrates another example of the unique properties that such basins can afford, given the right hydrological conditions.
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Dirks PH, Placzek CJ, Fink D, Dosseto A, Roberts E. Using 10Be cosmogenic isotopes to estimate erosion rates and landscape changes during the Plio-Pleistocene in the Cradle of Humankind, South Africa. J Hum Evol 2016; 96:19-34. [DOI: 10.1016/j.jhevol.2016.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 03/05/2016] [Accepted: 03/07/2016] [Indexed: 10/21/2022]
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9
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Comment on "Deliberate body disposal by hominins in the Dinaledi Chamber, Cradle of Humankind, South Africa?" [J. Hum. Evol. 96 (2016) 145-148]. J Hum Evol 2016; 96:149-53. [PMID: 27289545 DOI: 10.1016/j.jhevol.2016.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 04/27/2016] [Accepted: 04/28/2016] [Indexed: 11/20/2022]
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10
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Brubaker AS, Coss RG. Effects of Single- and Mixed-Species Group Composition on the Flight Initiation Distances of Plains and Grevy's Zebras. Ethology 2016. [DOI: 10.1111/eth.12500] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Richard G. Coss
- Department of Psychology; University of California; Davis CA USA
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11
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Stone Tools: Evidence of Something in Between Culture and Cumulative Culture? THE NATURE OF CULTURE 2016. [DOI: 10.1007/978-94-017-7426-0_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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12
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Animal movements in the Kenya Rift and evidence for the earliest ambush hunting by hominins. Sci Rep 2015; 5:14011. [PMID: 26369499 PMCID: PMC4570197 DOI: 10.1038/srep14011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 07/27/2015] [Indexed: 11/08/2022] Open
Abstract
Animal movements in the Kenya Rift Valley today are influenced by a combination of topography and trace nutrient distribution. These patterns would have been the same in the past when hominins inhabited the area. We use this approach to create a landscape reconstruction of Olorgesailie, a key site in the East African Rift with abundant evidence of large-mammal butchery between ~1.2 and ~0.5 Ma BP. The site location in relation to limited animal routes through the area show that hominins were aware of animal movements and used the location for ambush hunting during the Lower to Middle Pleistocene. These features explain the importance of Olorgesailie as a preferred location of repeated hominin activity through multiple changes in climate and local environmental conditions, and provide insights into the cognitive and hunting abilities of Homo erectus while indicating that their activities at the site were aimed at hunting, rather than scavenging.
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Dirks PHGM, Berger LR, Roberts EM, Kramers JD, Hawks J, Randolph-Quinney PS, Elliott M, Musiba CM, Churchill SE, de Ruiter DJ, Schmid P, Backwell LR, Belyanin GA, Boshoff P, Hunter KL, Feuerriegel EM, Gurtov A, Harrison JDG, Hunter R, Kruger A, Morris H, Makhubela TV, Peixotto B, Tucker S. Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa. eLife 2015; 4. [PMID: 26354289 PMCID: PMC4559842 DOI: 10.7554/elife.09561] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/10/2015] [Indexed: 11/13/2022] Open
Abstract
We describe the physical context of the Dinaledi Chamber within the Rising Star cave, South Africa, which contains the fossils of Homo naledi. Approximately 1550 specimens of hominin remains have been recovered from at least 15 individuals, representing a small portion of the total fossil content. Macro-vertebrate fossils are exclusively H. naledi, and occur within clay-rich sediments derived from in situ weathering, and exogenous clay and silt, which entered the chamber through fractures that prevented passage of coarser-grained material. The chamber was always in the dark zone, and not accessible to non-hominins. Bone taphonomy indicates that hominin individuals reached the chamber complete, with disarticulation occurring during/after deposition. Hominins accumulated over time as older laminated mudstone units and sediment along the cave floor were eroded. Preliminary evidence is consistent with deliberate body disposal in a single location, by a hominin species other than Homo sapiens, at an as-yet unknown date. DOI:http://dx.doi.org/10.7554/eLife.09561.001 Modern humans, or Homo sapiens, are now the only living species in their genus. But as recently as 20,000 years ago there were other species that belonged to the genus Homo. Together with modern humans, these extinct human species, our immediate ancestors and their close relatives are collectively referred to as ‘hominins’. Now, Dirks et al. describe an unusual collection of hominin fossils that were found within the Dinaledi Chamber in the Rising Star cave system in South Africa. The fossils all belong to a newly discovered hominin species called Homo naledi, which is described in a related study by Berger et al. The unearthed fossils are the largest collection of hominin fossils from a single species ever to be discovered in Africa, and include the remains of at least 15 individuals and multiple examples of most of the bones in the skeleton. Dirks et al. explain that the assemblage from the Dinaledi Chamber is unusual because of the large number of fossils discovered so close together in a single chamber deep within the cave system. It is also unusual that no other large animal remains were found in the chamber, and that the bodies had not been damaged by scavengers or predators. The fossils were excavated from soft clay-rich sediments that had accumulated in the chamber over time; it also appears that the bodies were intact when they arrived in the chamber, and then started to decompose. Dirks et al. discuss a number of explanations as to how the remains came to rest in the Dinaledi Chamber, which range from whether Homo naledi lived in the caves to whether they were brought in by predators. Most of the evidence obtained so far is largely consistent with these bodies being deliberately disposed of in this single location by the same extinct hominin species. However, a number of other explanations cannot be completely ruled out and further investigation is now needed to uncover the series of events that resulted in this unique collection of hominin fossils. DOI:http://dx.doi.org/10.7554/eLife.09561.002
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Affiliation(s)
- Paul H G M Dirks
- Department of Earth and Oceans, James Cook University, Townsville, Australia
| | - Lee R Berger
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Eric M Roberts
- Department of Earth and Oceans, James Cook University, Townsville, Australia
| | - Jan D Kramers
- Department of Geology, University of Johannesburg, Johannesburg, South Africa
| | - John Hawks
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Patrick S Randolph-Quinney
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Marina Elliott
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Charles M Musiba
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Steven E Churchill
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Darryl J de Ruiter
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Peter Schmid
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Lucinda R Backwell
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Georgy A Belyanin
- Department of Geology, University of Johannesburg, Johannesburg, South Africa
| | - Pedro Boshoff
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - K Lindsay Hunter
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Elen M Feuerriegel
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Alia Gurtov
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - James du G Harrison
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Rick Hunter
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Ashley Kruger
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Hannah Morris
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Tebogo V Makhubela
- Department of Geology, University of Johannesburg, Johannesburg, South Africa
| | - Becca Peixotto
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Steven Tucker
- Evolutionary Studies Institute, National Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
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14
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Grove M, Burke A. Environmental variability and hominin dispersal. J Hum Evol 2015; 87:1-4. [PMID: 26341033 DOI: 10.1016/j.jhevol.2015.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 07/14/2015] [Indexed: 10/23/2022]
Affiliation(s)
- Matt Grove
- Archaeology, Classics and Egyptology, University of Liverpool, 12-14 Abercromby Square, Liverpool L69 7WZ, UK.
| | - Ariane Burke
- Departement d'Anthropologie, Université de Montreal, C.P. 6128, Succursale Centre-Ville, Montreal, QC, Canada
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Evolution and dispersal of the genus Homo: A landscape approach. J Hum Evol 2015; 87:48-65. [PMID: 26235482 DOI: 10.1016/j.jhevol.2015.07.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 07/05/2015] [Accepted: 07/09/2015] [Indexed: 02/07/2023]
Abstract
The notion of the physical landscape as an arena of ecological interaction and human evolution is a powerful one, but its implementation at larger geographical and temporal scales is hampered by the challenges of reconstructing physical landscape settings in the geologically active regions where the earliest evidence is concentrated. We argue that the inherently dynamic nature of these unstable landscapes has made them important agents of biological change, creating complex topographies capable of selecting for, stimulating, obstructing or accelerating the latent and emerging properties of the human evolutionary trajectory. We use this approach, drawing on the concepts and methods of active tectonics, to develop a new perspective on the origins and dispersal of the Homo genus. We show how complex topography provides an easy evolutionary pathway to full terrestrialisation in the African context, and would have further equipped members of the genus Homo with a suite of adaptive characteristics that facilitated wide-ranging dispersal across ecological and climatic boundaries into Europe and Asia by following pathways of complex topography. We compare this hypothesis with alternative explanations for hominin dispersal, and evaluate it by mapping the distribution of topographic features at varying scales, and comparing the distribution of early Homo sites with the resulting maps and with other environmental variables.
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Reynolds SC, Wilkinson DM, Marston CG, O'Regan HJ. The ‘mosaic habitat’ concept in human evolution: past and present. ACTA ACUST UNITED AC 2015. [DOI: 10.1080/0035919x.2015.1007490] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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17
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Stewart KM. Environmental change and hominin exploitation of C4-based resources in wetland/savanna mosaics. J Hum Evol 2014; 77:1-16. [DOI: 10.1016/j.jhevol.2014.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 03/05/2014] [Accepted: 10/06/2014] [Indexed: 10/24/2022]
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18
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Prassack KA. Landscape distribution and ecology of Plio-Pleistocene avifaunal communities from Lowermost Bed II, Olduvai Gorge, Tanzania. J Hum Evol 2014; 70:1-15. [PMID: 24650736 DOI: 10.1016/j.jhevol.2013.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 08/07/2013] [Accepted: 09/13/2013] [Indexed: 10/25/2022]
Abstract
Plio-Pleistocene avifaunal communities are used to reconstruct Lowermost Bed II landscapes at the early hominin site of Olduvai Gorge, Tanzania. These deposits are laterally extensive, have strong chronostratigraphic control, and were excavated using a landscape archaeological approach. Such factors allow for horizontal spatial-correlation of avian communities across the paleolandscape over a geologically short time frame (approximately 65,000 years). Lowermost Bed II avifaunal communities point to an extensive freshwater wetland system across the extent of paleo-Lake Olduvai's eastern margin.
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Affiliation(s)
- Kari A Prassack
- Center for Human Evolutionary Studies, Rutgers University, 131 George Street, New Brunswick, NJ 08901, USA.
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19
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Domínguez-Rodrigo M. Is the “Savanna Hypothesis” a Dead Concept for Explaining the Emergence of the Earliest Hominins? CURRENT ANTHROPOLOGY 2014. [DOI: 10.1086/674530] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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20
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Anemone R, Emerson C, Conroy G. Finding fossils in new ways: an artificial neural network approach to predicting the location of productive fossil localities. Evol Anthropol 2012; 20:169-80. [PMID: 22034235 DOI: 10.1002/evan.20324] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chance and serendipity have long played a role in the location of productive fossil localities by vertebrate paleontologists and paleoanthropologists. We offer an alternative approach, informed by methods borrowed from the geographic information sciences and using recent advances in computer science, to more efficiently predict where fossil localities might be found. Our model uses an artificial neural network (ANN) that is trained to recognize the spectral characteristics of known productive localities and other land cover classes, such as forest, wetlands, and scrubland, within a study area based on the analysis of remotely sensed (RS) imagery. Using these spectral signatures, the model then classifies other pixels throughout the study area. The results of the neural network classification can be examined and further manipulated within a geographic information systems (GIS) software package. While we have developed and tested this model on fossil mammal localities in deposits of Paleocene and Eocene age in the Great Divide Basin of southwestern Wyoming, a similar analytical approach can be easily applied to fossil-bearing sedimentary deposits of any age in any part of the world. We suggest that new analytical tools and methods of the geographic sciences, including remote sensing and geographic information systems, are poised to greatly enrich paleoanthropological investigations, and that these new methods should be embraced by field workers in the search for, and geospatial analysis of, fossil primates and hominins.
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Nonlinear detection of paleoclimate-variability transitions possibly related to human evolution. Proc Natl Acad Sci U S A 2011; 108:20422-7. [PMID: 22143765 DOI: 10.1073/pnas.1117052108] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Potential paleoclimatic driving mechanisms acting on human evolution present an open problem of cross-disciplinary scientific interest. The analysis of paleoclimate archives encoding the environmental variability in East Africa during the past 5 Ma has triggered an ongoing debate about possible candidate processes and evolutionary mechanisms. In this work, we apply a nonlinear statistical technique, recurrence network analysis, to three distinct marine records of terrigenous dust flux. Our method enables us to identify three epochs with transitions between qualitatively different types of environmental variability in North and East Africa during the (i) Middle Pliocene (3.35-3.15 Ma B.P.), (ii) Early Pleistocene (2.25-1.6 Ma B.P.), and (iii) Middle Pleistocene (1.1-0.7 Ma B.P.). A deeper examination of these transition periods reveals potential climatic drivers, including (i) large-scale changes in ocean currents due to a spatial shift of the Indonesian throughflow in combination with an intensification of Northern Hemisphere glaciation, (ii) a global reorganization of the atmospheric Walker circulation induced in the tropical Pacific and Indian Ocean, and (iii) shifts in the dominating temporal variability pattern of glacial activity during the Middle Pleistocene, respectively. A reexamination of the available fossil record demonstrates statistically significant coincidences between the detected transition periods and major steps in hominin evolution. This result suggests that the observed shifts between more regular and more erratic environmental variability may have acted as a trigger for rapid change in the development of humankind in Africa.
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