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1.
Our knowledge concerning stature in earlyHomo is scanty. In this paper, based on comparison with the fossil femur KNM-ER 999, an estimate of 482 mm femur length is derived for KNM-ER 736, the latter dating from the Lower Pleistocene. From comparison with other fossil and modern femora, KNM-ER 736 appears to be the longest hominid femur so far recovered from a site of Early Pleistocene age. Moreover, the estimated femur length is higher than the published mean values of most modern populations. Provided that trunk and head proportions were not radically different from modernH. sapiens, the finding would suggest that a stature similar to that of modern man was already reached by East AfricanHomo as early as about 1.6 Myr before present.  相似文献   

2.
Abstract. 1. Comparison of dominant wind directions with seasonal redistribution of Spodoptera exempta caterpillar outbreaks in East Africa provides further circumstantial evidence to support the hypothesis of downwind migration by adult moths.
2. Calculated backward and forward tracks for sixty-nine nights during the 1973–74 and 1974–75 seasons, when there were sudden increases in numbers of moths caught at six light traps, illustrate the variability of downwind movement due to the effects of temporary atmospheric disturbances.
3. Comparison of calculated tracks with known outbreaks before and after the nights of increased moth catch suggests that some outbreaks are derived from unreported sources, especially eariy in the season, and it is therefore unwise to link new outbreaks only with known earlier ones.  相似文献   

3.
We present an overview of archaeobotanical Carthamus spp. finds from Neolithic to medieval sites in the Near East and adjacent areas. A particular focus is put on the cultivated form of the genus. Safflower appears first in a number of early Bronze Age (3000 b.c.) sites in northern and central Syria. From there it apparently spread to Egypt, the Aegean and south-eastern Europe. The Near Eastern Bronze Age evidence shows a striking exclusiveness in the distribution patterns of safflower and flax, with flax being restricted to Levantine and Iranian sites. This may reflect the contrasting ecological requirements of the two crops, with safflower being well adapted to drought and salinity and thus to arid conditions. At the same time the geographically complementary evidence may indicate a similar use of the two crops and most probably suggests that the safflower was also used for oil almost from the beginning of its cultivation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

4.
Abstract The aim of this study was to characterize the short-term land-cover change processes that were detected in Eastern Africa, based on a set of change metrics that allow for the quantification of interannual changes in vegetation productivity, changes in vegetation phenology and a combination of both. We tested to what extent land use, fire activity and livestock grazing modified the vegetation response to short-term rainfall variability in East Africa and how this is reflected in change metrics derived from MODerate Imaging Spectrometer (MODIS) time series of remote sensing data. We used a hierarchical approach to disentangle the contribution of human activities and climate variability to the patterns of short-term vegetation change in East Africa at different levels of organization. Our results clearly show that land use significantly influences the vegetation response to rainfall variability as measured by time series of MODIS data. Areas with different types of land use react in a different way to interannual climate variability, leading to different values of the change indices depending on the land use type. The impact of land use is more reflected in interannual variability of vegetation productivity and overall change in the vegetation, whereas changes in phenology are mainly driven by climate variability and affect most vegetation types in similar ways. Our multilevel approach led to improved models and clearly demonstrated that climate influence plays at a different scale than land use, fire and herbivore grazing. It helped us to understand dynamics within and between biomes in the study area and investigate the relative importance of different factors influencing short-term variability in change indices at different scales.  相似文献   

5.
The Early Stone Age sites of Gadeb (Ethiopian South-East Plateau) were excavated under the direction of Desmond Clark in the 1970s. Dated to between 1.45 and 0.7 Ma, Gadeb proved that humans had already occupied high altitude areas in the Lower Pleistocene. Despite the importance of the Gadeb sites, their lithic assemblages were never published in detail, and no review of the stone tools has ever been reported since the original 1970s study. This paper updates the information available on Gadeb by presenting a systematic review of the lithic technology of several assemblages. The objectives are to evaluate the technological skills of Gadeb knappers and to contextualize them into the current discussion of the origins of the Acheulean and its possible coexistence with the so-called Developed Oldowan in East Africa.  相似文献   

6.
Twenty‐one years ago, a landmark exploration of mitochondrial DNA diversity popularized the idea of a recent African origin for all living humans. 1 The ancestral African population was estimated to have existed 200 ka (thousands of years ago) plus or minus a few tens of thousands of years. A corollary was that at some later date the fully modern African descendants of that population expanded to swamp or replace the Neanderthals and other nonmodern Eurasians. The basic concept soon became known as “Out of Africa,” after the Academy Award winning film (1985) that took its title, in turn, from Isak Dinesen's classic autobiography (1937). Many subsequent genetic analyses, including those of Ingman and coworkers 2 and Underhill and coworkers, 3 have reaffirmed the fundamental Out of Africa model. The fossil and archeological records also support it strongly. The fossil record implies that anatomically modern or near‐modern humans were present in Africa by 150 ka; the fossil and archeological records together indicate that modern Africans expanded to Eurasia beginning about 50 ka.  相似文献   

7.
Human societies maintain between-group variation despite mixing of people and ideas. In order for variation to remain, migrants or their children must preferentially adopt local norms, customs, and beliefs. Yet the details of how cultural variation is maintained, despite mixing, remain unknown. This article addresses this problem by using a simple model of the evolution of cultural learning to interpret the results of a study of cultural variation in a small region of East Africa. I argue that the manner in which migrants of two diverse regions adapt to local beliefs and behavior depends on the costs and accuracy of learning in each domain. Observational studies are never definitive tests of any hypothesis, but these results suggest that conclusions about the significance of cultural learning for understanding individual attitudes and behavior depend strongly upon the domain of investigation.  相似文献   

8.
This article focuses on the life history of a single street boy in northwestern Tanzania, whom I name Juma. I suggest that Juma's experiences and the life trajectory of himself and of significant individuals around him (particularly his mother) were structured by everyday violence. I describe everyday violence in terms of a conjuncture between macrostructural forces in East Africa (including a history of failed development schemes and the contemporary political economy of neoliberalism) and the lived experience of individuals as they negotiate local, contextual factors (including land-tenure practices, the power dynamics between immediate and extended kin, life on the streets, and constructions of gender and sexuality). I suggest that AIDS and its many impacts on Juma's life course can only be understood in a broader context of everyday violence. From this basis, I draw several general conclusions regarding AIDS prevention and intervention strategies.  相似文献   

9.
More than a third of the European pool of human mitochondrial DNA (mtDNA) is fragmented into a number of subclades of haplogroup (hg) H, the most frequent hg throughout western Eurasia. Although there has been considerable recent progress in studying mitochondrial genome variation in Europe at the complete sequence resolution, little data of comparable resolution is so far available for regions like the Caucasus and the Near and Middle East-areas where most of European genetic lineages, including hg H, have likely emerged. This gap in our knowledge causes a serious hindrance for progress in understanding the demographic prehistory of Europe and western Eurasia in general. Here we describe the phylogeography of hg H in the populations of the Near East and the Caucasus. We have analyzed 545 samples of hg H at high resolution, including 15 novel complete mtDNA sequences. As in Europe, most of the present-day Near Eastern-Caucasus area variants of hg H started to expand after the last glacial maximum (LGM) and presumably before the Holocene. Yet importantly, several hg H subclades in Near East and Southern Caucasus region coalesce to the pre-LGM period. Furthermore, irrespective of their common origin, significant differences between the distribution of hg H sub-hgs in Europe and in the Near East and South Caucasus imply limited post-LGM maternal gene flow between these regions. In a contrast, the North Caucasus mitochondrial gene pool has received an influx of hg H variants, arriving from the Ponto-Caspian/East European area.  相似文献   

10.
11.
The phenotypic consequences in the house mouse (Mus musculus domesticus) of the transition from an ordinary field-dwelling rodent to a species that is dependent on human populations was studied by investigating the morphometric variation of non-commensal populations of M. m. domesticus from Syria, Jordan, SW Iran, and Libya and comparing them with that of conspecific commensal populations from Eastern Turkey, Greece, and Bulgaria. Commensal populations of M. musculus musculus from the Czech Republic were used as an outgroup. About 849 adult specimens of M. musculus were analysed by multivariate procedures based on standard molar, skull and body measurements. As expected, there was considerable variation among the studied populations and a good correspondence between morphometric and geographic distances. The resulting morphometric tree was consistent with the hypothesis that the original radiation of M. m. domesticus took place somewhere in the Near East. Commensal populations of M. m. domesticus form a single derived branch. Specimens originating from four different sites in eastern Syria showed the greatest similarity to one another and possessed relatively bigger molars than the other studied populations. Commensal populations were characterised by longer tails when compared to non-commensal populations, which suggests an adaptation for living in a more three-dimensionally heterogeneous environment for commensal populations.  相似文献   

12.
In this article we examine the natural habitats and distribution of the six wild cereals: Triticum urartu (wild urartu wheat), T. boeoticum aegilopoides (single-grained wild einkorn), T. boeoticum thaoudar (two-grained wild einkorn), T. dicoccoides (wild emmer wheat), Secale spp. (wild ryes) and Hordeum spontaneum (wild barley). A comparison of late Pleistocene/early Holocene archaeobotanical assemblages in the Near East with present-day distributions of wild cereals shows a good correlation. The regional variation in the archaeobotanical cereal assemblages and the ensuing domestication provide evidence that different cereal species were domesticated independently in different areas. Some sites were not situated near wild cereal habitats and a few were located outside the limits of distribution, even accounting for moister climatic conditions. I argue here that current models which try to explain the shift to farming have tended to over-emphasize the effect of the Younger Dryas climatic change. First, it would have had only a minor effect on cereal availability. Secondly, agriculture appears to have been established after the Younger Dryas. Thirdly, there is no evidence for a single centre of origin; agriculture arose in widely separated geographic and climatic regions. And fourthly, agriculture depends on stable climatic conditions which were not established until after the Younger Dryas.  相似文献   

13.
 The morphological variation of the Bersama abyssinica complex in East Africa is analysed. A wide range of characters was examined both on specimens collected for this study and on a selection of type material. The character distribution of each character was examined individually. The ratios of some of the characters were calculated, and selected characters were plotted in pairwise combinations. Non-metric multidimensional scaling and principal component analysis were employed in the multivariate analyses. On the basis of the patterns observed in the numerical analyses as well as those in the field, a new combination, Bersama abyssinica Fresen. ssp. rosea (Hoyle) Mikkelsen is proposed. The presence of the two flower types described by White: (a) male flowers, with long stamens and short gynoecium and (b) female flowers, with short, abortive stamens and long gynoecium is confirmed, but found to be taxonomically insignificant. Received May 12, 2000 Accepted February 13, 2001  相似文献   

14.
Optically stimulated luminescence (OSL) measurements are reported for both single aliquots (of two different sizes) and single grains of quartz from deposits within Blombos Cave. Ages have been obtained for six sediments from the Middle Stone Age (MSA) occupation levels and for two sterile sands, one underlying the archaeological sediment and one overlying the Later Stone Age occupation levels. The ages for the archaeological sediments were obtained from single-grain measurements that enabled unrepresentative grains to be rejected. The MSA occupation levels have ages that, within error limits, are in stratigraphic order and fall between the OSL age for the oldest dune sand (143.2+/-5.5 ka) and a previously published OSL age for the sterile sand ( approximately 70 ka) that separates the Middle and Later Stone Age deposits. The earliest MSA archaeological phase, M3, from where fragments of ochre were found as well as human teeth, is dated to 98.9+/-4.5 ka, coinciding with the sea-level high of oxygen isotope substage 5c. The cave then appears to be unoccupied until oxygen isotope substage 5a on the basis of four OSL ages for archaeological phase M2, ranging from 84.6+/-5.8 to 76.8+/-3.1 ka; these levels contained large hearths and bone tools. An age of 72.7+/-3.1 ka was obtained for the final MSA archaeological phase, M1, from which deliberately engraved ochre and shell beads were recovered along with bifacial stone points. We conclude that the periods of occupation were determined by changes in sea level, with abundant sources of seafood available in times of high sea level and with the cave being closed by the accumulation of large dunes during periods of low sea level, such as during oxygen isotope stages 4 and 6.  相似文献   

15.
Since the discovery of the human remains from the Upper Cave of Zhoukoudian in the 1930s there has been speculation over their affinities. In particular, the degree to which the three adult crania exhibit recent East Asian morphology, as well as their degree of within-group variability, has long been debated. Several early researchers described a resemblance to East Asian populations, but these findings have been for the most part rejected by more recent metric and non-metric analyses. Nevertheless, the Upper Cave specimens have not been classified conclusively into any recent modern human population to which they have been compared, and classification results differ for each cranium. Here, the question of the affinities of Upper Cave 101 and 103, the two better-preserved crania, is examined from the perspective of the Late Pleistocene human fossil record using the methodology of 3-D geometric morphometrics. The degree of morphological variation between the two specimens is also evaluated within the context of recent population variability. Neurocranial and facial morphology are analyzed separately so as to maximize comparative samples. Results show a morphological resemblance of the Upper Cave material to Upper Paleolithic Europeans. It is proposed that the Upper Cave specimens retain important aspects of modern human ancestral morphology, and possibly share a recent common ancestral population with Upper Paleolithic Europeans, in accordance with the Single Origin model of modern human origins.  相似文献   

16.
The fish resources of Lake St Lucia, the largest estuary on the eastcoast of Africa, present resource managers of the Natal Parks Board with acommon property resource (CPR) problem. Problems associated with illegal gillnetting by local people from three tribal areas, prompted the introduction of asystem of legal, subsistence netting. This paper reviews the legal fisheries inthese three areas from 1995 to 1997, and examines existing organizationalarrangements, suggesting reasons why the three fisheries show differences infunctioning. By employing concepts from CPRs theory, elements of anorganizational design for fisheries management involving local users and theconservation organization staff are proposed.  相似文献   

17.
Sweet potato feathery mottle virus (SPFMV, genus Potyvirus) is globally the most common pathogen of cultivated sweet potatoes (Ipomoea batatas; Convolvulaceae). Although more than 150 SPFMV isolates have been sequence‐characterized from cultivated sweet potatos across the world, little is known about SPFMV isolates from wild hosts and the evolutionary forces shaping SPFMV population structures. In this study, 46 SPFMV isolates from 14 wild species of genera Ipomoea, Hewittia and Lepistemon (barcoded for the matK gene in this study) and 13 isolates from cultivated sweet potatoes were partially sequenced. Wild plants were infected with the EA, C or O strain, or co‐infected with the EA and C strains of SPFMV. In East Africa, SPFMV populations in wild species and sweet potato were genetically undifferentiated, suggesting inter‐host transmission of SPFMV. Globally, spatial diversification of the 178 isolates analysed was observed, strain EA being largely geographically restricted to East Africa. Recombination was frequently detected in the 6K2‐VPg‐NIaPro region of the EA strain, demonstrating a recombination ‘hotspot’. Recombination between strains EA and C was rare, despite their frequent co‐infections in wild plants, suggesting purifying selection against strain EA/C recombinants. Positive selection was predicted on 17 amino acids distributed over the entire coat protein in the globally distributed strain C, as compared to only four amino acids in the coat protein N‐terminus of the EA strain. This selection implies a more recent introduction of the C strain and a higher adaptation of the EA strain to the local ecosystem. Thus, East Africa appears as a hotspot for evolution and diversification of SPFMV.  相似文献   

18.
Integrated assessment seeks to combine models of the ecological as well as the social system to allow different scenarios to be tested in terms of their likely impacts on ecological functioning and household well-being. We outline such work undertaken in four case studies in East and southern Africa: pastoralist communities in northern Tanzania, agro-pastoralists in southern Kenya, communal and commercial ranchers in South Africa, and mixed crop-livestock farmers in western Kenya. Results from these case studies are synthesised to test the hypothesis that households’ capacity to adapt in the face of increasing external stresses is governed by flexibility in livelihood options. The results support this hypothesis. There is considerable variation in how households in these places cope with external stresses. Options include intensification, diversification, and increasing off-farm economic activities, and these depend on household objectives and attitudes as well as on access to natural resources, inputs and output markets. The results also indicate that generally it is the poorer households that can gain the most from implementing such options for coping and managing risk. Quantifying likely household and ecosystem impacts of different options is a crucial step in targeting appropriate technology, policy and adaptation interventions in the face of considerable system changes. We conclude with some research needs to improve integrated assessment tools that may allow us to represent more realistically the highly complex decision-making milieu of householders in sub-Saharan Africa who are dependent on ecosystem goods and services for a large part of their livelihoods.  相似文献   

19.
Gazza squamiventralis sp. nov. is described as the fifth species of the genus, based on the holotype and eight paratypes, 42–96 mm in standard length, collected along the east coast of Africa, from Kenya to Mozambique. The species is similar to other congeners in general appearance, differing clearly from them in having the ventrolateral surface of the body scaled anterior to a line from the pectoral fin base to the pelvic fin origin (vs naked) and a smooth supraorbital ridge (vs finely serrated). Additionally, the species differs from G. dentex, G. rhombea, and G. achlamys in having the dorsolateral surface of the body scaled anterior to a vertical through the tip of the posterior branch of the supratemporal canal (vs corresponding region naked), and from G. minuta in having the first dorsal fin pterygiophore narrowly expanded anteriorly, with a concave margin (vs broadly expanded, with a convex or linear margin), and a short antrorse extension of the first anal fin pterygiophore (vs long). A key to the five species of the genus Gazza is provided. Received: May 30, 2000 / Revised: September 16, 2000 / Accepted: January 16, 2001  相似文献   

20.
Current evidence suggests that many of the major events in hominin evolution occurred in East Africa. Hence, over the past two decades, there has been intensive work undertaken to understand African palaeoclimate and tectonics in order to put together a coherent picture of how the environment of Africa has varied over the past 10 Myr. A new consensus is emerging that suggests the unusual geology and climate of East Africa created a complex, environmentally very variable setting. This new understanding of East African climate has led to the pulsed climate variability hypothesis that suggests the long-term drying trend in East Africa was punctuated by episodes of short alternating periods of extreme humidity and aridity which may have driven hominin speciation, encephalization and dispersals out of Africa. This hypothesis is unique as it provides a conceptual framework within which other evolutionary theories can be examined: first, at macro-scale comparing phylogenetic gradualism and punctuated equilibrium; second, at a more focused level of human evolution comparing allopatric speciation, aridity hypothesis, turnover pulse hypothesis, variability selection hypothesis, Red Queen hypothesis and sympatric speciation based on sexual selection. It is proposed that each one of these mechanisms may have been acting on hominins during these short periods of climate variability, which then produce a range of different traits that led to the emergence of new species. In the case of Homo erectus (sensu lato), it is not just brain size that changes but life history (shortened inter-birth intervals, delayed development), body size and dimorphism, shoulder morphology to allow thrown projectiles, adaptation to long-distance running, ecological flexibility and social behaviour. The future of evolutionary research should be to create evidence-based meta-narratives, which encompass multiple mechanisms that select for different traits leading ultimately to speciation.  相似文献   

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