نتایج جستجو برای: eurasia
تعداد نتایج: 2946 فیلتر نتایج به سال:
The northern latitudes have warmed by about 0.8 C since the early 1970s, but not all areas have warmed equally. Eurasia shows an overall warming trend, while North America exhibits warming at a lower rate and even a slight cooling trend during the last 50 years in the Eastern USA. We analyzed a recently developed satellite normalized di erence vegetation index (NDVI) data set (July 1981 to Dece...
[1] Africa-North America-Eurasia plate circuit rotations, combined with Red Sea rotations and new estimates of crustal shortening in Iran define the Cenozoic history of the Neotethyan ocean between Arabia and Eurasia. The new constraints indicate that Arabia-Eurasia convergence has been fairly constant at 2 to 3 cm/yr since 56 Ma with slowing of Africa-Eurasia motion to <1 cm/yr near 25 Ma, coe...
The geographic distribution of genetic variation reflects trends in past population migrations and can be used to make inferences about these migrations. It has been proposed that the east-west orientation of the Eurasian landmass facilitated the rapid spread of ancient technological innovations across Eurasia, while the north-south orientation of the Americas led to a slower diffusion of techn...
Engelswies is an early Miocene vertebrate locality in southern Germany with a rich assemblage of terrestrial mammals, invertebrates and fossil plants. It is dated to 16.5-17.0 Ma based on magnetostratigraphy, biostratigraphy and lithostratigraphy, and includes among the faunal remains a hominoid upper molar fragment, the oldest hominoid so far identified from Europe. The evidence from Engelswie...
Although there is a general consensus on African origin of early modern humans, there is disagreement about how and when they dispersed to Eurasia. This paper reviews genetic and Middle Stone Age/Middle Paleolithic archaeological literature from northeast Africa, Arabia, and the Levant to assess the timing and geographic backgrounds of Upper Pleistocene human colonization of Eurasia. At the cen...
Recent hunter-gatherers display much uniformity in the division of labor along the lines of gender and age. The complementary economic roles for men and women typical of ethnographically documented hunter-gatherers did not appear in Eurasia until the beginning of the Upper Paleolithic. The rich archaeological record of Middle Paleolithic cultures in Eurasia suggests that earlier hominins pursue...
Resumen.—Muchas especies de playeros tienen distribuciones amplias que incluyen continentes diferentes. Debido a que los playeros son excelentes voladores y tienen la capacidad de migrar largas distancias, muchas veces no está claro si existen barreras reproductivas entre poblaciones o subespecies de diferentes continentes. Charadrius alexandrinus es una especie cosmopolita. Hace mucho tiempo s...
Polyploid formation is a major mode of sympatric speciation in flowering plants. Unlike other speciation processes, polyploidization is often assumed to confer instant reproductive isolation. Shared polymorphism across ploidy levels has therefore often been attributed to multiple polyploid origins, whereas the alternative hypothesis of introgressive hybridization has rarely been rigorously test...
[1] Reconstructions of the relative positions of the India and Eurasia plates, using recently revised histories of movement between India and Somalia and between North America and Eurasia and of the opening of the East African Rift, show that India’s convergence rate with Eurasia slowed by more than 40% between 20 and 10 Ma. Much evidence suggests that beginning in that interval, the Tibetan Pl...
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