Search results
Results from the WOW.Com Content Network
The southern route dispersal is primarily linked to the Initial Upper Paleolithic expansion of modern humans and "ascribed to a population movement with uniform genetic features and material culture" (Ancient East Eurasians), which was the major source for the peopling of the Asia–Pacific region.
Beringia sea levels (blues) and land elevations (browns) measured in metres from 21,000 years ago to present. Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72° north latitude in the Chukchi Sea; and on the south by the tip of the Kamchatka Peninsula. [1]
Research shows that a distance of 50 meters is an important constraint on the effective dispersal and gene flow for fairy shrimp. [11] Isolation by distance also occurs as a result of competition between species: spatial segregation may be due to the negative impact of a species' activity on another one. [12]
Until the early 1980s, early humans were thought to have been restricted to the African continent in the Early Pleistocene, or until about 0.8 Ma; Hominin migrations outside East Africa were apparently rare in the Early Pleistocene, leaving a fragmentary record of events. [4] [5]
Map of early human migrations based on the Out of Africa theory; figures are in thousands of years ago (kya). [1]The peopling of the Americas began when Paleolithic hunter-gatherers (Paleo-Indians) entered North America from the North Asian Mammoth steppe via the Beringia land bridge, which had formed between northeastern Siberia and western Alaska due to the lowering of sea level during the ...
Generally speaking, however, the dispersal and subsequent explosive adaptive radiation of sigmodontine rodents throughout South America (leading to over 80 currently recognized genera) was vastly more successful (both spatially and by number of species) than any northward migration of South American mammals. Other examples of North American ...
In biogeography, geodispersal is the erosion of barriers to gene flow and biological dispersal (Lieberman, 2005.; [1] Albert and Crampton, 2010. [2]). Geodispersal differs from vicariance, which reduces gene flow through the creation of geographic barriers. [3]
Like during the Triassic and Jurassic, Rhode Island's sediments were being eroded away rather than deposited during the ensuing Paleogene and Neogene periods of the Cenozoic era, leaving another gap in the state's geologic and fossil record. More recently, during the Pleistocene, Rhode Island was scoured by glaciers. [2]