نتایج جستجو برای: pleistocene
تعداد نتایج: 8977 فیلتر نتایج به سال:
Climatic oscillations during the Pleistocene have greatly influenced the distribution and connectivity of many organisms, leading to extinctions but also generating biodiversity. While the effects of such changes have been extensively studied in the terrestrial environment, studies focusing on the marine realm are still scarce. Here we used sequence data from one mitochondrial and five nuclear ...
Pleistocene diversity was much higher than today, for example there were three distinct wolf morphotypes (dire, gray, Beringian) in North America versus one today (gray). Previous fossil evidence suggested that these three groups overlapped ecologically, but split the landscape geographically. The Natural Trap Cave (NTC) fossil site in Wyoming, USA is an ideally placed late Pleistocene site to ...
The Southern Levant is a pivotal area for the study of hominin paleoecology during the Lower Paleolithic, because of its location on the out-of-Africa dispersal route and its significant ecological diversity. Important information has been gained by archaeofaunal studies, which usually reveal that exploitation of diverse Mediterranean environments with woodlands, marshes and lake margins, repre...
The Mediterranean basin is an area of high diversity and endemicity, but the age and origin of its fauna are still largely unknown. Here we use species-level phylogenies based on approximately 1300 base pairs of the genes 16S rRNA and cytochrome oxidase I to establish the relationships of 27 of the 34 endemic Iberian species of diving beetles in the family Dytiscidae, and to investigate their l...
The sheepshead minnow, Cyprinodon variegatus, is a widespread fish species that typically inhabits coastal tidal marsh and mangrove swamp environments, ranging from Cape Cod, Massaschusetts to northern Mexico and into the Caribbean. This wide range crosses several biogeographic boundaries which are coincident with genetic structuring within numerous species originating in the Pleistocene. In ad...
Research investigating the geographical context of speciation has primarily focused on abiotic factors such as the role of Pleistocene glacial cycles, or geotectonic events. Few study systems allow a direct comparison of how biological differences, such as dispersal behaviour, affect population genetic structure of organisms that were subdivided during the Pleistocene. Mormon crickets exist in ...
Molecular phylogeography suggests that Micromys minutus, the sole extant species of the genus, colonized its extensive range quite recently, during the Late Pleistocene-Holocene period. Rich Pliocene and Pleistocene fossil records both from Europe and China suggest rather continuous and gradual in situ phenotype rearrangements from the Pliocene to the Recent periods. To elucidate the discrepanc...
The lengths of fossil leaves of Nothofagus cunninghamii, and of closely related fossil species from sediments older than the Middle Pleistocene showed greater variation than fossil leaves from younger sediments and extant leaves from modern sediment samples and forest floor litter. Leaf sizes of samples of the other two extant evergreen species of Nothofagus subgenus Lophozonia, N. moorei and N...
While the genetic impact of Pleistocene climate change on temperate species has been well characterized, especially in Europe and North America, an effect on the diversification of species on oceanic islands has been less well studied. This is perhaps a surprising observation given the traditional and continuing contribution of island species (e.g. Darwin's finches, Partula snails, Lord Howe Is...
In North America during the terminal Pleistocene (ca 15,000–10,000BP), patterns of geographical variability in mammal community richness differed from those observed here today. This paper presents analyses of paleontological and archaeological faunal data from throughout the continental US, and these analyses control for factors that might confound paleontological measurement of past community...
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