Cenozoic History of the Bering Land Bridge: The seaway between the Pacific and Arctic basins has often been a land route between Siberia and Alaska

Science ◽  
1959 ◽  
Vol 129 (3362) ◽  
pp. 1519-1528 ◽  
Author(s):  
D. M. Hopkins
Keyword(s):  
Land Bridge ◽  
Bering Land Bridge ◽  
The Pacific ◽  
History Of

scholarly journals Plastome Phylogenomics and Historical Biogeography of Aquatic Plant Genus Hydrocharis (Hydrocharitaceae)

2021 ◽  
Author(s):  
Zhi-Zhong Li ◽  
Samuli Lehtonen ◽  
Andrew W. Gichira ◽  
Karina Martins ◽  
Efremov Andrey ◽  
...  
Keyword(s):  
Aquatic Plant ◽  
Genome Structure ◽  
Central Africa ◽  
Taxonomic Status ◽  
Land Bridge ◽  
African Species ◽  
Repeat Sequences ◽  
Bering Land Bridge ◽  
History Of ◽  
Phylogenomic Analyses

Abstract Background Hydrocharis L. and Limnobium Rich. are small aquatic genera, including three and two species, respectively. The taxonomic status, phylogenetic relationships and biogeographical history of these genera have remained unclear, owing to the lack of Central African endemic H. chevalieri from all previous studies. We sequenced and assembled plastomes of all three Hydrocharis species and Limnobium laevigatum to explore the phylogenetic and biogeographical history of these aquatic plants. Results All four newly generated plastomes were conserved in genome structure, gene content, and gene order. However, they differed in size, the number of repeat sequences, and inverted repeat borders. Our phylogenomic analyses recovered non-monophyletic Hydrocharis. African species H. chevalieri was fully supported as sister to the rest of the species, and L. laevigatum was nested in Hydrocharis as a sister to H. dubia. Hydrocharis-Limnobium initially diverged from the remaining genera at ca. 53.3 Ma, then began to diversify at ca. 30.9 Ma. The biogeographic analysis suggested that Hydrocharis probably originated in Europe and Central Africa. Conclusion Based on the phylogenetic results, morphological similarity and small size of the genera, the most reasonable taxonomic solution to the non-monophyly of Hydrocharis is to treat Limnobium as its synonym. The African endemic H. chevalieri is fully supported as a sister to the remaining species. Hydrocharis mainly diversified in the Miocene, during which rapid climate change may have contributed to the speciation and extinctions. The American species of former Limnobium probably dispersed to America through the Bering Land Bridge during the Miocene.

scholarly journals Setting the Stage: The Late Pleistocene Colonization of North America

Quaternary ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
Michael O’Brien
Keyword(s):  
North America ◽  
Late Pleistocene ◽  
New World ◽  
Pacific Coast ◽  
Ice Sheets ◽  
Land Bridge ◽  
Projectile Points ◽  
Bering Land Bridge ◽  
The Pacific ◽  
Northern Half

The timing of human entrance into North America has been a topic of debate that dates back to the late 19th century. Central to the modern discussion is not whether late Pleistocene-age populations were present on the continent, but the timing of their arrival. Key to the debate is the age of tools—bone rods, large prismatic stone blades, and bifacially chipped and fluted stone weapon tips—often found associated with the remains of late Pleistocene fauna. For decades, it was assumed that this techno-complex—termed “Clovis”—was left by the first humans in North America, who, by 11,000–12,000 years ago, made their way eastward across the Bering Land Bridge, or Beringia, and then turned south through a corridor that ran between the Cordilleran and Laurentide ice sheets, which blanketed the northern half of the continent. That scenario has been challenged by more-recent archaeological and archaeogenetic data that suggest populations entered North America as much as 15,300–14,300 years ago and moved south along the Pacific Coast and/or through the ice-free corridor, which apparently was open several thousand years earlier than initially thought. Evidence indicates that Clovis might date as early as 13,400 years ago, which means that it was not the first technology in North America. Given the lack of fluted projectile points in the Old World, it appears certain that the Clovis techno-complex, or at least major components of it, emerged in the New World.

The enigmatic history of the European, Asian and American plethodontid salamanders

2013 ◽  
Vol 34 (3) ◽  
pp. 323-336 ◽  
Author(s):  
David B. Wake
Keyword(s):  
North America ◽  
Close Relative ◽  
Land Bridge ◽  
Time Estimates ◽  
Bering Land Bridge ◽  
Plethodontid Salamanders ◽  
New Information ◽  
History Of ◽  
Published Research ◽  
American Clade

Recently published research addressing the question of relationships and biogeography of European plethodontid salamanders has refined time estimates for divergence from American relatives. The recently discovered Korean plethodontid Karsenia is either the sister-taxon of Hydromantes (which has members in Europe and California), or a close relative and co-member of a larger clade that originated in western North America, not eastern North America as formerly thought. The new information strengthens the biogeographical hypothesis that Hydromantes entered Eurasia via the Bering Land Bridge. Arguments are made favoring the placement of European and American relatives in a genus Hydromantes, with an American clade (subgenus Hydromantes) and a European clade (subgenera Atylodes and Speleomantes).

Late Quaternary vegetation and climate history of the central Bering land bridge from St. Michael Island, western Alaska

2003 ◽  
Vol 60 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Thomas A. Ager
Keyword(s):  
Boreal Forests ◽  
Vegetation Change ◽  
Late Quaternary ◽  
Land Bridge ◽  
Climate History ◽  
Middle Holocene ◽  
Bering Land Bridge ◽  
Dwarf Birch ◽  
History Of ◽  
Vegetation And Climate

AbstractPollen analysis of a sediment core from Zagoskin Lake on St. Michael Island, northeast Bering Sea, provides a history of vegetation and climate for the central Bering land bridge and adjacent western Alaska for the past ≥30,000 14C yr B.P. During the late middle Wisconsin interstadial (≥30,000–26,000 14C yr B.P.) vegetation was dominated by graminoid-herb tundra with willows (Salix) and minor dwarf birch (Betula nana) and Ericales. During the late Wisconsin glacial interval (26,000–15,000 14C yr B.P.) vegetation was graminoid-herb tundra with willows, but with fewer dwarf birch and Ericales, and more herb types associated with dry habitats and disturbed soils. Grasses (Poaceae) dominated during the peak of this glacial interval. Graminoid-herb tundra suggests that central Beringia had a cold, arid climate from ≥30,000 to 15,000 14C yr B.P. Between 15,000 and 13,000 14C yr B.P., birch shrub-Ericales-sedge-moss tundra began to spread rapidly across the land bridge and Alaska. This major vegetation change suggests moister, warmer summer climates and deeper winter snows. A brief invasion of Populus (poplar, aspen) occurred ca.11,000–9500 14C yr B.P., overlapping with the Younger Dryas interval of dry, cooler(?) climate. During the latest Wisconsin to middle Holocene the Bering land bridge was flooded by rising seas. Alder shrubs (Alnus crispa) colonized the St. Michael Island area ca. 8000 14C yr B.P. Boreal forests dominated by spruce (Picea) spread from interior Alaska into the eastern Norton Sound area in middle Holocene time, but have not spread as far west as St. Michael Island.

Quaternary Correlations across Bering Strait: Recent Soviet and American studies cast new light on the history of the Bering land bridge

Science ◽  
1965 ◽  
Vol 147 (3662) ◽  
pp. 1107-1114 ◽  
Author(s):  
D. M. Hopkins ◽  
F. S. MacNeil ◽  
R. L. Merklin ◽  
O. M. Petrov
Keyword(s):  
American Studies ◽  
Bering Strait ◽  
Land Bridge ◽  
Bering Land Bridge ◽  
History Of

scholarly journals Return to Beringia: parasites reveal cryptic biogeographic history of North American pikas

2011 ◽  
Vol 279 (1727) ◽  
pp. 371-378 ◽  
Author(s):  
Kurt E. Galbreath ◽  
Eric P. Hoberg
Keyword(s):  
North America ◽  
North American ◽  
Land Bridge ◽  
Biogeographic History ◽  
Staging Area ◽  
Ochotona Collaris ◽  
Bering Land Bridge ◽  
History Of ◽  
Host Parasite

Traditional concepts of the Bering Land Bridge as a zone of predominantly eastward expansion from Eurasia and a staging area for subsequent colonization of lower latitudes in North America led to early inferences regarding biogeographic histories of North American faunas, many of which remain untested. Here we apply a host–parasite comparative phylogeographical (HPCP) approach to evaluate one such history, by testing competing biogeographic hypotheses for five lineages of host-specific parasites shared by the collared pika ( Ochotona collaris ) and American pika ( Ochotona princeps ) of North America. We determine whether the southern host species ( O. princeps ) was descended from a northern ancestor or vice versa. Three parasite phylogenies revealed patterns consistent with the hypothesis of a southern origin, which is corroborated by four additional parasite lineages restricted to O. princeps . This finding reverses the traditional narrative for the origins of North American pikas and highlights the role of dispersal from temperate North America into Beringia in structuring northern diversity considerably prior to the Holocene. By evaluating multiple parasite lineages simultaneously, the study demonstrates the power of HPCP for resolving complex biogeographic histories that are not revealed by characteristics of the host alone.

A Short history of the post-graduate surgical training in Fiji - where to from here?

2018 ◽  
Vol 21 (2) ◽  
pp. 103-107 ◽  
Author(s):  
Jitoko Kelepi Cama ◽  
Sonal Singh Nagra
Keyword(s):  
Surgical Training ◽  
Training Programme ◽  
Post Graduate ◽  
School Of Medicine ◽  
Postgraduate Training Programme ◽  
The Pacific ◽  
National University ◽  
History Of ◽  
Training Of Surgeons ◽  
Pacific Island Nations

Post-graduate surgical training at the Fiji National University (FNU), previously known as the Fiji School of Medicine) has recently been updated by incorporating elements from the Royal Australasian College of Surgeons (RACS) training curriculum. The revised curriculum maintains strong contextual relevance to the needs and pathologies of the Pacific Island nations.  This paper outlines why the FNU surgical postgraduate training programme should be applauded as a successful programme in the training of surgeons for the region.

Oceans and Landless Farms: Linking Southern and Northern Shadow Places of Industrial Livestock (1954–1975)

2020 ◽  
Author(s):  
Floor Haalboom
Keyword(s):  
Animal Feed ◽  
Marine Ecosystem ◽  
Global South ◽  
Humboldt Current ◽  
The Public ◽  
The Pacific ◽  
Production And Consumption ◽  
Boom And Bust ◽  
History Of ◽  
Global North

This article argues for more extensive attention by environmental historians to the role of agriculture and animals in twentieth-century industrialisation and globalisation. To contribute to this aim, this article focuses on the animal feed that enabled the rise of ‘factory farming’ and its ‘shadow places’, by analysing the history of fishmeal. The article links the story of feeding fish to pigs and chickens in one country in the global north (the Netherlands), to that of fishmeal producing countries in the global south (Peru, Chile and Angola in particular) from 1954 to 1975. Analysis of new source material about fishmeal consumption from this period shows that it saw a shift to fishmeal production in the global south rather than the global north, and a boom and bust in the global supply of fishmeal in general and its use in Dutch pigs and poultry farms in particular. Moreover, in different ways, the ocean, and production and consumption places of fishmeal functioned as shadow places of this commodity. The public health, ecological and social impacts of fishmeal – which were a consequence of its cheapness as a feed ingredient – were largely invisible on the other side of the world, until changes in the marine ecosystem of the Pacific Humboldt Current and the large fishmeal crisis of 1972–1973 suddenly changed this.

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